Battery monomer, battery and electric device

Abstract

The invention provides a battery monomer, a battery and a power utilization device, and belongs to the technical field of batteries. The battery monomer comprises a shell and a pressure relief component, the housing includes a first wall. The pressure relief component is arranged on the first wall, a first groove is formed in the pressure relief component, at least one preset pressure relief area is defined by the first groove, and the pressure relief component 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 pressure relief component 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

Battery cells, batteries and electrical devices Technical Field

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

[0002] In recent years, new energy vehicles have experienced rapid development. In the electric vehicle sector, power batteries, as the power source of electric vehicles, play an irreplaceable and important role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also growing. As a core component of new energy vehicles, batteries have high requirements in terms of reliability and service life.

[0003] In battery technology, to ensure the safety of battery cells, scored grooves are typically provided on the outer shell of the battery cell to release internal pressure. This allows the outer shell to rupture at the location of the scored grooves in the event of thermal runaway, releasing the internal pressure. However, existing battery cells have a low pressure release rate when thermal runaway occurs, resulting in the risk of fire and explosion caused by untimely pressure release, and thus low reliability of the battery cells.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can effectively improve the reliability of the battery cell.

[0006] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell and a pressure relief component; the shell comprises a first wall; the pressure relief component is arranged on the first wall, the pressure relief component is provided with a first groove, the first groove defines at least one predetermined pressure relief area, and the pressure relief component is configured to be able to split along at least part of the first groove when the battery cell is pressure-relieved; wherein, the pressure relief component 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 area to flip so as to open at least part of the predetermined pressure relief area.

[0007] In the above technical solution, a pressure relief component is provided on the first wall of the shell, and a first groove and a second groove are provided on the pressure relief component, and the first groove defines a predetermined pressure relief area, so that the predetermined pressure relief area can be opened after the pressure relief component is cracked along at least part of the first groove, and can be flipped 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 that is just in contact or spaced apart, so that the second groove is located on one side of the first groove in the first direction, on the one hand, the first groove and the second groove can be reduced. The interference effect between the grooves facilitates the processing of the first groove and the second groove separately, and can alleviate the phenomenon of the first groove tearing the second groove when it is cracked, which is beneficial to improving the effect of the predetermined pressure relief area flipping around the second groove. On the other hand, it can improve the effect of the predetermined pressure relief area flipping around the position of the second groove after being opened, so as to expand the flipping angle of the predetermined pressure relief area, 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, and thus can reduce the risk of fire, explosion or connection failure of the battery cell due to untimely pressure relief, which is beneficial to improving the reliability of the battery cell.

[0008] In some embodiments, along the first direction, the first groove and the second groove are spaced apart.

[0009] In the above technical solution, by setting the first groove and the second groove to be 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 where the first groove of the pressure relief component is set and the area where the second groove of the pressure relief component 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 conducive to improving the effect of the predetermined pressure relief area flipping around the second groove.

[0010] 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 L1, satisfying 0.1mm≤L1≤4mm; optionally, 0.2mm≤L1≤2mm.

[0011] In the above technical solution, by setting the minimum distance of the projections of the first groove and the second groove along the thickness direction of the first wall in the first direction 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 along the thickness direction of the first wall in the first direction 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 pressure relief component, and can further alleviate the phenomenon of the first groove tearing the second groove when cracking. On the other hand, the minimum distance of the projections of the first groove and the second groove along the thickness direction of the first wall in the first direction 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, thereby further improving the pressure relief rate of the battery cell when thermal runaway occurs. Similarly, by setting the minimum distance between the projections of the first and second grooves along the thickness direction of the first wall in the first direction to 0.2 mm to 2 mm, the minimum distance between the first and second grooves in the first direction is 0.2 mm to 2 mm. On the one hand, the minimum distance between the projections of the first and second grooves along the thickness direction of the first wall in the first direction is further set to be greater than or equal to 0.2 mm to further reduce the interference between the first and second grooves, which helps to further reduce the difficulty of machining the first and second grooves on the pressure relief component and can further alleviate the phenomenon of the first groove tearing the second groove when cracking. On the other hand, by setting the minimum distance between the projections of the first and second grooves along the thickness direction of the first wall in the first direction to be less than or equal to 2 mm, the angle at which the predetermined pressure relief zone flips around the second groove and the pressure relief area after the predetermined pressure relief zone is opened are further increased, thereby further improving the pressure relief rate of the battery cell when thermal runaway occurs. This allows the battery cell to avoid the synchronous tearing of the second groove by the first groove while also improving the effect of flipping around the position of the second groove after the predetermined pressure relief zone is opened.

[0012] 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 provided between the first groove and the first outer surface; and / or, along the first direction, the second groove is provided between the first groove and the second outer surface.

[0013] In the above technical solution, when a 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 pressure relief component is provided with the second groove is greater than the stiffness of the position where the pressure relief component is provided with the first groove. Therefore, when the battery cell releases the internal pressure, the deformation of the pressure relief component at the position where the first groove is located is greater than the deformation of the pressure relief component at the position where the second groove is located, which is conducive to the area where the pressure relief component is provided with the first groove to crack and release the internal pressure of the battery cell in priority to the area where the pressure relief component is provided with the second groove. On the one hand, it can alleviate the phenomenon that the pressure relief component 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 pressure relief component is provided with the second groove is greater than the rigidity of the position where the pressure relief component is provided with the first groove. Therefore, when the battery cell releases the internal pressure, the deformation of the pressure relief component at the position where the first groove is located is greater than the deformation of the pressure relief component at the position where the second groove is located, which is conducive to the area where the pressure relief component is provided with the first groove to crack and release the internal pressure of the battery cell in priority to the area where the pressure relief component is provided with the second groove. On the one hand, it can alleviate the phenomenon that the pressure relief component 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.

[0014] 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.

[0015] 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 does not contact the corner of the shell, thereby reducing 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.

[0016] 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.

[0017] 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 does not contact the corner of the shell, thereby reducing 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.

[0018] In some embodiments, 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.

[0019] In the above technical solution, by setting the difference between the minimum distance L2 between the first groove and the first outer surface and the minimum distance L3 between the first groove and the second outer surface to a ratio of 0 to 0.1 to the distance D between the first outer surface and the second outer surface, 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 pressure relief component. On the other hand, it makes it easier for the area of ​​the pressure relief component where the first groove is set to crack for pressure relief, so that under the same blasting pressure, the residual thickness of the area of ​​the pressure relief component where the first groove is set can be increased to improve the fatigue resistance of the pressure relief component, thereby effectively improving the service life and reliability of the battery cell.

[0020] In some embodiments, along the first direction, the minimum distance between the first groove and the first outer surface is L2, and the minimum distance between the first groove and the second outer surface is L3, satisfying 2mm≤L2≤12mm; and / or 2mm≤L3≤12mm.

[0021] 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, so as to alleviate the phenomenon that the distance between the first groove and the first outer surface is too small, which makes it difficult to set the second groove 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 region where the first groove of the pressure relief component is set is limited, which is conducive to increasing the area of ​​the region where the pressure relief component is 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, so as to alleviate the phenomenon that the distance between the first groove and the second outer surface is too small, which makes it difficult to set the second groove 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 pressure relief component where the first groove is set is limited, which is conducive to increasing the area of ​​the pressure relief component used to set the first groove.

[0022] In some embodiments, along the first direction, the difference between the minimum distance L4 from the second groove to the first outer surface and the minimum distance L5 from the second groove to 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, a first weak portion is formed at the bottom of the first groove, and the pressure relief component 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, 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 the cross-sectional area S1 of the weak section 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 the cross-sectional area S1 of the weak section perpendicular to its extension direction.

[0023] In the above technical solution, when the difference between the minimum distance L4 between the second groove and the first outer surface and the minimum distance L5 between the second groove 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 second groove is offset from the center of the first wall in the first direction by a greater distance, placing the second groove closer to the first outer surface or the second outer surface. This results in a significant difference in the stiffness of the pressure relief component at the location where the second groove is provided and the stiffness of the pressure relief component at the location where the first groove is provided. This stiffness has a greater impact on the rupture of the first and second weak portions of the pressure relief component. If the impact of the stiffness on the first and second weak portions of the pressure relief component is not considered, the cross-sectional area of ​​the second weak portion 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 S2 of the second weak portion perpendicular to its extension direction is greater than the cross-sectional area S1 of the weak section perpendicular to its extension direction. This allows the first weak portion to rupture and release pressure before the second weak portion, and the second weak portion guides the predetermined pressure relief area defined by the first groove. However, considering that the stiffness has a greater impact on the cracking of the first weak portion and the second weak portion (when S1 and S2 are the same, the second weak portion is more difficult to crack than the first weak portion, therefore, the cross-sectional area of ​​the second weak portion can be set to be smaller), when the ratio of the cross-sectional area of ​​the second weak portion 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 portion can be opened before the second weak portion to release pressure, and the second weak portion plays a guiding role in the predetermined pressure relief area defined by the first groove. Similarly, since stiffness has a greater impact on the cracking of the first weak portion and the second weak portion, when the ratio of the cross-sectional area of ​​the second weak portion 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 stiffness between the second weak portion and the first weak portion can be alleviated, so that the stiffness of the second weak portion is close to that of the first weak portion, thereby achieving less resistance to the flipping and opening of the predetermined pressure relief area, so that the predetermined pressure relief area is easier to flip and open during pressure relief, which is beneficial to alleviate the phenomenon of explosion or burst of battery cells caused by untimely pressure relief of the pressure relief component.

[0024] 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.

[0025] 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 pressure relief component 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 pressure relief component on the first wall and setting the first groove and the second groove on the pressure relief component. 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.

[0026] In some embodiments, along the thickness direction of the first wall, two ends of the projection of the second groove in its extension direction respectively extend beyond two ends of the first groove.

[0027] 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 the two end parts of the projection of the first groove respectively extending out, the second groove is a structure in which the two ends in its extension direction respectively exceed the two ends 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 area defined by the first groove can be flipped around the second groove, and the flipping effect of the predetermined pressure relief area can be improved, thereby increasing the pressure relief area of ​​the battery cell to increase 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 residual material squeezed out of the first groove of the pressure relief component 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.

[0028] In some embodiments, the length of the second groove is L6, satisfying 8mm≤L6≤60mm.

[0029] 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 difficulty of processing 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 region where the first groove is set in the pressure relief component. 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 pressure relief component, which is beneficial to improve the overall structural strength of the pressure relief component.

[0030] In some embodiments, along the thickness direction of the first wall, the first groove and the second groove are respectively provided on both sides of the pressure relief component.

[0031] In the above technical solution, by respectively arranging the first groove and the second groove on both sides of the pressure relief component 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 pressure relief component, which is beneficial to reduce the mutual influence of the first groove and the second groove during the processing.

[0032] In some embodiments, along the thickness direction of the first wall, the first groove is provided on a side of the pressure relief component facing away from the interior of the housing.

[0033] In the above technical solution, by arranging the first groove on the side of the pressure relief component away from the interior of the shell, it is convenient to form the first groove on the pressure relief component, which is beneficial to reduce the processing difficulty of the first groove and improve the production efficiency of the battery cell.

[0034] In some embodiments, along the thickness direction of the first wall, the second groove is provided on a side of the pressure relief component facing the interior of the housing.

[0035] In the above technical solution, by arranging the second groove on the side of the pressure relief component facing the inside of the shell, the predetermined pressure relief area 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 area during the flipping process, which is beneficial to improving the flipping effect of the predetermined pressure relief area.

