Battery cell, battery, and electrical device

Abstract

The present application relates to the technical field of batteries, and provides a battery cell, a battery, and an electrical device. The battery cell comprises a housing; the housing has a first wall and second walls which are connected to 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 during pressure relief of the battery cell, so as to relieve internal pressure of the battery cell; the second walls are located on the sides of the first wall in a first direction; the first groove comprises a first groove section; and the first groove section and the second walls are arranged in the first direction. The first wall is further provided with second grooves; in the first direction, the second walls have first outer surfaces facing away from the interior of the housing; the projection of each second groove in the thickness direction of the first wall is located between the projection of the corresponding first outer surface in the thickness direction of the first wall and the projection of the first groove section in the thickness direction of the first wall, so that the second grooves can absorb excess materials extruded from the first groove section during the forming of the first groove section, thereby relieving local protrusion of the battery cell or the decrease in the flatness of the first wall.

Description

Battery cells, batteries and electrical devices 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 experienced rapid development. In the electric vehicle sector, 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. As a core component of new energy vehicles, batteries have high requirements in terms of reliability and service life.

[0003] In battery technology, to ensure the safety of battery cells, a pressure relief structure is typically integrated into the outer shell of the battery cell to release internal pressure. This structure activates to release pressure when the internal pressure or temperature of the battery cell reaches a threshold. However, the addition of a pressure relief structure to existing battery cells often results in poor overall dimensional consistency within the outer shell, hindering the production quality of the battery cells.

[0004] Summary of the Invention

[0005] 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.

[0006] 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 crack 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 further 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.

[0007] In the above technical solution, the shell has a first wall and a second wall connected to each other, and a first groove is provided on the first wall, so that the first wall can crack 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 where the first groove section is provided on the first wall 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, 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 and pressure relief of the battery cell during use, which is beneficial to improving the reliability and service life of the battery cell.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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 absorption effect of the second groove on 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, thereby facilitating further improving the flatness of the first wall and further improving the consistency of the size of the battery cell in the first direction.

[0012] In some embodiments, along the first direction, a minimum distance between the first groove segment and the first outer surface is L1, satisfying 10 mm ≤ L1 ≤ 44 mm.

[0013] In the above technical solution, by setting the minimum distance between the first groove segment and the first outer surface in the first direction to be greater than or equal to 10 mm, the size of the area between the first groove segment and the first outer surface in the first direction can be increased, thereby reducing the difficulty of providing the second groove between the first groove segment and the first outer surface and alleviating the inability to provide the second groove between the first groove segment and the first outer surface, thereby reducing the difficulty of manufacturing the battery cell. Furthermore, the problem of the second groove being unable to absorb excess material extruded during the molding process of the first groove segment due to a small distance between the first groove segment and the first outer surface can be alleviated. This can also reduce the local increase in size of the battery cell or poor flatness of the first wall due to localized material extrusion during the machining of the first groove segment, thereby effectively improving the dimensional consistency of the housing. By setting the minimum distance between the first groove segment and the first outer surface in the first direction to be less than or equal to 44 mm, the problem of the area between the first groove segment and the first outer surface being excessively large in the first direction, resulting in wasted space or over-machining of the second groove, can be reduced, thereby reducing the manufacturing cost of the battery cell.

[0014] In some embodiments, along the first direction, the size of the battery cell is L2, which satisfies 25 mm ≤ L2 ≤ 100 mm.

[0015] 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 accommodated in the housing can be increased, which is beneficial to improving the energy density of the battery cell. On the other hand, it can alleviate the difficulty in manufacturing the battery cell due to the battery cell being too small in the first direction, thereby reducing the difficulty in manufacturing the battery cell and thus 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 difficulty in subsequent assembly of the battery cell due to the battery cell being too large in the first direction can be alleviated, and the difficulty in manufacturing the battery cell can be reduced.

[0016] 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.

[0017] 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 is conducive to alleviating 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.

[0018] In some embodiments, along a 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.

[0019] 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 process.

[0020] In some embodiments, along the first direction, the first groove overlaps at least partially with a projection of the second groove.

[0021] In the above technical solution, by arranging the projections of the first groove and the second groove in the first direction to overlap at least part of each other, the second groove and the first groove segment of the first groove have 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 shell; 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, thereby enhancing 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 provided is deformed or damaged when the battery cell is subjected to internal and external impact forces.

[0022] In some embodiments, along the thickness direction of the first wall, a bottom surface of the second groove is closer to the first surface than a bottom surface of the first groove.

[0023] In the above technical solution, the bottom surface of the second groove is closer to the first surface in the thickness direction of the first wall than the bottom surface of the first groove, so that the second groove and the first groove section of the first groove have overlapping areas in the first direction, thereby, on the one hand, improving the absorption effect of the second groove on the excess material squeezed out of the first groove section 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 section of the first wall of the shell; on the other hand, it can improve 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 improve the buffering effect of the second groove between the first groove section and the second wall, thereby effectively reducing 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.

[0024] 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.

[0025] 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, thereby, on the one hand, being able to improve the absorption effect of the second groove on the residual 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; on the other hand, being able to improve 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, thereby improving 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 provided is deformed or damaged when the battery cell is subjected to internal and external impact forces.

[0026] 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 in the multi-level groove 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.

[0027] In the above technical solution, by setting the first groove as a multi-level groove arranged along the thickness direction of the first wall, and setting the second groove and the first-level groove of the first groove to at least partially overlap in their projection in the first direction, the second groove can cover the other multi-level grooves arranged on the bottom surface of the first-level 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 forming process of the multi-level groove can be improved, so as to further 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 of material during the processing of the first groove section 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 phenomenon that the area of ​​the first wall where the first groove is provided with the first groove is deformed or damaged when the battery cell is subjected to internal and external impact forces.

[0028] 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 of the multi-level groove 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.

[0029] In the above technical solution, by setting the first groove as a multi-level groove arranged along the thickness direction of the first wall, and setting the groove bottom surface of the second groove in the thickness direction of the first wall to be flush with the groove bottom surface of the first-level groove or closer to the first surface than the groove bottom surface of the first-level groove, the second groove can cover the other multi-level grooves arranged on the groove bottom surface of the first-level groove in the first groove section in the first direction, thereby, on the one hand, improving the absorption effect of the second groove on the excess material squeezed out of the first groove section during the forming process of the multi-level groove, so as to further 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; on the other hand, it can further improve 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, thereby further improving the buffering effect of the second groove between the first groove section and the second wall, thereby further reducing the phenomenon that the area of ​​the first wall where the first groove is provided with the first groove is deformed or damaged when the battery cell is subjected to internal and external impact forces.

[0030] 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 in the multi-level groove 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 H1≥D3.

[0031] In the above technical solution, by setting the first groove as a multi-level 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-level groove in the multi-level groove, the second groove can cover the other multi-level grooves arranged on the groove bottom surface of the first-level 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 forming process of the multi-level groove can be improved, so as to further 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 of material during the processing of 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 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.

[0032] In some embodiments, along a 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 provided on the first surface.

[0033] In the above technical solution, by arranging the first groove and the second groove on the first surface of the first wall, 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 achieve mutual spacing and avoidance between the first groove and the second groove during processing, which is beneficial to reducing 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 achieved without flipping the first wall, which is beneficial to optimizing the production rhythm of the battery cell.

[0034] 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.

[0035] In the above technical solution, the bottom surface of the first groove is closer to the first surface than the bottom surface of the second groove in the thickness direction of the first wall, so that the second groove is a structure of the first groove covering the first groove segment in the first direction. On the one hand, the absorption effect of the second groove on the excess material squeezed out of the first groove segment during the processing of 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 during the processing of the first groove segment 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 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.

[0036] 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 maximum groove depth of the second groove is H1, and the maximum groove depth of the first-level groove is H2, satisfying H1>H2.

[0037] 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-level groove in the multi-level groove of the first groove, the second groove is made to be a structure of the first-level groove covering the first groove segment 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 segment during the processing of the multi-level groove 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 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.

[0038] In some embodiments, the first surface is a surface of the first wall facing away from the interior of the housing.

[0039] In the above technical solution, by setting the first surface of the first wall as the surface of the first wall on the side facing away from the interior of the shell, the first groove is set on the side of the first wall facing 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 processing difficulty of the first groove and improving the production efficiency of the battery cell.

[0040] 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 the 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.

[0041] In the above technical solution, the shell has two second walls located on both sides of the first wall in the first direction, and a second groove is provided 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 local size of the battery cell increases or the flatness of the first wall is poor due to local extrusion of material during the processing of the first groove section of the shell. 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 provided when the battery cell is subjected to internal and external impact forces.

[0042] 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.

[0043] In the above technical solution, the first wall is a rectangular structure, so that the outer shell of the battery cell is a cuboid 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, thereby facilitating improving the buffering and protection effect of the second groove on the first groove section.

[0044] 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.

[0045] 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 beyond the two ends of the projection of the first groove segment, the second groove is made to have 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, thereby improving the absorption effect of the second groove on the residual material extruded during the molding process of the first groove segment, and improving 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.

[0046] 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.

[0047] 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 processing difficulty of the second groove, and it is convenient to set the second groove as a structure in which the two ends in the second direction respectively exceed the two ends of the first groove section, so as to reduce the manufacturing difficulty of the battery cell, and thus help improve the production efficiency of the battery cell.

[0048] In some embodiments, the first groove further includes a second groove section, the first groove section is connected to the second groove section, and 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.

[0049] 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, it can increase the pressure relief area of ​​the battery cell to increase the pressure relief rate of the battery cell. On the other hand, it makes the position where the first groove section and the second groove section are connected to each other weaker, which is easier to crack and open the predetermined pressure relief area to release the internal pressure of the battery cell.

