Patent Application
20250201899
The present specification relates to an electrode assembly, in which a positive electrode, a negative electrode, and a separator provided between the positive electrode and the negative electrode are stacked and wound, a secondary battery including the same, a battery pack, and a transportation means.
In the case of a cylindrical battery, a jelly-roll type electrode assembly is manufactured by winding a long electrode, which is a predetermined width, in the form of a roll. The electrodes of the cylindrical battery, which is manufactured by inserting the jelly-roll type electrode assembly into a battery casing, are repeatedly contracted and expanded during a charging or discharging process. In particular, in case that tabs are positioned in a core of the jelly-roll type electrode assembly or a silicon-based active material is added into the negative electrode and a degree to which the electrode assembly is contracted or expanded is increased, a pressure applied to a mandrel of the electrode assembly is greatly increased.
Recently, with the increase in use of low-resistance/high-capacity designs, there has been an increasing number of cases in which the jelly-roll type electrode assembly includes the plurality of tabs or the silicon-based active material is added. Therefore, there is an increasing likelihood that the electrode assembly positioned at the mandrel side is deformed by the contraction or expansion of the electrode assembly. In particular, in case that a separator positioned between a negative electrode and a positive electrode is damaged, the negative electrode and the positive electrode come into direct contact with each other, which causes an internal short circuit that leads to a problem of heat generation and ignition.
In order to prevent the problem of the occurrence of damage to the separator and the internal short circuit caused by the deformation of the electrode assembly, there is a need to develop a technology capable of protecting the positive electrode and the separator in the corresponding region and suppressing the occurrence of the internal short circuit.
The present specification has been made in an effort to provide an electrode assembly, in which a positive electrode, a negative electrode, and a separator provided between the positive electrode and the negative electrode are stacked and wound, a secondary battery including the same, a battery pack, and a transportation means.
An embodiment of the present specification provides an electrode assembly in which a positive electrode, a negative electrode, and separators provided between the positive electrode and the negative electrode are stacked and wound, in which the negative electrode includes a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector, in which the negative electrode includes a negative electrode coated portion provided on the negative electrode current collector and having a negative electrode active material layer, and a negative electrode non-coated portion provided at one end of a mandrel part side of the negative electrode current collector and having no negative electrode active material layer, in which the separator and the negative electrode extend toward a mandrel part side of the electrode assembly so as to be further elongated than a longitudinal end of the positive electrode and are additionally wound, and in which a distance between a winding start portion of the negative electrode coated portion and the winding start portion of the positive electrode in a winding direction of the electrode assembly around a mandrel is 2-times winding length or more.
Another embodiment of the present specification provides an electrode assembly in which a positive electrode, a negative electrode, and separators provided between the positive electrode and the negative electrode are stacked and wound, in which the negative electrode includes a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector, in which the negative electrode includes a negative electrode coated portion provided on the negative electrode current collector and having a negative electrode active material layer, and a negative electrode non-coated portion provided at one end of a mandrel part side of the negative electrode current collector and having no negative electrode active material layer, in which the separator and the negative electrode extend toward a mandrel part side of the electrode assembly so as to be further elongated than a winding start portion of the positive electrode and are additionally wound, and in which on at least one cross-section of the electrode assembly in a direction perpendicular to a mandrel axis, a straight line, which extends from a mandrel to a winding start portion of the positive electrode may pass through two or more layers of the negative electrode coated portion.
In another embodiment of the present specification, the electrode assembly may further include a negative electrode tab provided on the negative electrode non-coated portion.
In another embodiment of the present specification, the electrode assembly may further include an adhesive tape provided on the negative electrode tab and the negative electrode current collector positioned at the periphery of the negative electrode tab. The adhesive tape may extend to the winding start portion of the negative electrode coated portion.
In another embodiment of the present specification, the electrode assembly may further include an additional adhesive tape provided on a surface opposite to the surface of the negative electrode current collector on which the negative electrode tab is provided so that the additional adhesive tape faces the adhesive tape. The additional adhesive tape may extend to the winding start portion of the negative electrode coated portion.
