Patent Application
20230125313
This disclosure relates to the technical field of batteries, and in particular, to an end cap assembly, a housing assembly, a battery cell, a battery, and an electrical device.
Due to advantages such as a high energy density, a high power density, reusability for many cycles, a long shelf life, batteries such as lithium-ion batteries have been widely used in electric vehicles.
However, increasing the battery life of electric vehicles has always been a tricky problem in the industry.
An objective of this disclosure is to improve performance of lithium-ion batteries.
According to a first aspect of this disclosure, an end cap assembly is provided, including:
In the end cap assembly according to this embodiment, the first through-hole configured to inject the electrolytic solution is made on the pressure relief component, and the first through-hole is closed by the closing component. The closing component is detachably disposed on the pressure relief component so as to implement detachment between the closing component and the pressure relief component to enable electrolyte refilling, thereby effectively alleviating capacity fading of the battery cell and improving the service life of the battery cell. Moreover, the first through-hole located on the pressure relief component can implement functions of both electrolyte refilling and release of the internal pressure of the battery cell, reduce the area occupied by the components on the end cap body, and vacate more space for battery assembling and circuit layout.
In some embodiments, the end cap assembly further includes: an insulation piece, disposed on a side that is of the end cap body and that is close to an interior of the battery cell, where the insulation piece abuts on the pressure relief component to support the pressure relief component.
The end cap assembly according to this embodiment abuts on the pressure relief component through the insulation piece, so as to support the pressure relief component and equalize an external force received by the pressure relief component. This prevents the pressure relief component from being damaged during detachment and attachment of the closing component, improves reliability of the battery cell during electrolyte refilling, and increases the service life of the battery cell.
In some embodiments, a snap-fit structure is disposed between the pressure relief component and the insulation piece. The snap-fit structure is configured to limit torsional deformation of the pressure relief component with respect to the end cap body along a circumference of the pressure relief component.
In the end cap assembly according to this embodiment, the snap-fit structure is disposed between the insulation piece and the pressure relief component to equalize a circumferential external force received by the pressure relief component. This prevents the pressure relief component from being damaged during detachment and attachment of the cover body, improves reliability of the battery cell during electrolyte refilling, and increases the service life of the battery cell.
In some embodiments, the snap-fit structure includes a first protruding portion and a recessed portion that fit with each other. The first protruding portion is disposed on a surface that is of the pressure relief component and that is oriented toward the insulation piece. The recessed portion is disposed on a surface that is of the insulation piece and that is oriented toward the pressure relief component.
In this embodiment, the snap-fit structure with the protruding portion fitted with the recessed portion enables the insulation piece to exert a reliable circumferential restraint effect on the pressure relief component, and prevents torsional deformation of the pressure relief component along the circumference of the pressure relief component with respect to the end cap body, so as to reduce the force received at an actuation mechanism or a fragile structure of the pressure relief component, and improve structural stability of the pressure relief component.
In some embodiments, a plurality of snap-fit structures are disposed. The plurality of snap-fit structures are evenly distributed circumferentially around an axis of the pressure relief component.
In this embodiment, a plurality of snap-fit structures are evenly distributed circumferentially around the axis of the pressure relief component. In this way, a circumferential supporting force exerted by the insulation piece on the pressure relief component is more equalized during electrolyte refilling after the cover body is unscrewed, and the circumferential external force received by the pressure relief component is equalized along the entire circumferential direction. This improves the effect of protecting the pressure relief component during detachment and attachment of the cover body, prevents the pressure relief component from being damaged during detachment and attachment of the cover body, improves reliability of the battery cell during electrolyte refilling, and increases the service life of the battery cell.
In some embodiments, a positioning hole is made on an outer surface of the pressure relief component. The positioning hole is configured to assist in positioning the pressure relief component during closing of the first through-hole.
In this embodiment, during assembling of the end cap assembly or electrolyte refilling, tooling may be inserted into the positioning hole to provide a clamping force for the pressure relief component, so as to reduce the external force received by the pressure relief component along the thickness or circumference of the pressure relief component, prevent the pressure relief component from being stressed at the actuation mechanism or fragile structure, and improve the structural stability of the pressure relief component.
In some embodiments, the first through-hole is located at a center position of the pressure relief component.
This embodiment equalizes a radial width of the pressure relief component at a part outside the first through-hole, so as to equalize strength of the pressure relief component along the entire circumferential direction, prevent the pressure relief component from being actuated when the internal pressure of the battery cell does not reach the threshold, and improve safety of the battery cell in use. Moreover, this prevents an unequal force from being exerted on the entire circumferential direction of the pressure relief component during detachment and attachment of the closing component, and improves structural stability of the pressure relief component during detachment and attachment of the closing component.
In some embodiments, the pressure relief component includes an explosion-proof valve. The first through-hole is made on the explosion-proof valve.
This embodiment reduces difficulty of processing the explosion-proof valve, helps increase the area of the explosion-proof valve, and increases the pressure on the pressure relief component on condition that the internal air pressure of the battery cell remains constant. In this way, in a case that the battery cell is thermally runaway, gas in the battery cell can be quickly expelled, thereby improving safety of the battery cell in use.
In some embodiments, the explosion-proof valve includes:
The explosion-proof valve according to this embodiment adopts a thickness-varying structure, thereby making it convenient to not only dispose the fragile region on the explosion-proof valve, but also partially thicken a region in which the first through-hole is located, so as to design a connection structure between the closing component and the explosion-proof valve and increase the connection strength between the closing component and the explosion-proof valve, and in turn, improve reliability of design of integrating an electrolyte injection member with the pressure relief component.
In some embodiments, the explosion-proof valve further includes: a transition portion, connected between the first portion and the second portion along the radius of the explosion-proof valve.
In the explosion-proof valve according to this embodiment, the transition component is disposed between the first portion and the second portion, thereby implementing smooth transition between the first portion and the second portion, reducing the probability of stress concentration in the thickness-varying region, and in turn, improving the overall strength of the explosion-proof valve, and reducing the probability of deforming or damaging the explosion-proof valve during detachment and attachment of the closing component.
In some embodiments, the end cap assembly further includes: an insulation piece, disposed on a side that is of the end cap body and that is close to an interior of the battery cell, where a second through-hole is made on the insulation piece, and the second through-hole is configured to implement communication between the interior of the battery cell and the fragile region.
In this embodiment, the second through-hole is made on the insulation piece to form a passageway available for the gas inside the battery cell to reach the fragile region. In this way, when the internal pressure of the battery cell exceeds the threshold, the internal pressure or heat can be smoothly released through the explosion-proof valve, thereby improving safety of battery cell in use.
In some embodiments, a first groove is made on a surface that is of the insulation piece and that is oriented toward the end cap body. The second portion extends into the first groove.
In this embodiment, the second portion extends into the first groove, thereby maximally avoiding increase of the overall thickness of the end cap assembly on the basis of increasing the strength of the explosion-proof valve, thereby increasing the energy density without changing the size of the battery cell.
In some embodiments, the pressure relief component includes a plurality of explosion-proof valves. The plurality of explosion-proof valves are disposed independently at intervals along a periphery of the first through-hole.
In this embodiment, the first through-hole and the explosion-proof valve are disposed independently. Therefore, the thickness of a joint between the first through-hole and the explosion-proof valve is consistent with the thickness of the end cap body, thereby ensuring sufficient structural strength of the joint. In addition, the fragile region of the explosion-proof valve is independent of the electrolyte injection mechanism, so that the external force generated during detachment and attachment of the closing component is prevented from directly acting on the explosion-proof valve during the assembling of the end cap assembly or the electrolyte refilling, and the fragile region of the explosion-proof valve is prevented from being deformed or damaged.
