Battery monomer, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device, and belongs to the technical field of batteries. Wherein the battery monomer comprises a shell. The first wall is provided with a first groove, the first groove defines at least one preset pressure relief area, and the first wall is configured to be capable of cracking along at least part of the first groove when the battery monomer is subjected to pressure relief. The first wall is further provided with a second groove, the second groove and the first groove are arranged in the first direction, the second groove is located on one side of the first groove in the first direction, the first direction is perpendicular to the thickness direction of the first wall, and the second groove is configured to guide at least part of the preset pressure relief area to turn over so as to open at least part of the preset pressure relief area. According to the single battery, the effect of turning around the second groove after the preset pressure relief area is opened can be improved, so that the turning angle of the preset pressure relief area is increased, and the pressure relief area of the single battery is favorably increased.

Description

Technical Field

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

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

[0003] In battery technology, in order to ensure the safety of battery cells, a notch groove is generally provided on the outer shell of the battery cell to release the internal pressure of the battery cell, so that when the battery cell undergoes thermal runaway, the outer shell can be cracked at the position where the notch groove is provided to release the internal pressure of the battery cell. However, the pressure release rate of existing battery cells when thermal runaway occurs is low, which makes the battery cell have the risk of fire and explosion caused by untimely pressure release, resulting in low reliability of the battery cell. Utility Model Content

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

[0005] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell; the first wall is provided with a first groove, the first groove defines at least one predetermined pressure relief zone, and the first wall is configured to be able to split along at least part of the first groove when the battery cell releases pressure; wherein the first wall is also provided with a second groove, the second groove and the first groove are arranged along a first direction, and the second groove is located on one side of the first groove in the first direction, the first direction is perpendicular to the thickness direction of the first wall, and the second groove is configured to guide at least part of the predetermined pressure relief zone to flip so as to open at least part of the predetermined pressure relief zone.

[0006] In the above technical solution, by providing the first groove and the second groove on the first wall of the shell, and the first groove defines a predetermined pressure relief zone, so that the predetermined pressure relief zone can be opened after the first wall is cracked along at least part of the first groove, and can be turned around the position where the second groove is located to release the internal pressure of the battery cell, wherein, by arranging the first groove and the second groove in a structure arranged along the first direction, the second groove and the first groove are in a structure just in contact or arranged at intervals, so that the second groove is located on one side of the first groove in the first direction, on the one hand, the interference between the first groove and the second groove can be reduced, and the first groove and the second groove can be processed separately, and the phenomenon that the first groove tears the second groove when cracking can be alleviated, thereby facilitating the effect of turning the predetermined pressure relief zone around the second groove, and on the other hand, the effect of turning the predetermined pressure relief zone around the position where the second groove is located after being opened can be improved, so as to expand the turning angle of the predetermined pressure relief zone, thereby increasing the pressure relief area of ​​the battery cell, so as to improve the pressure relief rate of the battery cell when thermal runaway occurs, thereby reducing the risk of fire, explosion or connection failure of the battery cell due to untimely pressure relief, and facilitating the use reliability of the battery cell.

[0007] In some embodiments, along the first direction, the first groove and the second groove are spaced apart.

[0008] In the above technical solution, by setting the first groove and the second groove as a structure arranged at intervals along the first direction, the first groove and the second groove are not in contact with each other. On the one hand, the mutual influence between the first groove and the second groove during the processing 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. On the other hand, the phenomenon of the first groove tearing the second groove when it is cracked can be further alleviated, which is beneficial to improve the effect of flipping the predetermined pressure relief area around the second groove.

[0009] In some embodiments, along the first direction, the minimum distance between the projection of the first groove in the thickness direction of the first wall and the projection of the second groove in the thickness direction of the first wall is L 1 , meet, 0.1mm≤L 1 ≤4mm; optionally, 0.2mm≤L 1 ≤2mm.

[0010] In the above technical solution, by setting the minimum distance of the projections of the first groove and the second groove in the first direction along the thickness direction of the first wall to 0.1 mm to 4 mm, the minimum distance of the first groove and the second groove in the first direction is 0.1 mm to 4 mm. On the one hand, the minimum distance of the projections of the first groove and the second groove in the first direction along the thickness direction of the first wall is set to be greater than or equal to 0.1 mm to reduce the interference between the first groove and the second groove, which is conducive to reducing the difficulty of processing the first groove and the second groove on the first wall, and can further alleviate the phenomenon that the first groove tears the second groove when it is cracked. On the other hand, the minimum distance of the projections of the first groove and the second groove in the first direction along the thickness direction of the first wall is set to be less than or equal to 4 mm to increase the angle of the predetermined pressure relief zone flipping around the second groove and the pressure relief area after the predetermined pressure relief zone is opened, so as to further improve the pressure relief rate of the battery cell when thermal runaway occurs. Similarly, by setting the minimum distance of the projections of the first groove and the second groove in the thickness direction of the first wall in the first direction to 0.2 mm to 2 mm, the minimum distance of the first groove and the second groove in the first direction is 0.2 mm to 2 mm. On the one hand, the minimum distance of the projections of the first groove and the second groove in the thickness direction of the first wall in the first direction is further set to be greater than or equal to 0.2 mm, so as to further reduce the interference between the first groove and the second groove, which is conducive to further reducing the difficulty of processing the first groove and the second groove on the first wall, and can further alleviate the phenomenon that the first groove tears the second groove when cracking. On the other hand, the minimum distance of the projections of the first groove and the second groove in the thickness direction of the first wall in the first direction is set to be less than or equal to 2 mm, so as to further increase the angle of the predetermined pressure relief zone flipping around the second groove and the pressure relief area after the predetermined pressure relief zone is opened, so as to further improve the pressure relief rate of the battery cell when thermal runaway occurs, so that the battery cell can take into account the alleviation of the synchronous tearing of the second groove by the first groove while also improving the effect of flipping around the position where the predetermined pressure relief zone is located after being opened.

[0011] In some embodiments, the shell further includes a second wall and a third wall arranged opposite to each other along the first direction, the first wall connecting the second wall and the third wall, and along the first direction, the second wall has a first outer surface facing away from the interior of the shell, and the third wall has a second outer surface facing away from the interior of the shell; wherein, along the first direction, the second groove is arranged between the first groove and the first outer surface; and / or, along the first direction, the second groove is arranged between the first groove and the second outer surface.

[0012] In the above technical solution, when the second groove is provided between the first groove and the first outer surface of the second wall, the second groove is closer to the first outer surface of the second wall than the first groove, so that the stiffness of the position where the second groove is provided on the first wall is greater than the stiffness of the position where the first groove is provided on the first wall. Therefore, when the battery cell releases the internal pressure, the deformation of the first wall at the position where the first groove is located is greater than the deformation of the first wall at the position where the second groove is located, which is conducive to the area where the first groove is provided on the first wall to crack and release the internal pressure of the battery cell preferentially over the area where the second groove is provided on the first wall. On the one hand, it can alleviate the phenomenon that the first wall cracks from the area where the second groove is provided, causing poor pressure relief effect of the battery cell. On the other hand, it can realize that the predetermined pressure relief area is stably flipped open under the guidance of the bottom wall of the second groove. Similarly, when a second groove is provided between the first groove and the second outer surface of the third wall, the second groove is closer to the second outer surface of the third wall than the first groove, so that the rigidity of the position where the second groove is provided on the first wall is greater than the rigidity of the position where the first groove is provided on the first wall. Therefore, when the battery cell releases internal pressure, the deformation of the first wall at the position where the first groove is located is greater than the deformation of the first wall at the position where the second groove is located, which is conducive to the area where the first groove is provided on the first wall to crack and release the internal pressure of the battery cell preferentially over the area where the second groove is provided on the first wall. On the one hand, it can alleviate the phenomenon that the first wall cracks from the area where the second groove is provided, causing poor pressure relief effect of the battery cell. On the other hand, it can realize that the predetermined pressure relief area is stably flipped open under the guidance of the bottom wall of the second groove.

[0013] In some embodiments, along the thickness direction of the first wall, the first wall has a third outer surface facing away from the interior of the shell, and the third outer surface is connected to the first outer surface through a first arc surface; wherein, along the first direction, the second groove is located between the first arc surface and the first groove.

[0014] In the above technical solution, by arranging the second groove between the first groove and the first arc surface in the first direction, the second groove is not in contact with the corner of the shell, so as to reduce the influence of the stress at the corner of the shell on the area where the second groove is located, and can reduce the processing difficulty of the second groove.

[0015] In some embodiments, along the thickness direction of the first wall, the first wall has a third outer surface facing away from the interior of the shell, and the third outer surface is connected to the second outer surface through a second arc surface; wherein, along the first direction, the second groove is located between the second arc surface and the first groove.

[0016] In the above technical solution, by arranging the second groove between the first groove and the second arc surface in the first direction, the second groove is not in contact with the corner of the shell, so as to reduce the influence of the stress at the corner of the shell on the area where the second groove is located, and can reduce the processing difficulty of the second groove.

[0017] In some embodiments, along the first direction, the minimum distance L from the first groove to the first outer surface is 2 The minimum distance L from the first groove to the second outer surface 3 The difference between the first groove and the first outer surface is greater than or equal to 0, and the minimum distance L from the first groove to the first outer surface is 2 The minimum distance L from the first groove to the second outer surface 3 The difference between the first outer surface and the second outer surface is less than or equal to 0.1 times the distance D between the first outer surface and the second outer surface.

[0018] In the above technical solution, by setting the minimum distance L between the first groove and the first outer surface 2 and the minimum distance L between the first groove and the second outer surface 3 The difference is set to a ratio of the distance D between the first outer surface and the second outer surface between 0 and 0.1, so that the first groove is located in the middle area of ​​the first wall in the first direction, which is conducive to alleviating the phenomenon that the first groove deviates excessively from the center position of the first wall in the first direction. On the one hand, it is convenient to set the second groove on one side of the first groove along the first direction, which is conducive to reducing the difficulty of setting the second groove on the first wall. On the other hand, it makes it easier to crack the area of ​​the first wall where the first groove is set for pressure relief, so that under the same blasting pressure, the residual thickness of the area of ​​the first wall where the first groove is set can be increased to improve the fatigue resistance of the first wall, thereby effectively improving the service life and reliability of the battery cell.

[0019] In some embodiments, along the first direction, the minimum distance between the first groove and the first outer surface is L 2 , the minimum distance between the first groove and the second outer surface is L 3 , meet, 2mm≤L 2 ≤12mm; and / or, 2mm≤L 3 ≤12mm.

[0020] In the above technical solution, by setting the minimum distance between the first groove and the first outer surface to 2mm to 12mm, on the one hand, the minimum distance between the first groove and the first outer surface is set to be greater than or equal to 2mm to alleviate the difficulty in setting the second groove between the first groove and the first outer surface due to the small spacing between the first groove and the first outer surface, and can reduce the stress concentration phenomenon; on the other hand, the minimum distance between the first groove and the first outer surface is set to be less than or equal to 12mm to reduce the space waste between the first groove and the first outer surface, thereby alleviating the phenomenon that the area of ​​the first wall where the first groove is set is limited, which is beneficial to increase the area of ​​the first wall used to set the first groove. Similarly, by setting the minimum distance between the first groove and the second outer surface to 2mm to 12mm, on the one hand, the minimum distance between the first groove and the second outer surface is set to be greater than or equal to 2mm to alleviate the difficulty in setting the second groove between the first groove and the second outer surface due to the small spacing between the first groove and the second outer surface, and can reduce the stress concentration phenomenon. On the other hand, the minimum distance between the first groove and the second outer surface is set to be less than or equal to 12mm to reduce the space waste between the first groove and the second outer surface, thereby alleviating the phenomenon that the area of ​​the first wall where the first groove is set is limited, which is conducive to increasing the area of ​​the first wall used to set the first groove.

[0021] In some embodiments, along the first direction, the minimum distance L between the second groove and the first outer surface is 4 The minimum distance L from the second groove to the second outer surface 5 The difference between the first outer surface and the second outer surface is greater than or equal to 0.4 times the distance D between the first outer surface and the second outer surface; wherein the bottom of the first groove forms a first weak portion, the first wall is configured to be able to split along at least part of the first weak portion when the battery cell is depressurized, the first weak portion includes at least one weak section, the bottom of the second groove forms a second weak portion, and the cross-sectional area S of the second weak portion perpendicular to its extension direction is 2 Greater than the cross-sectional area S of the weak section perpendicular to its extension direction 1 0.7 times of the cross-sectional area S of the second weak portion perpendicular to its extension direction 2 Less than or equal to the cross-sectional area S of the weak section perpendicular to its extension direction 1 1.5 times of.

[0022] In the above technical solution, the minimum distance L between the second groove and the first outer surface is 4 The minimum distance L from the second groove to the second outer surface 5When the difference between the first outer surface and the second outer surface is greater than or equal to 0.4 times the distance D between the first outer surface and the second outer surface, the distance of the second groove from the center position of the first wall in the first direction is large, so that the second groove is closer to the first outer surface or the second outer surface, so that the stiffness of the position where the second groove is set in the first wall is greatly different from the stiffness of the position where the first groove is set in the first wall, and the stiffness has a greater impact on the first weak part and the second weak part of the first wall when cracking. If the impact of the stiffness on the first weak part and the second weak part of the first wall is not considered, the cross-sectional area of ​​the second weak part perpendicular to its extension direction only needs to be greater than the cross-sectional area of ​​the weak section perpendicular to its extension direction, that is, the cross-sectional area S of the second weak part perpendicular to its extension direction 2 Greater than the cross-sectional area S of the weak section perpendicular to its extension direction 1 , so that the first weak part breaks and releases pressure before the second weak part, and the second weak part guides the predetermined pressure relief area defined by the first groove. However, considering that the rigidity has a greater influence on the breaking of the first weak part and the second weak part (in S 1 and S 2 Under the same circumstances, the second weak part is more difficult to crack than the first weak part. Therefore, the cross-sectional area of ​​the second weak part can be set to be smaller), so that when the ratio of the cross-sectional area of ​​the second weak part perpendicular to its extension direction to the cross-sectional area of ​​the weak section perpendicular to its extension direction is greater than 0.7 and less than or equal to 1, the first weak part can be opened and depressurized before the second weak part, and the second weak part plays a guiding role in the predetermined pressure relief area defined by the first groove. Similarly, since the rigidity has a greater influence on the cracking of the first weak part and the second weak part, when the ratio of the cross-sectional area of ​​the second weak part perpendicular to its extension direction to the cross-sectional area of ​​the weak section perpendicular to its extension direction is less than or equal to 1.5, the phenomenon of excessive difference in rigidity between the second weak part and the first weak part can be alleviated, so that the rigidity of the second weak part is close to that of the first weak part, and then the obstacle to the flipping and opening of the predetermined pressure relief area can be achieved. It is easier to flip and open the predetermined pressure relief area during pressure relief, which is conducive to alleviating the explosion or burst of the battery cell caused by the untimely pressure relief of the first wall.

[0023] In some embodiments, along the first direction, the distance between the first outer surface and the second outer surface is D, satisfying 15 mm ≤ D ≤ 90 mm.

[0024] In the above technical solution, by setting the distance between the first outer surface and the second outer surface in the first direction to 15mm to 90mm, the size of the shell in the first direction is 15mm to 90mm. On the one hand, the size of the shell in the first direction is set to be greater than or equal to 15mm, so that the first wall arranged on the first wall has sufficient space in the first direction to set the first groove and the second groove, which is conducive to reducing the difficulty of setting the first wall on the first wall and setting the first groove and the second groove on the first wall. On the other hand, the size of the shell in the first direction is set to be less than or equal to 90mm to alleviate the phenomenon that the size of the battery cell in the first direction is too large and causes greater manufacturing difficulty.

[0025] 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 out of two ends of the first groove.

[0026] 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 out of the two end portions of the projection of the first groove respectively, the second groove is a structure in which both ends in its extension direction respectively exceed the two end portions of the first groove. On the one hand, the size of the second groove in its extension direction is larger than the first groove, so that the predetermined pressure relief zone defined by the first groove can be flipped around the second groove, and the flipping effect of the predetermined pressure relief zone can be improved, thereby increasing the pressure relief area of ​​the battery cell to improve the pressure relief rate of the battery cell when thermal runaway occurs. On the other hand, the absorption effect of the second groove on the excess material extruded from the first groove of the first wall during the molding process can be improved, and the separation effect of the second groove between the edge of the first groove and the first wall can be improved, so as to improve the blocking effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces.

[0027] In some embodiments, the length of the second groove is L 6 , meet, 8mm≤L 6 ≤60mm.

[0028] In the above technical solution, by setting the length of the second groove to 8mm to 60mm, on the one hand, setting the length of the second groove to be greater than or equal to 8mm can effectively reduce the processing difficulty of the second groove, and can alleviate the phenomenon that the size of the first groove is smaller due to the limitation of the second groove, which is beneficial to increase the area of ​​the first wall where the first groove is set; on the other hand, setting the length of the second groove to be less than or equal to 60mm can alleviate the phenomenon of waste caused by excessive processing of the second groove, and can reduce the space occupied by the second groove on the first wall, which is beneficial to improve the overall structural strength of the first wall.