According to another embodiment of the present specification, on at least one cross-section of the electrode assembly in the direction perpendicular to the mandrel axis, the mandrel of the electrode assembly may be a center of a circle, and on an arbitrary circle having a radius that is a distance from the center of the circle to the winding start portion of the positive electrode, a central angle of a minor arc, which is formed to the winding start portion of the positive electrode from a contact point at which a line extending from the winding start portion of the negative electrode tab to an arbitrary point on a circumference of the arbitrary circle is orthogonal to a tangent line to the arbitrary circle, may be 90 degrees or less. Specifically, the central angle of the minor arc formed from the contact point to the winding start portion of the positive electrode may be 90° or less, 85° or less, 80° or less, 75° or less, 70° or less, 65° or less, 60° or less, 55° or less, 50° or less, 45° or less, 40° or less, 35° or less, 30° or less, 25° or less, 20° or less, 15° or less, 10° or less, or 5° or less and 0° or more, more than 0°, 1° or more, 2° or more, 3° or more, or 4° or more.
In still another embodiment of the present specification, the positive electrode may include a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector, the positive electrode may include a positive electrode non-coated portion having no positive electrode active material layer, a positive electrode tab may be provided on the positive electrode non-coated portion, and on the arbitrary circle, a central angle of a minor arc, which is formed to the winding start portion of the positive electrode from a contact point at which a line extending from the winding start portion of the positive electrode tab to an arbitrary point on a circumference of the arbitrary circle is orthogonal to a tangent line to the arbitrary circle, may be more than 90 degrees and 180 degrees or less.
In another embodiment of the present specification, the positive electrode may include a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector, the positive electrode may include two positive electrode coated portions having positive electrode active material layers and spaced apart from each other, and a positive electrode non-coated portion provided between the two positive electrode coated portion, and a positive electrode tab may be provided on the positive electrode non-coated portion.
In another embodiment of the present specification, the negative electrode may further include an additional negative electrode non-coated portion provided at one end of the outer peripheral side of the negative electrode current collector and having no negative electrode active material layer, and an additional negative electrode tab may be provided on the additional negative electrode non-coated portion.
In another embodiment of the present specification, the positive electrode may include a positive electrode current collector and positive electrode active material layers provided on two opposite surfaces of the positive electrode current collector, and winding start portions of the positive electrode active material layers provided on the two opposite surfaces of the positive electrode current collector are identical to or different from each other, particularly identical to each other.
In another embodiment of the present specification, the positive electrode may include positive electrode active material layers provided on two opposite surfaces of the positive electrode current collector, and winding end points of the positive electrode active material layers provided on the two opposite surfaces of the positive electrode current collector may be identical to or different from each other, and particularly identical to each other.
In another embodiment of the present specification, a length of the negative electrode tab may be 2 mm or more and 5 mm or less in the winding direction.
In another embodiment of the present specification, the separators may include a first separator and a second separator, and the electrode assembly may be made by sequentially stacking and winding the negative electrode, the first separator, the positive electrode, and the second separator.
In another embodiment of the present specification, the electrode assembly may be wound so that the negative electrode is disposed on an outermost periphery.
Yet another embodiment of the present specification provides a secondary battery including the electrode assembly and a battery case configured to accommodate the electrode assembly. In addition, a cross-section of the electrode assembly perpendicular to the mandrel axis may be a circle, and the battery case may have a cylindrical shape.
Another embodiment of the present specification provides a battery pack including two or more secondary batteries.
Still another embodiment of the present specification provides a transportation means including the battery pack. The transportation means may mean any means that works while moving or moving goods, people, and the like. The transportation means may be a bicycle, heavy equipment, agricultural equipment, vehicle, bus, airplane, or the like.
According to the electrode assembly according to the embodiment of the present specification, the negative electrode coated portion is provided by two turns or more at the core side in comparison with the winding start portion of the positive electrode, which may suppress a slip of the end of the positive electrode during the process of charging or discharging the battery.
According to the electrode assembly according to the embodiment of the present specification, the negative electrode tab is disposed rearward of the winding start portion of the positive electrode in the winding direction of the positive electrode, which may suppress a slip of the end of the positive electrode during the process of charging or discharging the battery.
The electrode assembly according to another embodiment of the present specification may be provided to prevent damage to the separator caused by the deformation of the electrode assembly caused by the contraction/expansion of the electrode during the process of charging or discharging the battery and prevent an internal short circuit between the electrodes, which may improve the stability and lifespan properties of the battery.
According to the electrode assembly according to still another embodiment of the present specification, the negative electrode tab is disposed rearward of the winding start portion of the positive electrode in the winding direction of the positive electrode, which may properly maintain the shape of the mandrel part during the process of charging or discharging the battery.