In some embodiments, a plurality of second grooves are disposed on the pressure relief component. The second grooves form the explosion-proof valves. The explosion-proof valves include a fragile region. The fragile region is configured to be actuated when the internal pressure of the battery cell reaches the threshold, so as to release the internal pressure of the battery cell.
In this embodiment, the plurality of second grooves are disposed to form a plurality of independent explosion-proof valves to facilitate arrangement of the fragile region. In addition, the fragile region of the explosion-proof valves is independent of the electrolyte injection mechanism, so that the external force generated during detachment and attachment of the closing component is prevented from directly acting on the explosion-proof valves during the assembling of the end cap assembly or the electrolyte refilling, and the fragile region of the explosion-proof valves is prevented from being deformed or damaged.
In some embodiments, the pressure relief component is integrated with the end cap body.
In the structure provided in this embodiment, the pressure relief component is integrated with the end cap body, thereby increasing the connection strength between the pressure relief component and the end cap body, and saving a step of fixing the pressure relief component onto the end cap body. This reduces the manufacturing difficulty and cost of the end cap assembly, and prevents an actuating pressure on the explosion-proof valve from being affected by a welding stress generated when the fixing manner is welding or the like.
In some embodiments, a third through-hole is made on the end cap body. The pressure relief component is fixed inside the third through-hole.
In this embodiment, an independent pressure relief component is fixed to the end cap body, thereby reducing the manufacturing difficulty. The pressure relief component can be formed by stamping in advance and then fixed to the end cap body. In this way, poorly stamped parts in the pressure relief component can be eliminated, thereby reducing the reject rate of assembled finished products and reducing the production cost of products.
In some embodiments, a locking base is disposed on a hole wall of the third through-hole. The locking base is disposed on a side that is of the end cap body and that is close to an interior of the battery cell. The pressure relief component abuts against the locking base to connect to the end cap body.
In this embodiment, the pressure relief component abuts against the locking base from inside. The locking base may serve as a main body for bearing the air pressure, thereby reducing the force on the joint between the pressure relief component and the end cap body, reducing the probability of seal failure caused by a creep of the joint between the pressure relief component and the end cap body after long-term use of the battery cell, and increasing the service life of the battery cell.
In some embodiments, the end cap assembly further includes a protection sheet. The protection sheet is affixed to a surface that is of the pressure relief component and that is away from the interior of the battery cell.
This embodiment prevents external impurities or moisture from entering the battery cell through the closing component, and improves airtightness of the end cap assembly.
In some embodiments, the closing component includes:
In some embodiments, an accommodation portion is further disposed on the pressure relief component. The accommodation portion is disposed on the pressure relief component and disposed along a circumference of the first through-hole. The cover body includes a limiting portion.
When the cover body rotates to a first position, the limiting portion is located in the accommodation portion to restrict the cover body from detaching from the pressure relief component. When the cover body rotates to a second position, the limiting portion is staggered from the accommodation portion along the circumference of the first through-hole to implement detachment between the cover body and the pressure relief component.
In this embodiment, the first through-hole is opened and closed by rotating the cover body, so as to form a detachable structure between the cover body and the pressure relief component, and prevent the electrolyte injection structure from being damaged during opening of the cover body. Further, the first through-hole can be reliably closed after completion of electrolyte refilling, thereby ensuring reliability of the battery cell in use after the electrolyte refilling. Therefore, the appearance of the secondary battery cell remains the same as before the electrolyte refilling, without affecting the use of the battery cell after the electrolyte refilling. Moreover, because the first through-hole is closed by directly rotating the cover body, the sealing of the first through-hole is implemented without laser welding, thereby saving a step of cleaning the first through-hole before the laser welding, and improving the production efficiency of the battery cell. In addition, the first through-hole is opened and closed by rotating the cover body, thereby reducing the large external force exerted on the pressure relief component along the thickness during detachment and attachment of the cover body, and preventing the pressure relief component from deforming inward or outward.
In some embodiments, the cover body further includes a body portion. The body portion is configured to cover at least a part of the sealing element. The limiting portion is connected to the body portion and extends along a radius of the first through-hole.
In some embodiments, the pressure relief component further includes a guide portion. The guide portion communicates with the accommodation portion. The limiting portion is configured to enter the accommodation portion through the guide portion, or detach from the pressure relief component through the guide portion.
In some embodiments, the pressure relief component includes a pressure relief body and a mounting component. The mounting component is disposed on a surface of the pressure relief body and disposed around the first through-hole. The accommodation portion is disposed in the mounting component, or the accommodation portion is formed by being enclosed with the mounting component and the pressure relief body.
In this embodiment, the pressure relief component is designed as a discrete structure. The pressure relief component is in a thin plate-like structure on which a complex structure is hardly processible. Therefore, the mounting component disposed facilitates formation of the accommodation portion, and reduces the processing difficulty of the pressure relief component.
According to a second aspect of this disclosure, a housing assembly is provided, applicable to a battery cell and including:
According to a third aspect of this disclosure, a battery cell is provided, including:
According to a fourth aspect of this disclosure, a battery is provided, including the battery cell according to the foregoing embodiments.
According to a fifth aspect of this disclosure, an electrical device is provided, including the battery cell according to the foregoing embodiment, where the battery cell is configured to provide electrical energy.
According to a sixth aspect of this disclosure, an electrolyte injection method of a battery cell is provided, including:
In some embodiments, the closing component includes: a sealing element and a cover body. The sealing element is configured to seal the first through-hole. The cover body is configured to cover at least a part of the sealing element. The mounting a closing component onto the pressure relief component to close the first through-hole includes:
This embodiment not only avoids the welding step, but also avoids a plurality of subsequent steps such as cleaning up the weld-induced welding spatters and drying the liquid that remains after the cleaning. Therefore, this disclosure can improve the production efficiency of the battery cell. In this disclosure, the closing component is mounted on the pressure relief component to close the first through-hole, and the electrolyte injection member is integrated with the pressure relief component to achieve space efficiency and facilitate electrolyte refilling operations.
In some embodiments, the electrolyte injection method of a battery cell further includes:
This embodiment can implement flexible and convenient detachment of the cover body. Therefore, when the electrolytic solution is deficient or deteriorated, the closing component is conveniently detachable for electrolyte refilling or degassing in the battery cell.
In some embodiments, the electrolyte injection method of a battery cell further includes: assisting, during closing of the first through-hole, in positioning the pressure relief component through a positioning hole located on an outer surface of the pressure relief component.
In this embodiment, during assembling of the battery cell or electrolyte refilling, tooling may be inserted into the positioning hole to provide a clamping force for the pressure relief component, so as to reduce the external force received by the pressure relief component along the thickness or circumference of the pressure relief component, prevent the pressure relief component from being stressed at the actuation mechanism or fragile structure, and improve the structural stability of the pressure relief component.
According to a seventh aspect of this disclosure, an electrolyte injection device is provided, applicable to a battery cell and including:
In the end cap assembly according to embodiments of this disclosure, the first through-hole configured to inject the electrolytic solution is made on the pressure relief component, and the first through-hole is closed by the closing component. The closing component is detachably disposed on the pressure relief component so as to implement detachment between the closing component and the pressure relief component to enable electrolyte refilling. Through the convenient electrolyte refilling, this disclosure effectively alleviates capacity fading of the battery cell and improves the service life of the battery cell. Moreover, the first through-hole located on the pressure relief component can reduce the area occupied by the components on the end cap body, implement functions of both electrolyte refilling and release of the internal pressure of the battery cell, and vacate more space for battery cell assembling and circuit layout.