[0036] 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 sections 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.

[0037] In the above technical solution, the first groove includes two second groove sections arranged opposite to each other along the second direction and a first groove section connecting the two second groove sections, so that the pressure relief component can split along the first groove section and the two second groove sections when the battery cell releases pressure, 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, on the one hand, facilitates the processing of the first groove on the pressure relief component and forms 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.

[0038] In some embodiments, the connection positions of the two second slot sections and the first slot section deviate 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 pressure relief component 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.

[0039] 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, the first groove section and the two second groove sections form a first groove with an "H"-shaped structure, so that 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 to relieve pressure when the battery cell is depressurized, which is beneficial to further increase the pressure relief effect of the battery cell and can effectively improve the pressure relief rate of the battery cell.

[0040] In some embodiments, the first slot segment and the two second slot segments extend along straight trajectories, and the first slot segment is perpendicular to the two second slot segments.

[0041] 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 reducing the processing difficulty of the first groove, thereby reducing the manufacturing cost of the battery cell; on the other hand, it is convenient for the two predetermined pressure relief areas on both sides of the first groove section on the pressure relief component to relieve pressure in opposite directions when the battery cell is relieved, which is beneficial to improving the pressure relief efficiency of the battery cell.

[0042] In some embodiments, the second slot segment extends along the first direction, and a length of the second slot segment in the first direction is L7, satisfying 6 mm ≤ L7 ≤ 50 mm.

[0043] 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; 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 pressure relief component along the first direction, so that there is sufficient space on one side of the first groove in the first direction to set the second groove, thereby reducing the manufacturing difficulty of the second groove.

[0044] In some embodiments, the first groove includes a first groove segment and a second groove segment, the first groove segment and the second groove segment are connected, and the first groove segment and the second groove segment jointly define the predetermined pressure relief area.

[0045] 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; on the other hand, the intersection of the first groove section and the second groove section is made weaker, which makes it easier to crack and open the predetermined pressure relief area to release the internal pressure of the battery cell.

[0046] 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.

[0047] 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 this structure is easy to manufacture and form on the pressure relief component, which is beneficial to reduce the manufacturing difficulty of the battery cell.

[0048] In some embodiments, the first groove includes multiple levels of grooves sequentially arranged along the thickness direction of the first wall.

[0049] In the above technical solution, the first groove is set 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 reducing 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 exerted on the pressure relief component during a single processing of the first groove, which is beneficial to reduce the risk of cracks in the pressure relief component, so as to improve the production quality of the battery cell. On the other hand, it 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.

[0050] In some embodiments, the pressure relief component is integrally formed with the first wall.

[0051] In the above technical solution, the pressure relief component is integrally formed with the first wall so that the pressure relief component is a structure integrated on the first wall, that is, the pressure relief component is a wall of the outer shell, and correspondingly, the first wall is provided with a first groove and a second groove. The battery cell adopting this structure can improve the structural strength of the pressure relief component provided on the first wall, and can reduce the risk of leakage caused by improper assembly between the pressure relief component and the first wall.

[0052] In some embodiments, the first groove is stamped and formed on the first wall; and / or the second groove is stamped and formed on the first wall.

[0053] In the above technical solution, by stamping the first groove into the first wall, the first groove is formed in a simple manner, which is conducive to reducing the production cost of the battery cell. Similarly, by stamping the second groove into the first wall, the second groove is formed in a simple manner, which is conducive to reducing the production cost of the battery cell.

[0054] In some embodiments, the pressure relief component is provided separately from the first wall.

[0055] In the above technical solution, by arranging the pressure relief component and the first wall as a separate structure, the pressure relief component is a structure installed on the first wall. The battery cell adopting this structure can reduce the difficulty of setting the pressure relief component on the first wall, and the processing steps of the shell and the pressure relief component can be carried out simultaneously, which is conducive to optimizing the production rhythm of the battery cell.

[0056] In some embodiments, the first wall is a rectangular structure, and a width direction of the first wall is parallel to the first direction.

[0057] 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.

[0058] 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.

[0059] 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 where the pressure relief component is set with the first groove is less than the strength of the area where the pressure relief component is set with the second groove, so that the pressure relief component can preferentially crack along the first groove and release the internal pressure of the battery cell, which is conducive to alleviating the phenomenon that the pressure relief component cracks from the area where the second groove is set, causing poor pressure relief effect of the battery cell.

[0060] In some embodiments, the housing includes a shell and an end cover; a housing having an opening is formed inside the shell, and the housing is used to accommodate the electrode assembly; the end cover closes the opening; wherein the shell includes the first wall; or, the end cover is the first wall.

[0061] In the above technical solution, by configuring the first wall of the housing as a wall of the shell, a battery cell adopting this structure can position the area of ​​the housing where the pressure relief component is provided away from the end cap, thereby effectively alleviating the stress generated by the connection between the end cap and the shell acting on the pressure relief component, thereby reducing the impact on the first and second grooves of the pressure relief component, thereby facilitating the reduction of the risk of cracking or structural strength loss of the pressure relief component under the pulling effect of stress, thereby improving the service life and reliability of the battery cell. By configuring the first wall of the housing as an end cap for closing the opening of the housing, a battery cell adopting this structure facilitates the provision of a pressure relief component on the end cap, thereby reducing the manufacturing difficulty of the battery cell and improving the production efficiency of the battery cell.

[0062] 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.

[0063] In the above technical solution, the shell of the housing is provided with openings at both opposite ends, and the two end covers respectively close the two openings. The first wall is one of the two end covers. A battery cell adopting this structure facilitates the assembly of the battery cell from both ends of the housing, which is conducive to reducing the difficulty of manufacturing and assembling the battery cell. It also facilitates the provision of a pressure relief component on the end cover, which is conducive to reducing the difficulty of manufacturing the battery cell and improving the production efficiency of the battery cell. By providing the first wall of the housing as a wall of the housing, a battery cell adopting this structure can make the area of ​​the housing where the pressure relief component is provided away from the end cover, thereby effectively alleviating the stress generated by the connection between the end cover and the housing from acting on the pressure relief component, thereby reducing the impact on the first groove and the second groove of the pressure relief component, and further facilitating the reduction of the risk of cracking or structural strength reduction of the pressure relief component under the pulling effect of stress, thereby improving the service life and reliability of the battery cell.

[0064] In some embodiments, the first wall is made of steel or aluminum alloy.

[0065] In a second aspect, an embodiment of the present application further provides a battery comprising the above-mentioned battery cell.

[0066] 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

[0067] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0068] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0069] FIG2 is an exploded view of the structure of a battery provided in some embodiments of the present application;

[0070] FIG3 is a schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0071] FIG4 is an exploded view of the structure of a battery cell provided in some embodiments of the present application;

[0072] FIG5 is a schematic structural diagram of a shell of a battery cell housing provided in some embodiments of the present application;

[0073] FIG6 is a bottom view of a housing of a battery cell provided in some embodiments of the present application;

[0074] FIG7 is a partial enlarged view of point A of the housing shown in FIG6 ;

[0075] FIG8 is a partial cross-sectional view of a shell of a battery cell provided in some embodiments of the present application;

[0076] FIG9 is a partial enlarged view of point B of the housing shown in FIG8 ;

[0077] FIG10 is a bottom view of a housing of a battery cell provided in some other embodiments of the present application;

[0078] FIG11 is a bottom view of the shell of the battery cell housing provided in some further embodiments of the present application.

[0079] 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; 214-third A circular arc surface; 215-a second circular arc surface; 22-a pressure relief component; 221-a first groove; 2211-a first groove section; 2212-a second groove section; 222-a predetermined pressure relief area; 223-a second groove; 224-a first weak portion; 2241-a weak section; 225-a second weak portion; 23-an electrode assembly; 231-a pole ear; 24-an electrode terminal; 25-a current collecting component; 200-a controller; 300-a motor; X-a thickness direction of the first wall; Y-a first direction; Z-a second direction. DETAILED DESCRIPTION

[0080] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0081] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0082] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0083] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0084] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0085] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0086] The term "plurality" used in this application refers to two or more (including two).

[0087] 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.

[0088] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0089] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0090] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0091] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0092] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0093] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05O2) and at least one of its modified compounds, etc.

[0094] In some embodiments, a positive electrode may utilize a metal foam. The metal foam may include nickel foam, copper foam, aluminum foam, alloy foam, or the like. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not include a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled or / and deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0095] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0096] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. may be used. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, etc. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0097] 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.

[0098] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0099] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0100] 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.

[0101] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0102] In some embodiments, the separator is a separator membrane. There are many types of separator membranes, and any known separator membrane with a porous structure having good chemical stability and mechanical stability can be selected.

[0103] As an example, the separator can be made of at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. In the case of a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0104] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0105] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0106] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0107] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0108] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0109] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0110] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0111] 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.

[0112] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0113] 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.

[0114] In some embodiments, the electrode assembly is a laminate structure.

[0115] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0116] 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.

[0117] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded segments that are stacked.

[0118] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0119] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0120] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0121] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0122] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0123] As an example, the battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include but are not limited to square-shell, blade-shaped, and polygonal batteries, such as hexagonal batteries.

[0124] 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.

[0125] 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.

[0126] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0127] 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.

[0128] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0129] Batteries, with their outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient, are a vital component of today's new energy development. The development of battery technology requires simultaneous consideration of multiple design factors, including performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge rate. Furthermore, battery safety must also be considered.

[0130] 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 rupture when the battery cell experiences thermal runaway to release the internal pressure of the battery cell, thereby 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 provided 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 as to provide a notched groove on the outer shell to form the pressure relief structure on the outer shell. In order to facilitate the pressure relief of the pressure relief structure, the notched groove is usually provided in an "H" or "Y" shape, etc., so that the area of ​​the outer shell surrounded by the notched groove can be flipped and opened after rupturing along the notched groove, thereby increasing the pressure relief area of ​​the battery cell. However, due to the thickness of the shell, even if the area of ​​the 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, which makes the battery cell have the risk of fire, explosion or connection failure due to untimely pressure relief, thereby resulting in low reliability of the battery cell.

[0131] 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 and a pressure relief component. The shell includes a first wall. The pressure relief component is arranged on the first wall, and the pressure relief component is provided with a first groove, the first groove defines at least one predetermined pressure relief area, and the pressure relief component is configured to be able to split along at least part of the first groove when the battery cell is depressurized. The pressure relief component 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 area to flip so as to open at least part of the predetermined pressure relief area.

[0132] In a battery cell of this structure, a pressure relief component is provided on the first wall of the shell. By providing a first groove and a second groove on the pressure relief component, and the first groove defining a predetermined pressure relief area, the predetermined pressure relief area can be opened after the pressure relief component is cracked along at least part of the first groove, and can be flipped around the position where the second groove is located to release the internal pressure of the battery cell. The first groove and the second groove are arranged in a structure arranged along the first direction, so that the second groove and the first groove are in a structure that is just in contact or spaced apart, so that the second groove is located on one side of the first groove in the first direction. On the one hand, the first groove and the second groove can be reduced. The interference effect between the second grooves makes it easier to process the first groove and the second groove separately, and can alleviate the phenomenon of the first groove tearing the second groove when it is cracked, which is beneficial to improving the effect of the predetermined pressure relief area flipping around the second groove. On the other hand, it can improve the effect of the predetermined pressure relief area flipping around the position of the second groove after being opened, so as to expand the flipping angle of the predetermined pressure relief area, 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, and thus can reduce the risk of fire, explosion or connection failure of the battery cell due to untimely pressure relief, which is beneficial to improving the reliability of the battery cell.