[0029] In some embodiments, along the thickness direction of the first wall, the first groove and the second groove are respectively arranged on both sides of the first wall.

[0030] In the above technical solution, by respectively arranging the first groove and the second groove on both sides of the first wall in the thickness direction of the first wall, it is convenient to process the first groove and the second groove on both sides of the first wall respectively, which is beneficial to reduce the mutual influence of the first groove and the second groove during the processing.

[0031] In some embodiments, along the thickness direction of the first wall, the first groove is disposed on a side of the first wall facing away from the interior of the housing.

[0032] In the above technical solution, by arranging the first groove on the side of the first wall away from the inside of the shell, it is convenient to form the first groove on the first wall, which is beneficial to reduce the processing difficulty of the first groove and improve the production efficiency of the battery cell.

[0033] In some embodiments, along the thickness direction of the first wall, the second groove is disposed on a side of the first wall facing the interior of the housing.

[0034] In the above technical solution, by arranging the second groove on the side of the first wall facing the inside of the shell, the predetermined pressure relief zone can be flipped toward the outside of the shell around the bottom wall of the second groove when it is opened, thereby reducing the interference effect of the groove side surface of the second groove on the predetermined pressure relief zone during the flipping process, which is beneficial to improving the flipping effect of the predetermined pressure relief zone.

[0035] In some embodiments, the first groove includes a first groove section and two second groove sections, the two second groove sections are arranged opposite to each other along a second direction, and the second groove section and the second groove are arranged along the first direction, the first groove section connects the two second groove sections, the first groove section and the two second groove sections jointly define the predetermined pressure relief area, and the second direction is perpendicular to the thickness direction of the first wall and the first direction.

[0036] In the above technical solution, the first groove includes two second groove sections arranged relatively along the second direction and a first groove section connecting the two second groove sections, so that the first wall can be split along the first groove section and the two second groove sections when the battery cell is depressurized, so as to open the predetermined pressure relief area to release the internal pressure of the battery cell. The first groove with such a structure is convenient for processing the first groove on the first wall and forming the predetermined pressure relief area, and the predetermined pressure relief area defined by the first groove of such a structure is easier to flip around the second groove. On the other hand, the intersection of the first groove section and the second groove section is weaker, which makes it easier to split and open the predetermined pressure relief area for pressure relief.

[0037] In some embodiments, the connection positions of the two second slot sections and the first slot section are deviated from the two ends of the two second slot sections, so that the predetermined pressure relief area is formed on both sides of the first slot section along the first direction; wherein the first wall is provided with two second grooves, and along the first direction, the two second grooves are respectively located on both sides of the first groove.

[0038] In the above technical solution, by setting the connection positions of the two second groove sections and the first groove section to be located between the two ends of the corresponding second groove sections, so that the first groove section and the two second groove sections form a first groove similar to an "H"-shaped structure, predetermined pressure relief areas can be formed on both sides of the first groove section of the first groove, and the two predetermined pressure relief areas can be opened in a split manner for pressure relief when the battery cell is depressurized, which is beneficial to further increase the pressure relief effect of the battery cell and can effectively improve the pressure relief rate of the battery cell.

[0039] In some embodiments, the first slot segment and the two second slot segments extend along a straight line, and the first slot segment is perpendicular to the two second slot segments.

[0040] In the above technical solution, by setting the two second groove sections to be perpendicular to the first groove section, so that the extension direction of the first groove section is the arrangement direction of the two second groove sections, on the one hand, the regularity of the shape of the first groove can be improved, which is beneficial to reduce the processing difficulty of the first groove, so as to reduce the manufacturing cost of the battery cell; on the other hand, it is convenient for the two predetermined pressure relief areas on the first wall located on both sides of the first groove section to relieve pressure in opposite directions when the battery cell is relieved, which is beneficial to improve the pressure relief efficiency of the battery cell.

[0041] In some embodiments, the second slot segment extends along the first direction, and the length of the second slot segment in the first direction is L 7 , meet, 6mm≤L 7 ≤50mm.

[0042] In the above technical solution, by setting the second groove segment as a structure extending along the first direction, and the length of the second groove segment in the first direction is set to 6mm to 50mm, on the one hand, the length of the second groove segment is set to be greater than or equal to 6mm, so as to increase the area of ​​the predetermined pressure relief zone defined by the first groove segment and the two second groove segments, thereby facilitating the increase of the pressure relief area of ​​the battery cell, and on the other hand, the length of the second groove segment is set to be less than or equal to 50mm, so as to save the space occupied by the second groove segment on the first wall along the first direction, so that the first groove has enough space on one side of the first direction to set the second groove, so as to reduce the manufacturing difficulty of the second groove.

[0043] In some embodiments, the first groove includes a first groove section and a second groove section, the first groove section and the second groove section are connected, and the first groove section and the second groove section jointly define the predetermined pressure relief area.

[0044] In the above technical solution, by setting the first groove to have a first groove section and a second groove section connected, and the first groove section and the second groove section jointly define a predetermined pressure relief area, on the one hand, the pressure relief area of ​​the battery cell can be increased to increase the pressure relief rate of the battery cell, and on the other hand, the intersection of the first groove section and the second groove section is made weaker, and it is easier to crack and open the predetermined pressure relief area to release the internal pressure of the battery cell.

[0045] In some embodiments, the first groove is a groove extending along an arc-shaped trajectory, and the predetermined pressure relief area is located inside the first groove.

[0046] In the above technical solution, the first groove is set to a structure extending along an arc trajectory so that the predetermined pressure relief area is formed on the inner side of the first groove. The first groove with such a structure is easy to manufacture on the first wall, which is beneficial to reduce the manufacturing difficulty of the battery cell.

[0047] In some embodiments, the first groove includes a plurality of grooves sequentially arranged along the thickness direction of the first wall.

[0048] In the above technical solution, by setting the first groove as a multi-step groove structure arranged along the thickness direction of the first wall, so that the first groove is a groove structure formed by multiple processing, the first groove using this structure can reduce the depth of the first groove in a single processing under the condition of the same depth, which is beneficial to reduce the manufacturing difficulty of the first groove and the demand for manufacturing equipment, so as to reduce the manufacturing cost, and can reduce the forming force applied to the first wall during the single processing of the first groove, which is beneficial to reduce the risk of cracks in the first wall, so as to improve the production quality of the battery cell, and on the other hand, can improve the flow morphology of the first groove during the formation process, which is beneficial to the flow of the material generated when the first groove is formed, so as to improve the structural consistency of the first groove.

[0049] In some embodiments, the first wall is a rectangular structure, and a width direction of the first wall is parallel to the first direction.

[0050] In the above technical solution, by setting the first wall as a rectangular structure, and the width direction of the first wall is the first direction, the second groove is located on one side of the first groove in the width direction of the first wall, so that the second groove is provided on the side where extrusion or impact is extremely likely to occur during the molding process of the first groove, so that the second groove can also buffer the extrusion phenomenon of the molding of the first groove, and can also play a protective role in buffering the influence of stress on the first groove.

[0051] In some embodiments, along the thickness direction of the first wall, a minimum residual thickness of the second groove is greater than a minimum residual thickness of the first groove.

[0052] In the above technical solution, by setting the minimum residual thickness of the second groove to be greater than the minimum residual thickness of the first groove, the strength of the area of ​​the first wall where the first groove is set is less than the strength of the area of ​​the first wall where the second groove is set, so that the first wall can preferentially crack along the first groove and release the internal pressure of the battery cell, which helps to alleviate the phenomenon that the first wall cracks from the area where the second groove is set, causing poor pressure relief effect of the battery cell.

[0053] In some embodiments, the outer shell includes a shell and an end cover; the interior of the shell forms a accommodating cavity with an opening, and the accommodating cavity is used to accommodate the electrode assembly; the end cover closes the opening; wherein the shell includes the first wall; or, the end cover is the first wall.

[0054] In the above technical solution, by setting the first wall of the shell as a wall of the shell, the battery cell adopting this structure can make the area of ​​the shell provided with the first groove and the second groove away from the end cover, so as to effectively alleviate the influence of the stress generated by the connection between the end cover and the shell on the area of ​​the first wall provided with the first groove and the second groove, thereby facilitating the reduction of the risk of cracking or structural strength reduction in the area of ​​the first wall provided with the first groove and the second groove under the pulling action of the stress, so as to improve the service life and reliability of the battery cell. By setting the first wall of the shell as the end cover of the shell for closing the opening, the battery cell adopting this structure is convenient for setting the first groove and the second groove on the end cover, which is conducive to reducing the manufacturing difficulty of the battery cell and improving the production efficiency of the battery cell.

[0055] 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.

[0056] In the above technical solution, the shell of the shell is provided with openings at both opposite ends, and the two end covers respectively close the two openings, and the first wall is one of the two end covers. The battery cell using this structure is convenient for assembling the battery cell from both ends of the shell, which is conducive to reducing the manufacturing difficulty and assembly difficulty of the battery cell, and is convenient for setting the first groove and the second groove on the end cover, which is conducive to reducing the manufacturing difficulty of the battery cell, so as to improve the production efficiency of the battery cell. By setting the first wall of the shell as a wall of the shell, the battery cell using this structure can make the area of ​​the shell provided with the first groove and the second groove away from the end cover, so as to effectively alleviate the influence of the stress generated by the connection between the end cover and the shell on the area of ​​the first wall provided with the first groove and the second groove, thereby facilitating reducing the risk of cracking or structural strength reduction of the area of ​​the first wall provided with the first groove and the second groove under the pulling action of the stress, so as to improve the service life and reliability of the battery cell.

[0057] In a second aspect, an embodiment of the present application further provides a battery, comprising the above-mentioned battery cell.

[0058] 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

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0060] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0061] Figure 2 An exploded view of the structure of a battery provided in some embodiments of the present application;

[0062] Figure 3 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application;

[0063] Figure 4 An exploded view of the structure of a battery cell provided in some embodiments of the present application;

[0064] Figure 5 A schematic structural diagram of a shell of a battery cell housing provided in some embodiments of the present application;

[0065] Figure 6 A bottom view of a housing of a battery cell provided in some embodiments of the present application;

[0066] Figure 7 for Figure 6 A partial enlarged view of the shell at A shown;

[0067] Figure 8 A partial cross-sectional view of a shell of a battery cell housing provided in some embodiments of the present application;

[0068] Fig. 9 for Figure 8 A partial enlarged view of the B portion of the shell shown;

[0069] Fig.10 A bottom view of a housing of a battery cell provided in some other embodiments of the present application;

[0070] Fig.11 A bottom view of a shell of a battery cell housing provided in some further embodiments of the present application.

[0071] Icon: 1000-vehicle; 100-battery; 10-box; 11-first box body; 12-second box body; 20-battery cell; 21-housing; 211-first wall; 2111-third outer surface; 212-housing; 2121-accommodation chamber; 2122-opening; 2123-second wall; 2123a-first outer surface; 2124-third wall; 2124a-second outer surface; 2125-fourth wall; 2126-fifth wall; 213-end cover; 2 14-first arc surface; 215-second arc surface; 221-first groove; 2211-first groove section; 2212-second groove section; 222-predetermined pressure relief area; 223-second groove; 224-first weak part; 2241-weak section; 225-second weak part; 23-electrode assembly; 231-ear; 24-electrode terminal; 25-current collecting component; 200-controller; 300-motor; X-thickness direction of the first wall; Y-first direction; Z-second direction. DETAILED DESCRIPTION

[0072] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0073] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0074] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0075] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0076] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0077] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0078] The term "plurality" used in the present application refers to two or more (including two).

[0079] 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.

[0080] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., which is not limited in the embodiments of the present application.

[0081] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting, while allowing active ions to pass through.

[0082] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0083] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0084] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0085] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), 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 LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 、LiMn 2 O4 ), 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 O 2 (Also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O 2 (Also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O 2 (Also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (Also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (Also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and at least one of its modified compounds.

[0086] In some embodiments, the positive electrode may be a foamed metal. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, etc. When the foamed metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foamed metal, but of course, the positive electrode active material may also be provided. As an example, a lithium source material, potassium metal or sodium metal may also be filled or / and deposited in the foamed metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[0087] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0088] As an example, the negative electrode current collector may be a metal foil, a foamed metal or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, nickel or titanium, etc. may be used. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, etc. The composite current collector may include a polymer material base and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0089] 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.

[0090] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0091] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0092] 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.

[0093] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0094] In some embodiments, the separator is a separator membrane. There may be many types of separator membranes, and any known porous separator membrane with good chemical stability and mechanical stability may be selected.

[0095] As an example, the material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or may be attached to the surface of the positive and negative electrodes.

[0096] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transmit ions and isolate the positive and negative electrodes.

[0097] In some embodiments, the battery cell further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The electrolyte can be liquid, gel or solid. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0098] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0099] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0100] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0101] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0102] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, and the like.

[0103] 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.

[0104] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0105] 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.

[0106] In some embodiments, the electrode assembly is a laminate structure.

[0107] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be provided respectively, and the plurality of positive electrode sheets and the plurality of negative electrode sheets may be alternately stacked.

[0108] 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.

[0109] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded sections that are stacked.

[0110] As an example, a plurality of separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0111] As an example, the separator may be disposed continuously, and may be disposed between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0112] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0113] In some embodiments, the electrode assembly is provided with tabs, which can lead current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0114] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0115] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes but is not limited to a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery, etc.

[0116] 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.

[0117] 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.

[0118] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are accommodated in the case.

[0119] 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.

[0120] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0121] Batteries have outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient. They are an important part of the development of new energy today. The development of battery technology must consider many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the safety of the battery also needs to be considered.

[0122] For general battery cells, a pressure relief structure is usually provided on the outer shell of the battery cell, so that the pressure relief structure can be cracked when the battery cell has thermal runaway to release the internal pressure of the battery cell, which is conducive to ensuring the safety of the battery cell. In the related art, in order to improve the structural strength and stability of the pressure relief structure set on the outer shell, an integrated molding process is usually used to form the pressure relief structure on the outer shell, such as a stamping process, so that a notched groove is set on the outer shell to form a pressure relief structure on the outer shell, and in order to facilitate the pressure relief of the pressure relief structure, the notched groove is usually set to an "H" or "Y" type structure, so that the area of ​​the outer shell surrounded by the notched groove can be flipped and opened after cracking along the notched groove, so as to increase the pressure relief area of ​​the battery cell. However, due to the thickness of the outer shell, even if the area of ​​the outer shell surrounded by the notch groove is cracked along the notch groove, it cannot be effectively flipped, so that the pressure relief area of ​​the battery cell is still small, resulting in a low pressure relief rate of the battery cell when thermal runaway occurs, making the battery cell have the risk of fire and explosion or connection failure due to untimely pressure relief, which in turn leads to low reliability of the battery cell.

[0123] Based on the above considerations, in order to solve the problem of low reliability of battery cells, an embodiment of the present application provides a battery cell, which includes a shell. The first wall is provided with a first groove, the first groove defines at least one predetermined pressure relief zone, and the first wall is configured to be able to split along at least part of the first groove when the battery cell is depressurized. The first wall is also provided with a second groove, the second groove and the first groove are arranged along a first direction, and the second groove is located on one side of the first groove in the first direction, the first direction is perpendicular to the thickness direction of the first wall, and the second groove is configured to guide at least part of the predetermined pressure relief zone to flip so as to open at least part of the predetermined pressure relief zone.

[0124] In a battery cell of this structure, by providing a first groove and a second groove on the first wall, and the first groove defines a predetermined pressure relief zone, the predetermined pressure relief zone can be opened after the first wall is split along at least part of the first groove, and can be turned around the position where the second groove is located to release the internal pressure of the battery cell, wherein, by arranging the first groove and the second groove in a structure arranged along the first direction, the second groove and the first groove are in a structure just in contact or arranged at intervals, so that the second groove is located on one side of the first groove in the first direction, on the one hand, the interference between the first groove and the second groove can be reduced, and the first groove and the second groove can be processed separately, and the phenomenon that the first groove tears the second groove when split can be alleviated, thereby facilitating the effect of turning the predetermined pressure relief zone around the second groove, and on the other hand, the effect of turning the predetermined pressure relief zone around the position where the second groove is located after being opened can be improved, so as to expand the turning angle of the predetermined pressure relief zone, thereby increasing the pressure relief area of ​​the battery cell, and improving the pressure relief rate of the battery cell when thermal runaway occurs, thereby reducing the risk of fire, explosion or connection failure of the battery cell due to untimely pressure relief, and facilitating the use reliability of the battery cell.

[0125] The battery cells disclosed in the embodiments of the present application can be used, but not limited to, in electrical devices such as vehicles, ships or aircraft. A power supply system comprising the battery cells and batteries disclosed in the present application can be used to form the electrical device, which is helpful to alleviate the problem of fire and explosion caused by untimely pressure relief of the battery cells, thereby improving the reliability of the battery cells.

[0126] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0127] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0128] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom of the vehicle 1000, or at the head of the vehicle 1000, or at the tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source or a power source for the vehicle 1000, etc. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for the starting, navigation and working power requirements of the vehicle 1000 during driving.