The drawings described herein are intended to enable a further understanding of this disclosure, and constitute a part of this disclosure. The exemplary embodiments of this disclosure and the description thereof are intended to explain this disclosure but not to constitute any undue limitation on this disclosure.
The following describes this disclosure in detail. In the following paragraphs, different aspects of the embodiments are defined in more detail. Unless otherwise expressly specified, the aspects so defined can be combined with any other aspect or aspects. In particular, any feature considered to be preferred or advantageous may be combined with one or more other features considered to be preferred or advantageous.
The terms “first”, “second”, and the like used in this disclosure are merely intended for ease of description, and are used to distinguish different components with the same name, but do not indicate a chronological order or priority order.
In addition, when one element is referred to as being “on” another element, the element may be directly on the other element, or may be indirectly on the other element with one or more intermediate elements in between. In addition, when one element is referred to as being “connected to” another element, the element may be directly connected to the other element, or may be indirectly connected to the other element with one or more intermediate elements in between. In the description hereinafter, elements are the same as long as they are denoted by the same reference numeral.
“A plurality of” referred to in this disclosure means two or more (including two). Similarly, “a plurality of groups” means two or more groups (including two groups).
In order to clearly describe the directions and positions in the following embodiments, a coordinate system shown in
There are many problems affecting the service life of a lithium-ion battery cell. Over the years, those skilled in the art have tried solving such problems from many different angles, but desired results have not been achieved yet.
In the invention and creation process of this disclosure, the inventor has found, through numerous tests and verifications, that one of the factors affecting the service life of a battery is that the battery undergoes a plurality of charge-and-discharge cycles during use, and an electrolytic solution inside the battery cell unavoidably incurs irreversible reaction consumption so that an available capacity of the battery cell fades accordingly. Therefore, the inventor finds that, if the electrolytic solution inside the battery cell is supplemented during the use of the battery cell, the capacity fading of the battery cell can be effectively alleviated, and the service life of the battery cell can be improved.
A lithium-ion battery cell includes four main parts: a positive electrode material, a negative electrode material, an electrolytic solution, and a separator. The electrolytic solution is an ionic conductor that conducts between a positive electrode and a negative electrode of the battery cell, and generally includes two parts: electrolyte lithium salt and an organic solvent. High requirements are imposed on structural airtightness of the battery cell in order to prevent the electrolytic solution from seeping and polluting surrounding air and environment during use, or prevent moisture or metal particles from entering the interior of the battery cell to cause a short circuit between the positive electrode and the negative electrode. In the related art known to the inventor, electrolyte injection for the battery cell is usually carried out in a production stage. After completion of the electrolyte injection, an injection hole is usually closed off by laser welding in order to ensure airtightness of the battery cell.
Such a battery cell is difficult to be refilled with the electrolytic solution during use. To refill with the electrolytic solution anyway, a laser weld structure has to be destroyed, and can hardly be re-sealed. In addition, this causes irreversible damage to the structure of the battery cell, and affects the performance of the battery cell in use.
In view of this, this disclosure aims to provide a battery cell with a detachable closing component for electrolyte refilling, so as to facilitate detachment of the closing component for a refill and close off the injection hole reliably after completion of the refill. However, with reference to structural characteristics and performance requirements of a lithium battery cell, many problems still need to be solved to design such a battery cell with a detachable closing component.
First, as shown in
Secondly, the pressure relief component 2 is designed in such a way that, the larger the area of the pressure relief component 2, the greater the pressure on the pressure relief component 2 on condition that the internal air pressure of the battery cell 400 remains constant. In this way, when the battery cell 400 is thermally runaway, the gas in the battery cell 400 can be quickly expelled to avoid the problem that the battery cell 400 still explodes due to a degassing amount smaller than a gassing amount. Therefore, the area of the pressure relief component 2 needs to be increased as much as practicable to improve safety of the battery cell 400 in use. Restricted by the total area of the end cap body 1, the increased area makes the arrangement space of the components on the end cap body 1 tighter. If the pressure relief component 2 is disposed on the closing component 3 instead so that the entire closing component 3 is detachable to implement electrolyte refilling, the size of the closing component 3 will be increased correspondingly, and the energy density of the battery cell 400 will be reduced.
Therefore, the design of the battery cell 400 still can hardly meet various performance requirements such as a small size, a high energy density, ease of maintenance, reliability, safety, and a long service life.
On the basis of comprehensively considering the foregoing technical problems, in this disclosure, an electrolyte injection member is disposed on the pressure relief component 2 to implement electrolyte refilling and release of internal pressure of the battery cell 400 conveniently.
Specifically, electrolyte injection is a process by which an electrolytic solution is injected into the battery cell in a required amount through a reserved injection hole, and is divided into initial electrolyte injection and electrolyte refilling. Electrolyte refilling may also be referred to as supplementary electrolyte injection, subsequent electrolyte injection, and the like. The electrolyte refilling means a process of supplementing or replacing the electrolytic solution for a battery cell, or adding or supplementing any solid, liquid, or gas into the battery cell. Through the convenient electrolyte refilling, this disclosure effectively alleviates capacity fading of the battery cell and improves the service life of the battery cell 400.
Specifically, the pressure relief component 2 means an element or component that is actuated to relieve an internal pressure or temperature when the internal pressure or temperature of the battery cell 400 reaches a preset threshold. The threshold may vary depending on design requirements. The threshold may depend on the material of one or more of the positive electrode plate, the negative electrode plate, the electrolytic solution, or the separator in the battery cell 400. The pressure relief component 2 may be in the form of an explosion-proof valve, a gas valve, a pressure relief valve, a safety valve, or the like, and may specifically adopt a pressure-sensitive or temperature-sensitive element or structure. To be specific, when the internal pressure or temperature of the battery cell 400 reaches the preset threshold, the pressure relief component 2 is actuated or a fragile structure disposed in the pressure relief component 2 is damaged to form a vent or passageway for relieving the internal pressure or temperature.
The term “actuated” mentioned in this disclosure means that the pressure relief component 2 performs an action or is activated to a given state so that the internal pressure and temperature of the battery cell 400 is relieved. The actions performed by the pressure relief component 2 may include, but are not limited to, rupturing, shattering, tearing, or opening at least a part of the pressure relief component 2, or the like. When the pressure relief component 2 is actuated, high-temperature and high-pressure substances inside the battery cell 400 are expelled as emissions out of the actuated position. In this way, the pressure and temperature of the battery cell 400 are relieved under a circumstance of a controllable pressure or temperature to avoid potential severer accidents.
An electrical device includes a battery cell 400 configured to provide electrical energy for the device. The device may be a mobile phone, a portable device, a notebook computer, an electric power cart, an electric vehicle, a ship, a spacecraft, an electric toy, an electric tool. For example, the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, and the like. The electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, an electric airplane toy, and the like. The electric tool includes an electric tool for metal cutting, an electric grinding tool, an electric assembly tool, an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an electric impact drill, a concrete vibrator, and an electric planer.
As shown in
In order to achieve a higher power of the battery cell 400 to meet practical requirements, as shown in
As shown in
In order for a person skilled in the art to clearly understand the improvements made by this disclosure, an overall structure of the battery cell 400 is described first.
As shown in
One or more electrode assemblies 30 may be disposed depending on actual use requirements. As shown in
The end cap assembly 10 is disposed on the top of the electrode assembly 30. As shown in
After the overall structure and application of the battery cell 400 are described, the improvements made by this disclosure will be described in detail below. First, an example is described in which both a closing component 3 and a pressure relief component 2 are disposed in an end cap assembly 10. A plurality of embodiments of this disclosure are described based on this structure.