[0133] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and batteries disclosed in this application can be used to construct such electrical devices. This helps alleviate the problem of fire and explosion caused by untimely pressure relief in the battery cells, thereby improving the reliability of the battery cells.

[0134] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0135] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device according to an embodiment of the present application.

[0136] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000. The battery 100 can be arranged at the bottom of the vehicle 1000, or at the head of the vehicle 1000, or at the tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can be used as an operating power source or a power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0137] In some embodiments of the present application, the battery 100 can not only serve as the operating power source or usage power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0138] 2 and 3 , FIG2 is an exploded view of a battery 100 according to some embodiments of the present invention, and FIG3 is a schematic diagram of a battery cell 20 according to some embodiments of the present invention. The battery 100 includes a housing 10 and a battery cell 20 , wherein the battery cell 20 is accommodated in the housing 10 .

[0139] The housing 10 is used to provide assembly space for the battery cells 20 and can adopt a variety of structures. In some embodiments, the housing 10 can include a first housing body 11 and a second housing body 12. The first housing body 11 and the second housing body 12 cover each other, and the first housing body 11 and the second housing body 12 jointly define an assembly space for accommodating the battery cells 20. The second housing body 12 can be a hollow structure with one end open, and the first housing body 11 can be a plate-like structure. The first housing body 11 covers the open side of the second housing body 12, so that the first housing body 11 and the second housing body 12 jointly define the assembly space. The first housing body 11 and the second housing body 12 can also be hollow structures with one end open, and the open side of the first housing body 11 covers the open side of the second housing body 12.

[0140] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid or a cube, etc. For example, in FIG2 , the box body 10 is in the shape of a cuboid.

[0141] In the battery 100, there can be one or more battery cells 20 disposed within the housing 10. When there are multiple battery cells 20 disposed within the housing 10, the multiple battery cells 20 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel configurations within the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure formed by the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 100 can be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid configuration to form a battery module, which is then further connected in series, in parallel, or in a hybrid configuration to form a single structure, which is then housed within the housing 10.

[0142] In some embodiments, the battery 100 may further include other structures. For example, the battery 100 may further include a busbar component, which is used to connect the multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20 .

[0143] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be a rectangular parallelepiped, a cylinder, a prism, or other shapes. For example, in FIG3 , the battery cell 20 is a rectangular parallelepiped.

[0144] According to some embodiments of the present application, referring to FIG3 and further to FIG4, FIG5, FIG6, FIG7, and FIG8, FIG4 is an exploded view of the structure of a battery cell 20 provided in some embodiments of the present application, FIG5 is a schematic structural diagram of the housing 212 of the housing 21 of the battery cell 20 provided in some embodiments of the present application, FIG6 is a bottom view of the housing 212 of the housing 21 of the battery cell 20 provided in some embodiments of the present application, FIG7 is a partial enlarged view of the portion A of the housing 212 shown in FIG6, and FIG8 is a partial cross-sectional view of the housing 212 of the housing 21 of the battery cell 20 provided in some embodiments of the present application. The present application provides a battery cell 20, comprising a housing 21 and a pressure relief component 22. The housing 21 includes a first wall 211. The pressure relief component 22 is disposed on the first wall 211 and has a first groove 221 defining at least one predetermined pressure relief area 222. The pressure relief component 22 is configured to rupture along at least a portion of the first groove 221 when the battery cell 20 releases pressure. The pressure relief component 22 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. The second groove 223 is configured to guide at least a portion of the predetermined pressure relief area 222 to flip so as to open at least a portion of the predetermined pressure relief area 222.

[0145] 4 , the battery cell 20 may further include an electrode assembly 23, which is housed in the outer shell 21. The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. 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 isolating member, and a negative electrode sheet, or a stacked structure formed by stacking a positive electrode sheet, an isolating member, and a negative electrode sheet.

[0146] Illustratively, the separator is an isolation membrane, and a main material of the isolation membrane may be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride.

[0147] Optionally, the number of electrode assemblies 23 housed within the housing 21 may be one or more. For example, in FIG4 , two electrode assemblies 23 are disposed within the housing 21 of the battery cell 20, and the two electrode assemblies 23 are stacked along the thickness of the battery cell 20. In other embodiments, the number of electrode assemblies 23 housed within the housing 21 may be one, three, four, five, six, seven, or eight.

[0148] The housing 21 can also be used to contain an electrolyte, such as an electrolyte solution. The housing 21 can have various structural forms, such as a cylinder, a rectangular parallelepiped, or a prismatic structure. Similarly, the housing 21 can be made of various materials, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0149] In some embodiments, the housing 21 may include a shell 212 and an end cover 213, and a accommodating cavity 2121 is formed inside the shell 212, and the accommodating cavity 2121 is used to accommodate the electrode assembly 23, and the accommodating cavity 2121 has an opening 2122, that is, the shell 212 is a hollow structure with an opening 2122 at one end, and the end cover 213 covers the opening 2122 of the shell 212 and forms a sealed connection to form an enclosed space for accommodating the electrode assembly 23 and the electrolyte.

[0150] It should be noted that the first wall 211 on which the pressure relief component 22 is provided may be the end cover 213 of the housing 21, or may be a wall of the shell 212 of the housing 21. For example, in Figures 4, 5 and 6, the first wall 211 is the bottom wall of the shell 212 that is arranged opposite to the end cover 213 in the thickness direction X of the first wall. The shell 212 also includes a second wall 2123, a third wall 2124, a fourth wall 2125 and a fifth wall 2126 that are connected end to end in sequence, and the second wall 2123, the third wall 2124, the fourth wall 2125 and the fifth wall 2126 are all connected to the first wall 211 at one end in the thickness direction X of the first wall, and the second wall 2123, the third wall 2124, the fourth wall 2125 and the fifth wall 2126 are enclosed at the other end in the thickness direction X of the first wall 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 collectively form a housing cavity 2121 for accommodating the electrode assembly 23. The second wall 2123 and the third wall 2124 are arranged relative to each other along a first direction Y, and the fourth wall 2125 and the fifth wall 2126 are arranged relative to each other along a 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, which is also the thickness direction of the battery cell 20. 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 to this. In other embodiments, the first wall 211 may also be an end cap 213, or the first wall 211 may also be a side wall of the housing 212 adjacent to and connected to the end cap 213.

[0151] When assembling the battery cell 20 , the electrode assembly 23 may be placed in the housing 212 and filled with electrolyte. The end cap 213 may then be placed on the opening 2122 of the housing 212 to complete the assembly of the battery cell 20 .

[0152] The shell 212 can be of various shapes, such as a cylinder, a rectangular parallelepiped, or a prismatic 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 has a cylindrical structure, a shell 212 with a cylindrical structure can be selected; if the electrode assembly 23 has a rectangular parallelepiped structure, a shell 212 with a rectangular parallelepiped structure can be selected. Of course, the structure of the end cap 213 can also be various, such as a plate-like structure or a hollow structure with one end open. For example, in Figure 4, the shell 212 has a rectangular parallelepiped structure and the end cap 213 has a rectangular plate-like structure.

[0153] Of course, it is understandable that the shell 21 is not limited to the above structure. The shell 21 may also be other structures. For example, the shell 21 may include a shell 212 and two end covers 213. The shell 212 is a hollow structure with openings 2122 on opposite sides. One end cover 213 corresponds to an opening 2122 of the shell 212 and forms a sealed connection to form an enclosed space for accommodating the electrode assembly 23 and the electrolyte. That is, the shell 212 is formed with openings 2122 on opposite sides, and the two end covers 213 are respectively covered on both sides of the shell 212 to close the corresponding openings 2122.

[0154] In some embodiments, as shown in Figures 3 and 4, the battery cell 20 may further include an electrode terminal 24, which is insulated and mounted on the housing 21 and electrically connected to the electrode assembly 23 to output or input electrical energy of the battery cell 20.

[0155] 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 .

[0156] In Figures 3 and 4 , the battery cell 20 includes two electrode terminals 24, which are spaced apart along the second direction Z. Correspondingly, each electrode assembly 23 has two tabs 231, which are spaced apart along the second direction Z and have opposite polarities. The two electrode terminals 24 are electrically connected to the two tabs 231 of the electrode assembly 23, respectively, to enable input or output of the positive and negative electrodes of the battery cell 20. It should be noted that the tabs 231 of the electrode assembly 23 are formed by stacking and connecting regions of the positive electrode sheet that are not coated with the positive electrode active material layer, or by stacking and connecting regions of the negative electrode sheet that are not coated with the negative electrode active material layer. If the tab 231 is used for the positive electrode of the output electrode assembly 23, the tab 231 is a component formed by stacking and connecting the areas on the positive electrode sheet that are not coated with the positive electrode active material layer; if the tab 231 is used for the negative electrode of the output electrode assembly 23, the tab 231 is a component formed by stacking and connecting the areas on the negative electrode sheet that are not coated with the negative electrode active material layer.

[0157] 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.

[0158] Optionally, the electrode terminals 24 may be mounted on the outer shell 21 in various structures. For example, in Figures 3 and 4, both electrode terminals 24 are mounted on the end cap 213 of the outer shell 21. Of course, the structure of the battery cell 20 is not limited to this. In other embodiments, both electrode terminals 24 may be 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.

[0159] In some embodiments, as shown in Figure 4, 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 assemblies 23 with the same polarity of the electrode lugs 231 to achieve electrical connection between the electrode terminal 24 and the electrode assembly 23, which is conducive to reducing the difficulty of assembly between the electrode lug 231 and the electrode terminal 24.

[0160] Exemplarily, the material of the current collecting member 25 may be various, for example, the material of the current collecting member 25 may be copper, iron, aluminum, steel or aluminum alloy.

[0161] In the embodiment of the present application, the pressure relief component 22 serves to relieve pressure in the battery cell 20 , and is used to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

[0162] Optionally, the pressure relief component 22 may have various structures. For example, referring to Figures 5, 6, and 8, the pressure relief component 22 and the first wall 211 of the housing 21 are integrally formed, that is, the pressure relief component 22 is the first wall 211 of the housing 21, that is, the pressure relief component 22 is integrated on the first wall 211 and forms a wall of the housing 21, which is equivalent to the first groove 221 and the second groove 223 being directly provided on the first wall 211. Of course, in other embodiments, the pressure relief component 22 may also be a structure that is separately provided with the first wall 211 of the housing 21, that is, a pressure relief hole for installing the pressure relief component 22 is provided on the first wall 211 of the housing 21, and the pressure relief component 22 is connected to the first wall 211 and covers the pressure relief hole. The connection between the pressure relief component 22 and the first wall 211 may be in various ways, such as welding or clamping.

[0163] The pressure relief component 22 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 pressure relief component 22 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.

[0164] 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. For example, in Figures 6 and 7, 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 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 pressure relief component 22 can split along the edge of the predetermined pressure relief area 222.

[0165] The pressure relief component 22 is configured to be able to rupture 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 pressure relief component 22 where the first groove 221 is provided can rupture, thereby enabling the predetermined pressure relief area 222 to be opened and release the internal pressure of the battery cell 20.

[0166] For example, as shown in FIG8 , along the thickness direction X of the first wall, the first groove 221 is provided on the side of the pressure relief component 22 facing away from the interior of the housing 21, that is, the first groove 221 is provided on the side of the pressure relief component 22 facing away from the electrode assembly 23. Of course, in other embodiments, the first groove 221 may also be provided on the side of the pressure relief component 22 facing the interior of the housing 21, that is, the first groove 221 is provided on the side of the pressure relief component 22 facing the electrode assembly 23.

