Battery cells, batteries, and power consumption devices

Abstract

This application provides a battery cell, a battery, and a power-consuming device. The battery cell includes a case, an end cap, and an electrode assembly. At least one end of the case along a first direction has an opening, the case includes a first wall, the end cap seals the opening, and the first wall is welded to the end cap to form a first connection. The electrode assembly is at least partially housed within the case and includes a positive electrode plate and a negative electrode plate, at least a portion of the positive electrode plate and at least a portion of the negative electrode plate are stacked along a second direction, the second direction being parallel to the thickness direction of the first wall, and the first direction intersecting the second direction. The first wall includes a first region and a second region arranged along the first direction, the thickness of the first region being greater than the thickness of the second region, and the first region being located between the first connection and the second region. The region of the first wall located near the first connection is reduced to reduce the risk of fatigue and cracking due to expansion of the electrode assembly, and further improves the service life of the battery cell.

Description

[Technical Field]

[0001] (Cross-reference of related applications) This application claims priority to international patent application PCT / CN2024 / 089160, filed on 22 April 2024, titled "Battery Cells, Batteries and Power Consumption Devices"; international patent application PCT / CN2023 / 135607, filed on 30 November 2023, titled "Battery Cells, Batteries, Power Consumption Equipment and Energy Storage Devices"; and international patent application PCT / CN2023 / 134129, filed on 24 November 2023, titled "Cases, Battery Cells, Batteries and Power Consumption Devices," the contents of all three applications being incorporated herein by reference.

[0002] This application relates to the battery technology field, and more specifically to battery cells, batteries, and power consumption devices. [Background technology]

[0003] Energy conservation and reduction of pollutant emissions are key to the sustainable development of the automotive industry, and electric vehicles, with their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. However, battery technology is a crucial element in the development of electric vehicles.

[0004] In battery technology, the lifespan of battery cells is a critical issue that cannot be ignored. Therefore, improving the lifespan of battery cells is one of the urgent technical problems that needs to be solved in battery technology. [Overview of the Initiative]

[0005] The embodiments of this application provide a battery cell, a battery, and a power-consuming device that can effectively improve the service life of the battery cell.

[0006] According to a first aspect, an embodiment of the present application provides a battery cell comprising a case, an end cap, and an electrode assembly, wherein at least one end of the case along a first direction has an opening, the case comprises a first wall, the end cap seals the opening, the first wall is welded to the end cap to form a first connection, the electrode assembly is at least partially housed within the case, the electrode assembly comprises a positive electrode plate and a negative electrode plate, at least a portion of the positive electrode plate and at least a portion of the negative electrode plate are stacked along a second direction, the second direction is parallel to the thickness direction of the first wall, the first direction intersects the second direction, the first wall comprises a first region and a second region arranged along the first direction, the thickness of the first region is greater than the thickness of the second region, and the first region is located between a first connection and a second region.

[0007] In the above proposed technology, the thickness of the first region is greater than the thickness of the second region, and the first region is located between the first connection and the second region. As a result, the thicker first region is closer to the first connection than the second region, and the first region provides a reinforcing effect on the region of the first wall located near the first connection, reducing the risk of fatigue and cracking of the region of the first wall located near the first connection due to expansion of the electrode assembly, and further improving the service life of the battery cell.

[0008] In some embodiments, the electrode assembly has a flat region, and the portions of the positive electrode plate located in the flat region and the portions of the negative electrode plate located in the flat region are stacked along a second direction. The second direction is the stacking direction of the portions of the positive electrode plate located in the flat region and the portions of the negative electrode plate located in the flat region, and the amount of expansion of the electrode assembly along the second direction during the cycling process is greater, and the first wall is more affected by the expansion of the electrode assembly. However, the first region acts as a reinforcement to the region of the first wall located near the first connection, thereby reducing the risk of the first wall fatigue and cracking near the first connection due to the expansion of the electrode assembly.

[0009] In some embodiments, the electrode assembly includes an adjacent first surface and a second surface, the first surface being perpendicular to the second direction, the area of ​​the first surface being larger than the area of ​​the second surface, and the first surface and the first wall being positioned opposite each other along the second direction. The area of ​​the first surface being larger than the area of ​​the second surface is thereby greater than the expansion force experienced by the first wall positioned opposite the first surface in the case. The first region acts as a reinforcement to the region of the first wall located near the first connection, thereby reducing the risk of the first wall fatigue and cracking near the first connection due to the expansion of the electrode assembly.

[0010] In some embodiments, the first surface is the largest surface area of ​​the outer surface of the electrode assembly. It maximizes the expansion force experienced by the first wall, which is positioned opposite the first surface in the case. The first region acts as a reinforcement to the region of the first wall located near the first connection, thereby reducing the risk of the first wall fatigue and cracking near the first connection due to the expansion of the electrode assembly.

[0011] In some embodiments, the electrode assembly is a wound structure, and the electrode assembly further has a corner region, the corner region is located at at least one end of the flat region along a third direction, the first direction, the second direction and the third direction are not coplanar and intersect in pairs, the outer surface of the flat region includes a first surface, the outer surface of the corner region includes a second surface, and at least a portion of the second surface is an arcuate surface. In the case of a wound electrode assembly, the amount of expansion of the flat region in the second direction is greater. The first region provides a reinforcing effect to the region located near the first connection of the first wall, thereby effectively reducing the risk of the first wall fatigue and cracking near the first connection due to the expansion of the electrode assembly.

[0012] In some embodiments, the electrode assembly is a laminated structure, where a flat region includes a plurality of positive electrode plates and a plurality of negative electrode plates, which are stacked and installed along a second direction, and the first surface is perpendicular to the second surface. In the case of a laminated electrode assembly, the amount of expansion of the positive electrode plates and negative electrode plates of the electrode assembly in the stacking direction is greater. The first region acts as a reinforcement to the region located near the first connection of the first wall, thereby effectively reducing the risk of the first wall fatigue and cracking near the first connection due to the expansion of the electrode assembly.

[0013] In some embodiments, the first wall is the wall with the largest outer surface area in the case. The wall with the largest outer surface area in the case is more easily deformed after being subjected to the expansion force of the electrode assembly, and because the first wall is the wall with the largest outer surface area in the case, the risk of the wall with the largest outer surface area in the case fatigue and cracking near the first connection due to the expansion of the electrode assembly is reduced.

[0014] In some embodiments, the case includes two first walls, which are positioned opposite each other along a second direction, and the electrode assembly is located between the two first walls. In this way, the risk of the two first walls fatigue and cracking near the first connection due to the expansion of the electrode assembly is reduced.

[0015] In some embodiments, the first region includes a first portion and a second portion arranged along a first direction, the second portion connecting the first portion and the second region, and the thickness of the first portion is greater than the thickness of the second portion. The region adjacent to the first connection in the first region is more prone to forming a heat-affected zone, and this region is more susceptible to fatigue and cracking. However, because the second portion connects the first portion and the second region, and the thickness of the first portion is greater than the thickness of the second portion, the thicker first portion in the first region is brought closer to the first connection, effectively reducing the influence of the heat-affected zone on the first region and lowering the risk of fatigue and cracking in the region of the first wall located near the first connection. Furthermore, because the thickness of the second portion is less than the thickness of the first portion, the amount of material used in the first region can be reduced, thereby lowering production costs.

[0016] In some embodiments, the thickness of the second portion tends to decrease along the direction in which the end cap faces the electrode assembly. On the one hand, this reduces the influence of the second portion on the electrode assembly and lowers the risk of interference between the second portion and the electrode assembly. On the other hand, it tends to increase the reinforcing effect of the second portion along the direction in which the electrode assembly faces the end cap, so that the region of the second portion adjacent to the first portion is still well reinforced even when affected by the first connection, reducing the risk of the first wall fatigue and cracking at the second portion. Furthermore, the second portion enables a transition between the first portion and the second region, reducing stress concentration.

[0017] In some embodiments, the size of the first region along the third direction is larger than the size of the first region along the first direction, and the first, second, and third directions are not coplanar but intersect in pairs. Increasing the size of the first region along the third direction reinforces the strength of more areas along the third direction of the first wall, further reducing the risk of fatigue and cracking of areas located near the first connection point of the first wall.

[0018] In some embodiments, the first region includes a first connecting segment, the first connecting segment passing through the middle section of the first wall, the middle section being perpendicular to the third direction, and the distance from the middle section to both ends of the first wall along the third direction being equal. When the first wall is subjected to the expansion force of the electrode assembly of the battery cell, the deformation of the intermediate region of the first wall along the third direction becomes greater, and the intermediate region of the first wall along the third direction becomes more fatigued and prone to cracking. Because the first connecting segment of the first region passes through the middle section of the first wall, the strength of at least the intermediate region of the first wall along the third direction is reinforced, reducing the risk of the intermediate region of the first wall along the third direction fatigued and cracking near the first connection.

[0019] In some embodiments, the first region further includes a second and a third connecting segment, the second, first, and third connecting segments arranged along the third direction, the first connecting segment connecting the second and third connecting segments, and the thickness of the first connecting segment is greater than the thickness of the second and third connecting segments. When the first wall is subjected to the expansion force of the electrode assembly, the amount of deformation of the first wall gradually decreases along the third direction from the middle to both ends. By dividing the first region into a multi-stage structure and setting the thickness of the first connecting segment located in the intermediate region to be greater than that of the first connecting segment, and setting the thickness of the second and third connecting segments located at both ends of the first connecting segment to be smaller, the first region is intentionally designed based on the difference in the amount of deformation of different regions of the first wall along the third direction, thereby intentionally improving the strength of different regions of the first wall along the third direction, providing sufficient strength to the region located near the first connection of the first wall, while simultaneously reducing the amount of material used in the first region and lowering production costs.

[0020] In some embodiments, the first region further includes a first transition segment, the first connecting segment, the first transition segment and the second connecting segment are arranged along a third direction, the first transition segment connects the second connecting segment and the first connecting segment, and the thickness of the first transition segment tends to increase along the direction in which the second connecting segment moves toward the first connecting segment, and / or, the first region further includes a second transition segment, the first connecting segment, the second transition segment and the third connecting segment are arranged along a third direction, the second transition segment connects the third connecting segment and the first connecting segment, and the thickness of the second transition segment tends to increase along the direction in which the third connecting segment moves toward the first connecting segment. When the second connecting segment and the first connecting segment are connected via the first transition segment, and the thickness of the first transition segment tends to increase along the direction in which the second connecting segment moves toward the first connecting segment, the first transition segment can realize a transition between the second connecting segment and the first connecting segment and reduce stress concentration. If a third connecting segment and a first connecting segment are connected via a second transition segment, and the thickness of the second transition segment tends to increase in the direction in which the third connecting segment moves toward the first connecting segment, then the second transition segment can facilitate a transition between the third connecting segment and the first connecting segment, thereby reducing stress.

[0021] In some embodiments, the size of the first connecting segment along the third direction is L1, the size of the first wall along the third direction is L, and 0.2 ≤ L1 / L ≤ 0.6. If L1 / L ≥ 0.2, the ratio of the size of the first connecting segment along the third direction in the first wall is increased, thereby increasing the area in which the intermediate region of the first wall along the third direction is reinforced, and improving the strength of the intermediate region of the first wall along the third direction. If L1 / L ≤ 0.6, the ratio of the size of the first connecting segment along the third direction in the first wall is decreased, reducing the amount of material used for the first connecting segment and lowering production costs. Therefore, by setting the ratio of the size of the first connecting segment along the third direction to the size of the first wall along the third direction to 0.2 to 0.6, the first connecting segment is given sufficient reinforcement capacity while reducing the amount of material used for the first connecting segment, thus achieving both the reinforcement capacity requirement and the economic requirement for the first connecting segment.

[0022] In some embodiments, the first connecting segment has first and second ends facing each other along a third direction, the first wall has third and fourth ends facing each other along a third direction, the first end is close to the third end, the second end is close to the fourth end, the size of the first wall along the third direction is L, the minimum distance along the third direction between the first end and the third end is L2, the minimum distance along the third direction between the second end and the fourth end is L3, L2 / L ≤ 0.3, and / or L3 / L ≤ 0.3. When L2 / L ≤ 0.3, the ratio of the minimum distance along the third direction between the first end and the third end to the size of the first wall along the third direction is reduced, thereby reinforcing the strength of more areas of the first wall along the third direction and further reducing the risk of fatigue and cracking of areas of the first wall located near the first connection. If L3 / L ≤ 0.3, the ratio of the minimum distance along the third direction between the second and fourth ends to the size of the first wall along the third direction is reduced, thereby reinforcing the strength of more areas of the first wall along the third direction and further reducing the risk of fatigue and cracking in areas of the first wall located near the first connection point.

[0023] In some embodiments, 100mm ≤ L ≤ 450mm.

[0024] In some embodiments, the case includes a corner wall, with corner walls connected to both ends of the first wall along a third direction, and at least one end of the first region along a third direction not in contact with a corner wall, or both ends of the first region along a third direction extend to two corner walls each. If at least one end of the first region along a third direction does not in contact with a corner wall, the amount of material used in the first region can be reduced, lowering production costs. If both ends of the first region along a third direction extend to two corner walls each, the length of the first region can be increased, improving the reinforcing capacity of the first region, reinforcing a larger area of ​​the first wall along a third direction, and further reducing the risk of fatigue and cracking in the area located near the first connection point of the first wall.

[0025] In some embodiments, the electrode assembly further includes a separator member, which is placed between a positive electrode plate and a negative electrode plate, the positive electrode plate includes a positive electrode body region and a positive electrode tab protruding from the positive electrode body region, the positive electrode body region having a positive electrode active material layer, the negative electrode plate includes a negative electrode body region and a negative electrode tab protruding from the negative electrode body region, the negative electrode body region having a negative electrode active material layer, along a first direction, the positive electrode body region having a fifth end facing an end cap, the negative electrode body region having a sixth end facing an end cap, the separator member having a seventh end facing an end cap, the seventh end being closer to the end cap than the fifth and sixth ends. The separator member has portions that protrude from the fifth and sixth ends to enhance the insulating effect of the separator member between the positive electrode plate and the negative electrode plate and to reduce the risk of the positive electrode plate and the negative electrode plate coming into contact.

[0026] In some embodiments, the separator member includes overhanging regions extending from the fifth and sixth ends along the first direction, such that the orthographic projection of the overhanging regions partially overlaps with the orthographic projection of the first region in a projection plane perpendicular to the second direction. Such a structure can increase the size of the first region along the first direction, improving the reinforcing capacity of the first region, reinforcing a larger area of ​​the first wall along the first direction, and further reducing the risk of fatigue and cracking in areas located near the first connection of the first wall.

[0027] In some embodiments, the second region has a first inner surface facing the internal space of the case, the first region includes a first projection protruding from the first inner surface, and in a projection plane perpendicular to the second direction, the orthographic projection of the positive electrode body region does not overlap with the orthographic projection of the first projection, and / or, in a projection plane perpendicular to the second direction, the orthographic projection of the negative electrode body region does not overlap with the orthographic projection of the first projection. If the orthographic projection of the positive electrode body region and the orthographic projection of the first projection do not overlap in a projection plane perpendicular to the second direction, the case can provide greater expansion space for the electrode assembly, reducing the risk of the electrode assembly expanding and directly applying expansion force to the first projection, reducing the amount of deformation of the first wall, and further reducing the risk of fatigue and cracking of the region of the first wall located near the first connection. If the orthographic projection of the negative electrode body region and the orthographic projection of the first protrusion do not overlap in a projection plane perpendicular to the second direction, the case can provide greater expansion space for the electrode assembly, reducing the risk of the electrode assembly expanding and directly applying expansion force to the first protrusion, reducing the amount of deformation of the first wall, and further reducing the risk of fatigue and cracking of the region of the first wall located near the first connection.

[0028] In some embodiments, the negative electrode plate includes a negative electrode current collector and a negative electrode active material layer installed on at least one side of the negative electrode current collector, the negative electrode active material layer includes a negative electrode active material.

[0029] In some embodiments, the negative electrode active material layer includes a negative electrode body and a negative electrode thin-walled portion, which are arranged along a first direction, with the negative electrode thin-walled portion positioned along the first direction at one end of the negative electrode body adjacent to the end cap. The electrode assembly has a larger expansion gap in the region corresponding to the negative electrode thin-walled portion, which applies less force to the first wall after expansion, and can reduce the risk of fatigue and cracking in the region located near the first connection of the first wall.

[0030] In some embodiments, the orthographic projection of the negative electrode thin-wall and the orthographic projection of the first region are spaced apart along the first direction in a projection plane perpendicular to the second direction. This reduces the influence of the negative electrode thin-wall on the first region, reduces the risk of the electrode assembly expanding and directly applying expansion forces to the first region, and further reduces the risk of fatigue and cracking of the region located near the first connection of the first wall.

[0031] In some embodiments, the spacing between the orthographic projection of the negative electrode thin-walled portion and the orthographic projection of the first region along the first direction in a projection plane perpendicular to the second direction is 1 mm or more. This increases the distance between the orthographic projection of the negative electrode thin-walled portion and the orthographic projection of the first region along the first direction in a projection plane perpendicular to the second direction, further reducing the influence of the negative electrode thin-walled portion on the first region.

[0032] In some embodiments, the coating weight of the negative electrode active material layer on one side was 90 mg / 1540 mm². 2 ~170mg / 1540mg 2 The coating weight on one side of the negative electrode active material layer is related to the expansion of the negative electrode active material layer, and the coating weight on one side of the negative electrode active material layer is 90 mg / 1540 mm. 2 ~170mg / 1540mg 2 By setting it to this configuration, it is possible to achieve a certain degree of compatibility between the high energy density requirement of the battery cell and the low expansion requirement of the negative electrode plate. This reduces the impact of the negative electrode plate expansion on the first wall and reduces the risk of fatigue and cracking in the region of the first wall located near the first connection point.

[0033] In some embodiments, the coating weight of the negative electrode active material layer on one side was 110 mg / 1540 mm². 2 ~150mg / 1540mg 2 This allows for further improvement of the energy density of the battery cell and further reduction of the expansion of the negative electrode plate.

[0034] In some embodiments, the porosity of the negative electrode plate is 27% to 40%. In this way, the negative electrode plate provides space for impurities generated by side reactions, mitigates the expansion of the negative electrode plate, and reduces the impact of the negative electrode plate expansion on the first wall.

[0035] In some embodiments, the negative electrode active material includes a silicon-based material, and the mass content of silicon elements in the silicon-based material in the negative electrode active material is 0.3% to 10%, and selectively 1% to 6%.

[0036] In some embodiments, the silicon-based material includes at least one of a silicon-oxygen compound and a silicon-carbon composite.

[0037] In some embodiments, the positive electrode plate includes a positive electrode current collector and a positive electrode active material layer installed on at least one side of the positive electrode current collector, the positive electrode active material layer includes a positive electrode active material.

[0038] In some embodiments, the positive electrode active material layer includes a positive electrode body and a positive electrode thin-walled portion, which are arranged along a first direction, with the positive electrode thin-walled portion positioned along the first direction at one end of the positive electrode body adjacent to the end cap. The electrode assembly has a larger expansion gap in the region corresponding to the positive electrode thin-walled portion, and the region of the electrode assembly corresponding to the positive electrode thin-walled portion exerts less force on the first wall after expansion, reducing the risk of fatigue and cracking in the region located near the first connection of the first wall.

[0039] In some embodiments, in a projection plane perpendicular to the second direction, the orthographic projection of the positive electrode thin portion and the orthographic projection of the first region are arranged at intervals along the first direction. It is possible to reduce the influence of the positive electrode thin portion on the first region, reduce the risk that the electrode assembly expands and directly applies an expansion force to the first region, and further reduce the risk that the region located near the first connection portion of the first wall is fatigued and cracked.

[0040] In some embodiments, in a projection plane perpendicular to the second direction, the interval size along the first direction between the orthographic projection of the positive electrode thin portion and the orthographic projection of the first region is 1 mm or more. Thereby, in the projection plane perpendicular to the second direction, the distance along the first direction between the orthographic projection of the positive electrode thin portion and the orthographic projection of the first region becomes farther, and the influence of the positive electrode thin portion on the first region is further reduced.

[0041] In some embodiments, the one-sided coating weight of the positive electrode active material layer is 200 mg / 1540 mm 2 ~370 mg / 1540 mm 2 is. The one-sided coating weight of the positive electrode active material layer is related to the expansion of the positive electrode active material layer. By setting the one-sided coating weight of the positive electrode active material layer to 200 mg / 1540 mm 2 ~370 mg / 1540 mm 2 it is possible to balance the high energy density requirement of the battery cell and the low expansion requirement of the positive electrode plate to a certain extent, thereby reducing the influence of the expansion of the positive electrode plate on the first wall and reducing the risk that the region located near the first connection portion of the first wall is fatigued and cracked.

[0042] In some embodiments, the one-sided coating weight of the positive electrode active material layer is 240 mg / 1540 mm 2 ~330 mg / 1540 mm 2 is. It is possible to further improve the energy density of the battery cell and further relieve the expansion of the positive electrode plate.

[0043] In some embodiments, the positive electrode active material is a lithium-containing phosphate.

[0044] In some embodiments, the case material includes steel, the maximum thickness of the second region is D1, the size of the case along the second direction is D, and 0.001 ≤ D1 / D ≤ 0.012. For a steel case, if D1 / D ≥ 0.001, the proportion of the case thickness in the second region is increased, providing sufficient strength to the second region and meeting the strength requirements of the case. If D1 / D ≤ 0.012, the proportion of the case thickness in the second region is decreased, and if the case volume is constant, the internal space of the case is increased, further leaving more space for the electrode assembly and meeting the requirements for the volumetric energy density of the battery cell.

[0045] In some embodiments, the case material includes steel, the maximum thickness of the second region is D1, where 0.08 mm ≤ D1 ≤ 0.35 mm, and / or the maximum thickness of the first region is D2, where 0.1 mm ≤ D2 ≤ 0.6 mm. In the case of a steel case, setting the maximum thickness of the second region to 0.08 mm to 0.35 mm not only satisfies the strength requirements of the second region but also satisfies the requirements for the volumetric energy density of the battery cell. Setting the maximum thickness of the first region to 0.1 mm to 0.6 mm provides sufficient strength to the first region and reinforces the strength of the region located near the first connection point of the first wall.

[0046] In some embodiments, the case material includes an aluminum alloy, the maximum thickness of the second region is D1, the size of the case along the second direction is D, and 0.005 ≤ D1 / D ≤ 0.065. For cases made of aluminum alloy, if D1 / D ≥ 0.005, the proportion of the case thickness in the second region is increased, providing sufficient strength to the second region and meeting the strength requirements of the case. If D1 / D ≤ 0.065, the proportion of the case thickness in the second region is decreased, and if the case volume is constant, the internal space of the case is increased, further leaving more space for the electrode assembly and meeting the requirements for the volumetric energy density of the battery cell.

[0047] In some embodiments, the case material includes an aluminum alloy, the maximum thickness of the second region is D1, where 0.4 mm ≤ D1 ≤ 0.8 mm, and / or the maximum thickness of the first region is D2, where 0.5 mm ≤ D2 ≤ 1.5 mm. In the case of a case made of aluminum alloy, setting the maximum thickness of the second region to 0.4 mm to 0.8 mm not only satisfies the strength requirements of the second region but also satisfies the requirements for the volumetric energy density of the battery cell. Setting the maximum thickness of the first region to 0.5 mm to 1.5 mm provides sufficient strength to the first region and reinforces the strength of the region located near the first connection point of the first wall.

[0048] In some embodiments, the aluminum alloy contains, by mass percentage, aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%. Such aluminum alloys have good workability and facilitate the forming of cases.

[0049] In some embodiments, the first region is directly connected to the first connection. Bringing the first region and the first connection closer together along the first direction and positioning the first region near the first connection further reduces the risk of the region of the first wall located near the first connection becoming fatigued and cracking due to expansion of the electrode assembly.

[0050] In some embodiments, the first wall further includes a first transition region, the first transition region being connected to one end of the first region away from the second region along a first direction, the first transition region being connected to a first connection, the connection position between the first transition region and the first connection, forming a first connection interface, the first connection interface having a first position closest to the first region along a first direction, and the first position located at one end of the first region away from the second region along a first direction. The first transition region is connected to the first connection to form a first connection interface, thereby the first transition region and the first connection have a sufficiently large contact area, improving the post-weld robustness between the first wall and the end cap.