In some embodiments, as shown in
The end cap body 1 may be in a rectangular plate-like structure. The pressure relief component 2 is connected to the end cap body 1. The pressure relief component 2 is configured to be actuated when an internal pressure of the battery cell 400 reaches a threshold, so as to release the internal pressure of the battery cell 400. The pressure relief component 2 may be disposed at any position between two terminals 5, for example, between the two terminals 5 and at a middle position of the end cap body 1 along a length direction. A first through-hole 21 configured to inject an electrolytic solution is disposed on the pressure relief component 2. The first through-hole 21 may be a circular, elliptical, or polygonal hole or a hole in other shapes. Benchmarked against the battery cell 400, the first through-hole 21 may be disposed along a height direction of the battery cell 400, that is, along a thickness direction of the end cap body 1; or may be disposed obliquely. A sidewall of the first through-hole 21 may be located within an outer contour of the pressure relief component 2.
The closing component 3 is detachably disposed on the pressure relief component 2. The closing component 3 is configured to close the first through-hole 21 when being mounted on the pressure relief component 2, and expose the first through-hole 21 when detaching from the pressure relief component 2 so that an electrolytic solution can be injected in this state.
In this disclosure, electrolyte refilling can be implemented by detaching the closing component 3 from a pressure relief body 25. Through the convenient electrolyte refilling, this disclosure effectively alleviates capacity fading of the battery cell 400 and improves the service life of the battery cell 400. Further, the first through-hole 21 communicates the interior of the housing 40 with external atmosphere after the closing component 3 is detached, thereby expelling the gas out of the housing 40 or air bubbles between electrode plates. By expelling the air bubbles between the electrode plates, a clearance between the electrode plates is shortened, thereby improving cycle performance of the battery cell 400, and further, improving the service life of the battery cell 400. By expelling the gas out of the housing of the battery cell 400, this disclosure can also release pressure in the housing 40, thereby reducing a continuous force exerted by the gas in the housing 40 on the pressure relief component 2, reducing risks of shortening the battery life due to electrolyte leakage out of or moisture entry into the battery cell 400 in a case of a creep or rupture of the pressure relief component 2, and in turn, improving the service life of the battery cell.
This disclosure forms a detachable structure between the closing component 3 and the pressure relief component 2, and prevents the electrolyte injection structure from being damaged during opening of the opening component 3. Further, the first through-hole 21 can be reliably closed after completion of electrolyte refilling, thereby ensuring reliability of the battery cell in use after the electrolyte refilling. Therefore, the appearance of the battery cell 400 remains the same as before the electrolyte refilling, without affecting the use of the battery cell after the electrolyte refilling. Further, because the first through-hole 21 is closed by directly using the detachable closing component 3, the sealing of the first through-hole 21 is implemented without laser welding, thereby saving a step of cleaning the first through-hole 21 before the laser welding, and improving the production efficiency of the battery cell.
In this disclosure, the first through-hole 21 configured to inject an electrolytic solution is disposed on the pressure relief component 2, and the first through-hole 21 is closed by the closing component 3. This is equivalent to integrating the closing component 3 with the pressure relief component 2, thereby not only reducing the area occupied by the closing component 3 and the pressure relief component 2 on the end cap body 1, but also reducing the number of avoidance holes or slots required on a press-fitting tool when a plurality of battery cells 400 are press-fitted to form a battery module 300. Similarly, a wiring harness fender is disposed on the top of the plurality of battery cells 400, thereby reducing the number of avoidance holes or slots required on the wiring harness fender. Moreover, the number of avoidance holes or slots required on the tooling and the wiring harness fender can be halved. In this way, the end cap assembly 10 according to this disclosure can greatly reduce the structural complexity of the wiring harness fender and the assembling tool in the battery module 300.
Secondly, during designing of the pressure relief component 2, in order to improve the degassing safety of the battery cell 400, the area of the pressure relief component 2 needs to be increased as much as practicable during designing of the pressure relief component 2. In the end cap assembly 10 according to this disclosure, the closing component 3 is integrated with the pressure relief component 2, thereby reducing the space occupied by the closing component 3 and the pressure relief component 2 on the end cap body 1 of the end cap assembly 10. Therefore, such an arrangement helps increase the area of the pressure relief component 2 on condition that the area of the end cap body 1 remains constant, and helps increase the pressure on the pressure relief component 2 on condition that the internal air pressure of the battery cell 400 remains constant. In this way, when the battery cell 400 is thermally runaway, the gas in the battery cell 400 can be quickly expelled to avoid the problem that the battery cell 400 explodes due to a degassing amount smaller than a gassing amount, thereby improving safety of the battery cell 400 in use.
In the end cap assembly 10 according to this disclosure, the first through-hole 21 is made on the pressure relief component 2 instead of removing the entire pressure relief component 2 for a purpose of electrolyte injection. In this way, the area of the first through-hole 21 is smaller than that of the pressure relief component 2, thereby reducing the size of the closing component 3 on the basis of increasing the area of the pressure relief component 2, and in turn, increasing the energy density of the battery cell 400.
In some embodiments, as shown in
As shown in
During detachment and attachment of the closing component 3, an external force is inevitably exerted on the pressure relief component 2. For example, a downward pressure, an upward pulling force, or a circumferential rotational force is exerted on the pressure relief component 2. Generally, an actuation mechanism or a fragile structure is disposed on the pressure relief component 2, and is actuated when the internal pressure of the battery cell 400 reaches a preset threshold, so as to release the internal pressure of the battery cell 400. The external force so exerted on the pressure relief component 2 may cause deformation or damage to the actuation mechanism or fragile structure, and affect normal pressure relief.
The end cap assembly 10 according to this disclosure abuts on the pressure relief component 2 through the insulation piece 4, so as to support the pressure relief component 2 and equalize the external force received by the pressure relief component 2. This prevents the pressure relief component 2 from being damaged during detachment and attachment of the closing component 3, improves reliability of the battery cell 400 during electrolyte refilling, and increases the service life of the battery cell 400. Moreover, when the end cap assembly 10 is subjected to the external force, the support by the insulation piece 4 can prevent the pressure relief component 2 from being deformed or damaged, so as to ensure fulfillment of the expected pressure relief effect and improve safety of the battery cell 400 in use. For example, when the battery cell 400 is mounted in a vehicle 100, the vehicle 100 is subjected to vibration or external impact during movement, and the support by the insulation piece 4 can prevent the pressure relief component 2 from deforming under the action of vibration or impact.
In some embodiments, as shown in
As shown in
In some embodiments, as shown in
For example, with respect to the shape, the first protruding portion 225 and the recessed portion 42 may be dot-like, strip-like, block-like structures. With respect to the position, the first protruding portion 225 and the recessed portion 42 may be disposed on a plane on which the pressure relief component 2 abuts on the insulation piece 4. Alternatively, a circumferential fitting structure may be disposed between the pressure relief component 2 and the insulation piece 4, and the snap-fit structure is disposed on the circumferential fitting structure. With respect to the number of the snap-fit structures, one or more snap-fit structures may be disposed. The position of the first protruding portion 225 is interchangeable with the position the recessed portion 42. The first protruding portion 225 is disposed on the insulation piece 4, and the recessed portion 42 is disposed on the pressure relief component 2. Any structure that can limit the torsional deformation of the pressure relief component 2 along the circumference falls within the protection scope of this disclosure.