[0050] In some embodiments, the first groove further includes a second groove section and a third groove section, and 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; wherein, 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.

[0051] In the above technical solution, the first groove further includes a third groove section disposed on the second side opposite the second groove section, and the first groove section connects the second and third groove sections, so that when the battery cell releases pressure, the first wall can rupture along the first, second, and third groove sections to open a predetermined pressure relief area to release the internal pressure of the battery cell. This structure of the first groove makes the intersection of the first and second groove sections and the connection between the first and third groove sections weaker, making it easier to rupture and open the predetermined pressure relief area for pressure relief, further increasing the pressure relief area and pressure relief rate of the battery cell. Furthermore, because the second groove and the first groove section are arranged along the first direction, the predetermined pressure relief area defined by the first, second, and third groove sections can be rotated about the second groove as the axis when opened, which helps to improve the effectiveness and extent of the opening of the predetermined pressure relief area, thereby further enhancing the pressure relief effect of the battery cell.

[0052] In some embodiments, the connection position of the second trough section and the first trough section deviates from the two ends of the second trough section, and the connection position of the third trough section and the first trough section deviates from the two ends of the third trough section, so that the predetermined pressure relief area is formed on both sides of the first trough section.

[0053] In the above technical solution, by setting the connection position between the second groove segment and the first groove segment to be located between the two ends of the second groove segment, and setting the connection position between the third groove segment and the first groove segment to be located between the two ends of the third groove segment, so that the first groove segment, the second groove segment and the third groove segment form a structure similar to an "H" shape, so that predetermined pressure relief areas can be formed on both sides of the first groove segment of the first groove, and the two predetermined pressure relief areas can be opened in a split manner to relieve pressure 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.

[0054] In some embodiments, the first slot segment, the second slot segment, and the third slot segment all extend along a straight line, and the second slot segment and the third slot segment are both perpendicular to the first slot segment.

[0055] 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, thereby reducing 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.

[0056] In some embodiments, the first slot segment, the second slot segment, and the third slot segment all extend along an arc trajectory.

[0057] 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.

[0058] 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.

[0059] In the above technical solution, the first groove is further 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.

[0060] 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.

[0061] In the above technical solution, by setting the first groove and the second groove to a structure in which the projections in the thickness direction of the first wall do not overlap with each other, 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 process can be reduced, and 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.

[0062] In some embodiments, along the first direction, the second groove is spaced apart from the first groove.

[0063] In the above technical solution, by arranging the second groove to be spaced apart from the second groove section and the third groove section of the first groove in the first direction, 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 provided when being opened, and the flipping angle of the predetermined pressure relief area after being opened can be increased, thereby increasing the pressure relief area of ​​the battery cell.

[0064] In some embodiments, the first groove is stamped and formed on the first wall.

[0065] In the above technical solution, the first groove is stamped and formed on the first wall, so that the forming method of the first groove is simple, which is conducive to reducing the production cost of the battery cell.

[0066] In some embodiments, the second groove is stamped and formed on the first wall.

[0067] In the above technical solution, the second groove is stamped and formed on the first wall, so that the forming method of the second groove is simple, which is conducive to reducing the production cost of the battery cell.

[0068] In some embodiments, the housing includes a shell and an end cover; a housing having an opening is formed inside the shell, and the housing 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.

[0069] In the above technical solution, by configuring the first wall of the housing as a wall of the shell, a battery cell adopting this structure can position the area of ​​the housing where the first and second grooves are provided away from the end cap, thereby effectively alleviating the stress generated by the connection between the end cap and the shell from acting on the area where the first and second grooves are provided, thereby reducing the impact on the area where the first and second grooves are provided on the first wall, thereby facilitating the reduction of the risk of cracking or structural strength degradation in the area where the first and second grooves are provided under the pulling effect of stress, thereby improving the service life and reliability of the battery cell. By configuring the first wall of the housing as an end cap for closing the opening of the housing, a battery cell adopting this structure facilitates the provision of the first and second grooves on the end cap, thereby reducing the manufacturing difficulty of the battery cell and improving the production efficiency of the battery cell.

[0070] 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.

[0071] In the above technical solution, the shell of the housing is provided with openings at opposite ends, and two end caps respectively close the two openings. The first wall is one of the two end caps. Battery cells adopting this structure facilitate assembly of the battery cells from both ends of the housing, thereby reducing the difficulty of manufacturing and assembling the battery cells. It also facilitates the provision of the first and second grooves on the end caps, thereby reducing the difficulty of manufacturing the battery cells and improving the production efficiency of the battery cells. By providing the first wall of the housing as a wall of the housing, battery cells adopting this structure can position the areas of the housing where the first and second grooves are provided away from the end caps, thereby effectively alleviating the stress generated by the connection between the end cap and the housing from acting on the areas where the first and second grooves are provided, thereby reducing the impact on the areas where the first and second grooves are provided on the first wall. This further reduces the risk of cracking or structural strength reduction in the areas where the first and second grooves are provided on the first wall due to the tensile stress, thereby improving the service life and reliability of the battery cells.

[0072] In some embodiments, the material of the first wall includes steel.

[0073] In the above technical solution, by setting the material of the first wall to steel, due to the high strength of steel, the first wall made of steel has better strength, so that when the bursting pressure of the battery cell is constant, the first wall can be made thinner, which is beneficial to saving the space occupied by the first wall.

[0074] In some embodiments, the steel is made of carbon steel or stainless steel.

[0075] In the above technical solution, carbon steel or stainless steel is used as the material of the first wall, which is low in cost and easy to manufacture.

[0076] In some embodiments, the material of the first wall includes aluminum alloy.

[0077] In the above technical solution, by setting the material of the first wall to aluminum alloy, due to the characteristics of aluminum alloy being light weight and good ductility, it is easier to process the first groove and the second groove on the first wall, which is conducive to reducing the manufacturing difficulty of the first groove and the second groove.

[0078] In some embodiments, the aluminum alloy includes the following components in percentage by mass: 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%.

[0079] In the above technical solution, the aluminum alloy used has lower hardness and better forming ability, which can further reduce the processing difficulty of the first groove and the second groove, and can improve the processing accuracy of the first groove and the second groove, thereby facilitating improving the pressure relief consistency of the battery cell.

[0080] 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%.

[0081] In the above technical solution, the first wall made of the aluminum alloy has higher hardness and greater strength, so that the first wall has good anti-destruction ability.

[0082] In a second aspect, an embodiment of the present application further provides a battery comprising the above-mentioned battery cell.

[0083] 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

[0084] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. 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 relevant drawings can be obtained based on these drawings without creative work.

[0085] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0086] FIG2 is an exploded view of the structure of a battery provided in some embodiments of the present application;

[0087] FIG3 is a schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0088] FIG4 is an exploded view of the structure of a battery cell provided in some embodiments of the present application;

[0089] FIG5 is a bottom view of a housing of a battery cell provided in some embodiments of the present application;

[0090] FIG6 is a partial cross-sectional view of a housing of a battery cell provided in some embodiments of the present application;

[0091] FIG7 is a partial enlarged view of the portion A of the housing shown in FIG6 ;

[0092] FIG8 is a bottom view of a housing of a battery cell provided in some other embodiments of the present application;

[0093] FIG9 is a partial cross-sectional view of a housing of a battery cell provided in some other embodiments of the present application;

[0094] FIG10 is a bottom view of a housing of a battery cell provided in some further embodiments of the present application;

[0095] FIG11 is a bottom view of a housing of a battery cell provided in some other embodiments of the present application;

[0096] FIG12 is a bottom view of the outer shell of a battery cell provided in some other embodiments of the present application.

[0097] Icon: 1000-vehicle; 100-battery; 10-housing; 11-first housing; 12-second housing; 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

[0098] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0099] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" 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-secondary relationship.

[0100] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0101] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0102] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0103] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0104] The term "plurality" used in this application refers to two or more (including two).

[0105] 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.

[0106] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0107] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0108] In some embodiments, the positive electrode may be a positive electrode sheet, which 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.

[0109] 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 provided on either or both of the two facing surfaces of the positive electrode current collector.

[0110] 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 layer 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.).

[0111] 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 battery positive electrode active materials may also be used. These positive electrode active materials may 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 NCM622 ), 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 0.05 O2) and at least one of its modified compounds, etc.

[0112] In some embodiments, a positive electrode may utilize a metal foam. The metal foam may include nickel foam, copper foam, aluminum foam, alloy foam, or the like. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not include a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled or / and deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0113] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0114] As an example, the negative electrode current collector may be a metal foil, a metal foam, 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 metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, etc. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (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.).

[0115] 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.

[0116] 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 provided on either or both of the two facing surfaces of the negative electrode current collector.

[0117] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well 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.

[0118] 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.

[0119] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0120] In some embodiments, the separator is a separator membrane. There are many types of separator membranes, and any known separator membrane with a porous structure having good chemical stability and mechanical stability can be selected.

[0121] As an example, the separator can be made of at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. In the case of a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0122] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0123] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0124] 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 bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0125] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl 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.

[0126] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0127] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0128] 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, or the like.

[0129] 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.

[0130] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0131] 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.

[0132] In some embodiments, the electrode assembly is a laminate structure.

[0133] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0134] 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.

[0135] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0136] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0137] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0138] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0139] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0140] In some embodiments, a 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 (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0141] As an example, the battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include but are not limited to square-shell, blade-shaped, and polygonal batteries, such as hexagonal batteries.

[0142] 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.

[0143] 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.

[0144] 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 housed in the case.

[0145] 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.

[0146] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0147] Batteries, with their outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient, are a vital component of today's new energy development. The development of battery technology requires simultaneous consideration of multiple design factors, including performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge rate. Furthermore, battery safety must also be considered.

