Battery monomer, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device, and belongs to the technical field of batteries. The battery monomer comprises a shell, the shell is provided with a first wall and a second wall which are connected with each other, the first wall is provided with a first groove, the first wall is configured to be capable of cracking along at least part of the first groove to release the internal pressure of the battery monomer when the pressure of the battery monomer is released, and the second wall is located on one side of the first wall along a first direction. The first groove comprises a first groove section, and the first groove section and the second wall are arranged in the first direction. The first wall is further provided with a second groove, the second wall is provided with a first outer surface deviating from the interior of the shell in the first direction, and the projection of the second groove in the thickness direction of the first wall is located between the first outer surface and the projection of the first groove section in the thickness direction of the first wall. And the second groove can absorb excess materials extruded from the first groove section in the forming process of the first groove section, so that the phenomenon that the battery monomer partially protrudes or the planeness of the first wall is reduced is relieved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery and an electrical device. Background Art

[0002] In recent years, new energy vehicles have developed by leaps and bounds. In the field of electric vehicles, power batteries, as the power source of electric vehicles, play an irreplaceable and important role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also growing. Among them, batteries, as core components of new energy vehicles, have high requirements in terms of reliability and service life.

[0003] In battery technology, in order to ensure the safety of battery cells, a pressure relief structure for releasing the internal pressure of the battery cells is generally formed integrally on the outer shell of the battery cells, so that when the internal pressure or temperature of the battery cells reaches a threshold, the pressure relief structure can be actuated to release the internal pressure of the battery cells. However, after the pressure relief structure is processed on the existing battery cells, the overall size consistency of the outer shell of the battery cells is poor, which is not conducive to improving the production quality of the battery cells. Utility Model Content

[0004] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can effectively improve the production quality of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell, the shell having a first wall and a second wall connected to each other, the first wall being provided with a first groove, the first wall being configured to be able to split along at least a portion of the first groove when the battery cell is depressurized to release the internal pressure of the battery cell, the second wall being located on one side of the first wall along a first direction, the first groove comprising a first groove section, the first groove section and the second wall being arranged along the first direction; wherein the first wall is also provided with a second groove, along the first direction, the second wall having a first outer surface facing away from the interior of the shell, and a projection of the second groove in the thickness direction of the first wall being located between the first outer surface and a projection of the first groove section in the thickness direction of the first wall.

[0006] In the above technical solution, the shell has a first wall and a second wall connected to each other, and a first groove is arranged on the first wall, so that the first wall can be cracked along the first groove when the battery cell is depressurized, so as to release the internal pressure of the battery cell, wherein a second groove is also arranged on the first wall, the first groove has a first groove section arranged in the first direction with the second groove, and the second groove is located in the first direction between the first groove section of the first groove and the first outer surface of the second wall, so that the second groove can play a certain separation role between the area of ​​the first wall where the first groove section is arranged and the second wall, on the one hand, the second groove can absorb the extruded excess material of the first groove section during the molding process of the first groove section of the first groove, so as to alleviate the first outer surface of the second wall caused by local extrusion during the processing of the first groove section on the first wall. The phenomenon of local arching or local arching of the first wall can reduce the problems of local size increase of the battery cell in the first direction or reduction of the flatness of the first wall, so as to improve the size consistency of the shell, which is beneficial to improving the production quality of the battery cell. On the other hand, when the battery cell is subjected to internal and external impact forces and deformed, the second groove can also absorb the deformation energy of the battery cell, so that the second groove can play a buffering role between the first groove section and the second wall, so as to play a certain protective role for the area of ​​the first wall where the first groove section is provided, so as to effectively reduce the deformation or damage of the area of ​​the first wall where the first groove is provided when the battery cell is subjected to internal and external impact forces, so as to alleviate the situation of premature actuation of pressure relief of the battery cell during use, which is beneficial to improving the reliability and service life of the battery cell.

[0007] In some embodiments, along the first direction, the minimum distance L1 between the first groove segment and the first outer surface is greater than or equal to 0.11 times the size L2 of the battery cell, and the minimum distance L1 between the first groove segment and the first outer surface is less than or equal to 0.44 times the size L2 of the battery cell.

[0008] In the above technical solution, by setting the ratio of the minimum distance between the first groove segment and the first outer surface to the size of the battery cell in the first direction to 0.11 to 0.44, the second groove arranged between the first groove segment and the first outer surface can better absorb the extruded excess material of the first groove segment during the molding process of the first groove segment of the first groove, thereby facilitating the improvement of the consistency of the size of the battery cell in the first direction and the improvement of the flatness of the first wall.

[0009] In some embodiments, along the first direction, the minimum distance L1 between the first groove segment and the first outer surface is greater than or equal to 0.15 times the size L2 of the battery cell, and the minimum distance L1 between the first groove segment and the first outer surface is less than or equal to 0.4 times the size L2 of the battery cell.

[0010] In the above technical solution, by further setting the ratio of the minimum distance between the first groove segment and the first outer surface to the size of the battery cell in the first direction to 0.15 to 0.4, the effect of the second groove on absorbing the extruded excess material of the first groove segment during the molding process of the first groove segment of the first groove can be further improved, which is beneficial to further improve the flatness of the first wall and to further improve the consistency of the size of the battery cell in the first direction.

[0011] In some embodiments, along the first direction, the minimum distance between the first groove segment and the first outer surface is L1, satisfying 10 mm ≤ L1 ≤ 44 mm.

[0012] In the above technical solution, by setting the minimum distance between the first groove section and the first outer surface in the first direction to be greater than or equal to 10 mm, on the one hand, the size of the area between the first groove section and the first outer surface in the first direction can be increased, so as to reduce the difficulty of setting the second groove between the first groove section and the first outer surface, and the phenomenon that the second groove cannot be set between the first groove section and the first outer surface can be alleviated, which is conducive to reducing the difficulty of manufacturing the battery cell. On the other hand, it can alleviate the phenomenon that the second groove absorbs the residual material extruded during the molding process of the first groove section due to the small spacing between the first groove section and the first outer surface, so as to reduce the phenomenon that the local size of the battery cell increases or the flatness of the first wall is poor due to local extrusion during the processing of the first groove section of the shell, thereby effectively improving the size consistency of the shell. By setting the minimum distance between the first groove section and the first outer surface in the first direction to be less than or equal to 44 mm, the phenomenon that the area between the first groove section and the first outer surface is too large in the first direction, resulting in space waste or excessive processing of the second groove, is reduced, thereby helping to reduce the manufacturing cost of the battery cell.

[0013] In some embodiments, along the first direction, the size of the battery cell is L2, satisfying 25 mm ≤ L2 ≤ 100 mm.

[0014] In the above technical solution, by setting the size of the battery cell in the first direction to be greater than or equal to 25 mm, on the one hand, the number or size of the electrode assemblies contained in the housing can be increased, which is beneficial to improving the energy density of the battery cell, and on the other hand, the problem of difficulty in manufacturing the battery cell due to the small size of the battery cell in the first direction can be alleviated, so as to reduce the difficulty in manufacturing the battery cell, thereby facilitating improving the production efficiency of the battery cell. By setting the size of the battery cell in the first direction to be less than or equal to 100 mm, the problem of difficulty in subsequent assembly of the battery cell due to the large size of the battery cell in the first direction can be alleviated, and the difficulty in manufacturing the battery cell can be reduced.

[0015] In some embodiments, along the thickness direction of the first wall, the minimum residual thickness of the first groove is D1, and the minimum residual thickness of the second groove is D2, satisfying D2>D1.

[0016] In the above technical solution, by setting the minimum residual thickness of the first groove to be smaller than the minimum residual thickness of the second groove, the strength of the area of ​​the first wall where the first groove is set is smaller than the strength of the area of ​​the first wall where the second groove is set, so that the first wall of the shell can preferentially crack along the first groove and release the internal pressure of the battery cell, which helps to alleviate the phenomenon that the first wall cracks from the area where the second groove is set, causing poor pressure relief effect of the battery cell.

[0017] In some embodiments, along the thickness direction of the first wall, the first wall has a first surface and a second surface opposite to each other; wherein the first groove is disposed on the first surface, and the second groove is disposed on the second surface.

[0018] In the above technical solution, the first groove and the second groove are respectively arranged on the first surface and the second surface on both sides of the first wall, so that the first groove and the second groove are respectively located on both sides of the first wall, thereby facilitating the processing of the first groove and the second groove on both sides of the first wall, which is beneficial to reducing the mutual influence of the first groove and the second groove during the processing.

[0019] In some embodiments, along the first direction, the first groove overlaps at least partially with a projection of the second groove.

[0020] In the above technical solution, by arranging the first groove and the second groove to overlap at least part of their projections in the first direction, the second groove and the first groove segment of the first groove have mutually overlapping areas in the first direction, thereby, on the one hand, being able to enhance the absorption effect of the second groove on the excess material squeezed out of the first groove segment during the molding process, so as to reduce the phenomenon that the local size of the battery cell is increased or the flatness of the first wall is poor due to local extrusion of material during the processing of the first groove segment of the first wall of the shell, and on the other hand, being able to enhance the absorption effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deformed, so as to enhance the buffering effect of the second groove between the first groove segment and the second wall, thereby being able to effectively reduce the phenomenon that the area of ​​the first wall where the first groove is arranged is deformed or damaged when the battery cell is subjected to internal and external impact forces.

[0021] In some embodiments, along the thickness direction of the first wall, a groove bottom surface of the second groove is closer to the first surface than a groove bottom surface of the first groove.

[0022] In the above technical solution, the bottom surface of the second groove is closer to the first surface than the bottom surface of the first groove in the thickness direction of the first wall, so that the second groove and the first groove section of the first groove have overlapping areas in the first direction, so that on the one hand, the absorption effect of the second groove on the excess material squeezed out of the first groove section during the molding process can be improved, so as to reduce the phenomenon that the local size of the battery cell is increased or the flatness of the first wall is poor due to local extrusion of material in the process of processing the first groove section of the first wall of the shell; on the other hand, the absorption effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deformed can be improved, so as to enhance the buffering effect of the second groove between the first groove section and the second wall, so as to effectively reduce the deformation or damage of the area of ​​the first wall where the first groove is provided when the battery cell is subjected to internal and external impact forces.

[0023] In some embodiments, along the thickness direction of the first wall, the maximum groove depth of the second groove is H1, and the minimum residual thickness of the first groove is D1, satisfying H1>D1.

[0024] In the above technical solution, by setting the maximum groove depth of the second groove to be greater than the minimum residual thickness of the first groove, the second groove and the first groove segment of the first groove have overlapping areas in the first direction, so that on the one hand, the absorption effect of the second groove on the residual material squeezed out of the first groove segment during the molding process can be improved, so as to reduce the phenomenon that the local size of the battery cell is increased or the flatness of the first wall is poor due to local extrusion of material during the processing of the first groove segment of the first wall of the shell; on the other hand, the absorption effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deformed can be improved, so as to enhance the buffering effect of the second groove between the first groove segment and the second wall, so as to effectively reduce the deformation or damage of the area of ​​the first wall where the first groove is provided when the battery cell is subjected to internal and external impact forces.

[0025] In some embodiments, the first groove is a multi-level groove arranged in sequence along the direction from the first surface to the second surface, and along the thickness direction of the first wall, in two adjacent levels of the grooves, the primary groove away from the first surface is arranged on the groove bottom surface of the primary groove close to the first surface; wherein, the groove arranged on the first surface among the multi-level grooves is a first-level groove, and along the first direction, the second groove at least partially overlaps with the projection of the first-level groove.

[0026] In the above technical solution, by setting the first groove as a multi-stage groove arranged along the thickness direction of the first wall, and setting the second groove and the first-stage groove of the first groove to at least partially overlap in projection in the first direction, the second groove can cover the other multi-stage grooves arranged on the groove bottom surface of the first-stage groove in the first groove section in the first direction, so that on the one hand, the absorption effect of the second groove on the excess material squeezed out of the first groove section during the molding process of the multi-stage groove can be improved, so as to further reduce the phenomenon that the local size of the battery cell is increased or the flatness of the first wall is poor due to local extrusion of material in the process of processing the first groove section of the first wall of the shell, and on the other hand, the absorption effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deformed can be further improved, so as to further enhance the buffering effect of the second groove between the first groove section and the second wall, so as to further reduce the deformation or damage of the battery cell in the area of ​​the first wall where the first groove is provided when the battery cell is subjected to internal and external impact forces.

[0027] In some embodiments, the first groove is a multi-level groove arranged in sequence along the direction from the first surface to the second surface, and along the thickness direction of the first wall, in two adjacent levels of the grooves, the first-level groove away from the first surface is arranged on the groove bottom surface of the first-level groove close to the first surface; wherein, the groove arranged on the first surface among the multi-level grooves is a first-level groove, and along the thickness direction of the first wall, the groove bottom surface of the second groove is flush with the groove bottom surface of the first-level groove or the groove bottom surface of the second groove is closer to the first surface than the groove bottom surface of the first-level groove.

[0028] In the above technical solution, by setting the first groove to be arranged as a multi-stage groove along the thickness direction of the first wall, and setting the groove bottom surface of the second groove to be flush with the groove bottom surface of the first-stage groove or closer to the first surface than the groove bottom surface of the first-stage groove in the thickness direction of the first wall, the second groove can cover other multi-stage grooves arranged on the groove bottom surface of the first-stage groove in the first groove section in the first direction, so that on the one hand, the absorption effect of the second groove on the residual material squeezed out of the first groove section during the molding process of the multi-stage groove can be improved, so as to further reduce the phenomenon that the local size of the battery cell is increased or the flatness of the first wall is poor due to local extrusion of material in the process of processing the first groove section of the first wall of the shell, and on the other hand, the absorption effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deformed can be further improved, so as to further enhance the buffering effect of the second groove between the first groove section and the second wall, so as to further reduce the deformation or damage of the battery cell in the area where the first groove is provided on the first wall when the battery cell is subjected to internal and external impact forces.

[0029] In some embodiments, the first groove is a multi-level groove arranged in sequence from the first surface to the second surface, and along the thickness direction of the first wall, in two adjacent levels of the grooves, the first-level groove away from the first surface is arranged on the groove bottom surface of the first-level groove close to the first surface; wherein, the groove arranged on the first surface among the multi-level grooves is the first-level groove, the maximum groove depth of the second groove is H1, and the minimum residual thickness of the first-level groove is D3, satisfying that H1≥D3.

[0030] In the above technical solution, by setting the first groove as a multi-stage groove arranged along the thickness direction of the first wall, and the maximum groove depth of the second groove is greater than or equal to the minimum residual thickness of the first-stage groove in the multi-stage groove, the second groove can cover the other multi-stage grooves arranged on the groove bottom surface of the first-stage groove in the first groove section in the first direction, so that on the one hand, the absorption effect of the second groove on the residual material squeezed out of the first groove section during the molding process of the multi-stage groove can be improved, so as to further reduce the phenomenon that the local size of the battery cell is increased or the flatness of the first wall is poor due to local extrusion of material in the process of processing the first groove section of the first wall of the shell; on the other hand, the absorption effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deformed can be further improved, so as to further enhance the buffering effect of the second groove between the first groove section and the second wall, so as to further reduce the deformation or damage of the area of ​​the first wall where the first groove is provided when the battery cell is subjected to internal and external impact forces.

[0031] In some embodiments, along the thickness direction of the first wall, the first wall has a first surface and a second surface opposite to each other; wherein the first groove and the second groove are both disposed on the first surface.

[0032] In the above technical solution, the first groove and the second groove are both arranged on the first surface of the first wall so that the first groove and the second groove are located on the same side of the first wall, so that the first groove and the second groove are both processed on the same side of the first wall. On the one hand, it is convenient to realize the mutual spacing and avoidance between the first groove and the second groove during the processing, which is beneficial to reduce the difficulty of processing the first groove and the second groove on the first wall. On the other hand, the processing of the first groove and the second groove can be realized without flipping the first wall, which is beneficial to optimize the production rhythm of the battery cell.

[0033] In some embodiments, the first groove is a multi-level groove arranged in sequence along the direction from the first surface to the second surface, and along the thickness direction of the first wall, in two adjacent levels of the grooves, the first-level groove away from the first surface is arranged on the groove bottom surface of the first-level groove close to the first surface; wherein, the groove arranged on the first surface among the multi-level grooves is a first-level groove, and along the thickness direction of the first wall, the groove bottom surface of the first-level groove is closer to the first surface than the groove bottom surface of the second groove.

[0034] In the above technical solution, the bottom surface of the first groove is closer to the first surface in the thickness direction of the first wall than the bottom surface of the second groove, so that the second groove is a structure of the first groove covering the first groove section in the first direction. Therefore, on the one hand, the absorption effect of the second groove on the excess material squeezed out of the first groove section in the process of forming the multi-stage groove can be improved, so as to reduce the local size increase of the battery cell or the poor flatness of the first wall caused by local extrusion of material in the process of processing the first groove section of the first wall of the shell. On the other hand, the absorption effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deformed can be improved, so as to enhance the buffering effect of the second groove between the first groove section and the second wall, so as to effectively reduce the deformation or damage of the area of ​​the first wall where the first groove is provided when the battery cell is subjected to internal and external impact forces.