In this embodiment, the snap-fit structure with the first protruding portion 225 fitted with the recessed portion 42 enables the insulation piece 4 to exert a reliable circumferential restraint effect on the pressure relief component 2, and prevents torsional deformation of the pressure relief component 2 along the circumference of the pressure relief component 2 with respect to the end cap body 1, so as to reduce the force received at the actuation mechanism or fragile structure of the pressure relief component 2, and improve structural stability of the pressure relief component 2. Moreover, because the pressure relief component 2 is of lesser thickness and lesser strength, the first protruding portion 225 disposed on the pressure relief component 2 can increase structural strength to ensure normal pressure relief performance.
Optionally, the first protruding portion 225 may be in transition fit or interference fit with the recessed portion 42 to ensure a circumferential restraint effect exerted by the insulation piece 4 on the pressure relief component 2.
In some embodiments, a plurality of snap-fit structures are disposed. The plurality of snap-fit structures are evenly distributed circumferentially around an axis of the pressure relief component 2.
As shown in
Alternatively, on the basis of
In this embodiment, a plurality of snap-fit structures are evenly distributed circumferentially around the axis of the pressure relief component 2. In this way, a circumferential supporting force exerted by the insulation piece 4 on the pressure relief component 2 is more equalized during electrolyte refilling after the cover body 32 is unscrewed, and the circumferential external force received by the pressure relief component 2 is equalized along the entire circumferential direction. This improves the effect of protecting the pressure relief component 2 during detachment and attachment of the cover body 32, prevents the pressure relief component 2 from being damaged during detachment and attachment of the cover body 32, improves reliability of the battery cell 400 during electrolyte refilling, and increases the service life of the battery cell 400.
In some embodiments, as shown in
In some embodiments, as shown in
This embodiment equalizes a radial width of the pressure relief component 2 at a part outside the first through-hole 21, so as to equalize strength of the pressure relief component 2 along the entire circumferential direction, prevent the pressure relief component from being actuated when the internal pressure of the battery cell 400 does not reach the threshold, and improve safety of the battery cell 400 in use. Moreover, this prevents an unequal force from being exerted on the entire circumferential direction of the pressure relief component 2 during detachment and attachment of the closing component 3, and improves structural stability of the pressure relief component 2 during detachment and attachment of the closing component 3. Optionally, the first through-hole 21 may instead be located in a region on the pressure relief component 2 other than the center position.
In some embodiments, as shown in
For example, one explosion-proof valve 22 is disposed, and the first through-hole 21 is made at a center position of the explosion-proof valve 22. This structure reduces the processing difficulty of the explosion-proof valve 22, helps increase the area of the explosion-proof valve 22, and increases the pressure on the pressure relief component 2 on condition that the internal air pressure of the battery cell 400 remains constant. In this way, in a case that the battery cell 400 is thermally runaway, gas in the battery cell 400 can be quickly expelled to avoid the problem that the battery cell 400 explodes due to a degassing amount smaller than a gassing amount, thereby improving safety of the battery cell 400 in use. Alternatively, a plurality of explosion-proof valves 22 are disposed, and the first through-hole 21 is made on one of the explosion-proof valves 22, or the first through-hole 21 is made on at least a part of the explosion-proof valves 22.
In some embodiments, as shown in
The first portion 221 takes the shape of an annular structure. The first portion 221 includes a fragile region 224. The fragile region 224 is located outside the first through-hole 21, and extends along a circumference of the explosion-proof valve 22. The fragile region 224 is configured to be actuated to break when the internal pressure of the battery cell 400 reaches the threshold, so as to release the internal pressure of the battery cell 400. An outer edge of the first portion 221 may be located at an outer rim of the fragile region 224, or may be located at a position that is offset outward from the outer rim of the fragile region 224 by a given distance.
For example, the fragile region 224 extends along the entire circumferential direction of the explosion-proof valve 22; or extends along a part of the circumference of the explosion-proof valve 22. The fragile region 224 may extend continuously (for example, along ¾ of the circumference) or a plurality of sections of the fragile region may be disposed at intervals. In this way, after the fragile region 224 is actuated to break, the explosion-proof valve 22 is still connected to the end cap body 1, and is prevented from flying into other components and affecting the normal operation of the devices such as the vehicle 100, thereby improving safety of the devices in use.
As shown in
Optionally, a melting point of the fragile region 224 is lower than a melting point of other regions on the explosion-proof valve 22.
As shown in
The explosion-proof valve 22 according to this embodiment adopts a thickness-varying structure, thereby making it convenient to not only dispose the fragile region 224 on the explosion-proof valve 22, but also partially thicken a region in which the first through-hole 21 is located, so as to facilitate design of a connection structure between the closing component 3 and the explosion-proof valve 22 and increase the connection strength between the closing component 3 and the explosion-proof valve 22, and in turn, improve reliability of design of integrating the closing component 3 with the pressure relief component 2.
In some embodiments, as shown in
In the explosion-proof valve 22 according to this embodiment, the transition portion 223 is disposed between the first portion 221 and the second portion 222, thereby implementing smooth transition between the first portion 221 and the second portion 222, reducing the probability of stress concentration in the thickness-varying region, and in turn, improving the overall strength of the explosion-proof valve 22, and reducing the probability of deforming or damaging the explosion-proof valve 22 during detachment and attachment of the closing component 3. Optionally, the first portion 221 may be directly connected to the second portion 222 instead.
In some embodiments, as shown in
In this embodiment, the second through-hole 43 is made on the insulation piece 4 to form a passageway available for the gas inside the battery cell 400 to reach the fragile region 224. In this way, when the internal pressure of the battery cell 400 exceeds the threshold, the internal pressure or heat can be smoothly released through the explosion-proof valve 22, thereby improving safety of battery cell 400 in use.
In some embodiments, as shown in
In order to increase the strength of the explosion-proof valve 22, the second portion 222 is thickened. In this embodiment, the second portion 222 extends into the first groove 41, thereby maximally avoiding increase of the overall thickness of the end cap assembly 10 on the basis of increasing the strength of the explosion-proof valve 22, thereby increasing the energy density without changing the size of the battery cell 400.
On this basis, as shown in
Optionally, as shown in
In some embodiments, as shown in
In this embodiment, the first through-hole 21 and the explosion-proof valve 22 are disposed independently. Therefore, the thickness of a joint between the first through-hole 21 and the explosion-proof valve 22 is consistent with the thickness of the end cap body 1, thereby ensuring sufficient structural strength of the joint. In addition, the fragile region 224 of the explosion-proof valve 22 is independent of the electrolyte injection mechanism, so that the external force generated during detachment and attachment of the closing component 3 is prevented from directly acting on the explosion-proof valve 22 during the assembling of the end cap assembly 10 or the electrolyte refilling, and the fragile region 224 of the explosion-proof valve 22 is prevented from being deformed or damaged.
In some embodiments, as shown in
In this embodiment, the plurality of second grooves 24 are made to form a plurality of independent explosion-proof valves 22 to facilitate arrangement of the fragile region 224. In addition, the fragile region 224 of the explosion-proof valves 22 is independent of the closing component 3, so that the external force generated during detachment and attachment of the closing component 3 is prevented from directly acting on the explosion-proof valves 22 during the assembling of the end cap assembly 10 or the electrolyte refilling, and the fragile region 224 of the explosion-proof valves 22 is prevented from being deformed or damaged.
In some embodiments, as shown in
In the structure provided in this embodiment, the pressure relief component 2 is integrated with the end cap body 1, thereby increasing the connection strength between the pressure relief component 2 and the end cap body 1, and saving a step of fixing the pressure relief component 2 onto the end cap body 1. This reduces the manufacturing difficulty and cost of the end cap assembly 10, and prevents an actuating pressure on the explosion-proof valve 22 from being affected by a welding stress generated when the fixing manner is welding or the like.