[0051] In some embodiments, at least a portion of the first connection interface extends at an angle with respect to a second direction. After the end cap and the first wall are welded, the first connection shrinks as it solidifies, generating tensile stress on the first transition region. When the first wall is subjected to the expansion force of the electrode assembly, the first wall deforms, generating tensile stress on the first transition region with respect to the first connection. Because at least a portion of the first connection interface extends at an angle with respect to a second direction, the tensile stress generated on the first transition region by the contraction of the first connection and the tensile stress generated on the first connection region by the deformation of the first wall are not collinear near the portion of the first connection interface that extends at an angle with respect to a second direction, thereby reducing the risk of fatigue and cracking in the region of the first transition region located near the first connection interface.

[0052] In some embodiments, the first connection interface includes a first interface which extends inclined toward the end cap from a first position, and along a second direction, at least a portion of the first transition region is located between the first interface and the end cap. The first connection provides protection to the first transition region, and when the first wall is subjected to the expansion force of the electrode assembly, the deformation of the first transition region during the process of being subjected to the force is prevented by the first connection, reducing the risk of fatigue and cracking of the region of the first transition region located near the first interface.

[0053] In some embodiments, the first interface is connected to the outer surface of the first region at a first position. This directly connects the first region and the first connection, bringing them closer together along the first direction and further reducing the risk of fatigue and cracking of the region of the first wall located near the first connection due to expansion of the electrode assembly.

[0054] In some embodiments, the first connecting interface includes a second interface, the second interface extending inclined away from the first position and away from the end cap, and along the second direction, at least a portion of the first transition region is located on one side of the second interface away from the end cap. This allows the first transition region to act as a limiting force on the first connection, reducing the risk of the first connection coming loose.

[0055] In some embodiments, the second interface is connected to the inner surface of the first region at a first position. This directly connects the first region and the first connection, bringing them closer together along the first direction and further reducing the risk of fatigue and cracking of the region of the first wall located near the first connection due to expansion of the electrode assembly.

[0056] In some embodiments, the Vickers hardness of the first transition region is lower than that of the second region, and / or the Vickers hardness of the first transition region is lower than that of the first connection. When the Vickers hardness of the first transition region is lower than that of the second region, the first transition region with the lower Vickers hardness can be connected to the first connection, easing the stiff tension between the first wall and the first connection when the first wall deforms, and reducing the risk of separation between the first wall and the first connection. When the Vickers hardness of the first transition region is lower than that of the first connection, the first transition region becomes more deformable than the first connection, easing the stiff tension between the first wall and the first connection when the first wall deforms, and reducing the risk of separation between the first wall and the first connection.

[0057] In some embodiments, along the first direction, the first connection interface is closer to the second region than to the outer surface of the end cap. This allows the first connection to sink deeper into the first wall, effectively improving the connection strength between the first wall and the end cap.

[0058] In some embodiments, the case further includes a second wall and a corner wall, where the first wall, corner wall, and second wall are arranged along the circumferential direction of the opening, and the corner wall connects the first wall and the second wall. In this way, the first wall can transition to the second wall via the corner wall, effectively reducing the risk of stress concentration occurring at the corner locations of the case.

[0059] In some embodiments, the corner wall is welded to the end cap to form a second joint, and the corner wall includes a third and a fourth region aligned along a first direction, the thickness of the third region being greater than that of the fourth region, and the third region being located between the fourth region and the second joint. The thickness of the third region is greater than that of the fourth region, and the third region is located between the second joint and the fourth region, so that the thicker third region is closer to the second joint than the fourth region, and the third region provides a reinforcing effect on the region of the corner wall located near the second joint, reducing the risk of fatigue and cracking of the region of the corner wall located near the second joint, and further improving the service life of the battery cell.

[0060] In some embodiments, the third region is directly connected to the first region. By directly connecting the third region and the first region, the first and third regions are integrated, and the third and first regions have a mutually reinforcing effect, improving the reinforcing effect on the first wall of the first region and the reinforcing effect on the corner wall of the second region.

[0061] In some embodiments, along the circumferential direction of the opening, the corner wall has a first connecting end and a second connecting end, the first wall being connected to the first connecting end and the second wall being connected to the second connecting end, and the thickness of the third region tends to decrease along the direction from the first connecting end toward the second connecting end. When the first wall is subjected to the expansion force of the electrode assembly in the second direction, the first wall may deform and deform the corner wall, and the closer the corner wall is to the first wall along the circumferential direction of the opening, the greater the influence of the first wall on the corner wall, and the greater the deformation of the region of the corner wall that is close to the first wall. The thickness of the third region tends to decrease along the direction from the first connecting end toward the second connecting end, which increases the strength of the region of the third region that is close to the first wall along the circumferential direction of the opening, further reduces the influence of deformation of the first wall on the corner wall, provides sufficient strength to the neighboring region located at the second connection of the corner wall, and at the same time reduces the amount of material used in the third region, thereby reducing production costs.

[0062] In some embodiments, the third region is directly connected to the second connection. Bringing the third region and the second connection closer together along the first direction and positioning the third region near the second connection further reduces the risk of fatigue and cracking of the region of the corner wall located near the second connection.

[0063] In some embodiments, the corner wall further includes a second transition region, the second transition region being connected to one end of the third region away from the fourth region along a first direction, the second transition region being connected to a second connection, the connection position between the second transition region and the second connection, forming a second connection interface, the second connection interface having a second position closest to the third region along a first direction, and the second position located at one end of the third region away from the fourth region along a first direction. The second transition region is connected to the second connection to form a second connection interface, thereby the second transition region and the second connection have a sufficiently large contact area, improving the post-weld robustness between the corner wall and the end cap.

[0064] In some embodiments, at least a portion of the second connection interface extends inclined with respect to the thickness direction of the corner wall. Near the portion of the second connection interface that extends inclined with respect to the thickness direction of the corner wall, the tensile stress generated in the second transition region by contraction of the second connection and the tensile stress generated in the second transition region by deformation of the corner wall are not collinear, reducing the risk of fatigue and cracking in the region of the second transition region located near the second connection interface.

[0065] In some embodiments, the second connecting interface includes a third interface, which extends inclined toward the end cap from the second position, and along the thickness direction of the corner wall, at least a portion of the second transition region is located between the third interface and the end cap. The second connecting portion provides protection to the second transition region, preventing it from deforming outward and reducing the risk of fatigue and cracking of the region of the second transition region located near the third interface.

[0066] In some embodiments, the third interface connects the outer surface of the third region to the second location. This directly connects the third region and the second connection, bringing them closer together along the first direction and further reducing the risk of fatigue and cracking in the region located near the second connection of the corner wall.

[0067] In some embodiments, the second connection interface includes a fourth interface, which extends inclined away from the end cap from the second position, and along the thickness direction of the corner wall, at least a portion of the second transition region is located on one side of the fourth interface away from the end cap. This allows the second transition region to act as a limiting force on the second connection, reducing the risk of the second connection coming loose.

[0068] In some embodiments, the fourth interface connects the inner surface of the third region to the second location. This directly connects the third region and the second connection, bringing them closer together along the first direction and further reducing the risk of fatigue and cracking in the region located near the second connection of the corner wall.

[0069] In some embodiments, the Vickers hardness of the second transition region is lower than that of the fourth region, and / or the Vickers hardness of the second transition region is lower than that of the second joint. When the Vickers hardness of the second transition region is lower than that of the fourth region, the lower Vickers hardness of the second transition region can be connected to the second joint, easing the stiffness tension between the second joint and the corner wall when the corner wall deforms, and reducing the risk of separation between the corner wall and the second joint. When the Vickers hardness of the second transition region is lower than that of the second joint, the second transition region becomes more deformable than the second joint, easing the stiffness tension between the second joint and the corner wall when the corner wall deforms, and reducing the risk of separation between the corner wall and the second joint.

[0070] In some embodiments, along the first direction, the second connection interface is closer to the fourth region than to the outer surface of the end cap. The second connection can be recessed to a deeper position in the corner wall, effectively improving the connection strength between the corner wall and the end cap.

[0071] In some embodiments, the case includes two first walls and two second walls, the two first walls being positioned opposite each other along a second direction, and the two second walls being positioned opposite each other along a third direction, with the first, second, and third directions being perpendicular in pairs. The case has a nearly rectangular parallelepiped shape, which allows for a larger case size and is advantageous in meeting the requirements for high capacity of the battery cells.

[0072] In some embodiments, the Vickers hardness of at least a portion of the first region is lower than that of the second region. When the second region deforms under the expansion force of the electrode assembly, the region in the first region with a lower Vickers hardness than the second region reduces the impact of the deformation of the second region on the region located near the first connection of the first wall, thereby reducing the risk of the region located near the first connection of the first wall fatigue and cracking due to the expansion of the electrode assembly.

[0073] In some embodiments, along a first direction, the first wall has a position-restricting surface facing the end cap, which abuts against the end cap and restricts the end cap from moving toward the electrode assembly. The position-restricting surface acts as a position-restricting force on the end cap, reducing the risk of the end cap moving toward the electrode assembly when welding to the case, effectively improving the weld quality between the end cap and the case, and reducing the difficulty of welding the end cap and the case.

[0074] In some embodiments, the first wall further includes a position-restricting region installed on the position-restricting surface, the position-restricting region being positioned opposite the end cap along a second direction, and the position-restricting region being welded to the end cap to form a first connection. The position-restricting region can also perform a position-restricting effect on the end cap, reducing the risk of movement along the thickness direction of the first wall when welding the end cap to the case, further improving the weld quality between the end cap and the case, and reducing the difficulty of welding the end cap to the case.

[0075] In some embodiments, the electrode assembly has a laminated structure, and the electrode assembly includes a plurality of positive electrode plates and a plurality of negative electrode plates, which are stacked and installed along a second direction. The laminated electrode assembly has a more compact structure and relatively high pressure resistance.

[0076] In some embodiments, the number of negative electrodes is greater than the number of positive electrodes, and one positive electrode is placed between two adjacent negative electrodes.

[0077] In some embodiments, a negative electrode tab is provided on each negative electrode plate and / or a positive electrode tab is provided on each positive electrode plate.

[0078] In some embodiments, along the third direction, the size of the first region is larger than the size of the positive electrode plate and / or the negative electrode plate, and the first, second, and third directions are perpendicular to each other in pairs. Increasing the size of the first region along the third direction reinforces the strength of more areas of the first wall along the third direction, further reducing the risk of fatigue and cracking of areas located near the first connection point of the first wall.

[0079] In some embodiments, the battery cell further includes two electrode terminals, the two electrode terminals mounted on an end cap, the two electrode terminals having opposite polarities and both electrically connected to an electrode assembly, with a lead hole provided in the end cap, and the electrode terminals include a terminal body, a first position regulating portion and a second position regulating portion, the terminal body being connected to the first and second position regulating portions, the terminal body being drilled into the lead hole, the first position regulating portion located on one side away from the electrode assembly of the end cap along a first direction, and the second position regulating portion located on one side facing the electrode assembly of the end cap. Electrode terminals of this structure can be attached to the end cap by crimping, which is easy to install and offers better cost-effectiveness.

[0080] According to a second aspect, an embodiment of the present application provides a battery which includes a battery cell according to any one embodiment of the first aspect.

[0081] According to a third aspect, an embodiment of the present application provides a power-consuming device including a battery cell according to any one embodiment of the first aspect, the battery cell being used to provide electrical energy to the power-consuming device. [Brief explanation of the drawing]

[0082] To more clearly illustrate the technical concept of the embodiments of this application, the following is a brief introduction to the drawings that may be used in the embodiments. It should be understood that these drawings only illustrate a few embodiments of this application and should not be considered limiting to the scope. Those skilled in the art can, without any creative effort, obtain other relevant drawings based on these. [Figure 1] This is a schematic diagram of the structure of a vehicle according to several embodiments of this application. [Figure 2] This is an exploded view of a battery according to some embodiments of this application. [Figure 3] This is an exploded view of a battery cell according to some embodiments of this application. [Figure 4] Figure 3 is a perspective view of the battery cell. [Figure 5] Figure 4 is a cross-sectional view of the battery cell AA. [Figure 6] This is a magnified view of area B in Figure 5. [Figure 7] Figure 5 is a perspective view of the case shown. [Figure 8] This is a perspective view of an electrode assembly according to several embodiments of this application. [Figure 9] Figure 8 is a schematic diagram of the electrode assembly structure. [Figure 10] This is a perspective view of an electrode assembly according to some other embodiments of this application. [Figure 11] Figure 10 is a schematic diagram of the electrode assembly structure. [Figure 12] Figure 6 shows a partial view of the first wall. [Figure 13] This is a perspective view of a case according to several embodiments of this application. [Figure 14] This is a plan view of the case shown in Figure 13. [Figure 15] This is a perspective view of a case according to several other embodiments of this application. [Figure 16]This is a plan view of the case shown in Figure 15. [Figure 17] This is a perspective view of a case according to several other embodiments of this application. [Figure 18] This is a plan view of the case shown in Figure 17. [Figure 19] This is a partial diagram of a battery cell according to some embodiments of this application (showing the positive electrode plate, negative electrode plate, and separator member of the electrode assembly). [Figure 20] This diagram shows the relative positions of the positive electrode plate, negative electrode plate, and separator member according to some embodiments of this application. [Figure 21] This diagram shows the relative positions of the positive electrode plate, negative electrode plate, and separator member according to some other embodiments of this application. [Figure 22] This is a partial diagram of a battery cell according to some embodiments of this application (showing the first wall). [Figure 23] Figure 22 shows a partial view of the first wall. [Figure 24] Figure 22 is a perspective view of the case shown. [Figure 25] This is a partial diagram of a battery cell according to some other embodiments of this application (showing the first wall). [Figure 26] This is a magnified view of area C in Figure 25. [Figure 27] This is a partial diagram of a battery cell according to several other embodiments of this application (showing the first wall). [Figure 28] This is a magnified view of section D in Figure 27. [Figure 29] This is a partial diagram of a battery cell according to some further embodiments of this application (showing the first wall). [Figure 30] This is a magnified view of area E in Figure 29. [Figure 31] This is a perspective view of a case according to some further embodiments of the present application. [Figure 32] This is a magnified view of area F in Figure 31. [Figure 33] This is a partial view (showing a corner wall) of a battery cell according to some embodiments of this application. [Figure 34] This is a schematic diagram of the structure of a corner wall according to some embodiments of this application. [Figure 35] This is a schematic diagram of the structure of a corner wall according to some other embodiments of this application. [Figure 36] This is a partial view (showing a corner wall) of a battery cell according to some other embodiments of this application. [Figure 37] This is a magnified view of area G in Figure 36. [Figure 38] This is a partial view (showing a corner wall) of a battery cell according to several other embodiments of this application. [Figure 39] This is a magnified view of area H in Figure 38. [Figure 40] This is a partial view (showing a corner wall) of a battery cell according to some further embodiments of this application. [Figure 41] This is a magnified view of area I in Figure 40. [Figure 42] This diagram shows the positional relationship between the end cap and the side wall before welding in some embodiments of this application. [Figure 43] This is a schematic diagram of the connection between the end cap and the electrode terminal according to some embodiments of this application. [Modes for carrying out the invention]

[0083] To clarify the purpose, technical proposal, and advantages of the embodiments of this application, the following clearly describes the technical proposal in the embodiments of this application, linking it with the drawings of the embodiments. Clearly, the embodiments described are only some, not all, embodiments of this application. All other embodiments derived from the embodiments of this application without the creative effort of a person skilled in the art are all within the scope of protection of this application.

[0084] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as that commonly understood by those skilled in the art relating to this application. In this application, terms used in the specification are solely for the purpose of describing specific embodiments and are not intended to limit this application. The terms “includes” and “have,” and any variations thereof, in the description of the specification, claims, and drawings of this application are intended to intentionally cover the non-exclusive “includes.” Terms such as “first,” “second,” etc., in the specification, claims, or drawings of this application are not intended to describe a particular order or hierarchical relationship, but to distinguish different subjects.

[0085] The “Examples” as used in this application mean that certain features, structures, or characteristics described in conjunction with the Examples may be included in at least one Example of this application. The occurrence of this phrase in each location in the specification does not necessarily refer to the same Example, nor does it mean that each Example is mutually exclusive or alternative to the others.

[0086] In this application, the terms "and / or" merely describe the relationship between related objects, indicating that three relationships are possible. For example, A and / or B may represent three cases: A alone, a combination of A and B, or B alone. In this application, the character " / " generally indicates that the preceding and succeeding related objects are in an "or" relationship.

[0087] In the embodiments of this application, the same reference numerals indicate the same component, and for the sake of brevity, detailed descriptions of the same component are omitted in different embodiments. It should be understood that the dimensions such as thickness, aspect ratio of various components in the embodiments of this application shown in the drawings, and the dimensions such as thickness, aspect ratio of the overall assembly device, are illustrative only and do not constitute any limitation of this application.

[0088] As used in this application, "multiple" refers to two or more (including two).

[0089] In the embodiments of this application, the battery cell may be a secondary battery, which is a battery cell that can be used continuously by activating the active material through a charging method after the battery cell has been discharged.

[0090] Battery cells may include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0091] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator member. During charging and discharging of the battery cell, active ions (e.g., lithium ions) intermittently

[0092] In some embodiments, the positive electrode may be a positive electrode plate, and the positive electrode plate may include a positive electrode current collector and a positive electrode active material placed on at least one surface of the positive electrode current collector.

[0093] For example, a positive electrode current collector has two opposing surfaces in the thickness direction of itself, and the positive electrode active material is placed on one or both of the two opposing surfaces of the positive electrode current collector.

[0094] For example, the positive electrode current collector may be a metal foil sheet or a composite current collector. For example, as the metal foil sheet, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy) on a polymer material substrate (for example, a substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0095] For example, the positive electrode active material may include at least one of lithium-containing phosphates, lithium transition metal oxides, and their respective reformed compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may be used. These positive electrode active materials may be used individually or in combination of two or more. Here, examples of lithium-containing phosphates include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which may be abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), composite materials of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides include lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 (It can also be abbreviated as LiNi) 0.5 Co 0.2 Mn 0.3 O2(NCM 523(It can also be abbreviated as LiNi) 0.5 Co 0.25 Mn 0.25 O2(NCM 211 (It can also be abbreviated as LiNi) 0.6 Co 0.2 Mn 0.2 O2(NCM 622 (It can also be abbreviated as LiNi) 0.8 Co 0.1 Mn 0.1 O2(NCM 811 (This can also be abbreviated as LiNi) Lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05 It may contain, but is not limited to, at least one of O2 and its modified compounds.

[0096] In some embodiments, the positive electrode may be made of foamed metal. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. When foamed metal is used as the positive electrode, the positive electrode active material may or may not be placed on the surface of the foamed metal. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the foamed metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[0097] In some embodiments, the negative electrode may be a negative electrode plate, and the negative electrode plate may include a negative electrode current collector.

[0098] For example, the negative electrode current collector may be a metal foil sheet, foamed metal, or a composite current collector. For example, as the metal foil sheet, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium may be used. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, or foamed alloy. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (such as copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys) on a polymer material base (for example, a base material such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0099] For example, the negative electrode plate may include a negative electrode current collector and a negative electrode active material placed on at least one surface of the negative electrode current collector.

[0100] For example, the negative electrode current collector has two opposing surfaces in the thickness direction of itself, and the negative electrode active material is placed on one or both of the two opposing surfaces of the negative electrode current collector.

[0101] For example, the negative electrode active material can be a negative electrode active material used in battery cells known in the art. For example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of elemental silicon, silicon oxygen compounds, silicon carbon composites, silicon nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin acid compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may be used. These negative electrode active materials may be used individually or in combination of two or more.

[0102] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0103] In some embodiments, the separator member is a separator. The separator may be any known porous structure separator having good chemical and mechanical stability.

[0104] For example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multilayer composite film. If the separator is a multilayer composite film, the materials of each layer may be the same or different. The separator member may be a single member located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0105] In some embodiments, the separator component is a solid electrolyte. The solid electrolyte is placed between the positive and negative electrodes and simultaneously performs the functions of ion transport and separation of the positive and negative electrodes.

[0106] In some embodiments, the battery cell further includes an electrolyte that plays a role in conducting ions between the positive and negative electrodes. The electrolyte may be liquid, gel-like, or solid. Here, a liquid electrolyte comprises an electrolyte salt and a solvent.

[0107] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bistrifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium bis(oxalato)borate, lithium difluorobis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0108] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, ethyl methyl sulfone, and diethyl sulfone. The solvent is selectively an ether-based solvent. The ether-based solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0109] Here, the gel-like electrolyte includes a polymer-based skeletal network and is combined with an ionic liquid-lithium salt.

[0110] Here, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0111] For example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymer, polyionic liquid lithium salt, cellulose, etc.

[0112] For example, inorganic solid electrolytes may include one or more of oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfur, argyrodite), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0113] For example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to a polymer solid electrolyte.

[0114] In some embodiments, the electrode assembly is a wound structure. The positive electrode plate and the negative electrode plate are wound into the wound structure.

[0115] In some embodiments, the electrode assembly has a layered structure.

[0116] For example, multiple positive and negative electrodes may be installed, and the multiple positive and negative electrodes may be stacked alternately.

[0117] For example, multiple positive electrode plates may be installed, and the negative electrode plates may be folded and stacked to form multiple folded segments, with one positive electrode plate sandwiched between adjacent folded segments.

[0118] For example, both the positive and negative electrode plates are folded and stacked to form multiple folded segments.

[0119] For example, multiple separator members may be installed, each placed between any adjacent positive or negative electrode plates.

[0120] For example, the separator members may be installed continuously, or they may be installed between any adjacent positive or negative electrode plates by folding or winding them.

[0121] In some embodiments, the shape of the electrode assembly may be cylindrical, flattened, or polygonal prism-shaped, etc.

[0122] In some embodiments, the electrode assembly is provided with tabs from which current can be drawn from the electrode assembly. The tabs include a positive electrode tab and a negative electrode tab.

[0123] In some embodiments, the battery cell may include a housing. The housing may be used to package components such as electrode assemblies and electrolytes. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., copper-aluminum composite housing), or an aluminum-plastic film.

[0124] For example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shape. The prismatic battery cell includes prismatic battery cells, blade-shaped battery cells, and polygonal prismatic battery cells, and a polygonal prismatic battery cell is, for example, a hexagonal prismatic battery cell.

[0125] The batteries referred to in the embodiments of this application refer to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0126] In some embodiments, the battery may be a battery module, and if there are multiple battery cells, the multiple battery cells are arranged and fixed to form a single battery module.

[0127] In some embodiments, the battery may be a battery pack, which includes a housing and battery cells, and the battery cells or battery modules are housed within the housing.

[0128] In some embodiments, the housing can be part of the vehicle's chassis structure. For example, the housing may be part of at least the vehicle's floor, or it may be part of at least the vehicle's cross members and side members.

[0129] In some embodiments, the battery may be an energy storage device. The energy storage device may include an energy storage container, an energy storage electrical cabinet, and the like.

[0130] In related technologies, a battery cell generally includes a housing and an electrode assembly, the housing may include a case and an end cap, the case having an opening, and after the electrode assembly is assembled into the case, the opening of the case can be sealed with the end cap to form a sealed space inside the housing that accommodates the electrode assembly.

[0131] To ensure a stable connection between the end cap and the case, the end cap and the case may be welded together. After the end cap and the case are welded together, a connection is formed at the welded location between the end cap and the case. Due to the high temperature of the welding, a heat-affected zone is formed in the area of ​​the case wall near the connection, and the strength of the part of the case wall located within the heat-affected zone is reduced.

[0132] During the charge-discharge cycle of a battery cell, the electrode assembly expands, and the case wall deforms after being subjected to the expansion force of the electrode assembly. If this continues for a long time, the area near the connection point of the case wall (the heat-affected zone) becomes fatigued and prone to cracking, affecting the lifespan of the battery cell.

[0133] Based on the above considerations, in order to mitigate the problem of fatigue and cracking in areas located near the connection of the case wall, embodiments of the present application provide a battery cell including a case, an end cap, and an electrode assembly. The case has an opening at least one end along a first direction, the case includes a first wall, the end cap seals the opening, and the first wall is welded to the end cap to form a first connection. The electrode assembly is at least partially housed within the case, and the electrode assembly includes a positive electrode plate and a negative electrode plate, at least a portion of the positive electrode plate and at least a portion of the negative electrode plate are stacked along a second direction, the second direction being parallel to the thickness direction of the first wall, and the first direction intersecting the second direction. The first wall includes a first region and a second region arranged along the first direction, the thickness of the first region being greater than the thickness of the second region, and the first region being located between the first connection and the second region.

[0134] In such a battery cell, the thickness of the first region is greater than the thickness of the second region, and the first region is located between the first connection and the second region. As a result, the thicker first region is closer to the first connection than the second region, and the first region acts as a reinforcement to the region of the first wall located near the first connection, reducing the risk of the region of the first wall near the first connection becoming fatigued and cracking due to the expansion of the electrode assembly, and further improving the service life of the battery cell.