Hereinafter, the present invention will be described in detail with reference to the drawings. However, the drawings are intended to illustratively describe the present invention, and the scope of the present invention is not limited by the drawings.
The second separator 132, the positive electrode 120, the first separator 131, and the negative electrode 110 may be sequentially stacked and wound toward the negative electrode 110 in the winding direction. In case that the winding process is performed as described above, the separator of the wound electrode assembly may be exposed to an outermost periphery 1b.
As necessary, as illustrated in
An interior 1c of an wound electrode assembly 1 as illustrated in
In addition, it can be seen that a length of the electrode assembly 1, which is wound once from the mandrel 10, gradually increases to the outer periphery 1b. Specifically, a winding length for winding the electrode assembly once gradually increases from the mandrel 10 to the outer periphery 1b, and a periphery of the wound electrode assembly 1 increases. A first winding length (the first turn) primarily wound from a winding start point of the mandrel 10, a second winding length (the second turn) secondarily wound, a third winding length (the third turn) tertiarily wound, and the like may be sequentially connected to the outer periphery 1b.
A winding roll having the top plan view illustrated in
The positive electrode 120 and the negative electrode 110 may each include a current collector, and an active material layer provided on at least one surface of the current collector.
The positive electrode 120 may include a positive electrode current collector 121 and positive electrode active material layers 122 and 123 provided on at least one surface of the positive electrode current collector 121. The positive electrode active material layers 122 and 123 may be provided on two opposite surfaces of the positive electrode current collector 121 and include a first positive electrode active material layer 122 provided on one surface of the positive electrode current collector 121, and a second positive electrode active material layer 123 provided on a surface opposite to one surface on which the first positive electrode active material layer 122 is provided.
The positive electrode 120 includes one or more positive electrode tabs, and the positive electrode tab is positioned on a positive electrode non-coated portion on which the positive electrode active material layers 122 and 123 are not provided.
In the embodiment, the positive electrode 120 may include a positive electrode coated portion on which a positive electrode active material layer is provided on the positive electrode current collector 121, and a positive electrode non-coated portion provided at a distal end of one side or two opposite sides of the positive electrode current collector 121 and having no positive electrode active material layer. In this case, the positive electrode tab may be positioned on the positive electrode non-coated portion positioned at the distal end of one side or two opposite sides of the positive electrode current collector 121, particularly positioned on the positive electrode non-coated portion at the distal end of one side.
In another embodiment, the positive electrode 120 may include a positive electrode non-coated portion provided at an outer peripheral side end of the positive electrode current collector 121 and having no positive electrode active material layer, and the positive electrode tab may be formed on the positive electrode non-coated portion.
In another embodiment, the positive electrode 120 may include two or more positive electrode coated portions provided on the positive electrode current collector 121, having positive electrode active material layers, and spaced apart from one another in a longitudinal direction, and a positive electrode non-coated portion provided between the two or more positive electrode coated portions and having no positive electrode active material layer. In this case, the positive electrode tab may be positioned on the positive electrode non-coated portion between the two or more positive electrode coated portions, particularly positioned on the positive electrode non-coated portion positioned between the two positive electrode coated portions. In this case, the distal ends of the two opposite sides of the positive electrode 120 may be formed as free edges having no positive electrode non-coated portion.
The positive electrode 120 may include the positive electrode current collector 121 and the positive electrode active material layers 122 and 123 provided on two opposite surfaces of the positive electrode current collector 121. The first positive electrode active material layer 122 provided on one surface of the positive electrode current collector 121 may be identical or different in length to or from the second positive electrode active material layer 123 provided on the other surface.
In another embodiment of the present specification, the positive electrode 120 may include the positive electrode current collector 121 and the positive electrode active material layers 122 and 123 provided on the two opposite surfaces of the positive electrode current collector 121, and winding start portions of the positive electrode active material layers 122 and 123 provided on the two opposite surfaces of the positive electrode current collector 121 may be identical to each other.
In another embodiment of the present specification, the positive electrode 120 may include the positive electrode active material layers 122 and 123 provided on the two opposite surfaces of the positive electrode current collector 121, and winding end portions of the positive electrode active material layers 122 and 123 provided on the two opposite surfaces of the positive electrode current collector 121 may be identical to each other.
The negative electrode 110 may include a negative electrode current collector 111 and negative electrode active material layers 112 and 113 provided on at least one surface of the negative electrode current collector 111. The negative electrode active material layers 112 and 113 may be provided on two opposite surfaces of the negative electrode current collector 111 and include a first negative electrode active material layer 112 provided on one surface of the negative electrode current collector 111, and a second negative electrode active material layer 113 provided on a surface opposite to one surface on which the first negative electrode active material layer 112 is provided.
The negative electrode 110 includes one or more negative electrode tabs 116, and the negative electrode tabs 116 are positioned on the negative electrode non-coated portions on which the negative electrode active material layers 112 and 113 are not provided.
In the embodiment, the negative electrode 110 may include a negative electrode coated portion on which a negative electrode active material layer is provided on the negative electrode current collector 111, and a negative electrode non-coated portion provided at a distal end of one side or two opposite sides of the negative electrode current collector 111 and having no negative electrode active material layer. In this case, the negative electrode tab 116 may be positioned on the negative electrode non-coated portion positioned at the distal end of one side or two opposite sides of the negative electrode current collector 111, particularly positioned on the negative electrode non-coated portion at the distal end of the two opposite sides.
In another embodiment, the negative electrode 110 may include a negative electrode non-coated portion positioned at an end of the mandrel part side of the negative electrode current collector 111 and having no active material layer, and the negative electrode tab 116 may be formed on the negative electrode non-coated portion.
The negative electrode 110 may include the negative electrode current collector 111 and the negative electrode active material layers 112 and 113 provided on two opposite surfaces of the negative electrode current collector 111. The first negative electrode active material layer 112 provided on one surface of the negative electrode current collector 111 may be identical or different in length to or from the second negative electrode active material layer 113 provided on the other surface.
In still another embodiment, the positive electrode 120 may include: two positive electrode coated portions spaced apart from each other in the winding direction of the electrode assembly 1 and having the positive electrode active material layers 122 and 123 on the positive electrode current collector 121; and a positive electrode non-coated portion provided between the two coated portion and having no positive electrode active material layer on the positive electrode current collector 121. One positive electrode tab may be formed on the positive electrode non-coated portion, and the negative electrode 110 may include two negative electrode non-coated portions provided at two opposite ends of the negative electrode current collector 111 and having no negative electrode active material layer. The negative electrode tabs 116 may be formed on the two negative electrode non-coated portions, one negative electrode tab for each negative electrode non-coated portion.
The embodiment of the present specification provides an electrode assembly in which a positive electrode, a negative electrode, and separators provided between the positive electrode and the negative electrode are stacked and wound, in which the negative electrode includes a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector, in which the negative electrode includes a negative electrode coated portion provided on the negative electrode current collector and having a negative electrode active material layer, and a negative electrode non-coated portion provided at one end of a mandrel part side of the negative electrode current collector and having no negative electrode active material layer, in which the separator and the negative electrode extend toward a mandrel part side of the electrode assembly so as to be further elongated than a longitudinal end of the mandrel part side of the positive electrode and are additionally wound, and in which on at least one cross-section of the electrode assembly in a direction perpendicular to a mandrel axis, a straight line, which extends from a mandrel to a winding start portion of the positive electrode may pass through two or more layers of the negative electrode coated portion. The straight line, which extends from the mandrel to the winding start portion of the positive electrode, may pass through two or more layers, three or more layers, four or more layers, or five or more layers of the negative electrode coated portion. As the number of layers of the negative electrode coated portion, through which the straight line, which extends from the mandrel to the winding start portion of the positive electrode, passes, increases, the internal rigidity of the mandrel part side, which suppresses the movement and slip of the winding start portion of the positive electrode, is increased.
In this case, the negative electrode non-coated portion having no negative electrode active material layer has a thickness that is a thickness of the negative electrode current collector. However, a thickness of the negative electrode coated portion is a sum of a thickness of the negative electrode current collector and a thickness of the negative electrode active material layer provided on at least one surface of the negative electrode current collector, i.e., 5 to 15 times the thickness of the negative electrode non-coated portion. In case that the negative electrode coated portion has the negative electrode active material layers provided on the two opposite surfaces of the negative electrode current collector, the thickness of the negative electrode coated portion is 9 to 15 times the thickness of the negative electrode non-coated portion. Therefore, the internal rigidity of the mandrel part side may be more quickly increased when the negative electrode coated portion has a relatively large thickness and is additionally wound than when the negative electrode non-coated portion is additionally wound before the positive electrode is wound.
Still another embodiment of the present specification provides an electrode assembly in which a distance between the winding start portion of the negative electrode coated portion and the winding start portion of the positive electrode in the winding direction from the mandrel of the electrode assembly is a length for winding 2 turns. As the distance between the winding start portion of the negative electrode coated portion and the winding start portion of the positive electrode increases, the length of the negative electrode coated portion, which does not correspond to the positive electrode coated portion at the mandrel part side, increases, such that the internal rigidity of the mandrel part side increases as the negative electrode coated portion, which does not correspond to the positive electrode coated portion at the mandrel part side, is wound around the mandrel part side twice or more.
In the present specification, the winding start portion may be expressed as a winding start point that is a single point.
In the present specification, a mandrel 10 illustrated in
The distance between the winding start portion of the negative electrode coated portion and the winding start portion of the positive electrode may be a length for winding 2 turns or longer, a length for winding 3 turns or longer, a length for winding 4 turns or longer, or a length for winding 5 turns or longer. As the length of the negative electrode coated portion, which does not correspond to the positive electrode coated portion, increases, the internal rigidity of the mandrel part side gradually increases, which may prevent the inside of the electrode from being collapsed by the repeated contraction and expansion of the electrode. As the length of the negative electrode coated portion, which does not correspond to the positive electrode coated portion, increases, a loss, which is not involved in a reaction, increases. Therefore, it is important to ensure appropriate rigidity, which prevents the collapse of the inside, with a minimum length, as necessary.
In another embodiment of the present specification, the electrode assembly may further include a negative electrode tab provided on the negative electrode non-coated portion.
In another embodiment of the present specification, the electrode assembly may further include an adhesive tape provided on the negative electrode tab and the negative electrode current collector positioned at the periphery of the negative electrode tab.
In another embodiment of the present specification, the adhesive tape may extend to the winding start portion of the negative electrode coated portion.
In another embodiment of the present specification, the electrode assembly may further include an additional adhesive tape provided on a surface opposite to the surface of the negative electrode current collector on which the negative electrode tab is provided so that the additional adhesive tape faces the adhesive tape.
In another embodiment of the present specification, the additional adhesive tape may extend to the winding start portion of the negative electrode coated portion.
Still another embodiment of the present specification provides an electrode assembly in which the mandrel of the electrode assembly 1 is a center of a circle, and on an arbitrary circle having a radius that is a distance from the center of the circle to the longitudinal end of the mandrel part side of the positive electrode 120, i.e., the winding start portion of the positive electrode 120, a central angle a of a minor arc, which is formed to the longitudinal end of the positive electrode 120 from a contact point at which a line extending from the winding start portion of the negative electrode tab 116 to an arbitrary point on a circumference of the arbitrary circle is orthogonal to a tangent line to the arbitrary circle, is 90° or less. Specifically, the central angle of the minor arc formed from the contact point to the longitudinal end of the positive electrode may be 90° or less, 85° or less, 80° or less, 75° or less, 70° or less, 65° or less, 60° or less, 55° or less, 50° or less, 45° or less, 40° or less, 35° or less, 30° or less, 25° or less, 20° or less, 15° or less, 10° or less, or 5° or less and 0° or more, more than 0°, 1° or more, 2° or more, 3° or more, or 4° or more. In this case, the winding start portion of the positive electrode 120 may be a winding start portion of the positive electrode coated portion having the positive electrode active material layers 122 and 123.
Still another embodiment of the present specification provides the electrode assembly 1 in which the positive electrode 120, the negative electrode 110, and the separators 131 and 132 provided between the positive electrode 120 and the negative electrode 110 are stacked and wound, the negative electrode 110 includes the negative electrode current collector 111 and the negative electrode active material layers 112 and 113 provided on at least one surface of the negative electrode current collector 111, and the negative electrode 110 includes the negative electrode tab 116 provided at one end of the mandrel part side of the negative electrode current collector 111. The separators 131 and 132 and the negative electrode 110 extend from the mandrel part side of the electrode assembly 1 so as to be further elongated than the longitudinal end of the positive electrode 120 and are additionally wound.
On at least one cross-section in the direction perpendicular to the mandrel of the electrode assembly 1, an angle θ1 defined between a straight line Lce extending from the mandrel to the longitudinal end of the mandrel part side of the positive electrode 120 and a straight line Lat extending from the mandrel to the winding start portion of the negative electrode tab 116 may be 90° or less. In this case, the angle θ1 is an angle from the straight line Lce to the straight line Lat in a counterclockwise direction, an angle from the straight line Lat to the straight line Lce in a clockwise direction, or an angle from the straight line Lce to the straight line Lat in the winding direction.
In other words, in
Because the negative electrode 110 further extends than the positive electrode 120 and is wound around the mandrel, the negative electrode tab 116 at the mandrel side is wound first before the winding start portion of the positive electrode is wound, and then the positive electrode 120 is wound. As illustrated in
In another embodiment of the present specification, a length of the negative electrode tab 116 may be 2 mm or more and 5 mm or less in the winding direction. In this case, the rigidity is imparted to suppress the motion of the mandrel part side of the positive electrode 120 by pressing the end of the mandrel part side of the positive electrode 120.
In another embodiment of the present specification, the negative electrode 110 may further include an additional negative electrode non-coated portion provided at one end of the outer peripheral side of the negative electrode current collector 111 and having no negative electrode active material layer, and an additional negative electrode tab may be provided on the additional negative electrode non-coated portion.
In another embodiment of the present specification, an angle θ2 defined between a straight line Lce extending from the mandrel to the longitudinal end of the mandrel part side of the positive electrode 120 and a straight line Lae extending from the mandrel to the winding start portion of the positive electrode tab (not illustrated) may be more than 90° and 180° or less. In this case, the angle θ2 is an angle from the straight line Lce to the straight line Lae in the counterclockwise direction, an angle from the straight line Lae to the straight line Lce in the clockwise direction, or an angle from the straight line Lce to the straight line Lae in the winding direction. In addition, the angle θ2 may be the central angle b of the arc formed to the longitudinal end of the mandrel part side of the positive electrode 120 from the contact point at which the line extending from the winding start portion of the positive electrode tab (not illustrated) to the arbitrary point on the circumference of the arbitrary circle is orthogonal to the tangent line to the arbitrary circle.
As illustrated in
Another embodiment of the present specification provides the secondary battery including the electrode assembly 1 and the battery case configured to accommodate the electrode assembly 1.
In the embodiment of the present specification, the secondary battery may be a battery having a ratio of a form factor that is about 0.4 or less (the ratio of the form factor is defined as a value made by dividing a diameter of the cylindrical battery by a height of the cylindrical battery, i.e., a ratio of a diameter @ to a height H). In this case, the form factor means a value indicating the diameter and the height of the cylindrical secondary battery. For example, 18650 cell, 21700 cell, and the like may be used. In the case of 18650 cell, a diameter thereof is approximately 18 mm, a height thereof is approximately 65 mm, and a ratio of the form factor thereof is approximately 0.277. In the case of 21700 cell, a diameter thereof is approximately 21 mm, a height thereof is approximately 70 mm, and a ratio of the form factor thereof is approximately 0.300.
In the embodiment of the present specification, the secondary battery may be a cylindrical secondary battery having a ratio of the form factor that is larger than 0.4.
The cylindrical secondary battery according to the embodiment of the present specification may be 46110 cell, 48750 cell, 48110 cell, 48800 cell, or 46800 cell. In the numerical value indicating the form factor, the first two numbers indicate a diameter of the cell, the next two numbers indicate a height of the cell, and the final number 0 indicates that a cross-section of the cell is circular.
The secondary battery according to the embodiment of the present specification may be a cylindrical secondary battery that is a cylindrical cell and has a diameter of 46 mm, a height of 110 mm, and a ratio of the form factor of 0.418.
The secondary battery according to the embodiment of the present specification may be a cylindrical secondary battery that is a cylindrical cell and has a diameter of 48 mm, a height of 75 mm, and a ratio of the form factor of 0.640.
The secondary battery according to the embodiment of the present specification may be a cylindrical secondary battery that is a cylindrical cell and has a diameter of 48 mm, a height of 110 mm, and a ratio of the form factor of 0.436.
The secondary battery according to the embodiment of the present specification may be a cylindrical secondary battery that is a cylindrical cell and has a diameter of 48 mm, a height of 80 mm, and a ratio of the form factor of 0.600.