In some embodiments, as shown in
In this embodiment, an independent pressure relief component 2 is fixed to the end cap body 1, thereby reducing the manufacturing difficulty. The pressure relief component 2 can be formed by stamping in advance and then fixed to the end cap body 1. In this way, poorly stamped parts in the pressure relief component 2 can be eliminated, thereby reducing the reject rate of assembled finished products and reducing the production cost of products.
In some embodiments, as shown in
The air pressure inside the battery cell 400 acts from inside to outside. Therefore, in this embodiment, the pressure relief component 2 abuts against the locking base 121 from inside. The locking base 121 may serve as a main body for bearing the air pressure, thereby reducing the force on the joint between the pressure relief component 2 and the end cap body 1, reducing the probability of seal failure caused by a creep of the joint between the pressure relief component 2 and the end cap body 1 after long-term use of the battery cell 400, and increasing the service life of the battery cell 400. Optionally, as shown in
In some embodiments, as shown in
In some embodiments, as shown in
The cover body 32 may hold down the sealing element 31 so that the sealing element 31 is deformed to improve the sealing effect, or may just contact the sealing element 31 to limit the degree of freedom of the sealing element along the height direction. In a case that the sealing element 31 is in tight fit with the first through-hole 21 and capable of independently closing the first through-hole 21, the cover body 32 may be spaced apart from the sealing element 31 in the height direction. The cover body 32 may fully cover the sealing element 31 to exert a pressure on the sealing element 31 to limit the position or prevent external impurities from entering the battery. In a case that the sealing element 31 is in tight fit with the first through-hole 21 and capable of independently closing the first through-hole 21, the cover body 32 may partly cover the sealing element 31.
In this embodiment, the first through-hole 21 is opened and closed by rotating the cover body 32, so as to form a detachable structure between the cover body 32 and the pressure relief component 2, and prevent the electrolyte injection structure from being damaged during opening of the cover body 32. Further, the first through-hole 21 can be reliably closed after completion of electrolyte refilling, thereby ensuring reliability of the battery cell 400 in use after the electrolyte refilling. Therefore, the appearance of the secondary battery cell 400 remains the same as before the electrolyte refilling, without affecting the use of the battery cell after the electrolyte refilling. Moreover, because the first through-hole 21 is closed by directly rotating the cover body 32, the sealing of the first through-hole 21 is implemented without laser welding, thereby saving a step of cleaning the first through-hole 21 before the laser welding, and improving the production efficiency of the battery cell 400. In addition, the first through-hole 21 is opened and closed by rotating the cover body 32, thereby reducing the large external force exerted on the pressure relief component 2 along the thickness during detachment and attachment of the cover body 32, and preventing the pressure relief component 2 from deforming inward or outward.
In some embodiments, an accommodation portion 23 is further disposed on the pressure relief component 2. The accommodation portion 23 is disposed on the pressure relief component 2 and disposed along a circumference of the first through-hole 21. The cover body 32 includes a limiting portion 322. A snap-fit structure is formed between the limiting portion 322 and the accommodation portion 23. When the cover body 32 rotates to a first position, the limiting portion 322 is located in the accommodation portion 23 to restrict the cover body 32 from detaching from the pressure relief component 2. When the cover body 32 rotates to a second position, the limiting portion 322 is staggered from the accommodation portion 23 along the circumference of the first through-hole 21 to implement detachment between the cover body 32 and the pressure relief component 2. Optionally, the cover body 32 may be detachably connected to the pressure relief component 2 by means such as screwing, snap-fastening, or the like instead.
In this embodiment, an extension length of the limiting portion 322 along the circumference of the first through-hole 21 and an extension width along the radius of the first through-hole 21 ensure sufficient strength of the snap-fit structure. The strength is enough to prevent the snap-fit structure from being damaged even if the structure has been detached and attached for many times, so as to ensure reliability and a relatively long service life of the battery cell 400 in use.
Moreover, the limiting portion 322 fits with or detaches from the accommodation portion 23 by rotating the cover body 32. Therefore, the structure is simple, the requirement on the fitting precision is relatively low, and the cover body is reusable. With respect to assembling and maintenance, the cover body 32 is easy to detach and attach, thereby improving the assembling efficiency of the battery cell 400 during production, and shortening the maintenance time during electrolyte refilling.
Further, as shown in
The cover body 32 is restricted from approaching, or detached from, the accommodation portion 23 by rotating. During the rotation, the limiting portion 322 may rub against an inner wall of the accommodation portion 23 to generate metal particles. In this disclosure, the accommodation portion 23 is located on the side that is of the pressure relief component 2 and that is away from the interior of the battery cell 400. Therefore, the metal particles generated during the rotation is prevented from directly falling into the housing 40 to cause a short circuit of the battery cell 400, thereby further improving safety of the battery cell 400. Optionally, the accommodation portion 23 may be directly disposed on a bottom face of the pressure relief component 2 instead.
In some embodiments, the cover body 32 further includes a body portion 321. The body portion 321 is configured to cover at least a part of the sealing element 31. The limiting portion 322 is connected to the body portion 321 and extends along a radius of the first through-hole 21.
In some embodiments, as shown in
As shown in
In some embodiments, as shown in
In some embodiments, as shown in
As shown in
When the cover body 32 needs to be mounted, a downward force is exerted on the cover body 32. A clearance is generated between the limiting portion 322 and the first limiting wall 23A through deformation of the sealing element 31. In this case, the cover body 32 is rotated to make the limiting portion 322 enter the accommodation portion 23 smoothly. After reaching the first position, the cover body 32 is released. The cover body 32 moves upward under an elastic action of the sealing element 31 until a top face of the limiting portion 322 abuts against the first limiting wall 23A. In this case, a clearance may appear between the bottom face of the limiting portion 322 and the second limiting wall 23B.
When the cover body 32 needs to be detached, a downward force is exerted on the cover body 32. A clearance is generated between the limiting portion 322 and the first limiting wall 23A through deformation of the sealing element 31. In this case, the cover body 32 is rotated so that the limiting portion 322 is smoothly staggered from the accommodation portion 23 circumferentially and integrally located inside the guide portion 27. In this case, the cover body 32 reaches the second position, and is removed for electrolyte injection.
In some embodiments, a stop portion 231 is disposed inside the accommodation portion 23, and is configured to limit a maximum rotational stroke of the limiting portion 322. One stop portion 231 may be disposed on each accommodation portion 23. The stop portion 231 can block the rotation of the limiting portion 322 to prevent the limiting portion 322 from directly spinning out of the accommodation portion 23.
When the maximum rotational stroke is reached, a side of the limiting portion 322 along the circumference fits the stop portion 231 exactly. For example, two limiting portions 322 are disposed evenly along the circumference of the body portion 321. Both sides of the limiting portion 322 along the circumference are parallel to a center plane of the cover body 32. Correspondingly, the stop portions 231 of the two accommodation portions 23 are centrosymmetric about a center plane of the first through-hole 21. The two stop portions 231 are parallel to each other. Optionally, the side of the limiting portion 322 along the circumference may partially abut against the stop portion 231 instead.
In some embodiments, a limiting structure is disposed between the limiting portion 322 and the accommodation portion 23, and is configured to restrict the cover body 32 from being staggered and detached from the accommodation portion 23 when the cover body is in the first position. If the device that uses the battery cell 400 generates a large vibration or impact during operation, the limiting structure can implement a reliable snap-fit between the limiting portion 322 and the accommodation portion 23 when the cover body is in the first position, thereby preventing the limiting portion 322 from detaching from the accommodation portion 23 due to circumferential rotation, making the connection between the cover body 32 and the pressure relief component 2 more reliable, improving airtightness of the electrolytic solution, and in turn, ensuring reliability of the battery in use.
