The present application relates to a nozzle assembly, a distribution system, an electrode sheet strip and an electrode.
Electric vehicles (EV) are a development direction of current automobile technology. An endurance is an important parameter to characterize the performance of electric vehicles. The endurance is largely determined by the performance of the EV battery. Lithium-ion batteries such as so-called chip batteries are a very important direction of battery research. Typically, lithium-ion batteries for electric vehicles, especially chip batteries, have an aluminum casing inside which the cells are housed. Multiple lithium-ion batteries are placed side by side to form a battery pack. Lithium-ion batteries need to be insulated while pursuing the possible lowest coating weight.
Furthermore, under normal circumstances, when a lithium battery is being charged, lithium ions are deintercalated from the positive electrode and then intercalated into the negative electrode; however, under abnormal conditions such as overcharge, low temperature or high current, the lithium ions deintercalated from the positive electrode will be abnormally intercalated in the negative electrode. In this case, lithium ions can only be precipitated on the surface of the negative electrode. This is known as lithium precipitation. If the phenomenon of lithium precipitation occurs, lithium ions will be reduced to metal lithium in different forms on the surface of the negative electrode, one of which is called lithium dendrite, which will continue to grow like a tree branch with the progress of the phenomenon of lithium precipitation, and this process is irreversible; and when lithium dendrites grows to a certain length, it will break through the diaphragm between the positive and negative electrodes, resulting in an internal short circuit of the cell, which is very likely to cause thermal runaway or even an explosion, which is very dangerous.
Accordingly, a very thin adhesive material needs to be coated on the surface of the battery. Generally, it is required to be able to evenly coat the thermal adhesive material larger than 10 mm (width) and less than 20 μm (thickness) on the electrode sheet of the battery, which is very important for improving the reliability of automobile batteries. The hot glue must be extremely thin and evenly coated on the surface of the electrode sheet. Also, electrode segments for forming electrodes are usually formed by cutting the electrode sheet, and the outer edges of the electrode sheet also need to be protected before cutting, especially during slitting the electrode sheet to form the electrode segments. This is obviously a serious challenge to existing coating products. Current methods and products have difficulty in achieving a uniform coating thickness of less than 20 μm on the electrode sheet and applying glue to the entire surface of the cathode segment used to form the cathode.
Thus, there is a need for improving the coating equipment or dispensing system, as well as glue dispensing methods.
An aspect of the present disclosure is to provide a nozzle assembly, which can apply fluid such as glue, especially polyurethane liquid glue, with high precision, so as to realize an extremely thin glue layer. Further, the disclosure also provides a distribution system, an electrode sheet strip and an electrode.
According to the present disclosure, there is provided a nozzle assembly, which is characterized by comprising: a lip member configured to have an annular body portion and a dam member at the center, the dam member extending from a bottom edge of a rectangular space surrounded by the body portion toward a top edge such that a rectangular opening is formed between a top edge of the dam member and the top edge of the rectangular space, the dam member extending an entire width of the rectangular opening in a transverse direction of the lip member, the rectangular opening being adapted to receive a fluid; and a cover plate configured to be connected to the lip member, wherein the dam member is recessed relative to a surface of the lip member connected to the cover plate so that a reservoir is formed between the cover plate and the dam member, the reservoir being in fluid communication with the rectangular opening, and a recess is provided on one of two surfaces of the cover plate and the lip member facing each other, the recess being in fluid communication with the reservoir so that the fluid can flow out from the reservoir through the recess in a strip shape.
In this way, the thickness and width of the fluid dispensed from the recess can be precisely and stably controlled so that a desired thickness, especially an extremely thin coating can be obtained on the substrate/workpiece.
Preferably, the recess is provided on a surface of the lip member facing the cover plate. As a result, the recess can be produced in a simple and efficient manner. And, preferably, in the transverse direction, a width of the recess is less than or equal to a width of the dam member, so that fluid can flow out from the space uniformly through the recess in a strip shape.
Preferably, the recess has a consistent depth with respect to the surface on which the recess is provided, and the recess is recessed by 50 to 150 μm with respect to the surface on which the recess is provided. Thus, an extremely thin adhesive layer can be coated on the surface of the substrate.