[0148] In battery technology, for general battery cells, in order to ensure the safety of battery cells, a pressure relief structure is usually provided on the battery cells to release the internal pressure of the battery cells 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 punched 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 punching 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 an increase in local size, 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 activate pressure relief prematurely during use, which is not conducive to improving the service life and reliability of the battery cells.

[0149] Based on the above considerations, in order to address the issue of low production quality of battery cells, an embodiment of the present application provides a battery cell, comprising a housing 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 rupture 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 segment, the first groove segment and the second wall being arranged along the first direction. The first wall is further provided with a second groove, the second wall having a first outer surface facing away from the interior of the housing along the first direction, the projection of the second groove in the thickness direction of the first wall being located between the first outer surface and the projection of the first groove segment in the thickness direction of the first wall, the first direction being perpendicular to the thickness direction of the first wall.

[0150] In a battery cell of this structure, the shell has a first wall and a second wall connected to each other, and a first groove is provided on the first wall, so that the first wall can crack 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 problems 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 and pressure relief of the battery cell during use, which is beneficial to improving the reliability and service life of the battery cell.

[0151] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and batteries disclosed in this application can be used to construct such electrical devices. This can help alleviate the problem of poor dimensional consistency of the battery cell housings, thereby improving the production quality of the battery cells.

[0152] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. 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. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0153] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device according to an embodiment of the present application.

[0154] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000. The battery 100 can be arranged 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 can be used to power the vehicle 1000. For example, the battery 100 can be used as an operating power source or a power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0155] In some embodiments of the present application, the battery 100 can not only serve as the operating power source or usage power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0156] 2 and 3 , FIG2 is an exploded view of a battery 100 according to some embodiments of the present invention, and FIG3 is a schematic diagram of a battery cell 20 according to some embodiments of the present invention. The battery 100 includes a housing 10 and a battery cell 20 , wherein the battery cell 20 is accommodated in the housing 10 .

[0157] The housing 10 is used to provide assembly space for the battery cells 20 and can adopt a variety of structures. In some embodiments, the housing 10 can include a first housing body 11 and a second housing body 12. The first housing body 11 and the second housing body 12 overlap each other, and the first housing body 11 and the second housing body 12 jointly define an assembly space for accommodating the battery cells 20. The second housing body 12 can be a hollow structure with one end open, and the first housing body 11 can be a plate-like structure. The first housing body 11 overlaps the open side of the second housing body 12, so that the first housing body 11 and the second housing body 12 jointly define the assembly space. The first housing body 11 and the second housing body 12 can also be hollow structures with one end open, with the open side of the first housing body 11 overlapping the open side of the second housing body 12.

[0158] 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, etc. For example, in FIG2 , the box body 10 is in the shape of a cuboid.

[0159] In the battery 100, there can be one or more battery cells 20 disposed within the housing 10. When there are multiple battery cells 20 disposed within the housing 10, the multiple battery cells 20 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel configurations within the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure formed by the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 100 can be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid configuration to form a battery module, which is then further connected in series, in parallel, or in a hybrid configuration to form a single structure, which is then housed within the housing 10.

[0160] 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 multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20 .

[0161] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be a rectangular parallelepiped, a cylinder, a prism, or other shapes. For example, in FIG3 , the battery cell 20 is a rectangular parallelepiped.

[0162] According to some embodiments of the present application, referring to FIG3 and further referring to FIG4, FIG5, and FIG6, FIG4 is an exploded view of the structure of a battery cell 20 provided in some embodiments of the present application, FIG5 is a bottom view of the housing 21 of the battery cell 20 provided in some embodiments of the present application, and FIG6 is a partial cross-sectional view of the housing 21 of the battery cell 20 provided in some embodiments of the present application. The present application provides a battery cell 20, which includes a housing 21 having 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 rupture along at least a portion 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. 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.

[0163] 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 .

[0164] Optionally, the first groove 213 can be arranged on the side of the first wall 211 facing the interior of the shell 21, or can be arranged on the side of the first wall 211 facing away from the interior of the shell 21. For example, in Figures 5 and 6, the first groove 213 is arranged on the side of the first wall 211 facing away from the interior of the shell 21, that is, the first groove 213 is arranged on the surface of the side of the first wall 211 facing away from the interior of the shell 21.

[0165] Optionally, the second groove 214 can be arranged on the same side of the first wall 211 as the first groove 213, or can be arranged on both sides of the first wall 211. For example, in Figures 5 and 6, 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 interior of the shell 21, and the second groove 214 is arranged on the side of the first wall 211 facing the interior of the shell 21.

[0166] Exemplarily, the first groove 213 and the second groove 214 are both formed by a stamping process.

[0167] The housing 21 has a first wall 211 and a second wall 212 that are connected to each other. That is, the first wall 211 and the second wall 212 are two adjacent and connected walls of the housing 21. For example, in Figures 4, 5, and 6, the housing 21 is a rectangular parallelepiped structure, and the first wall 211 and the second wall 212 are two perpendicular walls to each other. 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. Correspondingly, the first direction X is the radial direction of the first wall 211, and the first outer surface 2121 is a circular arc surface.

[0168] For example, in Figures 4, 5 and 6, the shell 21 is a rectangular 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.

[0169] 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 along the first direction X with the second wall 212. In other words, the first groove section 213a is a straight groove section or an arc groove section that extends roughly along the second direction Y perpendicular to the first direction X.

[0170] 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.

[0171] 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.

[0172] 5 , the second groove 214 and the first groove segment 213 a 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.

[0173] In some embodiments, as shown in FIG4 , the battery cell 20 may further include an electrode assembly 22, which is housed in the outer shell 21. The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. 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 isolating member, and a negative electrode sheet, or a stacked structure formed by stacking a positive electrode sheet, an isolating member, and a negative electrode sheet.

[0174] Illustratively, the separator 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.

[0175] Optionally, the number of electrode assemblies 22 housed within the outer shell 21 may be one or more. For example, in FIG4 , two electrode assemblies 22 are disposed within the outer shell 21 of the battery cell 20, and the two electrode assemblies 22 are stacked along the thickness direction of the outer shell 21. In other words, 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 housed within the outer shell 21 may be one, three, four, five, six, seven, or eight, etc.

[0176] The housing 21 can also be used to contain an electrolyte, such as an electrolyte solution. The housing 21 can have various structural forms, such as a cylinder, a rectangular parallelepiped, or a prismatic structure. Similarly, the housing 21 can be made of various materials, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0177] In some embodiments, the housing 21 may include a shell 215 and an end cover 216, and a accommodating cavity is formed inside the shell 215, which is used to accommodate the electrode assembly 22, and the accommodating cavity has an opening 2151. That is, the shell 215 is a hollow structure with an opening 2151 at one end, and the end cover 216 covers the opening 2151 of the shell 215 and forms a sealed connection to form an enclosed space for accommodating the electrode assembly 22 and the electrolyte.

[0178] 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.

[0179] It should be noted that the first wall 211 provided with the first groove 213 may be the end cap 216 of the outer shell 21, or may be a wall of the shell 215 of the outer shell 21. For example, in Figures 3 and 4, the first wall 211 is the bottom wall of the shell 215, which is arranged opposite the end cap 216 in the thickness direction Z of the first wall. Correspondingly, the second wall 212 is one of the side walls of the shell 215. Of course, the structure of the battery cell 20 is not limited to this. In other embodiments, the first wall 211 may also be the end cap 216, or the first wall 211 may also be a side wall of the shell 215 adjacent to and connected to the end cap 216.

[0180] When assembling the battery cell 20 , the electrode assembly 22 may be placed in the housing 215 and filled with electrolyte. The end cap 216 may then be placed on the opening 2151 of the housing 215 to complete the assembly of the battery cell 20 .

[0181] The shell 215 can be of various shapes, such as a cylinder, a rectangular parallelepiped, or a prismatic 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 has a cylindrical structure, a cylindrical shell 215 can be selected; if the electrode assembly 22 has a rectangular parallelepiped structure, a rectangular shell 215 can be selected. Of course, the structure of the end cap 216 can also be various, such as a plate-like structure or a hollow structure with one end open. For example, in Figure 4, the shell 215 has a rectangular parallelepiped structure and the end cap 216 has a rectangular plate-like structure.

[0182] Of course, it is understandable that the shell 21 is not limited to the above structure. The shell 21 may also be other structures. For example, the shell 21 may include a shell body 215 and two end covers 216. The shell body 215 is a hollow structure with openings 2151 on opposite sides. One end cover 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 covers 216 are respectively covered on both sides of the shell body 215 to close the corresponding openings 2151. Correspondingly, the first wall 211 is one of the two end covers 216.

[0183] In some embodiments, as shown in FIG. 4 , the battery cell 20 may further include an electrode terminal 23 . The electrode terminal 23 is insulated and mounted on the housing 21 . The electrode terminal 23 is electrically connected to the electrode assembly 22 to output or input electrical energy of the battery cell 20 .

[0184] It should be noted that the electrode terminal 23 is insulated and mounted on the housing 21 , that is, there is no electrical connection between the electrode terminal 23 and the housing 21 .

[0185] In Figures 3 and 4 , the battery cell 20 includes two electrode terminals 23, which are spaced apart on the first wall 211 along the second direction Y. Correspondingly, each electrode assembly 22 has two tabs 221, with opposite polarities. The two electrode terminals 23 are electrically connected to the two tabs 221 of the electrode assembly 22, respectively, to enable input or output of the positive and negative electrodes of the battery cell 20. It should be noted that the tabs 221 of the electrode assembly 22 are formed by stacking and connecting the areas of the positive electrode sheets not coated with the positive active material layer, or by stacking and connecting the areas of the negative electrode sheets not coated with the negative active material layer. If the tabs 221 are used to output the positive electrode of the electrode assembly 22, then the tabs 221 are formed by stacking and connecting the areas of the positive electrode sheets not coated with the positive active material layer. If the tabs 221 are used to output the negative electrode of the electrode assembly 22, then the tabs 221 are formed by stacking and connecting the areas of the negative electrode sheets not coated with the negative active material layer.