[0129] In some embodiments of the present application, the battery 100 can not only serve as an operating power source or a use power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0130] Please refer to Figure 2 and Figure 3 , Figure 2 The structure explosion diagram of the battery 100 provided in some embodiments of the present application is shown in FIG. Figure 3 The schematic diagram of the structure of the battery cell 20 provided in some embodiments of the present application. The battery 100 comprises a box body 10 and a battery cell 20 , and the battery cell 20 is used to be accommodated in the box body 10 .

[0131] The box body 10 is used to provide an assembly space for the battery cell 20, and the box body 10 can adopt a variety of structures. In some embodiments, the box body 10 may include a first box body 11 and a second box body 12, the first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cell 20. The second box body 12 may be a hollow structure with one end open, and the first box body 11 may be a plate-like structure, and the first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define an assembly space; the first box body 11 and the second box body 12 may also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0132] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid or a cube. Figure 2 In the embodiment, the box body 10 is in the shape of a rectangular parallelepiped.

[0133] In the battery 100, the battery cell 20 disposed in the box 10 may be one or more. When there are more than one battery cell 20 disposed in the box 10, the multiple battery cells 20 may be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in mixed connection, and then the whole formed by the multiple battery cells 20 may be accommodated in the box 10; of course, the battery 100 may also be a battery module formed by connecting multiple battery cells 20 in series, in parallel, or in mixed connection, and then the multiple battery modules may be connected in series, in parallel, or in mixed connection to form a whole, and then the whole may be accommodated in the box 10.

[0134] In some embodiments, the battery 100 may further include other structures. For example, the battery 100 may further include a busbar component, and the busbar component is used to connect the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0135] Each battery cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be in a rectangular parallelepiped, a cylinder, a prism or other shapes. For example, Figure 3 In the figure, the battery cell 20 is a rectangular parallelepiped structure.

[0136] According to some embodiments of the present application, referring to Figure 3 , and please refer to Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 , Figure 4 This is an exploded view of the structure of the battery cell 20 provided in some embodiments of the present application. Figure 5 This is a schematic diagram of the structure of the housing 212 of the housing 21 of the battery cell 20 provided in some embodiments of the present application. Figure 6 A bottom view of a housing 212 of a battery cell 20 provided in some embodiments of the present application, Figure 7 for Figure 6 A partial enlarged view of the housing 212 shown, Figure 8A partial cross-sectional view of a shell 212 of a battery cell 20 provided in some embodiments of the present application. The present application provides a battery cell 20, which includes a shell 21. The shell 21 includes a first wall 211. The first wall 211 is provided with a first groove 221, which defines at least one predetermined pressure relief zone 222, and the first wall 211 is configured to be able to split along at least part of the first groove 221 when the battery cell 20 is depressurized. The first wall 211 is also provided with a second groove 223, which is arranged along the first direction Y with the first groove 221, and the second groove 223 is located on one side of the first groove 221 in the first direction Y, and the first direction Y is perpendicular to the thickness direction X of the first wall, and the second groove 223 is configured to guide at least part of the predetermined pressure relief zone 222 to flip, so as to open at least part of the predetermined pressure relief zone 222.

[0137] Among them, see Figure 4 As shown, the battery cell 20 may further include an electrode assembly 23, which is accommodated in the outer shell 21. The electrode assembly 23 is a component in the battery cell 20 where an electrochemical reaction occurs. The structure of the electrode assembly 23 may be various. For example, the electrode assembly 23 may be a wound structure formed by winding a positive electrode sheet, an isolation member, and a negative electrode sheet, or may be a stacked structure formed by stacking a positive electrode sheet, an isolation member, and a negative electrode sheet.

[0138] Exemplarily, the isolation member is an isolation membrane, and a main material of the isolation membrane may be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0139] Optionally, the number of electrode assemblies 23 contained in the housing 21 may be one or more. Figure 4 In the embodiment, two electrode assemblies 23 are disposed in the housing 21 of the battery cell 20, and the two electrode assemblies 23 are stacked along the thickness direction thereof, that is, the two electrode assemblies 23 are stacked along the thickness direction of the battery cell 20. Of course, in other embodiments, the number of electrode assemblies 23 accommodated in the housing 21 may be one, three, four, five, six, seven or eight.

[0140] The housing 21 can also be used to contain electrolytes, such as electrolytes. The housing 21 can be in various structural forms, such as a cylinder, a cuboid, or a prism structure. Similarly, the housing 21 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy.

[0141] In some embodiments, the housing 21 may include a shell 212 and an end cap 213, wherein the shell 212 has a receiving cavity 2121 formed therein, the receiving cavity 2121 being used to receive the electrode assembly 23, and the receiving cavity 2121 having an opening 2122, that is, the shell 212 is a hollow structure with an opening 2122 at one end, and the end cap 213 covers the opening 2122 of the shell 212 and forms a sealed connection to form an enclosed space for receiving the electrode assembly 23 and the electrolyte.

[0142] It should be noted that the first wall 211 on which the first groove 221 and the second groove 223 are provided may be the end cover 213 of the housing 21 or a wall of the shell 212 of the housing 21. Figure 4 , Figure 5 and Figure 6 In the embodiment, the first wall 211 is a bottom wall of the shell 212 disposed opposite to the end cover 213 in the thickness direction X of the first wall. The shell 212 further includes a second wall 2123, a third wall 2124, a fourth wall 2125 and a fifth wall 2126 connected end to end in sequence, and one end of the second wall 2123, the third wall 2124, the fourth wall 2125 and the fifth wall 2126 in the thickness direction X of the first wall are connected to the first wall 211, and the other ends of the second wall 2123, the third wall 2124, the fourth wall 2125 and the fifth wall 2126 in the thickness direction X of the first wall are enclosed to form an opening 2122, so that the first wall 211, the second wall 212 3. The third wall 2124, the fourth wall 2125 and the fifth wall 2126 enclose a housing cavity 2121 for accommodating the electrode assembly 23, wherein the second wall 2123 and the third wall 2124 are arranged opposite to each other along the first direction Y, and the fourth wall 2125 and the fifth wall 2126 are arranged opposite to each other along the second direction Z, the second direction Z is perpendicular to the first direction Y and the thickness direction X of the first wall, the first direction Y is the width direction of the first wall 211, and is also the thickness direction of the battery cell 20, and the second direction Z is the length direction of the first wall 211. Of course, the structure of the battery cell 20 is not limited thereto, in other embodiments, the first wall 211 may also be the end cover 213, and the first wall 211 may also be the side wall of the housing 212 adjacent to and connected to the end cover 213.

[0143] When assembling the battery cell 20 , the electrode assembly 23 may be placed in the housing 212 first, and the housing 212 may be filled with electrolyte, and then the end cap 213 may be covered on the opening 2122 of the housing 212 to complete the assembly of the battery cell 20 .

[0144] The shell 212 can be in various shapes, such as a cylinder, a cuboid, or a prism structure. The shape of the shell 212 can be determined according to the specific shape of the electrode assembly 23. For example, if the electrode assembly 23 is a cylindrical structure, a shell 212 with a cylindrical structure can be selected; if the electrode assembly 23 is a cuboid structure, a shell 212 with a cuboid structure can be selected. Of course, the structure of the end cap 213 can also be various, such as the end cap 213 being a plate-like structure or a hollow structure with one end open. For example, in Figure 4 In the embodiment, the shell 212 is a rectangular parallelepiped structure, and the end cover 213 is a rectangular plate structure.

[0145] Of course, it is understandable that the outer shell 21 is not limited to the above structure, and the outer shell 21 may also be other structures. For example, the outer shell 21 may include a shell body 212 and two end caps 213. The shell body 212 is a hollow structure with openings 2122 on opposite sides. One end cap 213 corresponds to an opening 2122 of the shell body 212 and forms a sealed connection to form an enclosed space for accommodating the electrode assembly 23 and the electrolyte. That is, the shell body 212 is formed with openings 2122 on opposite sides, and the two end caps 213 are respectively covered on the two sides of the shell body 212 to close the corresponding openings 2122.

[0146] In some embodiments, see Figure 3 and Figure 4 As shown, the battery cell 20 may further include an electrode terminal 24 , which is insulated and mounted on the housing 21 , and is electrically connected to the electrode assembly 23 to output or input electrical energy of the battery cell 20 .

[0147] It should be noted that the electrode terminal 24 is insulated and mounted on the housing 21 , that is, no electrical connection is formed between the electrode terminal 24 and the housing 21 .

[0148] Among them, Figure 3 and Figure 4In the embodiment, the battery cell 20 includes two electrode terminals 24, which are arranged at intervals along the second direction Z. Correspondingly, each electrode assembly 23 has two pole ears 231, which are arranged at intervals along the second direction Z, and the polarities of the two pole ears 231 are opposite. The two electrode terminals 24 are electrically connected to the two pole ears 231 of the electrode assembly 23, respectively, so as to realize the input or output of the positive electrode and the negative electrode of the battery cell 20. It should be noted that the pole ears 231 of the electrode assembly 23 are components formed by mutually stacking and connecting the regions on the positive electrode sheet that are not coated with the positive electrode active material layer, or components formed by mutually stacking and connecting the regions on the negative electrode sheet that are not coated with the negative electrode active material layer. If the pole ears 231 are used to output the positive electrode of the electrode assembly 23, the pole ears 231 are components formed by mutually stacking and connecting the regions on the positive electrode sheet that are not coated with the positive electrode active material layer; if the pole ears 231 are used to output the negative electrode of the electrode assembly 23, the pole ears 231 are components formed by mutually stacking and connecting the regions on the negative electrode sheet that are not coated with the negative electrode active material layer.

[0149] Exemplarily, the electrode terminal 24 may be made of a variety of materials. For example, the electrode terminal 24 may be made of copper, iron, aluminum, steel, or aluminum alloy.

[0150] Optionally, the electrode terminal 24 may be mounted on the housing 21 in various structures. Figure 3 and Figure 4 In the embodiment, the two electrode terminals 24 are both mounted on the end cap 213 of the outer shell 21. Of course, the structure of the battery cell 20 is not limited thereto. In other embodiments, the two electrode terminals 24 may be both mounted on the shell 212 of the outer shell 21. Similarly, one electrode terminal 24 may be mounted on the shell 212 of the outer shell 21, and the other electrode terminal 24 may be mounted on the end cap 213 of the outer shell 21.

[0151] In some embodiments, see Figure 4 As shown, the battery cell 20 may also include two current collecting components 25, both of which are arranged in the outer shell 21, and each current collecting component 25 is used to connect an electrode terminal 24 and a plurality of electrode lugs 231 with the same polarity in the electrode assemblies 23 to achieve electrical connection between the electrode terminal 24 and the electrode assembly 23, which is beneficial to reduce the difficulty of assembly between the lug 231 and the electrode terminal 24.

[0152] Exemplarily, the material of the current collecting component 25 may be various, for example, the material of the current collecting component 25 may be copper, iron, aluminum, steel or aluminum alloy.

[0153] In the embodiment of the present application, the area where the first groove 221 is provided on the first wall 211 serves as a pressure relief in the battery cell 20 and is used to relieve the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

[0154] The first wall 211 is provided with a first groove 221, which serves the purpose of pressure relief. When the internal pressure or temperature of the battery cell 20 reaches a predetermined value, the first wall 211 can be split along the position where the first groove 221 is located, so as to open the predetermined pressure relief area 222 defined by the first groove 221 to release the pressure inside the battery cell 20.

[0155] The first groove 221 defines at least one predetermined pressure relief area 222, that is, at least one predetermined pressure relief area 222 is formed in the area where the first groove 221 is located. Figure 6 and Figure 7 In the embodiment, the first groove 221 defines two predetermined pressure relief areas 222, and the two predetermined pressure relief areas 222 are arranged at intervals along the first direction Y. The first groove 221 is a structure arranged along the edge of the predetermined pressure relief area 222, so that the arrangement trajectory of the first groove 221 is arranged along the edge of the predetermined pressure relief area 222, so that the first wall 211 can be split along the edge of the predetermined pressure relief area 222.

[0156] The first wall 211 is configured to be able to split along at least a portion of the first groove 221 when the battery cell 20 releases pressure. That is, when the battery cell 20 undergoes thermal runaway and releases internal pressure, the area of ​​the first wall 211 where the first groove 221 is provided can split, thereby allowing the predetermined pressure relief area 222 to be opened and release the internal pressure of the battery cell 20.

[0157] For example, see Figure 8 As shown, along the thickness direction X of the first wall, the first groove 221 is disposed on the side of the first wall 211 away from the inside of the housing 21, that is, the first groove 221 is disposed on the side of the first wall 211 away from the electrode assembly 23. Of course, in other embodiments, the first groove 221 may also be disposed on the side of the first wall 211 facing the inside of the housing 21, that is, the first groove 221 is disposed on the side of the first wall 211 facing the electrode assembly 23.

[0158] The first wall 211 is also provided with a second groove 223, and the second groove 223 and the first groove 221 are arranged along the first direction Y, and the second groove 223 is located on one side of the first groove 221 in the first direction Y, that is, the second groove 223 and the first groove 221 are structures arranged along the first direction Y, that is, in the first direction Y, the second groove 223 is arranged on at least one side of the first groove 221, and the second groove 223 can be a structure that is in contact with or spaced apart from the first groove 221.

[0159] For example, in Figure 6 and Figure 7In the figure, the first groove 221 defines two predetermined pressure relief areas 222 arranged at intervals along the first direction Y. Correspondingly, second grooves 223 are provided on both sides of the first groove 221 in the first direction Y, so that the first groove 221 is located between the two second grooves 223 in the first direction Y, and each predetermined pressure relief area 222 corresponds to a second groove 223.

[0160] The second groove 223 is configured to guide at least a portion of the predetermined pressure relief area 222 to flip over so as to open at least a portion of the predetermined pressure relief area 222. That is, after the first wall 211 is split along the first groove 221 and the predetermined pressure relief area 222 is opened, at least a portion of the predetermined pressure relief area 222 can be flipped around the bottom wall of the second groove 223 as an axis, so that after the predetermined pressure relief area 222 is flipped over, the interior of the outer shell 21 and the exterior of the outer shell 21 are connected to each other for pressure relief.

[0161] For example, see Figure 8 As shown, along the thickness direction X of the first wall, the second groove 223 is arranged on the side of the first wall 211 facing the inside of the housing 21, that is, the second groove 223 is arranged on the side of the first wall 211 facing the electrode assembly 23. Of course, in other embodiments, the second groove 223 can also be arranged on the side of the first wall 211 away from the inside of the housing 21, that is, the second groove 223 is arranged on the side of the first wall 211 away from the electrode assembly 23.

[0162] Exemplarily, the first groove 221 may be formed by a processing technique such as stamping or milling, and similarly, the second groove 223 may also be formed by a processing technique such as stamping or milling.

[0163] In some embodiments, along the thickness direction X of the first wall, the ratio of the maximum groove depth of the first groove 221 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 221 includes only one smooth groove segment in the embodiment, the maximum groove depth of the first groove 221 is the maximum depth of the groove segment; if the first groove 221 includes multiple smooth groove segments in the embodiment, the maximum groove depth of the first groove 221 is the maximum groove depth of the groove segment with the largest depth among the multiple groove segments.

[0164] Exemplarily, the ratio of the maximum groove depth of the first groove 221 in the thickness direction X of the first wall to the thickness of the first wall 211 in the thickness direction X of the first wall can be 0.16, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.62, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.82, 0.85, 0.88, 0.9, 0.92, 0.95, 0.98, 0.99, etc., or any point value or a range value between any two of them.

[0165] In some embodiments, along the thickness direction X of the first wall, the maximum groove depth of the first groove 221 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.

[0166] Along the thickness direction X of the first wall, the maximum groove depth of the first groove 221 can be 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, etc., any one of the point values ​​or any range value between two of them.

[0167] Along the thickness direction X of the first wall, the thickness of the first wall 211 can be any point value among 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, 2.05mm, 2.1mm, 2.15mm, 2.2mm, 2.25mm, 2.3mm, 2.35mm, 2.4mm, 2.45mm, 2.5mm, etc., or a range value between any two of them.

[0168] In this embodiment, the first groove 221 and the second groove 223 are provided on the first wall 211, and the first groove 221 defines a predetermined pressure relief area 222, so that the predetermined pressure relief area 222 can be opened after the first wall 211 is at least partially cracked along the first groove 221, and can be turned around the position where the second groove 223 is located to release the internal pressure of the battery cell 20, wherein, by arranging the first groove 221 and the second groove 223 in a structure arranged along the first direction Y, the second groove 223 and the first groove 221 are in a structure that is just in contact or arranged at intervals, so that the second groove 223 is located on one side of the first groove 221 in the first direction Y, on the one hand, the first groove 221 and the second groove can be reduced. The interference effect between the first groove 221 and the second groove 223 makes it easier to process the first groove 221 and the second groove 223 respectively, and can alleviate the phenomenon that the first groove 221 tears the second groove 223 when it is cracked, which is beneficial to improving the effect of the predetermined pressure relief area 222 flipping around the second groove 223. On the other hand, it can improve the effect of the predetermined pressure relief area 222 flipping around the position of the second groove 223 after being opened, so as to expand the flipping angle of the predetermined pressure relief area 222, thereby increasing the pressure relief area of ​​the battery cell 20, so as to improve the pressure relief rate of the battery cell 20 when thermal runaway occurs, and then can reduce the risk of fire, explosion or connection failure of the battery cell 20 due to untimely pressure relief, which is beneficial to improving the reliability of the battery cell 20.