Preferably, the dam member is recessed with respect to a surface on a side of the lip member opposite to the cover plate.
Preferably, a boss is provided on an outer edge of a side of the lip member connected to a seal, for limiting the movement of the seal.
Preferably, a guide boss is provided on a bottom surface of the cover plate and/or a bottom surface of the lip member.
Preferably, the cover plate and the lip member are fixed together by screws in this order. Thereby, simple assembly can be realized.
According to the present disclosure, there is also provided a dispensing system characterized by comprising: a fluid supply assembly; a metering assembly in a form of a volumetric cavity pump and configured to be in fluid communication with the fluid supply assembly to receive a fluid from the fluid supply assembly; and a nozzle assembly in fluid communication with the metering assembly to receive the fluid from the metering assembly, wherein the nozzle assembly is a nozzle assembly described above.
Preferably, the fluid supply assembly includes a feeding container. The feeding container is configured to accommodate a fluid cartridge or to be connected with a pipe for supplying the fluid.
Preferably, the metering assembly includes a driving gear and a driven gear. The driving gear is driven by a motor.
Preferably, the metering assembly includes: a top plate having a top plate flow passage for receiving the fluid from the fluid supply assembly; a bottom plate having a bottom plate flow passage in fluid communication with a rectangular opening of the nozzle assembly; and a gear support plate located between the top plate and the bottom plate and having an aperture at the center for accommodating the driving gear and the driven gear.
Preferably, respective gear shafts of the driving gear and the driven gear are inserted into corresponding bores of the bottom plate to provide positioning of the gear shafts.
Preferably, a clearance between the driving gear and the driven gear on one side of the metering assembly is in fluid communication with the top plate flow passage of the top plate, and a clearance between the driving gear and the driven gear on the other side of the metering assembly is in fluid communication with the bottom plate flow passage of the bottom plate.
Preferably, a sealing member is provided between the gear support plate and the bottom plate, the sealing member surrounding an aperture in the gear support plate.
Preferably, the lip member of the nozzle assembly is connected to the bottom plate such that the top edge of the dam member is higher than the outlet of the bottom plate flow passage.
Preferably, a seal is provided between the lip member and the bottom plate, the seal having a rectangular central opening. A width of the central opening is greater than or equal to a width of the rectangular opening, and a height of the central opening is greater than or equal to a distance from the top edge of the rectangular opening to a bottom edge of the outlet of the bottom plate flow passage of the bottom plate.
Preferably, the bottom plate has a protrusion in which the outlet of the bottom plate flow passage of the bottom plate is arranged, the protrusion being adapted to be connected to the lip member.
The present application also relates to a method of dispensing a fluid onto a substrate having a thinner portion using said dispensing system, characterized in that said method comprises a step of dispensing a fluid onto the thin portion of the substrate using the dispensing system.
Preferably, the substrate is an electrode sheet for manufacturing an electrode of a battery, the electrode sheet having a thicker body portion and a thinner edge portion, the edge portion being located on a side of the body portion and continuous with the body portion, the method comprising a step of: dispensing the fluid onto a surface of the edge portion using the dispensing system, to produce an electrode sheet strip. The battery may be a chip battery.
Preferably, the method comprises: feeding the electrode sheet to a slitting machine, and slitting the edge portion along a slitting path using the slitting machine; and after the slitting, dispensing the fluid onto the surface of the edge portion using the dispensing system.
Preferably, the slitting machine starts slitting at a certain distance from a leading end of the electrode sheet, and ends the slitting at a certain distance from a trailing end of the electrode sheet.
Preferably, the edge portion of the electrode sheet is slit such that a width of a slit on the edge portion is suitable for the fluid from the dispensing system to completely penetrate the slit.
Preferably, the width of the slit is determined according to a thickness of the edge portion, a coating temperature of the fluid, and/or a sheet feeding speed.
Preferably, a slitting path is non-linear.
Preferably, the edge portion is slit to form a plurality of electrode ears along said slitting path. The electrode ears are preferably trapezoidal.
The present application also provides an electrode sheet strip for manufacturing an electrode of a battery, characterized in that: the electrode sheet strip is manufactured using the above method.
Preferably, the electrode sheet strip is cut into a plurality of sheet segments having the same shape along a width direction, and the plurality of sheet segments are laminated together to constitute the electrode.