[0167] The pressure relief component 22 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 provided 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.

[0168] For example, in Figures 6 and 7, 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.

[0169] 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 pressure relief component 22 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 with the bottom wall of the second groove 223 as the axis, so that after the predetermined pressure relief area 222 is flipped over, the interior of the shell 21 and the exterior of the shell 21 are connected to each other and pressure relief is performed.

[0170] For example, as shown in FIG8 , along the thickness direction X of the first wall, the second groove 223 is provided on the side of the pressure relief component 22 facing the interior of the housing 21, that is, the second groove 223 is provided on the side of the pressure relief component 22 facing the electrode assembly 23. Of course, in other embodiments, the second groove 223 may also be provided on the side of the pressure relief component 22 facing away from the interior of the housing 21, that is, the second groove 223 is provided on the side of the pressure relief component 22 facing away from the electrode assembly 23.

[0171] For example, the first groove 221 can be formed by a processing technique such as stamping or milling. Similarly, the second groove 223 can also be formed by a processing technique such as stamping or milling.

[0172] 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, 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, 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.

[0173] 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 any one of 0.16, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.62, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.82, 0.85, 0.88, 0.9, 0.92, 0.95, 0.98, 0.99, etc., or a range of values ​​between any two of them.

[0174] 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.

[0175] Along the thickness direction X of the first wall, the maximum groove depth of the first groove 221 can be any one of 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, etc., or a range value between any two of them.

[0176] 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.

[0177] In this embodiment, a pressure relief component 22 is provided on the first wall 211 of the shell 21. By providing a first groove 221 and a second groove 223 on the pressure relief component 22, 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 pressure relief component 22 is at least partially cracked along the first groove 221, and can be flipped 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 into 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 pressure relief area 222 can be reduced. The interference between the first groove 221 and the second groove 223 facilitates the processing of 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, thereby facilitating the effect of the predetermined pressure relief area 222 flipping around the second groove 223. On the other hand, it can enhance 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, thereby improving the pressure relief rate of the battery cell 20 when thermal runaway occurs, and thereby reducing 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.

[0178] According to some embodiments of the present application, as shown in FIG6 and FIG7 , the first groove 221 and the second groove 223 are spaced apart along the first direction Y. 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 spaced apart 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 spaced apart. In other words, 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 first groove 221 and the second groove 223.

[0179] For example, in Figure 7, the pressure relief component 22 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 are spaced apart from the first groove 221 in the first direction Y.

[0180] In this embodiment, by setting the first groove 221 and the second groove 223 to be 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 where the first groove 221 of the pressure relief component 22 is set and the area where the second groove 223 of the pressure relief component 22 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 conducive to improving the effect of the predetermined pressure relief area 222 flipping around the second groove 223.

[0181] According to some embodiments of the present application, as shown in FIG7 , along the first direction Y, the minimum distance L1 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 satisfies the condition 0.1 mm ≤ L1 ≤ 4 mm. That is, the minimum distance L1 between the first groove 221 and the second groove 223 in the first direction Y is defined as follows:

[0182] Exemplarily, the minimum distance L1 between the projection of the first groove 221 and the projection of the second groove 223 in the thickness direction X of the first wall 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.

[0183] It should be noted that, in an embodiment where the pressure relief component 22 is provided with two second grooves 223 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 FIG7 , the minimum distance between the two second grooves 223 and the first groove 221 in the first direction Y is L1.

[0184] In this embodiment, 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 0.1 mm to 4 mm, so that 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 processing the first groove 221 and the second groove 223 on the pressure relief component 22 can further alleviate the phenomenon that the first groove 221 tears the second groove 223 when it is cracked. 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 area 222 flips around the second groove 223 and the pressure relief area after the predetermined pressure relief area 222 is opened, thereby further improving the pressure relief rate of the battery cell 20 when thermal runaway occurs.

[0185] In some embodiments, referring to FIG. 7 , along the first direction Y, the minimum distance L1 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 satisfies the condition 0.2 mm ≤ L1 ≤ 2 mm. In other words, the minimum gap between the first groove 221 and the second groove 223 in the first direction Y is between 0.2 mm and 2 mm.

[0186] 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 pressure relief component 22, and can further improve the performance of the pressure relief component 22. On the one hand, the phenomenon of the first groove 221 tearing 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 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, so that the battery cell 20 can improve the effect of flipping around the position where the second groove 223 is located after being opened while taking into account the alleviation of the synchronous tearing of the second groove 223 by the first groove 221.

[0187] According to some embodiments of the present application, as shown in Figures 5, 6, 7, and 8, the housing 21 may further include a second wall 2123 and a third wall 2124 disposed opposite each other along a 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 facing away from the interior of the housing 21, and the third wall 2124 has a second outer surface 2124a facing 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.

[0188] Among them, the shell 21 can also include a second wall 2123 and a third wall 2124 arranged opposite to each other 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. For example, 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 arranged opposite to each other 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.

[0189] 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.

[0190] Along the first direction Y, the second groove 223 is provided 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 arranged in sequence along the first direction Y. For example, in FIG7 , the first outer surface 2123a, the second groove 223, and the first groove 221 are all arranged at intervals along the first direction Y.

[0191] In this 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. This allows the rigidity of the pressure relief component 22 at the location where the second groove 223 is provided to be greater than the rigidity of the pressure relief component 22 at the location where the first groove 221 is provided. Consequently, when the battery cell 20 releases internal pressure, the deformation of the pressure relief component 22 at the location where the first groove 221 is provided is greater than the deformation of the pressure relief component 22 at the location where the second groove 223 is provided. This facilitates the region where the first groove 221 of the pressure relief component 22 is provided to rupture and release the internal pressure of the battery cell 20 before the region where the second groove 223 of the pressure relief component 22 is provided. This can alleviate the problem of poor pressure relief of the battery cell 20 caused by the pressure relief component 22 rupturing at the region where the second groove 223 is provided. Furthermore, it can ensure that the predetermined pressure relief area 222 is stably flipped open under the guidance of the bottom wall of the second groove 223.

[0192] In some embodiments, as shown in Figures 6, 7, and 8, a second groove 223 may also be provided between the first groove 221 and the second outer surface 2124a along the first direction Y. In other words, the second outer surface 2124a, the second groove 223, and the first groove 221 are sequentially arranged along the first direction Y.

[0193] For example, in FIG. 7 , the second outer surface 2124 a , the second groove 223 , and the first groove 221 are all spaced apart along the first direction Y. As shown in FIG.

[0194] For example, in Figures 6 and 7, along the first direction Y, a second groove 223 is 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 pressure relief component 22 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.

[0195] In this 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. This allows the rigidity of the pressure relief component 22 at the location where the second groove 223 is provided to be greater than the rigidity of the pressure relief component 22 at the location where the first groove 221 is provided. Consequently, when the battery cell 20 releases internal pressure, the deformation of the pressure relief component 22 at the location where the first groove 221 is provided is greater than the deformation of the pressure relief component 22 at the location where the second groove 223 is provided. This facilitates the pressure relief component 22 at the location where the first groove 221 is provided to rupture and release the internal pressure of the battery cell 20 before the pressure relief component 22 at the location where the second groove 223 is provided. This can alleviate the problem of the pressure relief component 22 rupturing at the location where the second groove 223 is provided, which may result in poor pressure relief of the battery cell 20. Furthermore, it can ensure that the predetermined pressure relief area 222 is stably flipped open under the guidance of the bottom wall of the second groove 223.

[0196] According to some embodiments of the present application, as shown in FIG8 , along the thickness direction X of the first wall, the first wall 211 has a third outer surface 2111 facing 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. Along the first direction Y, the second groove 223 is located between the first arc surface 214 and the first groove 221.

[0197] 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.

[0198] 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.

[0199] For example, in FIG. 8 , the first arc surface 214 and the second groove 223 are spaced apart along the first direction Y. As shown in FIG.

[0200] 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 shell 21, thereby reducing the influence of the stress at the corner of the shell 21 on the area where the second groove 223 is located, and can reduce the processing difficulty of the second groove 223.

[0201] According to some embodiments of the present application, as shown in FIG8 , along the thickness direction X of the first wall, the first wall 211 has a third outer surface 2111 facing away from the interior of the housing 21. The third outer surface 2111 is connected to the second outer surface 2124a via 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.

[0202] Among them, the third outer surface 2111 is connected to the second outer surface 2124a through a 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.

[0203] 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.

[0204] For example, in FIG. 8 , the second arc surface 215 and the second groove 223 are spaced apart along the first direction Y. As shown in FIG.

[0205] 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 shell 21, thereby reducing the influence of the stress at the corner of the shell 21 on the area where the second groove 223 is located, and can reduce the processing difficulty of the second groove 223.

[0206] According to some embodiments of the present application, referring to FIG6 and FIG7, along the first direction Y, the difference between the minimum distance L2 from the first groove 221 to the first outer surface 2123a and the minimum distance L3 from the first groove 221 to the second outer surface 2124a is greater than or equal to 0, and the difference between the minimum distance L2 from the first groove 221 to the first outer surface 2123a and the minimum distance L3 from the first groove 221 to the second outer surface 2124a is less than or equal to the difference between the first outer surface 2123a and the second outer surface 2124a. 0.1 times the distance D between them, that is, the difference obtained by subtracting the smaller one from the larger one of L2 and L3 is greater than or equal to 0 and less than or equal to 0.1 times D, that is, along the first direction Y, the distance between the first outer surface 2123a and the second outer surface 2124a is D, the minimum distance between the first groove 221 and the first outer surface 2123a is L2, and the minimum distance between the first groove 221 and the second outer surface 2124a is L3, satisfying, 0≤|L2-L3| / D≤0.1.

[0207] 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 can be taken to obtain an average value.

[0208] L2 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 a plane perpendicular to the thickness direction X of the first wall and the first outer surface 2123a is L2. 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 can be measured. Multiple measurements can also be taken and averaged to reduce measurement errors.

[0209] L3 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 a plane perpendicular to the thickness direction X of the first wall and the second outer surface 2124a is L3. 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 can be measured. Multiple measurements can also be taken and averaged to reduce measurement errors.

[0210] |L2-L3| / 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.

[0211] 0≤|L2-L3| / 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 relatively small, that is, the first groove 221 is approximately located at the center of the first wall 211 in the first direction Y.

[0212] The value of |L2-L3| / 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.

[0213] In this embodiment, by setting the ratio of the difference between the minimum distance L2 between the first groove 221 and the first outer surface 2123a and the minimum distance L3 between the first groove 221 and the second outer surface 2124a to the distance D between the first outer surface 2123a and the second outer surface 2124a to be between 0 and 0.1, the first groove 221 is located in the middle region of the first wall 211 in the first direction Y. This helps alleviate the phenomenon of the first groove 221 being excessively deviated from the center position of the first wall 211 in the first direction Y. On the one hand, it is convenient to provide the second groove 223 on one side of the first groove 221 along the first direction Y, which helps to reduce the difficulty of providing the second groove 223 on the pressure relief component 22. On the other hand, it makes it easier for the region of the pressure relief component 22 where the first groove 221 is provided to rupture for pressure relief. Therefore, under the same blasting pressure, the residual thickness of the region of the pressure relief component 22 where the first groove 221 is provided can be increased, thereby improving the fatigue resistance of the pressure relief component 22, thereby effectively improving the service life and reliability of the battery cell 20.