[0186] 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.

[0187] Optionally, the electrode terminals 23 may be mounted on the housing 21 in various configurations. For example, in Figures 3 and 4 , both electrode terminals 23 are mounted on the end cap 216 of the housing 21. Of course, the structure of the battery cell 20 is not limited thereto. In other embodiments, both electrode terminals 23 may be mounted on the shell 215 of the housing 21. Similarly, one electrode terminal 23 may be mounted on the shell 215 of the housing 21, while the other electrode terminal 23 may be mounted on the end cap 216 of the housing 21.

[0188] In some embodiments, as shown in Figure 4, 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 assemblies 22 with the same polarity of the electrode lugs 221 to achieve electrical connection between the electrode terminal 23 and the electrode assembly 22, which is conducive to reducing the difficulty of assembly between the electrode lug 221 and the electrode terminal 23.

[0189] For example, the current collecting member 24 may be made of a variety of materials. For example, the current collecting member 24 may be made of copper, iron, aluminum, steel, or aluminum alloy.

[0190] In this embodiment, the shell 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 cracked 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 the first wall 211 is further provided with a second groove 214, wherein 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 role in separating 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 of the first groove 213 during the molding process, so as to ease the process of machining the first groove section 213a on the first wall 211. The phenomenon of local arching of the first outer surface 2121 of the second wall 212 or the first wall 211 due to local extrusion can be reduced, thereby reducing the problems of local size increase of the battery cell 20 in the first direction X or reduction in the flatness of the first wall 211, thereby improving the dimensional 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, thereby playing a certain protective role for the area of ​​the first wall 211 where the first groove section 213a is provided, thereby effectively 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, thereby alleviating 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.

[0191] According to some embodiments of the present application, as shown in Figures 5 and 6, 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, satisfying the condition 0.11≤L1 / L2≤0.44.

[0192] The minimum distance L1 between the first slot segment 213 a and the first outer surface 2121 is the minimum distance between a projection of the first slot segment 213 a in a plane perpendicular to the thickness direction Z of the first wall and the first outer surface 2121 .

[0193] Exemplarily, the outer shell 21 of the battery cell 20 has a rectangular 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.

[0194] Optionally, the ratio of the minimum distance L1 between the first groove section 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 can 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.

[0195] 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 with reference to 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 merely illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0196] Comparative Example 1

[0197] 1) Preparation of positive electrode

[0198] 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 prepared into 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 striped, and dried under vacuum conditions at 85°C for 4 hours to make the positive electrode sheet.

[0199] 2) Preparation of negative electrode sheet

[0200] Graphite, conductive agent Super P, thickener carboxymethyl cellulose (CMC), and adhesive styrene-butadiene rubber (SBR) were mixed evenly in deionized water to prepare a negative electrode slurry, wherein the solid content in the negative electrode slurry was 30wt%, and the mass ratio of graphite, silicon oxide, Super P, CMC, and adhesive styrene-butadiene rubber (SBR) in the solid components was 88:7:3:2. The negative electrode slurry was coated on the upper and lower surfaces of the current collector copper foil and dried at 85°C. Then, it was cold pressed, trimmed, cut into pieces, and slit, and then dried under vacuum conditions at 120°C for 12 hours to prepare a negative electrode sheet.

[0201] 3) Preparation of electrolyte

[0202] 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.

[0203] 4) Isolation parts

[0204] A 16 μm polyethylene film was used as a separator.

[0205] 5) Preparation of battery cell 20

[0206] 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. The electrode assembly 22 is placed in an aluminum shell 21, and the electrolyte prepared above is injected into the dried shell 21. The battery cell 20 is prepared by packaging, standing, forming, shaping, and capacity testing. 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 the first groove segment 2 13a, a second slot segment 213b and a third slot segment 213c, the second slot segment 213b and the third slot segment 213c are arranged at intervals along the second direction Y and both extend along the first direction X, the first slot segment 213a is connected between the second slot segment 213b and the third slot segment 213c, the first slot segment 213a extends along the second direction Y, and the first slot segment 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 39 mm, the length in the second direction Y is 203 mm, and the minimum distance L1 between the first slot segment 213a and the first outer surface 2121 is 1.95 mm.

[0207] 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.

[0208] 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 section 213a and the first outer surface 2121 is different. The specific details are shown in Table 2.

[0209] 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 details are shown in Table 3.

[0210] 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 section 213a and the first outer surface 2121 is different. The specific details are shown in Table 4.

[0211] The following comparative examples 1-8 and embodiments 1-16 are used to process the first groove 213 under different conditions based on 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. After the processing is completed, 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:

[0212] 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 a point 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 of the experimental values ​​1, 2 and 3 to obtain the outward expansion value of the battery cell 20 in the first direction X.

[0213] Method for measuring the flatness difference of the first wall 211: four measuring points are taken in an area of ​​the first wall 211 where the first groove 213 is not provided, that is, near both ends of the first wall 211 along the first direction X, and the flatness of the four measuring points is measured. 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, and the flatness of the four experimental points is measured. The average value of the flatness of the four experimental points is calculated to obtain an experimental value of the flatness. Finally, the reference value is subtracted from the experimental value to obtain the flatness difference of the first wall 211.

[0214] The experimental results of Comparative Examples 1-2 and Examples 1-4 are shown in Table 1 below:

[0215] Table 1

[0216] The experimental results of Comparative Examples 3-4 and Examples 5-8 are shown in Table 2 below:

[0217] Table 2

[0218] The experimental results of Comparative Examples 5-6 and Examples 9-12 are shown in Table 3 below:

[0219] Table 3

[0220] The experimental results of Comparative Examples 7-8 and Examples 13-16 are shown in Table 4 below:

[0221] Table 4

[0222] As shown in Tables 1 to 4, based on the experimental results of Comparative Examples 1 to 8 and Examples 1 to 16, it can be seen 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 better 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, thereby facilitating the improvement of the dimensional consistency 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 greater than or equal to 0.11.

[0223] Similarly, referring to Tables 1 to 4, it can be seen from the experimental results of comparative examples 1-8 and embodiments 1-16 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 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 0.4 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 or less, and the flatness difference of the first wall 211 can reach 0.3 mm or less, so that the second groove 214 provided between the first groove section 213a and the first outer surface 2121 can better absorb the extruded excess material of the first groove section 213a during the molding process of the first groove section 213 of the first groove 213, thereby facilitating the improvement of the dimensional consistency 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.

[0224] In this embodiment, by setting 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 to 0.11 to 0.44, the second groove 214 arranged between the first groove section 213a and the first outer surface 2121 can better 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, 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.

[0225] In some embodiments, please continue to refer to Figures 5 and 6. 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.

[0226] 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 more than 0.1 mm. The second groove 214 between a and the first outer surface 2121 can better 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, thereby helping to further improve the dimensional consistency of the battery cell 20 in the first direction X, and helping to further 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 0.15 to 0.4.

[0227] In this embodiment, by further setting 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 to 0.15 to 0.4, the second groove 214 can further improve the absorption effect of 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 further improving the flatness of the first wall 211 and further improving the consistency of the size of the battery cell 20 in the first direction X.

[0228] According to some embodiments of the present application, as shown in FIG. 5 and FIG. 6 , along the first direction X, the minimum distance between the first groove segment 213 a and the first outer surface 2121 is L1, satisfying 10 mm ≤ L1 ≤ 44 mm.

[0229] 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.

[0230] 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, 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, thereby reducing the difficulty of providing the second groove 214 between the first groove section 213a and the first outer surface 2121. This can also alleviate the problem of being unable to provide the second groove 214 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 problem of the second groove 214 being unable to absorb the excess material squeezed out 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. This can reduce the problem of the local size increase of the battery cell 20 or the poor flatness of the first wall 211 due to local extrusion of material during the processing of the first groove section 213a, thereby effectively improving the dimensional consistency of the housing 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 is reduced, thereby facilitating reducing the manufacturing cost of the battery cell 20.

[0231] In some embodiments, as shown in FIG. 5 and FIG. 6 , along the first direction X, the size of the battery cell 20 is L2 , which satisfies 25 mm ≤ L2 ≤ 100 mm.

[0232] 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.

[0233] In this embodiment, by setting the dimension of the battery cell 20 in the first direction X to be greater than or equal to 25 mm, the number or size of the electrode assemblies 22 accommodated within the housing 21 can be increased, thereby facilitating an improvement in the energy density of the battery cell 20. Furthermore, the difficulty in manufacturing the battery cell 20 caused by the battery cell 20 being too small in the first direction X can be alleviated, thereby reducing the difficulty in manufacturing the battery cell 20 and facilitating improved production efficiency of the battery cell 20. By setting the dimension of the battery cell 20 in the first direction X to be less than or equal to 100 mm, the difficulty in subsequently assembling the battery cells 20 into groups caused by the battery cell 20 being too large in the first direction X can be alleviated, thereby reducing the difficulty in manufacturing the battery cell 20.

[0234] According to some embodiments of the present application, referring to FIG6 and further referring to FIG7, FIG7 is a partial enlarged view of point A of the housing 21 shown in FIG6. 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.