The present application also provides an electrode, which is characterized in that the electrode is manufactured from the above electrode sheet strip.
Preferably, the electrode is an anode or a cathode of a battery.
The nozzle assembly and distribution system of the disclosure can realize an extremely thin glue thickness, for example, less than 20 μm, thereby meeting the spraying requirements on the surface of chip battery of electric vehicles. The method described in this application can glue the outer edge of the chip battery's electrode ears for protection.
These and other objects and advantages of the present disclosure will appear more fully from the following description taken in conjunction with the accompanying drawings, wherein the same reference numerals are used throughout the drawings to indicate the same or similar parts, and wherein:
Embodiments according to the present disclosure will be described in detail below with reference to the accompanying drawings. In the description of the drawings, the same or corresponding parts are denoted by the same numerals and symbols, and repeated descriptions will be omitted. In the following description, terms such as “up”, “down”, “front”, “rear”, “top” and “bottom” representing directions are only used to describe the drawings, and do not constitute a substantive limitation to the present disclosure.
The cover plate 6 is configured to be connected to the lip member 7. The front surface of the cover plate 6 is flat and the rear surface is intended to be connected with the lip member 7. The dam member 72 is recessed to a certain depth relative to the surface of the lip member 7 that is connected to the cover plate 6, that is, the front surface, so that a reservoir 721 is formed between the cover plate 6 and the dam member 72 (see
The recess 73 is recessed by 50 μm to 150 μm relative to the surface on which the recess 73 is provided. The recessed depth of the recess 73 is preferably uniform.
And, for example, as clearly shown in
The outer edge of the lip member 7 on the side opposite to the cover plate 6 is preferably provided with a boss 74 for receiving a sealing member and restricting the movement of the sealing member. The cover plate 6 and the lip member 7 are fixed together by screws, for example.
A thickness of the dam member 72 is not specifically limited here, and generally the thickness is smaller than the thickness of the lip member 7. The thickness of the dam member 72 and the recessed depth on both sides can be determined according to specific coating requirements. As shown in
The metering assembly 3 is an integrated metering system and is in the form of a volumetric cavity pump. The volumetric cavity pump can have a variety of configurations. The metering assembly 3 is configured to be in fluid communication with the feeding container 9 to receive fluid from the feeding container 9. As shown in
The metering assembly 3 also includes: a top plate 2 which has a top plate flow passage for receiving the fluid from the feeding container 9; a bottom plate 5 which has a bottom plate flow passage which is in fluid communication with the nozzle assembly 60, for example the rectangular opening 71 of the nozzle assembly 60; and a gear support plate 4 which is located between the top plate 2 and the bottom plate 5. The gear support plate 4 has an aperture at a central portion for receiving the driving gear 31 and the driven gear 32. That is, the micro gear set constituted by the driving gear 31 and the driven gear 32 is arranged in the gear support plate 4, thereby constituting an internal metering pump.
A clearance between the driving gear 31 and the driven gear 32 on one side of the metering assembly 3 is in fluid communication with the top plate flow passage of the top plate 2, and a clearance between the driving gear 31 and the driven gears 32 on the other side of the metering assembly 3 is in fluid communication with the bottom plate flow passage of the bottom plate 5. Fluid can thus flow from the top plate 2 via the gear set into the bottom plate 5.
Preferably, a seal is provided between the gear support plate 4 and the bottom plate 5, the seal surrounding the aperture in the gear support plate 4. The lip member 7 of the nozzle assembly 60 is attached to the bottom plate 5 such that the top edge of the dam member 72 is higher than the outlet of the bottom plate flow passage.
Thus, with the metering pump, fluid such as hot glue can be accurately and adequately delivered to the nozzle assembly. Specifically, the inner space of the metering pump, that is, the metering assembly 3, is in fluid communication with the feeding container 9, so as to be able to receive fluid material from the feeding container 9. The nozzle assembly 60 is in fluid communication with the metering assembly 3 so as to be able to receive fluid material from the metering assembly 3. The fluid material can sequentially pass through the fluid supply assembly, specifically the feeding container 9, the metering assembly 3, the opening 71 in the lip member 7, and then flow out of the nozzle assembly in an accurate amount through the recess 73 between the lip member 7 and the cover plate 6.