[0035] In some embodiments, the first groove is a multi-level groove arranged in sequence along the direction from the first surface to the second surface, and along the thickness direction of the first wall, in two adjacent levels of the grooves, the primary groove away from the first surface is arranged on the groove bottom surface of the primary groove close to the first surface; wherein, the groove arranged on the first surface among the multi-level grooves is a first-level groove, and along the thickness direction of the first wall, the maximum groove depth of the second groove is H1, and the maximum groove depth of the first-level groove is H2, satisfying H1>H2.

[0036] In the above technical solution, by setting the maximum groove depth of the second groove to be greater than the maximum groove depth of the first groove in the multi-stage groove of the first groove, the second groove is made to be a structure of the first groove covering the first groove section in the first direction, thereby, on the one hand, being able to enhance the absorption effect of the second groove on the excess material squeezed out of the first groove section in the process of forming the multi-stage groove, so as to reduce the phenomenon that the local size of the battery cell is increased or the flatness of the first wall is poor due to local extrusion of material in the process of processing the first groove section of the shell, and on the other hand, being able to enhance the absorption effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deformed, so as to enhance the buffering effect of the second groove between the first groove section and the second wall, thereby being able to effectively reduce the phenomenon that the area of ​​the first wall where the first groove is provided is deformed or damaged when the battery cell is subjected to internal and external impact forces.

[0037] In some embodiments, the first surface is a surface of a side of the first wall facing away from the interior of the housing.

[0038] In the above technical solution, by setting the first surface of the first wall as the surface of the first wall on the side away from the interior of the shell, the first groove is set on the side of the first wall away from the interior of the shell, thereby facilitating the formation of the first groove on the first wall of the shell, which is beneficial to reducing the difficulty of processing the first groove and improving the production efficiency of the battery cell.

[0039] In some embodiments, along the first direction, the shell has two second walls arranged opposite to each other in the first direction, and the two second walls are respectively connected to two sides of the first wall; wherein, along the first direction, the first groove section is located between the two second walls, and the second groove is provided between the first groove section and the first outer surfaces of the two second walls.

[0040] In the above technical solution, the shell has two second walls located on both sides of the first wall in the first direction, and second grooves are arranged between the two second walls and the first groove section, so that the first groove section is located between the two second grooves in the first direction. On the one hand, the two second grooves can absorb the excess material squeezed out from both sides during the molding process of the first groove section, so as to further reduce the phenomenon that the first wall of the shell causes the local size of the battery cell to increase or the flatness of the first wall to be poor due to local extrusion during the processing of the first groove section. On the other hand, the two second grooves can protect from both sides of the first groove section, so as to absorb the deformation energy transmitted from both sides of the first groove section when the battery cell is subjected to internal and external impact forces, thereby further reducing the deformation or damage of the area of ​​the first wall where the first groove is arranged when the battery cell is subjected to internal and external impact forces.

[0041] In some embodiments, the first wall is a rectangular structure, and a width direction of the first wall and a thickness direction of the second wall are both parallel to the first direction.

[0042] In the above technical solution, the first wall is a rectangular structure, so that the outer shell of the battery cell is a rectangular structure, and the width direction of the first wall and the thickness direction of the second wall both extend along the first direction, so that the second groove is located on one side of the first groove section in the width direction of the first wall, so that the second groove is set on the side that is extremely easy to deform during the forming process of the first groove section or the side that is extremely easy to be affected by impact force, which is beneficial to enhance the buffering and protection effect of the second groove on the first groove section.

[0043] In some embodiments, along the thickness direction of the first wall, two ends of the projection of the second groove in its extension direction respectively extend beyond two ends of the projection of the first groove segment.

[0044] In the above technical solution, along the thickness direction of the first wall, by setting the projection of the second groove in its extension direction to extend respectively beyond the two ends of the projection of the first groove segment, the second groove is a structure in which the two ends in its extension direction respectively exceed the two ends of the first groove segment, thereby improving the separation effect of the second groove between the first groove segment and the second wall, so as to improve the absorption effect of the second groove on the excess material extruded during the molding process of the first groove segment, and can improve the blocking effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces.

[0045] In some embodiments, the second groove extends along a second direction, and along the second direction, two ends of the second groove extend out of two ends of the first groove segment respectively, and the first direction, the second direction and the thickness direction of the first wall are perpendicular to each other.

[0046] In the above technical solution, by setting the second groove as a structure extending along the second direction, it is beneficial to improve the regularity of the shape of the second groove, thereby reducing the difficulty of processing the second groove, and it is convenient to set the second groove as a structure in which both ends in the second direction respectively exceed the two ends of the first groove section, so as to reduce the difficulty of manufacturing the battery cell, which is beneficial to improve the production efficiency of the battery cell.

[0047] In some embodiments, the first groove further includes a second groove section, the first groove section is connected to the second groove section, the first groove section and the second groove section jointly define a predetermined pressure relief area, and the predetermined pressure relief area is configured to be opened when the first wall is cracked along at least a portion of the first groove to release the internal pressure of the battery cell.

[0048] In the above technical solution, the first groove also has a second groove section, and the second groove section and the first groove section are interconnected, so that the first groove section and the second groove section jointly define a predetermined pressure relief area. On the one hand, the pressure relief area of ​​the battery cell can be increased to increase the pressure relief rate of the battery cell. On the other hand, the position where the first groove section and the second groove section are interconnected is weaker, which is easier to crack and open the predetermined pressure relief area to release the internal pressure of the battery cell.

[0049] In some embodiments, the first groove further includes a second groove segment and a third groove segment, the second groove segment and the third groove segment are arranged opposite to each other along a second direction, and the second direction is perpendicular to the first direction; wherein, the first groove segment connects the second groove segment and the third groove segment, and the first groove segment, the second groove segment and the third groove segment jointly define a predetermined pressure relief area, and the predetermined pressure relief area is configured to be opened and flipped around the second groove when the first wall is cracked along the first groove to release the internal pressure of the battery cell.

[0050] In the above technical solution, the first groove also includes a third groove section arranged opposite to the second groove section on the second side, and the first groove section connects the second groove section and the third groove section, so that the first wall can be split along the first groove section, the second groove section and the third groove section when the battery cell is depressurized, so as to open the predetermined pressure relief area to release the internal pressure of the battery cell. The first groove with such a structure makes the intersection position of the first groove section and the second groove section and the connection position of the first groove section and the third groove section weaker, and is easier to split and open the predetermined pressure relief area for pressure relief, and can further improve the pressure relief area and pressure relief rate of the battery cell. In addition, since the second groove and the first groove section are arranged along the first direction, the predetermined pressure relief area defined by the first groove section, the second groove section and the third groove section can also be turned around the second groove as the axis when it is opened, which is conducive to improving the effect and degree of opening of the predetermined pressure relief area, so as to further improve the pressure relief effect of the battery cell.

[0051] In some embodiments, the connection position between the second slot segment and the first slot segment deviates from the two ends of the second slot segment, and the connection position between the third slot segment and the first slot segment deviates from the two ends of the third slot segment, so that the predetermined pressure relief area is formed on both sides of the first slot segment.

[0052] In the above technical solution, by setting the connection position between the second slot segment and the first slot segment to be located between the two ends of the second slot segment, and setting the connection position between the third slot segment and the first slot segment to be located between the two ends of the third slot segment, so that the first slot segment, the second slot segment and the third slot segment form a structure similar to an "H" shape, both sides of the first slot segment of the first groove can form a predetermined pressure relief area, and the two predetermined pressure relief areas can be opened in a split manner for pressure relief when the battery cell is depressurized, which is beneficial to further increase the pressure relief effect of the battery cell and can effectively improve the pressure relief rate of the battery cell.

[0053] In some embodiments, the first slot segment, the second slot segment, and the third slot segment all extend along a straight line trajectory, and the second slot segment and the third slot segment are both perpendicular to the first slot segment.

[0054] In the above technical solution, by setting the second groove section and the third groove section to be perpendicular to the first groove section, so that the extension direction of the first groove section is the arrangement direction of the second groove section and the third groove section, on the one hand, the regularity of the shape of the first groove can be improved, which is conducive to reducing the processing difficulty of the first groove, so as to reduce the manufacturing cost of the battery cell; on the other hand, it is convenient for the two predetermined pressure relief areas on the first wall located on both sides of the first groove section to relieve pressure in opposite directions when the battery cell is depressurized.

[0055] In some embodiments, the first slot segment, the second slot segment, and the third slot segment all extend along an arc trajectory.

[0056] In the above technical solution, by setting the first groove section, the second groove section and the third groove section as structures extending along an arc trajectory, it is beneficial to improve the arc degree of the connection position of the first groove section and the second groove section, and the arc degree of the connection position of the first groove section and the third groove section can be improved. On the one hand, it can reduce the difficulty of processing the first groove, and on the other hand, it can facilitate the first wall to open the predetermined pressure relief area after cracking along the first groove section, the second groove section and the third groove section to release the internal pressure of the battery cell.

[0057] In some embodiments, the first groove further includes a fourth groove segment, the fourth groove segment is located between the second groove segment and the third groove segment, and the fourth groove segment is connected to the first groove segment.

[0058] In the above technical solution, the first groove is also provided with a fourth groove section located between the second groove section and the third groove section, and the fourth groove section is interconnected with the first groove section, so that the stress at the position where the fourth groove section and the first groove section are interconnected is more concentrated and easier to rupture, so that the first wall can rupture along the first groove section from the position where the first groove section and the fourth groove section intersect, and rupture along the second groove section and the third groove section after the first groove section ruptures, so as to achieve rapid pressure relief of the battery cell.

[0059] In some embodiments, along the thickness direction of the first wall, a projection of the first groove does not overlap with a projection of the second groove.

[0060] In the above technical solution, the first groove and the second groove are arranged to have non-overlapping projections in the thickness direction of the first wall, so that the first groove and the second groove do not contact each other. On the one hand, the mutual influence between the first groove and the second groove during the processing can be reduced; on the other hand, the phenomenon of the first wall cracking along the second groove when the first wall cracks along the first groove to release pressure can be reduced, and the stress influence between the area of ​​the first wall where the first groove is set and the area of ​​the first wall where the second groove is set can be reduced.

[0061] In some embodiments, along the first direction, the second groove is spaced apart from the first groove.

[0062] In the above technical solution, the second groove is arranged to be spaced apart from the second groove section and the third groove section of the first groove in the first direction, so that the predetermined pressure relief area defined by the first groove section, the second groove section and the third groove section can be flipped around the area of ​​the first wall where the second groove is arranged when opened, and the flipping angle of the predetermined pressure relief area after being opened can be increased, so as to increase the pressure relief area of ​​the battery cell.

[0063] In some embodiments, the outer shell includes a shell and an end cover; the interior of the shell forms a accommodating cavity with an opening, and the accommodating cavity is used to accommodate the electrode assembly; the end cover closes the opening; wherein the shell includes the first wall; or, the end cover is the first wall.

[0064] In the above technical solution, by setting the first wall of the shell as a wall of the shell, the battery cell adopting this structure can make the area of ​​the shell provided with the first groove and the second groove away from the end cover, so as to effectively alleviate the phenomenon that the stress generated by the connection between the end cover and the shell acts on the area provided with the first groove and the second groove, so as to reduce the impact on the area of ​​the first wall provided with the first groove and the second groove, thereby facilitating the reduction of the risk of cracking or structural strength reduction in the area of ​​the first wall provided with the first groove and the second groove under the pulling action of stress, so as to improve the service life and reliability of the battery cell. By setting the first wall of the shell as the end cover of the shell for closing the opening, the battery cell adopting this structure is convenient for setting the first groove and the second groove on the end cover, which is conducive to reducing the manufacturing difficulty of the battery cell and improving the production efficiency of the battery cell.

[0065] In some embodiments, the outer shell includes a shell and two end covers; a accommodating cavity is formed inside the shell, and the accommodating cavity is used to accommodate the electrode assembly, and openings are formed at both opposite ends of the shell, and both openings are connected to the accommodating cavity; the two end covers respectively close the two openings; wherein, one of the two end covers is the first wall; or the shell includes the first wall.

[0066] In the above technical solution, the shell of the shell is provided with openings at both opposite ends, and the two end covers respectively close the two openings, and the first wall is one of the two end covers. The battery cell using this structure is convenient for assembling the battery cell from both ends of the shell, which is conducive to reducing the manufacturing difficulty and assembly difficulty of the battery cell, and is convenient for setting the first groove and the second groove on the end cover, which is conducive to reducing the manufacturing difficulty of the battery cell, so as to improve the production efficiency of the battery cell. By setting the first wall of the shell as a wall of the shell, the battery cell using this structure can make the area of ​​the shell provided with the first groove and the second groove away from the end cover, so as to effectively alleviate the phenomenon that the stress generated by the connection between the end cover and the shell acts on the area provided with the first groove and the second groove, so as to reduce the influence on the area of ​​the first wall provided with the first groove and the second groove, and further help to reduce the risk of cracking or structural strength reduction of the area of ​​the first wall provided with the first groove and the second groove under the pulling action of stress, so as to improve the service life and reliability of the battery cell.

[0067] In a second aspect, an embodiment of the present application further provides a battery, comprising the above-mentioned battery cell.

[0068] In a third aspect, an embodiment of the present application further provides an electrical device, comprising the above-mentioned battery cell, wherein the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0070] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0071] Figure 2 An exploded view of the structure of a battery provided in some embodiments of the present application;

[0072] Figure 3 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application;

[0073] Figure 4 An exploded view of the structure of a battery cell provided in some embodiments of the present application;

[0074] Figure 5 A bottom view of a housing of a battery cell provided in some embodiments of the present application;

[0075] Figure 6 A partial cross-sectional view of a housing of a battery cell provided in some embodiments of the present application;

[0076] Figure 7 for Figure 6 A partial enlarged view of the housing at A shown;

[0077] Figure 8 A bottom view of a housing of a battery cell provided in some other embodiments of the present application;

[0078] Fig. 9 A partial cross-sectional view of a housing of a battery cell provided in some other embodiments of the present application;

[0079] Fig.10 A bottom view of a housing of a battery cell provided in some further embodiments of the present application;

[0080] Fig.11 A bottom view of a housing of a battery cell provided in some other embodiments of the present application;

[0081] Fig.12A bottom view of a housing of a battery cell provided for still further embodiments of the present application.

[0082] Icon: 1000-vehicle; 100-battery; 10-box; 11-first box body; 12-second box body; 20-battery cell; 21-housing; 211-first wall; 2111-first surface; 2112-second surface; 2113-predetermined pressure relief area; 212-second wall; 2121-first outer surface; 213-first groove; 213a-first groove section; 213b-second groove section; 213c -third slot section; 213d-fourth slot section; 2131-first-stage slot; 2132-second-stage slot; 2133-third-stage slot; 214-second groove; 215-shell; 2151-opening; 216-end cover; 22-electrode assembly; 221-ear; 23-electrode terminal; 24-current collecting member; 200-controller; 300-motor; X-first direction; Y-second direction; Z-thickness direction of the first wall. DETAILED DESCRIPTION

[0083] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0084] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0085] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0086] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0087] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0088] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0089] The term "plurality" used in the present application refers to two or more (including two).

[0090] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0091] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., which is not limited in the embodiments of the present application.

[0092] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting, while allowing active ions to pass through.

[0093] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0094] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0095] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0096] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05O2) and its modified compounds, etc.

[0097] In some embodiments, the positive electrode may be a foamed metal. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, etc. When the foamed metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foamed metal, but of course, the positive electrode active material may also be provided. As an example, a lithium source material, potassium metal or sodium metal may also be filled or / and deposited in the foamed metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[0098] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0099] As an example, the negative electrode current collector may be a metal foil, a foamed metal or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, nickel or titanium, etc. may be used. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, etc. The composite current collector may include a polymer material base and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0100] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0101] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0102] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells known in the art. As an 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, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide 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 oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0103] 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.

[0104] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0105] In some embodiments, the separator is a separator membrane. There may be many types of separator membranes, and any known porous separator membrane with good chemical stability and mechanical stability may be selected.

[0106] As an example, the material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or may be attached to the surface of the positive and negative electrodes.

[0107] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transmit ions and isolate the positive and negative electrodes.

[0108] In some embodiments, the battery cell further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The electrolyte can be liquid, gel or solid. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0109] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0110] 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, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether 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.

[0111] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0112] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0113] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, and the like.

[0114] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0115] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0116] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0117] In some embodiments, the electrode assembly is a laminate structure.

[0118] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be provided respectively, and the plurality of positive electrode sheets and the plurality of negative electrode sheets may be alternately stacked.

[0119] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0120] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded sections that are stacked.

[0121] As an example, a plurality of separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0122] As an example, the separator may be disposed continuously, and may be disposed between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0123] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0124] In some embodiments, the electrode assembly is provided with tabs, which can lead current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0125] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0126] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes but is not limited to a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery, etc.

[0127] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0128] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0129] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are accommodated in the case.

[0130] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0131] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0132] Batteries have outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient. They are an important part of the development of new energy today. The development of battery technology must consider many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the safety of the battery also needs to be considered.