[0235] 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 bottom surface of the first groove 213 is D1. In other words, the minimum thickness of the 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 segment, the minimum residual thickness D1 of the first groove 213 is the minimum thickness of the residual portion of the first wall 211 at that groove segment; if the first groove 213 includes multiple smooth groove segments, 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 the multiple groove segments.

[0236] 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.

[0237] 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 shell 21 can preferentially crack along the first groove 213 and release the internal pressure of the battery cell 20, thereby helping to alleviate the phenomenon that the first wall 211 cracks from the area where the second groove 214 is set, causing the battery cell 20 to have a poor pressure relief effect.

[0238] 5 and 6 , 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 provided on the first surface 2111 , and the second groove 214 is provided on the second surface 2112 .

[0239] Among them, the first surface 2111 and the second surface 2112 are the surfaces on both sides of the first wall 211 respectively. For example, in Figure 6, the first surface 2111 is the surface 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.

[0240] 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 respectively disposed on two sides of the first wall 211 .

[0241] 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 process.

[0242] 6 , along the first direction X, the projections of the first groove 213 and the second groove 214 at least partially overlap. In other words, the projection of the second groove 214 in the first direction X covers at least a portion of the first groove segment 213 a of the first groove 213 .

[0243] In this embodiment, by arranging the projections of the first groove 213 and the second groove 214 in the first direction X to at least partially overlap, the second groove 214 and the first groove section 213a of the first groove 213 have overlapping areas in the first direction X. This, on the one hand, can enhance the effect of the second groove 214 on absorbing excess material extruded from the first groove section 213a during the molding process, thereby reducing the phenomenon of local size increase of the battery cell 20 or poor flatness of the first wall 211 due to local extrusion of material during the processing of the first groove section 213a of the first wall 211 of the housing 21. On the other hand, this can enhance the effect of the second groove 214 on absorbing the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deformed, thereby enhancing the buffering effect of the second groove 214 between the first groove section 213a and the second wall 212, thereby effectively reducing the phenomenon of deformation or damage in 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.

[0244] According to some embodiments of the present application, as shown in FIG6 , 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. In other words, along 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.

[0245] In this embodiment, the bottom surface of the second groove 214 is closer to the first surface 2111 in the thickness direction Z of the first wall than the bottom surface of the first groove 213, so that the second groove 214 and the first groove section 213a of the first groove 213 have an overlapping area in the first direction X. This can, on the one hand, improve the second groove 214's ability to absorb excess material extruded from the first groove section 213a during the molding process, thereby reducing the local increase in size of the battery cell 20 or poor flatness of the first wall 211 due to local extrusion of material during the processing of the first groove section 213a of the first wall 211 of the housing 21. On the other hand, this can improve the second groove 214's ability to absorb deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deforms, thereby enhancing the buffering effect of the second groove 214 between the first groove section 213a and the second wall 212, thereby effectively reducing deformation or damage to 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.

[0246] According to some embodiments of the present application, as shown in FIG5 and FIG6 , 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.

[0247] The maximum groove depth H1 of the second groove 214 is the depth of the region where the groove depth of the second groove 214 is the largest.

[0248] 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. This can, on the one hand, improve the absorption effect of the second groove 214 on the excess material squeezed out of the first groove section 213a during the molding process, thereby reducing the phenomenon of local size increase of the battery cell 20 or poor flatness of the first wall 211 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, it can improve 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, thereby improving the buffering effect of the second groove 214 between the first groove section 213a and the second wall 212, thereby effectively reducing the phenomenon of deformation or damage in 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] 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, 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, 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.

[0250] 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 any one of 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 a range value between any two of them.

[0251] 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.

[0252] Along the thickness direction Z of the first wall, the maximum groove depth of the first groove 213 can be any point value among 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., or any range value between any two of them.

[0253] 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, 1.05 mm, 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.

[0254] According to some embodiments of the present application, as shown in FIG6 and FIG7 , the first groove 213 is a multi-stage groove sequentially arranged along the direction from the first surface 2111 to the second surface 2112. Along the thickness direction Z of the first wall, in two adjacent stages of grooves, the first stage groove farther from the first surface 2111 is arranged at the groove bottom surface of the first stage groove closer 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.

[0255] 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 .

[0256] The groove in the multi-level groove arranged on the first surface 2111 is the first-level groove 2131, that is, the groove in the multi-level groove of the first groove 213 that passes through the first surface 2111 is the first-level groove 2131. By way of example, in Figures 6 and 7, 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.

[0257] Along the first direction X, the second groove 214 overlaps at least partially with 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 .

[0258] 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 also has a multi-stage groove structure.

[0259] In this embodiment, by setting the first groove 213 as a multi-stage groove arranged along the thickness direction Z of the first wall, and setting the second groove 214 and the first-stage groove 2131 of the first groove 213 to at least partially overlap in projection on the first direction X, 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, on the one hand, improving the absorption effect of the second groove 214 on the residual material squeezed out of the first groove segment 213a during the molding process of the multi-stage groove, so as to further reduce the first wall 211 of the shell 21 during the molding process. On the other hand, the second groove 214 can further enhance the effect of absorbing the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deformed, thereby further enhancing 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.

[0260] According to some embodiments of the present application, as shown in FIG6 and FIG7 , 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 stages of grooves, the first-stage groove farther from the first surface 2111 is arranged at the groove bottom surface of the first-stage groove closer 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 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.

[0261] 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.

[0262] In this embodiment, by setting the first groove 213 to be arranged as a multi-stage groove along the thickness direction Z of the first wall, and setting the groove bottom surface of the second groove 214 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, 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 direction X. On the one hand, the absorption effect of the second groove 214 on the residual material squeezed out of the first groove segment 213a during the molding process of the multi-stage groove can be improved, so as to further reduce external During the processing of the first groove section 213a, the first wall 211 of the shell 21 may cause the local size of the battery cell 20 to increase or the flatness of the first wall 211 to be poor due to local extrusion. 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, thereby further enhancing 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.

[0263] According to some embodiments of the present application, as shown in Figures 6 and 7, the first groove 213 is a multi-stage groove sequentially arranged along the direction from the first surface 2111 to the second surface 2112. Along the thickness direction Z of the first wall, in two adjacent stages of grooves, the first stage groove farther from the first surface 2111 is arranged at the groove bottom surface of the first stage groove closer to the first surface 2111. Among the multi-stage grooves, the groove arranged on the first surface 2111 is the first stage groove 2131. The maximum groove depth of the second groove 214 is H1, and the minimum residual thickness of the first stage groove 2131 is D3, satisfying H1 ≥ D3.

[0264] The minimum residual thickness of the first-stage 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 bottom surface of the first-stage groove 2131 of the first groove 213 is D3. In other words, the minimum thickness of the bottom wall of the first-stage 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, the minimum residual thickness D3 of the first-stage groove 2131 is the minimum thickness of the residual portion of the first wall 211 at the first-stage groove 2131 in that groove segment; if the first groove 213 includes multiple smooth groove segments, the minimum residual thickness D3 of the first-stage groove 2131 is the minimum value of the thickness of the residual portion of the first wall 211 at the first-stage groove 2131 in the multiple groove segments.

[0265] In this embodiment, by setting the first groove 213 as a multi-stage groove arranged 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, 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, on the one hand, improving the absorption effect of the second groove 214 on the residual material squeezed out of the first groove segment 213a during the molding process of the multi-stage groove, so as to further reduce the first wall 211 of the shell 21 during the processing of the first groove 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, thereby further enhancing 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.

[0266] According to some embodiments of the present application, referring to Figures 8 and 9 , Figure 8 is a bottom view of the housing 21 of a battery cell 20 provided in further embodiments of the present application, and Figure 9 is a partial cross-sectional view of the housing 21 of a battery cell 20 provided in further 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 that are opposed to each other, and the first groove 213 and the second groove 214 are both provided on the first surface 2111.

[0267] 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.

[0268] For example, in Figure 9, 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.

[0269] 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 achieve the mutual spacing and avoidance between the first groove 213 and the second groove 214 during the processing, which is beneficial 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 achieved without flipping the first wall 211, which is beneficial to optimizing the production rhythm of the battery cell 20.

[0270] According to some embodiments of the present application, as shown in FIG9 , the first groove 213 is a multi-stage groove sequentially arranged along the direction from the first surface 2111 to the second surface 2112. Along the thickness direction Z of the first wall, in two adjacent stages of grooves, the first-stage groove farther from the first surface 2111 is arranged at the groove bottom surface of the first-stage groove closer 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.

[0271] 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 .

[0272] The groove in the multi-level groove arranged on the first surface 2111 is the first-level groove 2131, that is, the groove in the multi-level groove of the first groove 213 that passes through the first surface 2111 is the first-level groove 2131. By way of example, in Figure 9, 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.

[0273] Along the thickness direction Z of the first wall, the bottom surface of the first 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 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 groove 2131.

[0274] 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 also has a multi-stage groove structure.

[0275] In this embodiment, the bottom surface of the first-stage groove 2131 is closer to the first surface 2111 in the thickness direction Z of the first wall than the bottom surface of the second groove 214, so that the second groove 214 covers the first-stage groove 2131 in the first direction X. This improves the ability of the second groove 214 to absorb excess material extruded from the first groove segment 213a during the machining process to form the multi-stage grooves, thereby reducing the local increase in size of the battery cell 20 or poor flatness of the first wall 211 due to local material extrusion during the machining of the first groove segment 213a on the first wall 211 of the housing 21. Furthermore, the second groove 214 improves its ability to absorb deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal or external impact forces and deforms, thereby enhancing the buffering effect of the second groove 214 between the first groove segment 213a and the second wall 212, thereby effectively reducing deformation or damage to the area of ​​the first wall 211 where the first groove 213 is provided when the battery cell 20 is subjected to internal or external impact forces.