The feeding container 9 can be fixed together and in fluid communication with the metering assembly 3 in a number of ways. Preferably, the feeding container 9 is directly arranged on the top plate 2 of the metering assembly 3 and is in fluid communication with the top plate flow passage in the top plate 2. The drive device, such as a motor 1 for driving the metering assembly 3, and the feeding container 9 are arranged side by side on the top plate 2. Fluid material from the feeding container 9 flows into the metering assembly 3 via the top plate flow passage in the top plate 2.
A gear shaft 33 of the driving gear 31 and a gear shaft 34 of the driven gear 32 of the metering assembly 3 (with reference to
The dispensing system also includes a control assembly 11 to control the operation of the dispensing system. The control assembly 11 can be fixed to the housing of the feeding container 9, for example fixedly connected to the feeding container 9 on the side of the feeding container 9 opposite the motor 1.
The bottom plate 5 preferably has a sealing groove 51 on a top surface 55. A sealing groove corresponding to this sealing groove 51 is located on the bottom surface of the gear support plate 4. The sealing groove 51 and its corresponding sealing groove form an accommodating space, within which a sealing member is arranged. The sealing member surrounds the inner space of the metering assembly 3 to achieve fluid tightness.
The lip member 7 of the nozzle assembly 60 may be directly connected to the bottom plate 5 of the metering assembly 3 such that the top edge of the dam member 72 is higher than the outlet of the horizontal flow passage 53 and the opening 71 is in fluid communication with the outlet of the horizontal flow passage 53. Said opening 71 is in fluid communication with the horizontal flow passage 53 via a reservoir 722 (see
Preferably, a seal 8 is provided between the lip member 7 and the bottom plate 5. In the case where the sealing member 8 is provided, the depth of the reservoir 722 may be zero. The seal 8 has a central opening 81 which is substantially rectangular in shape. The main dimensions of the central opening 81 and the rectangular opening 71 are different from each other. Specifically, a width of the central opening 81 is greater than or equal to a width of the rectangular opening 71, and a height of the central opening 81 is greater than or equal to a distance between the top edge of the rectangular opening 71 and the bottom edge of the outlet of the horizontal flow passage 53 of the bottom plate 5. Both the lip member 7 and the cover plate 6 can be fixed to the bottom plate 5 via screws through the seal 8. Preferably, the screws pass through corresponding screw holes on the cover plate 6, the lip member 7, the seal 8 and the bottom plate 5 sequentially from one side of the cover plate 6, thereby connecting and fixing these components together.
In a working state, fluid such as liquid glue from the horizontal flow passage 53 of the bottom plate 5 first reaches the back side of the dam member 72 and is blocked by the back side. The liquid glue then rises along this back side of the dam member 72, and as the liquid glue rises to the top edge of the dam member 72, the liquid glue begins to pass over the top edge of the dam member 72, through the opening 71, into the space between the cover plate 6 and the lip member 7, namely the reservoir 721, and finally flows out of the nozzle assembly through the recess 73. The flow path of the fluid material is generally indicated by the arrows in
Preferably, the bottom edge of the reservoir 722 is aligned with or has the same height as the bottom edge of the outlet of the horizontal flow passage 53 of the bottom plate 5.
The various components of the dispensing system may be formed from the same material. Preferably, each component can be made of aluminum alloy. In addition, lightening holes can be provided on the components to reduce the overall weight of the system.
The assembly of the dispensing system of the present disclosure is described below. A distribution system can be divided into a plurality of subsystems, and the distribution system is obtained by assembling these subsystems. First, the lip member 7 and the cover plate 6 are fixed together with screws to form the nozzle assembly 60, that is, the first subsystem; the gear set, the gear support plate 4, the bottom plate 5 and the top plate 2 are fixed together to form the metering assembly 3, that is, the second subsystem; the fluid supply assembly that includes the feeding container 9 is assembled to form the third subsystem; the first to third subsystem groups are assembled together; and the driving device such as the motor 1 is assembled on the metering assembly 3, thereby forming the entire distribution system. It is easy to understand that the above assembly steps are not fixed, but can be freely changed in a suitable manner.