[0214] In some embodiments, along the first direction Y, a minimum distance between the first groove 221 and the first outer surface 2123 a is L2, satisfying 2 mm ≤ L2 ≤ 12 mm.

[0215] Exemplarily, the minimum distance L2 between the first groove 221 and the first outer surface 2123a in the first direction Y 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.

[0216] 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, so as to alleviate the phenomenon that the distance between the first groove 221 and the first outer surface 2123a is too small, which makes it difficult to set the second groove 223 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, so as 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 pressure relief component 22 where the first groove 221 is set is limited, which is conducive to increasing the area of ​​the pressure relief component 22 used to set the first groove 221.

[0217] In some embodiments, along the first direction Y, a minimum distance between the first groove 221 and the second outer surface 2124 a is L3, satisfying 2 mm ≤ L3 ≤ 12 mm.

[0218] Exemplarily, the minimum distance L3 between the first groove 221 and the second outer surface 2124a in the first direction Y 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.

[0219] 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, so as to alleviate the phenomenon that the distance between the first groove 221 and the second outer surface 2124a is too small, which makes it difficult to set the second groove 223 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 pressure relief component 22 where the first groove 221 is set is limited, which is conducive to increasing the area of ​​the pressure relief component 22 used to set the first groove 221.

[0220] According to some embodiments of the present application, referring to Figures 6, 7, and 8, and further referring to Figure 9, which is a partial enlarged view of point B of the housing 212 shown in Figure 8, along the first direction Y, the difference between the minimum distance L4 between the second groove 223 and the first outer surface 2123a and the minimum distance L5 between the second groove 223 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, the difference obtained by subtracting the smaller one from the larger one of L4 and L5 is greater than or equal to 0.4 times D. In other words, 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 L4 and L5, respectively, satisfying |L5-L4| / D≥0.4. A first weak portion 224 is formed at the bottom of the first groove 221. The pressure relief component 22 is configured to be able to split along at least a portion of the first weak portion 224 when the battery cell 20 releases pressure. The first weak portion 224 includes at least one weak section 2241. A second weak portion 225 is formed at the bottom of the second groove 223. The cross-sectional area S2 of the second weak portion 225 perpendicular to its extension direction is greater than 0.7 times the cross-sectional area S1 of the weak section 2241 perpendicular to its extension direction, and the cross-sectional area S2 of the second weak portion 225 perpendicular to its extension direction is less than or equal to 1.5 times the cross-sectional area S1 of the weak section 2241 perpendicular to its extension direction. That is, the cross-sectional area of ​​the weak section 2241 perpendicular to its extension direction is S1, and the cross-sectional area of ​​the second weak portion 225 perpendicular to its extension direction is S2, satisfying the condition that 0.7<S2 / S1≤1.5.

[0221] Here, L4 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 a plane perpendicular to the thickness direction X of the first wall and the first outer surface 2123a is L4. 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 can be measured. Multiple measurements can be taken and the average value can be used to reduce measurement errors.

[0222] L5 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 a plane perpendicular to the thickness direction X of the first wall and the second outer surface 2124a is L5. 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 can be measured. Multiple measurements can be taken and the average value can be used to reduce measurement errors.

[0223] It should be noted that, referring to Figure 8, in an embodiment in which the pressure relief component 22 is provided with two second grooves 223, the minimum distance between any second groove 223 and the first outer surface 2123a in the first direction Y is L4, and the minimum distance between any second groove 223 and the second outer surface 2124a in the first direction Y is L5.

[0224] |L5-L4| / 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.

[0225] |L5-L4| / 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 significantly different. That is, the second groove 223 is offset 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 the value of |L5-L4| / D is less than 1. For example, the value of |L5-L4| / 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, 0.39, 0.91, or 0.95, etc.

[0226] A first weak portion 224 is formed at the bottom of the first groove 221, and the pressure relief component 22 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 pressure relief component 22 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 pressure relief component 22 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.

[0227] 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 pressure relief component 22, 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.

[0228] The cross-sectional area of ​​the weak section 2241 perpendicular to its extension direction is S1. That is, the cross-sectional area of ​​the bottom wall of any groove section of the first groove 221 in its extension direction is S1. In other words, S1 is the product of the width of the groove 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, S1 can be obtained by tomography. It should be noted that the groove bottom surface of the first groove 221 and the groove side surface of the first groove 221 can be a structure in which they are 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 can be a structure in which they are connected through an arc chamfered surface. That is to say, 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 an indirectly connected structure, then S1 is the product of the width of the groove bottom surface of any groove segment of the first groove 221 and the thickness of the pressure relief component 22 in the area corresponding to the groove bottom surface of the first groove 221. That is to say, the groove bottom surface of the first groove 221 does not include the arc chamfered surface formed between the groove bottom surface of the first groove 221 and the groove side surface of the first groove 221.

[0229] The bottom of the second groove 223 forms a second weak portion 225, that is, the pressure relief component 22 is provided with a position of the second groove 223 and the portion corresponding to the bottom surface of the second groove 223 is the second weak portion 225, that is, the bottom wall of the second groove 223 is the second weak portion 225.

[0230] Exemplarily, in FIG. 7 and FIG. 8 , the second groove 223 is a linear structure extending along the second direction Z, and correspondingly, the second weak portion 225 is a linear structure extending along the second direction Z.

[0231] The cross-sectional area of ​​the second weak portion 225 perpendicular to its extension direction is S2, that is, the cross-sectional area of ​​the bottom wall of the second groove 223 in its extension direction is S2. In other words, S2 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, S2 can be obtained by tomography. It should be noted that the groove bottom surface of the second groove 223 and the groove side surface of the second groove 223 can be a directly connected structure or an indirectly connected structure. For example, the groove bottom surface of the second groove 223 and the groove side surface of the second groove 223 can be a structure connected by an arc chamfered surface, that is, 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 an indirectly connected structure, then S2 is the product of the width of the groove bottom surface of the second groove 223 and the thickness of the groove bottom wall of the second groove 223, that is, the groove bottom surface of the second groove 223 does not include the arc chamfered surface formed between the groove bottom surface of the second groove 223 and the groove side surface of the second groove 223.

[0232] By restricting the relationship between S1 and S2 , the risk of the second weak portion 225 cracking before the first weak portion 224 when the battery cell 20 is depressurized can be reduced.

[0233] When |L5-L4| / D≥0.4, the value of S2 / S1 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.

[0234] In order to make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present application clearer, the following will be further described in detail with reference to Comparative Examples 1-4 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 merely illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0235] Comparative Example 1

[0236] 1) Preparation of positive electrode

[0237] The positive electrode active material LiNi 0.7 Co 0.1 Mn 0.1 O2, conductive agent Super P, and binder polyvinylidene fluoride (PVDF) are prepared into positive electrode slurry in N-methylpyrrolidone (NMP), wherein the solid content in the positive electrode slurry is 50wt%, and the solid content of LiNi 0.7 Co 0.1 Mn 0.1 The mass ratio of O2, Super P and PVDF is 8:1:1. The positive electrode slurry is coated on the upper and lower surfaces of the current collector aluminum foil and dried at 85°C and then cold pressed. Then, it is trimmed, cut and striped, and dried under vacuum conditions at 85°C for 4 hours to make the positive electrode sheet.

[0238] 2) Preparation of negative electrode sheet

[0239] Graphite, conductive agent Super P, thickener carboxymethyl cellulose (CMC), and adhesive styrene-butadiene rubber (SBR) were mixed evenly in deionized water to prepare a negative electrode slurry, wherein the solid content in the negative electrode slurry was 30wt%, and the mass ratio of graphite, silicon oxide, Super P, CMC, and adhesive styrene-butadiene rubber (SBR) in the solid components was 88:7:3:2. The negative electrode slurry was coated on the upper and lower surfaces of the current collector copper foil and dried at 85°C. Then, it was cold pressed, trimmed, cut into pieces, and slit, and then dried under vacuum conditions at 120°C for 12 hours to prepare a negative electrode sheet.

[0240] 3) Preparation of electrolyte

[0241] In an argon atmosphere glove box (H2O <0.1ppm, O2 <0.1ppm), the fully dried electrolyte salt LiPF6 was dissolved in a mixed solvent (the mixed solvent included ethylene carbonate (EC) and diethyl carbonate (DEC), and ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a mass ratio of 50:50), and after mixing evenly, a liquid electrolyte with a concentration of 1 mol / L was obtained.

[0242] 4) Isolation parts

[0243] A 16 μm polyethylene film was used as a separator.

[0244] 5) Preparation of battery cell 20

[0245] The positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator placed in the middle of the positive and negative electrode sheets to isolate 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 provided on the first wall 211 of the shell 21 of the battery cell 20 (that is, the pressure relief component 22 and the first wall 211 are an integrally formed structure, and the pressure relief component 22 is the first wall 211 of the shell 21) 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 section 2211 extends along the second direction Z, and the two ends of the first groove section 2211 in the second direction Z are respectively connected to the two second groove sections 2212, the first groove section 2211 is located at the center of the first wall 211 in the first direction Y, the shell 21 of the battery cell 20 is 39 mm thick in the first direction Y, 203 mm long in the second direction Z, and 122.7 mm high in the thickness direction X of the first wall. The capacity of the battery cell 20 is 185 Ah.

[0246] 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 difference between the minimum distance L4 between the second groove 223 and the first outer surface 2123a in the first direction Y and the minimum distance L5 between the second groove 223 and the second outer surface 2124a in the first direction Y is different, and the area S1 of the cross section of the weak section 2241 of the first weak portion 224 perpendicular to its extension direction and the area S2 of the cross section of the second weak portion 225 perpendicular to its extension direction are different. When |L5-L4| / D≥0.4 of the battery cell 20, the detonation situation of the pressure relief component 22 during pressure relief is tested under different ratios of the area S2 of the cross section of the second weak portion 225 perpendicular to its extension direction to the area S1 of the cross section of the weak section 2241 of the first weak portion 224 perpendicular to its extension direction. The specific situations are shown in Tables 1 and 2. Specifically, Table 1 shows the situation of |L5-L4| / D=0.4, and Table 2 shows the situation of |L5-L4| / D=0.56.

[0247] The battery cell 20 needs to be pre-processed before testing:

[0248] (1) Drilling a hole at the injection hole of the battery cell 20;

[0249] (2) Insert the hose into the battery cell 20 10 mm from the injection hole;

[0250] (3) Squeeze AB glue onto cardboard and stir evenly;

[0251] (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.

[0252] During the blasting test, a steel clamp was used to clamp both sides of the battery cell 20's outer shell 21 along a first direction Y, specifically the first outer surface 2123a and the second outer surface 2124a of the outer shell 21. A preload force of 3000N was applied, simulating the restrained state of the battery cell 20 in an actual battery 100. Simultaneously, the pressure relief component 22 was videotaped throughout the test to observe its detonation position and the intended reversal of the pressure relief component. Before the test, a flexible hose connected the detonation pressure testing system to the battery cell 20. During the test, the detonation pressure testing system inflated the battery cell 20 at a rate of 0.3 MPa / s and monitored the intake pressure of the battery cell 20 in real time. Inflation ceased when the intake pressure dropped by more than 0.02 MPa. Generally, the intake pressure curve shows an increasing trend. When the intake pressure reaches the detonation pressure of the battery cell 20, it suddenly drops to zero. The maximum value of the curve at this point represents the detonation pressure of the battery cell 20.