[0169] According to some embodiments of the present application, see Figure 6 and Figure 7 As shown, along the first direction Y, the first groove 221 and the second groove 223 are arranged at intervals. That is, the orthographic projections of the first groove 221 and the second groove 223 in a plane perpendicular to the thickness direction X of the first wall are arranged at intervals along the first direction Y, so that along the first direction Y, the projection of the first groove 221 in the thickness direction X of the first wall and the projection of the second groove 223 in the thickness direction X of the first wall are arranged at intervals, that is, the second groove 223 is located on one side of the first groove 221 in the first direction Y, and there is a gap between the two.

[0170] For example, in Figure 7 In the embodiment, the first wall 211 is provided with two second grooves 223 , which are arranged at intervals along the first direction Y and are respectively located on both sides of the first groove 221 in the first direction Y. The two second grooves 223 and the first groove 221 are both arranged at intervals in the first direction Y.

[0171] In this embodiment, by setting the first groove 221 and the second groove 223 to a structure arranged at intervals along the first direction Y, the first groove 221 and the second groove 223 are not in contact with each other. On the one hand, the mutual influence between the first groove 221 and the second groove 223 during the processing can be reduced, and the stress influence between the area of ​​the first wall 211 where the first groove 221 is set and the area of ​​the first wall 211 where the second groove 223 is set can be reduced. On the other hand, the phenomenon of the first groove 221 tearing the second groove 223 when cracking can be further alleviated, which is beneficial to improving the effect of the predetermined pressure relief area 222 flipping around the second groove 223.

[0172] According to some embodiments of the present application, see Figure 7 As shown, along the first direction Y, the minimum distance between the projection of the first groove 221 in the thickness direction X of the first wall and the projection of the second groove 223 in the thickness direction X of the first wall is L 1 , meet, 0.1mm≤L 1 ≤4mm. That is, the minimum distance between the first groove 221 and the second groove 223 in the first direction Y is L 1 That is, the minimum gap between the first groove 221 and the second groove 223 has a size in the first direction Y of 0.1 mm to 4 mm.

[0173] Exemplarily, the minimum distance L between the projection of the first groove 221 in the thickness direction X of the first wall and the projection of the second groove 223 in the thickness direction X of the first wall is 1 It can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.5mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.5m or 4mm, etc.

[0174] It should be noted that in the embodiment where two second grooves 223 are provided on the first wall 211, and the two second grooves 223 are respectively located on both sides of the first groove 221 in the first direction Y, as shown in FIG. Figure 7 As shown, the minimum distance between the two second grooves 223 and the first groove 221 in the first direction Y is L 1 .

[0175] In this embodiment, by setting the minimum distance between the projection of the first groove 221 and the second groove 223 along the thickness direction X of the first wall in the first direction Y to 0.1 mm to 4 mm, the minimum distance between the first groove 221 and the second groove 223 in the first direction Y is 0.1 mm to 4 mm. On the one hand, the minimum distance between the projection of the first groove 221 and the second groove 223 along the thickness direction X of the first wall in the first direction Y is set to be greater than or equal to 0.1 mm, so as to reduce the interference effect between the first groove 221 and the second groove 223, which is conducive to reducing The difficulty of machining the first groove 221 and the second groove 223 on the first wall 211 can be reduced, and the phenomenon that the first groove 221 tears the second groove 223 when it is cracked can be further alleviated. On the other hand, the minimum distance between the projections of the first groove 221 and the second groove 223 along the thickness direction X of the first wall in the first direction Y is set to be less than or equal to 4 mm, so as to increase the angle at which the predetermined pressure relief zone 222 flips around the second groove 223 and the pressure relief area after the predetermined pressure relief zone 222 is opened, thereby further improving the pressure relief rate of the battery cell 20 when thermal runaway occurs.

[0176] In some embodiments, see Figure 7 As shown, along the first direction Y, the minimum distance between the projections of the first groove 221 and the second groove 223 along the thickness direction X of the first wall in the first direction Y is L 1 , meet, 0.2mm≤L 1 That is, the minimum gap between the first groove 221 and the second groove 223 has a size in the first direction Y of 0.2 mm to 2 mm.

[0177] In this embodiment, by setting the minimum distance between the projection of the first groove 221 and the second groove 223 along the thickness direction X of the first wall in the first direction Y to 0.2 mm to 2 mm, the minimum distance between the first groove 221 and the second groove 223 in the first direction Y is 0.2 mm to 2 mm. On the one hand, the minimum distance between the projection of the first groove 221 and the second groove 223 along the thickness direction X of the first wall in the first direction Y is further set to be greater than or equal to 0.2 mm, so as to further reduce the interference effect between the first groove 221 and the second groove 223, which is conducive to further reducing the difficulty of machining the first groove 221 and the second groove 223 on the first wall 211, and can further On the one hand, the phenomenon that the first groove 221 tears the second groove 223 when it is cracked is alleviated. On the other hand, the minimum distance between the projections of the first groove 221 and the second groove 223 along the thickness direction X of the first wall in the first direction Y is set to be less than or equal to 2 mm, so as to further increase the angle at which the predetermined pressure relief zone 222 is turned around the second groove 223 and the pressure relief area after the predetermined pressure relief zone 222 is opened, so as to further improve the pressure relief rate of the battery cell 20 when thermal runaway occurs, so that the battery cell 20 can improve the effect of turning around the position where the second groove 223 is located after the predetermined pressure relief zone 222 is opened while alleviating the synchronous tearing of the second groove 223 by the first groove 221.

[0178] According to some embodiments of the present application, see Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, the housing 21 may further include a second wall 2123 and a third wall 2124 that are arranged opposite to each other along the first direction Y. The first wall 211 connects the second wall 2123 and the third wall 2124. Along the first direction Y, the second wall 2123 has a first outer surface 2123a that faces away from the interior of the housing 21, and the third wall 2124 has a second outer surface 2124a that faces away from the interior of the housing 21. Along the first direction Y, a second groove 223 is provided between the first groove 221 and the first outer surface 2123a.

[0179] Among them, the shell 21 can also include a second wall 2123 and a third wall 2124 relatively arranged along the first direction Y, that is, the second wall 2123 and the third wall 2124 of the shell 21 are structures arranged at intervals along the first direction Y. Exemplarily, the shell 21 is a rectangular structure, and correspondingly, the second wall 2123 and the third wall 2124 are two walls of the shell 21 relatively arranged in the first direction Y, and the thickness direction of the second wall 2123 and the thickness direction of the third wall 2124 are both the first direction Y.

[0180] The first wall 211 connects the second wall 2123 and the third wall 2124 , that is, two ends of the first wall 211 in the first direction Y are connected to the second wall 2123 and the third wall 2124 , respectively.

[0181] Along the first direction Y, the second groove 223 is disposed between the first groove 221 and the first outer surface 2123a, that is, the first outer surface 2123a, the second groove 223 and the first groove 221 are sequentially arranged along the first direction Y. Figure 7 In the embodiment, the first outer surface 2123a, the second groove 223 and the first groove 221 are all arranged at intervals along the first direction Y.

[0182] In the present embodiment, when the second groove 223 is provided between the first groove 221 and the first outer surface 2123a of the second wall 2123, the second groove 223 is closer to the first outer surface 2123a of the second wall 2123 than the first groove 221, so that the rigidity of the position where the second groove 223 is provided on the first wall 211 is greater than the rigidity of the position where the first groove 221 is provided on the first wall 211, so that when the internal pressure of the battery cell 20 is released, the deformation of the first wall 211 at the position where the first groove 221 is located is greater than the deformation of the first wall 211 at the position where the second groove 223 is located, which is conducive to the area where the first groove 221 of the first wall 211 is provided to crack and release the internal pressure of the battery cell 20 in priority to the area where the second groove 223 of the first wall 211 is provided. On the one hand, it can alleviate the phenomenon that the first wall 211 cracks from the area where the second groove 223 is provided, resulting in poor pressure relief effect of the battery cell 20, and on the other hand, it can achieve that the predetermined pressure relief area 222 is stably flipped open under the guidance of the groove bottom wall of the second groove 223.

[0183] In some embodiments, see Figure 6 , Figure 7 and Figure 8 As shown, a second groove 223 may also be provided between the first groove 221 and the second outer surface 2124a along the first direction Y. That is, the second outer surface 2124a, the second groove 223 and the first groove 221 are arranged in sequence along the first direction Y.

[0184] For example, in Figure 7 In the embodiment, the second outer surface 2124a, the second groove 223 and the first groove 221 are all arranged at intervals along the first direction Y.

[0185] For example, in Figure 6 and Figure 7In the figure, along the first direction Y, second grooves 223 are provided between the first groove 221 and the first outer surface 2123a and between the first groove 221 and the second outer surface 2124a, that is, the first wall 211 is provided with two second grooves 223 arranged at intervals along the first direction Y, and the first groove 221 is located between the two second grooves 223, so that the two second grooves 223 are respectively located on both sides of the first groove 221.

[0186] In the present embodiment, when the second groove 223 is provided between the first groove 221 and the second outer surface 2124a of the third wall 2124, the second groove 223 is closer to the second outer surface 2124a of the third wall 2124 than the first groove 221, so that the rigidity of the position where the second groove 223 is provided on the first wall 211 is greater than the rigidity of the position where the first groove 221 is provided on the first wall 211, so that when the internal pressure of the battery cell 20 is released, the deformation of the first wall 211 at the position where the first groove 221 is located is greater than the deformation of the first wall 211 at the position where the second groove 223 is located, which is conducive to the area where the first groove 221 of the first wall 211 is provided to crack and release the internal pressure of the battery cell 20 in priority to the area where the second groove 223 of the first wall 211 is provided. On the one hand, it can alleviate the phenomenon that the first wall 211 cracks from the area where the second groove 223 is provided, resulting in poor pressure relief effect of the battery cell 20, and on the other hand, it can achieve that the predetermined pressure relief area 222 is stably flipped open under the guidance of the groove bottom wall of the second groove 223.

[0187] According to some embodiments of the present application, see Figure 8 As shown, along the thickness direction X of the first wall, the first wall 211 has a third outer surface 2111 away from the interior of the housing 21, and the third outer surface 2111 is connected to the first outer surface 2123a through the first arc surface 214. Along the first direction Y, the second groove 223 is located between the first arc surface 214 and the first groove 221.

[0188] Among them, the third outer surface 2111 is connected to the first outer surface 2123a through the first arc surface 214, that is, the position where the third outer surface 2111 of the first wall 211 and the first outer surface 2123a of the second wall 2123 are connected to each other is a circular arc transition structure, so that a first arc surface 214 is formed between the third outer surface 2111 of the first wall 211 and the first outer surface 2123a of the second wall 2123, so that a rounded corner structure is formed between the first wall 211 and the second wall 2123.

[0189] Along the first direction Y, the second groove 223 is located between the first arc surface 214 and the first groove 221 , that is, the first arc surface 214 , the second groove 223 and the first groove 221 are sequentially arranged along the first direction Y.

[0190] For example, in Figure 8 In the embodiment, the first arc surface 214 and the second groove 223 are arranged at intervals along the first direction Y.

[0191] In this embodiment, the second groove 223 is arranged between the first groove 221 and the first arc surface 214 in the first direction Y so that the second groove 223 does not contact the corner of the outer shell 21, thereby reducing the influence of the stress at the corner of the outer shell 21 on the area where the second groove 223 is located, and can reduce the processing difficulty of the second groove 223.

[0192] According to some embodiments of this application, please continue to refer to Figure 8 As shown, along the thickness direction X of the first wall, the first wall 211 has a third outer surface 2111 away from the interior of the housing 21, and the third outer surface 2111 is connected to the second outer surface 2124a through the second arc surface 215. Along the first direction Y, the second groove 223 is located between the second arc surface 215 and the first groove 221.

[0193] Among them, the third outer surface 2111 is connected to the second outer surface 2124a through the second arc surface 215, that is, the position where the third outer surface 2111 of the first wall 211 and the second outer surface 2124a of the third wall 2124 are connected to each other is a circular arc transition structure, so that a second arc surface 215 is formed between the third outer surface 2111 of the first wall 211 and the second outer surface 2124a of the third wall 2124, so that a rounded corner structure is formed between the first wall 211 and the third wall 2124.

[0194] Along the first direction Y, the second groove 223 is located between the second arc surface 215 and the first groove 221 , that is, the second arc surface 215 , the second groove 223 and the first groove 221 are sequentially arranged along the first direction Y.

[0195] For example, in Figure 8 In the embodiment, the second arc surface 215 and the second groove 223 are arranged at intervals along the first direction Y.

[0196] In this embodiment, the second groove 223 is arranged between the first groove 221 and the second arc surface 215 in the first direction Y so that the second groove 223 does not contact the corner of the outer shell 21, thereby reducing the influence of the stress at the corner of the outer shell 21 on the area where the second groove 223 is located, and can reduce the processing difficulty of the second groove 223.

[0197] According to some embodiments of the present application, see Figure 6 and Figure 7 As shown, along the first direction Y, the minimum distance L from the first groove 221 to the first outer surface 2123a is 2The minimum distance L from the first groove 221 to the second outer surface 2124a 3 The difference between the first groove 221 and the first outer surface 2123a is greater than or equal to 0, and the minimum distance L between the first groove 221 and the first outer surface 2123a is 2 The minimum distance L from the first groove 221 to the second outer surface 2124a 3 The difference between the first outer surface 2123a and the second outer surface 2124a is less than or equal to 0.1 times the distance D between the first outer surface 2123a and the second outer surface 2124a, that is, L 2 and L 3 The difference obtained by subtracting the smaller one from the larger one is greater than or equal to 0 and less than or equal to 0.1 times of D. That is, along the first direction Y, the distance between the first outer surface 2123a and the second outer surface 2124a is D, and the minimum distance between the first groove 221 and the first outer surface 2123a is L. 2 , the minimum distance between the first groove 221 and the second outer surface 2124a is L 3 , satisfying, 0≤|L 2 -L 3 | / D≤0.1.

[0198] Wherein, D represents the distance between the first outer surface 2123a and the second outer surface 2124a in the first direction Y, and is also the thickness of the outer shell 21 of the battery cell 20 in the first direction Y. During measurement, multiple measurements may be performed to obtain an average value.

[0199] L 2 represents the minimum distance between the first groove 221 and the first outer surface 2123a, that is, the minimum distance between the projection of the first groove 221 in the plane perpendicular to the thickness direction X of the first wall and the first outer surface 2123a is L 2 During measurement, the distance between the position of the first groove 221 closest to the first outer surface 2123a in the first direction Y and the first outer surface 2123a may be measured, and multiple measurements may be taken to obtain an average value to reduce measurement errors.

[0200] L 3 represents the minimum distance between the first groove 221 and the second outer surface 2124a. The minimum distance between the projection of the first groove 221 in the plane perpendicular to the thickness direction X of the first wall and the second outer surface 2124a is L. 3 During measurement, the distance between the position of the first groove 221 closest to the second outer surface 2124a in the first direction Y and the second outer surface 2124a may be measured, and multiple measurements may be taken to obtain an average value to reduce measurement errors.

[0201] |L 2 -L 3| / D represents the ratio of the difference between the minimum distance between the first groove 221 and the first outer surface 2123a along the first direction Y and the minimum distance between the first groove 221 and the second outer surface 2124a along the first direction Y to the distance between the first outer surface 2123a and the second outer surface 2124a.

[0202] 0≤|L 2 -L 3 | / D≤0.1 indicates that the distance between the first groove 221 and the first outer surface 2123a and the distance between the first groove 221 and the second outer surface 2124a are slightly different, that is, the first groove 221 is approximately located at the center of the first wall 211 in the first direction Y.

[0203] |L 2 -L 3 The value of | / D can be: 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09 or 0.1, etc.

[0204] In this embodiment, by setting the minimum distance L between the first groove 221 and the first outer surface 2123a 2 and the minimum distance L between the first groove 221 and the second outer surface 2124a 3 The difference is set to a ratio of the distance D between the first outer surface 2123a and the second outer surface 2124a to be between 0 and 0.1, so that the first groove 221 is located in the middle area of ​​the first wall 211 in the first direction Y, which is conducive to alleviating the phenomenon that the first groove 221 deviates excessively from the center position of the first wall 211 in the first direction Y. On the one hand, it is convenient to set the second groove 223 on one side of the first groove 221 along the first direction Y, which is conducive to reducing the difficulty of setting the second groove 223 on the first wall 211. On the other hand, it makes it easier to crack the area of ​​the first wall 211 where the first groove 221 is set for pressure relief, so that under the same bursting pressure, the residual thickness of the area of ​​the first wall 211 where the first groove 221 is set can be increased to improve the fatigue resistance of the first wall 211, thereby effectively improving the service life and reliability of the battery cell 20.

[0205] In some embodiments, along the first direction Y, the minimum distance between the first groove 221 and the first outer surface 2123a is L 2 , meet, 2mm≤L 2 ≤12mm.

[0206] For example, the minimum distance L between the first groove 221 and the first outer surface 2123a in the first direction Y is 2It can be 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, 10.5mm, 11mm, 11.5mm or 12mm, etc.