[0133] In battery technology, for general battery cells, in order to ensure the safety of battery cells, a pressure relief structure is usually set on the battery cell to release the internal pressure of the battery cell through the pressure relief structure, thereby effectively improving the safety of battery cells. In related technologies, the pressure relief structure is usually formed on the outer shell by an integrated molding process. For example, a notched groove is stamped on the outer shell so that when the internal pressure or temperature of the battery cell reaches a threshold, the pressure relief structure can be actuated and opened to release the internal pressure of the battery cell. However, in the process of stamping the notched groove on the outer shell, the remaining material of the notched groove will flow to both sides and be discharged, so that the outer shell is prone to material extrusion, resulting in poor flatness of the outer shell or local size increase, resulting in poor dimensional consistency of the outer shell, which is not conducive to improving the production quality of battery cells. In addition, during the use of battery cells, the outer shell of the battery cells will be deformed when subjected to internal and external impact forces, such as internal impact caused by the expansion of the electrode assembly or external impact caused by external collision, so that the deformation energy of the outer shell will directly act on the pressure relief structure, so that the pressure relief structure is at risk of deformation or damage, which in turn leads to poor stability in use of the pressure relief structure, and easily causes the pressure relief structure to prematurely actuate the pressure relief during use, which is not conducive to improving the service life and reliability of the battery cells.

[0134] Based on the above considerations, in order to solve the problem of low production quality of battery cells, an embodiment of the present application provides a battery cell, the battery cell includes a shell, the shell has a first wall and a second wall connected to each other, the first wall is provided with a first groove, the first wall is configured to be able to crack along at least part of the first groove when the battery cell is depressurized to release the internal pressure of the battery cell, the second wall is located on one side of the first wall along the first direction, the first groove includes a first groove section, the first groove section and the second wall are arranged along the first direction. The first wall is also provided with a second groove, along the first direction, the second wall has a first outer surface facing away from the inside of the shell, and the projection of the second groove in the thickness direction of the first wall is located between the first outer surface and the projection of the first groove section in the thickness direction of the first wall, and the first direction is perpendicular to the thickness direction of the first wall.

[0135] In a battery cell of this structure, the shell has a first wall and a second wall that are connected to each other, and a first groove is provided on the first wall, so that the first wall can be cracked along the first groove when the battery cell is depressurized, so as to release the internal pressure of the battery cell, wherein a second groove is also provided on the first wall, and the first groove has a first groove section arranged in the first direction with the second groove, and the second groove is located in the first direction between the first groove section of the first groove and the first outer surface of the second wall, so that the second groove can play a certain separation role between the area of ​​the first wall where the first groove section is provided and the second wall, on the one hand, the second groove can absorb the extruded excess material of the first groove section during the molding process of the first groove section of the first groove, so as to alleviate the first outer surface of the second wall caused by local extrusion during the processing of the first groove section on the first wall. The surface or the first wall has a local arch phenomenon, which can reduce the problem of local size increase of the battery cell in the first direction or reduction in the flatness of the first wall, so as to improve the size consistency of the shell, which is beneficial to improving the production quality of the battery cell. On the other hand, when the battery cell is subjected to internal and external impact forces and deformed, the second groove can also absorb the deformation energy of the battery cell, so that the second groove can play a buffering role between the first groove section and the second wall, so as to play a certain protective role for the area of ​​the first wall where the first groove section is provided, thereby effectively reducing the deformation or damage of the area of ​​the first wall where the first groove is provided when the battery cell is subjected to internal and external impact forces, so as to alleviate the situation of premature actuation of pressure relief of the battery cell during use, which is beneficial to improving the reliability and service life of the battery cell.

[0136] The battery cells disclosed in the embodiments of the present application can be used, but not limited to, in electrical devices such as vehicles, ships or aircraft. A power supply system having the battery cells and batteries disclosed in the present application can be used to form the electrical device, which is helpful to alleviate the problem of poor dimensional consistency of the battery cell shell, so as to improve the production quality of the battery cell.

[0137] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0138] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0139] Please refer to Figure 1 , Figure 1A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom of the vehicle 1000, or at the head of the vehicle 1000, or at the tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source or a power source for the vehicle 1000, etc. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for the starting, navigation and working power requirements of the vehicle 1000 during driving.

[0140] In some embodiments of the present application, the battery 100 can not only serve as an operating power source or a use power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0141] Please refer to Figure 2 and Figure 3 , Figure 2 The structure explosion diagram of the battery 100 provided in some embodiments of the present application is shown in FIG. Figure 3 The schematic diagram of the structure of the battery cell 20 provided in some embodiments of the present application is as follows. The battery 100 comprises a box body 10 and a battery cell 20 , and the battery cell 20 is used to be accommodated in the box body 10 .

[0142] The box body 10 is used to provide an assembly space for the battery cell 20, and the box body 10 can adopt a variety of structures. In some embodiments, the box body 10 may include a first box body 11 and a second box body 12, the first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cell 20. The second box body 12 may be a hollow structure with one end open, and the first box body 11 may be a plate-like structure, and the first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define an assembly space; the first box body 11 and the second box body 12 may also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0143] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid or a cube. Figure 2 In the embodiment, the box body 10 is in the shape of a rectangular parallelepiped.

[0144] In the battery 100, the battery cell 20 disposed in the box 10 may be one or more. When there are more than one battery cell 20 disposed in the box 10, the multiple battery cells 20 may be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in mixed connection, and then the whole formed by the multiple battery cells 20 may be accommodated in the box 10; of course, the battery 100 may also be a battery module formed by connecting multiple battery cells 20 in series, in parallel, or in mixed connection, and then the multiple battery modules may be connected in series, in parallel, or in mixed connection to form a whole, and then the whole may be accommodated in the box 10.

[0145] In some embodiments, the battery 100 may further include other structures. For example, the battery 100 may further include a busbar component, which is used to connect the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0146] Each battery cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be in a rectangular parallelepiped, a cylinder, a prism or other shapes. For example, Figure 3 In the figure, the battery cell 20 is a rectangular parallelepiped structure.

[0147] According to some embodiments of the present application, referring to Figure 3 , and please refer to Figure 4 , Figure 5 and Figure 6 , Figure 4 This is an exploded view of the structure of the battery cell 20 provided in some embodiments of the present application. Figure 5 A bottom view of a housing 21 of a battery cell 20 provided in some embodiments of the present application, Figure 6A partial cross-sectional view of a housing 21 of a battery cell 20 provided in some embodiments of the present application. The present application provides a battery cell 20, the battery cell 20 includes a housing 21, the housing 21 has a first wall 211 and a second wall 212 connected to each other, the first wall 211 is provided with a first groove 213, the first wall 211 is configured to be able to be split along at least part of the first groove 213 when the battery cell 20 is depressurized to release the internal pressure of the battery cell 20, the second wall 212 is located on one side of the first wall 211 along the first direction X, the first groove 213 includes a first groove section 213a, and the first groove section 213a and the second wall 212 are arranged along the first direction X. The first wall 211 is also provided with a second groove 214. Along the first direction X, the second wall 212 has a first outer surface 2121 facing away from the interior of the shell 21, and the projection of the second groove 214 in the thickness direction Z of the first wall is located between the first outer surface 2121 and the first groove section 213a in the thickness direction Z of the first wall. The first direction X is perpendicular to the thickness direction Z of the first wall.

[0148] The first groove 213 serves to release pressure, and is used to enable the first wall 211 to rupture along the first groove 213 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, so as to release the pressure inside the battery cell 20 .

[0149] Optionally, the first groove 213 may be disposed on a side of the first wall 211 facing the interior of the housing 21, or may be disposed on a side of the first wall 211 facing away from the interior of the housing 21. Figure 5 and Figure 6 In the embodiment, the first groove 213 is disposed on a side of the first wall 211 facing away from the interior of the housing 21 , that is, the first groove 213 is disposed on a surface of the first wall 211 facing away from the interior of the housing 21 .

[0150] Optionally, the second groove 214 may be disposed on the same side of the first wall 211 as the first groove 213, or may be disposed on both sides of the first wall 211. Figure 5 and Figure 6 In the embodiment, the second groove 214 and the first groove 213 are respectively arranged on both sides of the first wall 211 , the first groove 213 is arranged on the side of the first wall 211 away from the inside of the shell 21 , and the second groove 214 is arranged on the side of the first wall 211 facing the inside of the shell 21 .

[0151] Exemplarily, the first groove 213 and the second groove 214 are both formed by a stamping process.

[0152] The housing 21 has a first wall 211 and a second wall 212 connected to each other, that is, the first wall 211 and the second wall 212 are two adjacent and interconnected walls of the housing 21. Figure 4 , Figure 5 and Figure 6 In the embodiment, the housing 21 is a rectangular parallelepiped structure, the first wall 211 and the second wall 212 are two perpendicular walls, and correspondingly, the thickness direction of the second wall 212 is the first direction X, and the first outer surface 2121 is a planar structure. It should be noted that, in some embodiments, if the housing 21 is a cylindrical structure, the first wall 211 is a wall at one end of the housing 21 in the axial direction, and the second wall 212 is a circular side wall arranged around the first wall 211, and correspondingly, the first direction X is the radial direction of the first wall 211, and the first outer surface 2121 is an arc surface.

[0153] For example, in Figure 4 , Figure 5 and Figure 6 In the figure, the housing 21 is a rectangular parallelepiped structure, and correspondingly, the first wall 211 is a rectangular structure. The first direction X is the width direction of the first wall 211 and also the thickness direction of the second wall 212. The first wall 211 and the second wall 212 are perpendicular to each other.

[0154] The first groove 213 includes a first groove section 213a, and the first groove section 213a and the second wall 212 are arranged along the first direction X, that is, the first groove 213 has a first groove section 213a arranged in the first direction X with the second wall 212, that is, the first groove section 213a is a straight groove section or an arc groove section extending roughly along the second direction Y perpendicular to the first direction X.

[0155] The second groove 214 is located between the first outer surface 2121 and the first groove section 213a in the thickness direction Z of the first wall, that is, in the first direction X, the first groove section 213a, the second groove 214 and the first outer surface 2121 of the second wall 212 are arranged in sequence along the first direction X, so that the first groove section 213a of the first groove 213 and the first outer surface 2121 of the second wall 212 are respectively located on both sides of the second groove 214 in the first direction X.

[0156] The first outer surface 2121 is a surface of the second wall 212 facing away from the interior of the housing 21 in the first direction X.

[0157] For example, in Figure 5 In the embodiment, the second groove 214 and the first groove section 213a of the first groove 213 are both linear structures extending along the second direction Y, and the first direction X, the second direction Y and the thickness direction Z of the first wall are perpendicular to each other.

[0158] In some embodiments, see Figure 4As shown, the battery cell 20 may further include an electrode assembly 22, which is accommodated in the outer shell 21. The electrode assembly 22 is a component in the battery cell 20 where an electrochemical reaction occurs. The structure of the electrode assembly 22 may be various. For example, the electrode assembly 22 may be a wound structure formed by winding a positive electrode sheet, an isolation member, and a negative electrode sheet, or may be a stacked structure formed by stacking a positive electrode sheet, an isolation member, and a negative electrode sheet.

[0159] Exemplarily, the isolation member is an isolation membrane, and a main material of the isolation membrane may be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0160] Optionally, the number of electrode assemblies 22 contained in the housing 21 may be one or more. Figure 4 In the embodiment, two electrode assemblies 22 are disposed in the housing 21 of the battery cell 20, and the two electrode assemblies 22 are stacked along the thickness direction thereof, that is, the two electrode assemblies 22 are stacked along the thickness direction of the battery cell 20. Of course, in other embodiments, the number of electrode assemblies 22 accommodated in the housing 21 may be one, three, four, five, six, seven or eight.

[0161] The housing 21 can also be used to contain electrolytes, such as electrolytes. The housing 21 can be in various structural forms, such as a cylinder, a cuboid, or a prism structure. Similarly, the housing 21 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy.

[0162] In some embodiments, the housing 21 may include a shell 215 and an end cap 216, wherein a receiving cavity is formed inside the shell 215, the receiving cavity is used to receive the electrode assembly 22, and the receiving cavity has an opening 2151, that is, the shell 215 is a hollow structure with an opening 2151 at one end, and the end cap 216 covers the opening 2151 of the shell 215 and forms a sealed connection to form an enclosed space for receiving the electrode assembly 22 and the electrolyte.

[0163] Optionally, the shell 215 includes an integrally formed bottom wall and side walls, the side wall is arranged around the bottom wall, one end of the side wall is connected to the bottom wall, and the other end is enclosed to form an opening 2151, and the end cover 216 covers the opening 2151 and is arranged opposite to the bottom wall.

[0164] It should be noted that the first wall 211 provided with the first groove 213 may be the end cover 216 of the housing 21, or may be a wall of the shell 215 of the housing 21. Figure 3 and Figure 4In the embodiment, the first wall 211 is a bottom wall of the housing 215 disposed opposite to the end cover 216 in the thickness direction Z of the first wall, and correspondingly, the second wall 212 is one of the side walls of the housing 215. Of course, the structure of the battery cell 20 is not limited thereto, and in other embodiments, the first wall 211 may also be the end cover 216, or the first wall 211 may also be a side wall of the housing 215 and the end cover 216 that are adjacent to and connected to each other.

[0165] When assembling the battery cell 20 , the electrode assembly 22 may be placed into the housing 215 first, and the housing 215 may be filled with electrolyte. The end cap 216 may then be closed onto the opening 2151 of the housing 215 to complete the assembly of the battery cell 20 .

[0166] The shell 215 can be in various shapes, such as a cylinder, a cuboid, or a prism structure. The shape of the shell 215 can be determined according to the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 is a cylindrical structure, a shell 215 with a cylindrical structure can be selected; if the electrode assembly 22 is a cuboid structure, a shell 215 with a cuboid structure can be selected. Of course, the structure of the end cap 216 can also be various, such as the end cap 216 being a plate-like structure or a hollow structure with one end open. For example, in Figure 4 In the embodiment, the shell 215 is a rectangular parallelepiped structure, and the end cover 216 is a rectangular plate structure.

[0167] Of course, it is understandable that the outer shell 21 is not limited to the above structure, and the outer shell 21 may also be other structures. For example, the outer shell 21 may include a shell body 215 and two end caps 216. The shell body 215 is a hollow structure with openings 2151 on opposite sides. One end cap 216 corresponds to an opening 2151 of the shell body 215 and forms a sealed connection to form an enclosed space for accommodating the electrode assembly 22 and the electrolyte. That is, the shell body 215 is formed with openings 2151 on opposite sides, and the two end caps 216 are respectively covered on the two sides of the shell body 215 to close the corresponding openings 2151. Correspondingly, the first wall 211 is one of the two end caps 216.

[0168] In some embodiments, see Figure 4 As shown, the battery cell 20 may further include an electrode terminal 23 , which is insulated and mounted on the housing 21 , and is electrically connected to the electrode assembly 22 to output or input electrical energy of the battery cell 20 .

[0169] It should be noted that the electrode terminal 23 is insulated and mounted on the housing 21 , that is, no electrical connection is formed between the electrode terminal 23 and the housing 21 .

[0170] Among them, Figure 3 and Figure 4In the embodiment, the battery cell 20 includes two electrode terminals 23, which are arranged on the first wall 211 at intervals along the second direction Y. Correspondingly, each electrode assembly 22 has two pole ears 221, and the polarities of the two pole ears 221 are opposite. The two electrode terminals 23 are electrically connected to the two pole ears 221 of the electrode assembly 22, respectively, so as to realize the input or output of the positive electrode and the negative electrode of the battery cell 20. It should be noted that the pole ears 221 of the electrode assembly 22 are components formed by mutually stacking and connecting the regions on the positive electrode sheet that are not coated with the positive electrode active material layer, or components formed by mutually stacking and connecting the regions on the negative electrode sheet that are not coated with the negative electrode active material layer. If the pole ears 221 are used to output the positive electrode of the electrode assembly 22, the pole ears 221 are components formed by mutually stacking and connecting the regions on the positive electrode sheet that are not coated with the positive electrode active material layer; if the pole ears 221 are used to output the negative electrode of the electrode assembly 22, the pole ears 221 are components formed by mutually stacking and connecting the regions on the negative electrode sheet that are not coated with the negative electrode active material layer.

[0171] Exemplarily, the electrode terminal 23 may be made of a variety of materials. For example, the electrode terminal 23 may be made of copper, iron, aluminum, steel, or aluminum alloy.

[0172] Optionally, the electrode terminal 23 may be mounted on the housing 21 in various structures. Figure 3 and Figure 4 In the embodiment, the two electrode terminals 23 are both mounted on the end cap 216 of the outer shell 21. Of course, the structure of the battery cell 20 is not limited thereto. In other embodiments, the two electrode terminals 23 may be both mounted on the shell 215 of the outer shell 21. Similarly, one electrode terminal 23 may be mounted on the shell 215 of the outer shell 21, and the other electrode terminal 23 may be mounted on the end cap 216 of the outer shell 21.