[0253] The experimental results of Comparative Examples 1-4 and Examples 1-10 are shown in Tables 1 and 2 below:

[0254] Table 1

[0255] Table 2

[0256] Please refer to Table 1 and Table 2. In combination with Comparative Examples 1 and 3, it can be seen that |L5-L4| / D≥0.4, but S2 / S1≤0.7. At this time, the cross-sectional area of ​​the second weak portion 225 formed at the bottom of the second groove 223 is smaller than that perpendicular to its extension direction. 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.

[0257] Combining Comparative Examples 3 and 4, we can see that if |L5-L4| / D≥0.4, but S2 / S1>1.5, the second weak portion 225 formed at the bottom of the second groove 223 has a larger cross-sectional area perpendicular to its extension direction, resulting in greater rigidity of the second weak portion 225 formed at the bottom of the second groove 223. This significantly hinders the predetermined pressure relief area 222 from flipping open, making it more difficult for the predetermined pressure relief area 222 to flip around the second weak portion 225 after the first weak portion 224 ruptures. This can easily lead to higher detonation pressure, resulting in delayed pressure relief for the battery cell 20, and thus a high risk of bursting or explosion of the battery cell 20's housing 21. In engineering, it is desirable that the detonation position of the pressure relief component 22 be located at the first weak portion 224, with the second weak portion 225 serving only to guide the predetermined pressure relief area 222 to flip open. 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 when |L5-L4| / D≥0.4, if S2 / S1>1.5, the detonation pressure will be higher than the upper limit of the detonation pressure desired by the project.

[0258] Combining Examples 1-5 and 6-10, it can be seen that when |L5-L4| / D ≥ 0.4 and 0.7 < S2 / S1 ≤ 1.5, the detonation position of the pressure relief component 22 can be located at the first weak portion 224 while the detonation pressure meets engineering expectations. Therefore, when |L5-L4| / D ≥ 0.4, the ratio of the cross-sectional area S2 of the second weak portion 225 perpendicular to its extension direction to the cross-sectional area S1 of the weak section 2241 of the first weak portion 224 perpendicular to its extension direction is set to be greater than 0.7 and less than or equal to 1.5.

[0259] In this embodiment, when the difference between the minimum distance L4 from the second groove 223 to the first outer surface 2123a and the minimum distance L5 from the second groove 223 to 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 second groove 223 deviates from the center position of the first wall 211 in the first direction Y by a large distance, so that the second groove 223 is closer to the first outer surface 2123a or the second outer surface 2124a, so that the stiffness of the position where the second groove 223 of the pressure relief component 22 is set is greatly different from the stiffness of the position where the first groove 221 of the pressure relief component 22 is set, and the stiffness has a greater impact on the first weak portion 224 and the second weak portion 225 of the pressure relief component 22 when they are cracked. If the influence of stiffness on the first weak portion 224 and the second weak portion 225 of the pressure relief component 22 is not considered, the cross-sectional area of ​​the second weak portion 225 perpendicular to its extension direction only needs to be larger than the cross-sectional area of ​​the weak section 2241 perpendicular to its extension direction, that is, the cross-sectional area S2 of the second weak portion 225 perpendicular to its extension direction is larger than the cross-sectional area S1 of the weak section 2241 perpendicular to its extension direction, so that the first weak portion 224 cracks and relieves pressure before the second weak portion 225, and the second weak portion 225 guides the predetermined pressure relief area 222 defined by the first groove 221. However, considering that the stiffness has a greater impact on the cracking of the first weak portion 224 and the second weak portion 225 (when S1 and S2 are the same, 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), 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 be opened to release pressure 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. Similarly, since 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, thereby achieving less resistance to the flipping and opening of the predetermined pressure relief area 222, so that the predetermined pressure relief area 222 is easier to flip and open during pressure relief, which is beneficial 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 pressure relief component 22.

[0260] In some embodiments, as shown in FIG. 6 , along the first direction Y, a distance D between the first outer surface 2123 a and the second outer surface 2124 a satisfies 15 mm ≤ D ≤ 90 mm.

[0261] 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.

[0262] 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.

[0263] 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 pressure relief component 22 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 pressure relief component 22 on the first wall 211 and setting the first groove 221 and the second groove 223 on the pressure relief component 22. 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.

[0264] According to some embodiments of the present application, as shown in FIG. 6 and FIG. 7 , 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.

[0265] 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.

[0266] Exemplarily, as shown in FIG. 7 , the second groove 223 is a structure extending along the second direction Z. Correspondingly, both ends of the second groove 223 in the second direction Z extend beyond both sides of the first groove 221 in the second direction Z.

[0267] In this embodiment, along the thickness direction X of the first wall, the projection of the second groove 223 is arranged to extend beyond the two ends of the projection of the first groove 221 in its extension direction, so that the second groove 223 has a structure in which both ends of its extension direction extend beyond the two ends of the first groove 221. On the one hand, the second groove 223 is larger than the first groove 221 in the second direction Z, so that the predetermined pressure relief area 222 defined by the first groove 221 can be rotated around the second groove 223, and the rotation effect of the predetermined pressure relief area 222 can be improved, thereby increasing the pressure relief area of ​​the battery cell 20 and improving the pressure relief rate of the battery cell 20 when thermal runaway occurs. On the other hand, the second groove 223 can improve the absorption effect of the excess material extruded from the first groove 221 of the pressure relief component 22 during the molding process, and can improve the separation effect of the second groove 223 between the first groove 221 and the edge of the first wall 211, thereby improving the effect of the second groove 223 on blocking the deformation energy of the battery cell 20 when the battery cell 20 is subjected to internal and external impact forces.

[0268] In some embodiments, as shown in FIG. 6 , the length of the second groove 223 is L6, which satisfies 8 mm ≤ L6 ≤ 60 mm.

[0269] Exemplarily, in FIG. 6 , the second groove 223 is a linear structure extending along the second direction Z. Correspondingly, the length L6 of the second groove 223 is the maximum dimension of the second groove 223 in the second direction Z.

[0270] Exemplarily, the length L6 of the second groove 223 may be 8 mm, 9 mm, 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 23 mm, 25 mm, 28 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm or 60 mm, etc.

[0271] 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 in the pressure relief component 22. 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 pressure relief component 22, which is beneficial to improve the overall structural strength of the pressure relief component 22.

[0272] According to some embodiments of the present application, as shown in FIG. 8 and FIG. 9 , along the thickness direction X of the first wall, the first groove 221 and the second groove 223 are respectively provided on both sides of the pressure relief component 22 .

[0273] The first groove 221 and the second groove 223 are respectively provided on both sides of the pressure relief component 22 , that is, the first groove 221 and the second groove 223 are respectively provided on the surfaces of both sides of the pressure relief component 22 in the thickness direction X of the first wall.

[0274] Optionally, the first groove 221 may be provided on the side of the pressure relief component 22 facing the interior of the housing 21, and correspondingly, the second groove 223 may be provided on the side of the pressure relief component 22 facing away from the interior of the housing 21. Of course, the first groove 221 may also be provided on the side of the pressure relief component 22 facing away from the interior of the housing 21, and correspondingly, the second groove 223 may be provided on the side of the pressure relief component 22 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 pressure relief component 22 in the thickness direction X of the first wall.

[0275] For example, in FIG9 , the groove side surface of the second groove 223 and the groove bottom surface of the second groove 223 are arranged at an obtuse angle to facilitate 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 arranged at an obtuse angle to facilitate processing to form the first groove 221. In FIG9 , 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 of each level of the groove is arranged at an obtuse angle to the groove bottom surface.

[0276] In this embodiment, by arranging the first groove 221 and the second groove 223 on both sides of the pressure relief component 22 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 pressure relief component 22, which is beneficial to reduce the mutual influence between the first groove 221 and the second groove 223 during the processing.

[0277] In some embodiments, please continue to refer to FIG. 8 and FIG. 9 , along the thickness direction X of the first wall, the first groove 221 is provided on a side of the pressure relief component 22 facing away from the interior of the housing 21 .

[0278] It should be noted that, in the embodiment where the pressure relief component 22 and the first wall 211 are integrally formed, the pressure relief component 22 is correspondingly the first wall 211 , that is, the first groove 221 is provided on the third outer surface 2111 of the first wall 211 .

[0279] In this embodiment, by arranging the first groove 221 on the side of the pressure relief component 22 away from the interior of the shell 21, it is convenient to process and form the first groove 221 on the pressure relief component 22, which is beneficial to reduce the processing difficulty of the first groove 221 and improve the production efficiency of the battery cell 20.

[0280] In some embodiments, please continue to refer to FIG. 8 and FIG. 9 , along the thickness direction X of the first wall, the second groove 223 is provided on a side of the pressure relief component 22 facing the interior of the housing 21 .

[0281] In this embodiment, the second groove 223 is arranged on the side of the pressure relief component 22 facing the interior of the shell 21, so that the predetermined pressure relief area 222 can be flipped toward the outside of the 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 area 222 during the flipping process, which is conducive to improving the flipping effect of the predetermined pressure relief area 222.

[0282] According to some embodiments of the present application, referring to Figures 5, 6 and 7, 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.

[0283] 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 spaced apart along the second direction Z. For example, in FIG6 and FIG7 , the two second slot sections 2212 both extend along the first direction Y.

[0284] It should be noted that, in the embodiment where the first groove 221 includes a first groove section 2211 and two second groove sections 2212, as shown in Figure 7, the minimum distance L1 between the second groove 223 and the first groove 221 in the first direction Y is the minimum distance between the second groove 223 and the second groove section 2212 in the first direction Y.

[0285] The first slot section 2211 connects the two second slot sections 2212, that is, the first slot section 2211 is located between the two second slot sections 2212 in the second direction Z, and the two ends of the first slot section 2211 are respectively connected to the two second slot sections 2212. Of course, in other embodiments, the first slot section 2211 can also extend two second slot sections 2212 at both ends in the second direction Z.

[0286] The first slot section 2211 and the two second slot sections 2212 jointly define a predetermined pressure relief area 222, that is, the first slot section 2211 and the two second slot sections 2212 can enclose at least one predetermined pressure relief area 222 on the pressure relief component 22, and the first slot section 2211 and the two second slot 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 slot section 2211 and the two second slot sections 2212 as boundaries, that is, the predetermined pressure relief area 222 is formed in the area enclosed by the first slot section 2211 and the two second slot sections 2212, so that the part of the pressure relief component 22 located in the predetermined pressure relief area 222 can be opened with the first slot section 2211 and the two second slot sections 2212 as boundaries when the battery cell 20 is depressurized, thereby releasing the internal pressure of the battery cell 20.

[0287] Alternatively, as shown in Figures 6 and 7, the first groove 221 formed by the first groove section 2211 and the two second groove sections 2212 may be in an "H"-shaped structure to form two predetermined pressure relief areas 222 on the pressure relief component 22, 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 may also have 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 first groove 221 formed by the first groove section 2211 and the two second groove sections 2212 is in a "U"-shaped structure.

[0288] In this embodiment, the first groove 221 includes two second groove sections 2212 arranged opposite to each other along the second direction Z and a first groove section 2211 connecting the two second groove sections 2212, so that the pressure relief component 22 can split along the first groove section 2211 and the two second groove sections 2212 when the battery cell 20 releases pressure, 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, on the one hand, facilitates the processing of the first groove 221 on the pressure relief component 22 and forms 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, making it easier to split and open the predetermined pressure relief area 222 for pressure relief.