[0207] In this embodiment, by setting the minimum distance between the first groove 221 and the first outer surface 2123a to 2 mm to 12 mm, on the one hand, the minimum distance between the first groove 221 and the first outer surface 2123a is set to be greater than or equal to 2 mm to alleviate the difficulty in setting the second groove 223 between the first groove 221 and the first outer surface 2123a due to the small spacing between the first groove 221 and the first outer surface 2123a, and can reduce the stress concentration phenomenon; on the other hand, the minimum distance between the first groove 221 and the first outer surface 2123a is set to be less than or equal to 12 mm to reduce the space waste between the first groove 221 and the first outer surface 2123a, thereby alleviating the phenomenon that the area of ​​the first wall 211 where the first groove 221 is set is limited, which is beneficial to increase the area of ​​the first wall 211 used to set the first groove 221.

[0208] In some embodiments, along the first direction Y, the minimum distance between the first groove 221 and the second outer surface 2124a is L 3 , meet, 2mm≤L 3 ≤12mm.

[0209] For example, the minimum distance L between the first groove 221 and the second outer surface 2124a in the first direction Y is 3 It can be 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, 10.5mm, 11mm, 11.5mm or 12mm, etc.

[0210] In this embodiment, by setting the minimum distance between the first groove 221 and the second outer surface 2124a to 2 mm to 12 mm, on the one hand, the minimum distance between the first groove 221 and the second outer surface 2124a is set to be greater than or equal to 2 mm to alleviate the difficulty in setting the second groove 223 between the first groove 221 and the second outer surface 2124a due to the small spacing between the first groove 221 and the second outer surface 2124a, and can reduce the stress concentration phenomenon. On the other hand, the minimum distance between the first groove 221 and the second outer surface 2124a is set to be less than or equal to 12 mm to reduce the space waste between the first groove 221 and the second outer surface 2124a, thereby alleviating the phenomenon that the area of ​​the first wall 211 where the first groove 221 is set is limited, which is beneficial to increase the area of ​​the first wall 211 used to set the first groove 221.

[0211] According to some embodiments of the present application, referring to Figure 6 , Figure 7 and Figure 8 , and please refer to Fig. 9 , Fig. 9 for Figure 8 The enlarged partial view of the B portion of the housing 212 is shown. Along the first direction Y, the minimum distance L between the second groove 223 and the first outer surface 2123a is 4 The minimum distance L from the second groove 223 to the second outer surface 2124a 5 The difference between the first outer surface 2123a and the second outer surface 2124a is greater than or equal to 0.4 times the distance D between the first outer surface 2123a and the second outer surface 2124a, that is, L 4 and L 5 The difference obtained by subtracting the smaller one from the larger one is greater than or equal to 0.4 times of D. That is, along the first direction Y, the distance between the first outer surface 2123a and the second outer surface 2124a is D, and the minimum distances from the second groove 223 to the first outer surface 2123a and the second outer surface 2124a are L respectively. 4 and L 5 , satisfying,|L 5 -L 4 | / D≥0.4. The first weak portion 224 is formed at the bottom of the first groove 221. The first wall 211 is configured to be able to split along at least part of the first weak portion 224 when the battery cell 20 is depressurized. The first weak portion 224 includes at least one weak section 2241. The second weak portion 225 is formed at the bottom of the second groove 223. The cross-sectional area S of the second weak portion 225 perpendicular to its extension direction is 2 Greater than the cross-sectional area S of the weak section 2241 perpendicular to its extension direction 1 0.7 times of the cross-sectional area S of the second weak portion 225 perpendicular to its extension direction2 Less than or equal to the cross-sectional area S of the weak section 2241 perpendicular to its extension direction 1 That is, the cross-sectional area of ​​the weak section 2241 perpendicular to its extension direction is S 1 The cross-sectional area of ​​the second weak portion 225 perpendicular to its extension direction is S 2 , satisfying, 0.7<S 2 / S 1 ≤1.5.

[0212] Among them, L 4 represents the minimum distance between the second groove 223 and the first outer surface 2123a, that is, the minimum distance between the projection of the second groove 223 in the plane perpendicular to the thickness direction X of the first wall and the first outer surface 2123a is L 4 During measurement, the distance between the position of the second groove 223 closest to the first outer surface 2123a and the first outer surface 2123a may be measured, and a method of taking an average value through multiple measurements may be adopted to reduce measurement errors.

[0213] L 5 L represents the minimum distance between the second groove 223 and the second outer surface 2124a, that is, the minimum distance between the projection of the second groove 223 in the plane perpendicular to the thickness direction X of the first wall and the second outer surface 2124a is L 5 During measurement, the distance between the position of the second groove 223 closest to the second outer surface 2124a and the second outer surface 2124a may be measured, and a method of taking an average value through multiple measurements may be adopted to reduce measurement errors.

[0214] It should be noted that see Figure 8 As shown, in the embodiment where two second grooves 223 are provided on the first wall 211, the minimum distance between any second groove 223 and the first outer surface 2123a in the first direction Y is L. 4 , and the minimum distance between any second groove 223 and the second outer surface 2124a in the first direction Y is L 5 .

[0215] |L 5 -L 4 | / D represents the ratio of the difference between the minimum distance between the second groove 223 and the first outer surface 2123a in the first direction Y and the minimum distance between the second groove 223 and the second outer surface 2124a in the first direction Y to the distance between the first outer surface 2123a and the second outer surface 2124a.

[0216] |L 5 -L 4| / D≥0.4 indicates that the distance between the second groove 223 and the first outer surface 2123a in the first direction Y and the distance between the second groove 223 and the second outer surface 2124a in the first direction Y are greatly different, that is, the second groove 223 is arranged away from the center position of the first wall 211 in the first direction Y, so that the second groove 223 is close to the first outer surface 2123a or the second outer surface 2124a. It should be noted that |L 5 -L 4 The value of | / D is less than 1. For example, |L 5 -L 4 The value of | / D can be 0.4, 0.42, 0.45, 0.5, 0.55, 0.56, 0.6, 0.64, 0.65, 0.7, 0.75, 0.8, 0.85, 039, 0.91 or 0.95, etc.

[0217] A first weak portion 224 is formed at the bottom of the first groove 221, and the first wall 211 is configured to be able to split along at least part of the first weak portion 224 when the battery cell 20 releases pressure. That is, the first wall 211 is provided with a position of the first groove 221 and the portion corresponding to the bottom surface of the first groove 221 is the first weak portion 224, that is, the bottom wall of the first groove 221 is the first weak portion 224, so that the first wall 211 can split along the position where the bottom surface of the first groove 221 is located to release the internal pressure of the battery cell 20.

[0218] The first weak portion 224 includes at least one weak section 2241. It should be noted that the weak section 2241 of the first weak portion 224 is a structure extending along a smooth trajectory, such as a structure extending along a straight line or an arc. The weak section 2241 of the first weak portion 224 can be one or more. If the first weak portion 224 is a straight line structure, an arc structure or an annular structure, the first weak portion 224 only includes one weak section 2241. If the first weak portion 224 is a "V"-shaped structure, a "U"-shaped structure or an "H"-shaped structure, the first weak portion 224 includes multiple weak sections 2241. Exemplarily, a first groove 221 is provided on the first wall 211, and a first weak portion 224 is formed at the bottom of the first groove 221. The first groove 221 includes a first groove section 2211 and two second groove sections 2212. The two second groove sections 2212 are spaced apart and arranged opposite to each other along the second direction Z. The two ends of the first groove section 2211 in the second direction Z are respectively connected to the two second groove sections 2212. Then, the bottom of the first groove section 2211 and the bottom of the second groove section 2212 both form a weak section 2241 of the first weak portion 224, so that the first weak portion 224 includes three weak sections 2241.

[0219] The cross-sectional area of ​​the weak section 2241 perpendicular to its extension direction is S 1, that is, the cross-sectional area of ​​the bottom wall of any groove section of the first groove 221 in its extending direction is S 1 , that is, S 1 is the product of the width of the bottom surface of any groove section of the first groove 221 and the thickness of the bottom wall of the corresponding groove section. In some embodiments, the position of the weak section 2241 of the first weak portion 224 can be determined by tomography, and the cross-sectional area of ​​the cross section perpendicular to the extension direction of the weak section 2241 can be determined, that is, S can be obtained by tomography. 1 It should be noted that the groove bottom surface of the first groove 221 and the groove side surface of the first groove 221 may be directly connected or indirectly connected. For example, the groove bottom surface of the first groove 221 and the groove side surface of the first groove 221 may be connected through an arc chamfered surface. In other words, an arc chamfer is formed between the groove bottom surface of the first groove 221 and the groove side surface of the first groove 221. If the groove bottom surface of the first groove 221 and the groove side surface of the first groove 221 are indirectly connected, then S 1 It is the product of the width of the bottom surface of any groove section of the first groove 221 and the thickness of the area of ​​the first wall 211 corresponding to the bottom surface of the first groove 221, that is, the bottom surface of the first groove 221 does not include the arc chamfered surface formed between the bottom surface of the first groove 221 and the groove side surface of the first groove 221.

[0220] The second weak portion 225 is formed at the bottom of the second groove 223 , that is, the first wall 211 is provided with a position for the second groove 223 and the portion corresponding to the groove bottom surface of the second groove 223 is the second weak portion 225 , that is, the groove bottom wall of the second groove 223 is the second weak portion 225 .

[0221] For example, in Figure 7 and Figure 8 In the embodiment, the second groove 223 is a straight line structure extending along the second direction Z, and correspondingly, the second weak portion 225 is a straight line structure extending along the second direction Z.

[0222] The cross-sectional area of ​​the second weak portion 225 perpendicular to its extension direction is S 2 , that is, the cross-sectional area of ​​the bottom wall of the second groove 223 in its extending direction is S 2 , that is, S 2 is the product of the width of the bottom surface of the second groove 223 and the thickness of the bottom wall of the second groove 223. In some embodiments, the position of the second weak portion 225 can be determined by tomography, and the cross-sectional area of ​​the cross section perpendicular to the extension direction of the second weak portion 225 can be determined, that is, S can be obtained by tomography. 2It should be noted that the groove bottom surface of the second groove 223 and the groove side surface of the second groove 223 may be directly connected or indirectly connected. For example, the groove bottom surface of the second groove 223 and the groove side surface of the second groove 223 may be connected through an arc chamfered surface. In other words, an arc chamfer is formed between the groove bottom surface of the second groove 223 and the groove side surface of the second groove 223. If the groove bottom surface of the second groove 223 and the groove side surface of the second groove 223 are indirectly connected, then S 2 It is the product of the width of the bottom surface of the second groove 223 and the thickness of the bottom wall of the second groove 223, that is, the bottom surface of the second groove 223 does not include the arc chamfered surface formed between the bottom surface of the second groove 223 and the groove side surface of the second groove 223.

[0223] For S 1 and S 2 The risk that the second weak portion 225 breaks before the first weak portion 224 when the battery cell 20 is depressurized can be reduced.

[0224] When |L 5 -L 4 | / D≥0.4, S 2 / S 1 The value of can be: 0.71, 0.75, 0.78, 0.8, 0.83, 0.85, 0.9, 0.93, 0.95, 1, 1.05, 1.11, 1.12, 1.15, 1.17, 1.2, 1.24, 1.25, 1.3, 1.35, 1.38, 1.4, 1.44, 1.47 or 1.5, etc.

[0225] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail in conjunction with Comparative Examples 1-4 and Examples 1-10. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0226] Comparative Example 1

[0227] 1) Preparation of positive electrode

[0228] The positive electrode active material LiNi 0.7 Co 0.1 Mn 0.1 O 2, conductive agent Super P, and binder polyvinylidene fluoride (PVDF) are used to prepare positive electrode slurry in N-methylpyrrolidone (NMP), wherein the solid content in the positive electrode slurry is 50wt%, and the solid content of LiNi 0.7 Co 0.1 Mn 0.1 O 2 The mass ratio of 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 into pieces, and divided into strips, and then dried at 85°C under vacuum conditions for 4 hours to make the positive electrode sheet.

[0229] 2) Preparation of negative electrode

[0230] Graphite, conductive agent Super P, thickener carboxymethyl cellulose (CMC), and adhesive styrene butadiene rubber (SBR) are mixed evenly in deionized water to prepare a negative electrode slurry, wherein the solid content in the negative electrode slurry is 30wt%, and the mass ratio of graphite, silicon oxide, Super P, CMC and adhesive styrene butadiene rubber (SBR) in the solid component is 88:7:3:2. The negative electrode slurry is coated on the upper and lower surfaces of the current collector copper foil and dried at 85°C, and then cold pressed, trimmed, cut into pieces, and slit, and then dried at 120°C under vacuum conditions for 12 hours to prepare a negative electrode sheet.

[0231] 3) Preparation of electrolyte

[0232] In an argon atmosphere glove box (H 2 O<0.1ppm, O 2 <0.1ppm), the fully dried electrolyte salt LiPF 6 The electrolyte 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 uniform mixing, a liquid electrolyte with a concentration of 1 mol / L was obtained.

[0233] 4) Isolation parts

[0234] A 16 μm polyethylene film was used as a separator.

[0235] 5) Preparation of battery cell 20

[0236] The positive electrode sheet, the separator, and the negative electrode sheet are stacked in order, and the separator is placed in the middle of the positive and negative electrode sheets to separate the positive and negative electrodes. The electrode assembly 23 is wound and placed in an aluminum shell 21. The prepared electrolyte is injected into the dried shell 21, and the battery cell 20 is prepared by packaging, standing, forming, shaping, and capacity testing. A first groove 221 and a second groove 223 are set on the first wall 211 of the shell 21 of the battery cell 20 to form a first weak portion 224 at the bottom of the first groove 221 and a second weak portion 225 at the bottom of the second groove 223. Among them, the shell 21 of the battery cell 20 of comparative example 1 is a rectangular parallelepiped structure, and the first groove 221 is an "H"-shaped structure, that is, the first groove 221 includes a first groove section 2211 and two second groove sections 2212 (that is, the bottom of the first groove section 2211 and the bottom of the two second groove sections 2212 both form a weak section 2241, so that the first weak portion 224 formed at the bottom of the first groove 221 includes three interconnected weak sections 2241), the two second groove sections 2212 both extend along the first direction Y, and the two second groove sections 2212 are 2212 are relatively arranged along the second direction Z, the first groove segment 2211 extends along the second direction Z, and the two ends of the first groove segment 2211 in the second direction Z are respectively connected to two second groove segments 2212, the first groove segment 2211 is located at the center of the first wall 211 in the first direction Y, the shell 21 of the battery cell 20 has a thickness of 39mm in the first direction Y, a length of 203mm in the second direction Z, a height of 122.7mm in the thickness direction X of the first wall, and a capacity of the battery cell 20 is 185Ah.

[0237] The preparation methods of the battery cells 20 of Comparative Examples 2-4 and Examples 1-10 are the same as those of Comparative Example 1, except that the minimum distance L between the second groove 223 and the first outer surface 2123a in the first direction Y is 4 and a minimum distance L between the second groove 223 and the second outer surface 2124a in the first direction Y. 5 The difference is different, and the cross-sectional area S of the weak section 2241 of the first weak portion 224 perpendicular to its extension direction is 1 and the area S of the cross section of the second weak portion 225 perpendicular to its extending direction 2 different, so that the battery cell 20 | L 5 -L 4 | / D≥0.4, the area S of the cross section of the first wall 211 perpendicular to the extension direction of the second weak portion 225 is tested. 2 The area S of the cross section of the weak section 2241 of the first weak portion 224 perpendicular to the extension direction thereof is 1 The detonation conditions when the pressure is released under different ratios are shown in Tables 1 and 2. Specifically, in Table 1, |L5 -L 4 | / D=0.4, Table 2 shows |L 5 -L 4 | / D=0.56.

[0238] The battery cell 20 needs to be pre-processed before testing:

[0239] (1) Drilling a hole at the injection hole of the battery cell 20;

[0240] (2) Insert the hose into the battery cell 20 by 10 mm from the injection hole;

[0241] (3) Squeeze AB glue onto cardboard and mix evenly;

[0242] (4) Apply the evenly mixed AB glue around the interface between the hose and the battery cell 20 (Note: there should be no bubbles or dirt on the bonding surface) and let it stand for 30 minutes.

[0243] During the blasting experiment, a steel clamp is used to clamp the two sides of the outer shell 21 of the battery cell 20 along the first direction Y, that is, the first outer surface 2123a and the second outer surface 2124a of the outer shell 21 of the battery cell 20 are clamped with a steel clamp, and the preload force is 3000N, simulating the restraint state of the battery cell 20 in the actual battery 100; at the same time, during the experiment, the first wall 211 is photographed throughout the whole process to observe its detonation position and the predetermined pressure relief part flipping action. Before the experiment, the detonation pressure test system and the battery cell 20 are connected through a hose; during the experiment, the detonation pressure test system inflates and blasts the battery cell 20 at 0.3MPa / s, and detects the intake pressure of the battery cell 20 in real time. When the intake pressure drops by more than 0.02MPa, the inflation is stopped. In general, the intake pressure curve generally shows an increasing trend. When the intake pressure reaches the detonation pressure of the battery cell 20, it will suddenly drop to 0. At this time, the maximum value of the curve is the detonation pressure of the battery cell 20.