[0173] In some embodiments, see Figure 4 As shown, the battery cell 20 may also include two current collecting components 24, both of which are arranged in the outer shell 21, and each current collecting component 24 is used to connect an electrode terminal 23 and a plurality of electrode lugs 221 with the same polarity in the electrode assemblies 22 to achieve electrical connection between the electrode terminal 23 and the electrode assembly 22, which is beneficial to reduce the difficulty of assembly between the lug 221 and the electrode terminal 23.

[0174] Exemplarily, the material of the current collecting component 24 may be various, for example, the material of the current collecting component 24 may be copper, iron, aluminum, steel or aluminum alloy.

[0175] In this embodiment, the housing 21 has a first wall 211 and a second wall 212 connected to each other, and a first groove 213 is provided on the first wall 211, so that the first wall 211 can be split along the first groove 213 when the battery cell 20 is depressurized, so as to release the internal pressure of the battery cell 20, wherein a second groove 214 is also provided on the first wall 211, and the first groove 213 has a first groove section 213a arranged in the first direction X with the second groove 214, and the second groove 214 is located between the first groove section 213a of the first groove 213 and the first outer surface 2121 of the second wall 212 in the first direction X, so that the second groove 214 can play a certain separation role between the area of ​​the first wall 211 where the first groove section 213a is provided and the second wall 212, on the one hand, the second groove 214 can absorb the extruded excess material of the first groove section 213a during the molding process of the first groove section 213a of the first groove 213, so as to ease the process of machining the first groove section 213a on the first wall 211 The first outer surface 2121 of the second wall 212 or the first wall 211 may be partially arched due to local extrusion, thereby reducing the problem of local size increase of the battery cell 20 in the first direction X or reduction in the flatness of the first wall 211, so as to improve the size consistency of the shell 21, which is beneficial to improving the production quality of the battery cell 20. On the other hand, when the battery cell 20 is subjected to internal and external impact forces and deformed, the second groove 214 can also absorb the deformation energy of the battery cell 20, so that the second groove 214 can play a buffering role between the first groove section 213a and the second wall 212, so as to play a certain protective role for the area of ​​the first wall 211 where the first groove section 213a is provided, so as to effectively reduce the deformation or damage of the area of ​​the first wall 211 where the first groove 213 is provided when the battery cell 20 is subjected to internal and external impact forces, so as to alleviate the situation of premature actuation and pressure relief of the battery cell 20 during use, which is beneficial to improving the reliability and service life of the battery cell 20.

[0176] According to some embodiments of the present application, see Figure 5 and Figure 6 As shown, along the first direction X, the minimum distance L1 between the first groove section 213a and the first outer surface 2121 is greater than or equal to 0.11 times the size L2 of the battery cell 20, and the minimum distance L1 between the first groove section 213a and the first outer surface 2121 is less than or equal to 0.44 times the size L2 of the battery cell 20, that is, in the first direction X, the minimum distance between the first groove section 213a and the first outer surface 2121 is L1, and the size of the battery cell 20 is L2, which satisfies 0.11≤L1 / L2≤0.44.

[0177] The minimum distance L1 between the first groove segment 213 a and the first outer surface 2121 is the minimum distance between the projection of the first groove segment 213 a in a plane perpendicular to the thickness direction Z of the first wall and the first outer surface 2121 .

[0178] Exemplarily, the outer shell 21 of the battery cell 20 is a rectangular parallelepiped structure. Correspondingly, L1 is the distance between the first groove section 213a and the first outer surface 2121 of the second wall 212 facing away from the electrode assembly 22 in the first direction X, and L2 is the thickness of the battery cell 20 in the first direction X.

[0179] Optionally, the ratio of the minimum distance L1 between the first groove segment 213a and the first outer surface 2121 in the first direction X to the thickness L2 of the battery cell 20 in the first direction X may be 0.11, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.35, 0.4 or 0.44, etc.

[0180] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail in conjunction with Comparative Examples 1-8 and Examples 1-16. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its applications. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0181] Comparative Example 1

[0182] 1) Preparation of positive electrode

[0183] The positive electrode active material LiNi 0.7 Co 0.1 Mn 0.1 O2, conductive agent Super P, and binder polyvinylidene fluoride (PVDF) are used to prepare positive electrode slurry in N-methylpyrrolidone (NMP), wherein the solid content in the positive electrode slurry is 50wt%, and the solid content of LiNi 0.7 Co 0.1 Mn 0.1 The mass ratio of O2, Super P and PVDF is 8:1:1. The positive electrode slurry is coated on the upper and lower surfaces of the current collector aluminum foil and dried at 85°C and then cold pressed. Then, it is trimmed, cut and stripped, and then dried at 85°C under vacuum conditions for 4 hours to make the positive electrode sheet.

[0184] 2) Preparation of negative electrode

[0185] Graphite, conductive agent Super P, thickener carboxymethyl cellulose (CMC), and adhesive styrene butadiene rubber (SBR) are mixed evenly in deionized water to prepare a negative electrode slurry, wherein the solid content in the negative electrode slurry is 30wt%, and the mass ratio of graphite, silicon oxide, Super P, CMC and adhesive styrene butadiene rubber (SBR) in the solid component is 88:7:3:2. The negative electrode slurry is coated on the upper and lower surfaces of the current collector copper foil and dried at 85°C, and then cold pressed, trimmed, cut into pieces, and slit, and then dried at 120°C under vacuum conditions for 12 hours to prepare a negative electrode sheet.

[0186] 3) Preparation of electrolyte

[0187] In an argon atmosphere glove box (H2O<0.1ppm, O2<0.1ppm), the fully dried electrolyte salt LiPF6 was dissolved in a mixed solvent (the mixed solvent included ethylene carbonate (EC) and diethyl carbonate (DEC), and ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a mass ratio of 50:50), and after mixing evenly, a liquid electrolyte with a concentration of 1 mol / L was obtained.

[0188] 4) Isolation parts

[0189] A 16 μm polyethylene film was used as a separator.

[0190] 5) Preparation of battery cell 20

[0191] The positive electrode sheet, the separator, and the negative electrode sheet are stacked in order, so that the separator is located between the positive and negative electrode sheets to isolate the positive and negative electrodes, and the electrode assembly 22 is wound, and the electrode assembly 22 is placed in an aluminum shell 21, and the prepared electrolyte is injected into the dried shell 21, and the battery cell 20 is prepared, and a first groove 213 and a second groove 214 are formed on the shell 21 of the battery cell 20. The shell 21 of the battery cell 20 of Comparative Example 1 is a rectangular parallelepiped structure (the first groove 213 is an "H"-shaped structure, that is, the first groove 213 includes a first groove segment 2 13a, a second slot section 213b and a third slot section 213c, the second slot section 213b and the third slot section 213c are arranged at intervals along the second direction Y and both extend along the first direction X, the first slot section 213a is connected between the second slot section 213b and the third slot section 213c, the first slot section 213a extends along the second direction Y, and the first slot section 213a is located in the middle of the first wall 211 in the first direction X), the thickness of the battery cell 20 in the first direction X is 39mm, the length in the second direction Y is 203mm, and the minimum distance L1 between the first slot section 213a and the first outer surface 2121 is 1.95mm.

[0192] The preparation methods of the battery cells 20 of Examples 1-4 and Comparative Example 2 are the same as that of Comparative Example 1, except that the minimum distance L1 between the first groove section 213a and the first outer surface 2121 is different, as shown in Table 1.

[0193] The preparation methods of the battery cells 20 of Examples 5-8 and Comparative Examples 3-4 are the same as that of Comparative Example 1. The thickness of the battery cells 20 of Examples 5-8 and Comparative Examples 3-4 in the first direction X is 25 mm, and the length in the second direction Y is 148 mm. The other difference is that the minimum distance L1 between the first groove segment 213a and the first outer surface 2121 is different. The specific situation is shown in Table 2.

[0194] The preparation methods of the battery cells 20 of Examples 9-12 and Comparative Examples 5-6 are the same as that of Comparative Example 1. The thickness of the battery cells 20 of Examples 9-12 and Comparative Examples 5-6 in the first direction X is 44 mm, and the length in the second direction Y is 203 mm. The other difference is that the minimum distance L1 between the first groove section 213a and the first outer surface 2121 is different. The specific situation is shown in Table 3.

[0195] The preparation methods of the battery cells 20 of Examples 13-16 and Comparative Examples 7-8 are the same as that of Comparative Example 1. The thickness of the battery cells 20 of Examples 13-16 and Comparative Examples 7-8 in the first direction X is 100 mm, and the length in the second direction Y is 203 mm. The other difference is that the minimum distance L1 between the first groove segment 213a and the first outer surface 2121 is different. The specific situation is shown in Table 4.

[0196] The first groove 213 is processed under different conditions by comparing the ratio of the minimum distance L1 between the first groove segment 213a and the first outer surface 2121 in the first direction X to the thickness L2 of the battery cell 20 in the first direction X through comparative examples 1-8 and embodiments 1-16. After the processing, the expansion value of the battery cell 20 in the first direction X is measured, and the flatness difference of the first wall 211 is measured. The specific measurement method is as follows:

[0197] Method for measuring the outward expansion value of the battery cell 20 in the first direction X: along the second direction Y, measure the thickness of the battery cell 20 in the first direction X at 5 mm away from the edge of the first wall 211 to obtain a reference value of the thickness of the battery cell 20 in the first direction X, then measure the thickness of the battery cell 20 in the first direction X at three areas of the first wall 211 where the first groove 213 is provided to obtain experimental value 1, experimental value 2 and experimental value 3 of the thickness of the battery cell 20 in the first direction X, and subtract the reference value from the average value of the experimental value 1, experimental value 2 and experimental value 3 to obtain the outward expansion value of the battery cell 20 in the first direction X.

[0198] Method for measuring the flatness difference of the first wall 211: in the area where the first groove 213 is not set on the first wall 211, four measuring points are taken near the two ends of the first wall 211 along the first direction X, the flatness of the four measuring points is measured, and the average value of the flatness of the four measuring points is calculated to obtain a reference value of the flatness, then two experimental points are taken on both sides of the first groove section 213a, the flatness of the four experimental points is measured, and the average value of the flatness of the four experimental points is calculated to obtain an experimental value of the flatness, and finally the reference value is subtracted from the experimental value to obtain the flatness difference of the first wall 211.

[0199] The experimental results of Comparative Examples 1-2 and Examples 1-4 are shown in Table 1 below:

[0200] Table 1

[0201]

[0202] The experimental results of Comparative Examples 3-4 and Examples 5-8 are shown in Table 2 below:

[0203] Table 2

[0204]

[0205] The experimental results of Comparative Examples 5-6 and Examples 9-12 are shown in Table 3 below:

[0206] Table 3

[0207]

[0208] The experimental results of Comparative Examples 7-8 and Examples 13-16 are shown in Table 4 below:

[0209] Table 4

[0210]

[0211] Referring to Tables 1 to 4, it can be seen from the experimental results of comparative examples 1 to 8 and embodiments 1 to 16 that after the ratio of the minimum distance between the first groove section 213a and the first outer surface 2121 to the size of the battery cell 20 in the first direction X is less than 0.11, the outward expansion value of the battery cell 20 in the first direction X reaches 0.5 mm and above, thereby causing the thickness of the battery cell 20 in the first direction X to have a relatively obvious outward expansion phenomenon, so that the consistency of the thickness of the battery cell 20 in the first direction X is poor, and the flatness difference of the first wall 211 reaches 0.5 mm and above, thereby causing the flatness of the first wall 211 to be poor. When the ratio of the minimum distance between the first groove section 213a and the first outer surface 2121 to the size of the battery cell 20 in the first direction X is greater than or equal to 0.11, the outward expansion value of the battery cell 20 in the first direction X can reach 0.4 mm and within 0.4 mm, and the flatness difference of the first wall 211 can reach 0.3 mm and within 0.3 mm, so that the second groove 214 arranged between the first groove section 213a and the first outer surface 2121 can have a good absorption effect on the extruded excess material of the first groove section 213a during the molding process of the first groove section 213a of the first groove 213, which is beneficial to improve the consistency of the size of the battery cell 20 in the first direction X and improve the flatness of the first wall 211. Therefore, the ratio of the minimum distance between the first groove section 213a and the first outer surface 2121 to the size of the battery cell 20 in the first direction X is set to be greater than or equal to 0.11.

[0212] Similarly, referring to Tables 1 to 4, it can be seen from the experimental results of comparative examples 1 to 8 and embodiments 1 to 16 that after the ratio of the minimum distance between the first groove section 213a and the first outer surface 2121 to the size of the battery cell 20 in the first direction X is greater than 0.44, the outward expansion value of the battery cell 20 in the first direction X reaches 0.5 mm and above, thereby causing the thickness of the battery cell 20 in the first direction X to have a more obvious outward expansion phenomenon, so that the consistency of the thickness of the battery cell 20 in the first direction X is poor, and the flatness difference of the first wall 211 reaches 0.4 mm and above, thereby causing the flatness of the first wall 211 to be poor. When the ratio of the minimum distance between the first groove section 213a and the first outer surface 2121 to the size of the battery cell 20 in the first direction X is less than or equal to 0.44, the outward expansion value of the battery cell 20 in the first direction X can reach 0.4 mm and within 0.4 mm, and the flatness difference of the first wall 211 can reach 0.3 mm and within 0.3 mm, so that the second groove 214 arranged between the first groove section 213a and the first outer surface 2121 can have a good absorption effect on the extruded excess material of the first groove section 213a during the molding process of the first groove section 213a of the first groove 213, thereby facilitating the improvement of the consistency of the size of the battery cell 20 in the first direction X and the improvement of the flatness of the first wall 211. Therefore, the ratio of the minimum distance between the first groove section 213a and the first outer surface 2121 to the size of the battery cell 20 in the first direction X is set to be less than or equal to 0.44.

[0213] In this embodiment, by setting the ratio of the minimum distance between the first groove segment 213a and the first outer surface 2121 to the size of the battery cell 20 in the first direction X to 0.11 to 0.44, the second groove 214 arranged between the first groove segment 213a and the first outer surface 2121 can better absorb the extruded excess material of the first groove segment 213a during the molding process of the first groove segment 213a of the first groove 213, thereby facilitating the improvement of the consistency of the size of the battery cell 20 in the first direction X and the improvement of the flatness of the first wall 211.

[0214] In some embodiments, see Figure 5 and Figure 6As shown, along the first direction X, the minimum distance L1 between the first groove section 213a and the first outer surface 2121 is greater than or equal to 0.15 times the size L2 of the battery cell 20, and the minimum distance L1 between the first groove section 213a and the first outer surface 2121 is less than or equal to 0.4 times the size L2 of the battery cell 20, that is, along the first direction X, the minimum distance between the first groove section 213a and the first outer surface 2121 is L1, and the size of the battery cell 20 is L2, satisfying 0.15≤L1 / L2≤0.4.

[0215] Among them, referring to Tables 1 to 4 above, it can be seen from the experimental results of Comparative Examples 1 to 8 and Examples 1 to 16 that when the ratio of the minimum distance between the first groove section 213a and the first outer surface 2121 to the size of the battery cell 20 in the first direction X is greater than or equal to 0.15 and less than or equal to 0.4, the expansion value of the battery cell 20 in the first direction X can reach 0.3 mm and within 0.3 mm, and the flatness difference of the first wall 211 can reach 0.2 mm and within 0.2 mm, so that the battery cell 20 disposed in the first groove section 213a can be arranged in the first outer surface 2121. The second groove 214 between a and the first outer surface 2121 can have a good absorption effect on the extruded excess material of the first groove segment 213a during the molding process of the first groove segment 213a of the first groove 213, thereby being beneficial to further improve the consistency of the size of the battery cell 20 in the first direction X, and being beneficial to further improve the flatness of the first wall 211. Therefore, the ratio of the minimum distance between the first groove segment 213a and the first outer surface 2121 to the size of the battery cell 20 in the first direction X is set to 0.15 to 0.4.

[0216] In this embodiment, by further setting the ratio of the minimum distance between the first groove segment 213a and the first outer surface 2121 to the size of the battery cell 20 in the first direction X to 0.15 to 0.4, the absorption effect of the second groove 214 on the extruded excess material of the first groove segment 213a during the molding process of the first groove segment 213a of the first groove 213 can be further improved, which is beneficial to further improve the flatness of the first wall 211 and to further improve the consistency of the size of the battery cell 20 in the first direction X.

[0217] According to some embodiments of the present application, see Figure 5 and Figure 6 As shown, along the first direction X, the minimum distance between the first groove segment 213a and the first outer surface 2121 is L1, which satisfies 10 mm ≤ L1 ≤ 44 mm.

[0218] Exemplarily, the minimum distance L1 between the first groove segment 213a and the first outer surface 2121 in the first direction X can be 10mm, 11mm, 12mm, 13mm, 15mm, 15.6mm, 17mm, 17.16mm, 17.6mm, 18mm, 19mm, 19.36mm, 20mm, 22mm, 25mm, 30mm, 35mm, 40mm or 44mm, etc.