[0135] The battery cells described in the embodiments of this application can be applied to batteries and power-consuming devices that use battery cells.

[0136] Power-consuming devices may include vehicles, mobile phones, portable devices, laptop computers, steamships, spacecraft, electric toys, and power tools. Vehicles may be fuel-oil vehicles, gas vehicles, or new energy vehicles, and new energy vehicles may be pure electric vehicles, hybrid vehicles, or range-extender vehicles. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators, and electric planers. The embodiments of this application do not particularly limit the power-consuming devices described above.

[0137] In the following embodiments, for the sake of explanation, we will use a vehicle as an example of the power-consuming device.

[0138] Referring to Figure 1, Figure 1 is a schematic diagram of the structure of a vehicle 1000 according to some embodiments of the present application. A battery 100 is installed inside the vehicle 1000, and the battery 100 may be installed at the bottom, head, or tail of the vehicle 1000. The battery 100 may be used to supply power to the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000.

[0139] The vehicle 1000 may further include a controller 200 and a motor 300, the controller 200 being used to control the battery 100 to supply power to the motor 300, for example, to meet the power consumption requirements for starting the vehicle 1000, navigation, and driving.

[0140] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but can also serve as the driving power source for the vehicle 1000, providing driving power to the vehicle 1000 in place of or in place of fuel oil or natural gas.

[0141] Referring to Figure 2, which is an exploded view of a battery 100 according to some embodiments of the present application, the battery 100 includes a battery cell 10 and a housing 20, the battery cell 10 being housed within the housing 20.

[0142] Here, the housing 20 is a component that houses the battery cell 10, and the housing 20 provides a housing space for the battery cell 10, and the housing 20 may employ various structures. In some embodiments, the housing 20 may include a first housing 201 and a second housing 202, and the first housing 201 and the second housing 202 are placed over each other to define a housing space for housing the battery cell 10. The first housing 201 and the second housing 202 may have various shapes, for example, a rectangular parallelepiped, a cylindrical shape, etc. The first housing 201 may be a hollow structure with one side open, and the second housing 202 may be a hollow structure with one side open, and the open side of the second housing 202 is placed over the open side of the first housing 201 to form a housing 20 having a housing space. The first housing 201 may be a hollow structure with one side open, and the second housing 202 may be a plate-like structure. The second housing 202 is placed over the open side of the first housing 201 to form a housing 20 having a storage space. The first housing 201 and the second housing 202 may be sealed via a sealing element, which may be a sealing ring, sealant, or the like.

[0143] In the battery 100, there may be one battery cell 10 or multiple battery cells 10. When there are multiple battery cells 10, the multiple battery cells 10 may be connected in series, in parallel, or in series-parallel, where series-parallel connection means that there are both series and parallel connections among the multiple battery cells 10. Multiple battery cells 10 may first be connected in series, in parallel, or in series-parallel to form a battery module, and then the multiple battery modules may be connected in series, in parallel, or in series-parallel to form a single whole and housed in the housing 20. All battery cells 10 may be connected directly in series, in parallel, or in series-parallel as a single unit, and then the whole composed of all battery cells 10 may be housed in the housing 20.

[0144] Referring to Figures 3 and 4, Figure 3 is an exploded view of a battery cell 10 according to some embodiments of the present application, and Figure 4 is a perspective view of the battery cell 10 shown in Figure 3. The battery cell 10 may include a housing 1 and an electrode assembly 2, the electrode assembly 2 being housed within the housing 1.

[0145] In some embodiments, the housing 1 may include a case 11 and an end cap 12, the case 11 having an opening, and the end cap 12 sealing the opening of the case 11.

[0146] The case 11 is a component for housing the electrode assembly 2. The case 11 may be a hollow structure with an opening at one end, or it may be a hollow structure with openings at both opposing ends. The case 11 may have various shapes, such as cylindrical or rectangular parallelepiped. The material of the case 11 may vary, such as copper, iron, aluminum, steel, or aluminum alloy. The electrode assembly 2 may be partially or entirely located inside the case 11.

[0147] The end cap 12 is a component that closes the opening of the case 11, separating the internal environment of the battery cell 10 from the external environment. The end cap 12 and the case 11 together define a storage space for housing the electrode assembly 2, electrolyte, and other components. The end cap 12 may be connected to the case 11 by welding or roll sealing to seal the opening of the case 11. The shape of the end cap 12 can be adapted to the shape of the case 11. For example, if the case 11 has a rectangular parallelepiped structure, the end cap 12 may have a rectangular plate-like structure that can be adapted to the case 11. Alternatively, if the case 11 has a cylindrical structure, the end cap 12 may have a circular plate-like structure that can be adapted to the case 11. The material of the end cap 12 can vary and may be copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 12 may be the same as or different from the material of the case 11.

[0148] In embodiments where the case 11 has an opening at one end, one end cap 12 may be installed. In embodiments where the case 11 has openings at both opposing ends, two end caps 12 may be installed, each sealing two openings in the case 11, and together with the case 11, the two end caps 12 define the storage space.

[0149] In some embodiments, the battery cell 10 may further include electrode terminals 3, which are mounted on the housing 1 and electrically connected to tabs 21 of the electrode assembly 2 to be used to input or output electrical energy to the battery cell 10. The electrode terminals 3 may be mounted on the case 11 of the housing 1 or on the end cap 12 of the housing 1. The electrode terminals 3 and tabs 21 may be directly connected, for example, by welding. The electrode terminals 3 and tabs 21 may be indirectly connected, for example, by a current collector. The current collector may be a metal conductor, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0150] In some embodiments, the battery cell 10 may further include a pressure release mechanism 4, which may be installed on an end cap 12, or the case 11 may be installed on the pressure release mechanism 4. The pressure release mechanism 4 may be a pressure release member attached to the case 11 or end cap 12, for example, an explosion-proof sheet, a safety valve, etc. The pressure release mechanism 4 may be integrally molded with the end cap 12 or the case 11. The pressure release mechanism 4 may have a pressure release groove installed so that it tears along the pressure release groove when the battery cell 10 is pressure released. The pressure release groove may be a groove extending along a sealed trajectory, which may be a circular trajectory, a rectangular trajectory, etc. The pressure release groove may be a groove extending along an unsealed trajectory, which may be an H-shaped trajectory, a Y-shaped trajectory, a V-shaped trajectory, a U-shaped trajectory, etc.

[0151] For example, as shown in Figures 3 and 4, an opening is formed at one end of the case 11, and there is one end cap 12 in the housing 1, which seals one of the openings in the case 11. A pressure relief mechanism 4 is installed on the end cap 12, and two electrode terminals 3 are installed on the end cap 12, the two electrode terminals 3 being a positive electrode terminal and a negative electrode terminal, respectively, and a positive electrode tab 21a and a negative electrode tab 21b are formed at one end of the electrode assembly 2 facing the end cap 12, the positive electrode terminal is electrically connected to the positive electrode tab 21a and the negative electrode terminal is electrically connected to the negative electrode tab 21b.

[0152] Referring to Figures 5-7, Figure 5 is a cross-sectional view AA of the battery cell 10 shown in Figure 4, Figure 6 is a partial enlarged view of location B in Figure 5, and Figure 7 is a perspective view of the case 11 shown in Figure 5. Embodiments of the present application provide a battery cell 10 including a case 11, an end cap 12, and an electrode assembly 2. At least one end of the case 11 along a first direction Z has an opening, the case 11 includes a first wall 111, the end cap 12 seals the opening, and the first wall 111 is welded to the end cap 12 to form a first connection 51. The electrode assembly 2 is at least partially housed in the case 11, and the electrode assembly 2 includes a positive electrode plate 22 and a negative electrode plate 23, at least a portion of the positive electrode plate 22 and at least a portion of the negative electrode plate 23 are stacked along a second direction Y, the second direction Y is parallel to the thickness direction of the first wall 111, and the first direction Z intersects the second direction Y. The first wall 111 includes a first region 1111 and a second region 1112 arranged along a first direction Z, the thickness of the first region 1111 being greater than the thickness of the second region 1112, and the first region 1111 being located between the first connection 51 and the second region 1112.

[0153] An opening may be formed at only one end of the case 11 along the first direction Z, and one end cap 12 may be installed accordingly. Alternatively, openings may be formed at both opposing ends of the case 11 along the first direction Z, and two end caps 12 may be installed accordingly. The case 11 may be of various shapes, such as cylindrical or prismatic. A prismatic case may be a triangular prism, a square prism, a pentagonal prism, a hexagonal prism, etc., and a square prism may be a rectangular parallelepiped, a cube, etc. The first direction Z is parallel to the direction of the opening of the case 11. In embodiments where the case 11 is cylindrical, the first direction Z may be parallel to the axial direction of the case 11. In embodiments where the case 11 is prismatic, the first direction Z may be parallel to the extension direction of the side edge of the case 11. The second direction Y is parallel to the thickness direction of the first wall 111. In embodiments where case 11 is cylindrical, the first wall 111 is cylindrical, the radial direction of case 11 is the thickness direction of the first wall 111, and the second direction Y is parallel to the radial direction of case 11. In embodiments where case 11 is prismatic, the first wall 111 may be a rectangular plate structure. The first direction Z and the second direction Y may be set at an acute angle, a right angle, or an obtuse angle.

[0154] The end cap 12 may be welded to the case 11, or the end cap 12 and the case 11 may be welded together to form a connection portion 5, and the connection portion 5 may extend along the circumferential direction of the opening of the case 11. The end cap 12 and the case 11 are connected and fixed via the connection portion 5, thereby achieving a seal between the end cap 12 and the case 11. The connection portion 5 is the portion where a weld mark is formed after the end cap 12 and the case 11 are welded together, and the connection portion 5 may be the portion where the end cap 12 and the case 11 are welded together and fused as one unit.

[0155] In case 11, the first wall 111 may be one or multiple. The first connection portion 51 may correspond one-to-one with the first wall 111, and the first connection portion 51 may be the portion where a weld mark is formed after the end cap 12 and the first wall 111 are welded together, or the portion where the end cap 12 and the first wall 111 are welded together and fused as one. Part of the first connection portion 51 is formed on the end cap 12, and the other part of the first connection portion 51 is formed on the first wall 111. The first wall 111 and the end cap 12 may form the first connection portion 51 by overlap seam welding or by through welding. The first connection portion 51 may be part of the connection portion 5 or all of the connection portion 5. In the embodiment where case 11 is cylindrical, there is only one first wall 111 in case 11, the first wall 111 is cylindrical, and the first connecting portion 51 is the connecting portion 5. In the embodiment where case 11 is prismatic, case 11 may include a plurality of side walls, the plurality of side walls are installed along the opening of case 11, and at least one of the two side walls installed opposite each other along a second direction Y may be the first wall 111, and the first connecting portion 51 is part of the connecting portion 5.

[0156] The first wall 111 may be the wall with the largest outer surface area in case 11, or it may not be the wall with the largest outer surface area in case 11. For example, case 11 may be a rectangular parallelepiped, and case 11 may include two first walls 111 and two second walls 112, the two first walls 111 being installed opposite each other along a second direction Y, and the two second walls 112 being installed opposite each other along a third direction X, the first direction Z, the second direction Y and the third direction X being perpendicular in pairs, the first wall 111 may be the wall with the largest outer surface area in case 11, and the outer surface area of ​​the first wall 111 is made larger than the outer surface area of ​​the second wall 112, and the second wall 112 may be the wall with the largest outer surface area in case 11, and the outer surface area of ​​the second wall 112 is made larger than the outer surface area of ​​the first wall 111.

[0157] The first region 1111 may be a region where the thickness of the first wall 111 is increased, and the first region 1111 may be thicker than the second region 1112, and the second region 1112 may be a portion located on one side of the first region 1111 away from the first connection portion 51 along the first direction Z of the first wall 111. The first region 1111 and the first connection portion 51 may be directly connected or indirectly connected, and the first region 1111 and the second region 1112 may be directly connected or indirectly connected. The first region 1111 may have a uniform thickness structure or a non-uniform thickness structure, and the second region 1112 may have a uniform thickness structure or a non-uniform thickness structure. If at least one of the first region 1111 and the second region 1112 has a non-uniform thickness structure, the maximum thickness of the second region 1112 may be less than or equal to the minimum thickness of the first region 1111, thereby achieving that the thickness of the first region 1111 is greater than the thickness of the second region 1112.

[0158] The second region 1112 has a first inner surface 11121 facing the internal space of the case 11 and a first outer surface 11122 away from the internal space of the case 11, and the first region 1111 may have a portion protruding from the first inner surface 11121 and / or the first outer surface 11122. For example, in the embodiment shown in Figure 6, a portion of the first region 1111 protrudes from the first inner surface 11121, and the outer surface of the first region 1111 is coplanar with the first outer surface 11122.

[0159] The electrode assembly 2 is located within the housing space defined by the case 11 and the end cap 12. The electrode assembly 2 may have a stacked structure or a wound structure. There may be one electrode assembly 2 in the case 11 or multiple electrode assemblies 2. If there are multiple electrode assemblies 2, the multiple electrode assemblies 2 may be stacked and installed, for example, the multiple electrode assemblies 2 may be stacked and installed along a second direction Y.

[0160] At least a portion of the positive electrode plate 22 and at least a portion of the negative electrode plate 23 are stacked and installed along a second direction Y, and the electrode assembly 2 expands along the second direction Y during the cycle process, and the first wall 111 deforms after being subjected to the expansion force of the electrode assembly 2, and the region of the first wall 111 located near the first connection portion 51 is prone to fatigue and cracking. In this application, the thickness of the first region 1111 is set to be greater than the thickness of the second region 1112, and the first region 1111 is set between the first connection portion 51 and the second region 1112, so that the thicker first region 1111 is closer to the first connection portion 51 than the second region 1112, the first region 1111 provides a certain reinforcing effect to the region of the first wall 111 located near the first connection portion 51, reduces the risk of the region of the first wall 111 located near the first connection portion 51 being fatigued and cracked due to the expansion of the electrode assembly 2, and further improves the service life of the battery cell 10.

[0161] In some embodiments, referring to Figures 8-11, Figure 8 is a perspective view of an electrode assembly 2 according to some embodiments of the present application, Figure 9 is a schematic diagram of the structure of the electrode assembly 2 shown in Figure 8, Figure 10 is a perspective view of an electrode assembly 2 according to some other embodiments of the present application, and Figure 11 is a schematic diagram of the structure of the electrode assembly 2 shown in Figure 10. The electrode assembly 2 has a flat region 25, and the portions of the positive electrode plate 22 located in the flat region 25 and the portions of the negative electrode plate 23 located in the flat region 25 are stacked and installed along a second direction Y.

[0162] The flat region 25 is the flat portion of the electrode assembly 2, and the portion of the positive electrode plate 22 located in the flat region 25 is substantially flat, and the portion of the negative electrode plate 23 located in the flat region 25 is substantially flat. For example, both the portion of the positive electrode plate 22 located in the flat region 25 and the portion of the negative electrode plate 23 located in the flat region 25 are flat plate structures. If the electrode assembly 2 has a wound structure, the electrode assembly 2 is a wound electrode assembly, and a part of the electrode assembly 2 may be the flat region 25. If the electrode assembly 2 has a laminated structure, the electrode assembly 2 is a laminated electrode assembly, and the entire electrode assembly 2 may be the flat region 25. The second direction Y is the lamination direction of the portion of the positive electrode plate 22 located in the flat region 25 and the portion of the negative electrode plate 23 located in the flat region 25.

[0163] For example, the electrode assembly 2 may further include a separator member 24, which is placed between the positive electrode plate 22 and the negative electrode plate 23, and is used to separate the positive electrode plate 22 and the negative electrode plate 23. The portions of the positive electrode plate 22 located in the flat region 25, the portions of the negative electrode plate 23 located in the flat region 25, and the portions of the separator member 24 located in the flat region 25 are stacked and installed along the second direction Y.

[0164] The second direction Y is the stacking direction of the portion of the positive electrode plate 22 located in the flat region 25 and the portion of the negative electrode plate 23 located in the flat region 25. The amount of expansion of the electrode assembly 2 along the second direction Y during the cycle process is greater, and the first wall 111 is more affected by the expansion of the electrode assembly 2. However, the first region 1111 acts as a reinforcement to the region of the first wall 111 located near the first connection portion 51, thereby reducing the risk of the first wall 111 fatigue and cracking near the first connection portion 51 due to the expansion of the electrode assembly 2.

[0165] In some embodiments, referring again to Figures 8-11, the electrode assembly 2 includes adjacent first surface 27 and second surface 28, the first surface 27 being perpendicular to the second direction Y, the area of ​​the first surface 27 being larger than the area of ​​the second surface 28, and the first surface 27 and the first wall 111 being positioned opposite each other along the second direction Y.

[0166] The first surface 27 is the outer surface of the electrode assembly 2 perpendicular to the second direction Y, and the second surface 28 is the outer surface of the electrode assembly 2 adjacent to the first surface 27. The first surface 27 is installed facing the first wall 111 along the second direction Y. The first surface 27 may be a plane, and may be the surface with the largest area among the outer surfaces of the electrode assembly 2, or it may not be the surface with the largest area among the outer surfaces of the electrode assembly 2. The second surface 28 may be a plane, or it may be at least partially an arcuate surface. It should be noted that the first surface 27 is approximately perpendicular to the second direction Y, and it should also be understood that the first surface 27 is perpendicular to the second direction Y.

[0167] For example, there are two first surfaces 27 and two second surfaces 28, the two first surfaces 27 are positioned opposite each other along the second direction Y, the two second surfaces 28 are positioned opposite each other along the third direction X, the positive electrode tab 21a and negative electrode tab 21b protrude from the surface of the electrode assembly 2 along the first direction Z, the outermost part of the electrode assembly 2 along the second direction Y is a separator member 24, the first surface 27 is formed on the separator member 24, and the first direction Z, the second direction Y and the third direction X are perpendicular in pairs.

[0168] In this embodiment, the area of ​​the first surface 27 is larger than the area of ​​the second surface 28, thereby resulting in a greater expansion force on the first wall 111, which is installed in the case 11 facing the first surface 27. The first region 1111 provides a reinforcing effect on the region of the first wall 111 located near the first connection portion 51, thereby reducing the risk of the first wall 111 fatigue and cracking near the first connection portion 51 due to the expansion of the electrode assembly 2.

[0169] In some embodiments, the first surface 27 is the largest surface area of ​​the outer surface of the electrode assembly 2.

[0170] It should be explained that the first surface 27 is the largest surface on the outer surface of the electrode assembly 2, and this does not limit the number of first surfaces 27 in the electrode assembly 2 to just one. To be clear, the first surface 27 of the electrode assembly 2 may be one or two.

[0171] For example, in the embodiment shown in Figure 8, the electrode assembly 2 has a wound structure, is flattened, includes six surfaces, and of the six surfaces, the two surfaces that are positioned opposite each other along the second direction Y have the largest area, and these two surfaces are both the first surface 27. In the embodiment shown in Figure 10, the electrode assembly 2 has a laminated structure, is approximately rectangular, includes six surfaces, and of the six surfaces, the two surfaces that are positioned opposite each other along the second direction Y have the largest area, and these two surfaces are both the first surface 27.

[0172] In this embodiment, the first surface 27 is the largest surface area of ​​the outer surface of the electrode assembly 2, and as a result, the first wall 111, which is installed in the case 11 facing the first surface 27, experiences the greatest expansion force. The first region 1111 provides a reinforcing effect to the region of the first wall 111 located near the first connection portion 51, thereby reducing the risk of the first wall 111 fatigue and cracking near the first connection portion 51 due to the expansion of the electrode assembly 2.

[0173] In some embodiments, referring to Figures 8 and 9, the electrode assembly 2 is a wound structure, and the electrode assembly 2 further has a corner region 26, which is located at least one end of the flat region 25 along a third direction X, and the first direction Z, the second direction Y and the third direction X are not coplanar and intersect two at a time. The outer surface of the flat region 25 includes a first surface 27, and the outer surface of the corner region 26 includes a second surface 28, at least a portion of which is an arcuate surface.

[0174] The flat region 25 may have a corner region 26 at only one end along the third direction X, or corner regions 26 may be provided at both opposing ends along the third direction X. The three directions, the first direction Z, the second direction Y, and the third direction X, are not on the same plane, and any two of the first direction Z, the second direction Y, and the third direction X may be set at an acute angle, a right angle, or an obtuse angle. The first surface 27 may be part of the outer surface of the flat region 25, the second surface 28 may be part of the outer surface of the corner region 26, and the second surface 28 may be entirely an arcuate surface, or only a part of it may be an arcuate surface.

[0175] For example, the positive electrode plate 22, the separator member 24, and the negative electrode plate 23 are stacked and then wound to form a wound structure. The first direction Z, the second direction Y, and the third direction X are perpendicular to each other in pairs, and corner regions 26 are provided at both ends of the flat region 25 along the third direction X. The portions of the positive electrode plate 22, the negative electrode plate 23, and the separator member 24 located in the corner regions 26 are curved, and the portion of the positive electrode plate 22 located in the corner region 26 may be at least partially arc-shaped, the portion of the negative electrode plate 23 located in the corner region 26 may be at least partially arc-shaped, and the portion of the separator member 24 located in the corner region 26 may be at least partially arc-shaped. Along the winding direction of the electrode assembly 2, the outermost ring of the electrode assembly 2 is the separator member 24, and the first surface 27 and the second surface 28 are both part of the outer surface of the outermost ring of the electrode assembly 2, the first surface 27 is a plane, and the second surface 28 is an arcuate surface, the axis of the arcuate surface extends along the first direction Z. Along the second direction Y, both surfaces on both sides of the flat region 25 are the first surface 27, and along the third direction X, the surface on one side of one corner region 26 away from the other corner region 26 is the first second surface 28, and the surface on one side of the other corner region 26 away from the first corner region 26 is the other second surface 28.

[0176] In the case of a wound electrode assembly, the amount of expansion of the flat region 25 in the second direction Y is greater. The first region 1111 acts as a reinforcement to the region of the first wall 111 located near the first connection 51, thereby effectively reducing the risk of the first wall 111 fatigue and cracking near the first connection 51 due to the expansion of the electrode assembly 2.

[0177] In some embodiments, referring again to Figures 10 and 11, the electrode assembly 2 is a laminated structure, and the flat region 25 includes a plurality of positive electrode plates 22 and a plurality of negative electrode plates 23, the plurality of positive electrode plates 22 and a plurality of negative electrode plates 23 are stacked and arranged along a second direction Y, and the first surface 27 is perpendicular to the second surface 28.

[0178] For example, multiple positive electrode plates 22, multiple negative electrode plates 23, and multiple separator members 24 are stacked and installed along a second direction Y to form a stacked structure. The positive electrode plates 22 and negative electrode plates 23 are located in a completely flat region 25, and separator members 24 are installed between adjacent positive electrode plates 22 and negative electrode plates 23. The separator members 24 extend beyond both ends of the positive electrode plates 22 and both ends of the negative electrode plates 23 along a third direction X, and the protruding portions of multiple separator members 24 are connected to form a single integrated portion, and the second surface 28 is formed on this integrated portion. Along the second direction Y, all positive electrode plates 22 and all negative electrode plates 23 are located between the two outermost separator members 24, and the outer surfaces of these two separator members 24 are both the first surface 27.

[0179] It should be explained that the first surface 27 and the second surface 28 are nearly perpendicular, and that the first surface 27 is perpendicular to the second surface 28. For example, if the angle between the first surface 27 and the second surface 28 is in the range of 85° to 95°, it can be understood that the first surface 27 and the second surface 28 are perpendicular.

[0180] In the case of a wound electrode assembly, the amount of expansion of the positive electrode plate 22 and the negative electrode plate 23 of the electrode assembly 2 in the stacking direction is greater. The first region 1111 provides a reinforcing effect to the region of the first wall 111 located near the first connection 51, thereby effectively reducing the risk of the first wall 111 fatigue and cracking near the first connection 51 due to the expansion of the electrode assembly 2.

[0181] In some embodiments, referring again to Figure 7, the first wall 111 is the wall with the largest outer surface area in case 11.

[0182] It should be explained that the first wall 111 is the wall with the largest outer surface area in case 11, but this does not limit the number of first walls 111 in case 11 to just one. To make it clear, the wall with the largest outer surface area in case 11 may be one or two.

[0183] The wall with the largest outer surface area in case 11 is more prone to deformation after being subjected to the expansion force of the electrode assembly 2, and since the first wall 111 is the wall with the largest outer surface area in case 11, the risk of the wall with the largest outer surface area in case 11 fatigue and cracking near the first connection part 51 due to the expansion of the electrode assembly 2 is reduced.

[0184] In some embodiments, case 11 includes two first walls 111, which are positioned opposite each other along a second direction Y, and electrode assembly 2 (shown in Figure 5) is located between the two first walls 111.