[0276] According to some embodiments of the present application, as shown in FIG9 , the first groove 213 is a multi-stage groove sequentially arranged along the direction from the first surface 2111 to the second surface 2112. Along the thickness direction Z of the first wall, in two adjacent stages of grooves, the first stage groove farther from the first surface 2111 is arranged at the bottom surface of the first stage groove closer to the first surface 2111. The groove of the multi-stage groove arranged on the first surface 2111 is the first stage 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 stage groove 2131 is H2, satisfying H1>H2.

[0277] It should be noted that, if the first groove 213 includes only one smooth groove segment in an embodiment, 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 the first groove 213 includes multiple smooth groove segments in an embodiment, 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.

[0278] 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 has a structure covering the first-stage groove 2131 of the first groove segment 213a in the first direction X. This, on the one hand, can improve the second groove 214's ability to absorb excess material squeezed out of the first groove segment 213a during the processing of the multi-stage groove, thereby reducing the phenomenon of local size increase of the battery cell 20 or poor flatness of the first wall 211 due to local material squeezing out during the processing of the first groove segment 213a of the first wall 211 of the housing 21. On the other hand, this can improve the second groove 214's ability to absorb deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces and deforms, thereby enhancing the buffering effect of the second groove 214 between the first groove segment 213a and the second wall 212, thereby effectively reducing the phenomenon of deformation or damage to the battery cell 20 in 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.

[0279] According to some embodiments of the present application, as shown in Figures 6 and 9, the first surface 2111 is the surface of the first wall 211 on the side facing away from the interior of the housing 21. In other words, the first surface 2111 is the surface of the first wall 211 in the thickness direction Z of the first wall that is located away from the electrode assembly 22.

[0280] 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 facing away from the interior of the shell 21, the first groove 213 is set on the side of the first wall 211 facing away from the interior of the shell 21, thereby facilitating the formation of the first groove 213 on the first wall 211 of the shell 21, which is beneficial to reducing the processing difficulty of the first groove 213 and improving the production efficiency of the battery cell 20.

[0281] According to some embodiments of the present application, as shown in Figures 5 and 6 and Figures 8 and 9 , the housing 21 of the battery cell 20 has a rectangular parallelepiped structure. Along a first direction X, the housing 21 has two second walls 212 disposed opposite each other in the first direction X. The two second walls 212 are respectively connected to opposite sides of the first wall 211. Along the first direction X, a first groove section 213a is located between the two second walls 212, and a second groove 214 is provided between the first groove section 213a and the first outer surfaces 2121 of the two second walls 212.

[0282] 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.

[0283] 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.

[0284] 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 excess material extruded from both sides during the molding process of the first groove section 213a, thereby further reducing the phenomenon of local size increase of the battery cell 20 or poor flatness of the first wall 211 due to local extrusion of material 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, thereby absorbing 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, thereby further reducing the phenomenon of deformation or damage in 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.

[0285] According to some embodiments of the present application, as shown in FIG. 5 and FIG. 8 , 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.

[0286] 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.

[0287] 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 of the first groove section 213a 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.

[0288] According to some embodiments of the present application, as shown in FIG. 5 and FIG. 8 , along the thickness direction Z of the first wall, the projection of the second groove 214 extends beyond the two ends of the projection of the first groove segment 213 a at both ends in its extension direction.

[0289] The projection of the second groove 214 extends beyond the two ends of the projection of the first groove section 213a at both ends in its extension direction, that is, the size of the second groove 214 in its extension direction is larger than that of the first groove section 213a, and the two ends of the second groove 214 in its extension direction extend beyond the two ends of the first groove section 213a.

[0290] 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 into 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, thereby enhancing the absorption effect of the second groove 214 on the residual material extruded during the molding process of the first groove section 213a, and enhancing 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.

[0291] In some embodiments, please continue to refer to Figures 5 and 8, the second groove 214 extends along the second direction Y, and along the second direction Y, the two ends of the second groove 214 extend out of the two ends of the first groove section 213a respectively, and the first direction X, the second direction Y and the thickness direction Z of the first wall are perpendicular to each other.

[0292] For example, in FIG. 5 and FIG. 8 , the second groove 214 and the first groove segment 213 a are both linear structures extending along the second direction Y. As shown in FIG.

[0293] In this embodiment, by setting the second groove 214 as a structure extending along the second direction Y, it is beneficial to improve the regularity of the shape of the second groove 214, thereby reducing the processing difficulty of the second groove 214, and facilitating setting the second groove 214 as a structure in which both ends in the second direction Y respectively exceed the two ends of the first groove section 213a, so as to reduce the manufacturing difficulty of the battery cell 20, and further help improve the production efficiency of the battery cell 20.

[0294] According to some embodiments of the present application, referring to FIG10 , which is a bottom view of the housing 21 of a battery cell 20 provided in still further embodiments of the present application, the first groove 213 may further include a second groove section 213b , wherein the first groove section 213a is connected to the second groove section 213b , and the first groove section 213a and the second groove section 213b together define a predetermined pressure relief area 2113 . The predetermined pressure relief area 2113 is configured to be opened when the first wall 211 is ruptured along at least a portion of the first groove 213 , thereby relieving the internal pressure of the battery cell 20 .

[0295] Among them, the first groove section 213a and the second groove section 213b jointly define the 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 set along the edge of the predetermined pressure relief area 2113.

[0296] 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 set 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.

[0297] For example, in FIG10 , 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 an "L"-shaped first groove 213. 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, as shown in FIG5 , so that the wall portion forms a predetermined pressure relief area 2113 on both sides of the first slot segment 213a.

[0298] It should be noted that, in the embodiment where the first groove 213 is a multi-stage groove, the first groove section 213 a and the second groove section 213 b both have a multi-stage groove structure.

[0299] 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, it can increase the pressure relief area of ​​the battery cell 20 to increase the pressure relief rate of the battery cell 20. On the other hand, it makes the position where the first groove section 213a and the second groove section 213b are interconnected weaker, which is easier to crack and open the predetermined pressure relief area 2113 to release the internal pressure of the battery cell 20.

[0300] According to some embodiments of the present application, as shown in Figures 5 and 8 , 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 each other along a second direction Y, where 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. The first groove section 213a, the second groove section 213b, and the third groove section 213c collectively define a predetermined pressure relief area 2113. The predetermined pressure relief area 2113 is configured to be opened and flipped around the second groove 214 when the first wall 211 is ruptured along the first groove 213 to release internal pressure of the battery cell 20.

[0301] 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. For example, in Figures 5 and 8, the second slot segment 213b and the third slot segment 213c both extend along the first direction X.

[0302] 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.

[0303] 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 slot section 213a, the second slot section 213b and the third slot section 213c. 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.

[0304] Alternatively, as shown in Figures 5 and 8 , the first groove 213 formed by the first groove segment 213a, the second groove segment 213b, and the third groove segment 213c can be shaped like an "H" to form two predetermined pressure relief areas 2113 on the first wall 211, with the two predetermined pressure relief areas 2113 located on either side of the first groove segment 213a in the first direction X. Of course, the first groove 213 can also have other structures. See Figure 11, which is a bottom view of the housing 21 of the battery cell 20 provided in other embodiments of the present application. The first groove 213 formed by the first groove segment 213a, the second groove segment 213b, and the third groove segment 213c can be shaped like a "U", where one end of the first groove segment 213a is connected to one end of the second groove segment 213b, and the other end is connected to one end of the third groove segment 213c, to form a predetermined pressure relief area 2113 on the first wall 211.

[0305] It should be noted that, in the embodiment where the first groove 213 is a multi-stage groove, the first groove section 213 a , the second groove section 213 b and the third groove section 213 c are all multi-stage groove structures.

[0306] 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 improve 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, thereby further improving the pressure relief effect of the battery cell 20.

[0307] In some embodiments, referring to Figures 5 and 8, the connection position of the second slot segment 213b and the first slot segment 213a deviates from the two ends of the second slot segment 213b, and the connection position of the third slot segment 213c and the first slot segment 213a deviates from the two ends of the third slot segment 213c, so as to form a predetermined pressure relief area 2113 on both sides of the first slot segment 213a.

[0308] 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 an approximately "H"-shaped structure.

[0309] 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 predetermined pressure relief areas 2113 can be formed on both sides of the first groove section 213a of the first groove 213, and the two predetermined pressure relief areas 2113 can be opened in a split manner to relieve pressure when the battery cell 20 is relieved of pressure, 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.

[0310] In some embodiments, referring to Figures 5 and 8 , the first slot segment 213a, the second slot segment 213b, and the third slot segment 213c all extend along straight lines, with the second slot segment 213b and the third slot segment 213c both being perpendicular to the first slot segment 213a. In other words, the extension direction of the first slot segment 213a is perpendicular to the extension directions of the second slot segment 213b and the third slot segment 213c, so that the first groove 213 formed by the first slot segment 213a, the second slot segment 213b, and the third slot segment 213c form a regular "H"-shaped structure. Predetermined pressure relief areas 2113 are formed on both sides of the first slot segment 213a. The areas of the two predetermined pressure relief areas 2113 may be the same or different.

[0311] 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.

[0312] 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 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 conducive to reducing the processing difficulty of the first groove 213, thereby reducing 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.

[0313] According to some embodiments of the present application, referring to Figure 12, which is a bottom view of the housing 21 of the battery cell 20 provided in yet other embodiments of the present application, the first slot section 213a, the second slot section 213b, and the third slot section 213c all extend along an arc trajectory.

[0314] For example, in Figure 12, the two ends of the first slot segment 213a are respectively connected to one end of the second slot segment 213b and one end of the third slot segment 213c, and the first slot segment 213a, the second slot segment 213b and the third slot segment 213c all extend along an arc trajectory, so that the first slot segment 213a, the second slot segment 213b and the third slot segment 213c form a first groove 213 with a "C"-shaped structure.