[0219] In this embodiment, by setting the minimum distance between the first groove section 213a and the first outer surface 2121 in the first direction X to be greater than or equal to 10 mm, on the one hand, the size of the area between the first groove section 213a and the first outer surface 2121 in the first direction X can be increased, so as to reduce the difficulty of setting the second groove 214 between the first groove section 213a and the first outer surface 2121, and can alleviate the phenomenon that the second groove 214 cannot be set between the first groove section 213a and the first outer surface 2121, which is conducive to reducing the difficulty of manufacturing the battery cell 20. On the other hand, it can alleviate the phenomenon that the second groove 214 absorbs the residual material extruded during the molding process of the first groove section 213a due to the small distance between the first groove section 213a and the first outer surface 2121. It can reduce the phenomenon that the local size of the battery cell 20 increases or the flatness of the first wall 211 is poor due to local extrusion during the processing of the first groove section 213a of the first wall 211 of the shell 21, thereby effectively improving the size consistency of the shell 21. By setting the minimum distance between the first groove section 213a and the first outer surface 2121 in the first direction X to be less than or equal to 44 mm, the phenomenon of space waste or over-processing of the second groove 214 caused by the area between the first groove section 213a and the first outer surface 2121 being too large in the first direction X can be reduced, thereby facilitating reducing the manufacturing cost of the battery cell 20.

[0220] In some embodiments, see Figure 5 and Figure 6 As shown, along the first direction X, the size of the battery cell 20 is L2, which satisfies 25 mm ≤ L2 ≤ 100 mm.

[0221] For example, the dimension L2 of the battery cell 20 in the first direction X may be 25 mm, 28 mm, 30 mm, 35 mm, 39 mm, 40 mm, 44 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm or 100 mm.

[0222] In this embodiment, by setting the size of the battery cell 20 in the first direction X to be greater than or equal to 25 mm, on the one hand, the number or size of the electrode assembly 22 contained in the housing 21 can be increased, which is conducive to improving the energy density of the battery cell 20, and on the other hand, the problem of difficulty in manufacturing the battery cell 20 caused by the small size of the battery cell 20 in the first direction X can be alleviated, so as to reduce the difficulty in manufacturing the battery cell 20, thereby facilitating improving the production efficiency of the battery cell 20. By setting the size of the battery cell 20 in the first direction X to be less than or equal to 100 mm, the phenomenon of difficulty in subsequent assembly of the battery cell 20 caused by the large size of the battery cell 20 in the first direction X can be alleviated, and the difficulty in manufacturing the battery cell 20 can be reduced.

[0223] According to some embodiments of the present application, referring to Figure 6 , and please refer to Figure 7 , Figure 7 for Figure 6 The enlarged partial view of the portion A of the housing 21 is shown. Along the thickness direction Z of the first wall, the minimum residual thickness of the first groove 213 is D1, and the minimum residual thickness of the second groove 214 is D2, satisfying D2>D1.

[0224] The minimum residual thickness of the first groove 213 is D1, that is, along the thickness direction Z of the first wall, the minimum thickness of the portion of the first wall 211 corresponding to the groove bottom surface of the first groove 213 is D1, that is, the minimum thickness of the groove bottom wall of the first groove 213 in the thickness direction Z of the first wall is D1. It should be noted that, if the first groove 213 includes only one smooth groove section in the embodiment, the minimum residual thickness D1 of the first groove 213 is the minimum thickness of the residual portion of the first wall 211 at the groove section; if the first groove 213 includes multiple smooth groove sections in the embodiment, the minimum residual thickness D1 of the first groove 213 is the minimum value of the thickness of the residual portion of the first wall 211 at multiple groove sections.

[0225] The minimum residual thickness of the second groove 214 is D2, that is, along the thickness direction Z of the first wall, the minimum thickness of the portion of the first wall 211 corresponding to the bottom surface of the second groove 214 is D2, that is, the minimum thickness of the bottom wall of the second groove 214 in the thickness direction Z of the first wall is D2.

[0226] In this embodiment, by setting the minimum residual thickness of the first groove 213 to be smaller than the minimum residual thickness of the second groove 214, the strength of the area of ​​the first wall 211 where the first groove 213 is set is smaller than the strength of the area of ​​the first wall 211 where the second groove 214 is set, so that the first wall 211 of the outer shell 21 can preferentially crack along the first groove 213 and release the internal pressure of the battery cell 20, which helps to alleviate the phenomenon that the first wall 211 cracks from the area where the second groove 214 is set, causing poor pressure relief effect of the battery cell 20.

[0227] According to some embodiments of the present application, see Figure 5 and Figure 6 As shown, along the thickness direction Z of the first wall, the first wall 211 has a first surface 2111 and a second surface 2112 opposite to each other. The first groove 213 is disposed on the first surface 2111 , and the second groove 214 is disposed on the second surface 2112 .

[0228] The first surface 2111 and the second surface 2112 are surfaces on both sides of the first wall 211. Figure 6 In the embodiment, the first surface 2111 is the surface of the first wall 211 facing away from the interior of the housing 21 . Of course, in other embodiments, the first surface 2111 may also be the surface of the first wall 211 facing the interior of the housing 21 .

[0229] The first groove 213 is disposed on the first surface 2111 , and the second groove 214 is disposed on the second surface 2112 . That is, the first groove 213 and the second groove 214 are disposed on two sides of the first wall 211 , respectively.

[0230] In this embodiment, the first groove 213 and the second groove 214 are respectively arranged on the first surface 2111 and the second surface 2112 on both sides of the first wall 211, so that the first groove 213 and the second groove 214 are respectively located on both sides of the first wall 211, thereby facilitating the processing of the first groove 213 and the second groove 214 on both sides of the first wall 211, which is beneficial to reducing the mutual influence of the first groove 213 and the second groove 214 during the processing.

[0231] According to some embodiments of the present application, see Figure 6 As shown, along the first direction X, the projections of the first groove 213 and the second groove 214 overlap at least partially. That is, the projection of the second groove 214 in the first direction X covers at least part of the first groove segment 213 a of the first groove 213 .

[0232] In this embodiment, by arranging the projections of the first groove 213 and the second groove 214 in the first direction X to overlap at least part of each other, the second groove 214 and the first groove section 213a of the first groove 213 have mutually overlapping areas in the first direction X, so that, on the one hand, the absorption effect of the second groove 214 on the excess material squeezed out of the first groove section 213a during the molding process can be improved, so as to reduce the phenomenon that the local size of the battery cell 20 is increased or the flatness of the first wall 211 is poor due to local extrusion of material during the processing of the first groove section 213a of the first wall 211 of the shell 21; on the other hand, the absorption effect of the second groove 214 on the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deformed can be improved, so as to enhance the buffering effect of the second groove 214 between the first groove section 213a and the second wall 212, so as to effectively reduce the phenomenon that the area of ​​the first wall 211 where the first groove 213 is provided is deformed or damaged when the battery cell 20 is subjected to internal and external impact forces.

[0233] According to some embodiments of the present application, see Figure 6 As shown, along the thickness direction Z of the first wall, the bottom surface of the second groove 214 is closer to the first surface 2111 than the bottom surface of the first groove 213. That is, in the thickness direction Z of the first wall, the bottom surface of the second groove 214 is located between the first surface 2111 and the bottom surface of the first groove 213.

[0234] In this embodiment, the bottom surface of the second groove 214 is closer to the first surface 2111 than the bottom surface of the first groove 213 in the thickness direction Z of the first wall, so that the second groove 214 and the first groove section 213a of the first groove 213 have overlapping areas in the first direction X, so that on the one hand, the absorption effect of the second groove 214 on the residual material squeezed out of the first groove section 213a during the molding process can be improved, so as to reduce the phenomenon that the local size of the battery cell 20 is increased or the flatness of the first wall 211 is poor due to local extrusion of material during the processing of the first groove section 213a of the first wall 211 of the shell 21. On the other hand, the absorption effect of the second groove 214 on the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deformed can be improved, so as to improve the buffering effect of the second groove 214 between the first groove section 213a and the second wall 212, so as to effectively reduce the deformation or damage of the area of ​​the first wall 211 where the first groove 213 is provided when the battery cell 20 is subjected to internal and external impact forces.

[0235] According to some embodiments of the present application, see Figure 5 and Figure 6 As shown, along the thickness direction Z of the first wall, the maximum groove depth of the second groove 214 is H1, and the minimum residual thickness of the first groove 213 is D1, satisfying H1>D1.

[0236] The maximum groove depth H1 of the second groove 214 is the depth of a region of the second groove 214 where the groove depth is the largest.

[0237] In this embodiment, by setting the maximum groove depth of the second groove 214 to be greater than the minimum residual thickness of the first groove 213, the second groove 214 and the first groove section 213a of the first groove 213 have overlapping areas in the first direction X, so that on the one hand, the absorption effect of the second groove 214 on the residual material squeezed out of the first groove section 213a during the molding process can be improved, so as to reduce the phenomenon that the local size of the battery cell 20 is increased or the flatness of the first wall 211 is poor due to local extrusion of material during the processing of the first groove section 213a of the first wall 211 of the shell 21. On the other hand, the absorption effect of the second groove 214 on the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deformed can be improved, so as to enhance the buffering effect of the second groove 214 between the first groove section 213a and the second wall 212, so as to effectively reduce the deformation or damage of the area of ​​the first wall 211 where the first groove 213 is provided when the battery cell 20 is subjected to internal and external impact forces.

[0238] In some embodiments, along the thickness direction Z of the first wall, the ratio of the maximum groove depth of the first groove 213 to the thickness of the first wall 211 is greater than or equal to 0.16 and less than 1. It should be noted that, if the first groove 213 includes only one smooth groove segment in the embodiment, the maximum groove depth of the first groove 213 is the maximum depth of the groove segment; if the first groove 213 includes multiple smooth groove segments in the embodiment, the maximum groove depth of the first groove 213 is the maximum groove depth of the groove segment with the largest depth among the multiple groove segments.

[0239] Exemplarily, the ratio of the maximum groove depth of the first groove 213 in the thickness direction Z of the first wall to the thickness of the first wall 211 in the thickness direction Z of the first wall can be 0.16, 0.18, 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, 0.62, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.82, 0.85, 0.88, 0.9, 0.92, 0.95, 0.98, 0.99, etc., or any point value or a range value between any two of them.

[0240] In some embodiments, along the thickness direction Z of the first wall, the maximum groove depth of the first groove 213 is greater than or equal to 0.4 mm and less than or equal to 2 mm, and the thickness of the first wall 211 is greater than or equal to 0.8 mm and less than or equal to 2.5 mm.

[0241] Along the thickness direction Z of the first wall, the maximum groove depth of the first groove 213 can be 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, etc., any point value or a range value between any two of them.

[0242] Along the thickness direction Z of the first wall, the thickness of the first wall 211 can be any point value among 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, 2.05mm, 2.1mm, 2.15mm, 2.2mm, 2.25mm, 2.3mm, 2.35mm, 2.4mm, 2.45mm, 2.5mm, etc., or a range value between any two of them.

[0243] According to some embodiments of the present application, see Figure 6 and Figure 7 As shown, the first groove 213 is a multi-stage groove sequentially arranged from the first surface 2111 to the second surface 2112. Along the thickness direction Z of the first wall, in two adjacent grooves, the first-stage groove far from the first surface 2111 is arranged on the groove bottom surface of the first-stage groove close to the first surface 2111. Among the multi-stage grooves, the groove arranged on the first surface 2111 is the first-stage groove 2131. Along the first direction X, the second groove 214 at least partially overlaps with the projection of the first-stage groove 2131.

[0244] The first groove 213 is a multi-level groove sequentially arranged along the direction from the first surface 2111 to the second surface 2112 , that is, the first groove 213 is a stepped groove structure arranged on the first surface 2111 .

[0245] The grooves in the multi-level grooves arranged on the first surface 2111 are the first-level grooves 2131, that is, the grooves in the multi-level grooves of the first groove 213 that penetrate the first surface 2111 are the first-level grooves 2131. Figure 6 and Figure 7In the figure, the first groove 213 is a three-level groove, including a first-level groove 2131, a second-level groove 2132 and a third-level groove 2133 arranged in sequence. The first-level groove 2131 is arranged on the first surface 2111, the second-level groove 2132 is arranged on the bottom surface of the first-level groove 2131, and the third-level groove 2133 is arranged on the bottom surface of the second-level groove 2132. Of course, in other embodiments, the first groove 213 can also be a two-level groove, a four-level groove, a five-level groove or a six-level groove, etc.

[0246] Along the first direction X, the second groove 214 overlaps at least part of the projection of the first-stage groove 2131 , that is, the projection of the second groove 214 in the first direction X covers at least part of the first-stage groove 2131 of the first groove segment 213 a .

[0247] It should be noted that the first groove 213 is a multi-stage groove, and correspondingly, the first groove section 213 a of the first groove 213 is also a multi-stage groove structure.

[0248] In this embodiment, the first groove 213 is arranged as a multi-stage groove along the thickness direction Z of the first wall, and the second groove 214 and the first-stage groove 2131 of the first groove 213 are arranged to overlap at least part of the projection in the first direction X, so that the second groove 214 can cover the other multi-stage grooves arranged on the groove bottom surface of the first-stage groove 2131 in the first groove section 213a in the first direction X, so that on the one hand, the absorption effect of the second groove 214 on the residual material extruded from the first groove section 213a during the molding process of the multi-stage groove can be improved, so as to further reduce the first wall 211 of the shell 21 during the addition. On the one hand, the local size of the battery cell 20 may be increased or the flatness of the first wall 211 may be poor due to local extrusion during the process of forming the first groove section 213a. On the other hand, the absorption effect of the second groove 214 on the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deformed can be further enhanced, so as to further enhance the buffering effect of the second groove 214 between the first groove section 213a and the second wall 212, thereby further reducing the deformation or damage of the area of ​​the first wall 211 where the first groove 213 is provided when the battery cell 20 is subjected to internal and external impact forces.

[0249] According to some embodiments of the present application, see Figure 6 and Figure 7As shown, the first groove 213 is a multi-stage groove sequentially arranged from the first surface 2111 to the second surface 2112. Along the thickness direction Z of the first wall, in two adjacent grooves, the first-stage groove far from the first surface 2111 is arranged at the groove bottom surface of the first-stage groove close to the first surface 2111. The groove arranged on the first surface 2111 among the multi-stage grooves is the first-stage groove 2131. Along the thickness direction Z of the first wall, the groove bottom surface of the second groove 214 is flush with the groove bottom surface of the first-stage groove 2131 or the groove bottom surface of the second groove 214 is closer to the first surface 2111 than the groove bottom surface of the first-stage groove 2131.

[0250] Among them, the bottom surface of the second groove 214 is closer to the first surface 2111 than the bottom surface of the first-level groove 2131, that is, in the thickness direction Z of the first wall, the bottom surface of the second groove 214 is located between the bottom surface of the first-level groove 2131 of the first groove 213 and the first surface 2111.

[0251] In this embodiment, the first groove 213 is arranged as a multi-stage groove along the thickness direction Z of the first wall, and the groove bottom surface of the second groove 214 is arranged in the thickness direction Z of the first wall to be flush with the groove bottom surface of the first-stage groove 2131 or closer to the first surface 2111 than the groove bottom surface of the first-stage groove 2131, so that the second groove 214 can cover the other multi-stage grooves arranged on the groove bottom surface of the first-stage groove 2131 in the first groove segment 213a in the first direction X, thereby improving the absorption effect of the second groove 214 on the excess material extruded from the first groove segment 213a during the molding process of the multi-stage groove, so as to further reduce the external The first wall 211 of the shell 21 can prevent the local size of the battery cell 20 from increasing or the flatness of the first wall 211 from being poor due to local extrusion during the processing of the first groove section 213a. On the other hand, the absorption effect of the second groove 214 on the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deformed can be further enhanced, so as to further enhance the buffering effect of the second groove 214 between the first groove section 213a and the second wall 212, thereby further reducing the deformation or damage of the area of ​​the first wall 211 where the first groove 213 is provided when the battery cell 20 is subjected to internal and external impact forces.

[0252] According to some embodiments of the present application, see Figure 6 and Figure 7As shown, the first groove 213 is a multi-level groove sequentially arranged from the first surface 2111 to the second surface 2112. Along the thickness direction Z of the first wall, in two adjacent grooves, the first-level groove far from the first surface 2111 is arranged on the groove bottom surface of the first-level groove close to the first surface 2111. The groove arranged on the first surface 2111 among the multi-level grooves is the first-level groove 2131, the maximum groove depth of the second groove 214 is H1, and the minimum residual thickness of the first-level groove 2131 is D3, satisfying that H1≥D3.

[0253] The minimum residual thickness of the first-level groove 2131 is D3, that is, along the thickness direction Z of the first wall, the minimum thickness of the portion of the first wall 211 corresponding to the groove bottom surface of the first-level groove 2131 of the first groove 213 is D3, that is, the minimum thickness of the groove bottom wall of the first-level groove 2131 of the first groove 213 in the thickness direction Z of the first wall is D3. It should be noted that, if the first groove 213 includes only one smooth groove segment in the embodiment, the minimum residual thickness D3 of the first-level groove 2131 is the minimum thickness of the residual portion of the first wall 211 at the first-level groove 2131 of the groove segment; if the first groove 213 includes multiple smooth groove segments in the embodiment, the minimum residual thickness D3 of the first-level groove 2131 is the minimum value of the thickness of the residual portion of the first wall 211 at the first-level groove 2131 of the multiple groove segments.

[0254] In this embodiment, the first groove 213 is arranged as a multi-stage groove along the thickness direction Z of the first wall, and the maximum groove depth of the second groove 214 is greater than or equal to the minimum residual thickness of the first-stage groove 2131 in the multi-stage groove, so that the second groove 214 can cover the other multi-stage grooves arranged on the groove bottom surface of the first-stage groove 2131 in the first groove section 213a in the first direction X, so that on the one hand, the absorption effect of the second groove 214 on the residual material extruded from the first groove section 213a during the molding process of the multi-stage groove can be improved, so as to further reduce the first wall 211 of the shell 21 in the processing of the first groove On the one hand, it can prevent the local size of the battery cell 20 from increasing or the flatness of the first wall 211 from being poor due to local extrusion during the process of segment 213a. On the other hand, it can further enhance the absorption effect of the second groove 214 on the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deformed, so as to further enhance the buffering effect of the second groove 214 between the first groove segment 213a and the second wall 212, thereby further reducing the deformation or damage of the area of ​​the first wall 211 where the first groove 213 is provided when the battery cell 20 is subjected to internal and external impact forces.

[0255] According to some embodiments of the present application, referring to Figure 8 and Fig. 9 , Figure 8A bottom view of a housing 21 of a battery cell 20 provided in some other embodiments of the present application, Fig. 9 The partial cross-sectional view of the housing 21 of the battery cell 20 provided in some embodiments of the present application. Along the thickness direction Z of the first wall, the first wall 211 has a first surface 2111 and a second surface 2112 opposite to each other, and the first groove 213 and the second groove 214 are both disposed on the first surface 2111 .

[0256] The first groove 213 and the second groove 214 are both disposed on the first surface 2111 , that is, the first groove 213 and the second groove 214 are disposed on the same side of the first wall 211 in the thickness direction Z of the first wall.

[0257] For example, in Fig. 9 In the embodiment, the first surface 2111 is the surface of the first wall 211 facing away from the interior of the shell 21, that is, the first groove 213 and the second groove 214 are both arranged on the side of the first wall 211 facing away from the interior of the shell 21. Of course, in other embodiments, the first surface 2111 can also be the surface of the first wall 211 facing the interior of the shell 21, that is, the first groove 213 and the second groove 214 are both arranged on the side of the first wall 211 facing the interior of the shell 21.

[0258] In this embodiment, the first groove 213 and the second groove 214 are both arranged on the first surface 2111 of the first wall 211, so that the first groove 213 and the second groove 214 are located on the same side of the first wall 211, so that the first groove 213 and the second groove 214 are both processed on the same side of the first wall 211. On the one hand, it is convenient to realize the mutual spacing and avoidance between the first groove 213 and the second groove 214 during the processing, which is conducive to reducing the difficulty of processing the first groove 213 and the second groove 214 on the first wall 211. On the other hand, the processing of the first groove 213 and the second groove 214 can be realized without flipping the first wall 211, which is conducive to optimizing the production rhythm of the battery cell 20.

[0259] According to some embodiments of the present application, see Fig. 9 As shown, the first groove 213 is a multi-stage groove sequentially arranged from the first surface 2111 to the second surface 2112. Along the thickness direction Z of the first wall, in two adjacent grooves, the first-stage groove far from the first surface 2111 is arranged at the groove bottom surface of the first-stage groove close to the first surface 2111. Among the multi-stage grooves, the groove arranged on the first surface 2111 is the first-stage groove 2131. Along the thickness direction Z of the first wall, the groove bottom surface of the first-stage groove 2131 is closer to the first surface 2111 than the groove bottom surface of the second groove 214.

[0260] The first groove 213 is a multi-level groove sequentially arranged along the direction from the first surface 2111 to the second surface 2112 , that is, the first groove 213 is a stepped groove structure arranged on the first surface 2111 .

[0261] The grooves in the multi-level grooves arranged on the first surface 2111 are the first-level grooves 2131, that is, the grooves in the multi-level grooves of the first groove 213 that penetrate the first surface 2111 are the first-level grooves 2131. Fig. 9 In the figure, the first groove 213 is a three-level groove, including a first-level groove 2131, a second-level groove 2132 and a third-level groove 2133 arranged in sequence. The first-level groove 2131 is arranged on the first surface 2111, the second-level groove 2132 is arranged on the bottom surface of the first-level groove 2131, and the third-level groove 2133 is arranged on the bottom surface of the second-level groove 2132. Of course, in other embodiments, the first groove 213 can also be a two-level groove, a four-level groove, a five-level groove or a six-level groove, etc.

[0262] Along the thickness direction Z of the first wall, the bottom surface of the first-level groove 2131 is closer to the first surface 2111 than the bottom surface of the second groove 214. That is, in the thickness direction Z of the first wall, the bottom surface of the first-level groove 2131 of the first groove 213 is located between the first surface 2111 and the bottom surface of the second groove 214, that is, the groove depth of the second groove 214 is greater than the groove depth of the first-level groove 2131.

[0263] It should be noted that the first groove 213 is a multi-stage groove, and correspondingly, the first groove section 213 a of the first groove 213 is also a multi-stage groove structure.

[0264] In this embodiment, the bottom surface of the first-stage groove 2131 is closer to the first surface 2111 than the bottom surface of the second groove 214 in the thickness direction Z of the first wall, so that the second groove 214 is a structure of the first-stage groove 2131 covering the first groove section 213a in the first direction X, so that on the one hand, the absorption effect of the second groove 214 on the residual material squeezed out of the first groove section 213a in the process of forming the multi-stage groove can be improved, so as to reduce the phenomenon that the local size of the battery cell 20 is increased or the flatness of the first wall 211 is poor due to local squeezing of material in the process of processing the first groove section 213a of the first wall 211 of the shell 21. On the other hand, the absorption effect of the second groove 214 on the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deformed can be improved, so as to improve the buffering effect of the second groove 214 between the first groove section 213a and the second wall 212, so as to effectively reduce the phenomenon that the area of ​​the first wall 211 where the first groove 213 is provided is deformed or damaged when the battery cell 20 is subjected to internal and external impact forces.

[0265] According to some embodiments of the present application, see Fig. 9As shown, the first groove 213 is a multi-level groove sequentially arranged from the first surface 2111 to the second surface 2112. Along the thickness direction Z of the first wall, in two adjacent grooves, the first-level groove far from the first surface 2111 is arranged at the groove bottom surface of the first-level groove close to the first surface 2111. Among the multi-level grooves, the groove arranged on the first surface 2111 is the first-level groove 2131. Along the thickness direction Z of the first wall, the maximum groove depth of the second groove 214 is H1, and the maximum groove depth of the first-level groove 2131 is H2, satisfying H1>H2.

[0266] It should be noted that, if in an embodiment in which the first groove 213 includes only one smooth groove segment, the maximum groove depth H2 of the first-level groove 2131 is the maximum depth of the first-level groove 2131 in the groove segment; if in an embodiment in which the first groove 213 includes multiple smooth groove segments, the maximum groove depth H2 of the first-level groove 2131 is the maximum groove depth of the first-level groove 2131 in the groove segment with the largest depth among the multiple groove segments.

[0267] In this embodiment, by setting the maximum groove depth of the second groove 214 to be greater than the maximum groove depth of the first-stage groove 2131 in the multi-stage groove of the first groove 213, the second groove 214 is a structure of the first-stage groove 2131 covering the first groove segment 213a in the first direction X, so that on the one hand, the absorption effect of the second groove 214 on the residual material squeezed out of the first groove segment 213a in the process of forming the multi-stage groove can be improved, so as to reduce the phenomenon that the local size of the battery cell 20 is increased or the flatness of the first wall 211 is poor due to local squeezing of material in the process of processing the first groove segment 213a of the first wall 211 of the shell 21. On the other hand, the absorption effect of the second groove 214 on the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deformed can be improved, so as to enhance the buffering effect of the second groove 214 between the first groove segment 213a and the second wall 212, so as to effectively reduce the phenomenon that the area of ​​the first wall 211 where the first groove 213 is provided is deformed or damaged when the battery cell 20 is subjected to internal and external impact forces.

[0268] According to some embodiments of the present application, see Figure 6 and Fig. 9 As shown, the first surface 2111 is the surface of the first wall 211 facing away from the inside of the housing 21. That is, the first surface 2111 is the surface of the first wall 211 in the thickness direction Z of the first wall facing away from the electrode assembly 22.

[0269] In this embodiment, by setting the first surface 2111 of the first wall 211 as the surface of the side of the first wall 211 away from the interior of the outer shell 21, the first groove 213 is set on the side of the first wall 211 away from the interior of the outer shell 21, thereby facilitating the formation of the first groove 213 on the first wall 211 of the outer shell 21, which helps to reduce the processing difficulty of the first groove 213 and improve the production efficiency of the battery cell 20.

[0270] According to some embodiments of the present application, see Figure 5 and Figure 6 as well as Figure 8 and Fig. 9 As shown, the housing 21 of the battery cell 20 is a rectangular parallelepiped structure. Along the first direction X, the housing 21 has two second walls 212 arranged opposite to each other in the first direction X. The two second walls 212 are respectively connected to the two sides of the first wall 211. Along the first direction X, the first groove section 213a is located between the two second walls 212, and the first groove section 213a and the first outer surfaces 2121 of the two second walls 212 are each provided with a second groove 214.

[0271] In which, the shell 21 has two second walls 212 arranged opposite to each other in the first direction X, and the two second walls 212 are respectively connected to the two sides of the first wall 211, that is, the two second walls 212 are respectively connected to the two ends of the first wall 211 in the first direction X, and the two second walls 212 are perpendicular to the first wall 211.

[0272] A second groove 214 is provided between the first groove section 213a and the first outer surfaces 2121 of the two second walls 212, that is, a second groove 214 is provided on both sides of the first groove section 213a in the first direction X, so that the first groove section 213a is located between the two second grooves 214 in the first direction X.

[0273] In this embodiment, the housing 21 has two second walls 212 located on both sides of the first wall 211 in the first direction X, and a second groove 214 is provided between the two second walls 212 and the first groove section 213a, so that the first groove section 213a is located between the two second grooves 214 in the first direction X. On the one hand, the two second grooves 214 can absorb the excess material squeezed out from both sides during the molding process of the first groove section 213a, so as to further reduce the phenomenon that the local size of the battery cell 20 is increased or the flatness of the first wall 211 is poor due to local extrusion during the processing of the first groove section 213a of the first wall 211 of the housing 21. On the other hand, the two second grooves 214 can protect the battery cell 20 from both sides of the first groove section 213a, so as to absorb the deformation energy transmitted from both sides of the first groove section 213a when the battery cell 20 is subjected to internal and external impact forces, so as to further reduce the phenomenon that the area of ​​the first wall 211 provided with the first groove 213 is deformed or damaged when the battery cell 20 is subjected to internal and external impact forces.

[0274] According to some embodiments of the present application, see Figure 5 and Figure 8 As shown, the first wall 211 is a rectangular structure, and the width direction of the first wall 211 and the thickness direction of the second wall 212 are both parallel to the first direction X.

[0275] The thickness direction of the second wall 212 is the first direction X, and the thickness direction of the second wall 212 is perpendicular to the thickness direction Z of the first wall. Correspondingly, the width direction of the first wall 211 is the first direction X, and the length direction of the first wall 211 is the second direction Y.

[0276] In this embodiment, the first wall 211 is a rectangular structure, so that the shell 21 of the battery cell 20 is a rectangular parallelepiped structure, and the width direction of the first wall 211 and the thickness direction of the second wall 212 both extend along the first direction X, so that the second groove 214 is located on one side of the first groove section 213a in the width direction of the first wall 211, so that the second groove 214 is set on the side that is extremely easy to deform or extremely easy to be affected by impact during the molding process of the first groove section 213a, thereby facilitating the improvement of the buffering and protection effect of the second groove 214 on the first groove section 213a.

[0277] According to some embodiments of this application, see Figure 5 and Figure 8 As shown, along the thickness direction Z of the first wall, the two ends of the projection of the second groove 214 in its extension direction respectively extend out of the two ends of the projection of the first groove segment 213 a .

[0278] Among them, the two ends of the projection of the second groove 214 in its extension direction respectively extend out of the two ends of the projection of the first groove section 213a, that is, the size of the second groove 214 in its extension direction is larger than the first groove section 213a, and the two ends of the second groove 214 in its extension direction respectively exceed the two ends of the first groove section 213a.

[0279] In this embodiment, along the thickness direction Z of the first wall, by setting the projection of the second groove 214 in its extension direction to extend out of the two ends of the projection of the first groove section 213a respectively, the second groove 214 is made to be a structure in which the two ends in its extension direction respectively exceed the two ends of the first groove section 213a, thereby enhancing the separation effect of the second groove 214 between the first groove section 213a and the second wall 212, so as to enhance the absorption effect of the second groove 214 on the residual material extruded during the molding process of the first groove section 213a, and enhance the blocking effect of the second groove 214 on the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces.

[0280] In some embodiments, see Figure 5 and Figure 8 As shown, the second groove 214 extends along the second direction Y. Along the second direction Y, two ends of the second groove 214 extend out of two ends of the first groove section 213a respectively. The first direction X, the second direction Y and the thickness direction Z of the first wall are perpendicular to each other.

[0281] For example, in Figure 5 and Figure 8 In the embodiment, the second groove 214 and the first groove section 213a are both straight line structures extending along the second direction Y.

[0282] In this embodiment, by setting the second groove 214 as a structure extending along the second direction Y, it is helpful to improve the regularity of the shape of the second groove 214, thereby reducing the difficulty of processing the second groove 214, and it is convenient to set the second groove 214 to a structure where both ends in the second direction Y respectively exceed the two ends of the first groove section 213a, so as to reduce the difficulty of manufacturing the battery cell 20, which is beneficial to improve the production efficiency of the battery cell 20.

[0283] According to some embodiments of the present application, referring to Fig.10 , Fig.10 A bottom view of the housing 21 of the battery cell 20 provided in some other embodiments of the present application. The first groove 213 may further include a second groove section 213b, the first groove section 213a is connected to the second groove section 213b, the first groove section 213a and the second groove section 213b jointly define a predetermined pressure relief area 2113, and the predetermined pressure relief area 2113 is configured to be opened when the first wall 211 is cracked along at least a portion of the first groove 213 to release the internal pressure of the battery cell 20.

[0284] Among them, the first groove section 213a and the second groove section 213b jointly define a predetermined pressure relief area 2113, that is, the first groove section 213a and the second groove section 213b are structures arranged along the edge of the predetermined pressure relief area 2113, so that the setting trajectory of the first groove 213 is arranged along the edge of the predetermined pressure relief area 2113.

[0285] The predetermined pressure relief area 2113 is configured to be able to be opened when the first wall 211 is cracked along at least a portion of the first groove 213, that is, when the battery cell 20 undergoes thermal runaway and releases internal pressure, the area of ​​the wall where the first groove section 213a and the second groove section 213b are arranged can be cracked, so that the predetermined pressure relief area 2113 can be opened and the internal pressure of the battery cell 20 can be released.

[0286] For example, in Fig.10 In the embodiment, one end of the first slot segment 213a is connected to one end of the second slot segment 213b, and the second slot segment 213b extends along the first direction X, so that the first slot segment 213a and the second slot segment 213b form a first groove 213 of an "L"-shaped structure. Of course, in other embodiments, one end of the first slot segment 213a may also be connected to the middle position of the second slot segment 213b, see Figure 5 As shown, the wall portion forms a predetermined pressure relief area 2113 on both sides of the first slot section 213a.

[0287] It should be noted that in the embodiment where the first groove 213 is a multi-stage groove, the first groove section 213a and the second groove section 213b are both multi-stage groove structures.

[0288] In this embodiment, the first groove 213 also has a second groove section 213b, and the second groove section 213b and the first groove section 213a are interconnected, so that the first groove section 213a and the second groove section 213b jointly define a predetermined pressure relief area 2113. On the one hand, the pressure relief area of ​​the battery cell 20 can be increased to increase the pressure relief rate of the battery cell 20. On the other hand, the position where the first groove section 213a and the second groove section 213b are interconnected is weaker, which is easier to crack and open the predetermined pressure relief area 2113 to release the internal pressure of the battery cell 20.

[0289] According to some embodiments of the present application, see Figure 5 and Figure 8As shown, the first groove 213 may further include a second groove section 213b and a third groove section 213c, the second groove section 213b and the third groove section 213c are arranged opposite to each other along the second direction Y, and the second direction Y is perpendicular to the first direction X. The first groove section 213a connects the second groove section 213b and the third groove section 213c, and the first groove section 213a, the second groove section 213b and the third groove section 213c jointly define a predetermined pressure relief area 2113, and the predetermined pressure relief area 2113 is configured to be opened and flipped around the second groove 214 when the first wall 211 is cracked along the first groove 213, so as to release the internal pressure of the battery cell 20.

[0290] The second slot segment 213b and the third slot segment 213c are arranged opposite to each other along the second direction Y, that is, the second slot segment 213b and the third slot segment 213c are arranged at intervals along the second direction Y. Figure 5 and Figure 8 In the embodiment, the second slot segment 213b and the third slot segment 213c both extend along the first direction X.

[0291] The first slot segment 213a connects the second slot segment 213b and the third slot segment 213c, that is, the first slot segment 213a is located between the second slot segment 213b and the third slot segment 213c, and the two ends of the first slot segment 213a are respectively connected to the second slot segment 213b and the third slot segment 213c. Of course, in other embodiments, the first slot segment 213a can also extend the second slot segment 213b and the third slot segment 213c at both ends in the second direction Y.

[0292] The first slot section 213a, the second slot section 213b and the third slot section 213c jointly define a predetermined pressure relief area 2113, that is, the first slot section 213a, the second slot section 213b and the third slot section 213c can enclose at least one predetermined pressure relief area 2113 on the first wall 211, and the first slot section 213a, the second slot section 213b and the third slot section 213c are structures arranged along the edge of the predetermined pressure relief area 2113, so that the predetermined pressure relief area 2113 can be formed by the first The groove section 213a, the second groove section 213b and the third groove section 213c are opened as boundaries, that is, a predetermined pressure relief area 2113 is formed in the area enclosed by the first groove section 213a, the second groove section 213b and the third groove section 213c, so that the part of the first wall 211 located in the predetermined pressure relief area 2113 can be opened with the first groove section 213a, the second groove section 213b and the third groove section 213c as boundaries when the battery cell 20 is depressurized, thereby releasing the internal pressure of the battery cell 20.

[0293] Alternatively, see Figure 5 and Figure 8As shown, the shape of the first groove 213 formed by the first groove section 213a, the second groove section 213b and the third groove section 213c can be an "H"-shaped structure to form two predetermined pressure relief areas 2113 on the first wall 211, and the two predetermined pressure relief areas 2113 are respectively located on both sides of the first groove section 213a in the first direction X. Of course, the first groove 213 can also be other structures, refer to Fig.11 , Fig.11 Bottom view of the housing 21 of the battery cell 20 provided in some other embodiments of the present application. The first groove 213 formed by the first groove section 213a, the second groove section 213b and the third groove section 213c may be in a "U"-shaped structure, that is, one end of the first groove section 213a is connected to one end of the second groove section 213b, and the other end is connected to one end of the third groove section 213c, so as to form a predetermined pressure relief area 2113 on the first wall 211.

[0294] It should be noted that in the embodiment where the first groove 213 is a multi-stage groove, the first groove section 213a, the second groove section 213b and the third groove section 213c are all multi-stage groove structures.

[0295] In this embodiment, the first groove 213 also includes a third groove section 213c arranged opposite to the second groove section 213b on the second side, and the first groove section 213a connects the second groove section 213b and the third groove section 213c, so that the first wall 211 can be split along the first groove section 213a, the second groove section 213b and the third groove section 213c when the battery cell 20 is depressurized, so as to open the predetermined pressure relief area 2113 to release the internal pressure of the battery cell 20. The first groove 213 with this structure makes the intersection position of the first groove section 213a and the second groove section 213b and the connection position of the first groove section 213a and the third groove section 213c weaker, easier to split and open the predetermined pressure relief area 2113 for pressure relief, and can further increase the pressure relief area and pressure relief rate of the battery cell 20. In addition, since the second groove 214 and the first groove section 213a are arranged along the first direction X, the predetermined pressure relief area 2113 defined by the first groove section 213a, the second groove section 213b and the third groove section 213c can also be flipped around the second groove 214 as the axis when being opened, which is beneficial to improving the effect and degree of opening of the predetermined pressure relief area 2113, so as to further improve the pressure relief effect of the battery cell 20.

[0296] In some embodiments, see Figure 5 and Figure 8 As shown, the connection position of the second slot section 213b and the first slot section 213a deviates from the two ends of the second slot section 213b, and the connection position of the third slot section 213c and the first slot section 213a deviates from the two ends of the third slot section 213c, so that a predetermined pressure relief area 2113 is formed on both sides of the first slot section 213a.

[0297] Among them, the connection position of the second groove segment 213b and the first groove segment 213a deviates from the two ends of the second groove segment 213b, that is, the first groove segment 213a is connected between the two ends of the second groove segment 213b. Similarly, the connection position of the third groove segment 213c and the first groove segment 213a deviates from the two ends of the third groove segment 213c, that is, the first groove segment 213a is connected between the two ends of the third groove segment 213c, so that the shape of the first groove 213 formed by the first groove segment 213a, the second groove segment 213b and the third groove segment 213c is a structure that is approximately "H" shaped.

[0298] In this embodiment, by setting the connection position of the second groove section 213b and the first groove section 213a to be located between the two ends of the second groove section 213b, and setting the connection position of the third groove section 213c and the first groove section 213a to be located between the two ends of the third groove section 213c, so that the first groove section 213a, the second groove section 213b and the third groove section 213c form a structure similar to an "H" shape, so that both sides of the first groove section 213a of the first groove 213 can form a predetermined pressure relief area 2113, and the two predetermined pressure relief areas 2113 can be opened in a split manner for pressure relief when the battery cell 20 is depressurized, which is beneficial to further increase the pressure relief effect of the battery cell 20 and can effectively improve the pressure relief rate of the battery cell 20.

[0299] In some embodiments, see Figure 5 and Figure 8 As shown, the first slot section 213a, the second slot section 213b and the third slot section 213c all extend along a straight line, and the second slot section 213b and the third slot section 213c are perpendicular to the first slot section 213a. That is, the extension direction of the first slot section 213a is perpendicular to the extension direction of the second slot section 213b and the extension direction of the third slot section 213c, so that the shape of the first groove 213 formed by the first slot section 213a, the second slot section 213b and the third slot section 213c is a regular "H"-shaped structure, and predetermined pressure relief areas 2113 are formed on both sides of the first slot section 213a. Of course, the areas of the two predetermined pressure relief areas 2113 may be the same or different.

[0300] Exemplarily, the first slot segment 213a is a linear structure extending along the second direction Y, the second slot segment 213b and the third slot segment 213c are both linear structures extending along the first direction X, and the first slot segment 213a is located between the second slot segment 213b and the third slot segment 213c along the second direction Y.

[0301] In this embodiment, by setting the second groove section 213b and the third groove section 213c to be perpendicular to the first groove section 213a, the extension direction of the first groove section 213a is made to be the arrangement direction of the second groove section 213b and the third groove section 213c. On the one hand, the regularity of the shape of the first groove 213 can be improved, which is beneficial to reduce the processing difficulty of the first groove 213, so as to reduce the manufacturing cost of the battery cell 20. On the other hand, it is convenient for the two predetermined pressure relief areas 2113 on the first wall 211 located on both sides of the first groove section 213a to relieve pressure in opposite directions when the battery cell 20 is relieved.

[0302] According to some embodiments of the present application, referring to Fig.12 , Fig.12 The bottom view of the housing 21 of the battery cell 20 provided in some other embodiments of the present application. The first groove section 213a, the second groove section 213b and the third groove section 213c all extend along an arc trajectory.

[0303] For example, in Fig.12 In the embodiment, two ends of the first groove segment 213a are respectively connected to one end of the second groove segment 213b and one end of the third groove segment 213c, and the first groove segment 213a, the second groove segment 213b and the third groove segment 213c all extend along an arc trajectory, so that the first groove segment 213a, the second groove segment 213b and the third groove segment 213c form a first groove 213 similar to a "C"-shaped structure.

[0304] In this embodiment, by setting the first groove section 213a, the second groove section 213b and the third groove section 213c as structures extending along an arc trajectory, it is beneficial to improve the arc degree of the connection position of the first groove section 213a and the second groove section 213b, and the arc degree of the connection position of the first groove section 213a and the third groove section 213c can be improved. On the one hand, it can reduce the difficulty of processing the first groove 213, and on the other hand, it can facilitate the first wall 211 to open the predetermined pressure relief area 2113 to release the internal pressure of the battery cell 20 after it is split along the first groove section 213a, the second groove section 213b and the third groove section 213c.

[0305] According to some embodiments of the present application, see Figure 5 and Figure 8 As shown, the first groove 213 may further include a fourth groove section 213d, the fourth groove section 213d is located between the second groove section 213b and the third groove section 213c, and the fourth groove section 213d is connected to the first groove section 213a.

[0306] Exemplarily, the fourth slot segment 213d extends along the first direction X, and the fourth slot segment 213d and the first slot segment 213a are perpendicular to each other.

[0307] Exemplarily, the distance between the fourth slot segment 213d and the second slot segment 213b in the second direction Y is equal to the distance between the fourth slot segment 213d and the third slot segment 213c in the second direction Y.

[0308] It should be noted that in the embodiment where the first groove 213 is a multi-stage groove, the fourth groove section 213 d is also a multi-stage groove structure.

[0309] In this embodiment, the first groove 213 is further provided with a fourth groove section 213d located between the second groove section 213b and the third groove section 213c, and the fourth groove section 213d is interconnected with the first groove section 213a, so that the stress at the position where the fourth groove section 213d and the first groove section 213a are interconnected is more concentrated and easier to break, so that the first wall 211 can break along the first groove section 213a from the position where the first groove section 213a and the fourth groove section 213d intersect, and break along the second groove section 213b and the third groove section 213c after the first groove section 213a breaks, so as to achieve rapid pressure relief of the battery cell 20.

[0310] According to some embodiments of the present application, see Figure 5 and Figure 8 As shown, along the thickness direction Z of the first wall, the projection of the first groove 213 does not overlap with the projection of the second groove 214. That is, the first groove 213 and the second groove 214 do not contact each other, so that the first groove 213 and the second groove 214 are not connected, and the first groove 213 and the second groove 214 may be spaced apart in the first direction X, or may be spaced apart in the thickness direction Z of the first wall.

[0311] In this embodiment, the first groove 213 and the second groove 214 are arranged to have non-overlapping projections in the thickness direction Z of the first wall, so that the first groove 213 and the second groove 214 do not contact each other. On the one hand, the mutual influence between the first groove 213 and the second groove 214 during the processing can be reduced. On the other hand, the phenomenon that the first wall 211 cracks along the second groove 214 when the first wall 211 cracks along the first groove 213 for pressure relief can be reduced, and the stress influence between the area of ​​the first wall 211 where the first groove 213 is set and the area of ​​the first wall 211 where the second groove 214 is set can be reduced.

[0312] In some embodiments, see Figure 5 and Figure 8 As shown, along the first direction X, the second groove 214 is spaced apart from the first groove 213 .

[0313] Exemplarily, the second groove 214 and the second groove section 213 b and the third groove section 213 c are spaced apart in the first direction X, and the second groove 214 and the first groove section 213 a are parallel to each other.

[0314] In this embodiment, the second groove 214 is arranged to be spaced apart from the second groove section 213b and the third groove section 213c of the first groove 213 in the first direction X, so that the predetermined pressure relief area 2113 defined by the first groove section 213a, the second groove section 213b and the third groove section 213c can be flipped around the area of ​​the first wall 211 where the second groove 214 is arranged when being opened, and the flipping angle of the predetermined pressure relief area 2113 after being opened can be increased, so as to increase the pressure relief area of ​​the battery cell 20.

[0315] In some embodiments, the first groove 213 is stamped and formed on the first wall 211 .

[0316] It should be noted that if the first groove 213 is a primary groove structure, when the first groove 213 is formed on the first wall 211, the first wall 211 can be punched once to punch out the first groove 213 on the first wall 211; if the first groove 213 is a multi-stage groove structure, when the first groove 213 is formed on the first wall 211, the first wall 211 can be punched multiple times to punch out a primary groove each time, and the first groove 213 is finally formed after multiple stampings.

[0317] In this embodiment, the first groove 213 is formed by stamping the first wall 211 , so that the forming method of the first groove 213 is simple, which is beneficial to reducing the production cost of the battery cell 20 .

[0318] In some embodiments, the second groove 214 is stamped and formed on the first wall 211 .

[0319] In this embodiment, the second groove 214 is formed by stamping the first wall 211 , so that the second groove 214 is formed in a simple manner, which is beneficial to reducing the production cost of the battery cell 20 .

[0320] According to some embodiments of the present application, see Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the housing 21 may include a shell 215 and an end cap 216 . The shell 215 has an interior forming a receiving cavity with an opening 2151 for receiving the electrode assembly 22 . The end cap 216 closes the opening 2151 . The shell 215 includes a first wall 211 .

[0321] The shell 215 includes an integrally formed side wall and a bottom wall, that is, the shell 215 is manufactured by an integral molding process, such as an integral molding process such as stamping, casting or extrusion molding, that is, the side wall and the bottom wall of the shell 215 are an integral structure.

[0322] The housing 215 includes a first wall 211, that is, the first wall 211 is a wall of the housing 215. Figure 5 and Figure 6 In the embodiment, the first wall 211 is the bottom wall of the housing 215 disposed opposite to the end cover 216 in the thickness direction Z of the first wall, and correspondingly, the second wall 212 is one of the side walls of the housing 215, that is, the first groove 213 and the second groove 214 are both disposed on the bottom wall of the housing 215. Of course, in other embodiments, the first wall 211 may also be the side wall of the housing 215.

[0323] In the present embodiment, by setting the first wall 211 of the outer shell 21 as a wall of the shell 215, the battery cell 20 adopting such a structure can make the area of ​​the outer shell 21 where the first groove 213 and the second groove 214 are provided away from the end cover 216, thereby effectively alleviating the phenomenon that the stress generated by the connection between the end cover 216 and the shell 215 acts on the area where the first groove 213 and the second groove 214 are provided, so as to reduce the influence on the area where the first wall 211 is provided with the first groove 213 and the second groove 214, and further help to reduce the risk of cracking or reduction in structural strength of the area where the first wall 211 is provided with the first groove 213 and the second groove 214 under the pulling action of stress, so as to improve the service life and reliability of the battery cell 20.

[0324] It should be noted that the structure of the battery cell 20 is not limited thereto. In some embodiments, the battery cell 20 may also be other structures. For example, the housing 21 may include a shell 215 and an end cover 216. The interior of the shell 215 forms a receiving cavity with an opening 2151, and the receiving cavity is used to receive the electrode assembly 22. The end cover 216 closes the opening 2151, and the end cover 216 is a first wall 211. In other words, the second groove 214 and the first groove 213 are both provided on the end cover 216 of the housing 21, and correspondingly, the second wall 212 is one of the side walls of the housing 215.

[0325] In this embodiment, by setting the first wall 211 of the outer shell 21 as the end cover 216 of the outer shell 21 for closing the opening 2151, the battery cell 20 adopting this structure is convenient for setting the first groove 213 and the second groove 214 on the end cover 216, which is beneficial to reduce the manufacturing difficulty of the battery cell 20 and improve the production efficiency of the battery cell 20.

[0326] It should be noted that the structure of the battery cell 20 can be various. In some embodiments, the outer shell 21 may include a shell 215 and two end covers 216. The shell 215 has a housing cavity formed inside, which is used to accommodate the electrode assembly 22. Openings 2151 are formed at opposite ends of the shell 215, and the two openings 2151 are connected to the housing cavity. The two end covers 216 respectively close the two openings 2151, and one of the two end covers 216 is a first wall 211.

[0327] In this embodiment, the shell 215 of the outer shell 21 is provided with openings 2151 at both opposite ends, and the two end covers 216 respectively close the two openings 2151, and the first wall 211 is one of the two end covers 216. The battery cell 20 adopting this structure is convenient for assembling the battery cell 20 from both ends of the shell 215, which is beneficial to reducing the manufacturing difficulty and assembly difficulty of the battery cell 20, and is convenient to set the first groove 213 and the second groove 214 on the end cover 216, which is beneficial to reducing the manufacturing difficulty of the battery cell 20 and improving the production efficiency of the battery cell 20.

[0328] Of course, the structure of the battery cell 20 is not limited thereto. In the embodiment where the outer shell 21 includes a shell 215 and two end caps 216, the shell 215 may include a first wall 211, that is, the first wall 211 is a wall of the shell 215. By setting the first wall 211 of the outer shell 21 as a wall of the shell 215, the battery cell 20 with such a structure can make the area of ​​the outer shell 21 where the first groove 213 and the second groove 214 are provided away from the end cap 216, so as to effectively alleviate the phenomenon that the stress generated by the connection between the end cap 216 and the shell 215 acts on the area where the first groove 213 and the second groove 214 are provided, so as to reduce the influence on the area where the first groove 213 and the second groove 214 are provided on the first wall 211, thereby facilitating the risk of cracking or structural strength reduction in the area where the first groove 213 and the second groove 214 are provided on the first wall 211 under the pulling action of stress, so as to improve the service life and reliability of the battery cell 20.

[0329] According to some embodiments of the present application, the material of the first wall 211 includes steel.

[0330] Exemplarily, the material of the first wall 211 may be carbon steel, alloy steel, stainless steel or the like.