As shown in
As shown in
As shown in
As shown in
Such a sealing element 31 alone can seal the first through-hole 21. In a case of electrolyte refilling, the first through-hole 21 is still closed by the sealing element 31 after the cover body 32 is detached, and finally, the electrolytic solution can be injected by just detaching the sealing element 31. In a case of mounting the cover body 32, the first through-hole 21 is closed by the sealing element 31 first, and then the cover body 32 is mounted. In this way, during both detachment and attachment of the cover body 32, the first through-hole 21 is in a closed state, thereby further preventing a positive electrode and a negative electrode of the electrode assembly 30 from being short-circuited by metal chips that fall into the housing 40, where the metal chips are generated by friction between the cover body 32 and the accommodation portion 23 during rotation of the cover body. Therefore, relatively high working performance of the battery cell 400 is ensured.
To facilitate rotation of the cover body 32, a clamping portion 3211 is disposed on the body portion 321 of the cover body 32, and is configured to receive an external operation to drive the cover body 32 to rotate. By virtue of the clamping portion 3211 disposed, the tooling can coordinate with the clamping portion 3211 to rotate the cover body 32 conveniently, an external force can be applied conveniently to detach and attach the cover body 32, and a rotation angle of the cover body 32 is easily controllable. As shown in
In some embodiments, as shown in
In this embodiment, the pressure relief component 2 is designed as a discrete structure. The pressure relief component 2 is in a thin plate-like structure on which a complex structure is hardly processible. Therefore, the mounting component 26 disposed facilitates formation of the accommodation portion 23, and reduces the processing difficulty of the pressure relief component 2.
As shown in
As shown in
Such a structure can reduce the height of the mounting component 26 relative to the pressure relief body 25, so as to reduce the height by which the closing component 3 protrudes from the pressure relief body 25, and in turn, reduce the overall height of the battery. In addition, this can reduce the probability of collision between the closing component 3 and other components during mounting or use of the battery cell 400.
Specifically, the mounting component 26 may be fixed in the third groove 251 in various ways such as tight fit, bonding, fastener, or welding. As shown in
In this embodiment, the cover body 32 is disposed in the opening 263, thereby helping reduce the height by which the closing component 3 protrudes from the pressure relief body 25. This not only reduces the probability of collision between the closing component 3 and other components during the mounting or use of the battery cell 400, but also facilitates mounting of other members above the end cap assembly 10, such as a detection circuit configured to obtain a signal of the battery cell 400, in a case that the battery cell 400 is applied to a battery 200.
Specifically, as shown in
The mounting component 26 is disposed in a third groove 251, and the accommodation portion 23 is formed by being enclosed with a bottom wall of the limiting base 262, a sidewall of the mounting ring 261, and a bottom wall of the third groove 251. Therefore, the bottom wall of the limiting base 262 serves as a first limiting wall 23A, the bottom wall of the third groove 251 serves as a second limiting wall 12B, and the sidewall of the mounting ring 261 serves as a sidewall 12C.
The limiting base 262 may extend radially inward from an inner sidewall of the mounting ring 261, and the limiting base 262 extends circumferentially. For example, a plurality of limiting bases 262 are disposed circumferentially at intervals on the mounting ring 261. The plurality of limiting bases 262 may be evenly distributed. A guide portion 27 is formed between adjacent limiting bases 262. The guide portion 27 communicates with the accommodation portion 23. In some embodiments, as shown in
Specifically, as shown in
As shown in
As shown in
As shown in
Such a structure can reduce the overall height of the battery cell 400, increase the energy density, and reduce the probability of collision between the closing component 3 and other components during mounting or use of the battery cell 400.
To facilitate the limiting base 262 to enter the accommodation portion 23 by rotating, the height of the accommodation portion 23 is greater than that of the limiting base 262. After the limiting base 262 enters the accommodation portion 23, the top face of the limiting base 262 is brought into contact with the first limiting wall 23A under the elastic force of the sealing element 31, but the bottom face of the limiting base 262 is spaced from the second limiting wall 23B by a clearance. Therefore, in order to prevent the top face of the cover body 32 from exceeding the top face of the mounting component 26, the height of the cover body 32 is less than the height of the mounting component 26. Such a structure not only enables the cover body 32 to rotate smoothly, but also leaves a space for the mounting of the sealing element 31 on the basis of reducing the overall height of the battery.
The specific structure of each embodiment is described in detail below.
In order for the pressure relief component 2 to both facilitate arrangement of the thinned portion and ensure sufficient strength of connection to the closing component 3, as shown in
As shown in
To solve such a problem, as shown in
Further, as shown in
As shown in
The accommodation portion 23 is located on a side that is of the pressure relief component 2 and that is away from the housing 40, and is disposed along the circumference of the first through-hole 21. The accommodation portion 23 may be a cavity extending along a part of the circumference of the first through-hole 21. As shown in
As shown in
As shown in
A process of assembling the end cap assembly 10 according to a first embodiment is as follows: first, placing a mounting component 26 into a third groove 251, and welding; next, injecting an electrolytic solution from a first through-hole 21, and mounting a sealing element 31 upon completion of injection; subsequently, placing a cover body 32 onto a pressure relief component 2, where the cover body 32 covers at least a part of the sealing element 31, and the cover body 32 is placed in a second position where the limiting portion 322 is circumferentially staggered from the accommodation portion 23; finally, engaging a cross-recess-shaped clamping portion 3211 by using a special tool, applying a downward force to generate a clearance between the limiting portion 322 and the first limiting wall 23A, and rotating 90° to move the cover body 32 from the second position to a first position and cause the limiting portion 322 to enter the accommodation portion 23, so as to restrict the cover body 32 from detaching from the pressure relief component 2. After rotating in place, releasing the cover body 32, so that the cover body 32 abuts on the first limiting wall 23A after the cover body 32 receives an elastic force of the sealing element 31.
An electrolyte refilling process for the battery cell 400 is: engaging the cross-recess-shaped clamping portion 3211 by using a special tool, reversely rotating the cover body 32 until the cover body moves from the first position to the second position, removing the cover body 32, removing the sealing element 31, and, after the electrolytic solution e is injected, repeating the assembling process to finish maintenance for the battery cell 400.
As shown in
As shown in
As shown in
The first through-hole 21 and the explosion-proof valve 22 are disposed independently. Therefore, the thickness of a joint between the first through-hole 21 and the explosion-proof valve 22 is consistent with the thickness of the end cap body 1, thereby ensuring sufficient structural strength of the joint. In addition, the fragile region 224 of the explosion-proof valve 22 is independent of the electrolyte injection mechanism, so that the external force generated during detachment and attachment of the closing component 3 is prevented from directly acting on the explosion-proof valve 22 during the assembling of the end cap assembly 10 or the electrolyte refilling, and the fragile region 224 of the explosion-proof valve 22 is prevented from being deformed or damaged.
In some embodiments, as shown in
Based on the improvements made by the foregoing embodiments on the end cap assembly 10, another aspect of this disclosure further provides a housing assembly 410 applicable to a battery cell 400. In some embodiments, as shown in
In this embodiment, the first through-hole 21 may be disposed on any wall face of the housing 40, so that the first through-hole 21 can be located more flexibly. As shown in
As shown in
The housing assembly 410 according to this embodiment enables repeated detachment and attachment of the closing component 3 flexibly and conveniently. In a case that the electrolytic solution is deficient or deteriorated, the closing component 3 is conveniently detachable for electrolyte refilling and degassing in the battery cell 400. After completion of the electrolyte refilling, the first through-hole 21 for electrolyte refilling can be closed reliably, thereby ensuring reliability of the battery cell 400 in use after the electrolyte refilling, and the appearance of the battery keeps the same as before the electrolyte refilling.
