Battery cell, battery and electrical device

Abstract

The embodiments of the present application belong to the technical field of batteries. Provided are a battery cell, a battery and an electrical device. The battery cell comprises a casing and a pressure relief component; the casing comprises a first wall portion, the pressure relief component being arranged on the first wall portion; the pressure relief component comprises a first recess and second recesses, the first recess and at least one second recess jointly defining at least one predetermined pressure relief region; the pressure relief component is configured to be able to rupture along at least a part of the first recess when the battery cell relieves pressure; the second recess is configured to guide at least a part of the predetermined pressure relief region to turn over, so as to open the at least a part of the predetermined pressure relief region. The volume of the first recess is V, and the sum of the areas of all predetermined pressure relief regions is A, satisfying: 0.05 mm≤V / A≤0.5 mm. Thus, the flatness of the surface of the pressure relief component where the first recess is provided can be improved, and both the requirement for the service life of the battery cell during normal use and the requirement for the reliability of the battery cell during thermal runaway are met.

Description

Battery cells, batteries and electrical equipment 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] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and power tools.

[0003] Typical battery cells are equipped with pressure relief components. In the event of thermal runaway, these components release internal pressure to improve reliability. These components can be provided with pressure relief grooves, which can rupture along these grooves during pressure relief to release internal pressure. However, the presence of these grooves can result in poor surface smoothness on the components, impacting battery cell production quality.

[0004] Summary of the Invention

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

[0006] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell and a pressure relief component, the shell comprising a first wall portion, the pressure relief component being arranged on the first wall portion, the pressure relief component comprising a first groove and a second groove, and along the thickness direction of the first wall portion, the projection of the first groove and the projection of at least one second groove jointly define at least one predetermined pressure relief area, the pressure relief component being configured to be able to split along at least a portion of the first groove when the battery cell is pressure-relieved, and the second groove being configured to guide at least a portion of the predetermined pressure relief area to flip over to open at least a portion of the predetermined pressure relief area; wherein, the volume of the first groove is V, the sum of the areas of all predetermined pressure relief areas is A, satisfying: 0.05mm≤V / A≤0.5mm.

[0007] In the above technical solution, the pressure relief component includes a first groove, which allows the pressure relief component to split along at least a portion of the first groove when the battery cell releases pressure, thereby releasing the internal pressure of the battery cell. The pressure relief component also includes a second groove. The first groove and the second groove together define at least one predetermined pressure relief area. The second groove can guide at least a portion of the predetermined pressure relief area to flip, thereby opening at least a portion of the predetermined pressure relief area for pressure relief. The second groove assists the predetermined pressure relief area, making it easier to flip the predetermined pressure relief area, reducing the difficulty of flipping the predetermined pressure relief area, and increasing the opening speed of the predetermined pressure relief area. V / A≤0.5mm, so that when forming the first groove, the excess material squeezed out from the area where the first groove is set in the pressure relief component can be shared by the larger predetermined pressure relief area, reducing the amount of material stacking per unit area of ​​the predetermined pressure relief area, so that the height of the material stacking protrusion formed on the surface of the predetermined pressure relief area due to the squeezing of the material in the area where the first groove is set in the pressure relief component is not too large, on the one hand, the flatness of the surface of the pressure relief component where the first groove is set is improved, and on the other hand, the risk of releasing large residual stress during normal use of the battery cell due to the excessive height of the material stacking protrusion in the predetermined pressure relief area, resulting in reduced fatigue strength of the pressure relief component, thereby improving the service life of the battery cell; V / A≥0.05mm, so that the height of the material stacking protrusion formed on the surface of the predetermined pressure relief area due to the squeezing of the material in the area where the first groove is set in the pressure relief component is not too small, and the residual stress released by the material stacking protrusion helps the pressure relief component to crack along the first groove more promptly when the battery cell thermal runaway occurs, thereby improving the timeliness of pressure relief of the battery cell, reducing the risk of explosion of the battery cell, and thus improving the reliability of the battery cell. Therefore, 0.05mm≤V / A≤0.5mm can not only improve the flatness of the surface of the pressure relief component where the first groove is set, improve the production quality of the battery cell, but also take into account the service life requirements of the battery cell during normal use and the reliability requirements of the battery cell during thermal runaway.

[0008] In some embodiments, 0.1 mm ≤ V / A ≤ 0.35 mm. V / A ≤ 0.35 mm, on the one hand, further improves the smoothness of the surface of the pressure relief component where the first groove is provided, and on the other hand, further reduces the effect of the protrusion of the material stack in the predetermined pressure relief area on the fatigue strength of the pressure relief component; V / A ≥ 0.1 mm, further improves the timeliness of the pressure relief of the battery cell and further reduces the risk of battery cell explosion.

[0009] In some embodiments, 82 mm 3 ≤V≤450mm 3 . V≤450mm 3 , so that the amount of material extruded during the formation of the first groove is not too large, reducing the forming force on the pressure relief component during the formation of the first groove, and reducing the risk of damage to the pressure relief component during the formation of the first groove; V ≥ 82mm 3, so that the amount of extrusion when forming the first groove will not be too small, it is easier to meet the depth, width and length requirements of the first groove, and reduce the difficulty of forming the first groove.

[0010] In some embodiments, 115 mm 3 ≤V≤265mm 3 . V≤265mm 3 , further reducing the amount of material extruded during the formation of the first groove, further reducing the forming force on the pressure relief component during the formation of the first groove, and reducing the risk of damage to the pressure relief component during the formation of the first groove; V ≥ 115mm 3 , further increasing the amount of material extruded when forming the first groove, and further reducing the difficulty of forming the first groove.

[0011] In some embodiments, 160 mm 2 ≤A≤1500mm 2 A≤1500mm 2 , so that the area of ​​the predetermined pressure relief zone is not too large, reducing the risk of the predetermined pressure relief zone being deformed by the pressure change inside the battery cell, causing the pressure relief component to crack prematurely along the first groove; A ≥ 160mm 2 , so that the pressure relief component has a sufficiently large pressure relief area, thereby increasing the pressure relief rate of the battery cell.

[0012] In some embodiments, 400 mm 2 ≤A≤1200mm 2 A≤1200mm 2 , further reducing the risk of premature cracking of the pressure relief component along the first groove. A≥400mm 2 , further improving the pressure release rate of the battery cell.

[0013] In some embodiments, along the thickness direction of the first wall portion, the pressure relief component has a first surface and a second surface relative to each other, and the second groove is recessed from the second surface toward the first surface; along the width direction of the second groove, the second groove includes a first groove side surface and a second groove side surface that are oppositely arranged and connected to the second surface, the first groove side surface is closer to the predetermined pressure relief area than the second groove side surface, the first groove side surface forms an angle a with the second surface, and the second groove side surface forms an angle b with the second surface, satisfying: 90°≤a<b<180°, and the width direction of the second groove is perpendicular to the thickness direction of the first wall portion. In this way, the angle between the first groove side surface and the second surface is reduced, the amount of excess material extruded during the formation of the second groove in the predetermined pressure relief area can be reduced, the height of the material protrusion formed on the surface of the predetermined pressure relief area due to the extrusion of material in the area where the second groove is provided by the pressure relief component is reduced, and the flatness of the surface of the predetermined pressure relief area is improved.

[0014] In some embodiments, 90°≤a≤150° further reduces the angle between the first groove side and the second surface, and further reduces the inclination angle of the first groove side, which is beneficial to reducing the amount of excess material extruded in the predetermined pressure relief area when forming the second groove.

[0015] In some embodiments, 90°<b≤170°, which further reduces the angle between the side surface of the second groove and the second surface, further reduces the inclination angle of the side surface of the second groove, and reduces the difficulty of forming the second groove.

[0016] In some embodiments, the pressure relief component is provided with multiple second grooves. Along the thickness direction of the first wall portion, the projection of the first groove and the projection of the multiple second grooves together define multiple predetermined pressure relief areas, each of which corresponds to one or more second grooves. In the event of thermal runaway of a battery cell, all of the multiple predetermined pressure relief areas can be opened. Given a constant total pressure relief area of ​​the pressure relief component, this can increase the opening rate of the predetermined pressure relief areas, achieving more rapid pressure relief.

[0017] In some embodiments, along the thickness direction of the first wall portion, the projection of the second groove does not overlap with the projection of the first groove, thereby reducing the mutual influence between the first groove and the second groove during the processing and lowering the risk of the first groove and the second groove communicating with each other during the processing.

[0018] In some embodiments, the second groove is spaced apart from the first groove along the width direction of the second groove, and the width direction of the second groove is perpendicular to the thickness direction of the first wall portion. In this way, the projection of the second groove along the thickness direction of the first wall portion and the projection of the first groove along the thickness direction of the first wall portion do not overlap. This can further reduce the mutual influence between the first and second grooves during processing. It can also reduce the influence of residual stress between the pressure relief component in the area where the first groove is provided and the area where the second groove is provided, and can also reduce the risk of cracks caused by cracks in the pressure relief component along the first groove propagating to the second groove, thereby causing the pressure relief component to crack along the second groove.

[0019] In some embodiments, along the thickness direction of the first wall portion, the projection of the second groove extends beyond the projection of the first groove at both ends along the extension direction, thereby making the second groove longer and enhancing the auxiliary flipping effect of the second groove on the predetermined pressure relief area.

[0020] In some embodiments, the minimum residual thickness of the first groove is D1, and the minimum residual thickness of the second groove is D2, satisfying the following: D1 < D2. This ensures that the strength of the region where the first groove is located in the pressure relief component is less than the strength of the region where the second groove is located in the pressure relief component, so that the pressure relief component preferentially ruptures along the first groove, thereby achieving rapid opening of the predetermined pressure relief area.

[0021] In some embodiments, along the thickness direction of the first wall portion, the maximum groove depth of the first groove is H1, and the maximum groove depth of the second groove is H2, satisfying the following: H2 < H1. During production, the depth of the first groove can be machined deeper than the depth of the second groove, so that the minimum residual thickness of the first groove is less than the minimum residual thickness of the second groove.

[0022] In some embodiments, along the thickness direction of the first wall portion, the maximum depth of the first groove is H1, the thickness of the pressure relief component is D, and 0.16 ≤ H1 / D < 1. This ensures that the maximum depth of the first groove accounts for a moderate proportion of the thickness of the pressure relief component, thereby preventing the bursting pressure of the battery cell from being too high, thereby facilitating timely pressure relief of the battery cell.

[0023] In some embodiments, 0.4 mm ≤ H1 ≤ 2 mm, and 0.8 mm ≤ D ≤ 2.5 mm. Controlling the maximum depth of the first groove and the thickness of the pressure relief component within a reasonable range has better economic efficiency.

[0024] In some embodiments, the pressure relief component has a first surface and a second surface facing each other along the thickness direction of the first wall portion, with the first groove being disposed on the first surface and the second groove being disposed on the second surface. The first groove and the second groove are located on opposite sides of the pressure relief component along the thickness direction of the first wall portion, respectively, so that the first groove and the second groove can be machined on both sides of the pressure relief component, thereby minimizing mutual influence between the first groove and the second groove during machining.

[0025] In some embodiments, along the width direction of the second groove, the projection of the first groove and the projection of the second groove at least partially overlap, and the width direction of the second groove is perpendicular to the thickness direction of the first wall portion. This allows the projections of the first groove and the second groove in the width direction of the second groove to have an overlapping area, thereby, on the one hand, improving the second groove's ability to absorb excess material extruded from the first groove during molding, thereby reducing the risk of the extruded excess material from the first groove diffusing to the surface of the housing along the width direction of the second groove, thereby causing unevenness on the surface. On the other hand, it improves the second groove's ability to absorb deformation energy of the battery cell when the battery cell is subjected to internal and external forces and deformed along the width direction of the second groove, thereby reducing the impact of the expansion and deformation of the battery cell along the width direction of the second groove on the pressure relief component.

[0026] In some embodiments, along the thickness direction of the first wall portion, the bottom surface of the second groove is closer to the first surface than the bottom surface of the first groove. This structure facilitates achieving a greater overlap between the projections of the second groove and the first groove in the width direction of the second groove, further improving the second groove's ability to absorb excess material extruded from the first groove during molding, and further improving the second groove's ability to absorb deformation energy from the battery cell when the battery cell is deformed by internal and external forces along the width direction of the second groove.

[0027] In some embodiments, along the thickness direction of the first wall portion, the maximum groove depth of the second groove is H2, and the minimum residual thickness of the first groove is D1, satisfying the following relationship: D1 < H2. This structure facilitates achieving a greater overlap between the projections of the second groove and the first groove in the width direction of the second groove, further enhancing the second groove's ability to absorb excess material extruded from the first groove during molding. It also further enhances the second groove's ability to absorb deformation energy from the battery cell when the cell is deformed by internal and external forces along the width direction of the second groove.

[0028] In some embodiments, the first groove includes a plurality of grooves arranged in sequence along a direction pointing from the first surface to the second surface, and along the thickness direction of the first wall portion, in two adjacent grooves, the first groove farther from the first surface is arranged at the bottom surface of the first groove closer to the first surface; wherein, among the multi-stage grooves, the first groove arranged on the first surface is the first-stage groove, and along the width direction of the second groove, the projection of the second groove at least partially overlaps with the projection of the first-stage groove, and the width direction of the second groove is perpendicular to the thickness direction of the first wall portion. By arranging the first groove as a plurality of grooves along the thickness direction of the first wall portion, when forming the first groove, each stage of the groove can be processed one by one along the direction pointing from the first surface to the second surface, thereby reducing the forming depth of each stage of the groove, reducing the forming force applied to the pressure relief component when forming the first groove, and reducing the risk of the pressure relief component being damaged when forming the first groove. Since the projection of the first-level groove of the first groove along the width direction of the second groove overlaps at least partially with the projection of the second groove along the width direction of the second groove, the projection of the second groove in the width direction can cover the other levels of grooves in the first groove except the first-level groove. On the one hand, this can improve the absorption effect of the second groove on the excess material squeezed out of the first groove when the multi-level groove is processed. On the other hand, it can further improve the absorption effect of the second groove on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deformed, thereby reducing the influence of the expansion and deformation of the battery cell along the width direction of the second groove on the pressure relief component.

[0029] In some embodiments, along the thickness direction of the first wall portion, the bottom surface of the second groove is flush with the bottom surface of the first-stage groove, or the bottom surface of the second groove is closer to the first surface than the bottom surface of the first-stage groove. In this way, the projection of the second groove in the width direction can cover all the grooves of the first groove except the first-stage groove. This can, on the one hand, improve the second groove's ability to absorb excess material squeezed out of the first groove during the multi-stage groove forming process. On the other hand, it can improve the second groove's ability to absorb deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deforms, thereby reducing the impact of the battery cell's expansion and deformation along the width direction of the second groove on the pressure relief component.

[0030] In some embodiments, the pressure relief component has a first surface and a second surface facing each other along the thickness direction of the first wall portion, and the first groove and the second groove are both recessed from the second surface toward the first surface. Thus, the first groove and the second groove are disposed on the same side of the pressure relief component in the thickness direction, making it easier to machine the first groove and the second groove on the pressure relief component. The first groove and the second groove can be machined without flipping the pressure relief component, thereby optimizing the production cycle of battery cells.

[0031] In some embodiments, the first groove includes a plurality of grooves arranged in sequence along a direction from the second surface to the first surface, and along the thickness direction of the first wall portion, in two adjacent grooves, the first groove farther from the second surface is arranged at the groove bottom surface of the first groove closer to the second surface; wherein, among the multi-stage grooves, the first groove arranged on the second surface is a first-stage groove, and along the thickness direction of the first wall portion, the groove bottom surface of the first-stage groove is closer to the second surface than the groove bottom surface of the second groove. By arranging the first groove as a plurality of grooves along the thickness direction of the first wall portion, when forming the first groove, each stage of the groove can be processed one by one along the direction from the second surface to the first surface, thereby reducing the forming depth of each stage of the groove, reducing the forming force applied to the pressure relief component when forming the first groove, and reducing the risk of the pressure relief component being damaged when forming the first groove. Since the bottom surface of the first-level groove is closer to the second surface than the bottom surface of the second groove, the projection of the second groove along the width direction at least covers the first-level groove of the first groove, so that the second groove has a deeper depth, so that the second groove can have a good absorption effect on the excess material squeezed out when forming the first-level groove, and the second groove can have a good absorption effect on the deformation energy of the battery cell when the battery cell is subjected to internal and external impact forces and deformed.

[0032] In some embodiments, along the thickness direction of the first wall portion, the maximum groove depth of the second groove is H2, and the maximum groove depth of the first groove is H3, satisfying the following: H3 < H2. This greater depth of the second groove effectively absorbs excess material extruded during the formation of the first groove and effectively absorbs deformation energy of the battery cell when the battery cell is deformed by internal and external impact forces.

[0033] In some embodiments, the first surface is the surface of the pressure relief component facing the outside of the battery cell, and the second surface is the surface of the pressure relief component facing the inside of the battery cell. The first surface is the surface of the pressure relief component facing the outside of the battery cell. When the first groove is provided on the first surface, the first groove is provided on the outside of the pressure relief component, which facilitates the processing and forming of the first groove on the outside of the battery cell, and helps to reduce the difficulty of forming the first groove, thereby improving the production efficiency of the battery cell. The second surface is the surface of the pressure relief component facing the inside of the battery cell. When the second groove is provided on the second surface, the second groove is provided on the inside of the pressure relief component. On the one hand, when the predetermined pressure relief area is flipped outward and opened, the two groove sides in the width direction of the second groove are not easily abutted, which helps to increase the opening area of ​​the predetermined pressure relief area; on the other hand, the second groove is not exposed to the outside of the battery cell, reducing the risk of oxidation and corrosion of the pressure relief component in the second groove area.

[0034] In some embodiments, along the thickness direction of the first wall, the projection of the first groove, the projection of the second groove, and the projection of the extension of the second groove collectively enclose a predetermined pressure relief area; or, along the thickness direction of the first wall, the projection of the first groove, the projection of the extension of the first groove, and the projection of the second groove collectively enclose a predetermined pressure relief area; or, along the thickness direction of the first wall, the projection of the first groove, the projection of the extension of the first groove, the projection of the second groove, and the projection of the extension of the second groove collectively enclose a predetermined pressure relief area. This structure ensures that the projection of the second groove along the thickness direction of the first wall does not form a closed structure with the projection of the first groove along the thickness direction of the first wall, thereby reducing the mutual influence between the first and second grooves during the processing process.

[0035] In some embodiments, the first groove extends along an arcuate trajectory; and / or the second groove extends along a straight trajectory. The first groove extending along an arcuate trajectory, i.e., the first groove is an arcuate groove. This structure of the first groove comprises only one groove segment, simplifying the structure of the first groove. The second groove extending along a straight trajectory, i.e., the second groove is a straight groove, which has a simple structure and is easy to process and form.

[0036] In some embodiments, the first groove includes a first groove section and a second groove section, the first groove section being connected to the second groove section; along the thickness direction of the first wall, the projection of the first groove section, the projection of the second groove section, the projection of the second groove section, and the projection of the extension of the second groove section collectively enclose a predetermined pressure relief area; or, along the thickness direction of the first wall, the projection of the first groove section, the projection of the extension of the first groove section, the projection of the second groove section, the projection of the extension of the second groove section, and the projection of the second groove section collectively enclose a predetermined pressure relief area; or, along the thickness direction of the first wall, the projection of the first groove section, the projection of the extension of the first groove section, the projection of the second groove section, the projection of the extension of the second groove section, the projection of the second groove section, and the projection of the extension of the second groove collectively enclose a predetermined pressure relief area. This structure of the first groove is simple, and the stress at the connection between the first and second groove sections is more concentrated, making it weaker and more prone to cracking. This allows the pressure relief component to quickly crack from the first and second groove sections after cracking from the connection between the first and second groove sections during thermal runaway of the battery cell, allowing the predetermined pressure relief area to open more quickly and release pressure in a timely manner.

[0037] In some embodiments, the first groove includes a first groove section, a second groove section and a third groove section, the second groove section and the third groove section are arranged opposite to each other, the first groove section connects the second groove section and the third groove section, and the first groove section and the second groove are arranged opposite to each other; along the thickness direction of the first wall portion, the projection of the first groove section, the projection of the second groove section, the projection of the third groove section, the projection of the second groove and the projection of the extension line of the second groove together enclose a predetermined pressure relief area; or, along the thickness direction of the first wall portion, the projection of the first groove section, the projection of the second groove section, the projection of the extension line of the second groove section, the projection of the third groove section, the projection of the extension line of the third groove section and the projection of the second groove together enclose a predetermined pressure relief area; or, along the thickness direction of the first wall portion, the projection of the first groove section, the projection of the second groove section, the projection of the extension line of the second groove section, the projection of the third groove section, the projection of the extension line of the third groove section, the projection of the second groove and the projection of the extension line of the second groove together enclose a predetermined pressure relief area. The first groove with this structure makes the intersection of the first groove segment and the second groove segment and the connection position of the first groove segment and the third groove segment weaker, making it easier to crack and open the predetermined pressure relief area for pressure relief, and can further increase the opening area of ​​the predetermined pressure relief area, thereby increasing the pressure relief area of ​​the battery cell and improving the pressure relief rate of the battery cell.

[0038] In some embodiments, the connection position between the second groove section and the first groove section is offset from both ends of the second groove section, and the connection position between the third groove section and the first groove section is offset from both ends of the third groove section, so that predetermined pressure relief areas are formed on both sides of the first groove section. In this way, the first groove section of the first groove is located between the two predetermined pressure relief areas. After the pressure relief component is split along the first groove section, the two predetermined pressure relief areas can open in a split manner to relieve pressure when the battery cell releases pressure. This allows the two predetermined pressure relief areas to open quickly, which is beneficial for improving the pressure relief rate of the battery cell.

[0039] In some embodiments, the first slot segment extends along a straight line or an arcuate trajectory; and / or the second slot segment extends along a straight line or an arcuate trajectory; and / or the third slot segment extends along a straight line or an arcuate trajectory. If the first slot segment extends along a straight line, the first slot segment is a straight slot, which can reduce the difficulty of forming the first slot segment. If the first slot segment extends along an arcuate trajectory, the first slot segment is an arcuate slot, and the pressure relief component is more likely to split along the first slot segment when the battery cell is depressurized, thereby achieving a faster opening of the predetermined pressure relief area. If the second slot segment extends along a straight line, the second slot segment is a straight slot, which can reduce the difficulty of forming the second slot segment. If the second slot segment extends along an arcuate trajectory, the second slot segment is an arcuate slot, and the pressure relief component is more likely to split along the second slot segment when the battery cell is depressurized, thereby achieving a faster opening of the predetermined pressure relief area. If the third slot segment extends along a straight line, the third slot segment is a straight slot, which can reduce the difficulty of forming the third slot segment. If the third groove section extends along an arc trajectory, the third groove section is an arc-shaped groove, and the pressure relief component is more likely to split along the third groove section when the battery cell releases pressure, thereby achieving faster opening of the predetermined pressure relief area.

[0040] In some embodiments, the pressure relief component is integrally formed with the first wall portion, so that the first groove and the second groove can be directly formed on the first wall portion, forming an integrated pressure relief structure, which has higher reliability, eliminates the installation process of the pressure relief component, and has better economy.

[0041] In some embodiments, the first groove is stamped into the first wall; and / or the second groove is stamped into the first wall. If the first groove is stamped into the first wall, the first groove is formed in a simpler manner, which helps reduce the production cost of the battery cell. If the second groove is stamped into the first wall, the second groove is formed in a simpler manner, which helps reduce the production cost of the battery cell.

[0042] In some embodiments, the pressure relief component is separately provided with the first wall portion and is mounted on the first wall portion. The pressure relief component is a component independent of the housing, and the pressure relief component and the housing can be produced and assembled separately, which is easy to produce and efficient.

[0043] In some embodiments, the first wall portion is a rectangular wall portion, and the first groove and the second groove are arranged along the width direction of the first wall portion. In this way, the second groove is closer to the edge of the first wall portion in the width direction of the first wall portion, so that the area where the second groove is set in the pressure relief component has higher strength, reducing the risk of the pressure relief component cracking along the second groove when the battery cell releases pressure. In addition, during the use of the battery cell, the amount of expansion of the battery cell in the width direction of the first wall portion is greater than the amount of expansion in the length direction of the first wall portion. The expansion of the battery cell in the width direction of the first wall portion has a greater impact on the pressure relief component. The first groove and the second groove are arranged along the width direction of the first wall portion. The second groove can effectively absorb the deformation energy of the battery cell when the battery cell expands and deforms along the width direction of the first wall portion, thereby reducing the impact of the expansion of the battery cell along the width direction of the first wall portion on the pressure relief component.

[0044] In some embodiments, the housing includes a shell and an end cap; an opening is formed at least at one end of the shell; the end cap corresponds to the opening one-to-one, and the end cap closes the opening; wherein at least one end cap is a first wall portion; and / or at least one wall portion in the shell is a first wall portion. If at least one end cap is a first wall portion, so that at least one end cap has a pressure relief function, the difficulty of forming the first groove and the second groove on the end cap or the difficulty of installing the pressure relief component is lower. If at least one wall portion in the shell is a first wall portion, so that the shell has a pressure relief function, when the battery cell is depressurized, the emissions discharged from the inside of the battery cell are less likely to affect the external components outside the end cap, reducing the risk of external components being damaged by the emissions.

[0045] In some embodiments, the housing has an opening at only one end, and the wall of the housing opposite the end cap is the first wall. This single-end opening simplifies the overall battery cell structure. The first wall, the wall of the housing opposite the end cap, allows for directional pressure relief from the bottom of the housing.

[0046] In some embodiments, the housing has openings at both opposing ends, and at least one wall portion of the housing is a first wall portion. The housing has openings at both opposing ends, and the electrode assembly can be assembled into the housing through either opening, which can reduce the difficulty of assembling the battery cells and improve the assembly quality of the battery cells. This housing structure can be made longer (the housing has openings at both ends in the longitudinal direction), which helps increase the capacity of the battery cells.

[0047] In some embodiments, the pressure relief component is made of steel. Steel has high strength, and the pressure relief component made of steel has better strength. Under a certain bursting pressure of the battery cell, the pressure relief component can be made thinner, reducing the volume of the pressure relief component.

[0048] In some embodiments, the steel material is carbon steel or stainless steel.

[0049] In some embodiments, the pressure relief component is made of aluminum alloy, which is lightweight and ductile, making it easier to machine the first groove and the second groove on the pressure relief component.

[0050] In some embodiments, the aluminum alloy includes the following composition by weight: 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%. This aluminum alloy has lower hardness and better formability, reduces the difficulty of machining the first and second grooves, improves the machining accuracy of the first and second grooves, and enhances the pressure relief consistency of the pressure relief component.

[0051] In some embodiments, the aluminum alloy includes the following composition by weight: aluminum ≥ 96.7%, copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other individual elements ≤ 0.05%, and other elements combined ≤ 0.15%. Pressure relief components made from this aluminum alloy have increased hardness, strength, and excellent damage resistance.

[0052] In a second aspect, an embodiment of the present application provides a battery, comprising a battery cell provided by any embodiment of the first aspect.

[0053] In a third aspect, an embodiment of the present application provides an electrical device, comprising a battery cell provided by any one embodiment of the first aspect, wherein the battery cell is used to provide electrical energy to the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] 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.

[0055] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0056] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0057] FIG3 is an exploded view of a battery cell provided in some embodiments of the present application;

[0058] FIG4 is an assembly diagram of the battery cell shown in FIG3 ;

[0059] FIG5 is a partial view of the housing shown in FIG4 ;

[0060] FIG6 is a cross-sectional view taken along line AA of the housing shown in FIG5 ;

[0061] FIG7 is a partial enlarged view of point B in FIG6;

[0062] FIG8 is an assembly diagram of battery cells provided in some other embodiments of the present application;

[0063] FIG9 is a partial view of the housing shown in FIG8;

[0064] FIG10 is a CC sectional view of the housing shown in FIG9 ;

[0065] FIG11 is a partial enlarged view of point D in FIG10 ;

[0066] FIG12 is a partial cross-sectional view of a housing provided in some embodiments of the present application;

[0067] FIG13 is a partial enlarged view of point E in FIG12;

[0068] FIG14 is a partial view of a housing (the first groove is an arc-shaped groove) provided in some embodiments of the present application;

[0069] FIG15 is a sectional view taken along line FF of the housing shown in FIG14 ;

[0070] FIG16 is a partial view of a housing (the first groove is an arc-shaped groove) provided in some other embodiments of the present application;

[0071] FIG17 is a partial view of a housing (the first groove is an arc-shaped groove) provided in some other embodiments of the present application;

[0072] FIG18 is a partial view of a housing (the first groove is a V-shaped groove) provided in some embodiments of the present application;

[0073] FIG19 is a cross-sectional view taken along line GG of the housing shown in FIG18 ;

[0074] FIG20 is a partial view of a housing (the first groove is a V-shaped groove) provided in some other embodiments of the present application;

[0075] FIG21 is a partial view of a housing (the first groove is a V-shaped groove) provided in some other embodiments of the present application;

[0076] FIG22 is a partial view of a housing (the first groove is an H-shaped groove) provided in some other embodiments of the present application;

[0077] FIG23 is a partial view of a housing (the first groove is an H-shaped groove) provided in some other embodiments of the present application;

[0078] FIG24 is an exploded view of a housing (an opening is formed at one end of the housing, the housing includes a first wall portion, and the pressure relief component is the first wall portion) provided in some embodiments of the present application;

[0079] FIG25 is an exploded view of a housing (an opening is formed at one end of the housing, the housing includes a first wall portion, and a pressure relief component is mounted on the first wall portion) provided in some embodiments of the present application;

[0080] FIG26 is an exploded view of a housing (an opening is formed at one end of the housing, and the end cover is a pressure relief component) provided in some embodiments of the present application;

[0081] FIG27 is an exploded view of a housing (an opening is formed at one end of the housing, the end cover is a first wall portion, and a pressure relief component is installed on the first wall portion) provided in some embodiments of the present application;

[0082] FIG28 is an exploded view of a battery cell provided in some other embodiments of the present application.

[0083] Icons: 1-housing; 11-shell; 12-end cap; 13-first wall; 131-pressure relief hole; 14-second wall; 15-third wall; 2-electrode assembly; 21-electrode tab; 3-electrode terminal; 4-current collecting member; 5-insulating member; 6-pressure relief member; 61-first groove; 61a-extension line of the first groove; 611-first groove section; 612-second groove section; 613-third groove section; 614-bottom surface of the first groove; 615-first groove; 62-second groove; 62a-second groove Extension line of the groove; 621-side of the first groove; 622-side of the second groove; 623-first end; 624-second end; 625-bottom surface of the groove of the second groove; 63-predetermined pressure relief area; 64-first surface; 65-second surface; 10-battery cell; 20-housing; 201-first part; 202-second part; 100-battery; 200-controller; 300-motor; 1000-vehicle; X-thickness direction of the first wall; Y-extension direction of the second groove; Z-width direction of the second groove. DETAILED DESCRIPTION

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] The term "plurality" used in this application refers to two or more (including two).

[0091] 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.

[0092] Battery cells include but are not limited to lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0093] 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, active ions (such as lithium ions) move back and forth between the positive and negative electrodes. A separator, placed between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0094] 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.

[0095] 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.

[0096] 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.).

[0097] 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 / 3O2 (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 0.05 O2) and at least one of its modified compounds, etc.

[0098] In some embodiments, a positive electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, among others. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0099] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0100] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, the metal foil may be silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium. The metal foam may be nickel foam, copper foam, aluminum foam, or alloy foam. The composite current collector may include a polymer 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, or silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical and mechanical stability.

[0106] 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.

[0107] 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.

[0108] 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.

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

[0110] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, 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.

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

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

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

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

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

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

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

[0118] As an example, 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.

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

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

[0121] 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.

[0122] 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.

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

[0124] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0125] 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.

[0126] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. Prismatic battery cells include square-shell battery cells, blade-shaped battery cells, and polygonal prismatic batteries. Polygonal prismatic batteries are, for example, hexagonal prismatic batteries.

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

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

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

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

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

[0132] The development of battery technology must take into account multiple design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery reliability must also be considered.

[0133] In order to improve the reliability of battery cells, a pressure relief component can generally be provided in the battery cells. The pressure relief component can be a part of the battery cell shell or a component installed on the shell. When the battery cell thermally runs away, the pressure inside the battery cell can be released through the pressure relief component.

[0134] In order to achieve timely pressure relief of the battery cell, a pressure relief groove can be provided on the pressure relief component so that the pressure relief component can be split along at least a portion of the pressure relief groove when the battery cell is relieved of pressure, so that the pressure relief area of ​​the pressure relief component can be quickly opened to release the pressure inside the battery cell more quickly.

[0135] To make the pressure relief area of ​​the pressure relief component easier to open, a flip groove can be provided in the pressure relief component. The flip groove helps open the pressure relief area of ​​the pressure relief component, thereby reducing the difficulty of opening the pressure relief area. The provision of the flip groove weakens the ability of the excess material squeezed out of the pressure relief groove to diffuse toward the outer surface of the battery cell along the width direction of the flip groove. As a result, a large portion of the excess material squeezed out of the area where the pressure relief groove is provided in the pressure relief component will accumulate within the predetermined pressure relief area defined by the flip groove and the pressure relief groove, forming a material pile protrusion on the surface of the predetermined pressure relief area. This will affect the flatness of the surface of the pressure relief component where the pressure relief groove is provided, affect the production quality of the battery cell, and even affect the performance of the battery cell.

[0136] Based on the above considerations, in order to solve the problem of low production quality of battery cells, an embodiment of the present application provides a battery cell, which includes a housing and a pressure relief component. The housing includes a first wall portion, and the pressure relief component is arranged on the first wall portion. The pressure relief component includes a first groove (pressure relief groove) and a second groove (flip groove). Along the thickness direction of the first wall portion, the projection of the first groove and the projection of at least one second groove jointly define at least one predetermined pressure relief area. The pressure relief component is configured to be able to split along at least a portion of the first groove when the battery cell is depressurized, and the second groove is configured to guide at least a portion of the predetermined pressure relief area to flip to open at least a portion of the predetermined pressure relief area. Wherein, the volume of the first groove is V, the sum of the areas of all predetermined pressure relief areas is A, and the following conditions are satisfied: 0.05mm≤V / A≤0.5mm.

[0137] In such a battery cell, V / A≤0.5mm, so that when forming the first groove, the excess material squeezed out from the area where the first groove is set in the pressure relief component can be shared by the larger predetermined pressure relief area, reducing the amount of material piled per unit area of ​​the predetermined pressure relief area, so that the height of the material pile protrusion formed on the surface of the predetermined pressure relief area due to the squeezing of the material in the area where the first groove is set in the pressure relief component is not too large. On the one hand, the flatness of the surface of the pressure relief component where the first groove is set is improved, and on the other hand, the risk of releasing large residual stress during normal use of the battery cell due to the excessive height of the material pile protrusion in the predetermined pressure relief area, resulting in reduced fatigue strength of the pressure relief component, thereby improving the service life of the battery cell; V / A≥0.05mm, so that the height of the material pile protrusion formed on the surface of the predetermined pressure relief area 63 due to the squeezing of the material in the area where the first groove is set in the pressure relief component is not too small, and the residual stress released by the material pile protrusion helps the pressure relief component to crack along the first groove more promptly when the battery cell thermal runaway occurs, thereby improving the timeliness of pressure relief of the battery cell, reducing the risk of explosion of the battery cell, and thus improving the reliability of the battery cell. Therefore, 0.05mm≤V / A≤0.5mm can not only improve the flatness of the surface of the pressure relief component where the first groove is set, improve the production quality of the battery cell, but also take into account the service life requirements of the battery cell during normal use and the reliability requirements of the battery cell during thermal runaway.

[0138] The battery cells described in the embodiments of the present application are suitable for batteries and electrical equipment using the battery cells.

[0139] Electrical equipment can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and electric tools, etc. Vehicles can be fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical equipment.

[0140] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0141] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of the present application. A battery 100 is disposed within vehicle 1000. Battery 100 can be located at the bottom, front, or rear of vehicle 1000. Battery 100 can be used to power vehicle 1000, for example, as an operating power source for vehicle 1000.

[0142] The vehicle 1000 may further include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0143] In some embodiments of the present application, the battery 100 can not only serve as the operating 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.

[0144] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a battery cell 10 and a housing 20, wherein the battery cell 10 is accommodated in the housing 20.

[0145] The housing 20 is a component that houses the battery cells 10 and provides a storage space for the battery cells 10. The housing 20 can have various structures. In some embodiments, the housing 20 can include a first portion 201 and a second portion 202, which overlap to define a storage space for the battery cells 10. The first portion 201 and the second portion 202 can have various shapes, such as a rectangular parallelepiped or a cylindrical shape. The first portion 201 can be a hollow structure with one side open, and the second portion 202 can also be a hollow structure with one side open. The open side of the second portion 202 overlaps the open side of the first portion 201, thereby forming the housing 20 with a storage space. Alternatively, the first portion 201 can be a hollow structure with one side open, and the second portion 202 can be a plate-like structure. The second portion 202 overlaps the open side of the first portion 201, thereby forming the housing 20 with a storage space. The first portion 201 and the second portion 202 can be sealed by a sealing element, which can be a sealing ring, sealant, etc.

[0146] In the battery 100, there can be one or more battery cells 10. If there are multiple battery cells 10, the multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 10. Multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection to form a battery module, which can then be connected in series, parallel, or in a hybrid connection to form a single unit and housed within the housing 20. Alternatively, all battery cells 10 can be directly connected in series, parallel, or in a hybrid connection, and then the entire unit formed by all battery cells 10 can be housed within the housing 20.

[0147] Please refer to Figure 3, which is an exploded view of a battery cell 10 provided in some embodiments of the present application. The battery cell 10 may include a housing 1 and an electrode assembly 2, wherein the electrode assembly 2 is accommodated in the housing 1.

[0148] In some embodiments, the housing 1 may include a shell 11 and an end cover 12 , wherein the shell 11 has an opening and the end cover 12 closes the opening of the shell 11 .

[0149] The housing 11 is a component for accommodating the electrode assembly 2. The housing 11 can be a hollow structure with an opening at one end, or a hollow structure with openings at opposite ends. The housing 11 can have various shapes, such as a cylinder or a rectangular parallelepiped. The housing 11 can be made of various materials, such as copper, iron, aluminum, steel, and aluminum alloys.

[0150] The end cap 12 is a component that closes the opening of the shell 11 to isolate the internal environment of the battery cell 10 from the external environment. The end cap 12 and the shell 11 together define a receiving space for accommodating the electrode assembly 2, electrolyte and other components. The end cap 12 can be connected to the shell 11 by welding or rolling to close the opening of the shell 11. The shape of the end cap 12 can be adapted to the shape of the shell 1. For example, the shell 11 is a rectangular parallelepiped structure, and the end cap 12 is a rectangular plate structure adapted to the shell 1. For another example, the shell 11 is a cylindrical structure, and the end cap 12 is a circular plate structure adapted to the shell 11. The material of the end cap 12 can also be a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The material of the end cap 12 and the shell 11 can be the same or different.

[0151] In an embodiment where the housing 11 is open at one end, one end cap 12 may be provided. In an embodiment where the housing 11 is open at two opposite ends, two end caps 12 may be provided, each of which closes the two openings of the housing 11, and the two end caps 12 and the housing 11 together define a receiving space.

[0152] In some embodiments, the battery cell 10 may further include an electrode terminal 3, which is disposed on the outer casing 1. The electrode terminal 3 is used to electrically connect to the tab 21 of the electrode assembly 2 to input or output electrical energy from the battery cell 10. The electrode terminal 3 may be disposed on the shell 11 of the outer casing 1 or on the end cap 12 of the outer casing 1. The electrode terminal 3 and the tab 21 may be directly connected, for example, by directly welding the electrode terminal 3 and the tab 21. The electrode terminal 3 and the tab 21 may also be indirectly connected, for example, by indirectly connecting the electrode terminal 3 and the tab 21 through a current collecting member 4. The current collecting member 4 may be a metal conductor, such as copper, iron, aluminum, steel, an aluminum alloy, or the like.

[0153] As an example, as shown in FIG3 , an opening is formed at one end of the housing 11. There is only one end cap 12 in the outer shell 1, and each end cap 12 closes the opening of the housing 11. Two electrode terminals 3 are provided on the end cap 12, which are respectively a positive electrode terminal and a negative electrode terminal. A positive electrode tab and a negative electrode tab are formed on the end of the electrode assembly 2 facing the end cap 12. The positive electrode terminal is connected to the positive electrode tab via a current collecting member 4, and the negative electrode terminal is connected to the negative electrode tab via another current collecting member 4.

[0154] 3 , the battery cell 10 may further include an insulating member 5 . The insulating member 5 is a component that separates the housing 11 from the electrode assembly 2 , thereby achieving insulation isolation between the housing 11 and the electrode assembly 2 . The insulating member 5 is made of an insulating material, including but not limited to plastic, rubber, and the like.

[0155] As an example, the insulating member 5 wraps around the outside of the electrode assembly 2 along the circumference of the opening of the housing 11. There can be one or more electrode assemblies 2 within the housing 1. If there is a single electrode assembly 2, the insulating member 5 wraps around it. If there are multiple electrode assemblies 2, one insulating member 5 can be provided for each electrode assembly 2, with each insulating member 5 wrapping around a single electrode assembly 2. Alternatively, multiple electrode assemblies 2 can be formed as a single integral component, with the insulating member 5 wrapping around the integral component.

[0156] Please refer to Figures 4 to 6. Figure 4 is an assembly diagram of the battery cell 10 shown in Figure 3. Figure 5 is a partial view of the housing 1 shown in Figure 4. Figure 6 is an AA cross-sectional view of the housing 1 shown in Figure 5. An embodiment of the present application provides a battery cell 10, comprising a housing 1 and a pressure relief component 6. The housing 1 comprises a first wall portion 13. The pressure relief component 6 is disposed on the first wall portion 13. The pressure relief component 6 comprises a first groove 61 and a second groove 62. Along the thickness direction of the first wall portion 13, the projection of the first groove 61 and the projection of at least one second groove 62 together define at least one predetermined pressure relief area 63. The pressure relief component 6 is configured to split along at least a portion of the first groove 61 when the battery cell 10 releases pressure. The second groove 62 is configured to guide at least a portion of the predetermined pressure relief area 63 to flip over, thereby opening at least a portion of the predetermined pressure relief area 63.

[0157] The volume of the first groove 61 is V, and the sum of the areas of all the predetermined pressure relief zones 63 is A, satisfying the following: 0.05 mm ≤ V / A ≤ 0.5 mm.

[0158] The outer shell 1 includes a plurality of wall portions, which together define a receiving space inside the outer shell 1 to accommodate the electrode assembly 2, the electrolyte and other components. The other components may be current collecting members 4, insulating members 5 and other components. Among the multiple wall portions of the outer shell 1, one wall portion may be the first wall portion 13, or multiple wall portions may be the first wall portion 13. It is understandable that, taking the outer shell 1 as a rectangular parallelepiped as an example, there are six walls in the outer shell 1, and one, two, three, four, five, or six walls may be the first wall portion 13. In the outer shell 1, at least one end cap 12 may be the first wall portion 13, or at least one wall portion in the shell 11 may be the first wall portion 13.

[0159] The pressure relief component 6 is a component in the battery cell 10 that is used to release the pressure inside the battery cell 10. The pressure relief component 6 can be integrally formed with the outer shell 1. It is understandable that a part of the outer shell 1 can serve as the pressure relief component 6. For example, the pressure relief component 6 is integrally formed with the end cover 12 of the outer shell 1; for another example, the pressure relief component 6 is integrally formed with a wall portion of the shell 11 of the outer shell 1. The pressure relief component 6 can also be provided separately from the outer shell 1. The pressure relief component 6 and the outer shell 1 are two separately produced components, and the pressure relief component 6 is installed on the outer shell 1. For example, the pressure relief component 6 is installed on the end cover 12 of the outer shell 1; for another example, the pressure relief component 6 is installed on the shell 11 of the outer shell 1.

[0160] The first groove 61 is a pressure relief groove provided in the pressure relief component 6. When the pressure inside the battery cell 10 reaches the burst pressure of the pressure relief component 6, the pressure relief component 6 can rupture along at least a portion of the first groove 61 to open a predetermined pressure relief area 63. It is understood that when the pressure in the battery cell 10 is released, the pressure relief component 6 can rupture along the entire first groove 61 or along a portion of the first groove 61. The first groove 61 can be formed in a variety of ways, such as by stamping or milling. The first groove 61 can include at least one groove segment, and the cross-section of the groove segment can have various shapes, such as rectangular or trapezoidal. The cross-section of the groove segment is perpendicular to the direction of extension of the groove segment. The first groove 61 can have various shapes, such as a groove extending along an arc trajectory. For example, the first groove 61 can include multiple groove segments, and the multiple groove segments can form a U-shaped, H-shaped, V-shaped, Y-shaped, X-shaped, T-shaped, or other structures.

[0161] The second groove 62 is a rotation groove provided in the pressure relief component 6. When the pressure relief component 6 ruptures along at least a portion of the first groove 61, the second groove 62 guides the rotation of at least a portion of the predetermined pressure relief area 63. In other words, the second groove 62 facilitates the rotation of the predetermined pressure relief area 63, making it easier for the predetermined pressure relief area 63 to rotate toward the outside of the battery cell 10, thereby quickly opening the predetermined pressure relief area 63. The second groove 62 can guide the rotation of the predetermined pressure relief area 63 in its entirety or only in a portion. During the pressure relief process of the battery cell 10, the pressure relief component 6 can rupture along at least a portion of the first groove 61, and generally does not rupture along the second groove 62. The minimum thickness of the remaining portion of the pressure relief component 6 in the area where the first groove 61 is provided can be smaller than the minimum thickness of the remaining portion of the pressure relief component 6 in the area where the second groove 62 is provided, making the pressure relief component 6 more likely to rupture in the area where the first groove 61 is provided than in the area where the second groove 62 is provided. The second groove 62 can be formed in various ways, such as by stamping, milling, etc. The second groove 62 can have various shapes, such as a groove extending along an arc trajectory, or a groove extending along a straight trajectory. The cross-sectional shape of the second groove 62 can be various shapes, such as a rectangle, a trapezoid, etc.

[0162] The second groove 62 not only facilitates the flipping of the predetermined pressure relief area 63 but also provides a buffering function. The second groove 62 absorbs any excess material extruded during the molding of the first groove 61, reducing the risk of the material from the first groove 61 spreading to the surface of the housing 1 along the width direction Z of the second groove, thereby improving the surface smoothness of the housing 1 along the width direction Z of the second groove. When the housing 1 of the battery cell 10 is subjected to internal and external impact forces and deforms along the width direction Z of the second groove, the second groove 62 can absorb the deformation energy of the housing 1, reducing the impact of the expansion and deformation of the battery cell 10 along the width direction Z of the second groove on the pressure relief component 6.

[0163] The second groove 62 and the first groove 61 can be arranged on the same surface of the pressure relief component 6 along the thickness direction X of the first wall portion, or the second groove 62 and the first groove 61 can be respectively arranged on two opposite surfaces of the pressure relief component 6 along the thickness direction X of the first wall portion. The second groove 62 and the first groove 61 can be directly connected, or the second groove 62 and the first groove 61 can not contact each other. If the second groove 62 and the first groove 61 are directly connected, the second groove 62 and the first groove 61 can be arranged on the same surface of the pressure relief component 6, or the second groove 62 and the first groove 61 can jointly enclose a predetermined pressure relief area 63. If the second groove 62 and the first groove 61 do not contact each other, the projection of the second groove 62 and the projection of the first groove 61 along the thickness direction X of the first wall portion can partially overlap or not overlap. If the projection of the second groove 62 does not overlap with the projection of the first groove 61 along the thickness direction X of the first wall portion, the projection of the second groove 62, the projection of the extension line 62a of the second groove, and the projection of the first groove 61 may jointly enclose a predetermined pressure relief area 63; or the projection of the first groove 61, the projection of the extension line 61a of the first groove, and the projection of the second groove 62 may jointly enclose a predetermined pressure relief area 63; or the projection of the first groove 61, the projection of the extension line 61a of the first groove, the projection of the second groove 62, and the projection of the extension line 62a of the second groove may jointly enclose a predetermined pressure relief area 63.

[0164] The predetermined pressure relief area 63 is an area defined by the projection of the pressure relief component 6 along the thickness direction X of the first wall portion by the first groove 61 and the at least one second groove 62. Along the thickness direction X of the first wall portion, the projection of the first groove 61 and the projection of the second groove 62 may define a predetermined pressure relief area 63. For example, the first groove 61 is a V-shaped groove, and the second groove 62 is a linear groove. Along the thickness direction X of the first wall portion, the projection of the first groove 61 and the projection of the second groove 62 may define multiple predetermined pressure relief areas 63. For example, the first groove 61 is an H-shaped groove, and the second groove 62 is an annular groove. The first groove 61 is located in the circular area defined by the second groove 62. Along the thickness direction X of the first wall portion, the projection of the first groove 61 and the projection of the second groove 62 may define multiple predetermined pressure relief areas 63. For example, the first groove 61 is an H-shaped groove, and the second groove 62 is an annular groove. The first groove 61 is located in the circular area defined by the second groove 62. The projection of the groove 61 and the projection of the multiple second grooves 62 define a predetermined pressure relief area 63. For example, the first groove 61 is an H-shaped groove, the second groove 62 is a linear groove, and the multiple second grooves 62 are arranged at intervals along the extension direction of the second groove 62 and are located on the same side of the first groove 61; along the thickness direction X of the first wall portion, the projection of the first groove 61 and the projection of the multiple second grooves 62 can also define three or more predetermined pressure relief areas 63. For example, the first groove 61 is an H-shaped groove, the second groove 62 is a linear groove, and the first groove 61 is located between two second grooves 62.

[0165] The predetermined pressure relief area 63 can be triangular, rectangular, trapezoidal, semicircular, or other shapes. Along the thickness direction X of the first wall portion, the pressure relief component 6 has a first surface 64 and a second surface 65 that oppose each other. One of the first surface 64 and the second surface 65 is the outer surface of the pressure relief component 6, and the other is the inner surface of the pressure relief component 6. For example, if the first groove 61 is provided on the first surface 64, the portion of the first surface 64 located in the predetermined pressure relief area 63 is the measurement surface of the predetermined pressure relief area 63. The area of ​​the predetermined pressure relief area 63 is the area of ​​the measurement surface of the predetermined pressure relief area 63. Taking the example of the projection of the first groove 61, the projection of the extension line 61a of the first groove, and the projection of the second groove 62, which together enclose the predetermined pressure relief zone 63, the edge of the measurement surface of the predetermined pressure relief zone 63 can be formed by connecting the projection of the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side closest to the predetermined pressure relief zone 63) on the first surface 64, the projection of the inner edge of the notch of the first groove 61 (the edge of the notch of the first groove 61 on the side closest to the predetermined pressure relief zone 63) on the first surface 64, and the projection of the extension line of the inner edge of the notch of the first groove 61 on the first surface 64. By measuring the area of ​​the measurement surface of the predetermined pressure relief zone 63, the area of ​​the predetermined pressure relief zone 63 can be obtained. Taking the example of the first groove 61 being provided on the second surface 65, the portion of the second surface 65 located in the predetermined pressure relief zone 63 is the measurement surface of the predetermined pressure relief zone 63. The area of ​​the predetermined pressure relief zone 63 is the area of ​​the measurement surface of the predetermined pressure relief zone 63. Taking the projection of the first groove 61, the projection of the extension line 61a of the first groove and the projection of the second groove 62 together to enclose the predetermined pressure relief area 63 as an example, the edge of the measuring surface of the predetermined pressure relief area 63 can be formed by the projection of the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side close to the predetermined pressure relief area 63) on the second surface 65, the projection of the inner edge of the notch of the first groove 61 (the edge of the notch of the first groove 61 on the side close to the predetermined pressure relief area 63) in the second surface 65 and the projection of the extension line of the inner edge of the notch of the first groove 61 in the second surface 65. The area of ​​the predetermined pressure relief area 63 can be obtained by measuring the area of ​​the measuring surface of the predetermined pressure relief area 63. It should be noted that if the first groove 61 and the second groove 62 are both arranged on the first surface 64, the notch of the first groove 61 and the notch of the second groove 62 are both formed on the first surface 64; if the first groove 61 and the second groove 62 are both arranged on the second surface 65, the notch of the first groove 61 and the notch of the second groove 62 are both formed on the second surface 65; if the first groove 61 is arranged on the first surface 64 and the second groove 62 is arranged on the second surface 65, the notch of the first groove 61 is formed on the first surface 64, and the notch of the second groove 62 is formed on the second surface 65; if the first groove 61 is arranged on the second surface 65 and the second groove 62 is arranged on the first surface 64, the notch of the first groove 61 is formed on the second surface 65, and the notch of the second groove 62 is formed on the first surface 64.

[0166] As an example, in the embodiment shown in Figures 4-6, the thickness direction X of the first wall portion is parallel to the first direction. The wall portion of the housing 11 opposing the end cap 12 is the first wall portion 13, which serves as the pressure relief member 6. A first groove 61 and a second groove 62 are respectively provided on opposite surfaces of the pressure relief member 6 along the thickness direction X of the first wall portion. The first groove 61 is H-shaped, and the second groove 62 extends along a straight path. The extension direction Y of the second groove is parallel to the second direction, and the width direction Z of the second groove is parallel to the third direction. The first, second, and third directions are perpendicular to each other. The first direction is the height direction of the battery cell 10, the second direction is the length direction of the battery cell 10, and the third direction is the thickness direction of the battery cell 10. In Figure 5, there are two predetermined pressure relief areas 63, and the sum of the areas of the two shaded areas shown in Figure 5 is the sum of the areas of the two predetermined pressure relief areas 63.

[0167] The volume of the first groove 61 is the volume of the internal space of the first groove 61. If the first groove 61 includes only one groove segment, the volume of the groove segment is the volume of the first groove 61; if the first groove 61 includes multiple groove segments, the sum of the volumes of the multiple groove segments is the volume of the first groove 61. Taking the example of the first groove 61 including multiple groove segments, the volume of each groove segment can be measured first, and then the volume of all the groove segments can be added together to calculate the volume of the first groove 61. For a single groove segment, the length of the groove segment can be measured first, and then the pressure relief component 6 can be cut along a direction perpendicular to the extension of the groove segment, and the cross-sectional area of ​​the groove segment can be measured on the cut surface of the pressure relief component 6 (the cut surface should be as close as possible to the midpoint of the groove segment in the extension direction). Then, the length of the groove segment and the cross-sectional area of ​​the groove segment can be multiplied to calculate the volume of the groove segment. Taking the cross-sectional shape of the slot segment as an example, the slot depth and slot width of the slot segment can be measured on the upper side of the cross-section of the pressure relief component 6, and then the slot depth and slot width of the slot segment can be multiplied to calculate the cross-sectional area of ​​the slot segment. It should be noted that if the slot segment has rounded corners or chamfers at both ends of the extension direction, the volume of the slot segment is calculated by multiplying the length of the slot segment by the area of ​​the cross-sectional area of ​​the slot segment. The actual volume of the slot segment will be slightly smaller than the calculated volume, but the calculated volume of the slot segment can still be obtained by multiplying the length of the slot segment by the area of ​​the cross-sectional area of ​​the slot segment. The calculated volume is approximately equal to the actual volume of the slot segment. That is to say, when actually measuring the volume of the slot segment, the calculated volume of the slot segment obtained by calculation can be regarded as the actual volume of the slot segment.

[0168] It should be noted that in the embodiment of the present application, the sum of the areas of all predetermined pressure relief zones 63 is A. This does not limit the number of predetermined pressure relief zones 63 to multiple. The predetermined pressure relief zones 63 can be one or more. If there is only one predetermined pressure relief zone 63, the area of ​​the predetermined pressure relief zone 63 is the sum of the areas of all predetermined pressure relief zones 63.

[0169] V / A can take any point value among 0.05mm, 0.06mm, 0.08mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.38mm, 0.4mm, 0.42mm, 0.45mm, 0.46mm, 0.48mm, 0.5mm, etc., or a range value between any two of them.

[0170] In the embodiment of the present application, the pressure relief component 6 is provided with a first groove 61, so that the pressure relief component 6 can split along at least a portion of the first groove 61 when the battery cell 10 releases pressure, thereby releasing the internal pressure of the battery cell 10. The pressure relief component 6 is also provided with a second groove 62. The first groove 61 and the second groove 62 together define at least one predetermined pressure relief area 63. The second groove 62 can guide at least a portion of the predetermined pressure relief area 63 to flip over, thereby opening at least a portion of the predetermined pressure relief area 63 for pressure relief. The second groove 62 assists the predetermined pressure relief area 63, making it easier to flip over, reducing the difficulty of flipping the predetermined pressure relief area 63, and increasing the opening speed of the predetermined pressure relief area 63. V / A≤0.5mm, so that when forming the first groove 61, the excess material squeezed out from the area where the first groove 61 is set in the pressure relief component 6 can be shared by the larger predetermined pressure relief area 63, reducing the amount of material piled per unit area of ​​the predetermined pressure relief area 63, so that the height of the material piled bulge formed on the surface of the predetermined pressure relief area 63 due to the material squeezed in the area where the first groove 61 is set in the pressure relief component 6 is not too large, on the one hand, the flatness of the surface of the pressure relief component 6 where the first groove 61 is set is improved, and on the other hand, the material piled bulge in the predetermined pressure relief area 63 during normal use of the battery cell 10 due to the excessive height of the material piled bulge is reduced. The risk of releasing large residual stress during the heating process, which would reduce the fatigue strength of the pressure relief component 6, is increased, thereby improving the service life of the battery cell 10. V / A ≥ 0.05 mm ensures that the height of the material protrusion formed on the surface of the predetermined pressure relief area 63 due to material extrusion in the area where the first groove 61 of the pressure relief component 6 is provided is not too small. The residual stress released by the material protrusion helps the pressure relief component 6 to break along the first groove 61 more promptly when the battery cell 10 experiences thermal runaway, thereby improving the timeliness of the pressure relief of the battery cell 10, reducing the risk of battery cell 10 explosion, and thus improving the reliability of the battery cell 10. Therefore, 0.05 mm ≤ V / A ≤ 0.5 mm can not only improve the flatness of the surface of the first groove 61 of the pressure relief component 6 and improve the production quality of the battery cell 10, but also take into account the service life requirements of the battery cell 10 during normal use and the reliability requirements of the battery cell 10 during thermal runaway.

[0171] In some embodiments, 0.1 mm ≤ V / A ≤ 0.35 mm.

[0172] In this embodiment, V / A can take any point value among 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.34mm, 0.35mm, etc., or a range value between any two of them.

[0173] In this embodiment, V / A≤0.35mm, on the one hand, further improves the flatness of the surface of the first groove 61 of the pressure relief component 6, and on the other hand, further reduces the influence of the pile protrusion of the predetermined pressure relief area 63 on the fatigue strength of the pressure relief component 6; V / A≥0.1mm, further improves the timeliness of the pressure relief of the battery cell 10, and further reduces the risk of explosion of the battery cell 10.

[0174] In some embodiments, 82 mm 3 ≤V≤450mm 3 .

[0175] In this embodiment, V can be 82mm 3 , 90mm 3 , 100mm 3 , 115mm 3 , 120mm 3 , 150mm 3 , 153mm 3 , 180mm 3 , 184mm 3 , 200mm 3 , 210mm 3 , 250mm 3 , 265mm 3 , 285mm 3 , 300mm 3 , 350mm 3 , 400mm 3 , 450mm 3 Any point value or any range of values ​​between the two.

[0176] In this embodiment, V≤450mm 3 , so that the amount of material extruded during the formation of the first groove 61 is not too large, the forming force on the pressure relief component 6 during the formation of the first groove 61 is reduced, and the risk of damage to the pressure relief component 6 during the formation of the first groove 61 is reduced; V ≥ 82mm 3, so that the amount of extruded material when forming the first groove 61 will not be too small, it is easier to meet the depth, width and length requirements of the first groove 61, and the difficulty of forming the first groove 61 is reduced.

[0177] In some embodiments, 115 mm 3 ≤V≤265mm 3 .

[0178] In this embodiment, V can be 115mm 3 , 120mm 3 , 125mm 3 , 130mm 3 , 135mm 3 , 140mm 3 , 145mm 3 , 150mm 3 , 153mm 3 , 155mm 3 , 160mm 3 , 165mm 3 , 170mm 3 , 175mm 3 , 180mm 3 , 184mm 3 , 185mm 3 , 190mm 3 , 195mm 3 , 200mm 3 , 205mm 3 , 210mm 3 , 215mm 3 , 220mm 3 , 225mm 3 , 230mm 3 , 235mm 3 , 240mm 3 , 245mm 3 , 250mm 3 , 255mm 3 , 260mm 3 , 265mm 3 Any point value or any range of values ​​between the two.

[0179] In this embodiment, V≤265mm 3 , further reducing the amount of material extruded during the forming of the first groove 61, further reducing the forming force on the pressure relief component 6 during the forming of the first groove 61, and reducing the risk of damage to the pressure relief component 6 during the forming of the first groove 61; V ≥ 115mm 3, further increasing the amount of extrusion when forming the first groove 61, and further reducing the difficulty of forming the first groove 61.

[0180] In some embodiments, 160 mm 2 ≤A≤1500mm 2 .

[0181] In this embodiment, A can be 160 mm 2 , 200mm 2 , 250mm 2 , 300mm 2 , 320mm 2 , 400mm 2 , 450mm 2 , 500mm 2 , 550mm 2 , 600mm 2 、650mm 2 , 700mm 2 , 750mm 2 , 800mm 2 , 850mm 2 , 875mm 2 , 890mm 2 , 900mm 2 , 950mm 2 , 1000mm 2 , 1050mm 2 , 1100mm 2 , 1150mm 2 , 1200mm 2 , 1250mm 2 , 1300mm 2 , 1350mm 2 , 1400mm 2 、1437mm 2 , 1450mm 2 , 1500mm 2 Any point value or any range of values ​​between the two.

[0182] In this embodiment, A≤1500mm 2 , so that the area of ​​the predetermined pressure relief zone 63 is not too large, reducing the risk of the predetermined pressure relief zone 63 being deformed by the pressure change inside the battery cell 10 and causing the pressure relief component 6 to crack prematurely along the first groove 61; A ≥ 160mm 2 , so that the pressure relief component 6 has a sufficiently large pressure relief area, thereby improving the pressure relief rate of the battery cell 10.

[0183] In some embodiments, 400 mm 2≤A≤1200mm 2 .

[0184] In this embodiment, A can be 400mm 2 , 425mm 2 , 450mm 2 , 475mm 2 , 500mm 2 , 525mm 2 , 550mm 2 , 575mm 2 , 600mm 2 , 625mm 2 、650mm 2 、675mm 2 , 700mm 2 , 725mm 2 , 750mm 2 , 775mm 2 , 800mm 2 , 825mm 2 , 850mm 2 , 857mm 2 , 875mm 2 , 880mm 2 , 900mm 2 , 925mm 2 , 950mm 2 , 975mm 2 , 1000mm 2 , 1025mm 2 , 1050mm 2 , 1075mm 2 , 1100mm 2 , 1125mm 2 , 1150mm 2 , 1175mm 2 , 1200mm 2 Any point value or any range of values ​​between the two.

[0185] In this embodiment, A≤1200mm 2 , further reducing the risk of premature cracking of the pressure relief component 6 along the first groove 61. A≥400mm 2 , further improving the pressure release rate of the battery cell 10.

[0186] In some embodiments, please refer to Figures 6 and 7. Figure 7 is a partial enlarged view of point B in Figure 6. Along the thickness direction X of the first wall portion, the pressure relief component 6 has a first surface 64 and a second surface 65 opposite to each other. The second groove 62 is recessed from the second surface 65 toward the first surface 64. Along the width direction Z of the second groove, the second groove 62 includes a first groove side surface 621 and a second groove side surface 622 that are oppositely disposed and connected to the second surface 65. The first groove side surface 621 is closer to the predetermined pressure relief area 63 than the second groove side surface 622. The angle between the first groove side surface 621 and the second surface 65 is a, and the angle between the second groove side surface 622 and the second surface 65 is b, satisfying the following: 90°≤a<b<180°. The width direction Z of the second groove is perpendicular to the thickness direction X of the first wall portion.

[0187] When measuring angle a and angle b, the pressure relief component 6 can be cut perpendicularly to the extension direction of the second groove 62, and the angles between the first groove side surface 621 and the second surface 65, as well as the angles between the second groove side surface 622 and the second surface 65, can be measured on the cut surface using a measuring tool. Alternatively, a CT scanner can be used to scan and image the first groove side surface 621, the second groove side surface 622, and the second surface 65 on the cut surface, and then the angles between the first groove side surface 621 and the second surface 65, as well as the angles between the second groove side surface 622 and the second surface 65, can be measured.

[0188] One of the first surface 64 and the second surface 65 may be the outer surface of the pressure relief component 6, and the other may be the inner surface of the pressure relief component 6. The outer surface of the pressure relief component 6 faces the outside of the battery cell 10, and the inner surface of the pressure relief component 6 faces the inside of the battery cell 10. The first surface 64 and the second surface 65 may be planes. The first surface 64 and the second surface 65 may be arranged in parallel or at a non-zero angle. The second groove 62 is recessed from the second surface 65 toward the direction close to the first surface 64, that is, the second groove 62 is arranged on the second surface 65. In this case, the first groove 61 can be arranged on the second surface 65 or on the first surface 64. As an example, in the embodiment shown in Figure 7, the first surface 64 is the outer surface of the pressure relief component 6, the first groove 61 is arranged on the first surface 64, and the second groove 62 is arranged on the second surface 65.

[0189] The first groove side surface 621 can be a plane or an arc surface. If the first groove side surface 621 is an arc surface, the angle between the line connecting the two ends of the first groove side surface 621 along the depth direction of the second groove 62 and the second surface 65 is the angle a between the first groove side surface 621 and the second surface 65. The second groove side surface 622 can be a plane or an arc surface. If the second groove side surface 622 is an arc surface, the angle between the line connecting the two ends of the second groove side surface 622 along the depth direction of the second groove 62 and the second surface 65 is the angle b between the second groove side surface 622 and the second surface 65. The first groove side surface 621 and the second surface 65 can be directly connected or indirectly connected, for example, the first groove side surface 621 and the second surface 65 have a smooth transition through an arc surface; the second groove side surface 622 and the second surface 65 can be directly connected or indirectly connected, for example, the second groove side surface 622 and the second surface 65 have a smooth transition through an arc surface. As an example, in the embodiment shown in FIG. 7 , the second surface 65 , the first groove side surface 621 , and the second groove side surface 622 are all planes.

[0190] The first groove side surface 621 and the second surface 65 may be arranged at an obtuse angle or a right angle, and the second groove side surface 622 and the second surface 65 may be arranged at an obtuse angle. As an example, ba ≥ 3°.

[0191] The second groove 62 may further include a groove bottom surface. The groove bottom surface 625 of the second groove connects the first groove side surface 621 and the second groove side surface 622. The groove bottom surface 625 of the second groove may be a flat surface or an arcuate surface. As an example, the width of the second groove 62 gradually decreases along the depth direction of the second groove 62, and the groove bottom surface 625 of the second groove is a flat surface parallel to the second surface 65.

[0192] In this embodiment, a<b, is equivalent to reducing the angle between the first groove side 621 and the second surface 65, which can reduce the amount of excess material squeezed out when forming the second groove 62 in the predetermined pressure relief area 63, and reduce the height of the material piling protrusion formed on the surface of the predetermined pressure relief area 63 due to the squeezing of material in the area where the second groove 62 is set in the pressure relief component 6, thereby improving the flatness of the surface of the predetermined pressure relief area 63, reducing the influence of the material piling protrusion on the predetermined pressure relief area 63, and reducing the risk of the predetermined pressure relief area 63 opening prematurely due to the uneven surface of the predetermined pressure relief area 63.

[0193] In some embodiments, 90°≤a≤150°.

[0194] In this embodiment, a can take any point value among 90°, 100°, 110°, 120°, 130°, 135°, 140°, 150°, etc., or a range value between any two of them.

[0195] In this embodiment, 90°≤a≤150° further reduces the angle between the first groove side 621 and the second surface 65, further reducing the inclination angle of the first groove side 621, which is beneficial to reducing the amount of excess material extruded in the predetermined pressure relief area when forming the second groove 62.

[0196] In some embodiments, 90°<b≤170°.

[0197] In this embodiment, b can take any point value among 91°, 95°, 100°, 105°, 110°, 115°, 120°, 125°, 130°, 135°, 140°, 145°, 150°, 155°, 160°, 165°, 170°, etc., or a range value between any two of them.

[0198] In this embodiment, 90°<b<170°, which further reduces the angle between the second groove side surface 622 and the second surface 65 , further reduces the inclination angle of the second groove side surface 622 , and reduces the difficulty of forming the second groove 62 .

[0199] In some embodiments, please continue to refer to Figure 5. The pressure relief component 6 is provided with multiple second grooves 62. Along the thickness direction X of the first wall portion, the projection of the first groove 61 and the projection of the multiple second grooves 62 jointly define a plurality of predetermined pressure relief areas 63. Each predetermined pressure relief area 63 is corresponding to one or more second grooves 62.

[0200] Along the thickness direction X of the first wall portion, the projection of the first groove 61 and the projections of the plurality of second grooves 62 together define two, three, four, five, or more predetermined pressure relief areas 63. Each predetermined pressure relief area 63 can be provided corresponding to at least one second groove 62. In other words, each predetermined pressure relief area 63 can be provided corresponding to one second groove 62 or to multiple second grooves 62.

[0201] As an example, in the embodiment shown in Figure 5, the predetermined pressure relief areas 63 correspond one-to-one to the second grooves 62. Along the thickness direction X of the first wall portion, the projection of the first groove 61 and the projections of the two second grooves 62 jointly define two predetermined pressure relief areas 63, and the two predetermined pressure relief areas 63 are symmetrically arranged.

[0202] In this embodiment, the first groove 61 and the plurality of second grooves 62 jointly define a plurality of predetermined pressure relief areas 63. When the battery cell 10 thermally runs away, the plurality of predetermined pressure relief areas 63 can all be opened. When the total pressure relief area of ​​the pressure relief component 6 is constant, the opening rate of the predetermined pressure relief areas 63 can be increased, and pressure relief can be achieved more quickly.

[0203] In some embodiments, please continue to refer to FIG. 5 to FIG. 7 , along the thickness direction X of the first wall portion, the projection of the second groove 62 does not overlap with the projection of the first groove 61 .

[0204] It can be understood that, along the thickness direction X of the first wall portion, the projection of the second groove 62 has no overlapping portion with the projection of the first groove 61 .

[0205] Along the thickness direction X of the first wall portion, the projection of the extension line 62a of the second groove may be connected to the projection of the first groove 61, or the projection of the extension line 61a of the first groove may be connected to the projection of the second groove 62, or the projection of the extension line 61a of the first groove may be connected to the projection of the extension line 62a of the second groove.

[0206] The second groove 62 and the first groove 61 can be arranged on the same side of the pressure relief component 6 in the thickness direction X of the first wall portion, for example, the second groove 62 and the first groove 61 are both arranged on the first surface 64, and for another example, the second groove 62 and the first groove 61 are both arranged on the second surface 65; the second groove 62 and the first groove 61 can also be arranged on different sides of the pressure relief component 6 in the thickness direction X of the first wall portion, for example, the first groove 61 is arranged on the first surface 64, and the second groove 62 is arranged on the second surface 65.

[0207] In this embodiment, the projection of the second groove 62 along the thickness direction X of the first wall portion does not overlap with the projection of the first groove 61 along the thickness direction X of the first wall portion, which can reduce the mutual influence between the first groove 61 and the second groove 62 during the processing process and reduce the risk of the first groove 61 and the second groove 62 being connected to each other during the processing.

[0208] In some embodiments, please continue to refer to Figures 5 to 7. Along the width direction Z of the second groove, the second groove 62 is spaced apart from the first groove 61. The width direction Z of the second groove is perpendicular to the thickness direction X of the first wall portion.

[0209] The second groove 62 is spaced apart from the first groove 61 along the width direction Z of the second groove. That is, the projection of the second groove 62 along the thickness direction X of the first wall portion is spaced apart from the projection of the first groove 61 along the thickness direction X of the first wall portion by a certain distance in the width direction Z of the second groove. In this embodiment, the second groove 62 and the first groove 61 can be located on the same side of the pressure relief component 6 in the thickness direction X of the first wall portion, or can be located on opposite sides of the pressure relief component 6 in the thickness direction X of the first wall portion. It will be understood that the projection of the second groove 62 along the thickness direction X of the first wall portion is spaced apart from the projection of the first groove 61 along the thickness direction X of the first wall portion along the width direction Z of the second groove.

[0210] As an example, in the embodiment shown in FIG6 , the housing 1 includes a first wall portion 13, a second wall portion 14, and a third wall portion 15. Along the width direction Z of the second groove, the second wall portion 14 and the third wall portion 15 are arranged opposite each other. The first wall portion 13 connects the second wall portion 14 and the third wall portion 15. The first wall portion 13 serves as the pressure relief component 6. The first wall portion 13 is provided with two second grooves 62. Along the width direction Z of the second groove, one second groove 62 is located between the first groove 61 and the second wall portion 14, and the other second groove 62 is located between the first groove 61 and the third wall portion 15.

[0211] In this embodiment, the second groove 62 and the first groove 61 are spaced apart along the width direction Z of the second groove, so that the projection of the second groove 62 along the thickness direction X of the first wall portion and the projection of the first groove 61 along the thickness direction X of the first wall portion do not overlap. On the one hand, the mutual influence between the first groove 61 and the second groove 62 during the processing can be reduced. On the other hand, the residual stress influence between the pressure relief component 6 in the area where the first groove 61 is set and the pressure relief component 6 in the area where the second groove 62 is set can be reduced, and the risk of cracks generated by the pressure relief component 6 cracking along the first groove 61 spreading to the second groove 62, thereby causing the pressure relief component 6 to crack along the second groove 62, can be reduced.

[0212] In some embodiments, referring to FIG. 5 , along the thickness direction X of the first wall portion, two ends of the projection of the second groove 62 along the extension direction respectively extend beyond two ends of the projection of the first groove 61 .

[0213] Along the thickness direction X of the first wall portion, the projection of the second groove 62 has two opposite ends in the extension direction, namely, a first end 623 and a second end 624. The two ends of the projection of the second groove 62 along the extension direction extend beyond the two ends of the projection of the first groove 61, that is, the two ends of the projection of the first groove 61 are located between the first end 623 and the second end 624 along the extension direction of the projection of the second groove 62. The extension direction of the projection of the second groove 62 along the thickness direction X of the first wall portion is parallel to the second groove extension direction Y. Along the second groove extension direction Y, the length of the second groove 62 is greater than the length of the first groove 61 (the maximum span of the first groove 61 along the second groove extension direction Y).

[0214] In this embodiment, the two ends of the projection of the second groove 62 along the thickness direction X of the first wall portion along the extension direction respectively extend beyond the two ends of the projection of the first groove 61 along the thickness direction X of the first wall portion, so that the second groove 62 is longer, thereby enhancing the auxiliary flipping effect of the second groove 62 on the predetermined pressure relief area 63. In addition, this structure can also improve the separation effect of the second groove 62 on the surface of the battery cell 10 in the width direction Z of the second groove (the outer surface of the second wall portion 14 or the outer surface of the third wall portion 15) and the first groove 61, improve the absorption effect of the second groove 62 on the excess material extruded during the molding of the first groove 61, improve the flatness of the surface of the battery cell 10 in the width direction Z of the second groove, and improve the blocking effect of the second groove 62 on the deformation energy of the battery cell 10 when the battery cell 10 is subjected to internal and external impact forces, thereby reducing the influence of the expansion of the battery cell 10 on the pressure relief component 6.

[0215] In some embodiments, referring to FIG. 7 , the minimum residual thickness of the first groove 61 is D1 , and the minimum residual thickness of the second groove 62 is D2 , satisfying: D1 < D2 .

[0216] The minimum residual thickness of the first groove 61 is the minimum thickness of the remaining portion after the pressure relief component 6 is provided with the first groove 61, and the remaining portion may be the bottom wall of the first groove 61. The thickness of the bottom wall of the first groove 61 may be uniform or uneven. If the thickness of the bottom wall of the first groove 61 is uneven, the thickness of the thinnest position of the bottom wall of the first groove 61 is the minimum residual thickness of the first groove 61. In an embodiment where the first groove 61 includes multiple groove segments, the minimum residual thicknesses of all groove segments may be equal, and the minimum residual thickness of any groove segment is the minimum residual thickness of the first groove 61; if the minimum residual thicknesses of at least two groove segments are unequal, the minimum residual thickness of the groove segment with the smallest minimum residual thickness is the minimum residual thickness of the first groove 61. The minimum residual thickness of a groove segment is the minimum thickness of the remaining portion after the pressure relief component 6 is provided with the groove segment, and the remaining portion may be the bottom wall of the groove segment.

[0217] The minimum residual thickness of the second groove 62 is the minimum thickness of the remaining portion of the pressure relief component 6 after the second groove 62 is provided. The remaining portion may be the bottom wall of the second groove 62. The thickness of the bottom wall of the second groove 62 may be uniform or uneven. If the thickness of the bottom wall of the second groove 62 is uneven, the thickness of the thinnest portion of the bottom wall of the second groove 62 is the minimum residual thickness of the second groove 62.

[0218] In this embodiment, D1<D2 makes the strength of the area where the first groove 61 of the pressure relief component 6 is set smaller than the strength of the area where the second groove 62 of the pressure relief component 6 is set, so that the pressure relief component 6 can preferentially break along the first groove 61 to achieve rapid opening of the predetermined pressure relief area 63.

[0219] In some embodiments, referring to FIG. 7 , along the thickness direction X of the first wall portion, the maximum groove depth of the first groove 61 is H1 , and the maximum groove depth of the second groove 62 is H2 , satisfying: H2 < H1 .

[0220] The maximum distance between the notch of the first groove 61 and the groove bottom surface 614 of the first groove along the thickness direction X of the first wall portion is the maximum groove depth of the first groove 61; the maximum distance between the notch of the second groove 62 and the groove bottom surface 625 of the second groove along the thickness direction X of the first wall portion is the maximum groove depth of the second groove 62.

[0221] As an example, the first surface 64 is parallel to the second surface 65 , the distance between the first surface 64 and the second surface 65 is D, the thickness of the pressure relief component 6 is D, and D= D1 + H1 = D2 + H2 .

[0222] In this embodiment, H2

[0223] In some embodiments, along the thickness direction X of the first wall portion, the maximum groove depth of the first groove 61 is H1, the thickness of the pressure relief component 6 is D, and 0.16≤H1 / D<1.

[0224] H1 / D can take any point value among 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.

[0225] It is understandable that if the pressure relief component 6 and the first wall portion 13 are integrally formed, the first wall portion 13 can serve as the pressure relief component 6 , and the thickness of the pressure relief component 6 is the same as the thickness of the first wall portion 13 .

[0226] In this embodiment, 0.16≤H1 / D<1, so that the maximum depth of the first groove 61 accounts for a small proportion of the thickness of the pressure relief component 6, and the bursting pressure of the battery cell 10 is not too high, which is conducive to improving the timeliness of the pressure relief of the battery cell 10.

[0227] In some embodiments, 0.4 mm ≤ H1 ≤ 2 mm, and 0.8 mm ≤ D ≤ 2.5 mm.

[0228] ​H1 can take any point value among 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, etc., or any range value between any two of them.

[0229] D 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.

[0230] In this embodiment, 0.4 mm ≤ H1 ≤ 2 mm, and 0.8 mm ≤ D ≤ 2.5 mm, keeping the maximum depth of the first groove and the thickness of the pressure relief component 6 within a reasonable range, resulting in better economic efficiency. In an embodiment where the first wall portion 13 serves as the pressure relief component 6, the thickness of the first wall portion 13 is 0.8 mm to 2.5 mm. The thickness of the first wall portion 13 is greater than or equal to 0.8 mm, ensuring sufficient strength. The thickness of the first wall portion 13 is less than or equal to 2 mm, ensuring that the thickness of the first wall portion 13 is not excessive. Given a given volume of the housing 1, the internal space of the housing 1 can be increased to create more space for the electrode assembly 2. While maintaining the thickness of the first wall portion 13 within the range of 0.8 mm to 2.5 mm, the maximum depth of the first groove 61 is controlled within the range of 0.4 mm to 2 mm, ensuring that the maximum depth of the first groove 61 is more closely aligned with the thickness of the pressure relief component 6, thereby ensuring that the pressure relief component 6 has excellent pressure relief capabilities.

[0231] In some embodiments, along the thickness direction X of the first wall portion, the pressure relief component 6 has a first surface 64 and a second surface 65 opposite to each other. The first groove 61 is provided on the first surface 64 , and the second groove 62 is provided on the second surface 65 .

[0232] The first surface 64 and the second surface 65 are two opposing surfaces of the pressure relief component 6 along the thickness direction X of the first wall portion. The first groove 61 is provided on the first surface 64, that is, the first groove 61 is recessed from the first surface 64 toward the second surface 65; the second groove 62 is provided on the second surface 65, that is, the second groove 62 is recessed from the second surface 65 toward the first surface 64. One of the first surface 64 and the second surface 65 can be the outer surface of the pressure relief component 6, and the other can be the inner surface of the pressure relief component 6. The outer surface of the pressure relief component 6 faces the outside of the battery cell 10, and the inner surface of the pressure relief component 6 faces the inside of the battery cell 10. The first surface 64 and the second surface 65 can be planes. The first surface 64 and the second surface 65 can be parallel to each other or at a non-zero angle. As an example, in the embodiment shown in Figure 7, the first surface 64 is parallel to the second surface 65.

[0233] As an example, the minimum distance between the groove bottom surface 614 of the first groove and the second surface 65 along the thickness direction X of the first wall portion is equal to the minimum residual thickness of the first groove 61, and the minimum distance between the groove bottom surface 625 of the second groove and the first surface 64 along the thickness direction X of the first wall portion is equal to the minimum residual thickness of the second groove 62. The maximum groove depth of the first groove 61 is equal to the maximum distance between the first surface 64 and the groove bottom surface 614 of the first groove along the thickness direction X of the first wall portion, and the maximum groove depth of the second groove 62 is equal to the maximum distance between the second surface 65 and the groove bottom surface 625 of the second groove along the thickness direction X of the first wall portion.

[0234] In this embodiment, the first groove 61 and the second groove 62 are respectively arranged on the first surface 64 and the second surface 65, and the first groove 61 and the second groove 62 are respectively located on both sides of the pressure relief component 6 along the thickness direction X of the first wall portion, so that the first groove 61 and the second groove 62 can be processed on both sides of the pressure relief component 6, which is beneficial to reduce the mutual influence of the first groove 61 and the second groove 62 during the processing.

[0235] In some embodiments, referring to FIG. 7 , along the width direction Z of the second groove, the projection of the first groove 61 and the projection of the second groove 62 at least partially overlap, and the width direction Z of the second groove is perpendicular to the thickness direction X of the first wall portion.

[0236] The projection of the first groove 61 along the width direction Z of the second groove and the projection of the second groove 62 along the width direction Z of the second groove may partially overlap or completely overlap. If the two completely overlap, a first protrusion may be provided at a position on the first surface 64 corresponding to the second groove 62, so that the second groove 62 does not penetrate the pressure relief component 6 along the thickness direction X of the first wall. A second protrusion may be provided at a position on the second surface 65 opposite the first groove 61, so that the first groove 61 does not penetrate the pressure relief component 6 along the thickness direction X of the first wall.

[0237] It can be understood that the projections of the first groove 61 and the second groove 62 along the width direction Z of the second groove have an overlapping area. It can also be understood that the projections of the groove wall surface (groove bottom surface and groove side surface) of the first groove 61 and the groove wall surface (groove bottom surface and groove side surface) of the second groove 62 along the width direction Z of the second groove at least partially overlap.

[0238] It should be noted that if the bottom surface 614 of the first groove and the bottom surface 625 of the second groove are exactly flush, the projections of the bottom surface 614 of the first groove and the bottom surface 625 of the second groove along the width direction Z of the second groove overlap, and the overlapping area is a line. In this case, the projection of the first groove 61 and the projection of the second groove 62 also partially overlap.

[0239] In this embodiment, the projections of the first groove 61 and the second groove 62 along the width direction Z of the second groove at least partially overlap, so that the projections of the first groove 61 and the second groove 62 in the width direction Z of the second groove have overlapping areas. This can, on the one hand, improve the absorption effect of the second groove 62 on the residual material squeezed out during molding of the first groove 61, and reduce the risk of the extruded residual material of the first groove 61 diffusing to the surface close to the shell 1 along the width direction Z of the second groove, thereby causing the surface to be uneven. On the other hand, it can improve the absorption effect of the second groove 62 on the deformation energy of the battery cell 10 when the battery cell 10 is subjected to internal and external forces and deformed along the width direction Z of the second groove, and reduce the influence of the expansion and deformation of the battery cell 10 along the width direction Z of the second groove on the pressure relief component 6.

[0240] In some embodiments, referring to FIG. 7 , along the thickness direction X of the first wall portion, the bottom surface 625 of the second groove is closer to the first surface 64 than the bottom surface 614 of the first groove.

[0241] It can be understood that, along the thickness direction X of the first wall portion, the minimum distance between the groove bottom surface 625 of the second groove and the first surface 64 is smaller than the minimum distance between the groove bottom surface 614 of the first groove and the first surface 64 .

[0242] The bottom surface 614 of the first groove can be a flat surface or an arcuate surface; the bottom surface 625 of the second groove can be a flat surface or an arcuate surface. As an example, in the embodiment shown in FIG7 , the bottom surface 614 of the first groove and the bottom surface 625 of the second groove are both flat surfaces and parallel to the first surface 64 and the second surface 65.

[0243] In this embodiment, the bottom surface 625 of the second groove is closer to the first surface 64 than the bottom surface 614 of the first groove. This structure is conducive to achieving more overlapping areas between the projections of the second groove 62 and the first groove 61 in the width direction Z of the second groove, further improving the absorption effect of the second groove 62 on the residual material squeezed out of the first groove 61 during molding, and further improving the absorption effect of the second groove 62 on the deformation energy of the battery cell 10 when the battery cell 10 is subjected to internal and external forces and deformed along the width direction Z of the second groove.

[0244] In some embodiments, along the thickness direction X of the first wall portion, the maximum groove depth of the second groove 62 is H2, and the minimum residual thickness of the first groove 61 is D1, satisfying: D1<H2.

[0245] As an example, the first surface 64 is parallel to the second surface 65, the notch of the second groove 62 is located on the second surface 65, and along the thickness direction X of the first wall portion, the portion between the groove bottom surface 614 of the first groove and the second surface 65 is the residual portion of the first groove 61. The minimum thickness of this residual portion is the minimum residual thickness of the first groove 61, and the maximum distance between the groove bottom surface 625 of the second groove and the second surface 65 is the maximum groove depth of the second groove 62. The second surface 65 is the reference surface for measuring the maximum groove depth of the second groove 62 and the minimum residual thickness of the first groove 61.

[0246] In this embodiment, D1<H2. This structure is conducive to achieving a larger overlapping area between the projections of the second groove 62 and the first groove 61 in the width direction Z of the second groove, further improving the absorption effect of the second groove 62 on the residual material squeezed out of the first groove 61 during molding, and further improving the absorption effect of the second groove 62 on the deformation energy of the battery cell 10 when the battery cell 10 is subjected to internal and external forces and deformed along the width direction Z of the second groove.

[0247] In some embodiments, please refer to Figures 8-11. Figure 8 is an assembly diagram of a battery cell 10 provided in other embodiments of the present application; Figure 9 is a partial view of the housing 1 shown in Figure 8; Figure 10 is a CC cross-sectional view of the housing 1 shown in Figure 9; and Figure 11 is a partial enlarged view of point D in Figure 10. The first groove 61 comprises a plurality of grooves arranged sequentially from the first surface 64 to the second surface 65. Along the thickness direction X of the first wall portion, in two adjacent grooves, the primary groove farther from the first surface 64 is arranged at the bottom surface of the primary groove closer to the first surface 64. The primary groove of the multi-stage groove arranged on the first surface 64 is the first groove 615. Along the width direction Z of the second groove, the projection of the second groove 62 at least partially overlaps with the projection of the first groove 615. The width direction Z of the second groove is perpendicular to the thickness direction X of the first wall portion.

[0248] The first groove 61 can be a two-stage groove, a three-stage groove, a four-stage groove, a five-stage groove, or the like. It is understood that the first groove 61 is a stepped groove. The width of each stage of the groove gradually decreases from the first surface 64 to the second surface 65. The volume of the first groove 61 is equal to the sum of the volumes of each stage of the groove. As shown in FIG11 , taking the first groove 61 as a two-stage groove as an example, the two stages are a first-stage groove 615 and a second-stage groove. During machining, the first-stage groove 615 with a larger width can be machined first on the first surface 64, and then the second-stage groove with a smaller width can be machined on the bottom surface of the first-stage groove 615.

[0249] The first-stage groove 615 is a primary groove disposed on the first surface 64 within the first groove 61. In embodiments where the first groove 61 comprises multiple groove segments, it is understood that each groove segment is a multi-stage groove, and all the primary groove segments disposed on the first surface 64 constitute the first-stage groove 615. Within the multi-stage grooves of the first groove 61, the groove bottom surface of the primary groove furthest from the first surface 64 is the groove bottom surface 614 of the first groove, the minimum residual thickness of the primary groove furthest from the first surface 64 is the minimum residual thickness of the first groove 61, and the maximum distance between the groove bottom surface of the primary groove furthest from the first surface 64 and the first surface 64 is equal to the maximum groove depth of the first groove 61. When calculating the volume of the first groove 61, the volume of each groove segment can be calculated first. Since each groove segment has a multi-stage groove structure, the volume of each groove stage within each groove segment can be calculated separately when calculating the volume of each groove segment. For each level of the slot in each slot section, the length and cross-sectional area of ​​each level of the slot in each slot section can be measured first, and the length and cross-sectional area can be multiplied to calculate the volume of each level of the slot in each slot section. Taking the cross-section of the first-level slot in the slot section as an example, the pressure relief component 6 can be cut along the direction perpendicular to the extension of the slot section, and the groove depth and groove width of the first-level slot in the slot section can be measured on the upper side of the cross-section of the pressure relief component 6 (the cross-section is as close as possible to the midpoint of the slot section in the extension direction), and then the groove depth and groove width can be multiplied to calculate the cross-sectional area of ​​the first-level slot in the slot section. It should be noted that if the first-level slot in the slot section has rounded corners or chamfers at both ends in the extension direction, the calculated volume calculated by multiplying the length and cross-sectional area of ​​the first-level slot can be regarded as the actual volume of the first-level slot.

[0250] The projection of the second groove 62 along the width direction Z of the second groove may partially overlap or completely overlap with the projection of the first-stage groove 615 along the width direction Z of the second groove. If the two completely overlap, a first protrusion may be provided at a position on the first surface 64 corresponding to the second groove 62, so that the second groove 62 does not penetrate the pressure relief component 6 along the thickness direction X of the first wall. A second protrusion may be provided at a position on the second surface 65 opposite the first-stage groove 615, so that the first groove 61 does not penetrate the pressure relief component 6 along the thickness direction X of the first wall.

[0251] It can be understood that the projections of the second groove 62 and the first-stage groove 615 along the width direction Z of the second groove have an overlapping area. It can also be understood that the projections of the groove wall surface (groove bottom surface and groove side surface) of the second groove 62 and the groove wall surface (groove bottom surface and groove side surface) of the first-stage groove 615 along the width direction Z of the second groove at least partially overlap.

[0252] In this embodiment, by setting the first groove 61 as a multi-level groove arranged along the thickness direction X of the first wall portion, when forming the first groove 61, each level of groove can be processed one by one along the direction from the first surface 64 to the second surface 65, thereby reducing the forming depth of each level of groove, reducing the forming force exerted on the pressure relief component 6 when forming the first groove 61, and reducing the risk of the pressure relief component 6 being damaged when forming the first groove 61. Since the projection of the first-level groove 615 of the first groove 61 along the width direction Z of the second groove overlaps at least partially with the projection of the second groove 62 along the width direction Z of the second groove, the projection of the second groove 62 in the width direction can not only cover a part of the first groove 61, but also cover the other levels of grooves in the first groove 61 except the first-level groove 615. On the one hand, the absorption effect of the second groove 62 on the residual material squeezed out of the first groove 61 during the multi-level groove forming process can be further improved. On the other hand, the absorption effect of the second groove 62 on the deformation energy of the battery cell 10 when the battery cell 10 is subjected to internal and external impact forces and deformed can be further improved, thereby reducing the influence of the expansion and deformation of the battery cell 10 along the width direction Z of the second groove on the pressure relief component 6.

[0253] In some embodiments, referring to FIG. 11 , along the thickness direction X of the first wall portion, the bottom surface 625 of the second groove is closer to the first surface 64 than the bottom surface of the first-stage groove 615 .

[0254] It can be understood that, along the thickness direction X of the first wall portion, the minimum distance between the groove bottom surface 625 of the second groove and the first surface 64 is smaller than the minimum distance between the groove bottom surface 615 of the first-level groove and the first surface 64 .

[0255] The bottom surface 625 of the second groove can be a flat surface or an arcuate surface; the bottom surface of the first-stage groove 615 can be a flat surface or an arcuate surface. As an example, in the embodiment shown in FIG11 , the bottom surface of the first-stage groove 615 and the bottom surface 625 of the second groove are both flat surfaces and parallel to the first surface 64 and the second surface 65.

[0256] In this embodiment, the projection of the second groove 62 in the width direction can cover the other levels of grooves in the first groove 61 except the first-level groove 615, and can cover more parts of the first-level groove 615. On the one hand, it can improve the absorption effect of the second groove 62 on the residual material squeezed out of the first groove 61 when the multi-level groove is formed. On the other hand, it can improve the absorption effect of the second groove 62 on the deformation energy of the battery cell 10 when the battery cell 10 is subjected to internal and external impact forces and deformed, and reduce the influence of the expansion deformation of the battery cell 10 along the width direction Z of the second groove on the pressure relief component 6.

[0257] In some other embodiments, along the thickness direction X of the first wall portion, the groove bottom surface 625 of the second groove is flush with the groove bottom surface of the first-stage groove 615 .

[0258] As an example, the groove bottom surface 625 of the second groove and the groove bottom surface of the first-stage groove 615 are both flat and coplanar.

[0259] In this embodiment, the projection of the second groove 62 in the width direction can cover the other levels of grooves in the first groove 61 except the first-level groove 615. On the one hand, it can improve the absorption effect of the second groove 62 on the residual material squeezed out of the first groove 61 during the processing of the multi-level groove. On the other hand, it can further improve the absorption effect of the second groove 62 on the deformation energy of the battery cell 10 when the battery cell 10 is subjected to internal and external impact forces and deformed, thereby reducing the influence of the expansion and deformation of the battery cell 10 along the width direction Z of the second groove on the pressure relief component 6.

[0260] In some embodiments, referring to Figures 12 and 13 , Figure 12 is a partial cross-sectional view of the housing 1 provided in some embodiments of the present application; Figure 13 is a partial enlarged view of point E in Figure 12 . Along the thickness direction X of the first wall portion, the pressure relief component 6 has opposing first and second surfaces 64 and 65 , and both the first and second grooves 61 and 62 are recessed from the second surface 65 toward the first surface 64 .

[0261] It is understandable that the first groove 61 and the second groove 62 are both provided on the second surface 65. The second surface 65 can be the outer surface of the external component or the inner surface of the external component.

[0262] In this embodiment, the first groove 61 and the second groove 62 are arranged on the same side of the pressure relief component 6 in the thickness direction X of the first wall portion, which makes it easier to process the first groove 61 and the second groove 62 on the pressure relief component 6. The first groove 61 and the second groove 62 can be processed without flipping the pressure relief component 6, which is beneficial to optimizing the production rhythm of the battery cell 10.

[0263] In some embodiments, referring again to FIG. 13 , the first groove 61 includes a plurality of grooves sequentially arranged along the direction from the second surface 65 to the first surface 64. Along the thickness direction X of the first wall portion, in two adjacent grooves, the primary groove farther from the second surface 65 is arranged at the groove bottom surface of the primary groove closer to the second surface 65. Among the plurality of grooves, the primary groove arranged on the second surface 65 is the first groove 615. Along the thickness direction X of the first wall portion, the groove bottom surface of the first groove 615 is closer to the second surface 65 than the groove bottom surface 625 of the second groove.

[0264] The first-stage groove 615 is a first-stage groove disposed on the second surface 65 within the first groove 61. Among the multi-stage grooves of the first groove 61, the groove bottom surface of the first-stage groove farthest from the second surface 65 is the groove bottom surface 614 of the first groove. The minimum residual thickness of the first-stage groove farthest from the second surface 65 is the minimum residual thickness of the first groove 61. The maximum distance between the groove bottom surface of the first-stage groove farthest from the second surface 65 and the second surface 65 is equal to the maximum groove depth of the first groove 61. Along the thickness direction X of the first wall portion, the minimum distance between the groove bottom surface 625 of the second groove and the first surface 64 is equal to the minimum residual thickness of the second groove 62. The minimum distance between the groove bottom surface of the first-stage groove farthest from the second surface 65 and the first surface 64 is equal to the minimum residual thickness of the first groove 61.

[0265] It can be understood that, along the thickness direction X of the first wall portion, the minimum distance between the bottom surface of the first-stage groove 615 and the second surface 65 is smaller than the minimum distance between the bottom surface 625 of the second groove and the second surface 65 .

[0266] The bottom surface 625 of the second groove can be a flat surface or an arcuate surface; the bottom surface of the first-stage groove 615 can be a flat surface or an arcuate surface. As an example, in the embodiment shown in FIG13 , the bottom surface of the first-stage groove 615 and the bottom surface 625 of the second groove are both flat surfaces and parallel to the first surface 64 and the second surface 65.

[0267] In this embodiment, by configuring the first groove 61 as a multi-stage groove arranged along the thickness direction X of the first wall portion, each stage of grooves can be machined one by one along the direction from the second surface 65 to the first surface 64 during the formation of the first groove 61. This reduces the forming depth of each stage of grooves, reduces the forming force applied to the pressure relief component 6 during the formation of the first groove 61, and reduces the risk of damage to the pressure relief component 6 during the formation of the first groove 61. Because the bottom surface of the first stage groove 615 is closer to the second surface 65 than the bottom surface 625 of the second groove, the projection of the second groove 62 along the width direction at least covers the first stage groove 615 of the first groove 61, resulting in a deeper depth of the second groove 62. This allows the second groove 62 to effectively absorb excess material extruded during the formation of the first stage groove 615. Furthermore, the second groove 62 effectively absorbs deformation energy of the battery cell 10 when the battery cell 10 is subjected to internal and external impact forces and deforms.

[0268] In some embodiments, referring to FIG. 13 , along the thickness direction X of the first wall portion, the maximum groove depth of the second groove 62 is H2, and the maximum groove depth of the first-level groove 615 is H3, satisfying: H3<H2.

[0269] As an example, the maximum distance between the bottom surface 625 of the second groove and the second surface 65 along the thickness direction X of the first wall portion is the maximum groove depth of the second groove 62, and the maximum distance between the bottom surface of the first-stage groove 615 and the second surface 65 along the thickness direction X of the first wall portion is the maximum groove depth of the first-stage groove 615. The maximum groove depth of the second groove 62 is greater than the maximum groove depth of the first-stage groove 615, so that the bottom surface of the first-stage groove 615 is closer to the second surface 65 than the bottom surface 625 of the second groove.

[0270] In this embodiment, H3 is less than H2, so that the second groove 62 has a deeper depth, so that the second groove 62 can effectively absorb the excess material squeezed out when the first-level groove 615 is formed, and the second groove 62 can effectively absorb the deformation energy of the battery cell 10 when the battery cell 10 is subjected to internal and external impact forces and deformed.

[0271] 6 , 7 , and 10 - 13 , the first surface 64 is the surface of the pressure relief component 6 facing the outside of the battery cell 10 , and the second surface 65 is the surface of the pressure relief component 6 facing the inside of the battery cell 10 .

[0272] The first surface 64 is the outer surface of the pressure relief component 6 , and the second surface 65 is the inner surface of the pressure relief component 6 .

[0273] The first surface 64 is the surface of the pressure relief component 6 facing the exterior of the battery cell 10. When the first groove 61 is provided on the first surface 64, the first groove 61 is provided on the exterior of the pressure relief component 6, facilitating the formation of the first groove 61 on the exterior of the battery cell 10. This reduces the difficulty of forming the first groove 61 and improves the production efficiency of the battery cell 10. The second surface 65 is the surface of the pressure relief component 6 facing the interior of the battery cell 10. When the second groove 62 is provided on the second surface 65, the second groove 62 is provided on the interior of the pressure relief component 6. This prevents the two groove side surfaces (the first groove side surface 621 and the second groove side surface 622) of the second groove 62 from abutting against each other during the outward flipping and opening of the predetermined pressure relief area 63, thereby increasing the opening area of ​​the predetermined pressure relief area 63. Furthermore, the second groove 62 is not exposed to the exterior of the battery cell 10, reducing the risk of oxidation and corrosion of the pressure relief component 6 in the second groove 62 region. In addition, the second surface 65 is the surface of the pressure relief component 6 facing the interior of the battery cell 10. When the first groove 61 is arranged on the second surface 65, the first groove 61 is arranged on the inner side of the pressure relief component 6, which can reduce the risk of the pressure relief component 6 being oxidized and corroded in the first groove 61 area.

[0274] In other embodiments, the first surface 64 may be the surface of the pressure relief component 6 facing the interior of the battery cell 10 , and the second surface 65 may be the surface of the pressure relief component 6 facing the exterior of the battery cell 10 .

[0275] In some embodiments, please refer to Figures 14 and 15. Figure 14 is a partial view of the housing 1 (first groove 61 is an arc-shaped groove) provided in some embodiments of the present application; Figure 15 is a FF cross-sectional view of the housing 1 shown in Figure 14. Along the thickness direction X of the first wall portion, the projection of the first groove 61, the projection of the extension line 61a of the first groove, and the projection of the second groove 62 together enclose a predetermined pressure relief area 63.

[0276] The first groove 61 may include only one groove segment, and may be a groove extending along a non-linear trajectory, for example, a groove extending along an arc trajectory, a parabolic trajectory, etc. The first groove 61 may have extension lines at both ends, and along the thickness direction X of the first wall, the projections of the extension lines at both ends of the first groove 61 intersect with the projection of the second groove 62. Alternatively, the first groove 61 may have an extension line at only one end, and along the thickness direction X of the first wall, the projection of the extension line at one end of the first groove 61 intersects with the projection of the second groove 62, and the projections of the first groove 61 and the second groove 62 intersect at the projection of the other end of the first groove 61.

[0277] The first groove 61 may include multiple groove segments, which may form a U-shaped, H-shaped, V-shaped, Y-shaped, X-shaped, T-shaped, or other structures. The extension line 61a of the first groove may be one or more groove segments. For example, if the first groove 61 includes three groove segments, and the three groove segments form a U-shaped structure, then the two groove segments located at both ends of the first groove 61 may both have extension lines, and along the thickness direction X of the first wall, the projections of the extension lines of the two groove segments intersect with the projection of the second groove 62. Alternatively, only one groove segment may have an extension line, and along the thickness direction X of the first wall, the projection of the extension line of one groove segment intersects with the projection of the second groove 62, and the projection of the other groove segment intersects with the projection of the second groove 62.

[0278] Regardless of whether the first groove 61 includes only one groove segment or multiple groove segments, the extension line 61a of the first groove is the portion that continues to extend from the end of the groove segment along the extension direction of the groove segment located at the end of the first groove 61. It is understood that if the groove segment extends along an arc trajectory, the extension line 61a of the first groove also extends along the arc trajectory; if the groove segment extends along a straight trajectory, the extension line 61a of the first groove also extends along the straight trajectory.

[0279] As an example, in the embodiment shown in Figures 14 and 15, the first groove 61 is an arcuate groove. The first groove 61 is provided on the first surface 64, and the second groove 62 is provided on the second surface 65. Along the width direction Z of the second groove, the second groove 62 is spaced apart from the first groove 61. Along the thickness direction X of the first wall portion, the projection of the second groove 62 extends beyond the two ends of the projection of the first groove 61. The edge of the measurement surface of the predetermined pressure relief zone 63 is formed by connecting the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side closest to the predetermined pressure relief zone 63) on the first surface 64, the inner edge of the notch of the first groove 61 (the edge of the notch of the first groove 61 on the side closest to the predetermined pressure relief zone 63) on the first surface 64, and the projection of the extended lines of the two ends of the inner edge of the notch of the first groove 61 on the first surface 64. The area of ​​the measurement surface of the predetermined pressure relief zone 63 is the area of ​​the predetermined pressure relief zone 63. When measuring the area of ​​the predetermined pressure relief zone 63, a first straight line can be drawn on the first surface 64 so that the projection of the inner edge of the notch of the second groove 62 on the first surface 64 is located within the first straight line. Then, an extension line of the inner edge of the notch of the first groove 61 is drawn on the first surface 64 along the extension direction of the inner edge and intersects with the first straight line, thereby defining a measuring surface. The edge of the measuring surface is composed of an arc and a straight line.

[0280] In this embodiment, the projection of the first groove 61 along the thickness direction X of the first wall portion, the projection of the extension line 61a of the first groove along the thickness direction X of the first wall portion, and the projection of the second groove 62 along the thickness direction X of the first wall portion jointly enclose a predetermined pressure relief area 63. This structure ensures that the projection of the second groove 62 along the thickness direction X of the first wall portion and the projection of the first groove 61 along the thickness direction X of the first wall portion do not form a closed structure, thereby reducing the mutual influence between the first groove 61 and the second groove 62 during the processing process, and reducing the risk of the predetermined pressure relief area 63 falling off and splashing during pressure relief.

[0281] In some embodiments, please refer to Figure 16, which is a partial view of the housing 1 (first groove 61 is an arc-shaped groove) provided in other embodiments of the present application. Along the thickness direction X of the first wall portion, the projection of the first groove 61, the projection of the second groove 62, and the projection of the extension line 62a of the second groove together enclose a predetermined pressure relief area 63.

[0282] The first groove 61 may include only one groove segment. The first groove 61 may be a groove extending along a non-linear trajectory. For example, the first groove 61 is a groove extending along an arc trajectory, a parabolic trajectory, etc. The first groove 61 may include multiple groove segments, and the multiple groove segments may form a U-shaped, H-shaped, V-shaped, Y-shaped, X-shaped, T-shaped, etc. structure.

[0283] The extension line 62a of the second groove is the portion that continues to extend from the end of the second groove 62 along the extension direction Y of the second groove. If the second groove 62 extends along an arcuate trajectory, the extension line 62a of the second groove also extends along the arcuate trajectory; if the second groove 62 extends along a straight trajectory, the extension line 62a of the second groove also extends along the straight trajectory. The second groove 62 may have an extension line at both ends, and the projections of the extension lines at both ends of the second groove 62 intersect with the projection of the first groove 61 along the thickness direction X of the first wall. Alternatively, the second groove 62 may have an extension line at only one end, and the projection of the extension line of one end of the second groove 62 intersects with the projection of the first groove 61 along the thickness direction X of the first wall, and the projection of the second groove 62 intersects with the projection of the first groove 61 at the projection of the other end of the second groove 62.

[0284] As an example, in the embodiment shown in FIG16 , the first groove 61 is an arcuate groove. The first groove 61 is provided on a first surface 64 (not shown in FIG16 ), and the second groove 62 is provided on a second surface 65 (not shown in FIG16 ). The second groove 62 is located within the area enclosed by the line connecting the two ends of the first groove 61 and the first groove 61. The edge of the measurement surface of the predetermined pressure relief zone 63 is formed by connecting the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side closest to the predetermined pressure relief zone 63) on the first surface 64, the projection of the extended line of the inner edge of the notch of the second groove 62 on the first surface 64, and the projection of the inner edge of the notch of the first groove 61 (the edge of the notch of the first groove 61 on the side closest to the predetermined pressure relief zone 63) on the first surface 64. The area of ​​the measurement surface of the predetermined pressure relief zone 63 is the area of ​​the predetermined pressure relief zone 63. When measuring the area of ​​the predetermined pressure relief zone 63, a first straight line can be drawn on the first surface 64 so that the projection of the inner edge of the notch of the second groove 62 on the first surface 64 is located within the first straight line, and the two ends of the first straight line respectively extend to the inner edge of the notch of the first groove 61, thereby defining a measuring surface, the edge of which is composed of an arc and a straight line.

[0285] In this embodiment, the projection of the first groove 61 along the thickness direction X of the first wall portion, the projection of the second groove 62 along the thickness direction X of the first wall portion, and the projection of the extension line 62a of the second groove along the thickness direction X of the first wall portion jointly enclose a predetermined pressure relief area 63. This structure ensures that the projection of the second groove 62 along the thickness direction X of the first wall portion and the projection of the first groove 61 along the thickness direction X of the first wall portion do not form a closed structure, thereby reducing the mutual influence between the first groove 61 and the second groove 62 during the processing process, and reducing the risk of the predetermined pressure relief area 63 falling off and splashing during pressure relief.

[0286] In some embodiments, please refer to Figure 17, which is a partial view of the housing 1 (first groove 61 is an arc-shaped groove) provided in some other embodiments of the present application. Along the thickness direction X of the first wall portion, the projection of the first groove 61, the projection of the extension line 61a of the first groove, the projection of the second groove 62, and the projection of the extension line 62a of the second groove together enclose a predetermined pressure relief area 63.

[0287] The first groove 61 may include only one groove segment, and the first groove 61 may be a groove extending along a non-linear trajectory, for example, a groove extending along an arc trajectory, a parabolic trajectory, etc. Both ends of the first groove 61 may have extension lines, and both ends of the second groove 62 may also have extension lines, and along the thickness direction X of the first wall portion, the projections of the extension lines at both ends of the first groove 61 intersect with the projections of the extension lines at both ends of the second groove 62 respectively; or only one end of the first groove 61 may have an extension line, and only one end of the second groove 62 may have an extension line, and along the thickness direction X of the first wall portion, the projection of the extension line of one end of the first groove 61 intersects with the projection of the extension line of one end of the second groove 62, and the projection of the other end of the first groove 61 is connected to the projection of the other end of the second groove 62.

[0288] The first groove 61 may include multiple groove segments, which may form a U-shaped, H-shaped, V-shaped, Y-shaped, X-shaped, T-shaped, or other structures. The extension line of one or more groove segments may be the extension line 61a of the first groove. For example, if the first groove 61 includes three groove segments, the three groove segments form a U-shaped structure. In the two groove segments located at both ends of the first groove 61, both groove segments may have extension lines, and along the thickness direction X of the first wall, the projections of the extension lines of the two groove segments intersect with the projections of the extension lines of the two ends of the second groove 62, respectively. Alternatively, only one groove segment may have an extension line, and along the thickness direction X of the first wall, the projection of the extension line of one groove segment intersects with the projection of the extension line 62a of the second groove, and the projection of the other groove segment intersects with the projection of the second groove 62.

[0289] Regardless of whether the first groove 61 includes only one groove segment or multiple groove segments, the extension line 61a of the first groove is the portion that continues to extend from the end of the groove segment along the extension direction of the groove segment located at the end of the first groove 61. The extension line 62a of the second groove is the portion that continues to extend from the end of the second groove 62 along the extension direction Y of the second groove.

[0290] As an example, in the embodiment shown in FIG17 , the first groove 61 is an arcuate groove. The first groove 61 is provided on a first surface 64 (not shown in FIG17 ), and the second groove 62 is provided on a second surface 65 (not shown in FIG17 ). Along the width direction Z of the second groove, the second groove 62 is spaced apart from the first groove 61. Along the thickness direction X of the first wall portion, the projection of the second groove 62 does not extend beyond the two ends of the projection of the first groove 61. The edge of the measuring surface of the predetermined pressure relief area 63 is formed by connecting the projection of the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side closest to the predetermined pressure relief area 63) on the first surface 64, the projection of the extended lines of the two ends of the inner edge of the notch of the second groove 62 on the first surface 64, the projection of the inner edge of the notch of the first groove 61 (the edge of the notch of the first groove 61 on the side closest to the predetermined pressure relief area 63) on the first surface 64, and the projection of the extended lines of the two ends of the inner edge of the notch of the first groove 61 on the first surface 64. The area of ​​the measurement surface of the predetermined pressure relief zone 63 is the area of ​​the predetermined pressure relief zone 63. When measuring the area of ​​the predetermined pressure relief zone 63, a first straight line can be drawn on the first surface 64 so that the projection of the inner edge of the notch of the second groove 62 on the first surface 64 lies within the first straight line. Then, an extension line of the inner edge of the notch of the first groove 61 is drawn on the first surface 64 along the extension direction of the inner edge and intersects the first straight line, thereby defining a measurement surface. The edge of the measurement surface is formed by an arc and a straight line.

[0291] In this embodiment, the projection of the first groove 61 along the thickness direction X of the first wall portion, the projection of the extension line of the first groove 61 along the thickness direction X of the first wall portion, the projection of the second groove 62 along the thickness direction X of the first wall portion, and the projection of the extension line of the second groove 62 along the thickness direction X of the first wall portion jointly enclose a predetermined pressure relief area 63. This structure ensures that the projection of the second groove 62 along the thickness direction X of the first wall portion and the projection of the first groove 61 along the thickness direction X of the first wall portion do not form a closed structure, thereby reducing the mutual influence between the first groove 61 and the second groove 62 during the processing process, and reducing the risk of the predetermined pressure relief area 63 falling off and splashing during pressure relief.

[0292] In some embodiments, please continue to refer to FIG. 14 to FIG. 17 , the first groove 61 extends along an arc trajectory.

[0293] The central angle of the first groove 61 may be less than 15°, 30°, 45°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300°, 330°, etc.

[0294] In the embodiments shown in FIG. 14 to FIG. 17 , the central angle of the first groove 61 is greater than 180° and less than 270°.

[0295] In this embodiment, the first groove 61 extends along an arc track. The first groove 61 is an arc-shaped groove. The first groove 61 of this structure only includes one groove segment, which simplifies the structure of the first groove 61.

[0296] In some embodiments, the second groove 62 extends along a straight line. The second groove 62 is a straight groove with a simple structure and is easy to process and form.

[0297] In some embodiments, please refer to Figures 18 and 19. Figure 18 is a partial view of the housing 1 (the first groove 61 is a V-shaped groove) provided in some embodiments of the present application; Figure 19 is a GG cross-sectional view of the housing 1 shown in Figure 18. The first groove 61 includes a first groove section 611 and a second groove section 612, and the first groove section 611 is connected to the second groove section 612. Along the thickness direction X of the first wall portion, the projection of the first groove section 611, the projection of the extension line of the first groove section 611, the projection of the second groove section 612, the projection of the extension line of the second groove section 612, and the projection of the second groove 62 together enclose a predetermined pressure relief area 63.

[0298] The first groove section 611 and the second groove section 612 are two groove sections in the first groove 61. The first groove section 611 and the second groove section 612 can be linear grooves extending along a straight trajectory, or non-linear grooves extending along a non-linear trajectory, such as an arcuate groove extending along an arcuate trajectory. If both the first groove section 611 and the second groove section 612 extend along a straight trajectory, the first groove section 611 and the second groove section 612 can be arranged at an acute angle, a right angle, or an obtuse angle. The first groove section 611 and the second groove section 612 can be connected end-to-end to form a V-shaped, L-shaped, or other structure. In such a structure, the first groove 61 and one second groove 62 can define a predetermined pressure relief zone 63. The first groove section 611 and the second groove section 612 can also be arranged crosswise to form an X-shaped structure. In such a structure, the first groove 61 and two second grooves 62 can define two predetermined pressure relief zones 63, or four predetermined pressure relief zones 63, respectively. The extension line of the first slot segment 611 is the portion that continues to extend from the end of the first slot segment 611 along the extension direction of the first slot segment 611. The extension line of the second slot segment 612 is the portion that continues to extend from the end of the second slot segment 612 along the extension direction of the second slot segment 612. The extension line of the first slot segment 611 and the extension line of the second slot segment 612 are both extension lines 61a of the first groove.

[0299] As an example, in the embodiments shown in Figures 18 and 19, the first groove section 611 is connected to the second groove section 612 to form a V-shaped structure, the first groove 61 is arranged on the first surface 64, and the second groove 62 is arranged on the second surface 65. Along the width direction Z of the second groove, the second groove 62 is spaced apart from the first groove 61, and along the thickness direction X of the first wall portion, the projection of the second groove 62 extends out of the two ends of the projection of the first groove 61 at both ends along the extension direction. The edge of the measuring surface of the predetermined pressure relief zone 63 is formed by the projection of the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side close to the predetermined pressure relief zone 63) on the first surface 64, the projection of the inner edge of the notch of the first groove section 611 (the edge of the notch of the first groove section 611 on the side close to the predetermined pressure relief zone 63) on the first surface 64, the projection of the extended line of the inner edge of the notch of the first groove section 611 on the first surface 64, the projection of the inner edge of the notch of the second groove section 612 (the edge of the notch of the second groove section 612 on the side close to the predetermined pressure relief zone 63) on the first surface 64, and the projection of the extended line of the inner edge of the notch of the second groove section 612 on the first surface 64. The area of ​​the measuring surface of the predetermined pressure relief zone 63 is the area of ​​the predetermined pressure relief zone 63, and the predetermined pressure relief zone 63 is a triangle. When measuring the area of ​​the predetermined pressure relief zone 63, a first straight line can be drawn on the first surface 64 so that the projection of the inner edge of the notch of the second groove 62 on the first surface 64 is located within the first straight line. Then, an extension line of the inner edge of the notch of the first groove section 611 is drawn on the first surface 64 along the extension direction of the inner edge and intersects with the first straight line. Then, an extension line of the inner edge of the notch of the second groove section 612 is drawn on the first surface 64 along the extension direction of the inner edge and intersects with the first straight line, thereby defining a triangular measuring surface. By measuring the base and height of the triangle and multiplying the base by the height, the area of ​​the predetermined pressure relief zone 63 can be calculated.

[0300] It should be noted that, in the embodiment where the first groove 61 is a multi-stage groove structure, both the first groove section 611 and the second groove section 612 are multi-stage groove structures.

[0301] In this embodiment, the first groove 61 has a simple structure, and the stress at the position where the first groove section 611 and the second groove section 612 are connected is more concentrated, weaker, and more likely to crack. Therefore, when the battery cell 10 thermally runs away, the pressure relief component 6 can quickly crack from the first groove section 611 and the second groove section 612 after cracking from the position where the first groove section 611 and the second groove section 612 are connected, so that the predetermined pressure relief area 63 is opened more quickly and the pressure is relieved in time.

[0302] In some embodiments, please refer to FIG. 20 , which is a partial view of a housing 1 (where the first groove 61 is a V-shaped groove) provided in other embodiments of the present application. The first groove 61 includes a first groove section 611 and a second groove section 612, which are connected to each other. Along the thickness direction X of the first wall portion, the projection of the first groove section 611, the projection of the second groove section 612, the projection of the second groove 62, and the projection of the extension line of the second groove 62 collectively enclose a predetermined pressure relief area 63.

[0303] As an example, in the embodiment shown in Figure 20, the first groove segment 611 is connected to the second groove segment 612 to form a V-shaped structure, the first groove 61 is arranged on the first surface 64 (not shown in Figure 20), and the second groove 62 is arranged on the second surface 65 (not shown in Figure 20), and the second groove 62 is located in the area enclosed by the line connecting one end of the first groove segment 611 and one end of the second groove segment 612 and the first groove 61. The edge of the measuring surface of the predetermined pressure relief zone 63 is formed by the projection of the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side close to the predetermined pressure relief zone 63) on the first surface 64, the projection of the extended line of the two ends of the inner edge of the notch of the second groove 62 on the first surface 64, the projection of the inner edge of the notch of the first groove section 611 (the edge of the notch of the first groove section 611 on the side close to the predetermined pressure relief zone 63) on the first surface 64, and the projection of the inner edge of the notch of the second groove section 612 (the edge of the notch of the second groove section 612 on the side close to the predetermined pressure relief zone 63) on the first surface 64. The area of ​​the measuring surface of the predetermined pressure relief zone 63 is the area of ​​the predetermined pressure relief zone 63, and the predetermined pressure relief zone 63 is a triangle. When measuring the area of ​​the predetermined pressure relief zone 63, a first straight line can be drawn on the first surface 64 so that the projection of the inner edge of the notch of the second groove 62 on the first surface 64 is located within the first straight line, and the two ends of the first straight line extend to the inner edge of the notch of the first groove section 611 and the inner edge of the notch of the second groove section 612, respectively, thereby defining a triangular measuring surface. By measuring the base and height of the triangle and multiplying the base by the height, the area of ​​the predetermined pressure relief zone 63 can be calculated.

[0304] In this embodiment, the first groove 61 has a simple structure, and the stress at the position where the first groove section 611 and the second groove section 612 are connected is more concentrated, weaker, and more likely to crack. Therefore, when the battery cell 10 thermally runs away, the pressure relief component 6 can quickly crack from the first groove section 611 and the second groove section 612 after cracking from the position where the first groove section 611 and the second groove section 612 are connected, so that the predetermined pressure relief area 63 is opened more quickly and the pressure is relieved in time.

[0305] In some embodiments, please refer to FIG. 21 , which is a partial view of a housing 1 (where the first groove 61 is a V-shaped groove) provided in yet other embodiments of the present application. The first groove 61 includes a first groove section 611 and a second groove section 612, with the first groove section 611 connected to the second groove section 612. Along the thickness direction X of the first wall portion, the projection of the first groove section 611, the projection of the extension of the first groove section 611, the projection of the second groove section 612, the projection of the extension of the second groove section 612, the projection of the second groove 62, and the projection of the extension line 62a of the second groove collectively enclose a predetermined pressure relief area 63.

[0306] As an example, in the embodiment shown in Figure 21, the first groove section 611 is connected to the second groove section 612 to form a V-shaped structure, the first groove 61 is arranged on the first surface 64 (not shown in Figure 21), and the second groove 62 is arranged on the second surface 65 (not shown in Figure 21). Along the width direction Z of the second groove, the second groove 62 is spaced apart from the first groove 61, and along the thickness direction X of the first wall portion, the two ends of the projection of the second groove 62 along the extension direction do not extend beyond the two ends of the projection of the first groove 61. The edge of the measuring surface of the predetermined pressure relief area 63 is formed by the projection of the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side close to the predetermined pressure relief area 63) on the first surface 64, the projection of the extended line of the inner edge of the notch of the second groove 62 on the first surface 64, the projection of the inner edge of the notch of the first groove section 611 (the edge of the notch of the first groove section 611 on the side close to the predetermined pressure relief area 63) on the first surface 64, the projection of the extended line of the inner edge of the notch of the first groove section 611 on the first surface 64, the projection of the inner edge of the notch of the second groove section 612 (the edge of the notch of the second groove section 612 on the side close to the predetermined pressure relief area 63) on the first surface 64, and the projection of the extended line of the inner edge of the notch of the second groove section 612 on the first surface 64. The area of ​​the measuring surface of the predetermined pressure relief area 63 is the area of ​​the predetermined pressure relief area 63, and the predetermined pressure relief area 63 is a triangle. When measuring the area of ​​the predetermined pressure relief zone 63, a first straight line can be drawn on the first surface 64 so that the projection of the inner edge of the notch of the second groove 62 on the first surface 64 is located within the first straight line. Then, an extension line of the inner edge of the notch of the first groove section 611 is drawn on the first surface 64 along the extension direction of the inner edge and intersects with the first straight line. Then, an extension line of the inner edge of the notch of the second groove section 612 is drawn on the first surface 64 along the extension direction of the inner edge and intersects with the first straight line, thereby defining a triangular measuring surface. By measuring the base and height of the triangle and multiplying the base by the height, the area of ​​the predetermined pressure relief zone 63 can be calculated.

[0307] In this embodiment, the first groove 61 has a simple structure, and the stress at the position where the first groove section 611 and the second groove section 612 are connected is more concentrated, weaker, and more likely to crack. Therefore, when the battery cell 10 thermally runs away, the pressure relief component 6 can quickly crack from the first groove section 611 and the second groove section 612 after cracking from the position where the first groove section 611 and the second groove section 612 are connected, so that the predetermined pressure relief area 63 is opened more quickly and the pressure is relieved in time.

[0308] 9 and 10 , in some embodiments, the first groove 61 includes a first groove section 611, a second groove section 612, and a third groove section 613. The second groove section 612 and the third groove section 613 are disposed opposite each other. The first groove section 611 connects the second groove section 612 and the third groove section 613. The first groove section 611 is disposed opposite the second groove 62. Along the thickness direction X of the first wall portion, the projection of the first groove section 611, the projection of the second groove section 612, the projection of the extension line of the second groove section 612, the projection of the third groove section 613, the projection of the extension line of the third groove section 613, and the projection of the second groove 62 collectively enclose a predetermined pressure relief area 63.

[0309] The first slot segment 611, the second slot segment 612, and the third slot segment 613 are three slot segments in the first groove 61. The first slot segment 611, the second slot segment 612, and the third slot segment 613 can be linear slots extending along a linear trajectory, or non-linear slots extending along a non-linear trajectory, for example, arcuate slots extending along an arcuate trajectory. If the first slot segment 611, the second slot segment 612, and the third slot segment 613 all extend along a linear trajectory, the first slot segment 611 and the second slot segment 612 can be arranged at an acute angle, a right angle, or an obtuse angle. The first slot segment 611 and the third slot segment 613 can be arranged at an acute angle, a right angle, or an obtuse angle. The second slot segment 612 and the third slot segment 613 can be arranged parallel to each other, or the extension line of the second slot segment 612 and the extension line of the third slot segment 613 can intersect.

[0310] The first trough section 611 connects the second trough section 612 and the third trough section 613. Either end of the first trough section 611 is connected to the second trough section 612 and the third trough section 613, respectively. Alternatively, at least one of the second trough section 612 and the third trough section 613 is connected to a position offset from the end of the first trough section 611, such that at least one of the second trough section 612 and the third trough section 613 is located between the two ends of the first trough section 611. The second trough section 612 can connect to the first trough section 611 at one end or between the two ends of the second trough section 612. The third trough section 613 can connect to the first trough section 611 at one end or between the two ends of the third trough section 613. The first trough section 611, the second trough section 612, and the third trough section 613 can form a U-shaped or H-shaped structure. If the first groove section 611, the second groove section 612, and the third groove section 613 form a U-shaped structure, the first groove 61 of this structure can define a predetermined pressure relief area 63 with a second groove 62. If the first groove section 611, the second groove section 612, and the third groove section 613 form an H-shaped structure, the first groove 61 of this structure can define two predetermined pressure relief areas 63 with two second grooves 62.

[0311] The extension line of the second slot segment 612 is the portion that continues to extend from the end of the second slot segment 612 along the extension direction of the second slot segment 612. The extension line of the third slot segment 613 is the portion that continues to extend from the end of the third slot segment 613 along the extension direction of the third slot segment 613. The extension lines of the second slot segment 612 and the third slot segment 613 are both extension lines 61a of the first groove.

[0312] As an example, in the embodiments shown in Figures 9 and 10, the first slot segment 611, the second slot segment 612, and the third slot segment 613 form an H-shaped structure. There are two predetermined pressure relief areas 63. A portion of the second slot segment 612, a portion of the third slot segment 613, the first slot segment 611, and a second groove 62 collectively define one predetermined pressure relief area 63. Another portion of the second slot segment 612, another portion of the third slot segment 613, the first slot segment 611, and another second groove 62 collectively define another predetermined pressure relief area 63. The first groove 61 is provided on the first surface 64, and the second groove 62 is provided on the second surface 65. Along the width direction Z of the second groove, the second groove 62 is spaced apart from the first groove 61. Along the thickness direction X of the first wall portion, the projection of the second groove 62 extends beyond the projection of the first groove 61 at both ends along the extension direction. The edge of the measuring surface of the predetermined pressure relief area 63 is formed by the projection of the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side close to the predetermined pressure relief area 63) on the first surface 64, the projection of the inner edge of the notch of the first groove section 611 (the edge of the notch of the first groove section 611 on the side close to the predetermined pressure relief area 63) on the first surface 64, the projection of the inner edge of the notch of the second groove section 612 (the edge of the notch of the second groove section 612 on the side close to the predetermined pressure relief area 63) on the first surface 64, the projection of the extended line of the inner edge of the notch of the second groove section 612 on the first surface 64, the projection of the inner edge of the notch of the third groove section 613 (the edge of the notch of the third groove section 613 on the side close to the predetermined pressure relief area 63) on the first surface 64, and the projection of the extended line of the inner edge of the notch of the third groove section 613 on the first surface 64. The predetermined pressure relief area 63 is rectangular. When measuring the area of ​​the predetermined pressure relief zone 63, a first straight line can be drawn on the first surface 64 so that the projection of the inner edge of the notch of the second groove 62 on the first surface 64 is located within the first straight line. Then, an extension line of the inner edge of the notch of the second groove section 612 is drawn on the first surface 64 along the extension direction of the inner edge and intersects with the first straight line. Then, an extension line of the inner edge of the notch of the third groove section 613 is drawn on the first surface 64 along the extension direction of the inner edge and intersects with the first straight line, thereby defining a rectangular measurement surface. By measuring the length and width of the rectangle and multiplying the length by the width, the area of ​​the predetermined pressure relief zone 63 can be calculated.

[0313] In this embodiment, the second groove section 612 and the third groove section 613 are arranged opposite to each other, the first groove section 611 and the second groove 62 are arranged opposite to each other along the width direction of the second groove 62, the first groove section 611 connects the second groove section 612 and the third groove section 613, the intersection position of the first groove section 611 and the second groove section 612 and the connection position of the first groove section 611 and the third groove section 613 are weaker, more likely to crack and open the predetermined pressure relief area 63 for pressure relief, and can further increase the opening area of ​​the predetermined pressure relief area 63, thereby increasing the pressure relief area of ​​the battery cell 10 and improving the pressure relief rate of the battery cell 10.

[0314] In some embodiments, please refer to FIG. 22 , which is a partial view of a housing 1 (where the first groove 61 is an H-shaped groove) provided in other embodiments of the present application. The first groove 61 includes a first groove section 611, a second groove section 612, and a third groove section 613. The second groove section 612 and the third groove section 613 are arranged opposite each other. The first groove section 611 connects the second groove section 612 and the third groove section 613. Along the width direction of the second groove 62, the first groove section 611 and the second groove 62 are arranged opposite each other. Along the thickness direction X of the first wall portion, the projection of the first groove section 611, the projection of the second groove section 612, the projection of the third groove section 613, the projection of the second groove 62, and the projection of the extension line 62a of the second groove together enclose a predetermined pressure relief area 63.

[0315] As an example, in the embodiment shown in FIG22 , the first slot segment 611, the second slot segment 612, and the third slot segment 613 form an H-shaped structure. There are two predetermined pressure relief areas 63. A portion of the second slot segment 612, a portion of the third slot segment 613, the first slot segment 611, and a second groove 62 collectively define one predetermined pressure relief area 63. Another portion of the second slot segment 612, another portion of the third slot segment 613, the first slot segment 611, and another second groove 62 collectively define another predetermined pressure relief area 63. The first groove 61 is provided on the first surface 64 (shown in FIG22 ), and the second groove 62 is provided on the second surface 65 (not shown in FIG22 ). The second groove 62 is located within the area enclosed by the line connecting one end of the second slot segment 612 and one end of the third slot segment 613, and the first groove 61. The edge of the measuring surface of the predetermined pressure relief area 63 is formed by the projection of the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side close to the predetermined pressure relief area 63) on the first surface 64, the projection of the extended line of the two ends of the inner edge of the notch of the second groove 62 on the first surface 64, the projection of the inner edge of the notch of the first groove section 611 (the edge of the notch of the first groove section 611 on the side close to the predetermined pressure relief area 63) on the first surface 64, the projection of the inner edge of the notch of the second groove section 612 (the edge of the notch of the second groove section 612 on the side close to the predetermined pressure relief area 63) on the first surface 64, and the projection of the inner edge of the notch of the third groove section 613 (the edge of the notch of the third groove section 613 on the side close to the predetermined pressure relief area 63) on the first surface 64. The predetermined pressure relief area 63 is rectangular. When measuring the area of ​​the predetermined pressure relief zone 63, a first straight line can be drawn on the first surface 64 so that the projection of the inner edge of the notch of the second groove 62 on the first surface 64 is located within the first straight line, and the two ends of the first straight line extend to the inner edge of the notch of the second groove section 612 and the inner edge of the notch of the third groove section 613, respectively, thereby defining a rectangular measurement surface. By measuring the length and width of the rectangle and multiplying the length by the width, the area of ​​the predetermined pressure relief zone 63 can be calculated.

[0316] In this embodiment, the second groove section 612 and the third groove section 613 are arranged opposite to each other, the first groove section 611 and the second groove 62 are arranged opposite to each other along the width direction of the second groove 62, the first groove section 611 connects the second groove section 612 and the third groove section 613, the intersection position of the first groove section 611 and the second groove section 612 and the connection position of the first groove section 611 and the third groove section 613 are weaker, more likely to crack and open the predetermined pressure relief area 63 for pressure relief, and can further increase the opening area of ​​the predetermined pressure relief area 63, thereby increasing the pressure relief area of ​​the battery cell 10 and improving the pressure relief rate of the battery cell 10.

[0317] In some embodiments, please refer to FIG23 , which is a partial view of a housing 1 (where the first groove 61 is an H-shaped groove) provided in yet other embodiments of the present application. The first groove 61 includes a first groove section 611, a second groove section 612, and a third groove section 613. The second groove section 612 and the third groove section 613 are disposed opposite each other. The first groove section 611 connects the second groove section 612 and the third groove section 613. Along the width direction of the second groove 62, the first groove section 611 and the second groove 62 are disposed opposite each other. Along the thickness direction X of the first wall portion, the projection of the first groove section 611, the projection of the second groove section 612, the projection of the extension line of the second groove section 612, the projection of the third groove section 613, the projection of the extension line of the third groove section 613, the projection of the second groove 62, and the projection of the extension line 62a of the second groove together enclose a predetermined pressure relief area 63.

[0318] As an example, in the embodiment shown in FIG23 , the first slot segment 611, the second slot segment 612, and the third slot segment 613 form an H-shaped structure. There are two predetermined pressure relief areas 63. A portion of the second slot segment 612, a portion of the third slot segment 613, the first slot segment 611, and one second groove 62 collectively define one predetermined pressure relief area 63. Another portion of the second slot segment 612, another portion of the third slot segment 613, the first slot segment 611, and another second groove 62 collectively define another predetermined pressure relief area 63. The first groove 61 is provided on a first surface 64 (not shown in FIG23 ), and the second groove 62 is provided on a second surface 65 (not shown in FIG23 ). Along the width direction Z of the second groove, the second groove 62 is spaced apart from the first groove 61. Along the thickness direction X of the first wall portion, the projection of the second groove 62 does not extend beyond the projection of the first groove 61 at both ends along the extension direction. The edge of the measuring surface of the predetermined pressure relief area 63 is formed by the projection of the inner edge of the notch of the second groove 62 (the edge of the notch of the second groove 62 on the side close to the predetermined pressure relief area 63) on the first surface 64, the projection of the extension line of the inner edge of the notch of the second groove 62 on the first surface 64, the projection of the inner edge of the notch of the first groove section 611 (the edge of the notch of the first groove section 611 on the side close to the predetermined pressure relief area 63) on the first surface 64, the projection of the inner edge of the notch of the second groove section 612 (the edge of the notch of the second groove section 612 on the side close to the predetermined pressure relief area 63) on the first surface 64, the projection of the extension line of the inner edge of the notch of the second groove section 612 on the first surface 64, the projection of the inner edge of the notch of the third groove section 613 (the edge of the notch of the third groove section 613 on the side close to the predetermined pressure relief area 63) on the first surface 64, and the projection of the extension line of the inner edge of the notch of the third groove section 613 on the first surface 64. The predetermined pressure relief area 63 is rectangular. When measuring the area of ​​the predetermined pressure relief zone 63, a first straight line can be drawn on the first surface 64 so that the projection of the inner edge of the notch of the second groove 62 on the first surface 64 is located within the first straight line. Then, an extension line of the inner edge of the notch of the second groove section 612 is drawn on the first surface 64 along the extension direction of the inner edge and intersects with the first straight line. Then, an extension line of the inner edge of the notch of the third groove section 613 is drawn on the first surface 64 along the extension direction of the inner edge and intersects with the first straight line, thereby defining a rectangular measurement surface. By measuring the length and width of the rectangle and multiplying the length by the width, the area of ​​the predetermined pressure relief zone 63 can be calculated.

[0319] In this embodiment, the second groove section 612 and the third groove section 613 are arranged opposite to each other, the first groove section 611 and the second groove 62 are arranged opposite to each other along the width direction of the second groove 62, the first groove section 611 connects the second groove section 612 and the third groove section 613, the intersection position of the first groove section 611 and the second groove section 612 and the connection position of the first groove section 611 and the third groove section 613 are weaker, more likely to crack and open the predetermined pressure relief area 63 for pressure relief, and can further increase the opening area of ​​the predetermined pressure relief area 63, thereby increasing the pressure relief area of ​​the battery cell 10 and improving the pressure relief rate of the battery cell 10.

[0320] In some embodiments, please continue to refer to Figures 22 and 23, the connection position of the second slot segment 612 and the first slot segment 611 deviates from the two ends of the second slot segment 612, and the connection position of the third slot segment 613 and the first slot segment 611 deviates from the two ends of the third slot segment 613, so that a predetermined pressure relief area 63 is formed on both sides of the first slot segment 611.

[0321] The connection position between the second slot segment 612 and the first slot segment 611 is offset from the two ends of the second slot segment 612. That is, the connection position between the second slot segment 612 and the first slot segment 611 is not located at either end of the second slot segment 612. Along the extension direction of the second slot segment 612, the connection position between the second slot segment 612 and the first slot segment 611 is located between the two ends of the second slot segment 612. The connection position between the second slot segment 612 and the first slot segment 611 can be located at the midpoint of the second slot segment 612 or offset from the midpoint of the second slot segment 612.

[0322] The connection position between the third slot segment 613 and the first slot segment 611 is offset from the ends of the third slot segment 613. That is, the connection position between the third slot segment 613 and the first slot segment 611 is not located at either end of the third slot segment 613. Along the extension direction of the third slot segment 613, the connection position between the third slot segment 613 and the first slot segment 611 is located between the ends of the third slot segment 613. The connection position between the third slot segment 613 and the first slot segment 611 can be located at the midpoint of the third slot segment 613 or offset from the midpoint of the third slot segment 613.

[0323] It should be noted that, in the embodiment where the first groove 61 is a multi-stage groove structure, the first groove section 611 , the second groove section 612 and the third groove section 613 are all multi-stage groove structures.

[0324] In this embodiment, the connection position between the second slot segment 612 and the first slot segment 611 is offset from the two ends of the second slot segment 612. During the pressure relief process, after the pressure relief component 6 cracks at the connection position between the second slot segment 612 and the first slot segment 611, the crack can spread along the second slot segment 612 to the two ends of the second slot segment 612, thereby shortening the time it takes for the pressure relief component 6 to crack along the second slot segment 612. The connection position between the third slot segment 613 and the first slot segment 611 is offset from the two ends of the third slot segment 613. During the pressure relief process, after the pressure relief component 6 cracks at the connection position between the third slot segment 613 and the first slot segment 611, the crack can spread along the third slot segment 613 to the two ends of the third slot segment 613, thereby shortening the time it takes for the pressure relief component 6 to crack along the third slot segment 613. In such a structure, the first groove section 611 of the first groove 61 is located between the two predetermined pressure relief areas 63. After the pressure relief component 6 is split along the first groove section 611, the two predetermined pressure relief areas 63 can be opened in a split manner to relieve pressure when the battery cell 10 is depressurized, so that the two predetermined pressure relief areas 63 can be opened quickly, which is beneficial to improving the pressure relief rate of the battery cell 10.

[0325] In some embodiments, the first slot segment 611 extends along a straight line or an arcuate trajectory; and / or, the second slot segment 612 extends along a straight line or an arcuate trajectory; and / or, the third slot segment 613 extends along a straight line or an arcuate trajectory.

[0326] As an example, in the embodiments shown in Figures 22 and 23, the first slot segment 611, the second slot segment 612 and the third slot segment 613 all extend along a straight line, and the second slot segment 612 and the third slot segment 613 are both perpendicular to the first slot segment 611.

[0327] If the first groove section 611 extends along a straight trajectory, the first groove section 611 is a straight groove, which can reduce the difficulty of forming the first groove section 611. If the first groove section 611 extends along an arc trajectory, the first groove section 611 is an arc-shaped groove, and the pressure relief component 6 is more likely to split along the first groove section 611 when the battery cell 10 releases pressure, thereby achieving a faster opening of the predetermined pressure relief area 63. If the second groove section 612 extends along a straight trajectory, the second groove section 612 is a straight groove, which can reduce the difficulty of forming the second groove section 612. If the second groove section 612 extends along an arc trajectory, the second groove section 612 is an arc-shaped groove, and the pressure relief component 6 is more likely to split along the second groove section 612 when the battery cell 10 releases pressure, thereby achieving a faster opening of the predetermined pressure relief area 63. If the third groove section 613 extends along a straight trajectory, the third groove section 613 is a straight groove, which can reduce the difficulty of forming the third groove section 613. If the third groove section 613 extends along an arc trajectory, the third groove section 613 is an arc-shaped groove, and the pressure relief component 6 is more likely to break along the third groove section 613 when the battery cell 10 releases pressure, thereby achieving faster opening of the predetermined pressure relief area 63.

[0328] In some embodiments, please refer to FIG24 , which is an exploded view of the housing 1 (one end of the housing 11 is open, the housing 11 includes a first wall portion 13, and the pressure relief component 6 is the first wall portion 13) provided in some embodiments of the present application. The pressure relief component 6 is integrally formed with the first wall portion 13.

[0329] The entire first wall portion 13 can serve as the pressure relief component 6, or a portion of the first wall portion 13 can serve as the pressure relief component 6, so that the pressure relief component 6 and the first wall portion 13 are integrally formed. The first groove 61 and the second groove 62 are both provided in the first wall portion 13. One of the first surface 64 and the second surface 65 of the pressure relief component 6 is the inner surface of the first wall portion 13, and the other is the outer surface of the first wall portion 13.

[0330] In this embodiment, the pressure relief component 6 is integrally formed with the first wall portion 13, and the first groove 61 and the second groove 62 can be directly formed on the first wall portion 13 to form an integrated pressure relief structure, which has higher reliability, eliminates the installation process of the pressure relief component 6, and has better economy.

[0331] In some embodiments, the first groove 61 is stamped and formed on the first wall portion 13 ; and / or the second groove 62 is stamped and formed on the first wall portion 13 .

[0332] If the first groove 61 is a primary groove structure, when forming the first groove 61 on the first wall portion 13, the first wall portion 13 can be punched once to punch out the first groove 61 on the first wall portion 13; if the first groove 61 is a multi-stage groove structure, when forming the first groove 61 on the first wall portion 13, the first wall portion 13 can be punched multiple times, each time punching out a primary groove, and the first groove 61 is finally formed after multiple stampings.

[0333] In this embodiment, if the first groove 61 is stamped and formed in the first wall portion 13, the first groove 61 is formed in a simple manner, which helps reduce the production cost of the battery cell 10. If the second groove 62 is stamped and formed in the first wall portion 13, the second groove 62 is formed in a simple manner, which helps reduce the production cost of the battery cell 10.

[0334] In some embodiments, please refer to FIG. 25 , which is an exploded view of a housing 1 (an opening is formed at one end of the housing 11, the housing 11 includes a first wall 13, and a pressure relief component 6 is mounted on the first wall 13) provided in some embodiments of the present application. The pressure relief component 6 is provided separately from the first wall 13 and is mounted on the first wall 13.

[0335] The pressure relief component 6 and the housing 1 are separate components. The pressure relief component 6 is manufactured separately and then mounted on the first wall portion 13. The pressure relief component 6 can be mounted on the first wall portion 13 by welding, riveting, bonding, or other methods. As an example, the first wall portion 13 is provided with a pressure relief hole 131. The pressure relief component 6 covers the pressure relief hole 131 and is welded to the first wall portion 13.

[0336] In this embodiment, the pressure relief component 6 is a component independent of the housing 1 , and the pressure relief component 6 and the housing 1 can be produced and assembled separately, with low production difficulty and high efficiency.

[0337] In some embodiments, the first wall portion 13 is a rectangular wall portion, and the first groove 61 and the second groove 62 are arranged along the width direction of the first wall portion 13 .

[0338] The housing 1 may be in the shape of a rectangular parallelepiped, and the first wall 13 may be any rectangular wall in the housing 1. The first wall 13 is a rectangular wall, that is, when viewed along the thickness direction of the first wall 13, the first wall 13 is generally in the shape of a rectangle. The length of the first wall 13 is greater than its width.

[0339] The first groove 61 and the second groove 62 are arranged along the width direction of the first wall portion 13. The first groove 61 and the second groove 62 can be spaced apart along the width direction of the first wall portion 13, or the projection of the first groove 61 along the thickness direction X of the first wall portion and the projection of the second groove 62 along the thickness direction X of the first wall portion are just connected in the width direction of the first wall portion 13. Taking the H-shaped first groove 61 as an example, the second groove section 612 and the third groove section 613 of the first groove 61 may both be at a certain distance from the second groove 62 along the width direction of the first wall portion 13, so that the first groove 61 and the second groove 62 are spaced apart along the width direction of the first wall portion 13. Alternatively, the projection of at least one of the second groove section 612 and the third groove section 613 of the first groove 61 along the thickness direction X of the first wall portion at one end of the extension direction just extends along the width direction of the first wall portion 13 to the projection of the second groove 62 along the thickness direction X of the first wall portion, so that the projection of the first groove 61 along the thickness direction X of the first wall portion and the projection of the second groove 62 along the thickness direction X of the first wall portion just connect in the width direction of the first wall portion 13.

[0340] As an example, the width direction of the first wall portion 13 is parallel to the width direction Z of the second groove.

[0341] In this embodiment, the first groove 61 and the second groove 62 are arranged along the width direction of the first wall portion 13, so that the second groove 62 is closer to the edge of the first wall portion 13 in the width direction of the first wall portion 13. This provides greater strength in the area where the second groove 62 is provided in the pressure relief member 6, thereby reducing the risk of the pressure relief member 6 cracking along the second groove 62 when the battery cell 10 releases pressure. Furthermore, during use, the battery cell 10 expands more in the width direction of the first wall portion 13 than in the length direction of the first wall portion 13, and this expansion of the battery cell 10 in the width direction of the first wall portion 13 has a greater impact on the pressure relief member 6. Since the first groove 61 and the second groove 62 are arranged along the width direction of the first wall portion 13, the second groove 62 can effectively absorb the deformation energy of the battery cell 10 when it expands and deforms in the width direction of the first wall portion 13, thereby reducing the impact of the expansion of the battery cell 10 in the width direction of the first wall portion 13 on the pressure relief member 6.

[0342] In some embodiments, please refer to Figures 24 to 27. Figure 26 is an exploded view of the housing 1 provided in some embodiments of the present application (an opening is formed at one end of the housing 11, and the end cover 12 is a pressure relief component 6); Figure 27 is an exploded view of the housing 1 provided in some embodiments of the present application (an opening is formed at one end of the housing 11, the end cover 12 is a first wall portion 13, and the pressure relief component 6 is installed on the first wall portion 13). An opening is formed at least at one end of the housing 11. The end cover 12 corresponds to the opening one-to-one, and the end cover 12 closes the opening. Among them, at least one end cover 12 is the first wall portion 13; and / or, at least one wall portion in the housing 11 is the first wall portion 13.

[0343] The shell 11 may have only one opening, for example, the shell 11 may have an opening formed at only one end; the shell 11 may also have multiple openings, for example, the shell 11 may have openings formed at both opposite ends. The number of end caps 12 is the same as the number of openings of the shell 11. It is understandable that if the shell 11 has only one opening, there is one end cap 12; if the shell 11 has two openings, there are two end caps 12. One or more end caps 12 may be the first wall portion 13, or one or more wall portions in the shell 11 may be the first wall portion 13. In the embodiment in which the shell 11 has an opening formed at one end, the positive electrode terminal and the negative electrode terminal may be provided on the end cap 12, and the positive electrode tab and the negative electrode tab may be formed at the end of the electrode assembly 2 facing the end cap 12, so as to be electrically connected to the positive electrode terminal and the negative electrode terminal, respectively. In an embodiment in which openings are formed at both opposite ends of the shell 11, the positive electrode terminal can be provided at one end cover 12, the negative electrode terminal can be provided at the other end cover 12, and the positive electrode ear and the negative electrode ear can be respectively formed at the opposite ends of the electrode assembly 2 to facilitate electrical connection between the positive electrode ear and the positive electrode terminal and the negative electrode ear and the negative electrode terminal.

[0344] In the embodiment shown in FIG24 , an opening is formed at one end of the housing 11, the wall portion of the housing 11 opposite the end cover 12 is the first wall portion 13, and the pressure relief component 6 is the first wall portion 13. In the embodiment shown in FIG25 , an opening is formed at one end of the housing 11, the wall portion of the housing 11 opposite the end cover 12 is the first wall portion 13, and the pressure relief component 6 is mounted on the first wall portion 13. In the embodiment shown in FIG26 , an opening is formed at one end of the housing 11, the end cover 12 is the first wall portion 13 (not shown in FIG26 ), and the first wall portion 13 is the pressure relief component 6. In the embodiment shown in FIG27 , an opening is formed at one end of the housing 11, the end cover 12 is the first wall portion 13, and the pressure relief component 6 is mounted on the first wall portion 13.

[0345] In this embodiment, if at least one end cap 12 is a first wall portion 13, so that at least one end cap 12 has a pressure relief function, the difficulty of forming the first groove 61 and the second groove 62 on the end cap 12 or the difficulty of installing the pressure relief component 6 is lower. If at least one wall portion in the shell 11 is a first wall portion 13, so that the shell 11 has a pressure relief function, when the battery cell 10 is depressurized, the emissions discharged from the inside of the battery cell 10 are less likely to affect the external components outside the end cap 12, thereby reducing the risk of external components being damaged by emissions. The external components can be a conduit component connected to the electrode terminal 3, a temperature detection component, a voltage detection component, etc. The emissions include but are not limited to: electrolyte, dissolved or split positive and negative electrode sheets, fragments of the separator, high-temperature and high-pressure gas generated by the reaction, flames, etc.

[0346] In some embodiments, please continue to refer to Figures 24 and 25 , the shell 11 is formed with an opening only at one end, and the wall portion of the shell 11 opposite to the end cover 12 is the first wall portion 13.

[0347] As an example, the shell 11 is in a rectangular parallelepiped shape and further includes four side walls. The four side walls are arranged around the first wall portion 13 . The four side walls and the first wall portion 13 together define a space inside the shell 11 .

[0348] In this embodiment, the housing 11 is open at one end, simplifying the structure of the entire battery cell 10. The first wall 13 is the wall of the housing 11 opposite the end cap 12, and can achieve directional pressure relief from the bottom of the housing 11.

[0349] In some embodiments, please refer to FIG28 , which is an exploded view of a battery cell 10 provided in some other embodiments of the present application. Openings are formed at opposite ends of the housing 11 , and at least one wall portion of the housing 11 is a first wall portion 13 .

[0350] In the housing 11 , one wall portion or multiple walls may be the first wall portion 13 . The pressure relief component 6 may be the first wall portion 13 , or may be mounted on the first wall portion 13 .

[0351] In the embodiment shown in FIG28 , the housing 11 is in the shape of a rectangular parallelepiped and includes four walls, which are connected in sequence at their ends and collectively define the space within the housing 11. Two opposing walls are large-area walls, while the other two are small-area walls. The outer surface areas of the large-area walls are larger than those of the small-area walls. One or two of the small-area walls in the housing 11 are first walls 13.

[0352] In this embodiment, the housing 11 has openings at both opposing ends. The electrode assembly 2 can be assembled into the housing 11 through either opening, which reduces the difficulty of assembling the battery cell 10 and improves the assembly quality of the battery cell 10. This structure of the housing 11 allows for a longer length (openings are formed at both ends of the housing 11 in the longitudinal direction), which helps increase the capacity of the battery cell 10.

[0353] In some embodiments, the pressure relief component 6 is made of steel.

[0354] The steel material can be carbon steel, alloy steel, stainless steel, etc.

[0355] It is understood that in the embodiment where the pressure relief component 6 and the first wall portion 13 are integrally formed, the material of the first wall portion 13 includes steel. If the first wall portion 13 is the end cap 12, the end cap 12 can be made of steel; if the first wall portion 13 is a wall portion in the housing 11, the housing 11 can be made of steel.

[0356] In this embodiment, steel has the characteristic of high strength, and the pressure relief component 6 made of steel has greater strength. Under the condition of a constant burst pressure of the battery cell 10, the pressure relief component 6 can be made thinner, thereby reducing the volume of the pressure relief component 6. In the embodiment where the pressure relief component 6 is integrally formed with the first wall portion 13, the first wall portion 13 is made of steel and can be made thinner. Under the condition of a constant volume of the outer shell 1, the volume of the outer shell 1 can be increased to provide more space for the electrode assembly 2, which is conducive to improving the volumetric energy density of the battery cell 10.

[0357] In some embodiments, the steel material is carbon steel or stainless steel.

[0358] Carbon steel can be low carbon steel, medium carbon steel or high carbon steel.

[0359] In some embodiments, the pressure relief component 6 is made of aluminum alloy.

[0360] It is understood that in the embodiment where the pressure relief component 6 and the first wall portion 13 are integrally formed, the material of the first wall portion 13 includes an aluminum alloy. If the first wall portion 13 is the end cap 12, the end cap 12 can be made of an aluminum alloy; if the first wall portion 13 is a wall portion in the housing 11, the housing 11 can be made of an aluminum alloy.

[0361] Aluminum alloy has the characteristics of light weight and good ductility, and it is easier to process the first groove 61 and the second groove 62 on the pressure relief component 6. In the embodiment where the pressure relief component 6 and the first wall portion 13 are integrally formed, the first wall portion 13 is made of aluminum alloy, which can effectively reduce the difficulty of forming the first wall portion 13. Since aluminum alloy has good ductility, it is easier to pile materials in the predetermined pressure relief area 63 when forming the first groove 61. However, controlling V / A to 0.05mm~0.5mm can effectively reduce the impact of the piling of materials in the predetermined pressure relief area 63 on the performance of the battery cell 10, thereby improving the flatness of the surface of the pressure relief component 6 where the first groove 61 is set, taking into account the service life requirements of the battery cell 10 during normal use and the reliability requirements of the battery cell 10 during thermal runaway.

[0362] 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%.

[0363] This aluminum alloy belongs to the third series aluminum, has lower hardness and better forming ability, reduces the processing difficulty of the first groove 61 and the second groove 62, is conducive to improving the processing accuracy of the first groove 61 and the second groove 62, and improves the pressure relief consistency of the pressure relief component 6.

[0364] In some embodiments, the aluminum alloy includes the following components in mass percentage: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other individual element components ≤ 0.05%, and the total composition of other elements ≤ 0.15%.

[0365] This aluminum alloy belongs to the fifth series aluminum. The pressure relief component 6 made of this aluminum alloy has higher hardness, greater strength, and good anti-destruction ability. The embodiment of the present application provides a battery 100, including the battery cell 10 provided by any of the above embodiments.

[0366] An embodiment of the present application provides an electrical device, comprising a battery cell 10 provided by any one of the above embodiments, and the battery cell 10 is used to provide electrical energy to the electrical device.

[0367] The present embodiment further provides a battery cell 10, comprising a housing 1 and an electrode assembly 2, wherein the electrode assembly 2 has a positive tab and a negative tab, and the electrode assembly 2 is housed within the housing 1. The housing 1 is rectangular and comprises a shell 11 and an end cap 12. The shell 11 has an opening at one end, and the end cap 12 seals the opening. The end cap 12 is provided with a positive electrode terminal and a negative electrode terminal. The positive electrode terminal is electrically connected to the positive tab via a current collecting member 4, and the negative electrode terminal is electrically connected to the negative tab via another current collecting member 4.

[0368] The housing 11 is made of aluminum alloy. The wall of the housing 11 opposite the end cap 12 is the pressure relief component 6. The pressure relief component 6 is a rectangular wall. The outer surface of the pressure relief component 6 is provided with a first groove 61, and the inner surface of the pressure relief component 6 is provided with two second grooves 62. Along the width direction of the pressure relief component 6, the first groove 61 is located between the two second grooves 62, and the second groove 62 is spaced apart from the first groove 61. The minimum residual thickness of the first groove 61 is less than the minimum residual thickness of the second groove 62. The first groove 61 has an H-shaped structure and includes a first groove section 611, a second groove section 612, and a third groove section 613. The first, second, and third groove sections 611, 612, 613 all extend along straight lines. The second and third groove sections 612, 613 are arranged in parallel. The first groove section 611 connects the second and third groove sections 612, 613. The second and third groove sections 612, 613 are both perpendicular to the first groove section 611. The connection between the first and second groove sections 611, 612 is located at the midpoint of the second groove section 612, and the connection between the first and third groove sections 611, 613 is located at the midpoint of the third groove section 613. Along the thickness direction X of the first wall portion, the projection of the second groove 62 extends from both ends of the extension direction to form the second and third groove sections 612, 613, respectively. The first groove 61 is a stepped groove and includes two stages, each of which has an H-shaped structure. Among them, along the thickness direction X of the first wall portion, the projection of the first groove section 611, the projection of the second groove section 612, the projection of the extension line of the second groove section 612, the third groove section 613, the projection of the extension line of the third groove section 613 and the projection of the two second grooves 62 together enclose two predetermined pressure relief areas 63. The two predetermined pressure relief areas 63 are respectively located on both sides of the first groove section 611. The pressure relief component 6 is configured to be able to split along at least a portion of the first groove 61 when the battery cell 10 is depressurized. The second groove 62 is configured to be able to guide at least a portion of the predetermined pressure relief area 63 to flip over to open at least a portion of the predetermined pressure relief area 63. The volume of the first groove 61 is V, and the sum of the areas of all predetermined pressure relief areas 63 is A, satisfying: 0.05mm≤V / A≤0.5mm, 82mm 3 ≤V≤450mm 3 , 160mm 2 ≤A≤1500mm 2.

[0369] Along the width direction Z of the second groove, the second groove 62 includes a first groove side surface 621 and a second groove side surface 622 that are oppositely arranged and connected to the inner surface of the pressure relief component 6. The first groove side surface 621 is closer to the predetermined pressure relief area 63 than the second groove side surface 622. The angle between the first groove side surface 621 and the inner surface of the pressure relief component 6 is a, and the angle between the second groove side surface 622 and the inner surface of the pressure relief component 6 is b, satisfying: 90°≤a<b<180°.

[0370] In such a battery cell 10, 0.05mm≤V / A≤0.5mm, which not only improves the smoothness of the surface of the first groove 61 of the pressure relief component 6, but also takes into account the service life requirements of the battery cell 10 during normal use and the reliability requirements of the battery cell 10 during thermal runaway. a<b, which makes the inclination angle of the first groove side 621 smaller than that of the second groove side 622, is equivalent to reducing the angle between the first groove side 621 and the second surface 65. This can reduce the amount of excess material extruded during the formation of the first groove 61 and the accumulation of material in the predetermined pressure relief area 63. This also reduces the height of the material accumulation protrusion on the surface of the predetermined pressure relief area 63 caused by material extrusion in the area where the first groove 61 of the pressure relief component 6 is located, further improving the smoothness of the surface of the first groove 61 of the pressure relief component 6.

[0371] 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.

[0372] The features and performance of the present application are further described in detail below with reference to the embodiments.

[0373] The battery cells 10 in each embodiment and comparative example were prepared and tested according to the following methods.

[0374] 1. Preparation of Battery Cell 10

[0375] 1. Preparation of positive electrode

[0376] 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 0.1The 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.

[0377] 2. Preparation of negative electrode sheet

[0378] 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.

[0379] 3. Preparation of Electrolyte

[0380] 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.

[0381] 4. