Battery cell and battery module

Abstract

The present application relates to the technical field of energy storage equipment, and particularly relates to a battery cell and a battery module. The battery cell comprises a pole group and a cover plate structure. The pole group has a first plane and a first protruding part at one end along a first direction. The first protruding part is arranged protruding along the first direction. The first plane is located at the root of one side of the first protruding part along a second direction. The first plane is provided with a tab. The first direction is perpendicular to the second direction. The cover plate structure comprises a top cover and a pole column assembly. The top cover has a second plane and a first groove. The second plane is located at the slot opening side of the first groove. The second plane is arranged corresponding to the first plane. The pole column assembly is arranged at the second plane. The pole column assembly is connected with the tab. The first protruding part is located in the first groove. The battery module comprises a plurality of the above battery cells. At least part of the battery cells are arranged in sequence along a third direction. The third direction is perpendicular to the first direction and the second direction. The battery cell and the battery module can help to improve the volumetric energy density of the battery cell and ensure the stability of the quality.

Description

Technical Field

[0001] This invention relates to the field of energy storage equipment technology, and in particular to a battery cell and battery module. Background Technology

[0002] A battery cell comprises an electrode assembly and a cell housing. The electrode assembly is housed within the cell housing, which typically includes a cover structure and a shell. The electrode post assemblies on the cover structure are electrically connected to the tabs of the electrode assembly. In existing technology, the cover structure of the battery cell is a flat plate. The lower plastic portion of the cover structure needs to have a protrusion facing the electrode assembly and pressing against the portion of the electrode assembly without tabs, thereby pressing the electrode assembly into the shell. This protrusion of the lower plastic portion occupies space within the shell, limiting the volumetric energy density of the battery cell. A certain gap needs to be maintained between the electrode assembly and the shell for insertion, but if the orientation of the battery cell changes or is subjected to stress, the electrode assembly may shift or move within the shell, affecting the stability of the battery cell's quality. Summary of the Invention

[0003] One object of the present invention is to provide a battery cell that can help improve the volumetric energy density of the battery cell and help prevent the electrode assembly from shifting within the casing, thereby ensuring the stability of the battery cell quality.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] A battery cell is provided, comprising:

[0006] A pole assembly, wherein one end of the pole assembly along a first direction has a first plane and a first protrusion, the first protrusion protrudes along the first direction, the first plane is located at the root of the first protrusion on one side along a second direction, and a tab is provided at the first plane, wherein the first direction is perpendicular to the second direction;

[0007] The cover plate structure includes a top cover and an electrode assembly. The top cover has a second plane and a first groove. The second plane is located at the edge of the groove opening of the first groove and is disposed corresponding to the first plane. The electrode assembly is disposed at the second plane and is connected to the electrode lug. The first protrusion is located in the first groove.

[0008] Optionally, along the second direction, the width of the pole group is A, satisfying: 80mm≤A≤290mm;

[0009] And / or, along a third direction, the thickness of the pole group is B, satisfying: 36mm≤B≤118mm, and the third direction is perpendicular to both the first direction and the second direction;

[0010] And / or, along the second direction, the width of the pole group is A, and the width of the first protruding end face of the first protrusion along the second direction is W, satisfying: 0.33≤W / A≤0.55;

[0011] And / or, along the first direction, the height of the first protrusion is H1, satisfying: 5mm≤H1≤15mm.

[0012] Optionally, the battery cell further includes a housing, the cover plate structure covering the opening of the housing to form a battery cell outer shell, and the electrode assembly disposed inside the battery cell outer shell;

[0013] The first sidewall of the pole group has a second protrusion, and the first sidewall is perpendicular to a third direction, which is perpendicular to both the first direction and the second direction.

[0014] The second sidewall of the housing has a second groove, which is provided corresponding to the first sidewall, and the second protrusion is located in the second groove.

[0015] Optionally, both the second protrusion and the second groove extend along the first direction, and one end of the second protrusion along the first direction has a third protrusion, which protrudes from the first plane. The cover plate structure has a third groove, and the third protrusion is located within the third groove.

[0016] Optionally, along the third direction, the width of the third protrusion is K, satisfying: 8mm≤K≤30mm;

[0017] And / or, the third protrusion is located on one side of the first plane along the third direction, the side of the third protrusion perpendicular to the second direction and facing away from the first protrusion is flush with the first side of the first plane, the first side is parallel to the third direction, the distance between the projection of the first protruding end face of the first protrusion toward the virtual extension surface of the first plane and the first side is L2, and the length of the third protrusion along the third direction is L1, satisfying: 0.45≤L2 / L1≤0.75.

[0018] Optionally, the first protruding end face of the first protrusion is flush with the end face of the third protrusion along the first direction;

[0019] And / or, the first protrusion is connected to the third protrusion;

[0020] And / or, the third sidewall of the pole group is perpendicular to the second direction, and one side of the second protrusion perpendicular to the second direction is flush with the third sidewall.

[0021] Optionally, the electrode assembly has two first planes at one end along the first direction, the two first planes being located at the root of the first protrusion on both sides along the second direction, and each of the two first planes has an electrode tab;

[0022] The two first sidewalls of the electrode assembly, which are arranged opposite each other along the third direction, each have a second protrusion, and each of the two second protrusions has a third protrusion. The third protrusion of one second protrusion is located on one side of a first plane along the third direction, and the third protrusion of the other second protrusion is located on the other side of a first plane along the third direction.

[0023] Optionally, along the third direction, the width of the first protrusion is E, and along the third direction, the thickness of the pole group is B, satisfying: 0.35≤E / B≤0.55;

[0024] And / or, the second side of the second protrusion is perpendicular to the second direction and faces the first protrusion, and along the second direction, the distance between the second side of the two second protrusions is L3, satisfying: 4mm≤L3≤18mm.

[0025] Optionally, the cross-section of the first protrusion perpendicular to the third direction is trapezoidal, the longer side of the trapezoid is closer to the first plane than the shorter side of the trapezoid, and the third direction is perpendicular to both the first direction and the second direction.

[0026] Another objective of this invention is to provide a battery module that helps to improve the volumetric energy density of the battery cell and helps to prevent the electrode assembly from shifting within the casing, thereby ensuring the stability of the battery cell quality.

[0027] To achieve this objective, the present invention adopts the following technical solution:

[0028] A battery module is provided, comprising a plurality of the above-described battery cells, at least some of which are arranged sequentially along a third direction, the third direction being perpendicular to both the first direction and the second direction.

[0029] The beneficial effects of this invention are:

[0030] This invention provides a battery cell, including an electrode assembly and a cover plate structure. The electrode assembly has a first plane and a first protrusion at one end along a first direction. The first protrusion protrudes along the first direction, and the first plane is located at the root of the first protrusion on one side along a second direction. A tab is located at the first plane, and the first direction is perpendicular to the second direction. The cover plate structure includes a top cover and a terminal assembly. The top cover has a second plane and a first groove. The second plane is located at the edge of the groove opening and corresponds to the first plane. The terminal assembly is located at the second plane and connected to the tab. The first protrusion is located within the first groove. The first protrusion of the electrode assembly cooperates with the first groove of the cover plate structure to prevent the electrode assembly from shifting along the second or third direction, ensuring the stability of the battery cell quality. Furthermore, during the process of inserting the electrode assembly into the housing, the bottom of the first groove can abut against the first protruding end face of the first protrusion, pressing the electrode assembly into the housing. This eliminates the need for a protrusion on the lower plastic to press against the electrode assembly, thus saving space occupied by the protrusion on the lower plastic and increasing the volumetric energy density of the battery cell.

[0031] The present invention also provides a battery module comprising a plurality of the aforementioned battery cells, at least some of which are arranged sequentially along a third direction, the third direction being perpendicular to both the first and second directions. This battery module helps to improve the volumetric energy density of the battery cells and helps to prevent the electrode assembly from shifting within the casing, ensuring the stability of the battery cell quality. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the battery cell structure provided in an embodiment of the present invention;

[0033] Figure 2 This is a cross-sectional view of the battery cell provided in an embodiment of the present invention;

[0034] Figure 3 This is a first-view structural schematic diagram of the pole group provided in an embodiment of the present invention;

[0035] Figure 4 This is a partially enlarged view of the pole group provided in an embodiment of the present invention from a first perspective;

[0036] Figure 5 This is a schematic diagram of the pole group provided in an embodiment of the present invention from a second perspective;

[0037] Figure 6 This is a partially enlarged view of the pole group provided in the embodiment of the present invention from a third perspective;

[0038] Figure 7 This is a schematic diagram of the top cover provided in an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the structure of the housing provided in an embodiment of the present invention.

[0040] In the picture:

[0041] 1. Pole assembly; 11. First plane; 111. First side; 12. First protrusion; 121. First protruding end face; 13. Pole lug; 14. First sidewall; 141. Second protrusion; 1411. Third protrusion; 14111. First side; 1412. Second side; 15. Third sidewall;

[0042] 2. Top cover; 21. Second plane; 22. First groove; 23. Third groove;

[0043] 3. Terminal assembly;

[0044] 4. Shell; 41. Second sidewall; 411. Second groove. Detailed Implementation

[0045] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings, not all of them.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0047] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0048] A battery cell comprises an electrode assembly and a cell housing. The electrode assembly is housed within the cell housing, which typically includes a cover structure and a shell. The electrode post assemblies on the cover structure are electrically connected to the tabs of the electrode assembly. In existing technology, the cover structure of the battery cell is a flat plate. The lower plastic portion of the cover structure needs to have a protrusion facing the electrode assembly and pressing against the portion of the electrode assembly without tabs, thereby pressing the electrode assembly into the shell. This protrusion of the lower plastic portion occupies space within the shell, limiting the volumetric energy density of the battery cell. A certain gap needs to be maintained between the electrode assembly and the shell for insertion, but if the orientation of the battery cell changes or is subjected to stress, the electrode assembly may shift or move within the shell, affecting the stability of the battery cell's quality.

[0049] Therefore, this embodiment provides a battery cell to solve the above problems. This battery cell can help improve the volumetric energy density of the battery cell and help prevent the electrode assembly 1 from shifting within the housing 4, thus ensuring the stability of the battery cell quality.

[0050] like Figures 1-8 As shown, the battery cell in this embodiment includes an electrode group 1 and a cover plate structure. Figure 3 In the diagram, direction ab is the first direction, direction cd is the second direction, and direction ef is the third direction. The first, second, and third directions are perpendicular to each other. Optionally, in this embodiment, the first direction is the length direction of the cell and electrode group 1 and the thickness direction of the cover plate structure; the second direction is the width direction of the cell and electrode group 1 and the length direction of the cover plate structure; and the third direction is the thickness direction of the cell and electrode group 1 and the width direction of the cover plate structure.

[0051] like Figure 3 As shown, the electrode assembly 1 has a first plane 11 and a first protrusion 12 at one end along the first direction. The first protrusion 12 protrudes along the first direction, and the first plane 11 is located at the root of the first protrusion 12 on one side along the second direction. An electrode lug 13 is located at the first plane 11, and the first direction is perpendicular to the second direction. The cover plate structure includes a top cover 2 and an electrode post assembly 3, as shown... Figure 7 As shown, the top cover 2 has a second plane 21 and a first groove 22. The second plane 21 is located at the edge of the groove opening of the first groove 22. The second plane 21 is set corresponding to the first plane 11. The pole post assembly 3 is set at the second plane 21. The pole post assembly 3 is connected to the pole ear 13. The first protrusion 12 is located in the first groove 22.

[0052] The first protrusion 12 of the electrode assembly 1 cooperates with the first groove 22 of the cover plate structure to prevent the electrode assembly 1 from shifting along the second or third direction, thus ensuring the stability of the cell quality. Furthermore, during the insertion of the electrode assembly 1 into the casing, the bottom of the first groove 22 abuts against the first protruding end face 121 of the first protrusion 12, pressing the electrode assembly 1 into the casing 4. This eliminates the need for a protrusion on the lower plastic to press against the electrode assembly 1, saving space occupied by the protrusion on the lower plastic and increasing the volumetric energy density of the cell.

[0053] Optionally, the battery cell also includes a housing 4, with a cover plate structure covering the opening of the housing 4 to form a battery cell outer shell, and the electrode assembly 1 disposed inside the battery cell outer shell. The first sidewall 14 of the electrode assembly 1 has a second protrusion 141, and the first sidewall 14 is perpendicular to a third direction, which is perpendicular to both the first and second directions. Figure 8 As shown, the second sidewall 41 of the housing 4 has a second groove 411, which corresponds to the first sidewall 14. The second protrusion 141 is located within the second groove 411. By providing the second protrusion 141 on the first sidewall 14 of the electrode assembly 1, the cooperation between the second protrusion 141 and the second groove 411 can further limit the mutual positioning between the electrode assembly 1 and the housing 4, which helps to prevent the electrode assembly 1 from shifting during subsequent use. Optionally, the second protrusion 141 protrudes along a third direction, the second groove 411 extends along a third direction, and the sidewall of the second groove 411 can restrict the movement of the second protrusion 141 along a second direction.

[0054] Optionally, both the second protrusion 141 and the second groove 411 extend along a first direction. One end of the second protrusion 141 along the first direction has a third protrusion 1411, which protrudes beyond the first plane 11. That is, the second protrusion 141 extends along the first direction to protrude beyond the first plane 11, and the portion protruding beyond the first plane 11 is the third protrusion 1411. The cover plate structure has a third groove 23, and the third protrusion 1411 is located within the third groove 23. The provision of the third protrusion 1411 can further increase the volume of the electrode assembly 1 and improve the cell capacity. Furthermore, the third protrusion 1411 and the third groove 23 mutually limit each other, further ensuring that the position of the electrode assembly 1 relative to the cover plate structure does not change, thereby avoiding the risk of tensile tearing at the electrode tab 13 caused by relative displacement between the electrode assembly 1 and the cover plate structure.

[0055] Optionally, the first protruding end face 121 of the first protrusion 12 is flush with the end face of the third protrusion 1411 along the first direction. Optionally, the first protrusion 12 and the third protrusion 1411 are connected. That is, the first protrusion 12 and the third protrusion 1411 are an integral structure, which can be formed by cutting the pole assembly 1 or other processing methods. The integral structure of the two is beneficial to increasing their structural strength. The flushness of the first protruding end face 121 of the first protrusion 12 and the end face of the third protrusion 1411 along the first direction facilitates processing, and the flushness of the bottom of the connected second groove 411 and the third groove 23 also facilitates the processing of the cover plate structure.

[0056] Optionally, the third sidewall 15 of the electrode assembly 1 is perpendicular to the second direction, and one side of the second protrusion 141 perpendicular to the second direction is flush with the third sidewall 15. That is, the second protrusion 141 is disposed close to one side and flush with that side, which facilitates the processing and forming of the electrode assembly 1.

[0057] Optionally, the electrode assembly 1 has two first planes 11 at one end along the first direction. The two first planes 11 are located at the root of the first protrusion 12 on both sides along the second direction. Each of the two first planes 11 has a tab 13, which can increase the current flow of the battery cell and help dissipate heat between the tab 13 and the electrode assembly 3.

[0058] The two first sidewalls 14 of the pole group 1, which are arranged opposite each other along the third direction, each have a second protrusion 141, and each of the two second protrusions 141 has a third protrusion 1411. The third protrusion 1411 of one second protrusion 141 is located on one side of a first plane 11 along the third direction, and the third protrusion 1411 of the other second protrusion 141 is located on one side of another first plane 11 along the third direction.

[0059] Optionally, the shape of the electrode assembly 1 remains unchanged after rotating 180° along the first direction, which simplifies the positioning process during assembly and prevents assembly errors. Furthermore, the first protrusion 12 is located in the middle of this end of the electrode assembly 1, and the two third protrusions 1411 are staggered, which can further improve the overall structural strength of the protrusion structure formed by the first protrusion 12 and the two third protrusions 1411, and prevent damage to the protrusion structure and failure of the limiting function.

[0060] Optionally, the two ends of the electrode assembly 1 along the first direction are mirror-symmetrical structures, that is, the other end is also provided with a first protrusion 12, two first planes 11 and two third protrusions 1411. Optionally, in this embodiment, the two tabs 13 at one end are positive electrodes and the two tabs 13 at the other end are negative electrodes. The second protrusion 141 is provided to protrude at both ends along the first direction, and each second protrusion 141 has a third protrusion 1411 at both ends.

[0061] Optionally, such as Figure 2As shown, the cross-section of the first protrusion 12 perpendicular to the third direction is trapezoidal, with the longer side of the trapezoid closer to the first plane 11 than the shorter side. Optionally, the cross-section of the first protrusion 12 perpendicular to the third direction is an isosceles trapezoid, which can further improve the structural strength of the first protrusion 12. Correspondingly, the two opposite sides of the first groove 22 of the top cover 2 are also inclined to form an isosceles structure, so that the inclined groove side of the first groove 22 corresponds to the inclined side of the first protrusion 12, which can further improve the structural strength of the top cover 2 and improve the protective performance of the top cover 2 for the first protrusion 12.

[0062] Optionally, in this embodiment, the components of the battery cell, such as electrode group 1, are all manufactured using mature processing technologies, such as lamination, die cutting, and ultrasonic welding. Therefore, each component of the battery cell can be mass-produced and automatically formed.

[0063] Optionally, the tab 13 is located in the middle of the overall thickness direction of the electrode group 1, which is beneficial for the tabs 13 on both sides to be gathered and shaped.

[0064] Optionally, in this embodiment, the electrode post is fixed to the top cover 2 by riveting. The electrode post assembly 3 includes a riveting component, an electrode post, an upper plastic pad, a lower plastic pad, and a sealing ring. The base plate of the electrode post is located inside the cell housing, and the post body passes through the through hole on the second plane 21 and is located outside the cell housing, and is riveted to the riveting component. The sealing ring is fitted onto the electrode post, the lower plastic pad is placed between the base plate and the second plane 21, and the upper plastic pad is sandwiched between the riveting component and the second plane 21, partially covering the side of the riveting component. The base plate of the electrode post is welded to the electrode tab 13 to ensure a stable connection between the two.

[0065] Optionally, along the second direction, the width of electrode group 1 is A, satisfying: 80mm ≤ A ≤ 290mm. When the width A of electrode group 1 is less than 80mm, the width of electrode group 1 is too small, the cell is too thin and long, and the middle of electrode group 1 is prone to bending, which is not conducive to ensuring the structural strength of electrode group 1. When the width A of electrode group 1 is greater than 290mm, the width of electrode group 1 is too large, electrode group 1 is too thick, the electrolyte wetting efficiency is low, the wetting degree is poor, which is not conducive to ensuring the quality of the cell.

[0066] Optionally, the value of A can be 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 190mm, 200mm, 210mm, 220mm, 230mm, 240mm, 250mm, 260mm, 270mm, 280mm, or 290mm.

[0067] Optionally, along a third direction, the thickness of electrode group 1 is B, satisfying: 36mm ≤ B ≤ 118mm. When the thickness B of electrode group 1 is less than 36mm, electrode group 1 is too thin, and the middle part of electrode group 1 is prone to bending, which is not conducive to ensuring the structural strength of electrode group 1. When the thickness B of electrode group 1 is greater than 118mm, electrode group 1 is too thick, the electrolyte wetting efficiency is low, the wetting degree is poor, which is not conducive to ensuring the quality of the cell.

[0068] Optionally, the value of B can be 36mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm or 118mm.

[0069] Optionally, along the second direction, the width of the electrode group 1 is A, and the width of the first protruding end face 121 of the first protrusion 12 along the second direction is W, satisfying: 0.33≤W / A≤0.55. If the ratio of the width of the first protruding end face 121 of the first protrusion 12 to the overall width of the electrode group 1 is less than 0.33, then the width of the first protruding end face 121 of the first protrusion 12 is too small, the structural strength of the first protrusion 12 is too low, and when the electrode group 1 is inserted into the casing, the first protrusion 12 is easily deformed by force. In subsequent use, when the cover plate structure limits the first protrusion 12, the first protrusion 12 is also easily bent or even broken by force, which is not conducive to ensuring the quality stability of the battery cell. If the width of the first protruding end face 121 of the first protrusion 12 is greater than 0.55 of the overall width of the electrode group 1, then the width of the first protruding end face 121 of the first protrusion 12 is too large, and the size of the first plane 11 and the tab 13 on both sides is too small, which will reduce the current carrying capacity of the battery cell and fail to meet the current carrying capacity requirements of fast charging.

[0070] Optionally, the value of W / A can be 0.33, 0.35, 0.4, 0.45, 0.5 or 0.55.

[0071] Optionally, along the first direction, the height of the first protrusion 12 is H1, satisfying: 5mm ≤ H1 ≤ 15mm. The first protruding end face 121 of the first protrusion 12 is parallel to the first plane 11 and perpendicular to the first direction. The height of the first protrusion 12 is the vertical distance between the first protruding end face 121 of the first protrusion 12 and the first plane 11. When the height H1 of the first protrusion 12 is less than 5mm, the first protrusion 12 is too short, leaving insufficient space for the tab 13, which is not conducive to the shaping of the tab 13 and the connection between the tab 13 and the electrode assembly 3, and is prone to defects. When the height H1 of the first protrusion 12 is greater than 15mm, the first protrusion 12 is too high. Even with sufficient space for the tab 13, there will be some extra space at the top of the tab 13, which is not conducive to improving the volumetric energy density of the battery cell. Moreover, the excessive height of the first protrusion 12 is also not conducive to ensuring the strength of this part of the structure, and is prone to deformation and wrinkling under stress.

[0072] Optionally, the value of H1 can be 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm or 15mm.

[0073] like Figure 5 As shown, optionally, the width of the third protrusion 1411 along the third direction is K, satisfying: 8mm ≤ K ≤ 30mm. If the width K of the third protrusion 1411 is less than 8mm, the third protrusion 1411 is too narrow, its structural strength is insufficient, and it is prone to deformation under the limiting force of the cover plate structure, which is also not conducive to ensuring the processing accuracy at this point. When the overall width of the electrode group 1 remains unchanged, if the width of the third protrusion 1411 is too narrow, the width of the first plane 11 will be too large, and the excessive empty space is also not conducive to increasing the cell capacity. Furthermore, if the width of the third protrusion 1411 is too narrow, that is, the protrusion height of the second protrusion 141 along the third direction is too low, it is also not conducive to the limiting between this point and the housing 4, and the second protrusion 141 is also prone to deformation under the limiting force of the housing 4.

[0074] Optionally, the value of K can be 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm or 30mm.

[0075] like Figure 4 and Figure 5 As shown, optionally, the third protrusion 1411 is located on one side of the first plane 11 along the third direction. The side of the third protrusion 1411 that is perpendicular to the second direction and away from the first protrusion 12 is flush with the first side 111 of the first plane 11. The first side 111 is parallel to the third direction. The distance between the projection of the first protruding end face 121 of the first protrusion 12 toward the virtual extended surface of the first plane 11 and the first side 111 is L2. The length of the third protrusion 1411 along the third direction is L1, satisfying: 0.45≤L2 / L1≤0.75.

[0076] When L2 / L1 is less than 0.45, if the length of the third protrusion 1411 remains unchanged, the distance L2 between the projection of the first protruding end face 121 of the first protruding part 12 toward the virtual extended surface of the first plane 11 and the first side 111 will be too small. This results in the first plane 11 having too small a length along the second direction, and the tab 13 becoming too small, thus reducing the cell's overcurrent capacity and failing to meet the requirements of fast charging. When L2 / L1 is greater than 0.75, either the length of the third protrusion 1411 is too small, and the connection between the third protrusion 1411 and the first protrusion 12 is too narrow, making it prone to breakage under external force; or the distance L2 between the projection of the first protruding end face 121 of the first protruding part 12 toward the virtual extended surface of the first plane 11 and the first side 111 will be too large, and the first protrusion 12 having too short a length along the second direction, which is not conducive to increasing the cell's capacity. Furthermore, even with the tab 13 being long enough to meet the current requirements of fast charging, the first plane 11 still has a lot of free space, which is not conducive to improving the volumetric energy density of the battery cell.

[0077] Optionally, the value of L2 / L1 can be 0.45, 0.5, 0.55, 0.6, 0.65, 0.7 or 0.75.

[0078] Optionally, along the third direction, the width of the first protrusion 12 is E, and the thickness of the electrode assembly 1 along the third direction is B, satisfying: 0.35≤E / B≤0.55. If E / B is less than 0.35, the first protrusion 12 is too narrow, which is not conducive to ensuring the structural strength of the first protrusion 12. During the insertion of the electrode assembly 1 into the casing and the subsequent shaking of the electrode assembly 1 under force on the battery cell, the first protrusion 12 is also prone to deformation and damage. If E / B is greater than 0.55, the first protrusion 12 is too wide, and the protrusion height of the second protrusion 141 along the third direction is too low, which is not conducive to the limiting between the second protrusion 141 and the casing 4.

[0079] Optionally, the value of E / B can be 0.35, 0.4, 0.45, 0.5 or 0.55.

[0080] Optionally, the second side surface 1412 of the second protrusion 141 is perpendicular to the second direction and faces the first protrusion 12, with the second side surface 1412 opposite to the first side surface 14111. Along the second direction, the distance between the second side surfaces 1412 of the two second protrusions 141 is L3, satisfying: 4mm ≤ L3 ≤ 18mm. After the electrode assembly 1 is installed in the casing, the second side surface 1412 of the second protrusion 141 of the electrode assembly 1 corresponds to the stepped surface of the casing 4. When multiple cells are assembled into a battery module, the multiple cells are arranged sequentially along their own thickness direction, i.e., the third direction. The stepped surfaces of the casing 4 of two adjacent cells are opposite to each other. The distance L3 between the second side surfaces 1412 of the two second protrusions 141 affects whether the arrangement of the two adjacent cells is tight. If L3 is less than 4mm, the gap between the stepped surfaces of the casing 4 of two adjacent cells is too small, or even nonexistent. When the two stepped surfaces are joined, the sides of the two cells perpendicular to the second direction cannot be aligned. If the distance L3 between the second side surface 1412 of the two second protrusions 141 is greater than 18mm, the gap between the stepped surfaces of the shells 4 of the two adjacent cells will be too large, which will cause space waste and hinder the improvement of cell capacity.

[0081] Optionally, the value of L3 can be 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm or 18mm.

[0082] To verify the performance of the aforementioned battery cells, as shown in Tables 1 and 2 below, this embodiment provides six sets of example cells and six sets of comparative example cells. The similarities between the six sets of example cells and the six sets of comparative example cells are as follows: the wall thickness of the casing 4 is 0.35 mm; the material of the inner insulating film is PP; the material of the upper plastic is PPS; the material of the lower plastic is PP; along the second direction, the width A of the electrode group 1 satisfies 80 mm ≤ A ≤ 290 mm; and along the third direction, the thickness B of the electrode group 1 satisfies 36 mm. m≤B≤118mm, along the first direction, the height H1 of the first protrusion 12 satisfies: 5mm≤H1≤15mm, along the third direction, the width K of the third protrusion 1411 satisfies: 8mm≤K≤30mm, the distance L2 between the projection of the first protruding end face 121 of the first protrusion 12 toward the virtual extension surface of the first plane 11 and the first side 111, and the length L1 of the third protrusion 1411 along the third direction satisfy: 0.45≤L2 / L1≤0.75.

[0083] Table 1

[0084] category Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 W / A 0.33 0.38 0.43 0.47 0.50 0.55 K (mm) 8.00 15.00 19.00 22.00 25.00 30.00 E / B 0.35 0.39 0.44 0.48 0.50 0.55 L2 / L1 0.45 0.52 0.58 0.65 0.70 0.75 L3 (mm) 4.00 6.00 9.00 12.00 16.00 18.00 H1 (mm) 5.00 7.00 8.00 9.00 12.00 15.00 B (mm) 36.00 54.00 74.00 80.00 100.0 118.0 A (mm) 80.00 130.0 150.0 180.0 240.0 290.0

[0085] Table 2

[0086] category Comparison 1 Comparison 2 Comparison 3 Comparison 4 Comparison 5 Comparison 6 W / A 0.29 0.60 0.43 0.43 0.43 0.43 K (mm) 19.00 19.00 19.00 19.00 19.00 19.00 E / B 0.44 0.44 0.31 0.60 0.44 0.44 L2 / L1 0.58 0.58 0.58 0.58 0.58 0.58 L3 (mm) 9.00 9.00 9.00 9.00 3.00 20.00 H1 (mm) 15.00 15.00 15.00 15.00 15.00 15.00 B (mm) 74.00 74.00 74.00 74.00 74.00 74.00 A (mm) 150.0 150.0 150.0 150.0 150.0 150.0

[0087] As shown in Table 1 above, the cells of all six examples meet the following requirements: along the second direction, the width A of the electrode group 1 and the width W of the first protruding end face 121 of the first protrusion 12 along the second direction satisfy: 0.33≤W / A≤0.55; along the third direction, the width E of the first protrusion 12 and the thickness B of the electrode group 1 along the third direction satisfy: 0.35≤E / B≤0.55; and along the second direction, the distance L3 between the second side surfaces 1412 of the two second protrusions 141 satisfies: 4mm≤L3≤18mm. Testing showed that the yield rate of the cells in all six examples was greater than 98%, and no abnormalities were found, such as insufficient strength of the electrode group 1 or unstable fixation of the electrode group 1 within the cell casing. The electrode group 1, tabs 13, etc., were undamaged and undeformed, and the current carrying capacity of the cover structure met the requirements of the cell. The temperature of the tabs 13 also met the requirements of the cell.

[0088] As shown in Table 2 above, all six sets of comparative battery cells have a certain dimensional parameter that does not conform to the above-mentioned optimal value range. The yield of all six sets of comparative battery cells is less than 98%. However, compared with the existing technology that sets a protrusion at the lower plastic part to resist the electrode group 1, the volumetric energy density of all six sets of comparative battery cells is improved, and they can all prevent the electrode group 1 from moving and shifting in the housing 4 to a certain extent, thereby ensuring the stability of the battery cell quality.

[0089] The W / A ratio of the battery cell in Comparative Example 1 is 0.29, which is less than the minimum value of 0.33 in the more optimal range. This means that the length of the first protrusion 12 of the electrode group 1 along the second direction is too small in proportion to the width of the electrode group 1. Upon inspection, the structural strength of the first protrusion 12 of this battery cell is weak, and it is prone to deformation or damage.

[0090] The W / A ratio of the battery cell in Comparative Example 2 is 0.6, which is greater than the maximum value of 0.55 in the optimal range. This means that the length of the first protrusion 12 of the electrode group 1 along the second direction is too large in proportion to the width of the electrode group 1. Upon inspection, it was found that the dimensions of the first plane 11 and the tab 13 of the electrode group 1 along the second direction are both too small, which will reduce the current carrying capacity of the battery cell and fail to meet the current carrying capacity requirements of fast charging.

[0091] The E / B ratio of the battery cell in Comparative Example 3 is 0.31, which is less than the minimum value of 0.35 in the optimal range. This means that the width of the first protrusion 12 of the electrode group 1 in this battery cell is too small in proportion to the thickness of the electrode group 1. Upon inspection, the structural strength of the first protrusion 12 of the electrode group 1 in this battery cell is insufficient. During the insertion of the electrode group 1 into the casing and the subsequent shaking of the electrode group 1 under stress, the first protrusion 12 is also prone to deformation and damage.

[0092] The E / B ratio of the battery cell in Comparative Example 4 is 0.6, which is greater than the maximum value of 0.55 in the more favorable range. This means that the width of the first protrusion 12 of the electrode group 1 in this battery cell is too large in proportion to the thickness of the electrode group 1. Upon inspection, the protrusion height of the second protrusion 141 of the electrode group 1 in this battery cell is too low in the third direction, which is not conducive to the limiting of the second protrusion 141 and the housing 4. The improvement of the stability of the electrode group 1 within the battery cell housing is limited, but it is still more stable than the electrode group 1 of the battery cell in the prior art.

[0093] In Comparative Example 5, the L3 value of the battery cell is 3mm, which is less than the minimum value of 4mm in the optimal range. This means that when multiple cells from this set are assembled into a battery module, the gap between the second side faces 1412 of the electrode group 1 of two adjacent cells is too small, and the gap between the stepped surfaces of the casing 4 of two adjacent cells is even smaller. When the two stepped surfaces are joined, the sides of the two cells perpendicular to the second direction cannot be aligned. Upon inspection, it was found that when multiple cells from this set are assembled into a battery module, the sides of multiple cells perpendicular to the second direction cannot be completely aligned.

[0094] In Comparative Example 6, the L3 value of the cell is 20mm, which is greater than the maximum value of 18mm in the optimal range. This means that when multiple cells from this set are assembled into a battery module, the gap between the second side 1412 of the electrode group 1 of two adjacent cells is too large, and the gap between the stepped surfaces of the casing 4 of two adjacent cells is also too large. Testing revealed that when multiple cells from this set are assembled into a battery module, the increase in the cell capacity of the battery module is limited.

[0095] This embodiment also provides a battery module, including multiple cells as described above, at least some of which are arranged sequentially along a third direction, that is, multiple cells are arranged sequentially along their own thickness direction, the second sidewalls 41 of two adjacent cells are attached together, and the stepped surfaces at the second sidewalls 41 are arranged opposite each other.

[0096] The electrode assembly 1 of the battery module has a protruding structure at its end in a first direction, including a first protrusion 12 and two third protrusions 1411, which can greatly increase the cell capacity. Each segment of the electrode assembly 1 has two tabs 13. Since the protruding structure is located on one side of the tab 13 along a third direction, the tabs 13 no longer need to be aligned in a straight line with the pressing position, thus increasing the length of the tabs 13 and improving the cell's current carrying capacity to meet the higher current requirements of fast charging. Furthermore, the dispersed arrangement of the tabs 13 facilitates heat dissipation at the tabs 13, improving the cell's safety. The protruding structure of the electrode assembly 1 cooperates with the groove structure of the top cover 2. Compared to the prior art where the electrode assembly 1 is simply pressed from the first direction, the electrode assembly 1 in this embodiment has more comprehensive positioning, lower risk of displacement or shifting, and thus improves the cell's process yield and performance. Furthermore, through optimized dimensional design, a gap is reserved between the second side surfaces 1412 of the second protrusions 141 on both sides of the electrode assembly 1, which solves the problem of misalignment after the cells are assembled. Additionally, the tabs 13 are located in the middle of the overall thickness direction of the electrode assembly 1, which facilitates the convergence of the tabs 13 on both sides, further reducing manufacturing difficulty and ensuring the quality of the tabs 13. Moreover, the electrode assembly 1 is structurally symmetrical along the first direction, and each end is designed to overlap after a 180° rotation, which further reduces the processing and assembly process window and improves process efficiency. Furthermore, by standardizing the design parameters of the electrode assembly 1, the process yield can be further improved. This battery module has a higher volumetric energy density and helps prevent the electrode assembly 1 from shifting within the casing 4, resulting in higher quality stability.

[0097] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A battery cell, characterized in that, include: The pole group (1) has a first plane (11) and a first protrusion (12) at one end along a first direction. The first protrusion (12) protrudes along the first direction. The first plane (11) is located at the root of the first protrusion (12) on one side along a second direction. The first plane (11) has a tab (13). The first direction is perpendicular to the second direction. The cover plate structure includes a top cover (2) and a pole post assembly (3). The top cover (2) has a second plane (21) and a first groove (22). The second plane (21) is located at the edge of the groove opening of the first groove (22). The second plane (21) is set corresponding to the first plane (11). The pole post assembly (3) is set at the second plane (21). The pole post assembly (3) is connected to the pole lug (13). The first protrusion (12) is located in the first groove (22). The battery cell also includes a housing (4), and the cover plate structure is provided over the opening of the housing (4) to form the battery cell outer shell, and the electrode group (1) is disposed inside the battery cell outer shell; The first sidewall (14) of the pole group (1) has a second protrusion (141), and the first sidewall (14) is perpendicular to a third direction, which is perpendicular to both the first direction and the second direction; The second sidewall (41) of the housing (4) has a second groove (411), the second sidewall (41) is provided corresponding to the first sidewall (14), and the second protrusion (141) is located in the second groove (411); The second protrusion (141) and the second groove (411) both extend along the first direction. The second protrusion (141) has a third protrusion (1411) at one end along the first direction. The third protrusion (1411) protrudes from the first plane (11). The cover plate structure has a third groove (23). The third protrusion (1411) is located in the third groove (23). The first protruding end face (121) of the first protrusion (12) is flush with the end face of the third protrusion (1411) along the first direction; And / or, the first protrusion (12) is connected to the third protrusion (1411); And / or, the third sidewall (15) of the pole group (1) is perpendicular to the second direction, and one side of the second protrusion (141) perpendicular to the second direction is flush with the third sidewall (15).

2. The battery cell according to claim 1, characterized in that, Along the second direction, the width of the pole group (1) is A, which satisfies: 80mm≤A≤290mm; And / or, along a third direction, the thickness of the pole group (1) is B, satisfying: 36mm≤B≤118mm, and the third direction is perpendicular to both the first direction and the second direction; And / or, along the second direction, the width of the pole group (1) is A, and the width of the first protruding end face (121) of the first protrusion (12) along the second direction is W, satisfying: 0.33≤W / A≤0.55; And / or, along the first direction, the height of the first protrusion (12) is H1, satisfying: 5mm≤H1≤15mm.

3. The battery cell according to claim 1, characterized in that, Along the third direction, the width of the third protrusion (1411) is K, which satisfies: 8mm≤K≤30mm; And / or, the third protrusion (1411) is at least partially located on one side of the first plane (11) along the third direction, the first side surface (14111) of the third protrusion (14111) is perpendicular to the second direction and is disposed away from the first protrusion (12), the first side surface (14111) is flush with the first side edge (111) of the first plane (11), the first side edge (111) is parallel to the third direction, the distance between the projection of the first protruding end face (121) of the first protrusion (12) toward the virtual extension surface of the first plane (11) and the first side edge (111) is L2, and the length of the third protrusion (1411) along the third direction is L1, satisfying: 0.45≤L2 / L1≤0.

75.

4. The battery cell according to claim 3, characterized in that, The pole group (1) has two first planes (11) at one end along the first direction. The two first planes (11) are located at the root of the first protrusion (12) on both sides along the second direction. Each of the two first planes (11) has a tab (13). The pole group (1) has two first sidewalls (14) arranged opposite each other along the third direction, each having a second protrusion (141) and a third protrusion (1411). The third protrusion (1411) of one second protrusion (141) is located on one side of one first plane (11) along the third direction, and the third protrusion (1411) of the other second protrusion (141) is located on one side of the other first plane (11) along the third direction.

5. The battery cell according to claim 4, characterized in that, Along the third direction, the width of the first protrusion (12) is E, and the thickness of the pole group (1) is B, satisfying: 0.35≤E / B≤0.55; And / or, the second side (1412) of the second protrusion (141) is perpendicular to the second direction and faces the first protrusion (12), and along the second direction, the distance between the second side (1412) of the two second protrusions (141) is L3, satisfying: 4mm≤L3≤18mm.

6. The battery cell according to any one of claims 1-3, characterized in that, The first protrusion (12) has a trapezoidal cross section perpendicular to the third direction. The long side of the trapezoid is closer to the first plane (11) than the short side of the trapezoid. The third direction is perpendicular to both the first direction and the second direction.

7. A battery module, characterized in that, It includes a plurality of battery cells as described in any one of claims 1-6, at least some of the battery cells being arranged sequentially along a third direction, the third direction being perpendicular to both the first direction and the second direction.

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