[0315] 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 after it is cracked along the first groove section 213a, the second groove section 213b and the third groove section 213c to release the internal pressure of the battery cell 20.

[0316] According to some embodiments of the present application, as shown in Figures 5 and 8, the first groove 213 may further include a fourth groove segment 213d, which is located between the second groove segment 213b and the third groove segment 213c, and is connected to the first groove segment 213a.

[0317] Exemplarily, the fourth slot segment 213 d extends along the first direction X, and the fourth slot segment 213 d and the first slot segment 213 a are perpendicular to each other.

[0318] Exemplarily, the distance between the fourth slot segment 213 d and the second slot segment 213 b in the second direction Y is equal to the distance between the fourth slot segment 213 d and the third slot segment 213 c in the second direction Y.

[0319] It should be noted that, in the embodiment where the first groove 213 is a multi-stage groove, the fourth groove section 213 d also has a multi-stage groove structure.

[0320] 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.

[0321] According to some embodiments of the present application, as shown in FIG5 and FIG8 , along the thickness direction Z of the first wall, the projection of the first groove 213 and the projection of the second groove 214 do not overlap. In other words, 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. The first groove 213 and the second groove 214 may be spaced apart in the first direction X, or they may be spaced apart in the thickness direction Z of the first wall.

[0322] In this embodiment, by setting the first groove 213 and the second groove 214 to a structure in which their projections in the thickness direction Z of the first wall do not overlap with each other, 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 process can be reduced, and on the other hand, the phenomenon of the first wall 211 cracking along the second groove 214 when the first wall 211 cracks along the first groove 213 to release pressure 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.

[0323] In some embodiments, please continue to refer to FIG. 5 and FIG. 8 , along the first direction X, the second groove 214 is spaced apart from the first groove 213 .

[0324] Exemplarily, the second groove 214 is spaced apart from the second groove section 213 b and the third groove section 213 c in the first direction X, and the second groove 214 is parallel to the first groove section 213 a .

[0325] 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 provided when it is opened, and the flipping angle of the predetermined pressure relief area 2113 after being opened can be increased, thereby increasing the pressure relief area of ​​the battery cell 20.

[0326] In some embodiments, the first groove 213 is stamped and formed on the first wall 211 .

[0327] It should be noted that if the first groove 213 is a primary groove structure, when forming the first groove 213 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 forming the first groove 213 on the first wall 211, the first wall 211 can be punched multiple times, each time punching out a primary groove, and the first groove 213 is finally formed after multiple stampings.

[0328] In this embodiment, the first groove 213 is stamped and formed on 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 .

[0329] In some embodiments, the second groove 214 is stamped and formed on the first wall 211 .

[0330] In this embodiment, the second groove 214 is stamped and formed on the first wall 211 , so that the second groove 214 is formed in a simple manner, which is beneficial for reducing the production cost of the battery cell 20 .

[0331] According to some embodiments of the present application, as shown in Figures 3, 4, 5 and 6, the outer shell 21 may include a shell 215 and an end cover 216. The interior of the shell 215 forms a accommodating cavity with an opening 2151, and the accommodating cavity is used to accommodate the electrode assembly 22. The end cover 216 closes the opening 2151, and the shell 215 includes a first wall 211.

[0332] The shell 215 includes an integrally formed side wall and bottom wall, that is, the shell 215 is manufactured using an integral molding process, such as an integral molding process such as stamping, casting or extrusion molding. In other words, the side wall and bottom wall of the shell 215 are an integral structure.

[0333] The housing 215 includes a first wall 211, that is, the first wall 211 is a wall of the housing 215. For example, in Figures 5 and 6, the first wall 211 is the bottom wall of the housing 215, which is arranged opposite to the end cover 216 in the thickness direction Z of the first wall. Correspondingly, the second wall 212 is one of the side walls of the housing 215. In other words, the first groove 213 and the second groove 214 are both provided on the bottom wall of the housing 215. Of course, in other embodiments, the first wall 211 may also be a side wall of the housing 215.

[0334] In this embodiment, by setting the first wall 211 of the outer shell 21 as a wall of the shell 215, the battery cell 20 adopting this 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 interconnection 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, thereby reducing the impact on the area where the first groove 213 and the second groove 214 are provided on the first wall 211, and further helping to reduce 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, thereby improving the service life and reliability of the battery cell 20.

[0335] It should be noted that the structure of the battery cell 20 is not limited to this. In some embodiments, the battery cell 20 may also have other structures. For example, the outer shell 21 may include a shell 215 and an end cap 216. The interior of the shell 215 forms a receiving cavity with an opening 2151 for accommodating the electrode assembly 22. The end cap 216 closes the opening 2151. The end cap 216 is a first wall 211. In other words, the second groove 214 and the first groove 213 are both provided on the end cap 216 of the outer shell 21. Correspondingly, the second wall 212 is one of the side walls of the shell 215.

[0336] In this embodiment, by setting the first wall 211 of the shell 21 as the end cover 216 of the shell 21 for closing the opening 2151, the battery cell 20 adopting this structure facilitates the provision of 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.

[0337] 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. A accommodating cavity is formed inside the shell 215, and the accommodating cavity is used to accommodate the electrode assembly 22. Openings 2151 are formed at both opposite ends of the shell 215, and the two openings 2151 are connected to the accommodating 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.

[0338] 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 for setting 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.

[0339] Of course, the structure of the battery cell 20 is not limited to this. In the embodiment where the outer shell 21 includes a shell 215 and two end caps 216, the shell 215 may also include a first wall 211, that is, the first wall 211 is a wall of the shell 215. By configuring the first wall 211 of the outer shell 211 as a wall of the shell 215, the battery cell 20 adopting this structure can position the area of ​​the outer shell 211 where the first groove 213 and the second groove 214 are provided away from the end caps 216, thereby effectively alleviating the stress generated by the connection between the end caps 216 and the shell 215 from acting on the area where the first groove 213 and the second groove 214 are provided, thereby reducing the impact on the area where the first groove 213 and the second groove 214 are provided on the first wall 211, thereby facilitating reducing the risk of cracking or structural strength degradation in the area where the first groove 213 and the second groove 214 are provided on the first wall 211 under the action of stress, thereby improving the service life and reliability of the battery cell 20.

[0340] According to some embodiments of the present application, the material of the first wall 211 includes steel.

[0341] Exemplarily, the material of the first wall 211 may be carbon steel, alloy steel, stainless steel, or the like.

[0342] 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.

[0343] 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.

[0344] In some embodiments, the steel material is carbon steel or stainless steel.

[0345] Illustratively, the carbon steel may be low carbon steel, medium carbon steel, or high carbon steel.

[0346] In this embodiment, carbon steel or stainless steel is used as the material of the first wall 211 , which is low in cost and easy to manufacture.

[0347] According to some embodiments of the present application, the material of the first wall 211 includes aluminum alloy.

[0348] 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.

[0349] 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 is beneficial to reducing the manufacturing difficulty of the first groove 213 and the second groove 214.

[0350] 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 individual elements ≤ 0.03%.

[0351] In this embodiment, this aluminum alloy belongs to the third series aluminum. The use of this 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 can improve the processing accuracy of the first groove 213 and the second groove 214, thereby helping to improve the pressure relief consistency of the battery cell 20.

[0352] 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%.

[0353] 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.

[0354] According to some embodiments of the present application, the present application further provides a battery 100 , which includes the battery cell 20 of any of the above solutions.

[0355] As shown in FIG. 2 , the battery 100 may further include a box body 10 , in which the battery cells 20 are accommodated.

[0356] 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 .

[0357] 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, 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 can 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.

[0358] 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 rectangular parallelepiped, etc. For example, in FIG2 , the box body 10 is a rectangular parallelepiped structure.

[0359] Optionally, the number of battery cells 20 disposed within the housing 10 may be one or more. For example, in FIG2 , the housing 10 of the battery 100 includes multiple battery cells 20, which may be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a configuration in which multiple battery cells 20 are connected in both series and parallel. Multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure formed by the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 100 may comprise multiple battery cells 20 that are first connected in series, in parallel, or in a hybrid configuration to form a battery module, which is then further connected in series, in parallel, or in a hybrid configuration to form a single structure, which is then housed within the housing 10.

[0360] The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component that connects the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0361] It should be noted that in some embodiments, the battery 100 may not be provided with a housing 10. The battery 100 includes multiple battery cells 20, and the battery 100 composed of multiple battery cells 20 can be directly assembled on an electrical device to provide electrical energy to the electrical device through the multiple battery cells 20. In other words, the housing 10 can serve as part of the electrical device. Taking the vehicle 1000 as an example, the housing 10 can serve as part of the chassis structure of the vehicle 1000. For example, a portion of the housing 10 can form at least a portion of the floor of the vehicle 1000, or a portion of the housing 10 can form at least a portion of the crossbeam or longitudinal beam of the vehicle 1000.

[0362] According to some embodiments of the present application, the present application further provides an electrical device, which includes the battery cell 20 of any of the above solutions, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0363] The electrical device may be any of the aforementioned devices or systems using the battery cell 20 .