[0331] It should be noted that the material of the first wall 211 includes steel. If the first wall 211 is the end cover 216 of the outer shell 21, the material of the end cover 216 is steel; if the first wall 211 is a wall in the shell 215, the material of the shell 215 is steel.

[0332] In this embodiment, by setting the material of the first wall 211 to steel, due to the high strength of steel, the first wall 211 made of steel has better strength, so that when the bursting pressure of the battery cell 20 is constant, the first wall 211 can be made thinner, which is beneficial to saving the space occupied by the first wall 211.

[0333] In some embodiments, the steel material is carbon steel or stainless steel.

[0334] Illustratively, the carbon steel may be low carbon steel, medium carbon steel or high carbon steel.

[0335] In this embodiment, carbon steel or stainless steel is used as the material of the first wall 211 , which has low cost and is easy to manufacture.

[0336] According to some embodiments of the present application, the material of the first wall 211 includes aluminum alloy.

[0337] It should be noted that the material of the first wall 211 includes aluminum alloy. If the first wall 211 is the end cover 216 of the outer shell 21, the material of the end cover 216 is aluminum alloy; if the first wall 211 is a wall in the shell 215, the material of the shell 215 is aluminum alloy.

[0338] In this embodiment, by setting the material of the first wall 211 to aluminum alloy, due to the characteristics of aluminum alloy being light weight and good ductility, it is easier to process the first groove 213 and the second groove 214 on the first wall 211, which helps to reduce the manufacturing difficulty of the first groove 213 and the second groove 214.

[0339] In some embodiments, the aluminum alloy includes the following components in 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%.

[0340] In the present embodiment, the aluminum alloy belongs to the third series aluminum. The aluminum alloy has lower hardness and better forming ability, which can further reduce the processing difficulty of the first groove 213 and the second groove 214 and improve the processing accuracy of the first groove 213 and the second groove 214, thereby facilitating improving the pressure relief consistency of the battery cell 20.

[0341] In some embodiments, the aluminum alloy includes the following components in percentage by mass: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single element components ≤ 0.05%, and the total composition of other elements ≤ 0.15%.

[0342] In this embodiment, the aluminum alloy belongs to the fifth series aluminum. The first wall 211 made of the aluminum alloy has higher hardness and greater strength, so that the first wall 211 has good anti-destruction ability.

[0343] According to some embodiments of the present application, the present application further provides a battery 100, and the battery 100 includes a battery cell 20 of any of the above schemes.

[0344] Among them, see Figure 2 As shown, the battery 100 may further include a housing 10 , in which the battery cells 20 are accommodated.

[0345] In some embodiments, the box body 10 may include a first box body 11 and a second box body 12 . The first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cells 20 .

[0346] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure. The first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define an assembly space; the first box body 11 and the second box body 12 can also be hollow structures both with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0347] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder or a cuboid. Figure 2 In the embodiment, the box body 10 is a rectangular parallelepiped structure.

[0348] Optionally, the number of battery cells 20 disposed in the box body 10 may be one or more. Figure 2 In the embodiment, a plurality of battery cells 20 are arranged in the box 10 of the battery 100, and the plurality of battery cells 20 can be connected in series, in parallel or in a mixed connection. The mixed connection means that the plurality of battery cells 20 are both connected in series and in parallel. The plurality of battery cells 20 can be directly connected in series, in parallel or in a mixed connection, and then the whole formed by the plurality of battery cells 20 is accommodated in the box 10; of course, the battery 100 can also be a battery module formed by first connecting the plurality of battery cells 20 in series, in parallel or in a mixed connection, and then the plurality of battery modules are connected in series, in parallel or in a mixed connection to form a whole, and then accommodated in the box 10.

[0349] The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component, which connects the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0350] It should be noted that, in some embodiments, the battery 100 may not be provided with a box 10, and the battery 100 includes a plurality of battery cells 20, and the battery 100 composed of a plurality of battery cells 20 may be directly assembled on an electrical device to provide electrical energy to the electrical device through the plurality of battery cells 20. In other words, the box 10 may be used as a part of the electrical device. Taking the vehicle 1000 as an example of the electrical device, the box 10 may be used as a part of the chassis structure of the vehicle 1000, for example, a part of the box 10 may become at least a part of the floor of the vehicle 1000, or a part of the box 10 may become at least a part of the crossbeam and longitudinal beam of the vehicle 1000.

[0351] According to some embodiments of the present application, the present application further provides an electrical device, which includes a battery cell 20 according to any of the above schemes, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0352] The electrical device may be any of the aforementioned devices or systems using the battery cell 20 .

[0353] According to some embodiments of the present application, see Figures 3 to 7As shown, the present application provides a battery cell 20, which includes a shell 21 and an electrode assembly 22. The shell 21 is a rectangular parallelepiped structure, and the shell 21 includes a shell 215 and an end cover 216. The shell 215 forms a receiving cavity with an opening 2151 inside, and the electrode assembly 22 is received in the receiving cavity, and the end cover 216 closes the opening 2151. The shell 215 includes a bottom wall and a side wall surrounding the bottom wall, and one end of the side wall in the thickness direction Z of the first wall is connected to the bottom wall, and the other end is surrounded to form an opening 2151. The bottom wall of the shell 215 is a first wall 211, and the two walls of the side wall of the shell 215 connected to both sides of the first wall 211 in the first direction X are second walls 212, the width direction of the first wall 211 and the thickness direction of the second wall 212 are both the first direction X, the length direction of the first wall 211 is the second direction Y, and the first direction X, the second direction Y and the thickness direction Z of the first wall are perpendicular to each other. The first wall 211 is provided with a first groove 213. The first wall 211 is configured to be able to split along at least part of the first groove 213 when the battery cell 20 is depressurized to release the internal pressure of the battery cell 20. The first groove 213 includes a first groove section 213a, a second groove section 213b and a third groove section 213c. The first groove section 213a extends along the second direction Y, and the first groove section 213a is located between the two second walls 212 in the first direction X. The second groove section 213b and the third groove section 213c are connected to each other in the first direction X. The third slot sections 213c are arranged at intervals along the second direction Y and extend along the first direction X. The two ends of the first slot section 213a are respectively connected to the second slot section 213b and the third slot section 213c. The connection position of the second slot section 213b and the first slot section 213a deviates from the two ends of the second slot section 213b. The connection position of the third slot section 213c and the first slot section 213a deviates from the two ends of the third slot section 213c, so that a predetermined pressure relief area 2113 is formed on both sides of the first slot section 213a. The first wall 211 is further provided with two second grooves 214. Along the first direction X, the second wall 212 has a first outer surface 2121 facing away from the inside of the housing 21. A second groove 214 is provided between the first groove section 213a and the first outer surfaces 2121 of the two second walls 212. The second groove 214 extends along the second direction Y, and the projection of the second groove 214 in the thickness direction Z of the first wall is located between the projection of the first groove section 213a in the thickness direction Z of the first wall and the first outer surface 2121. The predetermined pressure relief area 2113 is configured to be opened and turned around the second groove 214 when the first wall 211 is cracked along the first groove 213, so as to release the internal pressure of the battery cell 20. Along the first direction X, the first groove 213 is located between the two second grooves 214, and the two second grooves 214 are spaced apart from the first groove 213.Along the first direction X, the minimum distance between the first groove section 213a and the first outer surface 2121 is L1, and the size of the battery cell 20 is L2, which satisfies 0.11≤L1 / L2≤0.44, 10mm≤L1≤44mm, 25mm≤L2≤100mm, and preferably, 0.15≤L1 / L2≤0.4. Along the thickness direction Z of the first wall, the minimum residual thickness of the first groove 213 is D1, and the minimum residual thickness of the second groove 214 is D2, which satisfies D2>D1. The first wall 211 has a first surface 2111 and a second surface 2112 opposite to each other. The first surface 2111 is the surface of the first wall 211 on the side facing away from the inside of the housing 21. The first groove 213 is arranged on the first surface 2111, and the second groove 214 is arranged on the second surface 2112. The first groove 213 is a multi-level groove arranged in sequence from the first surface 2111 to the second surface 2112. Along the thickness direction Z of the first wall, in two adjacent grooves, the first-level groove away from the first surface 2111 is arranged on the groove bottom surface of the first-level groove close to the first surface 2111. The groove arranged on the first surface 2111 among the multi-level grooves is the first-level groove 2131. The maximum groove depth of the second groove 214 is H1, and the minimum residual thickness of the first-level groove 2131 is D3, satisfying that H1≥D3.

[0354] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0355] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: A housing having a first wall and a second wall connected to each other, wherein the first wall is provided with a first groove, and the first wall is configured to be able to be split along at least a portion of the first groove when the battery cell is depressurized to release the internal pressure of the battery cell, and the second wall is located on one side of the first wall along a first direction, the first groove includes a first groove section, and the first groove section and the second wall are arranged along the first direction; The first wall is further provided with a second groove, and along the first direction, the second wall has a first outer surface facing away from the interior of the shell, and the projection of the second groove in the thickness direction of the first wall is located between the first outer surface and the projection of the first groove segment in the thickness direction of the first wall, and the first direction is perpendicular to the thickness direction of the first wall.

2. The battery cell according to claim 1, characterized in that: Along the first direction, the minimum distance L1 between the first groove section and the first outer surface is greater than or equal to 0.11 times the size L2 of the battery cell, and the minimum distance L1 between the first groove section and the first outer surface is less than or equal to 0.44 times the size L2 of the battery cell.

3. The battery cell according to claim 2, characterized in that: Along the first direction, the minimum distance L1 between the first groove section and the first outer surface is greater than or equal to 0.15 times the size L2 of the battery cell, and the minimum distance L1 between the first groove section and the first outer surface is less than or equal to 0.4 times the size L2 of the battery cell.

4. The battery cell according to claim 1, characterized in that: Along the first direction, a minimum distance between the first groove segment and the first outer surface is L1, which satisfies 10 mm ≤ L1 ≤ 44 mm.

5. The battery cell according to claim 1, characterized in that: Along the first direction, the size of the battery cell is L2, satisfying 25 mm ≤ L2 ≤ 100 mm.

6. The battery cell according to claim 1, characterized in that: Along the thickness direction of the first wall, the minimum residual thickness of the first groove is D1, and the minimum residual thickness of the second groove is D2, satisfying D2>D1.

7. The battery cell according to claim 1, characterized in that: The first wall has a first surface and a second surface opposite to each other along a thickness direction of the first wall; Wherein, the first groove is arranged on the first surface, and the second groove is arranged on the second surface.

8. The battery cell according to claim 7, characterized in that: Along the first direction, projections of the first groove and the second groove at least partially overlap.

9. The battery cell according to claim 7, characterized in that: Along the thickness direction of the first wall, a groove bottom surface of the second groove is closer to the first surface than a groove bottom surface of the first groove.

10. The battery cell according to claim 7, characterized in that: Along the thickness direction of the first wall, the maximum groove depth of the second groove is H1, and the minimum residual thickness of the first groove is D1, satisfying H1>D1.

11. The battery cell according to claim 7, characterized in that: The first groove is a multi-level groove arranged in sequence from the first surface to the second surface, and along the thickness direction of the first wall, in two adjacent levels of the grooves, the first-level groove away from the first surface is arranged on the groove bottom surface of the first-level groove close to the first surface; Among the multi-level grooves, the grooves arranged on the first surface are first-level grooves, and along the first direction, the second grooves at least partially overlap with the projection of the first-level grooves.

12. The battery cell according to claim 7, characterized in that: The first groove is a multi-level groove arranged in sequence from the first surface to the second surface, and along the thickness direction of the first wall, in two adjacent levels of the grooves, the first-level groove away from the first surface is arranged on the groove bottom surface of the first-level groove close to the first surface; Among them, the grooves in the multi-level grooves arranged on the first surface are first-level grooves, and along the thickness direction of the first wall, the bottom surface of the second groove is flush with the bottom surface of the first-level groove or the bottom surface of the second groove is closer to the first surface than the bottom surface of the first-level groove.

13. The battery cell according to claim 7, characterized in that: The first groove is a multi-level groove arranged in sequence from the first surface to the second surface, and along the thickness direction of the first wall, in two adjacent levels of the grooves, the first-level groove away from the first surface is arranged on the groove bottom surface of the first-level groove close to the first surface; Among the multi-level grooves, the grooves arranged on the first surface are first-level grooves, the maximum groove depth of the second grooves is H1, and the minimum residual thickness of the first-level grooves is D3, satisfying H1≥D3.

14. The battery cell according to claim 1, characterized in that: The first wall has a first surface and a second surface opposite to each other along a thickness direction of the first wall; Wherein, the first groove and the second groove are both arranged on the first surface.

15. The battery cell according to claim 14, characterized in that: The first groove is a multi-level groove arranged in sequence from the first surface to the second surface, and along the thickness direction of the first wall, in two adjacent levels of the grooves, the first-level groove away from the first surface is arranged on the groove bottom surface of the first-level groove close to the first surface; Among the multi-stage grooves, the grooves arranged on the first surface are first-stage grooves, and along the thickness direction of the first wall, the bottom surface of the first-stage groove is closer to the first surface than the bottom surface of the second groove.

16. The battery cell according to claim 14, characterized in that: The first groove is a multi-level groove arranged in sequence from the first surface to the second surface, and along the thickness direction of the first wall, in two adjacent levels of the grooves, the first-level groove away from the first surface is arranged on the groove bottom surface of the first-level groove close to the first surface; Among the multi-level grooves, the grooves arranged on the first surface are first-level grooves. Along the thickness direction of the first wall, the maximum groove depth of the second groove is H1, and the maximum groove depth of the first-level groove is H2, satisfying H1>H2.

17. The battery cell according to claim 7, characterized in that: The first surface is a surface of the first wall that faces away from the interior of the housing.

18. The battery cell according to claim 1, characterized in that: Along the first direction, the housing has two second walls arranged opposite to each other in the first direction, and the two second walls are respectively connected to two sides of the first wall; Wherein, along the first direction, the first slot section is located between two second walls, and the second groove is provided between the first slot section and the first outer surfaces of the two second walls.

19. The battery cell according to claim 1, characterized in that: The first wall is a rectangular structure, and the width direction of the first wall and the thickness direction of the second wall are both parallel to the first direction.

20. The battery cell according to claim 1, characterized in that Along the thickness direction of the first wall, two ends of the projection of the second groove in its extending direction respectively extend beyond two end portions of the projection of the first groove segment.

21. The battery cell according to claim 20, characterized in that: The second groove extends along a second direction. Along the second direction, two ends of the second groove extend out of two ends of the first groove segment respectively. The first direction, the second direction and the thickness direction of the first wall are perpendicular to each other.

22. The battery cell according to claim 1, characterized in that: The first groove also includes a second groove section, the first groove section is connected to the second groove section, the first groove section and the second groove section jointly define a predetermined pressure relief area, and the predetermined pressure relief area is configured to be opened when the first wall is cracked along at least a portion of the first groove to release the internal pressure of the battery cell.

23. The battery cell according to claim 1, characterized in that: The first groove further includes a second groove section and a third groove section, the second groove section and the third groove section are arranged opposite to each other along a second direction, and the second direction is perpendicular to the first direction; The first groove section connects the second groove section and the third groove section, and the first groove section, the second groove section and the third groove section jointly define a predetermined pressure relief area, and the predetermined pressure relief area is configured to be opened and flipped around the second groove when the first wall is cracked along the first groove to release the internal pressure of the battery cell.

24. The battery cell according to claim 23, characterized in that: The connection position between the second slot section and the first slot section deviates from the two ends of the second slot section, and the connection position between the third slot section and the first slot section deviates from the two ends of the third slot section, so that the predetermined pressure relief area is formed on both sides of the first slot section.

25. The battery cell according to claim 24, characterized in that: The first slot segment, the second slot segment and the third slot segment all extend along a straight line trajectory, and the second slot segment and the third slot segment are both perpendicular to the first slot segment.

26. The battery cell according to claim 23, characterized in that: The first slot segment, the second slot segment and the third slot segment all extend along an arc trajectory.

27. The battery cell according to claim 23, characterized in that: The first groove further includes a fourth groove section, the fourth groove section is located between the second groove section and the third groove section, and the fourth groove section is connected to the first groove section.

28. The battery cell according to claim 1, characterized in that: Along the thickness direction of the first wall, a projection of the first groove does not overlap with a projection of the second groove.

29. The battery cell according to claim 28, characterized in that: Along the first direction, the second groove is spaced apart from the first groove.

30. The battery cell according to any one of claims 1 to 29, characterized in that: The housing comprises: A housing having an opening formed therein, wherein the housing is used to accommodate the electrode assembly; an end cap for closing the opening; wherein the housing includes the first wall; or The end cover is the first wall.

31. The battery cell according to any one of claims 1 to 29, characterized in that: The housing comprises: A shell having a receiving cavity formed therein, the receiving cavity being used to receive the electrode assembly, openings being formed at opposite ends of the shell, and both openings being in communication with the receiving cavity; Two end covers, respectively closing the two openings; Wherein, one of the two end covers is the first wall; or The housing includes the first wall.

32. A battery, characterized in that: Comprising the battery cell according to any one of claims 1-31.

33. An electrical device, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 31, wherein the battery cell is used to provide electrical energy.

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