The operating principle of the dispensing system of the present disclosure is described below.
When the control assembly 11 issues a start command and the dispensing system is started, the fluid flowing from the fluid tank or hose enters the feeding container 9 of the fluid supply assembly. Fluid, such as liquid glue, enters the flow passage of the top plate 2 of the metering assembly 3 and then enters the inlet side clearance of the gear set. Driven by the motor 1, the fluid is fed by the gear set of the metering assembly 3 into the outlet-side clearance of the gear set and thus enters the bottom plate 5. Liquid glue flowing out from the bottom plate 5 passes through the seal 8 and is blocked by the dam member 72 of the lip member 7 to rise. The fluid then passes over the dam member 72, through the opening 71, into the reservoir 721 between the cover plate 6 and the lip member 7, and finally exits the nozzle assembly via the recess 73 in the form of a slot for distribution onto the surface of a workpiece or substrate such as a battery. Thus, the dispensing system utilizes a slit nozzle or a nozzle scraper to distribute an extremely thin liquid glue with a predetermined width on the target substrate. The dispensing system of the present disclosure may also be referred to as a band applicator incorporating a uniquely designed slot spraying assembly or nozzle assembly.
From the perspective of fluid flow path and working principle, the design idea of the nozzle assembly and/or distribution system of the present disclosure is obviously different from any previous design of the slit coating nozzle. The distribution system of the disclosure integrates a precision metering pump and a slot nozzle, which realizes high-precision coating performance, provides a variety of hot liquid glue supplies, provides various types of liquid glue patterns, and provides friendly human-machine interface interaction, reliable and durable spare parts, and easy maintenance. In addition, the distribution system of the present disclosure supports high-speed production lines of automated production lines.
The dispensing system of the present disclosure is suitable for coating the surface of chip batteries, electrode sheets used for manufacturing electrodes of chip batteries, and the like. The chip battery is preferably a battery for powering an electric vehicle. The power battery of an electric vehicle usually takes the form of a lithium-ion battery. Typically, the cathode of a lithium ion battery is made of aluminum sheet and the anode is made of copper sheet.
In the prior art, as mentioned above, before slitting, the body portion 101 is coated with a coating, and the edge portion 102 can be pasted with a layer of adhesive tape to protect the entire electrode sheet 10. After slitting, the resulting ears remain partially exposed, for example at least the outer edges of the ears 1021 are exposed, and in this state the electrodes of the battery cells are formed. In working condition, the electrode is directly immersed in the electrolyte. As a result, the produced battery may be short-circuited and thus cause a fire. This poses a great security risk.
In order to solve this problem, it is necessary to coat the entire surface of the electrode sheet, especially the edges including the ears, and considering the requirement for a lower coating mass ratio, it is necessary to coat the surface of the electrode sheet with a layer of very thin coating. For example, a new conductive glue that mixes electrode material with conductive binder has been produced. The glue is coated in a very thin layer on the edge of the electrode sheet to provide protection while the electrodes conduct electricity. The thickness of the coating or primer must be strictly controlled. The thickness needs to be controlled to be less than 30 μm, preferably less than 20 μm. The nozzle assembly and the dispensing system incorporating it according to the present disclosure can solve the above-mentioned problems by allowing the recess 73 of the nozzle assembly to have an extremely small recessed depth to dispense an extremely thin layer of fluid.
In particular, a method of dispensing a fluid on a substrate having a thinner portion using a dispensing system according to the disclosure is provided. The method includes the step of dispensing a fluid onto the thinner portion of the substrate using the dispensing system. Thereby, an extremely thin (less than 20 μm) fluid layer is obtained on the thinner portions. The substrate can be, for example, a sheet material used for producing electrodes of a chip battery.
However, with the dispensing system according to the present disclosure, it is possible to dispense a very thin layer of fluid on the edge portion 102 after slitting, thereby forming a very thin coating. The thickness of the coating is usually less than 20 μm. Due to the extremely thin coating, the coating mass is kept small while protecting the edge portion.
On the other hand, as shown in
Therefore, it is necessary to seal the outer edge of the electrode sheet strip 10′ with glue before the electrode sheet strip 10′ is further cut into sheet segments for forming final electrodes. That is to say, the electrode ears of the electrode sheet strip 10′ also need to be sufficiently protected before forming the sheet segments. If the slot-like outer edge of the electrode sheet strip is glued directly, the outer edge cannot be effectively glued directly along the entire corner because the outer edge is too thin.
However, with the present disclosure, a completely new type of sheet slitting and sizing edge sealing process is provided, wherein the fluid dispensing step is carried out immediately once the electrode sheet is slit. Specifically, as shown in
The existing slitting process directly uses a laser to continuously cut the electrode sheet in the shape of the electrode ear. According to the disclosure, a brand-new electrode ear slitting and coating process is provided, especially the edge-sealing process, which can provide a new battery cell manufacturing technology, which can increase the energy of electric vehicle batteries density and reduce safety risks. The technology described in this application is to add a dispensing system such as a dispensing nozzle/head in the slitting process. According to the new process requirements, it not only realizes a very thin special glue such as conductive glue on the sheet surface of the electrode ear, but also the outer edge of the electrode sheet strip obtained after slitting is protected by edge sealing, such as coating.
In the solution of the disclosure, a new glue of mixed electrode material and conductive adhesive is formed in a specific way. The glue conducts electricity and is coated in a very thin layer on the surface of the electrode sheet. By using the distribution system and the nozzle assembly of the disclosure, the coating thickness can be controlled between 20-30 μm or even thinner. As a result, a low coating quality is achieved while effectively protecting the electrode ears.
As shown in
The size of the slit 1023 of the sheet can be optimized according to actual needs, so as to obtain the best edge sealing effect. For example, the size of the slit 1023 may be determined according to the thickness of the edge portion, the coating temperature of the fluid, the sheet feeding speed, and the like. The distribution system can be mounted directly on the slitting machine or separately in front of the slitting machine in an advance direction of sheet. Thereby, the sheet can be subjected to coating on the surface as well as on the sides after slitting. This provides a brand-new method for coating the outer edge of the electrode ear of the electrode sheet of the lithium-ion battery, which is completely different from the existing coating method.
Alternatively, the nozzle assembly and/or dispensing system according to the present disclosure can be used for coating treatment directly on the electrode sheet strip shown in
Furthermore, at the step portion 103 between the body portion 101 and the edge portion 102 of the sheet, it is possible to perform a separate coating process to protect the surface of the step portion. Thereby, the use of adhesive tape is avoided. Moreover, the width of the nozzle edge of the nozzle assembly can be selected and kept constant, so that when the fluid is dispensed onto the substrate, the coating width can be kept consistent, and by setting/selecting the recessing depth of the recess 73 of the nozzle assembly, a glue thickness of less than 30 μm, preferably 20 μm is achieved.
In this disclosure, a band-shaped coating distribution system combined with the improvement of the electrode sheet manufacturing process is obtained, which will provide the best equipment and technical solutions, not only accurately and consistently applying an extremely thin adhesive layer of less than 30 μm, preferably less than 20 μm in the electrode sheet used to manufacture sheet electrodes, but also completely sealing the outer edge of the sheet.
The disclosure also relates to an electrode sheet strip. The electrode sheet strip is obtained through the above-mentioned novel slitting and edge-sealing process. The disclosure also relates to an electrode of a chip battery, which includes a plurality of electrode segments, the electrode segments being manufactured from the electrode sheet strip obtained according to the above process. A plurality of electrode segments are laminated together to form the electrode. The disclosure also relates to a chip battery, which includes electrodes obtained by laminating the electrode segments obtained according to the above method. The performance and safety of electric vehicles equipped with such batteries can be greatly improved.
Specific embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. It is anticipated that various changes and modifications may be made to the disclosure without departing from the spirit and scope of the disclosure as defined by the appended claims.
Number | Date | Country | Kind |
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202120793551.3 | Apr 2021 | CN | national |
This application is a National Phase application of International Patent Application No. PCT/CN2022/087132, filed Apr. 15, 2022, which claims priority to Chinese Patent Application No. 202120793551.3, filed Apr. 16, 2021, the entire disclosures of both of which are hereby incorporated by reference as if set forth in their entirety herein.
Filing Document | Filing Date | Country | Kind |
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PCT/CN2022/087132 | 4/15/2022 | WO |