[0185] For example, in the embodiment shown in Figure 7, the case 11 is rectangular in shape and may include two first walls 111 and two second walls 112, the two first walls 111 being positioned opposite each other along a second direction Y, and the two second walls 112 being positioned opposite each other along a third direction X, with the outer surface area of ​​the first walls 111 being larger than the outer surface area of ​​the second walls 112. The first direction Z is parallel to the height direction of the case 11, the second direction Y is parallel to the width direction of the case 11, and the third direction X is parallel to the longitudinal direction of the case 11.

[0186] In this embodiment, the case 11 includes two first walls 111, which reduce the risk of fatigue and cracking near the first connection 51 due to the expansion of the electrode assembly 2.

[0187] In some embodiments, referring to Figure 12, which is a partial view of the first wall 111 shown in Figure 6, the first region 1111 includes a first portion 11111 and a second portion 11112 arranged along a first direction Z, the second portion 11112 connecting the first portion 11111 and the second region 1112, and the thickness of the first portion 11111 is greater than the thickness of the second portion 11112.

[0188] The first portion 11111, the second portion 11112, and the second region 1112 are arranged sequentially along the first direction Z, with the first portion 11111 transitioning to the second region 1112 via the second portion 11112. The first portion 11111 may have a uniform thickness structure or a non-uniform thickness structure, and the second portion 11112 may have a uniform thickness structure or a non-uniform thickness structure. If at least one of the first portion 11111 and the second portion 11112 has a non-uniform thickness structure, the maximum thickness of the second portion 11112 may be less than or equal to the minimum thickness of the first portion 11111, thereby achieving that the thickness of the first portion 11111 is greater than the thickness of the second portion 11112.

[0189] The first portion 11111 may partially protrude from the first inner surface 11121 and / or the first outer surface 11122, and the second portion 11112 may protrude from the first inner surface 11121 and / or the first outer surface 11122.

[0190] The region of the first region 1111 adjacent to the first connection 51 is more prone to forming a heat-affected zone, and this region is more susceptible to fatigue and cracking. However, the second portion 11112 connects the first portion 11111 and the second region 1112, and the thickness of the first portion 11111 is greater than the thickness of the second portion 11112. Therefore, the thicker first portion 11111 in the first region 1111 is brought closer to the first connection 51, effectively reducing the influence of the heat-affected zone on the first region 1111 and lowering the risk of fatigue and cracking in the region of the first wall 111 located near the first connection 51. In addition, because the thickness of the second portion 11112 is less than the thickness of the first portion 11111, the amount of material used in the first region 1111 can be reduced, thereby lowering production costs.

[0191] In some embodiments, the thickness of the second portion 11112 tends to decrease along the direction in which the end cap 12 (not shown in Figure 12) is toward the electrode assembly 2 (not shown in Figure 12).

[0192] The direction in which the end cap 12 faces the electrode assembly 2 coincides with the direction in which the first portion 11111 faces the second region 1112 along the first direction Z.

[0193] To make it clear, the second portion 11112 has a non-uniform thickness structure. For example, the thickness of the second portion 11112 gradually decreases along the direction in which the end cap 12 faces the electrode assembly 2. At least one of the inner and outer surfaces of the second portion 11112 may be a bevel, thereby achieving the gradual decrease in the thickness of the second portion 11112 along the direction in which the end cap 12 faces the electrode assembly 2.

[0194] For example, in the embodiment shown in Figure 12, both the first portion 11111 and the second region 1112 have a uniform thickness structure, the inner and outer surfaces of the first portion 11111 are set parallel to each other, and the first inner surface 11121 and the first outer surface 11122 of the second region 1112 are set parallel to each other. The outer surface of the second portion 11112, the outer surface of the first portion 11111 and the first outer surface 11122 are on the same plane, a portion of the first portion 11111 and a portion of the second portion 11112 both protrude from the first inner surface 11121, and the inner surface of the second portion 11112 is connected to the first inner surface 11121 and the inner surface of the first portion 11111.

[0195] In this embodiment, the thickness of the second portion 11112 tends to decrease along the direction in which the end cap 12 is directed toward the electrode assembly 2. On the one hand, this reduces the influence of the second portion 11112 on the electrode assembly 2 and reduces the risk of interference between the second portion 11112 and the electrode assembly 2. On the other hand, the reinforcing effect of the second portion 11112 tends to increase along the direction in which the electrode assembly 2 is directed toward the end cap 12. This provides a good reinforcing effect even when the region of the second portion 11112 adjacent to the first portion 11111 is affected by the first connection 51, reducing the risk of the first wall 111 fatigue and cracking at the second portion 11112. Furthermore, the second portion 11112 enables a transition between the first portion 11111 and the second region 1112, reducing stress concentration.

[0196] In some embodiments, referring to Figures 13 and 14, Figure 13 is a perspective view of Case 11 according to some embodiments of the present application, and Figure 14 is a plan view of Case 11 shown in Figure 13. The size of the first region 1111 along the third direction X is greater than the size of the first region 1111 along the first direction Z, and the first direction Z, the second direction Y, and the third direction X are not coplanar and intersect in pairs.

[0197] The size of the first region 1111 along the third direction X is the length of the first region 1111, and the size of the first region 1111 along the first direction Z is the width of the first region 1111. The length of the first region 1111 is greater than the width of the first region 1111, and thus the first region 1111 is an elongated structure that extends along the third direction X.

[0198] For example, case 11 is rectangular in shape and includes two first walls 111 and two second walls 112, the two first walls 111 being positioned opposite each other along a second direction Y, and the two second walls 112 being positioned opposite each other along a third direction X, the first direction Z, the second direction Y and the third direction X being perpendicular in pairs, the first direction Z being parallel to the height direction of case 11, the second direction Y being parallel to the width direction of case 11, and the third direction X being parallel to the longitudinal direction of case 11.

[0199] In this embodiment, the size of the first region 1111 along the third direction X is larger than the size of the first region 1111 along the first direction Z, thereby increasing the size of the first region 1111 along the third direction X and reinforcing the strength of more areas of the first wall 111 along the third direction X, further reducing the risk of fatigue and cracking of areas located near the first connection 51 of the first wall 111.

[0200] In some embodiments, the first region 1111 includes a first connecting segment 11113, the first connecting segment 11113 passing through the middle section of the first wall 111, the middle section being perpendicular to a third direction X, and the distance from the middle section to both ends of the first wall 111 being equal along the third direction X.

[0201] The first connecting segment 11113 may be part of the first region 1111, or the first connecting segment 11113 may be the first region 1111. The first connecting segment 11113 may be of equal thickness or non-equal thickness, and the first connecting segment 11113 has opposing ends along the third direction X, and the first connecting segment 11113 passes through the middle section of the first wall 111, so that the middle section of the first wall 111 is located between the opposing ends of the first connecting segment 11113 along the third direction X. The distance from the opposing ends of the first connecting segment 11113 along the third direction X to the middle section may be equal or not. If the distance from the opposing ends of the first connecting segment 11113 along the third direction X to the middle section of the first wall 111 is equal, the first connecting segment 11113 may be a symmetrical structure installed symmetrically with respect to the middle section of the first wall 111. It should be explained that the intermediate section of the first wall 111 is a virtual plane and is not shown in the diagram.

[0202] For example, in the embodiments shown in Figures 13 and 14, the first connecting segment 11113 is the first region 1111, the first connecting segment 11113 has a uniform thickness structure, and the distance from both opposing ends of the first connecting segment 11113 along the third direction X to the middle section of the first wall 111 is equal.

[0203] Taking case 11 as an example, the distance from the middle section of the first wall 111 to both ends of the first wall 111 along the third direction X is equal, that is, the distance from the middle section of the first wall 111 to the two second walls 112 installed opposite each other along the third direction X of case 11 is equal.

[0204] It should be explained that, along the third direction X, the distance from the middle section of the first wall 111 to both ends of the first wall 111 is approximately equal, and it should be understood that the distance from the middle section to both ends of the first wall 111 is equal.

[0205] When the first wall 111 is subjected to the expansion force of the electrode assembly 2 of the battery cell 10, the deformation of the intermediate region of the first wall 111 along the third direction X becomes greater, and the intermediate region of the first wall 111 along the third direction X becomes more fatigued and prone to cracking. Since the first connecting segment 11113 of the first region 1111 passes through the middle section of the first wall 111, the strength of at least the intermediate region of the first wall 111 along the third direction X is reinforced, reducing the risk of the intermediate region of the first wall 111 along the third direction X becoming fatigued and cracking near the first connection 51.

[0206] In some embodiments, Figure 15 is a perspective view of Case 11 according to some other embodiments of the present application, and Figure 16 is a plan view of Case 11 shown in Figure 15. The first region 1111 further includes a second connecting segment 11114 and a third connecting segment 11115, the second connecting segment 11114, the first connecting segment 11113 and the third connecting segment 11115 are arranged along a third direction X, the first connecting segment 11113 connects the second connecting segment 11114 and the third connecting segment 11115, and the thickness of the first connecting segment 11113 is greater than the thickness of the second connecting segment 11114 and the thickness of the third connecting segment 11115.

[0207] The first connecting segment 11113 is a segment that passes through the middle section of the first wall 111 in the first region 1111, and the second connecting segment 11114 and the third connecting segment 11115 are two segments located at two ends of the first region 1111 along the third direction X. The second connecting segment 11114 and the first connecting segment 11113 may be directly connected or indirectly connected, and the third connecting segment 11115 and the first connecting segment 11113 may be directly connected or indirectly connected.

[0208] The first connecting segment 11113 may have a uniform thickness structure or a non-uniform thickness structure, the second connecting segment 11114 may have a uniform thickness structure or a non-uniform thickness structure, and the third connecting segment 11115 may have a uniform thickness structure or a non-uniform thickness structure. If at least one of the first connecting segment 11113 and the second connecting segment 11114 has a non-uniform thickness structure, the maximum thickness of the second connecting segment 11114 may be less than or equal to the minimum thickness of the first connecting segment 11113, thereby ensuring that the thickness of the first connecting segment 11113 is greater than the thickness of the second connecting segment 11114. If at least one of the third connecting segment 11115 and the first connecting segment 11113 has a non-uniform thickness structure, the maximum thickness of the third connecting segment 11115 may be less than or equal to the minimum thickness of the first connecting segment 11113, thereby ensuring that the thickness of the first connecting segment 11113 is greater than the thickness of the third connecting segment 11115.

[0209] The size of the second connecting segment 11114 along the third direction X may or may not be equal to the size of the third connecting segment 11115 along the third direction X. If the size of the second connecting segment 11114 along the third direction X is equal to the size of the third connecting segment 11115 along the third direction X, the second connecting segment 11114 and the third connecting segment 11115 may be installed symmetrically with respect to the middle section of the first wall 111.

[0210] To make it clear, in an embodiment in which the first region 1111 includes a first portion 11111 and a second portion 11112, at least one of the first connecting segment 11113, the second connecting segment 11114, and the third connecting segment 11115 may include the first portion 11111 and the second portion 11112 arranged along the first direction Z.

[0211] The second connecting segment 11114 may partially protrude from the first inner surface 11121 (not shown in Figures 15 and 16) and / or the first outer surface 11122 (not shown in Figures 15 and 16), the first connecting segment 11113 may partially protrude from the first inner surface 11121 and / or the first outer surface 11122, and the third connecting segment 11115 may partially protrude from the first inner surface 11121 and / or the first outer surface 11122.

[0212] For example, in the embodiment shown in Figure 16, the second connection segment 11114 and the third connection segment 11115 are both directly connected to the first connection segment 11113, the thickness of the second connection segment 11114 gradually decreases along the direction in which the third connection segment 11115 moves toward the second connection segment 11114, and the thickness of the third connection segment 11115 gradually decreases along the direction in which the second connection segment 11114 moves toward the third connection segment 11115. Parts of the second connection segment 11114, part of the first connection segment 11113, and part of the third connection segment 11115 all protrude from the first inner surface 11121 of the second region 1112. The inner surface of the second connecting segment 11114 is connected to the inner surface of the first connecting segment 11113 and the first inner surface 11121, and the inner surface of the third connecting segment 11115 is connected to the inner surface of the first connecting segment 11113 and the first inner surface 11121, and the outer surfaces of the second connecting segment 11114, the first connecting segment 11113 and the third connecting segment 11115 are on the same plane.

[0213] When the first wall 111 is subjected to the expansion force of the electrode assembly 2, the amount of deformation of the first wall 111 gradually decreases from the middle to both ends along the third direction X. By dividing the first region 1111 into a multi-stage structure and setting the thickness of the first connecting segment 11113 located in the intermediate region to be greater than that of the first connecting segment 11113, and setting the thickness of the second connecting segment 11114 and the third connecting segment 11115 located at both ends of the first connecting segment 11113 to be smaller, the first region 1111 is intentionally designed based on the difference in the amount of deformation of different regions of the first wall 111 along the third direction X, thereby intentionally improving the strength of different regions of the first wall 111 along the third direction X, providing sufficient strength to the region located near the first connection part 51 of the first wall 111, while simultaneously reducing the amount of material used in the first region 1111 and lowering production costs.

[0214] In some embodiments, referring to Figures 17 and 18, Figure 17 is a perspective view of Case 11 according to yet another embodiment of the present application, and Figure 18 is a plan view of Case 11 shown in Figure 17. The first region 1111 further includes a first transition segment 11116, and the first connecting segment 11113, the first transition segment 11116 and the second connecting segment 11114 are arranged along a third direction X, the first transition segment 11116 connects the second connecting segment 11114 and the first connecting segment 11113, the thickness of the first transition segment 11116 tends to increase along the direction in which the second connecting segment 11114 is toward the first connecting segment 11113, and / Alternatively, the first region 1111 further includes a second transition segment 11117, and the first connection segment 11113, the second transition segment 11117, and the third connection segment 11115 are arranged along a third direction X, with the second transition segment 11117 connecting the third connection segment 11115 and the first connection segment 11113, and the thickness of the second transition segment 11117 tends to increase along the direction in which the third connection segment 11115 is toward the first connection segment 11113.

[0215] The first transition segment 11116 has a non-uniform thickness structure. For example, the thickness of the first transition segment 11116 gradually increases along the direction in which the second connecting segment 11114 moves toward the first connecting segment 11113. The second transition segment 11117 has a non-uniform thickness structure. For example, the thickness of the second transition segment 11117 gradually increases along the direction in which the third connecting segment 11115 moves toward the first connecting segment 11113.

[0216] When a first transition segment 11116 is installed between a second connection segment 11114 and a first connection segment 11113, and a second transition segment 11117 is installed between a third connection segment 11115 and a first connection segment 11113, the size of the first transition segment 11116 along the third direction X and the size of the second transition segment 11117 along the third direction X may be equal or not equal. If the size of the first transition segment 11116 along the third direction X is equal to the size of the second transition segment 11117 along the third direction X, the first transition segment 11116 and the second transition segment 11117 may be installed symmetrically with respect to the middle section of the first wall 111.

[0217] To make it clear, if a first transition segment 11116 is placed between a second connection segment 11114 and a first connection segment 11113, the first transition segment 11116 may partially protrude from the first inner surface 11121 (not shown in Figures 17 and 18) and / or the first outer surface 11122 (not shown in Figures 17 and 18) of the second region 1112, and if a second transition segment 11117 is placed between a third connection segment 11115 and a first connection segment 11113, the second transition segment 11117 may partially protrude from the first inner surface 11121 and / or the first outer surface 11122 of the second region 1112.

[0218] For example, in the embodiment shown in Figure 18, the second connection segment 11114 and the first connection segment 11113 are indirectly connected via the first transition segment 11116, and the third connection segment 11115 and the first connection segment 11113 are indirectly connected via the second transition segment 11117. The thickness of the first transition segment 11116 gradually increases along the direction from the second connection segment 11114 toward the first connection segment 11113, and the thickness of the second transition segment 11117 gradually increases along the direction from the third connection segment 11115 toward the first connection segment 11113. Parts of the second connection segment 11114, part of the first connection segment 11113, part of the third connection segment 11115, part of the first transition segment 11116, and part of the second transition segment 11117 all protrude from the first inner surface 11121. The inner surface of the first transition segment 11116 is connected to the inner surface of the first connecting segment 11113 and the inner surface of the second connecting segment 11114, the inner surface of the second transition segment 11117 is connected to the inner surface of the first connecting segment 11113 and the inner surface of the third connecting segment 11115, and the outer surfaces of the second connecting segment 11114, the first connecting segment 11113, the third connecting segment 11115, the first transition segment 11116, and the second transition segment 11117 are all on the same plane.

[0219] In this embodiment, if the second connecting segment 11114 and the first connecting segment 11113 are connected via the first transition segment 11116, and the thickness of the first transition segment 11116 tends to increase in the direction in which the second connecting segment 11114 moves toward the first connecting segment 11113, then the first transition segment 11116 can realize a transition between the second connecting segment 11114 and the first connecting segment 11113, thereby reducing stress concentration. If the third connecting segment 11115 and the first connecting segment 11113 are connected via the second transition segment 11117, and the thickness of the second transition segment 11117 tends to increase in the direction in which the third connecting segment 11115 moves toward the first connecting segment 11113, then the second transition segment 11117 can realize a transition between the third connecting segment 11115 and the first connecting segment 11113, thereby reducing stress.

[0220] In some embodiments, referring again to Figures 14, 16, and 18, the size of the first connecting segment 11113 along the third direction X is L1, and the size of the first wall 111 along the third direction X is L, where 0.2 ≤ L1 / L ≤ 0.6.

[0221] The size of the first connecting segment 11113 along the third direction X is the length of the first connecting segment 11113, the size of the first wall 111 along the third direction X is the length of the first wall 111, the size of the first wall 111 along the second direction Y is the thickness of the first wall 111, and the size of the first wall 111 along the first direction Z is the width of the first wall 111.

[0222] L1 / L can take the value of any one of the following points, or a range value between any two of them, such as 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.52, 0.55, 0.58, 0.6, etc.

[0223] If L1 / L ≥ 0.2, the ratio of the size of the first connecting segment 11113 along the third direction X in the first wall 111 is increased, thereby increasing the area in which the intermediate region of the first wall 111 along the third direction X is reinforced, and improving the strength of the intermediate region of the first wall 111 along the third direction X. If L1 / L ≤ 0.6, the ratio of the size of the first connecting segment 11113 along the third direction X in the first wall 111 is decreased, reducing the amount of material used for the first connecting segment 11113 and lowering production costs. Therefore, the ratio of the size of the first connecting segment 11113 along the third direction X to the size of the first wall 111 along the third direction X is set to 0.2 to 0.6, so that the first connecting segment 11113 has sufficient reinforcing capacity while reducing the amount of material used for the first connecting segment 11113, thus achieving both the reinforcing capacity requirement and the economic requirement for the first connecting segment 11113.

[0224] In some embodiments, referring again to Figures 14, 16 and 18, the first connecting segment 11113 has a first end 11113a and a second end 11113b facing each other along the third direction X, the first wall 111 has a third end 1113 and a fourth end 1114 facing each other along the third direction X, the first end 11113a is close to the third end 1113, the second end 11113b is close to the fourth end 1114, the size of the first wall 111 along the third direction X is L, the minimum distance along the third direction X between the first end 11113a and the third end 1113 is L2, the minimum distance along the third direction X between the second end 11113b and the fourth end 1114 is L3, L2 / L ≤ 0.3 and / or L3 / L ≤ 0.3.

[0225] To make it clear, along the third direction X, the first end 11113a is closer to the third end 1113 than the second end 11113b, and the second end 11113b is closer to the fourth end 1114 than the first end 11113a.

[0226] L2 = L3 is also acceptable, and L2 > L3 or L2 <L3であってもよい。

[0227] L2 / L can take the value of any one of the following points, or a range value between any two of them: 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, etc.

[0228] L3 / L can take the value of any one of the following points, or a range value between any two of them: 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, etc.

[0229] If L2 / L ≤ 0.3, the ratio of the minimum distance along the third direction X between the first end 11113a and the third end 1113 to the size of the first wall 111 along the third direction X is reduced, thereby reinforcing the strength of more areas of the first wall 111 along the third direction X and further reducing the risk of fatigue and cracking of the area of ​​the first wall 111 located near the first connection 51. If L3 / L ≤ 0.3, the ratio of the minimum distance along the third direction X between the second end 11113b and the fourth end 1114 to the size of the first wall 111 along the third direction X is reduced, thereby reinforcing the strength of more areas of the first wall 111 along the third direction X and further reducing the risk of fatigue and cracking of the area of ​​the first wall 111 located near the first connection 51.

[0230] In some embodiments, 100mm ≤ L ≤ 450mm.

[0231] L can take the value of any one point or the range value between any two of 100 mm, 120 mm, 150 mm, 180 mm, 200 mm, 220 mm, 250 mm, 260 mm, 280 mm, 300 mm, 310 mm, 320 mm, 350 mm, 390 mm, 400 mm, 410 mm, 420 mm, 430 mm, 440 mm, 450 mm, etc.

[0232] In some embodiments, continuing to refer to FIGS. 13-18, the case 11 includes a corner wall 113. At both ends along the third direction X of the first wall 111, corner walls 113 are connected. At least one end along the third direction X of the first region 1111 does not contact the corner wall 113, or both ends along the third direction X of the first region 1111 extend to two corner walls 113 respectively.

[0233] Along the third direction X, the first region 1111 has opposite ends. One end of the first region 1111 may extend to one corner wall 113, and the other end may not extend to another corner wall 113. Both ends of the first region 1111 may not extend to the corner walls 113, thereby realizing that at least one end along the third direction X of the first region 1111 does not contact the corner wall 113.

[0234] [[ID=eleven]] As an example, in the embodiment shown in FIGS. 13-18, along the third direction X, one end of the first region 1111 does not contact the corner wall 113 at one end of the first wall 111, and the other end of the first region 1111 does not contact the corner wall 113 at the other end of the first wall 111.

[0235] If at least one end of the first region 1111 along the third direction X does not come into contact with the corner wall 113, the amount of material used in the first region 1111 can be reduced, thereby lowering production costs. If both ends of the first region 1111 along the third direction X extend to the two corner walls 113, the length of the first region 1111 can be increased, improving its reinforcing capacity, reinforcing a larger area of ​​the first wall 111 along the third direction X, and further reducing the risk of fatigue and cracking in the area of ​​the first wall 111 located near the first connection 51.

[0236] In some embodiments, referring to Figures 19-21, Figure 19 is a partial view of a battery cell 10 according to some embodiments of the present application (showing the positive electrode plate 22, negative electrode plate 23 and separator member 24 of the electrode assembly 2), Figure 20 is a positional relationship diagram of the positive electrode plate 22, negative electrode plate 23 and separator member 24 according to some embodiments of the present application, and Figure 21 is a positional relationship diagram of the positive electrode plate 22, negative electrode plate 23 and separator member 24 according to some other embodiments of the present application. The electrode assembly 2 further includes a separator member 24, which is positioned between the positive electrode plate 22 and the negative electrode plate 23. The positive electrode plate 22 includes a positive electrode body region 221 and a positive electrode tab 21a protruding from the positive electrode body region 221, the positive electrode body region 221 having a positive electrode active material layer 223. The negative electrode plate 23 includes a negative electrode body region 231 and a negative electrode tab 21b protruding from the negative electrode body region 231, the negative electrode body region 231 having a negative electrode active material layer 233. Along the first direction Z, the positive electrode body region 221 has a fifth end 2211 facing the end cap 12, the negative electrode body region 231 has a sixth end 2311 facing the end cap 12, and the separator member 24 has a seventh end 241 facing the end cap 12, the seventh end 241 being closer to the end cap 12 than the fifth end 2211 and the sixth end 2311.

[0237] In this embodiment, the electrode assembly 2 may have a wound structure or a laminated structure.

[0238] The positive electrode plate 22 may include a positive electrode current collector 222 and a positive electrode active material layer 223, wherein the positive electrode active material layer 223 is provided on one or two surfaces of the positive electrode current collector 222 in its thickness direction. In the embodiment shown in Figure 20, the positive electrode plate 22 further includes an insulating layer 224, the insulating layer 224 is provided on two opposing surfaces of the positive electrode current collector 222 in its thickness direction, the insulating layer 224 and the positive electrode active material layer 223 are arranged along a first direction Z, the insulating layer 224 is provided at the end of the positive electrode active material layer 223, the portion of the positive electrode plate 22 corresponding to the entire positive electrode active material layer 223 and insulating layer 224 is the positive electrode body region 221, one end of the insulating layer 224 adjacent to the end cap 12 forms the fifth end 2211 of the positive electrode body region 221, and the portion of the positive electrode current collector 222 that extends beyond the insulating layer 224 forms the positive electrode tab 21a. In the embodiment shown in Figure 21, no insulating layer 224 is installed on the positive electrode plate 22. The portion of the positive electrode plate 22 corresponding to the positive electrode active material layer 223 is the positive electrode body region 221. One end of the positive electrode active material layer 223 adjacent to the end cap 12 forms the fifth end 2211 of the positive electrode body region 221, and the portion of the positive electrode current collector 222 that extends beyond the positive electrode active material layer 223 forms the positive electrode tab 21a.