[0244] The experimental results of Comparative Examples 1-4 and Examples 1-10 are shown in Tables 1 and 2 below:

[0245] Table 1

[0246] Serial number <![CDATA[|L 5 -L 4 |]]> D <![CDATA[|L 5 -L 4 | / D]]> <![CDATA[S 1 ]]> <![CDATA[S 2 ]]> <![CDATA[S 2 / S 1 ]]> Detonation location Detonation pressure Comparative Example 1 15.6mm 39mm 0.4 <![CDATA[0.13mm 2 ]]> <![CDATA[0.09mm 2 ]]> 0.69 Second weak point 225 / Example 1 15.6mm 39mm 0.4 <![CDATA[0.14mm 2 ]]> <![CDATA[0.1mm 2 ]]> 0.71 First weak part 224 0.73MPa Example 2 15.6mm 39mm 0.4 <![CDATA[0.18mm 2 ]]> <![CDATA[0.15mm 2 ]]> 0.83 First weak part 224 0.83MPa Example 3 15.6mm 39mm 0.4 <![CDATA[0.2mm 2 ]]> <![CDATA[0.2mm 2 ]]> 1.00 First weak part 224 0.88MPa Example 4 15.6mm 39mm 0.4 <![CDATA[0.16mm 2 ]]> <![CDATA[0.22mm 2 ]]> 1.38 First weak part 224 0.99MPa Example 5 15.6mm 39mm 0.4 <![CDATA[0.12mm 2 ]]> <![CDATA[0.18mm 2 ]]> 1.5 First weak part 224 1.08MPa Comparative Example 2 15.6mm 39mm 0.4 <![CDATA[0.11mm 2 ]]> <![CDATA[0.17mm 2 ]]> 1.55 First weak part 224 1.11MPa

[0247] Table 2

[0248]

[0249]

[0250] Please refer to Table 1 and Table 2, and combine Comparative Example 1 and Comparative Example 3 to know that |L 5 -L 4| / D ≥ 0.4, but S 2 / S 1 ≤0.7, at this time, the cross-sectional area of ​​the second weak portion 225 formed at the bottom of the second groove 223 perpendicular to its extension direction is small. When the battery cell 20 is depressurized, the second weak portion 225 formed at the bottom of the second groove 223 will crack before the first weak portion 224 formed at the bottom of the first groove 221.

[0251] Combining Comparative Examples 3 and 4, it can be seen that |L 5 -L 4 | / D ≥ 0.4, but S 2 / S 1 >1.5. At this time, the cross-sectional area of ​​the second weak portion 225 formed at the bottom of the second groove 223 perpendicular to its extension direction is relatively large, so that the rigidity of the second weak portion 225 formed at the bottom of the second groove 223 is relatively large, and the obstacle to the predetermined pressure relief zone 222 flipping open is relatively large, so that it is difficult for the predetermined pressure relief zone 222 to flip around the second weak portion 225 after the first weak portion 224 is cracked, which can easily cause a large detonation pressure, so that the battery cell 20 has the phenomenon of untimely pressure relief, which can easily lead to the risk of bursting or explosion of the outer shell 21 of the battery cell 20. In the project, it is expected that the detonation position of the first wall 211 is located at the first weak portion 224, and the second weak portion 225 only serves to guide the predetermined pressure relief zone 222 to flip. When the battery cell 20 is used in the project, there is an upper and lower limit requirement for the detonation pressure (0.9±0.2MPa), so that in |L 5 -L 4 | / D≥0.4, if S 2 / S 1 >1.5, the detonation pressure will be higher than the upper limit of the detonation pressure desired by the project.

[0252] Combining Examples 1-5 and 6-10, it can be seen that |L 5 -L 4 | / D≥0.4, and 0.7<S 2 / S 1 ≤1.5, not only can the detonation position of the first wall 211 be located at the first weak portion 224, but the detonation pressure can also meet the engineering expectations. 5 -L 4 | / D≥0.4, the area S of the cross section of the second weak portion 225 perpendicular to its extension direction 2 The area S of the cross section of the weak section 2241 of the first weak portion 224 perpendicular to the extension direction thereof is 1 The ratio is set to be greater than 0.7 and less than or equal to 1.5.

[0253] In this embodiment, the minimum distance L between the second groove 223 and the first outer surface 2123a is 4 The minimum distance L from the second groove 223 to the second outer surface 2124a 5 When the difference between the first outer surface 2123a and the second outer surface 2124a is greater than or equal to 0.4 times the distance D between the first outer surface 2123a and the second outer surface 2124a, the distance of the second groove 223 from the center position of the first wall 211 in the first direction Y is large, so that the second groove 223 is closer to the first outer surface 2123a or the second outer surface 2124a, so that the rigidity of the position where the second groove 223 is set on the first wall 211 is greatly different from the rigidity of the position where the first groove 221 is set on the first wall 211, and the rigidity has a greater impact on the first weak portion 224 and the second weak portion 225 of the first wall 211 when cracking. If the impact of the rigidity on the first weak portion 224 and the second weak portion 225 of the first wall 211 is not considered, the cross-sectional area of ​​the second weak portion 225 perpendicular to its extension direction only needs to be greater than the cross-sectional area of ​​the weak section 2241 perpendicular to its extension direction, that is, the cross-sectional area S of the second weak portion 225 perpendicular to its extension direction 2 Greater than the cross-sectional area S of the weak section 2241 perpendicular to its extension direction 1 , so that the first weak portion 224 is cracked and pressure relief is performed before the second weak portion 225, and the second weak portion 225 plays a guiding role in the predetermined pressure relief area 222 defined by the first groove 221. However, considering that the rigidity has a greater influence on the cracking of the first weak portion 224 and the second weak portion 225 (in S 1 and S 2 Under the same circumstances, the second weak portion 225 is more difficult to crack than the first weak portion 224. Therefore, the cross-sectional area of ​​the second weak portion 225 can be set to be smaller), so that when the ratio of the cross-sectional area of ​​the second weak portion 225 perpendicular to its extension direction to the cross-sectional area of ​​the weak section 2241 perpendicular to its extension direction is greater than 0.7 and less than or equal to 1, the first weak portion 224 can open and release pressure before the second weak portion 225, and the second weak portion 225 can guide the predetermined pressure relief area 222 defined by the first groove 221. Similarly, since the stiffness has a greater influence on the cracking of the first weak portion 224 and the second weak portion 225, when the ratio of the cross-sectional area of ​​the second weak portion 225 perpendicular to its extension direction to the cross-sectional area of ​​the weak section 2241 perpendicular to its extension direction is less than or equal to 1.5, the phenomenon of excessive difference in stiffness between the second weak portion 225 and the first weak portion 224 can be alleviated, so that the stiffness of the second weak portion 225 is close to that of the first weak portion 224, and thus the obstacle to the flipping and opening of the predetermined pressure relief area 222 can be reduced, so that the predetermined pressure relief area 222 can be more easily flipped and opened during pressure relief, which is conducive to alleviating the risk of explosion or bursting of the outer shell 21 of the battery cell 20 due to untimely pressure relief of the first wall 211.

[0254] In some embodiments, see Figure 6 As shown, along the first direction Y, the distance between the first outer surface 2123a and the second outer surface 2124a is D, satisfying 15mm≤D≤90mm.

[0255] The distance between the first outer surface 2123 a and the second outer surface 2124 a is D, that is, the thickness of the outer shell 21 of the battery cell 20 in the first direction Y is D.

[0256] Exemplarily, the distance D between the first outer surface 2123a and the second outer surface 2124a can be 15mm, 16mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, 35mm, 39mm, 40mm, 44mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm or 90mm, etc.

[0257] In this embodiment, by setting the distance between the first outer surface 2123a and the second outer surface 2124a in the first direction Y to 15 mm to 90 mm, the size of the shell 21 in the first direction Y is 15 mm to 90 mm. On the one hand, the size of the shell 21 in the first direction Y is set to be greater than or equal to 15 mm, so that the first wall 211 arranged on the first wall 211 has sufficient space in the first direction Y to set the first groove 221 and the second groove 223, which is conducive to reducing the difficulty of setting the first wall 211 on the first wall 211 and setting the first groove 221 and the second groove 223 on the first wall 211. On the other hand, the size of the shell 21 in the first direction Y is set to be less than or equal to 90 mm to alleviate the phenomenon that the size of the battery cell 20 in the first direction Y is too large and causes greater manufacturing difficulty.

[0258] According to some embodiments of the present application, see Figure 6 and Figure 7 As shown, along the thickness direction X of the first wall, the projection of the second groove 223 extends out of the two ends of the first groove 221 at both ends in its extension direction.

[0259] Among them, the projection of the second groove 223 extends out of the two ends of the first groove 221 at both ends in its extension direction, that is, the size of the second groove 223 in its extension direction is larger than the first groove 221, and the two ends of the second groove 223 in its extension direction extend out of the two sides of the first groove 221, that is, in the embodiment where the first groove 221 includes the first groove section 2211 and the two second groove sections 2212, the two ends of the second groove 223 in its extension direction extend out of the two sides of the two second groove sections 2212.

[0260] For example, see Figure 7 As shown, the second groove 223 is a structure extending along the second direction Z. Correspondingly, two ends of the second groove 223 in the second direction Z extend beyond two sides of the first groove 221 in the second direction Z respectively.

[0261] In this embodiment, along the thickness direction X of the first wall, by setting the projection of the second groove 223 in its extension direction to extend out of the two ends of the projection of the first groove 221 respectively, the second groove 223 is a structure in which both ends in its extension direction respectively exceed the two ends of the first groove 221. On the one hand, the size of the second groove 223 in the second direction Z is larger than the first groove 221, so that the predetermined pressure relief area 222 defined by the first groove 221 can be turned around the second groove 223, and the turning effect of the predetermined pressure relief area 222 can be improved, so that the pressure relief area of ​​the battery cell 20 can be increased, so as to improve the pressure relief rate of the battery cell 20 when thermal runaway occurs. On the other hand, the absorption effect of the second groove 223 on the residual material extruded from the first groove 221 of the first wall 211 during the molding process can be improved, and the separation effect of the second groove 223 between the first groove 221 and the edge of the first wall 211 can be improved, so as to improve the blocking effect of the second groove 223 on the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces.

[0262] In some embodiments, see Figure 6 As shown, the length of the second groove 223 is L 6 , meet, 8mm≤L 6 ≤60mm.

[0263] For example, in Figure 6 In the embodiment, the second groove 223 is a straight line structure extending along the second direction Z. Correspondingly, the length L of the second groove 223 is 6 It is the maximum dimension of the second groove 223 in the second direction Z.

[0264] For example, the length L of the second groove 223 is 6 It can be 8mm, 9mm, 10mm, 12mm, 15mm, 18mm, 20mm, 22mm, 23mm, 25mm, 28mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm or 60mm, etc.

[0265] In this embodiment, by setting the length of the second groove 223 to 8 mm to 60 mm, on the one hand, setting the length of the second groove 223 to be greater than or equal to 8 mm can effectively reduce the difficulty of processing the second groove 223, and can alleviate the phenomenon that the size of the first groove 221 is smaller due to the limitation of the second groove 223, which is beneficial to increase the area of ​​the region where the first groove 221 is set on the first wall 211. On the other hand, setting the length of the second groove 223 to be less than or equal to 60 mm can alleviate the phenomenon of waste caused by excessive processing of the second groove 223, and can reduce the space occupied by the second groove 223 on the first wall 211, which is beneficial to improve the overall structural strength of the first wall 211.

[0266] According to some embodiments of the present application, see Figure 8 and Fig. 9 As shown, along the thickness direction X of the first wall, the first groove 221 and the second groove 223 are respectively arranged on both sides of the first wall 211 .

[0267] The first groove 221 and the second groove 223 are respectively disposed on both sides of the first wall 211 , that is, the first groove 221 and the second groove 223 are respectively disposed on surfaces of both sides of the first wall 211 in the thickness direction X of the first wall.

[0268] Optionally, the first groove 221 may be disposed on the side of the first wall 211 facing the interior of the housing 21, and correspondingly, the second groove 223 may be disposed on the side of the first wall 211 facing away from the interior of the housing 21. Of course, the first groove 221 may also be disposed on the side of the first wall 211 facing away from the interior of the housing 21, and correspondingly, the second groove 223 may be disposed on the side of the first wall 211 facing the interior of the housing 21. In other embodiments, the first groove 221 and the second groove 223 may be both located on the same side of the first wall 211 in the thickness direction X of the first wall.

[0269] For example, in Fig. 9 In the embodiment, the groove side surface of the second groove 223 and the groove bottom surface of the second groove 223 are set at an obtuse angle, so as to facilitate the processing to form the second groove 223. Similarly, the groove side surface of the first groove 221 and the groove bottom surface of the first groove 221 are set at an obtuse angle, so as to facilitate the processing to form the first groove 221. Fig. 9 In the embodiment, the first groove 221 is a multi-level groove structure arranged along the thickness direction X of the first wall, that is, the first groove 221 is a stepped groove structure, and the groove side surface and the groove bottom surface of each level of the groove are arranged at an obtuse angle.

[0270] In this embodiment, by respectively arranging the first groove 221 and the second groove 223 on both sides of the first wall 211 in the thickness direction X of the first wall, it is convenient to process the first groove 221 and the second groove 223 on both sides of the first wall 211, which is beneficial to reduce the mutual influence between the first groove 221 and the second groove 223 during the processing.

[0271] In some embodiments, please see Figure 8 and Fig. 9 As shown, along the thickness direction X of the first wall, the first groove 221 is disposed on a side of the first wall 211 away from the interior of the housing 21 , that is, the first groove 221 is disposed on the third outer surface 2111 of the first wall 211 .

[0272] In this embodiment, the first groove 221 is disposed on the side of the first wall 211 away from the interior of the housing 21 , thereby facilitating the formation of the first groove 221 on the first wall 211 , thereby reducing the difficulty of processing the first groove 221 and improving the production efficiency of the battery cell 20 .

[0273] In some embodiments, please see Figure 8 and Fig. 9 As shown, along the thickness direction X of the first wall, the second groove 223 is disposed on a side of the first wall 211 facing the interior of the housing 21 .

[0274] In this embodiment, the second groove 223 is arranged on the side of the first wall 211 facing the interior of the outer shell 21, so that the predetermined pressure relief zone 222 can be flipped toward the outside of the outer shell 21 around the bottom wall of the second groove 223 when it is opened, thereby reducing the interference effect of the groove side surface of the second groove 223 on the predetermined pressure relief zone 222 during the flipping process, which is beneficial to improving the flipping effect of the predetermined pressure relief zone 222.

[0275] According to some embodiments of the present application, see Figure 5 , Figure 6 and Figure 7 As shown, the first groove 221 may include a first groove section 2211 and two second groove sections 2212, the two second groove sections 2212 are arranged opposite to each other along the second direction Z, and the second groove sections 2212 and the second groove 223 are arranged along the first direction Y, the first groove section 2211 connects the two second groove sections 2212, the first groove section 2211 and the two second groove sections 2212 jointly define a predetermined pressure relief area 222, and the second direction Z is perpendicular to the thickness direction X of the first wall and the first direction Y.

[0276] The two second slot sections 2212 are arranged opposite to each other along the second direction Z, that is, the two second slot sections 2212 are arranged at intervals along the second direction Z. Figure 6 and Figure 7In the embodiment, the two second slot sections 2212 both extend along the first direction Y.

[0277] It should be noted that in the embodiment in which the first groove 221 includes a first groove section 2211 and two second groove sections 2212, see Figure 7 As shown, the minimum distance L between the second groove 223 and the first groove 221 in the first direction Y is 1 It is the minimum distance between the second groove 223 and the second groove section 2212 in the first direction Y.

[0278] The first slot segment 2211 connects the two second slot segments 2212, that is, the first slot segment 2211 is located between the two second slot segments 2212 in the second direction Z, and the two ends of the first slot segment 2211 are respectively connected to the two second slot segments 2212. Of course, in other embodiments, the first slot segment 2211 can also extend two second slot segments 2212 at both ends in the second direction Z.

[0279] The first groove section 2211 and the two second groove sections 2212 jointly define a predetermined pressure relief area 222, that is, the first groove section 2211 and the two second groove sections 2212 can enclose at least one predetermined pressure relief area 222 on the first wall 211, and the first groove section 2211 and the two second groove sections 2212 are structures arranged along the edge of the predetermined pressure relief area 222, so that the predetermined pressure relief area 222 can be opened with the first groove section 2211 and the two second groove sections 2212 as boundaries, that is, the predetermined pressure relief area 222 is formed in the area enclosed by the first groove section 2211 and the two second groove sections 2212, so that the part of the first wall 211 located in the predetermined pressure relief area 222 can be opened with the first groove section 2211 and the two second groove sections 2212 as boundaries when the battery cell 20 is depressurized, thereby releasing the internal pressure of the battery cell 20.