[0289] According to some embodiments of the present application, as shown in Figures 6 and 7 , the connection positions of the two second slot sections 2212 and the first slot section 2211 are offset from the 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 pressure relief component 22 is provided with two second grooves 223, which are respectively located on both sides of the first groove 221 along the first direction Y.

[0290] Among them, 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, that is, the first slot section 2211 is connected between the two ends 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 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 slot section 2211 in the first direction Y.

[0291] 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 a second groove 223 on both sides in the first direction Y, and each second groove 223 corresponds to a predetermined pressure relief area 222, so that each second groove 223 can guide the corresponding predetermined pressure relief area 222 to flip.

[0292] In this embodiment, by setting the connection positions of the two second groove sections 2212 and the first groove section 2211 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, 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.

[0293] In some embodiments, referring to Figures 6 and 7 , the first slot segment 2211 and the two second slot segments 2212 extend along straight lines, with the first slot segment 2211 being perpendicular to the two second slot segments 2212. That is, the extension direction of the first slot segment 2211 is perpendicular to the extension direction of the second slot segment 2212, so that the first groove 221 formed by the first slot segment 2211 and the two second slot segments 2212 forms a regular "H"-shaped structure, and predetermined pressure relief areas 222 are formed on both sides of the first slot segment 2211 along the first direction Y. Of course, the areas of the two predetermined pressure relief areas 222 may be the same or different.

[0294] 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.

[0295] 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 reducing the processing difficulty of the first groove 221, thereby reducing the manufacturing cost of the battery cell 20; on the other hand, it is convenient for the two predetermined pressure relief areas 222 on both sides of the first groove section 2211 on the pressure relief component 22 to relieve pressure in opposite directions when the battery cell 20 is relieved, which is beneficial to improving the pressure relief efficiency of the battery cell 20.

[0296] According to some embodiments of the present application, as shown in FIG. 7 , the second slot segment 2212 extends along the first direction Y, and the length of the second slot segment 2212 in the first direction Y is L7, satisfying 6 mm ≤ L7 ≤ 50 mm.

[0297] The length L7 of the second slot segment 2212 in the first direction Y is the maximum dimension of the second slot segment 2212 in the first direction Y.

[0298] Exemplarily, the length L7 of the second slot segment 2212 in the first direction Y can be 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm or 60 mm, etc.

[0299] 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 zone 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; 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 pressure relief component 22 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.

[0300] According to some embodiments of the present application, referring to FIG10 , which is a bottom view of the housing 212 of the outer shell 21 of the battery cell 20 provided in yet other 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 together define a predetermined pressure relief area 222.

[0301] In which, 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.

[0302] The first slot section 2211 and the second slot section 2212 jointly define a predetermined pressure relief area 222 , that is, the first slot section 2211 and the second slot 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 .

[0303] For example, in FIG10 , one end of the first groove segment 2211 is connected to one end of the second groove segment 2212, so that the first groove segment 2211 and the second groove segment 2212 form a first groove 221 with a "V"-shaped structure. Correspondingly, the first groove 221 defines only one predetermined pressure relief area 222, and the pressure relief component 22 is provided with only 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 interconnection of the first groove segment 2211 and the second groove segment 2212 may also be a "T"-shaped structure, an "L"-shaped structure, an "X"-shaped structure, etc.

[0304] In this embodiment, by setting the first groove 221 to have a first groove section 2211 and a second groove section 2212 connected, 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 it is easier to crack and open the predetermined pressure relief area 222 to release the internal pressure of the battery cell 20.

[0305] According to some embodiments of the present application, referring to FIG. 11 , FIG. 11 is a bottom view of the housing 212 of the outer shell 21 of the battery cell 20 provided in still further embodiments of the present application. The first groove 221 is a groove extending along an arcuate trajectory, 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 has an arcuate groove structure.

[0306] Exemplarily, in Figure 11, the shape of the first groove 221 is a "C"-shaped structure to form a predetermined pressure relief area 222 on the inner side of the arc of the first groove 221, and the pressure relief component 22 is only provided with one second groove 223, and the second groove 223 is provided corresponding to the predetermined pressure relief area 222.

[0307] 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 and form on the pressure relief component 22, which is beneficial to reduce the manufacturing difficulty of the battery cell 20.

[0308] According to some embodiments of the present application, as shown in Figures 8 and 9 , the first groove 221 may include a plurality of grooves arranged in sequence along the thickness direction X of the first wall. In other words, the first groove 221 is a multi-step 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 operations.

[0309] For example, in Figure 9, the first groove 221 is a two-level stepped groove structure, that is, the first groove 221 includes two-level 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-level stepped groove, a four-level stepped groove, a five-level stepped groove or a six-level stepped groove, etc.

[0310] It should be noted that in embodiments where the first groove 221 includes multiple groove segments, each groove segment has a multi-step groove structure. For example, in FIG7 , the first groove 221 includes a first groove segment 2211 and two second groove segments 2212. Thus, the first groove segment 2211 and the two second groove segments 2212 each have a multi-step groove structure. Of course, if the first groove 221 as a whole is a structure such as a curve, loop, or straight line extending along a smooth trajectory, then the first groove 221 as a whole has a multi-step groove structure.

[0311] 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, under the condition of the same depth, reduce the depth of the first groove 221 processed in a single time, which is beneficial to reducing 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 pressure relief component 22 during a single processing in the first groove 221, which is beneficial to reducing the risk of cracks in the pressure relief component 22, 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.

[0312] According to some embodiments of the present application, as shown in Figures 5, 6, and 8, the pressure relief component 22 is integrally formed with the first wall 211. In other words, the pressure relief component 22 and the first wall 211 are an integral structure, that is, the pressure relief component 22 is the first wall 211, so that the pressure relief component 22 is part of the housing 21, and the first groove 221 and the second groove 223 of the pressure relief component 22 are directly provided on the first wall 211.

[0313] For example, in FIG5 , the first wall 211 is the bottom wall of the housing 212, which is disposed opposite the end cap 213 in the thickness direction X of the first wall. The pressure relief component 22 is the bottom wall of the housing 212, and the first groove 221 and the second groove 223 are directly disposed on the bottom wall of the housing 212. If the first wall 211 is the end cap 213, the pressure relief component 22 is the end cap 213, so that the pressure relief component 22 can close the opening 2122 of the housing 212, and both electrode terminals 24 are mounted on the pressure relief component 22.

[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 is low in cost and 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 is beneficial to reducing 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 individual elements ≤ 0.03%.

[0325] In this embodiment, this aluminum alloy belongs to the third series aluminum. The use of this aluminum alloy has lower hardness and better forming ability, which can further reduce the processing difficulty of the first groove 221 and the second groove 223, and can 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] In this embodiment, the pressure relief component 22 and the first wall 211 are arranged as an integrally formed structure, so that the pressure relief component 22 is a structure integrated on the first wall 211, that is, the pressure relief component 22 is a wall of the outer shell 21, and correspondingly, the first wall 211 is provided with a first groove 221 and a second groove 223. The battery cell 20 adopting this structure can improve the structural strength of the pressure relief component 22 arranged on the first wall 211, and can reduce the risk of leakage caused by improper assembly between the pressure relief component 22 and the first wall 211.

[0329] In some embodiments, the first groove 221 is stamped and formed in the first wall 211 ; and / or the second groove 223 is stamped and formed in the first wall 211 .

[0330] It should be noted that if the first groove 221 is a primary groove structure, when forming the first groove 221 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 forming the first groove 221 on the first wall 211, the first wall 211 can be punched multiple times, each time punching out a primary groove, and the first groove 221 is finally formed after multiple stampings.

[0331] In this embodiment, by stamping the first groove 221 into the first wall 211, the first groove 221 is formed in a simple manner, which helps reduce the production cost of the battery cell 20. Similarly, by stamping the second groove 223 into the first wall, the second groove 223 is formed in a simple manner, which helps reduce the production cost of the battery cell 20.

[0332] Of course, the structure of the battery cell 20 is not limited to this. In some embodiments, the battery cell 20 may also have other structures, for example, the pressure relief component 22 is provided separately from the first wall 211. In other words, the pressure relief component 22 and the first wall 211 are two separate components, and the pressure relief component 22 is installed on the first wall 211. That is, the first wall 211 is provided with a pressure relief hole for installing the pressure relief component 22. The pressure relief component 22 is connected to the hole wall of the pressure relief hole and covers the pressure relief hole. For example, the pressure relief component 22 can be welded to the first wall 211.

[0333] In this embodiment, the pressure relief component 22 and the first wall 211 are arranged as separate structures, so that the pressure relief component 22 is a structure installed on the first wall 211. The battery cell 20 adopting this structure can reduce the difficulty of setting the pressure relief component 22 on the first wall 211, and the processing steps of the outer shell 21 and the processing steps of the pressure relief component 22 can be carried out simultaneously, which is conducive to optimizing the production rhythm of the battery cell 20.

[0334] According to some embodiments of the present application, as shown in FIG. 5 and FIG. 6 , the first wall 211 is a rectangular structure, and the width direction of the first wall 211 is parallel to the first direction Y.

[0335] In which, 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. 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.

[0336] 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 extremely 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.

[0337] According to some embodiments of the present application, as shown in FIG8 , 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.

[0338] 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 pressure relief component 22 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 pressure relief component 22 at multiple groove segments.

[0339] 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 where the pressure relief component 22 is provided with the first groove 221 is smaller than the strength of the area where the pressure relief component 22 is provided with the second groove 223, so that the pressure relief component 22 can preferentially crack along the first groove 221 and release the internal pressure of the battery cell 20, thereby helping to alleviate the phenomenon that the pressure relief component 22 cracks from the area where the second groove 223 is provided, causing poor pressure relief effect of the battery cell 20.

[0340] According to some embodiments of the present application, as shown in Figures 3, 4 and 5, the outer shell 21 may include a shell 212 and an end cover 213, and the interior of the shell 212 forms a accommodating cavity 2121 with an opening 2122, and the accommodating cavity 2121 is used to accommodate the electrode assembly 23, and the end cover 213 closes the opening 2122, and the shell 212 includes a first wall 211.

[0341] The shell 212 includes an integrally formed side wall and bottom wall, that is, the shell 212 is manufactured using an integral molding process, such as an integral molding process such as stamping, casting or extrusion molding, that is, the side wall and bottom wall of the shell are an integral structure.

[0342] 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 pressure relief component 22 is 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.

[0343] 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 pressure relief component 22 is provided away from the end cover 213, thereby effectively alleviating the stress generated by the connection between the end cover 213 and the shell 212 acting on the pressure relief component 22, thereby reducing the impact on the first groove 221 and the second groove 223 of the pressure relief component 22, and further helping to reduce the risk of cracking or structural strength reduction of the pressure relief component 22 under the pulling action of stress, thereby improving the service life and reliability of the battery cell 20.

[0344] It should be noted that the structure of the battery cell 20 is not limited to this. In some embodiments, the battery cell 20 may also have other structures. For example, the outer shell 21 may include a shell 212 and an end cover 213. The shell 212 has an interior forming a receiving cavity 2121 with an opening 2122. The receiving cavity 2121 is used to accommodate the electrode assembly 23. The end cover 213 closes the opening 2122. The end cover 213 is the first wall 211. In other words, the pressure relief component 22 is provided on the end cover 213 of the outer shell 21. Correspondingly, the second wall 2123 and the third wall 2124 are two walls of the side wall of the shell 212 that are oppositely disposed along the first direction Y.