[0239] The negative electrode plate 23 may include a negative electrode current collector 232 and a negative electrode active material layer 233, wherein the negative electrode active material layer 233 is provided on one or two surfaces in the thickness direction of the negative electrode current collector 232. The portion of the negative electrode plate 23 corresponding to the negative electrode active material layer 233 is the negative electrode body region 231, and one end of the negative electrode active material layer 233 adjacent to the end cap 12 forms the sixth end 2311 of the negative electrode body region 231, and the portion of the negative electrode current collector 232 that extends beyond the negative electrode active material layer 233 forms the negative electrode tab 21b.

[0240] The fifth end 2211 may be aligned with the sixth end 2311, and as shown in Figure 20, the fifth end 2211 may be closer to the end cap 12 (shown in Figure 19) than the sixth end 2311, and as shown in Figure 21, the sixth end 2311 may be closer to the end cap 12 (shown in Figure 19) than the fifth end 2211.

[0241] In this embodiment, the seventh end 241 of the separator member 24 is closer to the end cap 12 than the fifth end 2211 of the positive electrode body region 221 and the sixth end 2311 of the negative electrode body region 231, so that the separator member 24 has portions that extend beyond the fifth end 2211 and the sixth end 2311, thereby enhancing the insulating effect between the positive electrode plate 22 and the negative electrode plate 23 of the separator member 24 and reducing the risk of the positive electrode plate 22 and the negative electrode plate 23 coming into contact.

[0242] In some embodiments, referring again to Figures 19-21, the separator member 24 includes an overhang region 242 that extends beyond the fifth end 2211 and the sixth end 2311 along the first direction Z, and in a projection plane perpendicular to the second direction Y, the orthographic projection of the overhang region 242 partially overlaps with the orthographic projection of the first region 1111.

[0243] The protruding region 242 is the portion of the separator member 24 that extends beyond both the fifth end 2211 of the positive electrode body region 221 and the sixth end 2311 of the negative electrode body region 231. To make it clear, as shown in Figure 20, in an embodiment where the fifth end 2211 is closer to the end cap 12 than the sixth end 2311, the portion of the separator member 24 that extends beyond the fifth end 2211 is the protruding region 242, and as shown in Figure 21, in an embodiment where the sixth end 2311 is closer to the end cap 12 than the fifth end 2211, the portion of the separator member 24 that extends beyond the sixth end 2311 is the protruding region 242.

[0244] For example, in Figures 19-21, the portions of the positive electrode plate 22, negative electrode plate 23, and separator member 24 in the electrode assembly 2 located in a flat region 25 (not shown in Figures 19-21) are stacked and installed along the second direction Y.

[0245] In this embodiment, in the projection plane perpendicular to the second direction Y, the orthographic projection of the overhang region 242 partially overlaps with the orthographic projection of the first region 1111. Such a structure can increase the size of the first region 1111 along the first direction Z, improving the reinforcing capacity of the first region 1111, reinforcing a larger area of ​​the first wall 111 along the first direction Z, and further reducing the risk of fatigue and cracking in the area of ​​the first wall 111 located near the first connection 51.

[0246] In some embodiments, referring again to Figures 19-21, the second region 1112 has a first inner surface 11121 facing the internal space of the case 11, and the first region 1111 includes a first projection 11118 protruding from the first inner surface 11121. In a projection plane perpendicular to the second direction Y, the orthographic projection of the positive electrode body region 221 does not overlap with the orthographic projection of the first projection 11118, and / or, in a projection plane perpendicular to the second direction Y, the orthographic projection of the negative electrode body region 231 does not overlap with the orthographic projection of the first projection 11118.

[0247] The first projection 11118 is the portion of the first region 1111 that protrudes from the first inner surface 11121 of the second region 1112, and the first projection 11118 may have a uniform thickness structure or a non-uniform thickness structure. Along the first direction Z, the first projection 11118 may extend to the first connecting portion 51, thereby directly connecting the first projection 11118 to the first connecting portion 51.

[0248] To make it clear, in an embodiment in which the first region 1111 includes a first portion 11111 and a second portion 11112 arranged along a first direction Z, a portion of the first projection 11118 may be located in the first portion 11111 and the other portion in the second portion 11112. In an embodiment in which the first region 1111 includes a first connecting segment 11113, a second connecting segment 11114 and a third connecting segment 11115 arranged along a third direction X, a portion of the first projection 11118 may be located in the first connecting segment 11113, the other portion of the first projection 11118 may be located in the second connecting segment 11114, and yet another portion of the first projection 11118 may be located in the third connecting segment 11115.

[0249] For example, in the embodiment shown in Figures 19-21, the orthographic projections of the positive electrode body region 221 and the first protrusion 11118 do not overlap in the projection plane perpendicular to the second direction Y, and the orthographic projection of the negative electrode body region 231 and the first protrusion 11118 do not overlap.

[0250] If the orthographic projection of the positive electrode body region 221 and the orthographic projection of the first protrusion 11118 do not overlap in a projection plane perpendicular to the second direction Y, then case 11 can provide a larger expansion space for the electrode assembly 2, reducing the risk of the electrode assembly 2 expanding and directly applying an expansion force to the first protrusion 11118, reducing the amount of deformation of the first wall 111, and further reducing the risk of fatigue and cracking of the region of the first wall 111 located near the first connection 51. If the orthographic projection of the negative electrode body region 231 and the orthographic projection of the first protrusion 11118 do not overlap in a projection plane perpendicular to the second direction Y, then case 11 can provide a larger expansion space for the electrode assembly 2, reducing the risk of the electrode assembly 2 expanding and directly applying an expansion force to the first protrusion 11118, reducing the amount of deformation of the first wall 111, and further reducing the risk of fatigue and cracking of the region of the first wall 111 located near the first connection 51.

[0251] In some embodiments, continuing with reference to Figures 19-21, the negative electrode plate 23 includes a negative electrode current collector 232 and a negative electrode active material layer 233 installed on at least one side of the negative electrode current collector 232, the negative electrode active material layer 233 includes a negative electrode active material.

[0252] The negative electrode active material layer 233 may be installed on only one side of the negative electrode current collector 232, that is, on only one surface of the negative electrode current collector 232 along the thickness direction, or the negative electrode active material layer 233 may be installed on both opposing sides of the negative electrode current collector 232, that is, on both of the two opposing surfaces of the negative electrode current collector 232 along the thickness direction.

[0253] The negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate.

[0254] In some embodiments, the negative electrode active material layer 233 includes a negative electrode body portion 2331 and a negative electrode thin-walled portion 2332, which are arranged along a first direction Z, and the negative electrode thin-walled portion 2332 is located at one end of the negative electrode body portion 2331 adjacent to the end cap 12 along the first direction Z.

[0255] The thickness of the negative electrode body portion 2331 is greater than the thickness of the negative electrode thin-walled portion 2332. The negative electrode thin-walled portion 2332 may be installed only at one end of the negative electrode body portion 2331 that is close to the end cap 12 along the first direction Z, or the negative electrode thin-walled portion 2332 may be present at both ends of the negative electrode body portion 2331 along the first direction Z. The negative electrode body portion 2331 may have a uniform thickness structure or a non-uniform thickness structure, and the negative electrode thin-walled portion 2332 may have a uniform thickness structure or a non-uniform thickness structure. If at least one of the negative electrode body portion 2331 and the negative electrode thin-walled portion 2332 has a non-uniform thickness structure, the maximum thickness of the negative electrode thin-walled portion 2332 may be less than or equal to the minimum thickness of the negative electrode body portion 2331, thereby achieving that the thickness of the negative electrode body portion 2331 is greater than the thickness of the negative electrode thin-walled portion 2332.

[0256] As an example, the negative electrode main body portion 2331 has an equal-thickness structure, and the thickness of the negative electrode thin portion 2332 shows a decreasing tendency along the direction in which the negative electrode main body portion 2331 faces the negative electrode thin portion 2332.

[0257] In this embodiment, the negative electrode thin portion 2332 is installed at one end of the negative electrode main body portion 2331 close to the end cap 12. The electrode assembly 2 has a larger expansion gap in the region corresponding to the negative electrode thin portion 2332. The region of the electrode assembly 2 corresponding to the negative electrode thin portion 2332 has a smaller force applied to the first wall 111 after expansion, and can reduce the risk that the region located near the first connection portion 51 of the first wall 111 is fatigued and cracked.

[0258] In some embodiments, in the projection plane perpendicular to the second direction Y, the orthographic projection of the negative electrode thin portion 2332 located at one end of the negative electrode main body portion 2331 close to the end cap 12 and the orthographic projection of the first region 1111 are arranged at intervals along the first direction Z.

[0259] As can be understood, in the projection plane perpendicular to the second direction Y, the orthographic projection of the negative electrode thin portion 2332 located at one end of the negative electrode main body portion 2331 close to the end cap 12 does not overlap with the orthographic projection of the first region 1111.

[0260] In this embodiment, in the projection plane perpendicular to the second direction Y, the orthographic projection of the negative electrode thin portion 2332 located at one end of the negative electrode main body portion 2331 close to the end cap 12 and the orthographic projection of the first region 1111 are arranged at intervals along the first direction Z, reducing the influence of the negative electrode thin portion 2332 on the first region 1111, reducing the risk that the electrode assembly 2 expands and directly applies an expansion force to the first region 1111, and further reducing the risk that the region located near the first connection portion 51 of the first wall 111 is fatigued and cracked.

[0261] In some embodiments, the spacing size along the first direction Z between the orthographic projection of the negative electrode thin-walled portion 2332 located at one end of the negative electrode body portion 2331 adjacent to the end cap 12 and the orthographic projection of the first region 1111 in a projection plane perpendicular to the second direction Y is 1 mm or more.

[0262] In a projection plane perpendicular to the second direction Y, the spacing size along the first direction Z between the orthographic projection of the negative electrode thin-walled portion 2332 located at one end of the negative electrode body portion 2331 adjacent to the end cap 12 and the orthographic projection of the first region 1111 is W1, where W1 ≥ 1 mm. This spacing size is the minimum distance along the first direction Z of the orthographic projections of both the negative electrode thin-walled portion 2332 and the first region 1111 in a projection plane perpendicular to the second direction Y. W1 can be the value of any one point or a range value between any two of the following: 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, etc.

[0263] In this embodiment, by setting W1 ≥ 1 mm, the distance along the first direction Z between the orthographic projection of the negative electrode thin-walled portion 2332 and the orthographic projection of the first region 1111 in the projection plane perpendicular to the second direction Y becomes greater, further reducing the influence of the negative electrode thin-walled portion 2332 on the first region 1111.

[0264] In some embodiments, the single-sided coating weight of the negative electrode active material layer 233 is 90 mg / 1540 mm². 2 ~170mg / 1540mg 2 That is the case.

[0265] The coating weight on one side of the negative electrode active material layer 233 is 90 mg / 1540 mm². 2 , 100mg / 1540mg 2 , 110mg / 1540mg 2 , 120mg / 1540mg 2 , 130mg / 1540mg 2 , 140mg / 1540mg 2 , 150mg / 1540mg 2, 160mg / 1540mg 2 , 170mg / 1540mg 2 It can take the value of any one of these points or a range value between any two of them.

[0266] When measuring the single-sided coating weight of the negative electrode active material layer 233, a single-sided coated negative electrode plate 23 (if it is a double-sided coated negative electrode plate 23, the negative electrode active material layer 233 on one side can be wiped off first) can be taken, punched out onto a wafer with area S1, and its weight can be weighed and recorded as M1. Next, the negative electrode active material layer 233 on the weighed negative electrode plate 23 is wiped off, and the weight of the negative electrode current collector 232 is weighed and recorded as M2. The single-sided coating weight of the negative electrode active material layer 233 is (M1 - M2) / S1.

[0267] The single-sided coating weight of the negative electrode active material layer 233 is related to the expansion of the negative electrode active material layer 233, and the single-sided coating weight of the negative electrode active material layer 233 is 90 mg / 1540 mm 2 ~170mg / 1540mg 2 By setting it to such a configuration, it is possible to reconcile to some extent the high energy density requirement of the battery cell 10 with the low expansion requirement of the negative electrode plate 23, thereby reducing the impact of the expansion of the negative electrode plate 23 on the first wall 111 and reducing the risk of fatigue and cracking in the region of the first wall 111 located near the first connection portion 51.

[0268] In some embodiments, the single-sided coating weight of the negative electrode active material layer 233 is 110 mg / 1540 mm². 2 ~150mg / 1540mg 2 That is the case.

[0269] In this embodiment, the single-sided coating weight of the negative electrode active material layer 233 is 110 mg / 1540 mm². 2 , 115mg / 1540mg 2 , 120mg / 1540mg 2 , 125mg / 1540mg 2 , 130mg / 1540mg 2 , 135mg / 1540mg 2 , 140mg / 1540mg 2, 145mg / 1540mg 2 , 150mg / 1540mg 2 It can take the value of any one of these points or a range value between any two of them.

[0270] In this embodiment, the single-sided coating weight of the negative electrode active material layer 233 is 110 mg / 1540 mm². 2 ~150mg / 1540mg 2 This further improves the energy density of the battery cell 10 and further reduces the expansion of the negative electrode plate 23.

[0271] In some embodiments, the porosity of the negative electrode plate 23 is 27% to 40%.

[0272] The porosity of the negative electrode plate 23 can be any one of the values ​​of 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, etc., or a range value between any two of these values.

[0273] The porosity of the negative electrode plate 23 may be the percentage of the pore volume within the negative electrode plate 23 relative to the total volume of the negative electrode plate 23. For example, when the battery cell 10 is in a 0% charged state, the porosity of the negative electrode plate 23 is obtained by taking the negative electrode plates 23 coated on both sides and measuring them using a true density meter AccuPyc II 1340 in accordance with the Chinese national standard GB / T 24586-2009.

[0274] In this embodiment, the porosity of the negative electrode plate 23 is 27% to 40%, and in this way the negative electrode plate 23 provides space for impurities generated by the side reaction, mitigating the expansion of the negative electrode plate 23 and reducing the impact of the expansion of the negative electrode plate 23 on the first wall 111.

[0275] In some embodiments, the negative electrode active material includes a silicon-based material, and the mass content of silicon elements in the silicon-based material in the negative electrode active material is 0.3% to 10%, and selectively 1% to 6%.

[0276] The mass content of silicon elements in the negative electrode active material of silicon-based materials can be any one of the following values: 0.3%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or a range between any two of these values.

[0277] In some embodiments, the silicon-based material includes at least one of a silicon-oxygen compound and a silicon-carbon composite.

[0278] In some embodiments, referring to Figures 19-21, the positive electrode plate 22 includes a positive electrode current collector 222 and a positive electrode active material layer 223 installed on at least one side of the positive electrode current collector 222, the positive electrode active material layer 223 includes a positive electrode active material.

[0279] The positive electrode active material layer 223 may be installed on only one side of the positive electrode current collector 222, that is, on only one surface along the thickness direction of the positive electrode current collector 222, or the positive electrode active material layer 223 may be installed on both opposing sides of the positive electrode current collector 222, that is, on both of the two opposing surfaces along the thickness direction of the positive electrode current collector 222.

[0280] The positive electrode active material may contain at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each.

[0281] In some embodiments, the positive electrode active material layer 223 includes a positive electrode body portion 2231 and a positive electrode thin-walled portion 2232, which are arranged along a first direction Z, and the positive electrode thin-walled portion 2232 is positioned along the first direction Z at one end of the positive electrode body portion 2231 adjacent to the end cap 12.

[0282] The thickness of the positive electrode body portion 2231 is greater than the thickness of the positive electrode thin-walled portion 2232. The positive electrode thin-walled portion 2232 may be installed only at one end of the positive electrode body portion 2231 that is close to the end cap 12 along the first direction Z, or the positive electrode thin-walled portion 2232 may be present at both ends of the positive electrode body portion 2231 along the first direction Z. The positive electrode body portion 2231 may have a uniform thickness structure or a non-uniform thickness structure, and the positive electrode thin-walled portion 2232 may have a uniform thickness structure or a non-uniform thickness structure. If at least one of the positive electrode body portion 2231 and the positive electrode thin-walled portion 2232 has a non-uniform thickness structure, the maximum thickness of the positive electrode thin-walled portion 2232 may be less than or equal to the minimum thickness of the positive electrode body portion 2231, thereby achieving that the thickness of the positive electrode body portion 2231 is greater than the thickness of the positive electrode thin-walled portion 2232.

[0283] For example, the positive electrode body portion 2231 has a uniform thickness structure, and the thickness of the positive electrode thin-walled portion 2232 tends to decrease along the direction in which the positive electrode body portion 2231 moves toward the positive electrode thin-walled portion 2232.

[0284] In this embodiment, a positive electrode thin-walled portion 2232 is provided at one end of the positive electrode body portion 2231 adjacent to the end cap 12, and the electrode assembly 2 has a larger expansion gap in the region corresponding to the positive electrode thin-walled portion 2232. As a result, the force applied to the first wall 111 in the region of the electrode assembly 2 corresponding to the positive electrode thin-walled portion 2232 is smaller after expansion, and the risk of fatigue and cracking in the region located near the first connection portion 51 of the first wall 111 can be reduced.

[0285] In some embodiments, the orthographic projection of the positive electrode thin-walled portion 2232 located at one end of the positive electrode body portion 2231 adjacent to the end cap 12, and the orthographic projection of the first region 1111 are spaced apart along the first direction Z in a projection plane perpendicular to the second direction Y.

[0286] To make it clear, in a projection plane perpendicular to the second direction Y, the orthographic projection of the positive electrode thin-walled portion 2232 located at one end of the positive electrode body portion 2231 adjacent to the end cap 12 does not overlap with the orthographic projection of the first region 1111.

[0287] In a projection plane perpendicular to the second direction Y, the orthographic projection of the positive electrode thin-walled portion 2232 located at one end of the positive electrode body portion 2231 adjacent to the end cap 12 and the orthographic projection of the first region 1111 are spaced apart along the first direction Z, thereby reducing the influence of the positive electrode thin-walled portion 2232 on the first region 1111, reducing the risk of the electrode assembly 2 expanding and directly applying an expansion force to the first region 1111, and further reducing the risk of fatigue and cracking of the region located near the first connection portion 51 of the first wall 111.

[0288] In some embodiments, the spacing size along the first direction Z between the orthographic projection of the positive electrode thin-walled portion 2232 located at one end of the positive electrode body portion 2231 adjacent to the end cap 12 and the orthographic projection of the first region 1111 in a projection plane perpendicular to the second direction Y is 1 mm or more.

[0289] In a projection plane perpendicular to the second direction Y, the spacing size along the first direction Z between the orthographic projection of the positive electrode thin-walled portion 2232 located at one end of the positive electrode body portion 2231 adjacent to the end cap 12 and the orthographic projection of the first region 1111 is W2, where W2 ≥ 1 mm. This spacing size is the minimum distance along the first direction Z of the orthographic projections of both the positive electrode thin-walled portion 2232 and the first region 1111 in the projection plane perpendicular to the second direction Y. Here, W1 = W2, W1 ≤ W2, and W1 ≥ W2. W2 can take the value of any one point or a range value between any two of the following: 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, etc.

[0290] In this embodiment, W2 ≥ 1 mm, which increases the distance along the first direction Z between the orthographic projection of the positive electrode thin-walled portion 2232 and the orthographic projection of the first region 1111 in the projection plane perpendicular to the second direction Y, further reducing the influence of the positive electrode thin-walled portion 2232 on the first region 1111.

[0291] In some embodiments, the single-sided coating weight of the positive electrode active material layer 223 is 200 mg / 1540 mm². 2 ~370mg / 1540mg 2 That is the case.

[0292] The coating weight on one side of the positive electrode active material layer 223 is 200 mg / 1540 mm². 2 210mg / 1540mg 2 , 220mg / 1540mg 2 230mg / 1540mg 2 , 240mg / 1540mg 2 250mg / 1540mg 2 , 260mg / 1540mg 2 , 270mg / 1540mg 2 280mg / 1540mg 2 290mg / 1540mg 2 300mg / 1540mg 2 310mg / 1540mg 2 320mg / 1540mg 2 330mg / 1540mg 2 340mg / 1540mg 2 350mg / 1540mg 2 360mg / 1540mg 2 370mg / 1540mg 2 It can take the value of any one of these points or a range value between any two of them.

[0293] When measuring the single-sided coating weight of the positive electrode active material layer 223, a single-sided coated positive electrode plate 22 (if it is a double-sided coated positive electrode plate 22, the positive electrode active material layer 223 on one side can be wiped off first) is taken, punched out onto a wafer with an area of ​​S2, and its weight is weighed and recorded as M3. Next, the positive electrode active material layer 223 is wiped off the positive electrode plate 22 after the above weighing, and the weight of the positive electrode current collector 222 is weighed and recorded as M4. The single-sided coating weight of the positive electrode active material layer 223 is (M3 - M4) / S2.

[0294] The single-sided coating weight of the positive electrode active material layer 223 is related to the expansion of the positive electrode active material layer 223. By setting the single-sided coating weight of the positive electrode active material layer 223 to 200 mg / 1540 mm 2 ~370 mg / 1540 mm 2 it is possible to balance the high energy density requirement of the battery cell 10 and the low expansion requirement of the positive electrode plate 22 to a certain extent. Thereby, the influence of the expansion of the positive electrode plate 22 on the first wall 111 can be reduced, and the risk that the region located near the first connection portion 51 of the first wall 111 is fatigued and cracked can be reduced.

[0295] In some embodiments, the single-sided coating weight of the positive electrode active material layer 223 is 240 mg / 1540 mm 2 ~330 mg / 1540 mm 2 is.

[0296] The single-sided coating weight of the positive electrode active material layer 223 is 240 mg / 1540 mm 2 , 245 mg / 1540 mm 2 , 250 mg / 1540 mm 2 , 255 mg / 1540 mm 2 , 260 mg / 1540 mm 2 , 265 mg / 1540 mm 2 , 270 mg / 1540 mm 2 , 275 mg / 1540 mm 2 , 280 mg / 1540 mm 2 [[ID=·34]], 285 mg / 1540 mm 2 , 290 mg / 1540 mm 2 , 295 mg / 1540 mm 2 , 300 mg / 1540 mm 2 , 305 mg / 1540 mm 2 , 310 mg / 1540 mm 2 , 315 mg / 1540 mm 2 , 320 mg / ·1540 mm 2 , 325 mg / 1540 mm 2 , 330 mg / 1540 mm 2 It can take the value of any one point or the range value between any two of the above.

[0297] In this embodiment, the single-sided coating weight of the positive electrode active material layer 223 is 240 mg / 1540 mm². 2 ~330mg / 1540mg 2 This further improves the energy density of the battery cell 10 and further reduces the expansion of the positive electrode plate 22.

[0298] In some embodiments, the positive electrode active material is a lithium-containing phosphate.

[0299] In some embodiments, referring to Figures 22-24, Figure 22 is a partial view of a battery cell 10 according to some embodiments of the present application (showing the first wall 111), Figure 23 is a partial view of the first wall 111 shown in Figure 22, and Figure 24 is a perspective view of the case 11 shown in Figure 22. The material of the case 11 includes steel. The maximum thickness of the second region 1112 is D1, and the size of the case 11 along the second direction Y is D, where 0.001 ≤ D1 / D ≤ 0.012.

[0300] The thickness at the thickest point of the second region 1112 is the maximum thickness of the second region 1112. For example, if the second region 1112 has a uniform thickness structure, the thickness at any point in the second region 1112 can be considered the maximum thickness of the second region 1112.

[0301] In this embodiment, a portion of the first region 1111 may protrude from the first inner surface 11121 and / or the first outer surface 11122. For example, in the embodiment shown in Figures 22-24, a portion of the first region 1111 protrudes from the first outer surface 11122, and the inner surface of the first region 1111 is coplanar with the first inner surface 11121.

[0302] The maximum distance between the first outer surfaces 11122 of the second region 1112 of two opposing first walls 111 of case 11 is the size of case 11 along the second direction Y. To understand this, when measuring the size of case 11 along the second direction Y, the reference point is the first outer surface 11122 of the second region 1112. For example, the first outer surfaces 11122 of the second region 1112 of two opposing first walls 111 are installed parallel to each other.

[0303] In the case of the steel case 11, D1 / D can take the value of any one of the following points, or a range value between any two of them, such as 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.01, 0.011, 0.012, etc.

[0304] In the case of a steel case 11, if D1 / D ≥ 0.001, the ratio of the thickness of the second region 1112 to the case 11 is increased, providing sufficient strength to the second region 1112 and satisfying the strength requirements of the case 11. If D1 / D ≤ 0.012, the ratio of the thickness of the second region 1112 to the case 11 is decreased, and if the volume of the case 11 is constant, the internal space of the case 11 is increased, further leaving more space for the electrode assembly 2 and satisfying the requirements for the volumetric energy density of the battery cell 10.

[0305] In the case of a steel case 11, in order to meet the requirements for the volumetric energy density of the battery cell 10, D1 / D must be controlled to 0.012 or less. If the entire thickness of the first wall 111 is the same as the thickness of the second region 1112, the first wall 111 is prone to deformation when subjected to the expansion force of the electrode assembly 2, and over time this causes fatigue and cracking in the region of the first wall 111 located near the first connection 51. Therefore, a thicker first region 1111 is installed in the first wall 111 to strengthen the region of the first wall 111 located near the first connection 51 via the first region 1111, thereby reducing the risk of fatigue cracking.

[0306] In some embodiments, the material of case 11 includes steel. The maximum thickness of the second region 1112 is D1, where 0.08 mm ≤ D1 ≤ 0.35 mm, and / or the maximum thickness of the first region 1111 is D2, where 0.1 mm ≤ D2 ≤ 0.6 mm.

[0307] The thickness at the thickest point of the second region 1112 is the maximum thickness of the second region 1112. The thickness at the thickest point of the first region 1111 is the maximum thickness of the first region 1111. As can be seen, the maximum thickness of the second region 1112 is less than the maximum thickness of the first region 1111, i.e., D1 <D2である。

[0308] In the case of a steel case 11, D1 can take the value of any one point or a range between any two of the following: 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.25 mm, 0.28 mm, 0.3 mm, 0.32 mm, 0.35 mm, etc., and D2 can take the value of any one point or a range between any two of the following: 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, etc.

[0309] In the case of a steel case 11, setting the maximum thickness of the second region 1112 to 0.08 mm to 0.35 mm not only satisfies the strength requirements of the second region 1112 but also satisfies the volumetric energy density requirements of the battery cell 10. Setting the maximum thickness of the first region 1111 to 0.1 mm to 0.6 mm provides sufficient strength to the first region 1111 and strengthens the strength of the region located near the first connection 51 of the first wall 111.

[0310] In some embodiments, the material of case 11 includes an aluminum alloy. The maximum thickness of the second region 1112 is D1, and the size of case 11 along the second direction Y is D, where 0.005 ≤ D1 / D ≤ 0.065.

[0311] In the case of case 11, which is made of aluminum alloy, D1 / D can take the value of any one point or a range value between any two of the following: 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.055, 0.06, 0.065, etc.

[0312] In the case of case 11 made of aluminum alloy, if D1 / D ≥ 0.005, the ratio of the thickness of the second region 1112 in case 11 is increased, giving the second region 1112 sufficient strength and meeting the strength requirements of case 11. If D1 / D ≤ 0.065, the ratio of the thickness of the second region 1112 in case 11 is decreased, and if the volume of case 11 is constant, the internal space of case 11 is increased, further leaving more space for the electrode assembly 2 and meeting the requirements for the volumetric energy density of the battery cell 10.

[0313] In the case of the case 11 made of aluminum alloy, in order to meet the requirements for the volumetric energy density of the battery cell 10, D1 / D must be controlled to 0.065 or less. If the entire thickness of the first wall 111 is the same as the thickness of the second region 1112, the first wall 111 is prone to deformation when subjected to the expansion force of the electrode assembly 2, and over time this causes fatigue and cracking in the region of the first wall 111 located near the first connection 51. Therefore, a thicker first region 1111 is installed in the first wall 111 to strengthen the region of the first wall 111 located near the first connection 51 via the first region 1111, thereby reducing the risk of fatigue cracking.

[0314] In some embodiments, the material of case 11 includes an aluminum alloy. The maximum thickness of the second region 1112 is D1, where 0.4 mm ≤ D1 ≤ 0.8 mm, and / or the maximum thickness of the first region 1111 is D2, where 0.5 mm ≤ D2 ≤ 1.5 mm.

[0315] In the case of case 11 made of aluminum alloy, D1 can take the value of any one point or a range between any two of the following: 0.4mm, 0.42mm, 0.45mm, 0.48mm, 0.5mm, 0.52mm, 0.55mm, 0.58mm, 0.6mm, 0.62mm, 0.65mm, 0.68mm, 0.7mm, 0.72mm, 0.75mm, 0.78mm, 0.8mm, etc., and D2 can take the value of any one point or a range between any two of the following: 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0316] In the case of case 11 made of aluminum alloy, setting the maximum thickness of the second region 1112 to 0.4 mm to 0.8 mm not only satisfies the strength requirements of the second region 1112 but also satisfies the volumetric energy density requirements of the battery cell 10. Setting the maximum thickness of the first region 1111 to 0.5 mm to 1.5 mm provides sufficient strength to the first region 1111 and strengthens the strength of the region located near the first connection 51 of the first wall 111.

[0317] In some embodiments, the aluminum alloy contains, by mass percentage, aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%. Such aluminum alloys have good workability and facilitate the forming of case 11.

[0318] In some embodiments, the aluminum alloy contains, by mass percentage, aluminum ≥ 96.7%, copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single elemental components ≤ 0.05%, and total components of other elements ≤ 0.15%. Such aluminum alloys have good workability and corrosion resistance.

[0319] In some embodiments, referring to Figures 25 and 26, Figure 25 is a partial view of a battery cell 10 according to some other embodiments of the present application (showing the first wall 111), and Figure 26 is a partial enlarged view of area C in Figure 25. The first region 1111 is directly connected to the first connection portion 51.

[0320] The first region 1111 and the first connection portion 51 may be in point contact, line contact, or surface contact, thereby achieving direct connection between the two.

[0321] In this embodiment, the first region 1111 is directly connected to the first connection portion 51, bringing the first region 1111 and the first connection portion 51 closer together along the first direction Z, positioning the first region 1111 near the first connection portion 51, and further reducing the risk of the region of the first wall 111 located near the first connection portion 51 becoming fatigued and cracking due to the expansion of the electrode assembly 2.

[0322] In some embodiments, the first wall 111 further includes a first transition region 1117, the first transition region 1117 being connected to one end of the first region 1111 away from the second region 1112 along a first direction Z, the first transition region 1117 being connected to a first connection portion 51, the connection position between the first transition region 1117 and the first connection portion 51 forming a first connection interface 511, the first connection interface 511 having a first position 5111 that is closest to the first region 1111 along a first direction Z, the first position 5111 being located at one end of the first region 1111 away from the second region 1112 along a first direction Z.

[0323] The first transition region 1117 may be the portion where the first wall 111 is connected between the first connection portion 51 and the first region 1111. The first transition region 1117 may have a uniform thickness structure or a non-uniform thickness structure. The thickness of the first transition region 1117 may be less than the thickness of the first region 1111. For example, in the embodiment shown in Figures 25 and 26, the thickness of the first transition region 1117 gradually decreases along the direction in which the second region 1112 moves toward the first region 1111.

[0324] The first connection interface 511 is formed at the connection position between the first transition region 1117 and the first connection portion 51, and the first transition region 1117 and the first connection portion 51 are bounded by the first connection interface 511. The first connection interface 511 may be a plane or a curved surface.

[0325] The first region 1111 and the first transition region 1117 are bounded by a first boundary surface U, the first boundary surface U is a virtual plane, the first boundary surface U passes through the first position 5111, the first boundary surface U is perpendicular to the first direction Z, the first transition region 1117 and the first connection 51 are located above the first boundary surface U, and the first region 1111 is located below the first boundary surface U.

[0326] In this embodiment, the first transition region 1117 is connected to the first connecting portion 51 to form a first connecting interface 511, thereby providing a sufficiently large contact area between the first transition region 1117 and the first connecting portion 51, and improving the robustness of the welded connection between the first wall 111 and the end cap 12.

[0327] In some embodiments, at least a portion of the first connection interface 511 extends inclined with respect to the second direction Y.

[0328] The first connecting interface 511 may extend in a manner that is inclined with respect to the second direction Y as a whole, or it may extend in a manner that is inclined with respect to the second direction Y as a partial extent.

[0329] To make it clear, the extension direction of the portion of the first connection interface 511 that extends at an angle with respect to the second direction Y is not parallel to the second direction Y.

[0330] After the end cap 12 and the first wall 111 are welded together, the first connection portion 51 shrinks as it solidifies, generating tensile stress on the first transition region 1117. When the first wall 111 is subjected to the expansion force of the electrode assembly 2, the first wall 111 deforms, generating tensile stress on the first transition region 1117. Since at least a portion of the first connection interface 511 extends inclined with respect to the second direction Y, the tensile stress generated on the first transition region 1117 by the contraction of the first connection portion 51 and the tensile stress generated on the first connection portion 51 by the deformation of the first wall 111 are not on the same line near the portion of the first connection interface 511 that extends inclined with respect to the second direction Y, thereby reducing the risk of fatigue and cracking in the region of the first transition region 1117 located near the first connection interface 511.

[0331] In some embodiments, continuing with reference to Figure 26, the first connecting interface 511 includes a first interface 5112, which extends inclined toward approaching the end cap 12 from the first position 5111, and along the second direction Y, at least a portion of the first transition region 1117 is located between the first interface 5112 and the end cap 12.

[0332] To make it clear, the first interface 5112 extends at an inclination with respect to the second direction Y. The first interface 5112 may be a plane or a curved surface.

[0333] The first position 5111 is the lowest position of the first interface 5112 (the position closest to the first region 1111), and the first interface 5112 extends inclined from the first position 5111 toward the end cap 12, that is, the first interface 5112 extends diagonally upward toward the end cap 12 from the first position 5111.

[0334] Along the second direction Y, the first transition region 1117 may be entirely located between the first interface 5112 and the end cap 12, or only a portion of the first transition region 1117 may be located between the first interface 5112 and the end cap 12.

[0335] In this embodiment, along the second direction Y, at least a portion of the first transition region 1117 is located between the first interface 5112 and the end cap 12, and in this way the first connector 51 provides protection to the first transition region 1117, and when the first wall 111 is subjected to the expansion force of the electrode assembly 2, deformation of the first transition region 1117 is prevented by the first connector 51 during the process of being subjected to the force, thereby reducing the risk of fatigue and cracking of the region of the first transition region 1117 located near the first interface 5112.

[0336] In some embodiments, continuing with reference to Figure 26, the first interface 5112 connects the outer surface of the first region 1111 to the first position 5111.

[0337] For example, the first interface 5112 intersects the outer surface of the first region 1111 with the first straight line, the first straight line extends along the third direction X, and the location of the first straight line is the first position 5111. The first interface 5112 connects the inner surface of the first transition region 1117 with the third position 5114, and along the first direction Z, the third position 5114 is further from the first region 1111 than the first position 5111. The first transition region 1117 is approximately triangular in shape.

[0338] In this embodiment, the first interface 5112 is connected to the outer surface of the first region 1111 and the first position 5111, directly connecting the first region 1111 and the first connection portion 51, bringing the first region 1111 and the first connection portion 51 closer together along the first direction Z, and further reducing the risk of the region of the first wall 111 located near the first connection portion 51 becoming fatigued and cracking due to the expansion of the electrode assembly 2.

[0339] In some embodiments, referring to Figures 27 and 28, Figure 27 is a partial view of a battery cell 10 (showing the first wall 111) according to yet another embodiment of the present application, and Figure 28 is a partial enlarged view of location D in Figure 27. The first connection interface 511 includes a second interface 5113, which extends inclined from the first position 5111 toward the end cap 12, and along the second direction Y, at least a portion of the first transition region 1117 is located on one side of the second interface 5113 toward the end cap 12.

[0340] To make it clear, the second interface 5113 extends at an inclination with respect to the second direction Y. The second interface 5113 may be a plane or a curved surface. Along the second direction Y, at least a portion of the first connection 51 is located between the second interface 5113 and the end cap 12.

[0341] The first position 5111 is the lowest position of the second interface 5113 (the position closest to the first region 1111), and the second interface 5113 extends inclined from the first position 5111 away from the end cap 12, that is, the second interface 5113 extends diagonally upward from the first position 5111 away from the end cap 12.

[0342] Along the second direction Y, the first transition region 1117 may be entirely located on one side away from the end cap 12 of the second interface 5113, or only a portion of the first transition region 1117 may be located on one side away from the end cap 12 of the second interface 5113.

[0343] In this embodiment, along the second direction Y, at least a portion of the first transition region 1117 is located on one side away from the end cap 12 of the second interface 5113, thereby allowing the first transition region 1117 to act as a limiting force on the first connection 51 and reducing the risk of the first connection 51 falling off.

[0344] In some embodiments, continuing to refer to Figure 28, the second interface 5113 connects to the inner surface of the first region 1111 and the first position 5111.

[0345] For example, the second interface 5113 intersects the inner surface of the first region 1111 with the first straight line, the first straight line extends along the third direction X, and the location of the first straight line is the first position 5111. The second interface 5113 connects the outer surface of the first transition region 1117 with the fourth position 5115, and along the first direction Z, the fourth position 5115 is further from the first region 1111 than the first position 5111. The first transition region 1117 is approximately triangular in shape.

[0346] In this embodiment, the second interface 5113 is connected to the inner surface of the first region 1111 and the first position 5111, directly connecting the first region 1111 and the first connection portion 51, bringing the first region 1111 and the first connection portion 51 closer together along the first direction Z, and further reducing the risk of fatigue and cracking of the region of the first wall 111 located near the first connection portion 51 due to expansion of the electrode assembly 2.

[0347] In some embodiments, referring to Figures 29 and 30, Figure 29 is a partial view of a battery cell 10 according to some further embodiments of the present application (showing the first wall 111), and Figure 30 is a partial enlarged view of location E in Figure 29. The first connection interface 511 includes a first interface 5112 and a second interface 5113, the first interface 5112 extending inclined toward the end cap 12 from the first position 5111, and the second interface 5113 extending inclined toward the end cap 12 from the first position 5111, along the second direction Y, a portion of the first transition region 1117 is located between the first interface 5112 and the end cap 12, and the other portion of the first transition region 1117 is located on one side of the second interface 5113 toward the end cap 12.

[0348] For example, the first interface 5112 is connected to the inner surface of the first transition region 1117 and to the third position 5114, and the second interface 5113 is connected to the outer surface of the first transition region 1117 and to the fourth position 5115.

[0349] In some embodiments, the Vickers hardness of the first transition region 1117 is less than that of the second region 1112, and / or the Vickers hardness of the first transition region 1117 is less than that of the first connection 51.

[0350] For example, the Vickers hardness of the second region 1112 is less than that of the first connection 51.

[0351] If the Vickers hardness of the first transition region 1117 is lower than that of the second region 1112, the first transition region 1117, which has a lower Vickers hardness, can be connected to the first connection 51, thereby easing the stiffness tension between it and the first connection 51 when the first wall 111 deforms, and reducing the risk of the first wall 111 and the first connection 51 separating. If the Vickers hardness of the first transition region 1117 is lower than that of the first connection 51, the first transition region 1117 becomes more easily deformable than the first connection 51, thereby easing the stiffness tension between it and the first connection 51 when the first wall 111 deforms, and reducing the risk of the first wall 111 and the first connection 51 separating.

[0352] In some embodiments, continuing to refer to Figures 25-30, along the first direction Z, the first connecting interface 511 is closer to the second region 1112 than to the outer surface 121 of the end cap.

[0353] Along the first direction Z, the surface of the end cap 12 away from the electrode assembly 2 is the outer surface 121 of the end cap.

[0354] In the embodiments shown in Figures 25 and 26, along the first direction Z, both the third position 5114 and the first position 5111 are closer to the second region 1112 than to the outer surface 121 of the end cap.

[0355] In the embodiments shown in Figures 27 and 28, along the first direction Z, both the fourth position 5115 and the first position 5111 are closer to the second region 1112 than to the outer surface 121 of the end cap.

[0356] In the embodiments shown in Figures 29 and 30, along the first direction Z, the third position 5114, the fourth position 5115, and the first position 5111 are all closer to the second region 1112 than to the outer surface 121 of the end cap.

[0357] In this embodiment, the first connection interface 511 is closer to the second region 1112 along the first direction Z than the outer surface 121 of the end cap, thereby allowing the first connection portion 51 to sink deeper into the first wall 111, and effectively improving the connection strength between the first wall 111 and the end cap 12.

[0358] In some embodiments, referring to Figures 31 and 32, Figure 31 is a perspective view of Case 11 according to some further embodiments of the present application, and Figure 32 is a partial enlargement of location F in Figure 31. Case 11 further includes a second wall 112 and a corner wall 113, the first wall 111, the corner wall 113 and the second wall 112 are arranged along the circumferential direction of the opening, and the corner wall 113 connects the first wall 111 and the second wall 112.

[0359] The second wall 112 and the end cap 12 can be welded together to form a third connection 5, and both the first connection 51 and the third connection 5 are part of the connection 5. The second wall 112 may have a uniform thickness structure or a non-uniform thickness structure.

[0360] In the embodiments shown in Figures 31 and 32, the second wall 112 has a uniform thickness structure. In other embodiments, the second wall 112 may have a non-uniform thickness structure, and the structure of the second wall 112 may be the same as the structure of the first wall 111. For example, the second wall 112 includes a fifth and a sixth region arranged along the first direction Z, the thickness of the fifth region being greater than the thickness of the sixth region, and the fifth region being located between the third connection 5 and the sixth region, thereby reducing the risk of fatigue and cracking of the region of the second wall 112 located near the third connection 5. Here, the structure of the fifth region may be the same as the structure of the first region 1111, and the structure of the sixth region may be the same as the structure of the second region 1112.

[0361] In case 11, the first wall 111 and the second wall 112 are indirectly connected via the corner wall 113, and the sum of the number of first walls 111 and second walls 112 is equal to the number of corner walls 113.

[0362] For example, the first wall 111, the second wall 112, and the corner wall 113 are integrally molded. The outer and / or inner cross-sections of the corner wall 113 may be arc-shaped, and these cross-sections are perpendicular to the first direction Z.

[0363] In this embodiment, the first wall 111 and the second wall 112 are connected via a corner wall 113, so that the first wall 111 can transition to the second wall 112 via the corner wall 113, effectively reducing the risk of stress concentration occurring at the corner location of case 11.

[0364] In some embodiments, referring to Figures 33-35, Figure 33 is a partial view of a battery cell 10 according to some embodiments of the present application (showing a corner wall 113), Figure 34 is a schematic structural diagram of a corner wall 113 according to some embodiments of the present application, and Figure 35 is a schematic structural diagram of a corner wall 113 according to another embodiment of the present application. The corner wall 113 is welded to the end cap 12 to form a second connection 52. The corner wall 113 includes a third region 1131 and a fourth region 1132 arranged along a first direction Z, the thickness of the third region 1131 being greater than the thickness of the fourth region 1132, and the third region 1131 being located between the fourth region 1132 and the second connection 52.

[0365] The third region 1131 may be a region where the thickness of the corner wall 113 is increased, and the third region 1131 may be thicker than the fourth region 1132, and the fourth region 1132 may be a portion located on one side of the third region 1131 away from the second connection portion 52 along the first direction Z of the corner wall 113. The third region 1131 and the second connection portion 52 may be directly connected or indirectly connected, and the third region 1131 and the fourth region 1132 may be directly connected or indirectly connected. The third region 1131 may be a uniform thickness structure or a non-uniform thickness structure, and the fourth region 1132 may be a uniform thickness structure or a non-uniform thickness structure. If at least one of the third region 1131 and the fourth region 1132 has a non-uniform thickness structure, the maximum thickness of the third region 1131 may be less than or equal to the minimum thickness of the fourth region 1132, thereby achieving that the thickness of the third region 1131 is greater than the thickness of the fourth region 1132.

[0366] The fourth region 1132 has a second inner surface 11321 facing the internal space of the case 11 and a second outer surface 11322 away from the internal space of the case 11, and the third region 1131 may have a portion protruding from the second inner surface 11321 and / or the second outer surface 11322. For example, in the embodiments shown in Figures 33 and 34, a portion of the third region 1131 protrudes from the second inner surface 11321 and the outer surface of the third region 1131 is coplanar with the second outer surface 11322, and in the embodiment shown in Figure 35, a portion of the third region 1131 protrudes from the second outer surface 11322 and the inner surface of the third region 1131 is coplanar with the second inner surface 11321.

[0367] The second connection portion 52 may correspond one-to-one with the corner wall 113, and the second connection portion 52 may be the portion where a weld mark is formed after the end cap 12 and the corner wall 113 are welded together, or the portion where the end cap 12 and the corner wall 113 are welded together and fused as one. Part of the second connection portion 52 is formed on the end cap 12, and the other part of the second connection portion 52 is formed on the corner wall 113. The corner wall 113 and the end cap 12 may form the second connection portion 52 by overlap seam welding or by through welding. Both the second connection portion 52 and the first connection portion 51 are parts of the connection portion 5.

[0368] The thickness of the third region 1131 is greater than the thickness of the fourth region 1132, and the third region 1131 is located between the second connection 52 and the fourth region 1132. As a result, the thicker third region 1131 is closer to the second connection 52 than the fourth region 1132, and the third region 1131 provides a reinforcing effect on the region of the corner wall 113 located near the second connection 52, reducing the risk of fatigue and cracking of the region of the corner wall 113 located near the second connection 52, and further improving the service life of the battery cell 10.

[0369] In some embodiments, referring again to Figure 32, the third region 1131 is directly connected to the first region 1111.

[0370] For example, the third region 1131 is integrally molded with the first region 1111, and the third region 1131 is connected to both ends of the first region 1111 along the third direction X.

[0371] In embodiments where the second wall 112 includes the fifth and sixth regions, the third region 1131 may connect the first region 1111 and the fifth region, and the fourth region 1132 may connect the second region 1112 and the sixth region.

[0372] By directly connecting the third region 1131 and the first region 1111, the first region 1111 and the third region 1131 are integrated, and the third region 1131 and the first region 1111 have a mutually reinforcing effect, improving the reinforcing effect of the first wall 111 of the first region 1111 and the reinforcing effect of the corner wall 113 of the second region 1112.

[0373] In some embodiments, continuing with reference to Figure 32, along the circumferential direction of the opening, the corner wall 113 has a first connecting end 1133 and a second connecting end 1134, the first wall 111 is connected to the first connecting end 1133, the second wall 112 is connected to the second connecting end 1134, and the thickness of the third region 1131 tends to decrease along the direction from the first connecting end 1133 toward the second connecting end 1134.

[0374] For example, the thickness of the third region 1131 gradually decreases along the direction from the first connecting end 1133 toward the second connecting end 1134, the second wall 112 has a uniform thickness structure, the inner surface of the third region 1131 is connected to the inner surface of the first region 1111 and the inner surface of the second wall 112, and the outer surface of the third region 1131 is connected to the outer surface of the first region 1111 and the outer surface of the second wall 112.

[0375] When the first wall 111 is subjected to the expansion force of the electrode assembly 2 in the second direction Y, the first wall 111 may deform and deform the corner wall 113. The closer the corner wall 113 is to the first wall 111 along the circumferential direction of the opening, the greater the influence of the first wall 111 on the corner wall 113, and the greater the amount of deformation in the region of the corner wall 113 that is close to the first wall 111. The thickness of the third region 1131 tends to decrease along the direction from the first connection end 1133 toward the second connection end 1134, increasing the strength of the region of the third region 1131 that is close to the first wall 111 along the circumferential direction of the opening, further reducing the influence of the deformation of the first wall 111 on the corner wall 113, providing sufficient strength to the vicinity region located at the second connection part 52 of the corner wall 113, while simultaneously reducing the amount of material used in the third region 1131 and lowering production costs.

[0376] In some embodiments, referring to Figures 36 and 37, Figure 36 is a partial view of a battery cell 10 (showing a corner wall 113) according to some other embodiments of the present application, and Figure 37 is a partial enlarged view of area G in Figure 36. The third area 1131 is directly connected to the second connection 52.

[0377] The third region 1131 and the second connection portion 52 may be in point contact, line contact, or surface contact, thereby achieving direct connection between the two.

[0378] In this embodiment, the third region 1131 is directly connected to the second connection portion 52, bringing the third region 1131 and the second connection portion 52 closer together along the first direction Z, positioning the third region 1131 near the second connection portion 52, and further reducing the risk of fatigue and cracking of the region of the corner wall 113 located near the second connection portion 52.

[0379] In some embodiments, the corner wall 113 further includes a second transition region 1135, which is connected to one end of the third region 1131 away from the fourth region 1132 along a first direction Z, and the second transition region 1135 is connected to a second connection 52, the connection position between the second transition region 1135 and the second connection 52 forms a second connection interface 521, the second connection interface 521 has a second position 5211 that is closest to the third region 1131 along the first direction Z, and the second position 5211 is located at one end of the third region 1131 away from the fourth region 1132 along the first direction Z.

[0380] The second transition region 1135 may be the portion where the corner wall 113 is connected between the second connection 52 and the third region 1131. The second transition region 1135 may have a uniform thickness structure or a non-uniform thickness structure. The thickness of the second transition region 1135 may be less than the thickness of the third region 1131. For example, in the embodiment shown in Figures 36 and 37, the thickness of the second transition region 1135 gradually decreases along the direction in which the fourth region 1132 moves toward the third region 1131.

[0381] The second connection interface 521 is formed at the connection point between the second transition region 1135 and the second connection portion 52, and the second transition region 1135 and the second connection portion 52 are bounded by the second connection interface 521. The second connection interface 521 may be a plane or a curved surface.

[0382] The third region 1131 and the second transition region 1135 are bounded by a second boundary surface V, which is a virtual plane, passes through the second position 5211, is perpendicular to the first direction Z, the second transition region 1135 and the second connection 52 are located above the second boundary surface V, and the third region 1131 is located below the second boundary surface V.

[0383] In this embodiment, the second transition region 1135 is connected to the second connection portion 52 to form a second connection interface 521, thereby providing a sufficiently large contact area between the second transition region 1135 and the second connection portion 52, improving the robustness of the welded corner wall 113 and end cap 12.

[0384] In some embodiments, at least a portion of the second connection interface 521 extends inclined with respect to the thickness direction of the corner wall 113.

[0385] The second connecting interface 521 may extend inclined with respect to the thickness direction of the corner wall 113 as a whole, or the second connecting interface 521 may extend inclined with respect to the thickness direction of the corner wall 113 in a localized manner.

[0386] In the vicinity of the portion where the second connection interface 521 extends inclined with respect to the thickness direction of the corner wall 113, the tensile stress generated in the second transition region 1135 by the contraction of the second connection portion 52 and the tensile stress generated in the second connection portion 52 by the deformation of the corner wall 113 are not on the same line, thereby reducing the risk of fatigue and cracking in the region of the second transition region 1135 located near the second connection interface 521.

[0387] In some embodiments, continuing with reference to Figure 37, the second connecting interface 521 includes a third interface 5212, which extends inclined from the second position 5211 toward approaching the end cap 12, and along the thickness direction of the corner wall 113, at least a portion of the second transition region 1135 is located between the third interface 5212 and the end cap 12.

[0388] To make it clear, the third interface 5212 extends inclined with respect to the thickness direction of the corner wall 113. The third interface 5212 may be a plane or a curved surface.

[0389] The second position 5211 is the lowest position of the third interface 5212 (the position closest to the third region 1131), and the third interface 5212 extends inclined from the second position 5211 toward the end cap 12, that is, the third interface 5212 extends diagonally upward toward the end cap 12 from the second position 5211.

[0390] Along the thickness direction of the corner wall 113, the second transition region 1135 may be entirely located between the third interface 5212 and the end cap 12, or only a portion of the second transition region 1135 may be located between the third interface 5212 and the end cap 12.

[0391] In this embodiment, along the thickness direction of the corner wall 113, at least a portion of the second transition region 1135 is located between the third interface 5212 and the end cap 12, and the second connector 52 provides protection to the second transition region 1135, preventing outward deformation of the second transition region 1135, thereby reducing the risk of fatigue and cracking of the region of the second transition region 1135 located near the third interface 5212.

[0392] In some embodiments, continuing to refer to Figure 37, the third interface 5212 connects the outer surface of the third region 1131 to the second position 5211.

[0393] For example, the third interface 5212 intersects the outer surface of the third region 1131 with the second line, the second line extends along the third direction X, and the location of the second line is the second position 5211. The third interface 5212 connects the inner surface of the second transition region 1135 with the fifth position 5214, and along the first direction Z, the fifth position 5214 is further from the third region 1131 than the second position 5211. The second transition region 1135 is approximately triangular in shape.

[0394] In this embodiment, the third interface 5212 is connected to the outer surface of the third region 1131 and the second position 5211, thereby creating a direct connection between the third region 1131 and the second connection 52. This brings the third region 1131 and the second connection 52 closer together along the first direction Z, further reducing the risk of fatigue and cracking in the area of ​​the corner wall 113 located near the second connection 52.

[0395] In some embodiments, referring to Figures 38 and 39, Figure 38 is a partial view of a battery cell 10 (showing a corner wall 113) according to yet another embodiment of the present application, and Figure 39 is a partial enlarged view of location H in Figure 38. The second connection interface 521 includes a fourth interface 5213, which extends inclined from the second position 5211 toward the end cap 12, and along the thickness direction of the corner wall 113, at least a portion of the second transition region 1135 is located on one side of the fourth interface 5213 toward the end cap 12.

[0396] To make it clear, the fourth interface 5213 extends at an inclination with respect to the second direction Y. The fourth interface 5213 may be a plane or a curved surface. Along the thickness direction of the corner wall 113, at least a portion of the second connection 52 is located between the fourth interface 5213 and the end cap 12.

[0397] The second position 5211 is the lowest position of the fourth interface 5213 (the position closest to the first region 1111), and the fourth interface 5213 extends inclined from the second position 5211 away from the end cap 12, that is, the fourth interface 5213 extends diagonally upward from the second position 5211 away from the end cap 12.

[0398] Along the thickness direction of the corner wall 113, the second transition region 1135 may be located entirely on one side away from the end cap 12 of the fourth interface 5213, or only a portion of the second transition region 1135 may be located on one side away from the end cap 12 of the fourth interface 5213.

[0399] In this embodiment, along the thickness direction of the corner wall 113, at least a portion of the second transition region 1135 is located on one side away from the end cap 12 of the fourth interface 5213, thereby the second transition region 1135 acts as a limiting force on the second connection 52, reducing the risk of the second connection 52 falling off.

[0400] In some embodiments, the fourth interface 5213 is connected to the inner surface of the third region 1131 and the second position 5211.

[0401] For example, the fourth interface 5213 intersects the inner surface of the third region 1131 with the second line, the second line extends along the third direction X, and the location of the second line is the second position 5211. The fourth interface 5213 connects the outer surface of the second transition region 1135 with the sixth position 5215, and along the first direction Z, the sixth position 5215 is further from the third region 1131 than the second position 5211. The second transition region 1135 is approximately triangular in shape.

[0402] In this embodiment, the fourth interface 5213 is connected to the inner surface of the third region 1131 and the second position 5211, thereby creating a direct connection between the third region 1131 and the second connection 52. This brings the third region 1131 and the second connection 52 closer together along the first direction Z, further reducing the risk of fatigue and cracking in the region of the corner wall 113 located near the second connection 52.

[0403] In some embodiments, referring to Figures 40 and 41, Figure 40 is a partial view of a battery cell 10 (showing a corner wall 113) according to some further embodiments of the present application, and Figure 41 is a partial enlarged view of location I in Figure 40. The second connection interface 521 includes a third interface 5212 and a fourth interface 5213, the third interface 5212 extending inclined toward the end cap 12 from the second position 5211, and the fourth interface 5213 extending inclined toward the end cap 12 from the second position 5211, along the thickness direction of the corner wall 113, a portion of the second transition region 1135 is located between the third interface 5212 and the end cap 12, and the other portion of the second transition region 1135 is located on one side of the fourth interface 5213 away from the end cap 12.

[0404] For example, the third interface 5212 is connected to the inner surface of the second transition region 1135 and the fifth position 5214, and the fourth interface 5213 is connected to the outer surface of the second transition region 1135 and the sixth position 5215.

[0405] In some embodiments, the Vickers hardness of the second transition region 1135 is less than that of the fourth region 1132, and / or the Vickers hardness of the second transition region 1135 is less than that of the second connection 52.

[0406] For example, the Vickers hardness of the fourth region 1132 is less than that of the second connection 52.

[0407] If the Vickers hardness of the second transition region 1135 is lower than that of the fourth region 1132, the second transition region 1135, which has a lower Vickers hardness, can be connected to the second connection 52, thereby easing the rigid tension between it and the second connection 52 when the corner wall 113 deforms, and reducing the risk of the corner wall 113 and the second connection 52 separating. If the Vickers hardness of the second transition region 1135 is lower than that of the second connection 52, the second transition region 1135 becomes more deformable than the second connection 52, thereby easing the rigid tension between it and the second connection 52 when the corner wall 113 deforms, and reducing the risk of the corner wall 113 and the second connection 52 separating.

[0408] In some embodiments, referring to Figures 36-41, along the first direction Z, the second connection interface 521 is closer to the fourth region 1132 than to the outer surface 121 of the end cap.

[0409] In the embodiments shown in Figures 36 and 37, along the first direction Z, both the fifth position 5214 and the second position 5211 are closer to the fourth region 1132 than to the outer surface 121 of the end cap.

[0410] In the embodiments shown in Figures 38 and 39, along the first direction Z, both the sixth position 5215 and the second position 5211 are closer to the second region 1112 than to the outer surface 121 of the end cap.

[0411] In the embodiments shown in Figures 40 and 41, along the first direction Z, the fifth position 5214, the sixth position 5215, and the second position 5211 are all closer to the second region 1112 than to the outer surface 121 of the end cap.

[0412] In this embodiment, the second connection interface 521 is closer to the fourth region 1132 along the first direction Z than the outer surface 121 of the end cap, allowing the second connection portion 52 to sink deeper into the corner wall 113, thereby effectively improving the connection strength between the corner wall 113 and the end cap 12.

[0413] In some embodiments, continuing to refer to Figure 31, case 11 includes two first walls 111 and two second walls 112, where the two first walls 111 are positioned opposite each other along a second direction Y, and the two second walls 112 are positioned opposite each other along a third direction X, with the first direction Z, the second direction Y, and the third direction X being perpendicular to each other in pairs.

[0414] Corner walls 113 are installed at both ends of the first wall 111 along the third direction X, and corner walls 113 are installed at both ends of the second wall 112 along the second direction Y. To make it clear, there are four corner walls 113 in case 11.

[0415] In this embodiment, the case 11 is substantially rectangular in shape, which allows for a larger size of the case 11 and is advantageous in meeting the requirements for a large capacity battery cell 10.

[0416] In some embodiments, the Vickers hardness of at least a portion of the first region 1111 is less than that of the second region 1112.

[0417] The Vickers hardness of the entire first region 1111 may be less than the Vickers hardness of the second region 1112, or the Vickers hardness of only a part of the first region 1111 may be less than the Vickers hardness of the second region 1112.

[0418] For example, the Vickers hardness of a portion of the first region 1111 is less than that of the second region 1112, the Vickers hardness of the rest of the first region 1111 is equal to that of the second region 1112, and the portion of the first region 1111 that is equal to the Vickers hardness of the second region 1112 is directly connected to the second region 1112.

[0419] When the second region 1112 deforms under the expansion force of the electrode assembly 2, the region in the first region 1111 with a lower Vickers hardness than the second region 1112 reduces the impact of the deformation of the second region 1112 on the region located near the first connection 51 of the first wall 111, thereby reducing the risk of the region located near the first connection 51 of the first wall 111 becoming fatigued and cracking due to the expansion of the electrode assembly 2.

[0420] In some embodiments, referring to Figure 42, which is a diagram of the positional relationship between the end cap 12 and the side wall before welding in some embodiments of the present application. Along the first direction Z, the first wall 111 has a position-restricting surface 1115 facing the end cap 12, the position-restricting surface 1115 abutting against the end cap 12 and restricting the end cap 12 from moving in the direction toward the electrode assembly 2.

[0421] The position regulating surface 1115 may be perpendicular to the first direction Z, the position regulating surface 1115 may be an end face at one end of the first wall 111 located at the opening of the case 11, the position regulating surface 1115 may be a stepped surface on the first wall 111, and a certain distance is separated between the stepped surface and the end face at one end of the first wall 111 located at the opening of the case 11.

[0422] The position-regulating surface 1115 acts as a position-regulating force for the end cap 12, reducing the risk of the end cap 12 moving in a direction closer to the electrode assembly 2 when welding to the case 11, effectively improving the welding quality between the end cap 12 and the case 11, and reducing the difficulty of welding the end cap 12 and the case 11.

[0423] In some embodiments, the first wall 111 further includes a position-regulating region 1116 installed on the position-regulating surface 1115, the position-regulating region 1116 being installed opposite the end cap 12 along a second direction Y, and the position-regulating region 1116 being welded to the end cap 12 to form a first connection 51.

[0424] For example, the end cap 12 is at least partially housed within the case 11, so that the position-restricting area 1116 and the end cap 12 are positioned opposite each other along the second direction Y.

[0425] After the position-restricting region 1116 is welded to the end cap 12, a portion of the position-restricting region 1116 and a portion of the end cap 12 may fuse together to form a first connection portion 51, and the remaining portion of the position-restricting region 1116 may form at least a portion of a first transition region 1117 (not shown in Figure 42).

[0426] The position-restricting region 1116 can also perform a position-restricting effect on the end cap 12, reducing the risk of movement along the thickness direction of the first wall 111 when welding the end cap 12 to the case 11, further improving the welding quality between the end cap 12 and the case 11, and reducing the difficulty of welding the end cap 12 to the case 11.

[0427] In some embodiments, the electrode assembly 2 is a laminated structure and includes a plurality of positive electrode plates 22 and a plurality of negative electrode plates 23, the plurality of positive electrode plates 22 and the plurality of negative electrode plates 23 are arranged in a stack along a second direction Y.

[0428] For example, in electrode assembly 2, the positive electrode plate 22 and the negative electrode plate 23 are arranged alternately along a second direction Y, and a separator member 24 is placed between the positive electrode plate 22 and the negative electrode plate 23.

[0429] In this embodiment, electrode assembly 2 is a wound electrode assembly, which has a more compact structure and relatively high pressure resistance.

[0430] In some embodiments, the number of negative electrode plates 23 is greater than the number of positive electrode plates 22, and one positive electrode plate 22 is placed between two adjacent negative electrode plates 23.

[0431] For example, there is one more negative electrode plate 23 than positive electrode plates 22.

[0432] In some embodiments, a negative electrode tab 21b is provided on each negative electrode plate 23 and / or a positive electrode tab 21a is provided on each positive electrode plate 22.

[0433] In some embodiments, along the third direction X, the size of the first region 1111 is larger than the size of the positive electrode plate 22 and / or the negative electrode plate 23, and the first direction Z, the second direction Y, and the third direction X are perpendicular to each other in pairs.

[0434] If the size of the first region 1111 is larger than the size of the positive electrode plate 22 along the third direction X, the first region 1111 extends beyond at least one end of the positive electrode plate 22 along the third direction X, and if the size of the first region 1111 is larger than the size of the negative electrode plate 23 along the third direction X, the first region 1111 extends beyond at least one end of the negative electrode plate 23 along the third direction X.

[0435] In this embodiment, along the third direction X, the size of the first region 1111 is larger than the size of the positive electrode plate 22 and / or the negative electrode plate 23, thereby increasing the size of the first region 1111 along the third direction X, which reinforces the strength of a larger area of ​​the first wall 111 along the third direction X, and further reduces the risk of fatigue and cracking of the area of ​​the first wall 111 located near the first connection 51.

[0436] Referring to Figure 43 in some embodiments, Figure 43 is a schematic diagram of the connection between an end cap 12 and an electrode terminal 3 according to some embodiments of the present application. The battery cell 10 further includes two electrode terminals 3, the two electrode terminals 3 being mounted on an end cap 12, the two electrode terminals 3 having opposite polarities and both being electrically connected to an electrode assembly 2, the end cap 12 being provided with a lead hole, the electrode terminal 3 including a terminal body 31, a first position restricting portion 32 and a second position restricting portion 33, the terminal body 31 being connected to the first position restricting portion 32 and the second position restricting portion 33, the terminal body 31 being drilled in a lead hole, the first position restricting portion 32 being located on one side of the end cap 12 away from the electrode assembly 2 along a first direction Z, and the second position restricting portion 33 being located on one side of the end cap 12 facing the electrode assembly 2.

[0437] The first position restricting portion 32 and the second position restricting portion 33 have a position restricting function, and the first position restricting portion 32 and the second position restricting portion 33 are each connected to both ends of the terminal body 31, and the first position restricting portion 32 and the second position restricting portion 33 cooperate to restrict the terminal body 31 from detaching from the lead hole. Along the first direction Z, the projected area of ​​the first position restricting portion 32 and the projected area of ​​the second position restricting portion 33 are both larger than the projected area of ​​the terminal body 31, and the projected area of ​​the first position restricting portion 32 may be larger than the projected area of ​​the second position restricting portion 33, and the projected area of ​​the second position restricting portion 33 may be larger than the projected area of ​​the first position restricting portion 32. The first position restricting portion 32, the second position restricting portion 33 and the terminal body 31 may be integrally molded, or one of the first position restricting portion 32 and the second position restricting portion 33 may be integrally molded with the terminal body 31, and the other may be installed separately from the terminal body 31 and connected.

[0438] For example, the battery cell 10 may further include a first insulating member 6 and a second insulating member 7, the first insulating member 6 being at least partially installed between the electrode terminals 3 and the end cap 12 to insulate and isolate the electrode terminals 3 and the end cap 12, and the second insulating member 7 being installed on one side of the end cap 12 facing the electrode assembly 2 to insulate and isolate the electrode assembly 2 and the end cap 12.

[0439] In this embodiment, the electrode terminal 3 can be attached to the end cap 12 by crimping, which reduces the difficulty of installation and offers better cost-effectiveness.

[0440] The embodiments of this application provide a battery 100 including a battery cell 10 according to any one of the embodiments described above.

[0441] Embodiments of this application provide a power-consuming device, which includes a battery cell 10 according to any one of the above embodiments, the battery cell 10 being used to provide electrical energy to the power-consuming device.

[0442] Embodiments of the present application further provide a battery cell 10 comprising a case 11, an end cap 12 and an electrode assembly 2, wherein an opening is formed at one end of the case 11 along a first direction Z, the end cap 12 is welded to the case 11 and seals the opening of the case 11, and the electrode assembly 2 is at least partially housed within the case 11. The case 11 is rectangular parallelepiped and comprises two first walls 111, two second walls 112 and four corner walls 113, wherein the first walls 111 are the walls with the largest outer surface area in the case 11, adjacent first walls 111 and second walls 112 are connected by one corner wall 113, the two first walls 111 are positioned opposite each other along a second direction Y, and the two second walls 112 are positioned opposite each other along a third direction X, with the first direction Z, the second direction Y and the third direction X being perpendicular in pairs. The electrode assembly 2 includes a positive electrode plate 22, a negative electrode plate 23, and a separator member 24, the separator member 24 being placed between the positive electrode plate 22 and the negative electrode plate 23, and the electrode assembly 2 has a flat region 25, the portion of the positive electrode plate 22 located in the flat region 25, the portion of the negative electrode plate 23 located in the flat region 25, and the portion of the separator member 24 located in the flat region 25 are stacked along the second direction Y. The electrode assembly 2 includes a first surface 27 perpendicular to the second direction Y, the first surface 27 being the largest surface area of ​​the outer surface of the electrode assembly 2, and the first wall 111 and the first surface 27 are positioned opposite each other along the second direction Y.

[0443] The first wall 111 is welded to the end cap 12 to form a first connection 51, and the first wall 111 includes a first region 1111 and a second region 1112 arranged along a first direction Z, the thickness of the first region 1111 is greater than the thickness of the second region 1112, and the first region 1111 is located between the first connection 51 and the second region 1112. The material of the case 11 includes an aluminum alloy, the maximum thickness of the second region 1112 is D1, the maximum thickness of the first region 1111 is D2, the size of the case 11 along a second direction Y is D, and 0.005 ≤ D1 / D ≤ 0.065, 0.4 mm ≤ D1 ≤ 0.8 mm, 0.5 mm ≤ D2 ≤ 1.5 mm. The corner wall 113 is welded to the end cap 12 to form a second connection 52, and the corner wall 113 includes a third region 1131 and a fourth region 1132 arranged along a first direction Z, the thickness of the third region 1131 being greater than the thickness of the fourth region 1132, and the third region 1131 is located between the fourth region 1132 and the second connection 52. The size of the first region 1111 along the third direction X is greater than the size of the second region 1112 along the first direction Z, and both ends of the first region 1111 along the third direction X are directly connected to the third region 1131 of the two corner walls 113. Along the circumferential direction of the opening, the corner wall 113 has a first connecting end 1133 and a second connecting end 1134, the first wall 111 is connected to the first connecting end 1133, the second wall 112 is connected to the second connecting end 1134, and the thickness of the third region 1131 tends to decrease along the direction from the first connecting end 1133 toward the second connecting end 1134. The first region 1111 includes a first portion 11111 and a second portion 11112 arranged along the first direction Z, the second portion 11112 connecting the first portion 11111 and the second region 1112, the thickness of the first portion 11111 is greater than the thickness of the second portion 11112, and the thickness of the second portion 11112 tends to decrease along the direction from the end cap 12 toward the electrode assembly 2.

[0444] The positive electrode plate 22 includes a positive electrode body region 221 and a positive electrode tab 21a protruding from the positive electrode body region 221, and the negative electrode plate 23 includes a negative electrode body region 231 and a negative electrode tab 21b protruding from the negative electrode body region 231. Along the first direction Z, the positive electrode body region 221 has a fifth end 2211 facing the end cap 12, the negative electrode body region 231 has a sixth end 2311 facing the end cap 12, and the separator member 24 has a seventh end 241 facing the end cap 12, the seventh end 241 being closer to the end cap 12 than the fifth end 2211 and the sixth end 2311. The separator member 24 includes an overhang region 242 that extends beyond the fifth end 2211 and the sixth end 2311 along the first direction Z, and in a projection plane perpendicular to the second direction Y, the overhang region 242 partially overlaps with the orthographic projection of the first region 1111. The first region 1111 includes a first projection 11118 that protrudes from the first inner surface 11121, and in a projection plane perpendicular to the second direction Y, the orthographic projections of the positive electrode body region 221 and the first projection 11118 do not overlap, and in a projection plane perpendicular to the second direction Y, the orthographic projections of the negative electrode body region 231 and the first projection 11118 do not overlap.

[0445] The first wall 111 further includes a first transition region 1117, the first transition region 1117 is connected to one end of the first region 1111 away from the second region 1112 along a first direction Z, the first transition region 1117 is connected to a first connection part 51, the connection position between the first transition region 1117 and the first connection part 51 forms a first connection interface 511, the first connection interface 511 has a first position 5111 that is closest to the first region 1111 along a first direction Z, the first position 5111 is located at one end of the first region 1111 away from the second region 1112 along a first direction Z. The first connecting interface 511 includes a second interface 5113, which extends inclined from the first position 5111 away from the end cap 12, and along the second direction Y, a portion of the first connecting portion 51 is located between the second interface 5113 and the end cap 12, and the second interface 5113 connects the inner surface of the first region 1111 to the first position 5111.

[0446] The corner wall 113 further includes a second transition region 1135, which is connected to one end of the third region 1131 away from the fourth region 1132 along a first direction Z, and the second transition region 1135 is connected to a second connection portion 52, the connection position between the second transition region 1135 and the second connection portion 52 forms a second connection interface 521, the second connection interface 521 has a second position 5211 that is closest to the third region 1131 along the first direction Z, and the second position 5211 is located at one end of the third region 1131 away from the fourth region 1132 along the first direction Z. The second connecting interface 521 includes a fourth interface 5213, which extends inclined from the second position 5211 away from the end cap 12, and along the thickness direction of the corner wall 113, a portion of the second connecting portion 52 is located between the fourth interface 5213 and the end cap 12, and the fourth interface 5213 connects the inner surface of the third region 1131 to the second position 5211.

[0447] Embodiments of the present application further provide a battery cell 10 comprising a case 11, an end cap 12 and an electrode assembly 2, wherein an opening is formed at one end of the case 11 along a first direction Z, the end cap 12 is welded to the case 11 and seals the opening of the case 11, and the electrode assembly 2 is at least partially housed within the case 11. The case 11 is rectangular parallelepiped and comprises two first walls 111, two second walls 112 and four corner walls 113, wherein the first walls 111 are the walls with the largest outer surface area in the case 11, adjacent first walls 111 and second walls 112 are connected by one corner wall 113, the two first walls 111 are positioned opposite each other along a second direction Y, and the two second walls 112 are positioned opposite each other along a third direction X, with the first direction Z, the second direction Y and the third direction X being perpendicular in pairs. The electrode assembly 2 includes a positive electrode plate 22, a negative electrode plate 23, and a separator member 24, the separator member 24 being placed between the positive electrode plate 22 and the negative electrode plate 23, and the electrode assembly 2 has a flat region 25, the portion of the positive electrode plate 22 located in the flat region 25, the portion of the negative electrode plate 23 located in the flat region 25, and the portion of the separator member 24 located in the flat region 25 are stacked along the second direction Y. The electrode assembly 2 includes a first surface 27 perpendicular to the second direction Y, the first surface 27 being the largest surface area of ​​the outer surface of the electrode assembly 2, and the first wall 111 and the first surface 27 are positioned opposite each other along the second direction Y.

[0448] The first wall 111 is welded to the end cap 12 to form a first connection 51, and the first wall 111 includes a first region 1111 and a second region 1112 arranged along a first direction Z, the thickness of the first region 1111 is greater than the thickness of the second region 1112, and the first region 1111 is located between the first connection 51 and the second region 1112. The material of the case 11 includes an aluminum alloy, the maximum thickness of the second region 1112 is D1, the maximum thickness of the first region 1111 is D2, the size of the case 11 along a second direction Y is D, and 0.005 ≤ D1 / D ≤ 0.065, 0.4 mm ≤ D1 ≤ 0.8 mm, 0.5 mm ≤ D2 ≤ 1.5 mm.

[0449] The size of the first region 1111 along the third direction X is greater than the size of the first region 1111 along the first direction Z. The first region 1111 includes a first portion 11111 and a second portion 11112 arranged along the first direction Z, the second portion 11112 connecting the first portion 11111 and the second region 1112, the thickness of the first portion 11111 is greater than the thickness of the second portion 11112, and the thickness of the second portion 11112 tends to decrease along the direction in which the end cap 12 is toward the electrode assembly 2.

[0450] Neither end of the first region 1111 along the third direction X is in contact with the corner wall 113. The first region 1111 includes a second connecting segment 11114, a first connecting segment 11113, and a third connecting segment 11115, which are arranged along the third direction X. The first connecting segment 11113 passes through the middle section, and the thickness of the first connecting segment 11113 is greater than the thickness of the second connecting segment 11114 and the third connecting segment 11115. The first connecting segment 11113 is connected to the second connecting segment 11114 and the third connecting segment 11115. The size of the first connecting segment 11113 along the third direction X is L1, and the size of the first wall 111 along the third direction X is L, where 0.2 ≤ L1 / L ≤ 0.6. The first connecting segment 11113 has a first end 11113a and a second end 11113b facing each other along the third direction X, the first wall 111 has a third end 1113 and a fourth end 1114 facing each other along the third direction X, the first end 11113a is close to the third end 1113, the second end 11113b is close to the fourth end 1114, the size of the first wall 111 along the third direction X is L, the minimum distance along the third direction X between the first end 11113a and the third end 1113 is L2, the minimum distance along the third direction X between the second end 11113b and the fourth end 1114 is L3, and L2 / L≦0.3, L3 / L≦0.3, 100mm≦L≦450mm.

[0451] The positive electrode plate 22 includes a positive electrode body region 221 and a positive electrode tab 21a protruding from the positive electrode body region 221, and the negative electrode plate 23 includes a negative electrode body region 231 and a negative electrode tab 21b protruding from the negative electrode body region 231. Along the first direction Z, the positive electrode body region 221 has a fifth end 2211 facing the end cap 12, the negative electrode body region 231 has a sixth end 2311 facing the end cap 12, and the separator member 24 has a seventh end 241 facing the end cap 12, the seventh end 241 being closer to the end cap 12 than the fifth end 2211 and the sixth end 2311. The separator member 24 includes an overhang region 242 that extends beyond the fifth end 2211 and the sixth end 2311 along the first direction Z, and in a projection plane perpendicular to the second direction Y, the overhang region 242 partially overlaps with the orthographic projection of the first region 1111. The first region 1111 includes a first projection 11118 that protrudes from the first inner surface 11121, and in a projection plane perpendicular to the second direction Y, the orthographic projections of the positive electrode body region 221 and the first projection 11118 do not overlap, and in a projection plane perpendicular to the second direction Y, the orthographic projections of the negative electrode body region 231 and the first projection 11118 do not overlap.

[0452] The first wall 111 further includes a first transition region 1117, the first transition region 1117 is connected to one end of the first region 1111 away from the second region 1112 along a first direction Z, the first transition region 1117 is connected to a first connection part 51, the connection position between the first transition region 1117 and the first connection part 51 forms a first connection interface 511, the first connection interface 511 has a first position 5111 that is closest to the first region 1111 along a first direction Z, the first position 5111 is located at one end of the first region 1111 away from the second region 1112 along a first direction Z. The first connecting interface 511 includes a second interface 5113, which extends inclined from the first position 5111 away from the end cap 12, and along the second direction Y, a portion of the first connecting portion 51 is located between the second interface 5113 and the end cap 12, and the second interface 5113 connects the inner surface of the first region 1111 to the first position 5111.

[0453] It should be noted that, as long as they do not conflict, the embodiments and features in this application are combinable with each other.

[0454] The embodiments described above are for illustrative purposes only and are not intended to limit this application. To those skilled in the art, this application is subject to various modifications and changes. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection. [Explanation of Symbols]

[0455] 1-Housing, 11-Case, 111-First Wall, 1111-First Region, 11111-First Part, 11112-Second Part, 11113-First Connecting Segment, 11113a-First End, 11113b-Second End, 11114-Second Connecting Segment, 11115-Third Connecting Segment, 11116-First Transition Segment, 11117-Second Transition Segment, 11118-First Protrusion, 1112-Second Region, 11121-First Inner Surface, 11122-First Outer Surface, 1113-Third End, 1114-Fourth End, 1115-Positioning Restricting Surface 1116 - Position regulating region, 1117 - First transition region, 112 - Second wall, 113 - Corner wall, 1131 - Third region, 1132 - Fourth region, 11321 - Second inner surface, 11322 - Second outer surface, 1133 - First connection end, 1134 - Second connection end, 1135 - Second transition region, 12 - End cap, 121 - Outer surface of end cap, 2 - Electrode assembly, 21 - Tab, 21a - Positive electrode tab, 21b - Negative electrode tab, 22 - Positive electrode plate, 221 - Positive electrode body region, 2211 - Fifth end, 222 - Positive electrode current collector, 223 - Positive electrode active material layer, 2231 - Positive electrode body 2232-Positive electrode thin-walled portion, 224-Insulating layer, 23-Negative electrode plate, 231-Negative electrode main body region, 2311-Sixth end, 232-Negative electrode current collector, 233-Negative electrode active material layer, 2331-Negative electrode main body portion, 2332-Negative electrode thin-walled portion, 24-Separator member, 241-Seventh end, 242-Protruding region, 25-Flat region, 26-Corner region, 27-First surface, 28-Second surface, 3-Electrode terminal, 31-Terminal body, 32-First position regulating portion, 33-Second position regulating portion, 4-Pressure release mechanism, 5-Connection portion, 51-First connection portion, 511-First connection interface, 5111-First position, 511 2-First interface, 5113-Second interface, 5114-Third position, 5115-Fourth position, 52-Second connection, 521-Second connection interface, 5211-Second position, 5212-Third interface, 5213-Fourth interface, 5214-Fifth position, 5215-Sixth position, 6-First insulating member, 7-Second insulating member, 10-Battery cell, 20-Housing, 201-First housing, 202-Second housing, 100-Battery, 200-Controller, 300-Motor, 1000-Vehicle, Z-First direction, Y-Second direction, X-Third direction, U-First interface, V-Second interface.

Claims

1. It is a battery cell, A case having an opening at least at one end along a first direction and including a first wall, An end cap, wherein the opening is sealed and the first wall is welded to the end cap to form a first connection portion, An electrode assembly, at least partially housed within the case, comprising a positive electrode plate and a negative electrode plate, wherein at least a portion of the positive electrode plate and at least a portion of the negative electrode plate are stacked along a second direction, the second direction being parallel to the thickness direction of the first wall, and the first direction comprising an electrode assembly intersecting the second direction, Herein, the first wall includes a first region and a second region arranged along the first direction, the thickness of the first region is greater than the thickness of the second region, and the first region is located between the first connection and the second region, in a battery cell.

2. The battery cell according to claim 1, wherein the electrode assembly has a flat region, and the portion of the positive electrode plate located in the flat region and the portion of the negative electrode plate located in the flat region are stacked and installed along the second direction.

3. The battery cell according to claim 2, wherein the electrode assembly includes an adjacent first surface and a second surface, the first surface being perpendicular to the second direction, the area of ​​the first surface being larger than the area of ​​the second surface, and the first surface and the first wall being positioned opposite each other along the second direction.

4. The battery cell according to claim 3, wherein the first surface is the surface with the largest area among the outer surfaces of the electrode assembly.

5. The electrode assembly has a wound structure, and the electrode assembly further has a corner region, the corner region is located at at least one end along a third direction of the flat region, and the first direction, the second direction and the third direction are not on the same plane and intersect in pairs. The battery cell according to claim 3 or 4, wherein the outer surface of the flat region includes the first surface, and the outer surface of the corner region includes the second surface, and at least a portion of the second surface is an arcuate surface.

6. The battery cell according to claim 3 or 4, wherein the electrode assembly has a laminated structure, the flat region includes a plurality of positive electrode plates and a plurality of negative electrode plates, the plurality of positive electrode plates and the plurality of negative electrode plates are arranged in a laminated manner along the second direction, and the first surface is perpendicular to the second surface.

7. The battery cell according to any one of claims 1 to 6, wherein the first wall is the wall with the largest outer surface area in the case.

8. The battery cell according to any one of claims 1 to 7, wherein the case includes two first walls, the two first walls are positioned opposite each other along the second direction, and the electrode assembly is located between the two first walls.

9. The battery cell according to any one of claims 1 to 8, wherein the first region includes a first portion and a second portion arranged along the first direction, the second portion connects the first portion and the second region, and the thickness of the first portion is greater than the thickness of the second portion.

10. The battery cell according to claim 9, wherein the thickness of the second portion tends to decrease in the direction toward the electrode assembly where the end cap is located.

11. The battery cell according to any one of claims 1 to 10, wherein the size of the first region along the third direction is greater than the size of the first region along the first direction, and the first direction, the second direction and the third direction are not on the same plane and intersect in pairs.

12. The battery cell according to claim 11, wherein the first region includes a first connection segment, the first connection segment passes through a middle cross section of the first wall, the middle cross section is perpendicular to the third direction, and the distance from the middle cross section to both ends of the first wall is equal along the third direction.

13. The battery cell according to claim 12, wherein the first region further includes a second connection segment and a third connection segment, the second connection segment, the first connection segment and the third connection segment are arranged along the third direction, the first connection segment connects the second connection segment and the third connection segment, and the thickness of the first connection segment is greater than the thickness of the second connection segment and the thickness of the third connection segment.

14. The battery cell according to claim 13, wherein the first region further includes a first transition segment, the first connection segment, the first transition segment and the second connection segment are arranged along the third direction, the first transition segment connects the second connection segment and the first connection segment, the thickness of the first transition segment tends to increase along the direction in which the second connection segment is toward the first connection segment, and / or the first region further includes a second transition segment, the first connection segment, the second transition segment and the third connection segment are arranged along the third direction, the second transition segment connects the third connection segment and the first connection segment, the thickness of the second transition segment tends to increase along the direction in which the third connection segment is toward the first connection segment.

15. The size of the first connecting segment along the third direction is L １ The size of the first wall along the third direction is L, and 0.2 ≤ L １ A battery cell according to any one of claims 12 to 14, wherein / L ≤ 0.

6.

16. The first connecting segment has a first end and a second end facing each other along the third direction, the first wall has a third end and a fourth end facing each other along the third direction, the first end is close to the third end, the second end is close to the fourth end, the size of the first wall along the third direction is L, and the minimum distance between the first end and the third end along the third direction is L ２ The minimum distance between the second end and the fourth end along the third direction is L ３ And L ２ / L ≤ 0.3 and / or L ３ A battery cell according to any one of claims 12 to 15, wherein / L ≤ 0.

3.

17. A battery cell according to claim 15 or 16, wherein 100 mm ≤ L ≤ 450 mm.

18. The case includes a corner wall, and the corner wall is connected to both ends of the first wall along the third direction. The battery cell according to any one of claims 11 to 17, wherein at least one end of the first region along the third direction does not contact the corner wall, or both ends of the first region along the third direction extend to the two corner walls, respectively.

19. The electrode assembly further includes a separator member, the separator member being placed between the positive electrode plate and the negative electrode plate. The battery cell according to any one of claims 1 to 18, wherein the positive electrode plate includes a positive electrode body region and a positive electrode tab protruding from the positive electrode body region, the positive electrode body region having a positive electrode active material layer, the negative electrode plate includes a negative electrode body region and a negative electrode tab protruding from the negative electrode body region, the negative electrode body region having a negative electrode active material layer, and along the first direction, the positive electrode body region has a fifth end facing the end cap, the negative electrode body region has a sixth end facing the end cap, the separator member has a seventh end facing the end cap, the seventh end being closer to the end cap than the fifth and sixth ends.

20. The battery cell according to claim 19, wherein the separator member includes overhanging regions that extend beyond the fifth and sixth ends along the first direction, and in a projection plane perpendicular to the second direction, the orthographic projection of the overhanging regions partially overlaps with the orthographic projection of the first region.

21. The second region has a first inner surface facing the internal space of the case, and the first region includes a first projection protruding from the first inner surface. The battery cell according to claim 19 or 20, wherein, in a projection plane perpendicular to the second direction, the orthographic projection of the positive electrode body region and the orthographic projection of the first protrusion do not overlap, and / or, in a projection plane perpendicular to the second direction, the orthographic projection of the negative electrode body region does not overlap with the orthographic projection of the first protrusion.

22. The battery cell according to any one of claims 1 to 21, wherein the negative electrode plate includes a negative electrode current collector and a negative electrode active material layer installed on at least one side of the negative electrode current collector, and the negative electrode active material layer includes a negative electrode active material.

23. The battery cell according to claim 22, wherein the negative electrode active material layer includes a negative electrode body portion and a negative electrode thin portion, the negative electrode body portion and the negative electrode thin portion are arranged along the first direction, and the negative electrode thin portion is installed at one end of the negative electrode body portion adjacent to the end cap along the first direction.

24. The battery cell according to claim 23, wherein, in a projection plane perpendicular to the second direction, the orthographic projection of the negative electrode thin-walled portion and the orthographic projection of the first region are spaced apart along the first direction.

25. The battery cell according to claim 24, wherein, in a projection plane perpendicular to the second direction, the spacing size along the first direction between the orthographic projection of the negative electrode thin-walled portion and the orthographic projection of the first region is 1 mm or more.

26. The one-sided coating weight of the negative electrode active material layer is 90 mg / 1540 mm ２ to 170 mg / 1540 mm ２ and selectively 110 mg / 1540 mm ２ to 150 mg / 1540 mm ２ The battery cell according to any one of claims 22 to 25, which is such.

27. The battery cell according to any one of claims 22 to 26, wherein the porosity of the negative electrode plate is 27% to 40%.

28. The battery cell according to any one of claims 22 to 27, wherein the negative electrode active material comprises a silicon-based material, and the mass content of silicon elements in the silicon-based material in the negative electrode active material is 0.3% to 10%, and selectively 1% to 6%.

29. The battery cell according to claim 28, wherein the silicon-based material comprises at least one of a silicon oxygen compound and a silicon carbon composite.

30. The battery cell according to any one of claims 1 to 29, wherein the positive electrode plate includes a positive electrode current collector and a positive electrode active material layer installed on at least one side of the positive electrode current collector, and the positive electrode active material layer includes a positive electrode active material.

31. The battery cell according to claim 30, wherein the positive electrode active material layer includes a positive electrode body portion and a positive electrode thin portion, the positive electrode body portion and the positive electrode thin portion are arranged along the first direction, and the positive electrode thin portion is provided at one end of the positive electrode body portion adjacent to the end cap along the first direction.

32. The battery cell according to claim 31, wherein, in a projection plane perpendicular to the second direction, the orthographic projection of the positive electrode thin-walled portion and the orthographic projection of the first region are spaced apart along the first direction.

33. The battery cell according to claim 32, wherein, in a projection plane perpendicular to the second direction, the spacing size along the first direction between the orthographic projection of the positive electrode thin-walled portion and the orthographic projection of the first region is 1 mm or more.

34. The coating weight on one side of the positive electrode active material layer is 200 mg / 1540 mm². ２ ~370mg / 1540mm ２ Therefore, selectively 240 mg / 1540 mg ２ ~330mg / 1540mm ２ The battery cell according to any one of claims 30 to 33.

35. The battery cell according to any one of claims 30 to 34, wherein the positive electrode active material is a lithium-containing phosphate.

36. The material of the aforementioned case includes steel, The maximum thickness of the second region is D １ The size of the case along the second direction is D, and 0.001 ≤ D １ A battery cell according to any one of claims 1 to 35, wherein / D ≤ 0.

012.

37. The material of the aforementioned case includes steel, The maximum thickness of the second region is D １ Therefore, 0.08 mm ≤ D １ ≤0.35 mm, and / or the maximum thickness of the first region is D ２ Therefore, 0.1 mm ≤ D ２ A battery cell according to any one of claims 1 to 36, wherein the diameter is ≤0.6 mm.

38. The material of the aforementioned case includes an aluminum alloy. The maximum thickness of the second region is D １ The size of the case along the second direction is D, and 0.005 ≤ D １ A battery cell according to any one of claims 1 to 35, wherein / D ≤ 0.

065.

39. The material of the aforementioned case includes an aluminum alloy. The maximum thickness of the second region is D １ Therefore, 0.4 mm ≤ D １ ≤ 0.8 mm, and / or the maximum thickness of the first region is D ２ Therefore, 0.5 mm ≤ D ２ A battery cell according to any one of claims 1 to 35 and 38, wherein the diameter is ≤ 1.5 mm.

40. The battery cell according to claim 38 or 39, wherein the aluminum alloy contains, by mass percentage, aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%.

41. The battery cell according to any one of claims 1 to 40, wherein the first region is directly connected to the first connection portion.

42. The battery cell according to any one of claims 1 to 41, wherein the first wall further includes a first transition region, the first transition region is connected to one end of the first region away from the second region along the first direction, the first transition region is connected to a first connection portion, the connection position between the first transition region and the first connection portion forms a first connection interface, the first connection interface has a first position closest to the first region along the first direction, and the first position is located at one end of the first region away from the second region along the first direction.

43. The battery cell according to claim 42, wherein at least a portion of the first connection interface extends inclined with respect to the second direction.

44. The battery cell according to claim 43, wherein the first connection interface includes a first interface, the first interface extends inclined toward the end cap from the first position, and at least a portion of the first transition region is located between the first interface and the end cap along the second direction.

45. The battery cell according to claim 44, wherein the first interface is connected to the outer surface of the first region and the first position.

46. The battery cell according to any one of claims 43 to 45, wherein the first connection interface includes a second interface, the second interface extends inclined from the first position toward a direction away from the end cap, and at least a portion of the first transition region is located toward one side of the second interface toward the end cap along the second direction.

47. The battery cell according to claim 46, wherein the second interface is connected to the inner surface of the first region and the first position.

48. The battery cell according to any one of claims 42 to 47, wherein the Vickers hardness of the first transition region is less than the Vickers hardness of the second region, and / or the Vickers hardness of the first transition region is less than the Vickers hardness of the first connection portion.

49. The battery cell according to any one of claims 42 to 48, wherein, along the first direction, the first connection interface is closer to the second region than to the outer surface of the end cap.

50. The battery cell according to any one of claims 1 to 49, wherein the case further includes a second wall and a corner wall, the first wall, the corner wall and the second wall being arranged along the circumferential direction of the opening, and the corner wall connecting the first wall and the second wall.

51. The corner wall is welded to the end cap to form a second connection. The battery cell according to claim 50, wherein the corner wall includes a third region and a fourth region arranged along the first direction, the thickness of the third region being greater than the thickness of the fourth region, and the third region being located between the fourth region and the second connection portion.

52. The battery cell according to claim 51, wherein the third region is directly connected to the first region.

53. The battery cell according to claim 52, wherein the corner wall has a first connecting end and a second connecting end along the circumferential direction of the opening, the first wall is connected to the first connecting end, the second wall is connected to the second connecting end, and the thickness of the third region tends to decrease along the direction from the first connecting end toward the second connecting end.

54. The battery cell according to any one of claims 51 to 53, wherein the third region is directly connected to the second connection portion.

55. The battery cell according to any one of claims 51 to 54, wherein the corner wall further includes a second transition region, the second transition region is connected to one end of the third region away from the fourth region along the first direction, the second transition region is connected to the second connection portion, the connection position between the second transition region and the second connection portion forms a second connection interface, the second connection interface has a second position closest to the third region along the first direction, and the second position is located at one end of the third region away from the fourth region along the first direction.

56. The battery cell according to claim 55, wherein at least a portion of the second connection interface extends inclined with respect to the thickness direction of the corner wall.

57. The battery cell according to claim 56, wherein the second connection interface includes a third interface, the third interface extends inclined toward approaching the end cap from the second position, and at least a portion of the second transition region is located between the third interface and the end cap along the thickness direction of the corner wall.

58. The battery cell according to claim 57, wherein the third interface is connected to the outer surface of the third region and the second position.

59. The battery cell according to any one of claims 56 to 58, wherein the second connection interface includes a fourth interface, the fourth interface extends inclined from the second position toward the end cap, and at least a portion of the second transition region is located toward one side of the fourth interface toward the end cap along the thickness direction of the corner wall.

60. The battery cell according to claim 59, wherein the fourth interface is connected to the inner surface of the third region and the second position.

61. The battery cell according to any one of claims 55 to 60, wherein the Vickers hardness of the second transition region is less than the Vickers hardness of the fourth region, and / or the Vickers hardness of the second transition region is less than the Vickers hardness of the second connection portion.

62. The battery cell according to any one of claims 55 to 61, wherein, along the first direction, the second connection interface is closer to the fourth region than the outer surface of the end cap.

63. The battery cell according to any one of claims 50 to 62, wherein the case includes two first walls and two second walls, the two first walls being positioned opposite each other along the second direction, the two second walls being positioned opposite each other along the third direction, and the first direction, the second direction and the third direction being perpendicular to each other in pairs.

64. The battery cell according to any one of claims 1 to 63, wherein the Vickers hardness of at least a portion of the first region is less than the Vickers hardness of the second region.

65. The battery cell according to any one of claims 1 to 64, wherein, along the first direction, the first wall has a position-restricting surface facing the end cap, the position-restricting surface abuts against the end cap and restricts the end cap from moving in a direction toward the electrode assembly.

66. The battery cell according to claim 65, wherein the first wall further includes a position-regulating region installed on the position-regulating surface, the position-regulating region is installed opposite the end cap along the second direction, and the position-regulating region is welded to the end cap to form the first connection.

67. The battery cell according to any one of claims 1 to 66, wherein the electrode assembly has a laminated structure, and the electrode assembly includes a plurality of positive electrode plates and a plurality of negative electrode plates, and the plurality of positive electrode plates and a plurality of negative electrode plates are arranged in a laminated manner along the second direction.

68. The battery cell according to claim 67, wherein the number of negative electrode plates is greater than the number of positive electrode plates, and one positive electrode plate is installed between two adjacent negative electrode plates.

69. The battery cell according to claim 67 or 68, wherein a negative electrode tab is provided on each of the negative electrode plates and / or a positive electrode tab is provided on each of the positive electrode plates.

70. The battery cell according to any one of claims 67 to 69, wherein, along the third direction, the size of the first region is greater than the size of the positive electrode plate and / or the size of the negative electrode plate, and the first direction, the second direction and the third direction are perpendicular to each other in pairs.

71. The battery cell further includes two electrode terminals, the two electrode terminals being mounted on the end cap, the two electrode terminals having opposite polarities, and both being electrically connected to the electrode assembly. The battery cell according to any one of claims 1 to 70, wherein the end cap is provided with a lead hole, the electrode terminal includes a terminal body, a first position restricting portion and a second position restricting portion, the terminal body is connected to the first position restricting portion and the second position restricting portion, the terminal body is drilled in the lead hole, and along the first direction, the first position restricting portion is located on one side of the end cap away from the electrode assembly, and the second position restricting portion is located on one side of the end cap facing the electrode assembly.

72. A battery comprising a battery cell as described in any one of claims 1 to 71.

73. A power-consuming device comprising a battery cell according to any one of claims 1 to 71, wherein the battery cell is used to provide electrical energy to the power-consuming device.

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