[0280] Alternatively, see Figure 6 and Figure 7 As shown, the shape of the first groove 221 formed by the first groove section 2211 and the two second groove sections 2212 can be an "H"-shaped structure to form two predetermined pressure relief areas 222 on the first wall 211, and the two predetermined pressure relief areas 222 are respectively located on both sides of the first groove section 2211 in the first direction Y. Of course, in other embodiments, the first groove 221 can also be other shapes, for example, one end of the two second groove sections 2212 is respectively connected to the two ends of the first groove section 2211, so that the first groove section 2211 and the two second groove sections 2212 enclose a predetermined pressure relief area 222, so that the shape of the first groove 221 formed by the first groove section 2211 and the two second groove sections 2212 is a "U"-shaped structure.

[0281] In this embodiment, the first groove 221 includes two second groove sections 2212 arranged relatively along the second direction Z and a first groove section 2211 connecting the two second groove sections 2212, so that the first wall 211 can be split along the first groove section 2211 and the two second groove sections 2212 when the battery cell 20 is depressurized, so as to open the predetermined pressure relief area 222 to release the internal pressure of the battery cell 20. The first groove 221 with such a structure is convenient for processing the first groove 221 on the first wall 211 and forming the predetermined pressure relief area 222, and the predetermined pressure relief area 222 defined by the first groove 221 with such a structure is easier to flip around the second groove 223. On the other hand, the intersection of the first groove section 2211 and the second groove section 2212 is weaker and easier to split and open the predetermined pressure relief area 222 for pressure relief.

[0282] According to some embodiments of this application, see Figure 6 and Figure 7 As shown, the connection positions of the two second slot sections 2212 and the first slot section 2211 are deviated from the two ends of the two second slot sections 2212, so that predetermined pressure relief areas 222 are formed on both sides of the first slot section 2211 along the first direction Y. The first wall 211 is provided with two second grooves 223, and along the first direction Y, the two second grooves 223 are respectively located on both sides of the first groove 221.

[0283] Among them, the connection positions of the two second groove sections 2212 and the first groove section 2211 are deviated from the two ends of the two second groove sections 2212, that is, the first groove section 2211 is connected between the two ends of the second groove section 2212, so that the shape of the first groove 221 formed by the first groove section 2211 and the two second groove sections 2212 is an approximately "H"-shaped structure, so that the first groove 221 defines two predetermined pressure relief areas 222, and the two predetermined pressure relief areas 222 are respectively located on both sides of the first groove section 2211 in the first direction Y.

[0284] Along the first direction Y, the two second grooves 223 are respectively located on both sides of the first groove 221, that is, the first groove 221 is provided with second grooves 223 on both sides in the first direction Y, and each second groove 223 is provided corresponding to a predetermined pressure relief area 222, so that each second groove 223 can guide the corresponding predetermined pressure relief area 222 to flip.

[0285] In this embodiment, the connection positions of the two second groove sections 2212 and the first groove section 2211 are set to be located between the two ends of the corresponding second groove sections 2212, so that the first groove section 2211 and the two second groove sections 2212 form a first groove 221 similar to an "H"-shaped structure, so that predetermined pressure relief areas 222 can be formed on both sides of the first groove section 2211 of the first groove 221, and the two predetermined pressure relief areas 222 can be opened in a split manner for pressure relief 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.

[0286] In some embodiments, please see Figure 6 and Figure 7 As shown, the first slot section 2211 and the two second slot sections 2212 extend along a straight track, and the first slot section 2211 is perpendicular to the two second slot sections 2212. That is, the extension direction of the first slot section 2211 is perpendicular to the extension direction of the second slot section 2212, so that the shape of the first groove 221 formed by the first slot section 2211 and the two second slot sections 2212 is a regular "H"-shaped structure, and predetermined pressure relief areas 222 are formed on both sides of the first slot section 2211 along the first direction Y. Of course, the areas of the two predetermined pressure relief areas 222 may be the same or different.

[0287] Exemplarily, the first slot segment 2211 is a straight structure extending along the second direction Z, the second slot segment 2212 is a straight structure extending along the first direction Y, and the first slot segment 2211 is located between the two second slot segments 2212 along the second direction Z.

[0288] In this embodiment, by setting the two second groove sections 2212 to be perpendicular to the first groove section 2211, so that the extension direction of the first groove section 2211 is the arrangement direction of the two second groove sections 2212, on the one hand, the regularity of the shape of the first groove 221 can be improved, which is beneficial to reduce the processing difficulty of the first groove 221, so as to reduce the manufacturing cost of the battery cell 20; on the other hand, it is convenient for the two predetermined pressure relief areas 222 on the first wall 211 located on both sides of the first groove section 2211 to relieve pressure in opposite directions when the battery cell 20 is relieved, which is beneficial to improve the pressure relief efficiency of the battery cell 20.

[0289] According to some embodiments of the present application, see Figure 7 As shown, the second slot section 2212 extends along the first direction Y, and the length of the second slot section 2212 in the first direction Y is L 7 , meet, 6mm≤L 7 ≤50mm.

[0290] The length L of the second slot section 2212 in the first direction Y is 7It is the maximum dimension of the second slot segment 2212 in the first direction Y.

[0291] For example, the length L of the second slot segment 2212 in the first direction Y is 7 It can be 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 15mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm or 60mm, etc.

[0292] In this embodiment, by setting the second groove section 2212 as a structure extending along the first direction Y, and the length of the second groove section 2212 in the first direction Y is set to 6 mm to 50 mm, on the one hand, the length of the second groove section 2212 is set to be greater than or equal to 6 mm, so as to increase the area of ​​the predetermined pressure relief area 222 defined by the first groove section 2211 and the two second groove sections 2212, thereby facilitating the increase of the pressure relief area of ​​the battery cell 20, and on the other hand, the length of the second groove section 2212 is set to be less than or equal to 50 mm, so as to save the space occupied by the second groove section 2212 on the first wall 211 along the first direction Y, so that the first groove 221 has sufficient space on one side of the first direction Y to set the second groove 223, so as to reduce the manufacturing difficulty of the second groove 223.

[0293] According to some embodiments of the present application, referring to Fig.10 , Fig.10 The bottom view of the shell 212 of the housing 21 of the battery cell 20 provided in some embodiments of the present application. The first groove 221 includes a first groove section 2211 and a second groove section 2212, which are connected to each other and define a predetermined pressure relief area 222 together.

[0294] Among them, in an embodiment in which a first weak portion 224 is formed at the bottom of the first groove 221 and the first weak portion 224 includes at least one weak section 2241, correspondingly, weak sections 2241 are formed at the bottom of the first groove section 2211 and the bottom of the second groove section 2212, so that the first weak portion 224 formed at the bottom of the first groove 221 includes two weak sections 2241 connected to each other.

[0295] The first groove section 2211 and the second groove section 2212 jointly define a predetermined pressure relief area 222 , that is, the first groove section 2211 and the second groove section 2212 are structures arranged along the edge of the predetermined pressure relief area 222 , so that the setting trajectory of the first groove 221 is arranged along the edge of the predetermined pressure relief area 222 .

[0296] For example, in Fig.10In the embodiment, one end of the first groove section 2211 is connected to one end of the second groove section 2212, so that the first groove section 2211 and the second groove section 2212 form a first groove 221 of a "V"-shaped structure. Correspondingly, the first groove 221 defines only one predetermined pressure relief area 222, and the first wall 211 is only provided with one second groove 223, and the second groove 223 is provided corresponding to the predetermined pressure relief area 222. Of course, in other embodiments, the shape of the first groove 221 formed by the first groove section 2211 and the second groove section 2212 being connected to each other may also be a "T"-shaped structure, an "L"-shaped structure, an "X"-shaped structure, etc.

[0297] In this embodiment, by setting the first groove 221 to have a connected first groove section 2211 and a second groove section 2212, and the first groove section 2211 and the second groove section 2212 jointly define a predetermined pressure relief area 222, on the one hand, the pressure relief area of ​​the battery cell 20 can be increased to increase the pressure relief rate of the battery cell 20, and on the other hand, the intersection of the first groove section 2211 and the second groove section 2212 is made weaker and easier to crack and open the predetermined pressure relief area 222 to release the internal pressure of the battery cell 20.

[0298] According to some embodiments of the present application, referring to Fig.11 , Fig.11 A bottom view of the shell 212 of the housing 21 of the battery cell 20 provided in some embodiments of the present application. The first groove 221 is a groove extending along an arc track, and the predetermined pressure relief area 222 is located inside the first groove 221. In other words, the first groove 221 includes only one smooth groove section, and the first groove 221 is an arc groove structure.

[0299] For example, in Fig.11 In the embodiment, the first groove 221 is in a “C” shape to form a predetermined pressure relief zone 222 inside the arc of the first groove 221 , and the first wall 211 is only provided with one second groove 223 , and the second groove 223 is provided corresponding to the predetermined pressure relief zone 222 .

[0300] In this embodiment, the first groove 221 is set to a structure extending along an arc trajectory so that the predetermined pressure relief area 222 is formed on the inner side of the first groove 221. The first groove 221 with this structure is easy to manufacture on the first wall 211, which is beneficial to reduce the manufacturing difficulty of the battery cell 20.

[0301] According to some embodiments of the present application, see Figure 8 and Fig. 9 As shown, the first groove 221 may include multiple grooves arranged in sequence along the thickness direction X of the first wall. That is, the first groove 221 is a multi-level stepped groove structure arranged along the thickness direction X of the first wall, that is, the first groove 221 is a stepped groove structure formed by multiple stamping.

[0302] For example, in Fig. 9 In the embodiment, the first groove 221 is a two-stage stepped groove structure, that is, the first groove 221 includes two-stage grooves arranged in sequence along the thickness direction X of the first wall. Of course, in other embodiments, the first groove 221 can also be a three-stage stepped groove, a four-stage stepped groove, a five-stage stepped groove or a six-stage stepped groove, etc.

[0303] It should be noted that in the embodiment where the first groove 221 includes a plurality of groove segments, each groove segment is a multi-step groove structure. Figure 7 In the embodiment, the first groove 221 includes a first groove section 2211 and two second groove sections 2212, and the first groove section 2211 and the two second groove sections 2212 are both multi-step groove structures. Of course, when the first groove 221 is a curve, loop or straight line extending along a smooth trajectory, the first groove 221 is a multi-step groove structure.

[0304] In this embodiment, the first groove 221 is set as a multi-step groove structure arranged along the thickness direction X of the first wall, so that the first groove 221 is a groove structure formed by multiple processing. The first groove 221 with this structure can reduce the depth of the first groove 221 processed in a single time under the condition of the same depth, which is beneficial to reduce the manufacturing difficulty of the first groove 221 and the demand for manufacturing equipment, so as to reduce the manufacturing cost, and can reduce the forming force applied to the first wall 211 during the single processing of the first groove 221, which is beneficial to reduce the risk of cracks in the first wall 211, so as to improve the production quality of the battery cell 20. On the other hand, it can improve the flow morphology of the first groove 221 during the formation process, which is beneficial to the flow of the material generated when the first groove 221 is formed, so as to improve the structural consistency of the first groove 221.

[0305] In some embodiments, the first groove 221 is stamped and formed on the first wall 211 ; and / or, the second groove 223 is stamped and formed on the first wall 211 .

[0306] It should be noted that if the first groove 221 is a primary groove structure, when the first groove 221 is formed on the first wall 211, the first wall 211 can be punched once to punch out the first groove 221 on the first wall 211; if the first groove 221 is a multi-stage groove structure, when the first groove 221 is formed on the first wall 211, the first wall 211 can be punched multiple times to punch out a primary groove each time, and the first groove 221 is finally formed after multiple stampings.

[0307] In this embodiment, the first groove 221 is stamped and formed on the first wall 211, so that the molding method of the first groove 221 is simple, which is conducive to reducing the production cost of the battery cell 20. Similarly, the second groove 223 is stamped and formed on the first wall, so that the molding method of the second groove 223 is simple, which is conducive to reducing the production cost of the battery cell 20.

[0308] According to some embodiments of the present application, see Figure 5 and Figure 6 As shown, the first wall 211 is a rectangular structure, and the width direction of the first wall 211 is parallel to the first direction Y.

[0309] Among them, the outer shell 21 of the battery cell 20 is a rectangular structure, and the width direction of the first wall 211 is the first direction Y, and correspondingly, the length direction of the first wall 211 is the second direction Z, so that the second wall 2123 and the third wall 2124 of the shell 212 are the two walls of the shell 212 in the width direction of the first wall 211, so that the thickness direction of the battery cell 20 is the first direction Y.

[0310] In this embodiment, by setting the first wall 211 as a rectangular structure, and the width direction of the first wall is the first direction Y, the second groove 223 is located on one side of the first groove 221 in the width direction of the first wall 211, so that the second groove 223 is provided on the side where extrusion or impact is very likely to occur during the molding process of the first groove 221, so that the second groove 223 can also buffer the extrusion phenomenon of the molding of the first groove 221, and can also play a protective role in buffering the influence of stress on the first groove 221.

[0311] According to some embodiments of the present application, see Figure 8 As shown, along the thickness direction X of the first wall, the minimum residual thickness of the second groove 223 is greater than the minimum residual thickness of the first groove 221. That is, in the thickness direction X of the first wall, the minimum thickness of the bottom wall of the second groove 223 is greater than the minimum thickness of the bottom wall of the first groove 221, that is, in the thickness direction X of the first wall, the groove depth of the first groove 221 is greater than the groove depth of the second groove 223.

[0312] It should be noted that, if in an embodiment in which the first groove 221 includes only one smooth groove segment, the minimum residual thickness of the first groove 221 is the minimum thickness of the residual portion of the first wall 211 at the groove segment; if in an embodiment in which the first groove 221 includes multiple smooth groove segments, the minimum residual thickness of the first groove 221 is the minimum value of the thickness of the residual portion of the first wall 211 at multiple groove segments.

[0313] In this embodiment, by setting the minimum residual thickness of the second groove 223 to be greater than the minimum residual thickness of the first groove 221, the strength of the area of ​​the first wall 211 where the first groove 221 is set is less than the strength of the area of ​​the first wall 211 where the second groove 223 is set, so that the first wall 211 can preferentially crack along the first groove 221 and release the internal pressure of the battery cell 20, which helps to alleviate the phenomenon that the first wall 211 cracks from the area where the second groove 223 is set, causing poor pressure relief effect of the battery cell 20.

[0314] According to some embodiments of the present application, the material of the first wall 211 includes steel.

[0315] Exemplarily, the material of the first wall 211 may be carbon steel, alloy steel, stainless steel or the like.

[0316] It should be noted that the material of the first wall 211 includes steel. If the first wall 211 is the end cover 213 of the outer shell 21, the material of the end cover 213 is steel; if the first wall 211 is a wall in the shell 212, the material of the shell 212 is steel.

[0317] 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.

[0318] In some embodiments, the steel material is carbon steel or stainless steel.

[0319] Illustratively, the carbon steel may be low carbon steel, medium carbon steel or high carbon steel.

[0320] In this embodiment, carbon steel or stainless steel is used as the material of the first wall 211 , which has low cost and is easy to manufacture.

[0321] According to some embodiments of the present application, the material of the first wall 211 includes aluminum alloy.

[0322] It should be noted that the material of the first wall 211 includes aluminum alloy. If the first wall 211 is the end cover 213 of the outer shell 21, the material of the end cover 213 is aluminum alloy; if the first wall 211 is a wall in the shell 212, the material of the shell 212 is aluminum alloy.

[0323] 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 221 and the second groove 223 on the first wall 211, which helps to reduce the manufacturing difficulty of the first groove 221 and the second groove 223.

[0324] In some embodiments, the aluminum alloy includes the following components in mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%.

[0325] In this embodiment, the aluminum alloy belongs to the third series aluminum. The aluminum alloy has lower hardness and better forming ability, which can further reduce the processing difficulty of the first groove 221 and the second groove 223 and improve the processing accuracy of the first groove 221 and the second groove 223, thereby helping to improve the pressure relief consistency of the battery cell 20.

[0326] 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%.

[0327] 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.

[0328] According to some embodiments of the present application, see Figure 3 , Figure 4 and Figure 5 As shown, the housing 21 may include a shell 212 and an end cover 213 . The shell 212 has an accommodating cavity 2121 with an opening 2122 formed inside. The accommodating cavity 2121 is used to accommodate the electrode assembly 23 . The end cover 213 closes the opening 2122 . The shell 212 includes a first wall 211 .

[0329] The shell 212 includes an integrally formed side wall and a bottom wall, that is, the shell 212 is manufactured by an integral molding process, such as an integral molding process such as stamping, casting or extrusion molding, that is, the side wall and the bottom wall of the shell are an integral structure.

[0330] The shell 212 includes a first wall 211, that is, the first wall 211 is a wall of the shell 212. Exemplarily, the first wall 211 is the bottom wall of the shell 212 arranged opposite to the end cover 213 in the thickness direction X of the first wall, that is, the first groove 221 and the second groove 223 are arranged on the bottom wall of the shell 212. Correspondingly, the side wall includes a second wall 2123 and a third wall 2124 arranged opposite to each other along the first direction Y and a fourth wall 2125 and a fifth wall 2126 arranged opposite to each other along the second direction Z. The second wall 2123, the fourth wall 2125, the third wall 2124 and the fifth wall 2126 are connected end to end in sequence to enclose and form the side wall of the shell 212.