[0345] In this embodiment, by setting the first wall 211 of the shell 21 as the end cover 213 of the shell 21 for closing the opening 2122, the battery cell 20 adopting this structure is convenient for setting the pressure relief component 22 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.

[0346] 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 interior of the shell 212 is formed with a accommodating cavity 2121, and the accommodating cavity 2121 is used to accommodate the electrode assembly 23. Openings 2122 are formed at both opposite ends of the shell 212, and the two openings 2122 are connected to the accommodating cavity 2121. The two end covers 213 respectively close the two openings 2122, and one of the two end covers 213 is the first wall 211.

[0347] 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. 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 for setting the pressure relief component 22 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.

[0348] Of course, the structure of the battery cell 20 is not limited to this. In the embodiment where the outer shell 21 includes a shell 212 and two end caps 213, the shell 212 may also include a first wall 211, that is, the first wall 211 is a wall of the shell 212. The battery cell 20 adopting this structure can make the area of ​​the outer shell 21 where the pressure relief component 22 is provided away from the end caps 213, thereby effectively alleviating the stress generated by the connection between the end caps 213 and the shell 212 acting on the pressure relief component 22, thereby reducing the impact on the first groove 221 and the second groove 223 of the pressure relief component 22, thereby helping to reduce the risk of cracking or structural strength reduction of the pressure relief component 22 under the pulling effect of stress, thereby improving the service life and reliability of the battery cell 20.

[0349] According to some embodiments of the present application, the present application further provides a battery 100 , which includes the battery cell 20 of any of the above solutions.

[0350] As shown in FIG. 2 , the battery 100 may further include a box body 10 , in which the battery cells 20 are accommodated.

[0351] 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 .

[0352] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure, and the first box body 11 covers the open side of the second box body 12, so that the first box body 11 and the second box body 12 jointly define an assembly space; the first box body 11 and the second box body 12 can also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0353] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder or a rectangular parallelepiped, etc. For example, in FIG2 , the box body 10 is a rectangular parallelepiped structure.

[0354] Optionally, the number of battery cells 20 disposed within the housing 10 may be one or more. For example, in FIG2 , the housing 10 of the battery 100 includes multiple battery cells 20, which may be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a configuration in which multiple battery cells 20 are connected in both series and parallel. Multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure formed by the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery 100 may comprise multiple battery cells 20 that are first connected in series, in parallel, or in a hybrid configuration to form a battery module, which is then further connected in series, in parallel, or in a hybrid configuration to form a single structure, which is then housed within the housing 10.

[0355] The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component that connects the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0356] It should be noted that in some embodiments, the battery 100 may not be provided with a housing 10. The battery 100 includes multiple battery cells 20, and the battery 100 composed of multiple battery cells 20 can be directly assembled on an electrical device to provide electrical energy to the electrical device through the multiple battery cells 20. In other words, the housing 10 can serve as part of the electrical device. Taking the vehicle 1000 as an example, the housing 10 can serve as part of the chassis structure of the vehicle 1000. For example, a portion of the housing 10 can form at least a portion of the floor of the vehicle 1000, or a portion of the housing 10 can form at least a portion of the crossbeam and longitudinal beam of the vehicle 1000.

[0357] According to some embodiments of the present application, the present application further provides an electrical device, which includes the battery cell 20 of any of the above solutions, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0358] The electrical device may be any of the aforementioned devices or systems using the battery cell 20 .

[0359] According to some embodiments of the present application, referring to Figures 3 to 9 , the present application provides a battery cell 20, which includes a housing 21 and an electrode assembly 23. The housing 21 is a rectangular parallelepiped structure having a first wall 211. The housing 21 includes a shell 212 and an end cap 213. The interior of the shell 212 forms a receiving cavity 2121 having an opening 2122. The electrode assembly 23 is received in the receiving cavity 2121. The end cap 213 closes the opening 2122. The bottom wall of the shell 212, which is arranged opposite to the end cap 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 pressure relief component 22 facing away from the interior of the housing 21, while the second grooves 223 are provided on the side of the pressure relief component 22 facing the interior of the housing 21. The minimum residual thickness of the second grooves 223 is greater than that of the first grooves 221. The first wall 211 is configured to rupture along at least a portion of the first grooves 221 when pressure is released from the battery cell 20, thereby relieving the internal pressure of the battery cell 20. The first grooves 221 are multi-stage grooves arranged sequentially 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. The two ends of the first groove section 2211 are respectively connected to 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. The two second groove sections 2212 and the first groove section 22 The connection positions of the first groove section 2211 are offset from both ends of the two second groove sections 2212, thereby forming predetermined pressure relief areas 222 on both sides of the first groove section 2211 along the first direction Y. Along the first direction Y, two second grooves 223 are located on either side of the first groove 221, and the second grooves 223 are arranged with the first groove 221 along the first direction Y. The second grooves 223 are configured to guide at least partial flipping of the predetermined pressure relief areas 222, thereby opening at least part of the predetermined pressure relief areas 222 and relieving the internal pressure of the battery cell 20. The length of the second groove section 2212 in the first direction Y is L7, satisfying 6mm≤L7≤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 L1, satisfying 0.1mm≤L1≤4mm; optionally, 0.2mm≤L1≤2mm.The shell 21 also includes a second wall 2123 and a third wall 2124 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 facing away from the interior of the shell 21, and the third wall 2124 has a second outer surface 2124a facing away from the interior of the shell 21. Along the thickness direction X of the first wall, the first wall 211 has a third outer surface 2111 facing away from the interior of the shell 21. The third outer surface 2111 is connected to the first outer surface 2123a through the first arc surface 214, 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, 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 arcuate surface 214 and the first groove 221, and the other second groove 223 is located between the second arcuate 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, the minimum distance between the first groove 221 and the first outer surface 2123a is L2, and the minimum distance between the first groove 221 and the second outer surface 2124a is L3, satisfying the conditions 0 ≤ |L2 - L3| / D ≤ 0.1, 2 mm ≤ L2 ≤ 12 mm, 2 mm ≤ L3 ≤ 12 mm, and 15 mm ≤ D ≤ 90 mm. The minimum distances between the second groove 223 and the first outer surface 2123a and the second outer surface 2124a are L4 and L5, respectively, satisfying the condition |L5-L4| / D≥0.4. A first weak portion 224 is formed at the bottom of the first groove 221. The pressure relief component 22 is configured to rupture along at least a portion of the first weak portion 224 when pressure is released from the battery cell 20. The first weak portion 224 includes at least one weak section 2241, each having a cross-sectional area S1 perpendicular to its extension direction. A second weak portion 225 is formed at the bottom of the second groove 223. The cross-sectional area S2 perpendicular to its extension direction satisfies the condition 0.7<S2 / S1≤1.5. The second groove 223 extends along the second direction Z, with its ends in the second direction Z extending beyond the sides of the first groove 221 in the second direction Z. The length of the second groove 223 is L6, satisfying the condition 8mm≤L6≤60mm.

[0360] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0361] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, comprising: a housing including a first wall; and a pressure relief component disposed on the first wall, the pressure relief component being provided with a first groove that defines at least one predetermined pressure relief area, and the pressure relief component being configured to be able to crack along at least a part of the first groove when the battery cell relieves pressure; wherein, the pressure relief component is further 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 being perpendicular to the thickness direction of the first wall, and the second groove is configured to guide at least a part of the predetermined pressure relief area to flip so as to open at least a part of the predetermined pressure relief area.

2. The battery cell according to claim 1, wherein, Along the first direction, the first groove and the second groove are spaced apart.

3. The battery cell according to claim 2, wherein, Along the first direction, the minimum distance L1 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 satisfies 0.1 mm ≤ L1 ≤ 4 mm; optionally, 0.2 mm ≤ L1 ≤ 2 mm.

4. The battery cell according to any one of claims 1-3, wherein, The housing further includes a second wall and a third wall that are oppositely arranged along the first direction, the first wall connecting the second wall and the third wall, along the first direction, the second wall has a first outer surface facing away from the interior of the housing, and the third wall has a second outer surface facing away from the interior of the housing; wherein, along the first direction, the second groove is provided between the first groove and the first outer surface; and / or along the first direction, the second groove is provided between the first groove and the second outer surface.

5. The battery cell according to claim 4, wherein, Along the thickness direction of the first wall, the first wall has a third outer surface facing away from the interior of the housing, 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 or 5, wherein, Along the thickness direction of the first wall, the first wall has a third outer surface facing away from the interior of the housing, 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 any one of claims 4-6, wherein, 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, wherein, 2 mm ≤ L2 ≤ 12 mm; and / or 2 mm ≤ L3 ≤ 12 mm.

9. The battery cell according to any one of claims 4-8, wherein, Along the first direction, the difference between the minimum distance L4 from the second groove to the first outer surface and the minimum distance L5 from the second groove to 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; A first weak portion is formed at the bottom of the first groove, and the pressure relief component 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, wherein, 15mm≤D≤90mm.

11. The battery cell according to any one of claims 1-10, wherein, 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, wherein, The length of the second groove is L6, which satisfies 8mm≤L6≤60mm.

13. The battery cell according to any one of claims 1-12, wherein, Along the thickness direction of the first wall, the first groove and the second groove are respectively arranged on two sides of the pressure relief component.

14. The battery cell according to any one of claims 1-13, wherein, Along the thickness direction of the first wall, the first groove is arranged on a side of the pressure relief component facing away from the interior of the housing.

15. The battery cell according to any one of claims 1-14, wherein, Along the thickness direction of the first wall, the second groove is arranged on a side of the pressure relief component facing the interior of the housing.

16. The battery cell according to any one of claims 1-15, wherein, 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, wherein, 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; Wherein, the pressure relief component 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, wherein, 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 any one of claims 16-18, wherein, 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 any one of claims 1-15, wherein, 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 any one of claims 1-15, wherein, 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 any one of claims 1-21, wherein, The first groove includes multiple grooves arranged in sequence along the thickness direction of the first wall.

23. The battery cell according to any one of claims 1-22, wherein, The pressure relief component is integrally formed with the first wall.

24. The battery cell according to claim 23, wherein, The first groove is stamped and formed on the first wall; and / or The second groove is stamped and formed on the first wall.

25. The battery cell according to any one of claims 1-22, wherein, The pressure relief component is disposed separately from the first wall.

26. The battery cell according to any one of claims 1-25, wherein, The first wall is a rectangular structure, and a width direction of the first wall is parallel to the first direction.

27. The battery cell according to any one of claims 1-26, wherein, In the thickness direction of the first wall, the minimum remaining thickness of the second groove is greater than the minimum remaining thickness of the first groove.

28. The battery cell according to any one of claims 1-27, wherein, The housing includes: a housing body, with a receiving cavity having an opening formed therein, the receiving cavity being configured to receive an electrode assembly; an end cap, closing the opening; wherein, the housing body includes the first wall; or the end cap is the first wall.

29. The battery cell according to any one of claims 1-27, wherein, The housing includes: a housing body, with a receiving cavity formed therein, the receiving cavity being configured to receive an electrode assembly, openings being formed at both opposite ends of the housing body, and both of the openings communicating with the receiving cavity; two end caps, respectively closing the two openings; wherein, one of the two end caps is the first wall; or the housing body includes the first wall.

30. The battery cell according to any one of claims 1-29, wherein, The material of the first wall includes steel material or aluminum alloy.

31. A battery, comprising a battery cell according to any one of claims 1 - 30.

32. An electrical device, comprising a battery cell according to any one of claims 1 - 30, the battery cell being configured to provide electrical energy.

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