The secondary battery according to the embodiment of the present specification may be a cylindrical secondary battery that is a cylindrical cell and has a diameter of 46 mm, a height of 80 mm, and a ratio of the form factor of 0.575.
The can 21 may have a column structure having a space therein. The internal space of the can 21 may accommodate an electrolyte (not illustrated) and the battery assembly 1 including the electrode and the separator. The can 21 may have one side having an opened structure, and the other side having a sealed structure. In this case, one side and the other side of the can 21 may mean ends positioned on the upper and lower portions in the gravitational direction or along the central axis of the can 21.
The can 21 may be made of a lightweight conductive metallic material such as aluminum or aluminum alloy.
The cap assembly 22 may be coupled to an upper portion of the can 21 and include a top cap, a safety vent, and a current blocking element.
The top cap may protrude from an uppermost portion of the cap assembly 22 and serve as an electrode terminal electrically connected to an external component. The safety vent may discharge a high-pressure gas when the gas is generated at a predetermined level or higher because of an increase in internal pressure. The current blocking element may block an electric current when the internal pressure of the battery increases.
The top cap may be coupled to the upper portion of the can 21. That is, the top cap may be coupled to a crimping portion positioned on an uppermost portion of the can 21.
The secondary battery 20 according to the present invention may include a gasket between the crimping portion and the top cap. The gasket may increase sealability of the case.
The top cap may include a protruding portion protruding upward in the gravitational direction, a rim portion coupled to the gasket, and a connection portion configured to connect the protruding portion and the rim portion.
The safety vent may be positioned below the top cap and coupled to an end of the top cap. The safety vent is in contact with an end of the top cap by a predetermined length, and a portion, except for a contact length, may be positioned to be spaced apart from the top cap at a predetermined distance.
The safety vent may be bent one or more times. For example, two notches may be provided on a portion of the safety vent that is not in contact with the top cap. That is, the safety vent 12 may be bent by a notch, and a center of the safety vent may be recessed to define a recessed central portion. Further, the safety vent may have a venting portion that connects the recessed central portion and the end being in contact with the top cap.
The current blocking element may be positioned below the safety vent and be at least partially in contact with the safety vent.
The current blocking element may include a central portion protruding in a direction toward the safety vent, and a CID filter portion positioned outside the central portion. Therefore, a central portion of the current blocking element of the cap assembly 22 may be in contact with the recessed central portion of the safety vent.
The cap assembly 22 according to the present invention may have a CID gasket provided at an end of the CID filter portion. The CID gasket may prevent the safety vent from being in contact with a portion except for the central portion of the current blocking element.
Another embodiment of the present specification provides a battery pack including two or more secondary batteries.
Still another embodiment of the present specification provides a transportation means including the battery pack 200. The transportation means may mean any means that works while moving or moving goods, people, and the like. The transportation means may be a bicycle, heavy equipment, agricultural equipment, vehicle, bus, airplane, or the like.
The battery pack 200 may be mounted in a vehicle V. For example, the vehicle may be an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle V may be a four-wheel vehicle or a two-wheel vehicle.
With reference to
The present invention has been described with reference to the limited exemplary embodiments and the drawings, but the present invention is not limited thereto. The described exemplary embodiments may be changed or modified by those skilled in the art to which the present invention pertains within the technical spirit of the present invention and within the scope equivalent to the appended claims.
As illustrated in
The jelly-roll type assembly was inserted into the can (cross-sectional diameter: 21 mm) having the cylindrical shape. Next, the batteries of the example and the comparative example were completely manufactured by injecting a carbonate-based electrolyte into the cans and sealing the cans.
Whether the jelly rolls were deformed was observed after the batteries of the example and comparative example were charged and discharged once under the following condition.
To identify the deformation of the battery after a single charge and discharge, the XSCAN-8225 was used to take CT images at 225 kV and a frame rate of 3 fps, and the results are illustrated in
In the winding directions in Comparative Example 1 in
In Comparative Example 1 in
With reference to
With reference to
The deformation degree after the operation of the battery caused by the difference in arrangement of the tape illustrated in
With reference to
As illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0184825 | Dec 2022 | KR | national |
The present application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/KR2023/021567, filed on Dec. 26, 2023, which claims priority from Korean Patent Application No. 10-2022-0184825, filed on Dec. 26, 2022, the entire contents of all of which are hereby incorporated herein by reference herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2023/021567 | 12/26/2023 | WO |