[0331] In this embodiment, by setting the first wall 211 of the outer shell 21 as a wall of the shell 212, the battery cell 20 adopting this structure can make the area of ​​the outer shell 21 where the first groove 221 and the second groove 223 are provided away from the end cover 213, thereby effectively alleviating the influence of the stress generated by the connection between the end cover 213 and the shell 212 on the area of ​​the first wall 211 where the first groove 221 and the second groove 223 are provided, which is beneficial to reduce the risk of cracking or structural strength reduction in the area of ​​the first wall 211 where the first groove 221 and the second groove 223 are provided under the pulling action of stress, thereby improving the service life and reliability of the battery cell 20.

[0332] It should be noted that the structure of the battery cell 20 is not limited thereto. In some embodiments, the battery cell 20 may also be other structures. For example, the housing 21 may include a shell 212 and an end cover 213. The interior of the shell 212 forms a receiving cavity 2121 having an opening 2122. The receiving cavity 2121 is used to receive the electrode assembly 23. The end cover 213 closes the opening 2122. The end cover 213 is a first wall 211. In other words, the first groove 221 and the second groove 223 are provided on the end cover 213 of the housing 21. Correspondingly, the second wall 2123 and the third wall 2124 are two walls in the side wall of the housing 212 that are oppositely provided along the first direction Y.

[0333] In this embodiment, by setting the first wall 211 of the outer shell 21 as the end cover 213 of the outer shell 21 for closing the opening 2122, the battery cell 20 adopting this structure is convenient for setting the first groove 221 and the second groove 223 on the end cover 213, which is beneficial to reduce the manufacturing difficulty of the battery cell 20 and improve the production efficiency of the battery cell 20.

[0334] 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 212 and two end covers 213. The shell 212 has a housing chamber 2121 formed inside. The housing chamber 2121 is used to accommodate the electrode assembly 23. Openings 2122 are formed at opposite ends of the shell 212, and the two openings 2122 are connected to the housing chamber 2121. The two end covers 213 respectively close the two openings 2122, and one of the two end covers 213 is a first wall 211.

[0335] In this embodiment, the shell 212 of the outer shell 21 is provided with openings 2122 at both opposite ends, and the two end covers 213 respectively close the two openings 2122, and the first wall 211 is one of the two end covers 213. The battery cell 20 adopting this structure is convenient for assembling the battery cell 20 from both ends of the shell 212, which is beneficial to reducing the manufacturing difficulty and assembly difficulty of the battery cell 20, and is convenient to set the first groove 221 and the second groove 223 on the end cover 213, which is beneficial to reducing the manufacturing difficulty of the battery cell 20 and improving the production efficiency of the battery cell 20.

[0336] Of course, the structure of the battery cell 20 is not limited thereto. In the embodiment where the outer shell 21 includes a shell 212 and two end caps 213, the shell 212 may include a first wall 211, that is, the first wall 211 is a wall in the shell 212. The battery cell 20 with such a structure can make the area where the first wall 211 of the outer shell 21 is provided with the first groove 221 and the second groove 223 away from the end cap 213, thereby effectively alleviating the influence of the stress generated by the connection between the end cap 213 and the shell 212 on the area where the first wall 211 is provided with the first groove 221 and the second groove 223, thereby facilitating reducing the risk of cracking or structural strength reduction in the area where the first wall 211 is provided with the first groove 221 and the second groove 223 under the pulling action of stress, so as to improve the service life and reliability of the battery cell 20.

[0337] According to some embodiments of the present application, the present application further provides a battery 100, and the battery 100 includes a battery cell 20 of any of the above schemes.

[0338] Among them, see Figure 2 As shown, the battery 100 may further include a housing 10 , in which the battery cells 20 are accommodated.

[0339] 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 .

[0340] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure. The first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define an assembly space; the first box body 11 and the second box body 12 can also be hollow structures both with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0341] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder or a cuboid. Figure 2 In the embodiment, the box body 10 is a rectangular parallelepiped structure.

[0342] Optionally, the number of battery cells 20 disposed in the box body 10 may be one or more. Figure 2 In the embodiment, a plurality of battery cells 20 are arranged in the box 10 of the battery 100, and the plurality of battery cells 20 can be connected in series, in parallel or in a mixed connection. The mixed connection means that the plurality of battery cells 20 are both connected in series and in parallel. The plurality of battery cells 20 can be directly connected in series, in parallel or in a mixed connection, and then the whole formed by the plurality of battery cells 20 is accommodated in the box 10; of course, the battery 100 can also be a battery module formed by first connecting the plurality of battery cells 20 in series, in parallel or in a mixed connection, and then the plurality of battery modules are connected in series, in parallel or in a mixed connection to form a whole, and then accommodated in the box 10.

[0343] The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component, which connects the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0344] It should be noted that, in some embodiments, the battery 100 may not be provided with a box 10, and the battery 100 includes a plurality of battery cells 20, and the battery 100 composed of a plurality of battery cells 20 may be directly assembled on an electrical device to provide electrical energy to the electrical device through the plurality of battery cells 20. In other words, the box 10 may be used as a part of the electrical device. Taking the vehicle 1000 as an example of the electrical device, the box 10 may be used as a part of the chassis structure of the vehicle 1000, for example, a part of the box 10 may become at least a part of the floor of the vehicle 1000, or a part of the box 10 may become at least a part of the crossbeam and longitudinal beam of the vehicle 1000.

[0345] According to some embodiments of the present application, the present application further provides an electrical device, which includes a battery cell 20 according to any of the above schemes, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0346] The electrical device may be any of the aforementioned devices or systems using the battery cell 20 .

[0347] According to some embodiments of the present application, see Figures 3 to 9 As shown, the present application provides a battery cell 20, which includes a shell 21 and an electrode assembly 23. The shell 21 is a rectangular parallelepiped structure, and the shell 21 has a first wall 211. The shell 21 includes a shell 212 and an end cover 213. The shell 212 has an accommodating cavity 2121 with an opening 2122 formed inside. The electrode assembly 23 is accommodated in the accommodating cavity 2121, and the end cover 213 closes the opening 2122. The bottom wall of the shell 212 arranged opposite to the end cover 213 in the thickness direction X of the first wall is the first wall 211. The first wall 211 is a rectangular structure, the width direction of the first wall 211 is the first direction Y, and the length direction of the first wall 211 is the second direction Z. The first wall 211 is provided with a first groove 221 and two second grooves 223. Along the thickness direction X of the first wall, the first groove 221 is provided on the side of the first wall 211 away from the inside of the housing 21, and the second groove 223 is provided on the side of the first wall 211 facing the inside of the housing 21, and the minimum residual thickness of the second groove 223 is greater than the minimum residual thickness of the first groove 221. The first wall 211 is configured to be able to be split along at least part of the first groove 221 when the battery cell 20 is depressurized to release the internal pressure of the battery cell 20. The first groove 221 is a multi-stage groove arranged in sequence along the thickness direction X of the first wall. The first groove 221 includes a first groove section 2211 and two second groove sections 2212. The two second groove sections 2212 are arranged opposite to each other along the second direction Z. The second groove sections 2212 and the second grooves 223 are arranged along the first direction Y. The first groove section 2211 extends along the second direction Z. Both ends of the first groove section 2211 are connected to the two second groove sections 2212 respectively. The first groove section 2211 and the two second groove sections 2212 jointly define a predetermined pressure relief area 222. The two second groove sections 2212 and the first groove section 22 The connection positions of the first and second grooves 2211 are deviated from the two ends of the two second groove sections 2212, so that predetermined pressure relief areas 222 are formed on both sides of the first groove section 2211 along the first direction Y. Along the first direction Y, the two second grooves 223 are respectively located on both sides of the first groove 221, and the second grooves 223 and the first grooves 221 are arranged along the first direction Y. The second grooves 223 are configured to guide at least part of the predetermined pressure relief area 222 to flip, so as to open at least part of the predetermined pressure relief area 222 and release the internal pressure of the battery cell 20. The length of the second groove section 2212 in the first direction Y is L 7 , meet, 6mm≤L 7 ≤50mm. Along the first direction Y, the minimum distance between the projection of the first groove 221 in the thickness direction X of the first wall and the projection of the second groove 223 in the thickness direction X of the first wall is L 1 , meet, 0.1mm≤L1 ≤4mm; optionally, 0.2mm≤L 1 ≤2mm. The housing 21 further comprises a second wall 2123 and a third wall 2124 which are arranged opposite to each other along the first direction Y, the first wall 211 connects the second wall 2123 and the third wall 2124, along the first direction Y, the second wall 2123 has a first outer surface 2123a which faces away from the interior of the housing 21, the third wall 2124 has a second outer surface 2124a which faces away from the interior of the housing 21, along the thickness direction X of the first wall, the first wall 211 has a third outer surface 2111 which faces away from the interior of the housing 21, the third outer surface 2111 is connected to the first outer surface 2123a via the first arc surface 214, and the third outer surface 2111 is connected to the second outer surface 2124a via the second arc surface 215. Along the first direction Y, a second groove 223 is provided between the first groove 221 and the first outer surface 2123a and the second outer surface 2124a. One of the two second grooves 223 is located between the first arc surface 214 and the first groove 221, and the other second groove 223 is located between the second arc surface 215 and the first groove 221. Along the first direction Y, the distance between the first outer surface 2123a and the second outer surface 2124a is D, and the minimum distance between the first groove 221 and the first outer surface 2123a is L. 2 , the minimum distance between the first groove 221 and the second outer surface 2124a is L 3 , satisfying, 0≤|L 2 -L 3 | / D≤0.1,2mm≤L 2 ≤12mm, 2mm≤L 3 ≤12mm, 15mm≤D≤90mm. The minimum distances from the second groove 223 to the first outer surface 2123a and the second outer surface 2124a are L 4 and L 5 , satisfying,|L 5 -L 4 | / D≥0.4, a first weak portion 224 is formed at the bottom of the first groove 221, and the first wall 211 is configured to be able to split along at least part of the first weak portion 224 when the battery cell 20 is depressurized. The first weak portion 224 includes at least one weak section 2241, and the cross-sectional area of ​​the weak section 2241 perpendicular to its extension direction is S 1 The bottom of the second groove 223 forms a second weak portion 225, and the cross-sectional area of ​​the second weak portion 225 perpendicular to its extension direction is S 2 , satisfying, 0.7<S 2 / S 1≤1.5. The second groove 223 extends along the second direction Z, and the two ends of the second groove 223 in the second direction Z extend out of the two sides of the first groove 221 in the second direction Z respectively. The length of the second groove 223 is L 6 , meet, 8mm≤L 6 ≤60mm.

[0348] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0349] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: The housing comprises a first wall, the first wall being provided with a first groove, the first groove defining at least one predetermined pressure relief area, the first wall being configured to be split along at least a portion of the first groove when the battery cell is depressurized; Among them, the first wall is also provided with a second groove, the second groove is arranged along the first direction with the first groove, and the second groove is located on one side of the first groove in the first direction, the first direction is perpendicular to the thickness direction of the first wall, and the second groove is configured to guide at least part of the predetermined pressure relief area to flip so as to open at least part of the predetermined pressure relief area.

2. The battery cell according to claim 1, characterized in that: Along the first direction, the first groove and the second groove are arranged at an interval.

3. The battery cell according to claim 2, characterized in that: Along the first direction, a minimum distance between a projection of the first groove in the thickness direction of the first wall and a projection of the second groove in the thickness direction of the first wall is L1, satisfying 0.1 mm ≤ L1 ≤ 4 mm; optionally, 0.2 mm ≤ L1 ≤ 2 mm.

4. The battery cell according to claim 1, characterized in that: The housing further comprises a second wall and a third wall disposed opposite to each other along the first direction, the first wall connecting the second wall and the third wall, the second wall having a first outer surface facing away from the interior of the housing along the first direction, and the third wall having a second outer surface facing away from the interior of the housing; Wherein, along the first direction, the second groove is arranged between the first groove and the first outer surface; and / or The second groove is disposed between the first groove and the second outer surface along the first direction.

5. The battery cell according to claim 4, characterized in that: Along the thickness direction of the first wall, the first wall has a third outer surface facing away from the interior of the shell, and the third outer surface is connected to the first outer surface through a first arc surface; Wherein, along the first direction, the second groove is located between the first arc surface and the first groove.

6. The battery cell according to claim 4, characterized in that: Along the thickness direction of the first wall, the first wall has a third outer surface facing away from the interior of the shell, and the third outer surface is connected to the second outer surface through a second arc surface; Wherein, along the first direction, the second groove is located between the second arc surface and the first groove.

7. The battery cell according to claim 4, characterized in that: Along the first direction, the difference between the minimum distance L2 from the first groove to the first outer surface and the minimum distance L3 from the first groove to the second outer surface is greater than or equal to 0, and the difference between the minimum distance L2 from the first groove to the first outer surface and the minimum distance L3 from the first groove to the second outer surface is less than or equal to 0.1 times the distance D between the first outer surface and the second outer surface.

8. The battery cell according to claim 6, characterized in that: 2mm≤L2≤12mm; and / or 2mm≤L3≤12mm.

9. The battery cell according to claim 4, characterized in that: Along the first direction, a difference between a minimum distance L4 from the second groove to the first outer surface and a minimum distance L5 from the second groove to the second outer surface is greater than or equal to 0.4 times a distance D between the first outer surface and the second outer surface; A first weak portion is formed at the bottom of the first groove, the first wall is configured to be able to split along at least part of the first weak portion when the battery cell is depressurized, the first weak portion includes at least one weak segment, and a second weak portion is formed at the bottom of the second groove, a cross-sectional area S2 of the second weak portion perpendicular to its extension direction is greater than 0.7 times a cross-sectional area S1 of the weak segment perpendicular to its extension direction, and a cross-sectional area S2 of the second weak portion perpendicular to its extension direction is less than or equal to 1.5 times a cross-sectional area S1 of the weak segment perpendicular to its extension direction.

10. The battery cell according to claim 9, characterized in that: 15mm≤D≤90mm.

11. The battery cell according to claim 1, characterized in that: Along the thickness direction of the first wall, two ends of the projection of the second groove in the extension direction thereof respectively extend out of two end portions of the first groove.

12. The battery cell according to claim 11, characterized in that: The length of the second groove is L6, which satisfies 8mm≤L6≤60mm.

13. The battery cell according to claim 1, characterized in that: Along the thickness direction of the first wall, the first groove and the second groove are respectively arranged on two sides of the first wall.

14. The battery cell according to claim 1, characterized in that: Along the thickness direction of the first wall, the first groove is arranged on a side of the first wall facing away from the interior of the housing.

15. The battery cell according to claim 1, characterized in that: Along the thickness direction of the first wall, the second groove is arranged on a side of the first wall facing the interior of the housing.

16. The battery cell according to claim 1, characterized in that: The first groove includes a first groove section and two second groove sections, the two second groove sections are arranged opposite to each other along a second direction, and the second groove section and the second groove are arranged along the first direction, the first groove section connects the two second groove sections, the first groove section and the two second groove sections jointly define the predetermined pressure relief area, and the second direction is perpendicular to the thickness direction of the first wall and the first direction.

17. The battery cell according to claim 16, characterized in that: The connection positions of the two second slot sections and the first slot section are both offset from the two ends of the two second slot sections, so that the predetermined pressure relief areas are formed on both sides of the first slot section along the first direction; The first wall is provided with two second grooves, and along the first direction, the two second grooves are respectively located on both sides of the first groove.

18. The battery cell according to claim 17, characterized in that: The first slot section and the two second slot sections extend along a straight line, and the first slot section is perpendicular to the two second slot sections.

19. The battery cell according to claim 16, characterized in that: The second slot segment extends along the first direction, and a length of the second slot segment in the first direction is L7, satisfying 6mm≤L7≤50mm.

20. The battery cell according to claim 1, characterized in that The first groove includes a first groove section and a second groove section, the first groove section and the second groove section are connected, and the first groove section and the second groove section jointly define the predetermined pressure relief area.

21. The battery cell according to claim 1, characterized in that: The first groove is a groove extending along an arc track, and the predetermined pressure relief area is located inside the first groove.

22. The battery cell according to claim 1, characterized in that: The first groove includes multiple grooves arranged in sequence along the thickness direction of the first wall.

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

24. The battery cell according to claim 1, characterized in that Along the thickness direction of the first wall, the minimum residual thickness of the second groove is greater than the minimum residual thickness of the first groove.

25. The battery cell according to any one of claims 1 to 24, characterized in that: The housing comprises: A housing having an opening formed therein, wherein the housing is used to accommodate the electrode assembly; an end cap for closing the opening; wherein the housing includes the first wall; or The end cover is the first wall.

26. The battery cell according to any one of claims 1 to 24, characterized in that: The housing comprises: A shell having a receiving cavity formed therein, the receiving cavity being used to receive the electrode assembly, openings being formed at opposite ends of the shell, and both openings being in communication with the receiving cavity; Two end covers, respectively closing the two openings; Wherein, one of the two end covers is the first wall; or The housing includes the first wall.

27. A battery, characterized in that: Comprising the battery cell according to any one of claims 1-26.

28. An electrical device, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 26, wherein the battery cell is used to provide electrical energy.

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