Moreover, the first through-hole 21 configured to inject an electrolytic solution is disposed on the pressure relief component 2. This is equivalent to integrating the closing component 3 with the pressure relief component 2, thereby not only reducing the area occupied by the closing component 3 and the pressure relief component 2 on the end cap body 1, but also reducing the number of avoidance holes or slots required on tooling and a wiring harness fender during formation of a battery module 300, and in turn, reducing structural complexity of the wiring harness fender and the assembling tool for the battery module 300.
In addition, in the end cap assembly 10 according to this disclosure, the closing component 3 is integrated with the pressure relief component 2, thereby reducing the space occupied by the closing component 3 and the pressure relief component 2 on the end cap body 1 of the end cap assembly 10. Therefore, such an arrangement helps increase the area of the pressure relief component 2 on condition that the area of the end cap body 1 remains constant, and helps increase the pressure on the pressure relief component 2 on condition that the internal air pressure of the battery cell 400 remains constant. In this way, when the battery cell 400 is thermally runaway, the gas in the battery cell 400 can be quickly expelled to avoid the problem that the battery cell 400 explodes due to a degassing amount smaller than a gassing amount, thereby improving safety of the battery cell 400 in use.
In addition, in the end cap assembly 10 according to this disclosure, the first through-hole 21 is made on the pressure relief component 2 instead of making an injection hole by detaching the entire pressure relief component 2. In this way, the radial dimension of the first through-hole 21 is smaller than that of the pressure relief component 2, thereby reducing the size of the closing component 3 on the basis of increasing the area of the pressure relief component 2, and in turn, increasing the energy density of the battery cell 400.
For the embodiments of disposing the pressure relief component 2 and the closing component 3 on other surfaces of the housing 40, refer to the foregoing embodiments of disposing the pressure relief component 2 and the closing component 3 on the end cap body 1, details of which are omitted here.
As shown in
Alternatively, as shown in
As shown in
Step S101: Injecting an electrolytic solution through a first through-hole 21 on a pressure relief component 2 of the battery cell 400, where the pressure relief component 2 is disposed on a sidewall of a shell 410′, and the pressure relief component 2 is configured to be actuated when an internal pressure of the battery cell 400 reaches a threshold, so as to release the internal pressure of the battery cell 400; and
Step S102: Mounting a closing component 3 onto the pressure relief component 2 to close the first through-hole 21.
Step S102 is performed after step S101. Compared with the conventional method of closing the injection hole by laser welding, this disclosure not only avoids the welding step, but also avoids a plurality of subsequent steps such as cleaning up the weld-induced welding spatters and drying the liquid that remains after the cleaning. Therefore, this disclosure can improve the production efficiency of the battery cell. In this disclosure, the closing component 3 is mounted on the pressure relief component 2 to close the first through-hole 21, and the closing component 3 is integrated with the pressure relief component 2 to achieve space efficiency and facilitate electrolyte refilling operations.
In some embodiments, the closing component 3 includes: a sealing element 31 and a cover body 32. The sealing element 31 is configured to seal the first through-hole 21. The cover body 32 is configured to cover at least a part of the sealing element 31. The mounting a closing component 3 onto the pressure relief component 2 to close the first through-hole 21 in step S102 includes:
Step S102A: Placing the cover body 32 on the pressure relief component 2, where the cover body 32 covers at least a part of the sealing element 31, the cover body 32 is placed in a second position, and a limiting portion 322 of the cover body 32 is staggered, along a circumference of the first through-hole 21, from an accommodation portion 23 located on a side that is of the shell 410′ and that is away from an interior of the shell 410′; and
Step S102B: Rotating the cover body 32 from the second position to a first position, so that the limiting portion 322 enters the accommodation portion 23 to restrict the cover body 32 from detaching from the pressure relief component 2.
Step S102B is performed after S102A, and these two steps are not shown in the drawing. In this embodiment, the limiting portion 322 is in fit with the accommodation portion 23 through rotation of the cover body 32, which is simple and quick. This can improve the assembling efficiency of the closing component 3 during assembling of the battery cell 400, and in turn, improve production efficiency of the battery cell 400.
In some embodiments, as shown in
Step S103: Rotating the cover body 32 from the first position to the second position, so that the limiting portion 322 is staggered from the accommodation portion 23 along the circumference of the first through-hole 21; and
Step S104: Detaching the cover body 32 from the pressure relief component 2.
The conventional method of closing the injection hole by laser welding does not allow electrolyte refilling for the battery. Through steps S103 and S104, this disclosure can implement flexible and convenient detachment of the cover body 32. Therefore, when the electrolytic solution is deficient or deteriorated, the closing component 3 is conveniently detachable for electrolyte refilling or degassing in the battery cell 400. After completion of the injection, the cover body 32 is mounted through steps S102A and S102B, so as to close the first through-hole 21. Through the electrolyte refilling, this disclosure improves the service life of the battery cell 400.
The electrolyte injection method can flexibly and conveniently implement repeated detachment and attachment of the closing component 3, and can reliably close the first through-hole 21 after completion of the electrolyte refilling, thereby ensuring reliability of the battery cell 400 in use after the electrolyte refilling, and keeping the appearance of the battery cell 400 the same as before the electrolyte refilling. In addition, the maintenance time can be shortened during the electrolyte refilling, and the battery cell 400 can be refilled with the electrolytic solution in time in the case of performance deterioration, so as to ensure relatively high working performance of the battery cell 400.
In some embodiments, the electrolyte injection method according to this disclosure further includes:
assisting, during closing of the first through-hole 21, in positioning the pressure relief component 2 through a positioning hole 226 located on an outer surface of the pressure relief component 2.
In this embodiment, during assembling of the battery cell 400 or electrolyte refilling, tooling may be inserted into the positioning hole 226 to provide a clamping force for the pressure relief component 2, so as to reduce the external force received by the pressure relief component 2 along the thickness or circumference of the pressure relief component 2, prevent the pressure relief component 2 from being stressed at the actuation mechanism or fragile structure, and improve the structural stability of the pressure relief component 2.
As shown in
Compared with the conventional method of closing the injection hole by laser welding, this disclosure not only avoids the welding step, but also avoids a plurality of steps such as cleaning up the weld-induced welding spatters and drying the liquid that remains after the cleaning. With this device, the battery cell 400 can be manufactured simply and efficiently, thereby improving the assembling efficiency of the battery cell 400.
The patentable subject-matters of this disclosure and features in different embodiments can make reference to each other. To the extent that no structural conflict occurs, a person skilled in the art may combine the technical features in different embodiments flexibly to form more embodiments.
The battery cell end cap assembly, the battery cell, and the electrical device according to this disclosure have been described in detail above. The principles and implementations of this disclosure have been described herein by using specific embodiments. The description of the embodiments is merely intended to help understand the methods and core ideas of this disclosure. It is hereby noted that various improvements and refinements, which may be made by a person of ordinary skill in the art without departing from the principles of this disclosure, fall within the protection scope of the claims of this disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202010991769.X | Sep 2020 | CN | national |
This application is a continuation of International Application PCT/CN2021/112790, filed on Aug. 16, 2021, which claims priority to Chinese Patent Application No. 202010991769.X, filed on Sep. 21, 2020 and entitled “END CAP ASSEMBLY, BATTERY CELL, BATTERY, AND ELECTRICAL DEVICE”, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2021/112790 | Aug 2021 | WO |
| Child | 18069237 | US |