[0364] According to some embodiments of the present application, as shown in Figures 3 to 7 , a battery cell 20 is provided. The battery cell 20 includes a housing 21 and an electrode assembly 22. The housing 21 has a rectangular parallelepiped structure and includes a shell 215 and an end cap 216. The interior of the shell 215 forms a receiving cavity with an opening 2151, in which the electrode assembly 22 is received. The end cap 216 closes the opening 2151. The shell 215 includes a bottom wall and side walls surrounding the bottom wall. 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 encloses the opening 2151. The bottom wall of the shell 215 is a first wall 211. The two side walls of the shell 215 that are connected to either side of the first wall 211 in a first direction X are second walls 212. The width of the first wall 211 and the thickness of the second wall 212 are both in the first direction X. The length of the first wall 211 is in the second direction Y. 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 rupture along at least a portion 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 respectively provided with a first groove 213a and a second groove section 213b. 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 between 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 between the third slot section 213c and the first slot section 213a deviates from the two ends of the third slot section 213c, so as to form predetermined pressure relief areas 2113 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 interior of the housing 21. A second groove 214 is provided between the first groove section 213a and the first outer surface 2121 of each of the second walls 212. The second grooves 214 extend along the second direction Y, with the projection of the second grooves 214 in the thickness direction Z of the first wall 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 open and rotate around the second grooves 214 when the first wall 211 ruptures along the first grooves 213, thereby releasing internal pressure from the battery cell 20. Along the first direction X, the first groove 213 is located between the two second grooves 214, and both second grooves 214 are spaced apart from the first groove 213.Along the first direction X, the minimum distance between the first groove segment 213a and the first outer surface 2121 is L1. The size of the battery cell 20 is L2, satisfying 0.11 ≤ L1 / L2 ≤ 0.44, 10 mm ≤ L1 ≤ 44 mm, and 25 mm ≤ L2 ≤ 100 mm. 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, satisfying 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 facing away from the interior of the housing 21. The first groove 213 is provided on the first surface 2111, and the second groove 214 is provided 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 in the multi-level groove 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 H1≥D3.

[0365] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0366] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, comprising: A housing having a first wall and a second wall connected to each other. The first wall is provided with a first groove, and the first wall is configured to be able to crack along at least part of the first groove when the battery cell relieves pressure, so as to release the internal pressure of the battery cell. 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; Wherein, the first wall is further provided with a second groove. Along the first direction, the second wall has a first outer surface facing away from the interior of the housing, 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. The first direction is perpendicular to the thickness direction of the first wall.

2. The battery cell according to claim 1, wherein, 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, wherein, 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 any one of claims 1-3, wherein, Along the first direction, the minimum distance between the first groove section and the first outer surface is L1, satisfying 10mm ≤ L1 ≤ 44mm.

5. The battery cell according to any one of claims 1-4, wherein, Along the first direction, the size of the battery cell is L2, satisfying 25mm ≤ L2 ≤ 100mm.

6. The battery cell according to any one of claims 1-5, wherein, Along the thickness direction of the first wall, the minimum remaining thickness of the first groove is D1, and the minimum remaining thickness of the second groove is D2, satisfying D2 > D1.

7. The battery cell according to any one of claims 1-6, wherein, Along the thickness direction of the first wall, the first wall has opposite first and second surfaces; 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, wherein, Along the first direction, at least part of the projections of the first groove and the second groove overlap.

9. The battery cell according to claim 7 or 8, wherein, Along the thickness direction of the first wall, the bottom surface of the second groove is closer to the first surface than the bottom surface of the first groove.

10. The battery cell according to any one of claims 7-9, wherein, Along the thickness direction of the first wall, the maximum groove depth of the second groove is H1, and the minimum remaining thickness of the first groove is D1, satisfying H1 > D1.

11. The battery cell according to any one of claims 7-10, wherein, The first groove is a multi-stage groove sequentially arranged along the direction from the first surface to the second surface. Along the thickness direction of the first wall, in two adjacent stages of the grooves, the stage of the groove far from the first surface is arranged on the bottom surface of the stage of the groove close to the first surface; Wherein, the groove arranged on the first surface in the multi-stage groove is the first-stage groove. Along the first direction, at least part of the projections of the second groove and the first-stage groove overlap.

12. The battery cell according to any one of claims 7-11, wherein, The first groove is a multi-stage groove sequentially arranged in the direction from the first surface to the second surface. Along the thickness direction of the first wall, in two adjacent stages of the grooves, the groove in the stage farther from the first surface is arranged on the bottom surface of the groove in the stage closer to the first surface; Among them, the groove arranged on the first surface in the multi-stage groove is the first-stage groove. Along the thickness direction of the first wall, the bottom surface of the second groove is flush with the bottom surface of the first-stage groove or the bottom surface of the second groove is closer to the first surface than the bottom surface of the first-stage groove.

13. The battery cell according to any one of claims 7-12, wherein, The first groove is a multi-stage groove sequentially arranged in the direction from the first surface to the second surface. Along the thickness direction of the first wall, in two adjacent stages of the grooves, the groove in the stage farther from the first surface is arranged on the bottom surface of the groove in the stage closer to the first surface; Among them, the groove arranged on the first surface in the multi-stage groove is the first-stage groove. The maximum groove depth of the second groove is H1, and the minimum remaining thickness of the first-stage groove is D3, satisfying H1≥D3.

14. The battery cell according to any one of claims 1-6, wherein, Along the thickness direction of the first wall, the first wall has opposite first and second surfaces; Among them, the first groove and the second groove are both arranged on the first surface.

15. The battery cell according to claim 14, wherein, The first groove is a multi-stage groove sequentially arranged in the direction from the first surface to the second surface. Along the thickness direction of the first wall, in two adjacent stages of the grooves, the groove in the stage farther from the first surface is arranged on the bottom surface of the groove in the stage closer to the first surface; Among them, the groove arranged on the first surface in the multi-stage groove is the first-stage groove. 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 or 15, wherein, The first groove is a multi-stage groove sequentially arranged in the direction from the first surface to the second surface. Along the thickness direction of the first wall, in two adjacent stages of the grooves, the groove in the stage farther from the first surface is arranged on the bottom surface of the groove in the stage closer to the first surface; Among them, the groove arranged on the first surface in the multi-stage groove is the first-stage groove. 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-stage groove is H2, satisfying H1>H2.

17. The battery cell according to any one of claims 7-16, wherein, The first surface is the surface on the side of the first wall facing away from the interior of the housing.

18. The battery cell according to any one of claims 1-17, wherein, Along the first direction, the housing has two second walls oppositely arranged in the first direction, and the two second walls are respectively connected to both sides of the first wall; Among them, 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.

19. The battery cell according to any one of claims 1-18, wherein, The first wall is a rectangular structure, and both the width direction of the first wall and the thickness direction of the second wall are parallel to the first direction.

20. The battery cell according to any one of claims 1-19, wherein Along the thickness direction of the first wall, the projections of the second groove extend beyond the two ends of the projection of the first groove section at both ends in its extending direction.

21. The battery cell according to claim 20, wherein, The second groove extends in a second direction. Along the second direction, both ends of the second groove extend out of both ends of the first groove section respectively. The first direction, the second direction, and the thickness direction of the first wall are perpendicular to each other in pairs.

22. The battery cell according to any one of claims 1-21, wherein, 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 cracks along at least part of the first groove to relieve the internal pressure of the battery cell.

23. The battery cell according to any one of claims 1-21, wherein, 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 in the second direction, and the second direction is perpendicular to the first direction; Wherein, the first groove section connects the second groove section and the third groove section. 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 flip around the second groove when the first wall cracks along the first groove to relieve the internal pressure of the battery cell.

24. The battery cell according to claim 23, wherein, The connection position of the second groove section and the first groove section deviates from both ends of the second groove section, and the connection position of the third groove section and the first groove section deviates from both ends of the third groove section, so that the predetermined pressure relief areas are formed on both sides of the first groove section.

25. The battery cell according to claim 24, wherein, The first groove section, the second groove section, and the third groove section all extend along a straight track, and both the second groove section and the third groove section are perpendicular to the first groove section.

26. The battery cell according to claim 23, wherein, The first groove section, the second groove section, and the third groove section all extend along an arc track.

27. The battery cell according to any one of claims 23-26, wherein, 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 any one of claims 1-27, wherein, Along the thickness direction of the first wall, the projection of the first groove does not overlap with the projection of the second groove.

29. The battery cell according to claim 28, wherein, Along the first direction, the second groove is arranged at intervals with the first groove.

30. The battery cell according to any one of claims 1-29, wherein, The first groove is formed on the first wall by stamping.

31. The battery cell according to any one of claims 1-30, wherein, The second groove is formed on the first wall by stamping.

32. The battery cell according to any one of claims 1-31, wherein, The housing includes: A housing body, which forms an accommodation cavity with an opening inside, and the accommodation cavity is used to accommodate the electrode assembly; An end cover, which closes the opening; Wherein, the housing body includes the first wall; or The end cover is the first wall.

33. The battery cell according to any one of claims 1-31, wherein, The housing includes: A housing body, which forms an accommodation cavity inside, and the accommodation cavity is used to accommodate the electrode assembly. Openings are formed at both opposite ends of the housing body, and both of the two openings communicate with the accommodation cavity; Two end covers, which respectively close the two openings; Wherein, one of the two end covers is the first wall; or The housing body includes the first wall.

34. The battery cell according to any one of claims 1-33, wherein, The material of the first wall includes steel material.

35. The battery cell according to claim 34, wherein, The steel material is carbon steel or stainless steel.

36. The battery cell according to any one of claims 1-33, wherein, The material of the first wall includes aluminum alloy.

37. The battery cell according to claim 36, wherein, The aluminum alloy comprises components with the following mass percentages: 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%.

38. The battery cell according to claim 36, wherein, The aluminum alloy comprises components with the following mass percentages: 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 total other element components ≤ 0.15%.

39. A battery, comprising a battery cell as described in any one of claims 1-38.

40. An electrical device, comprising a battery cell as described in any one of claims 1-38, the battery cell being used for providing electrical energy.

Images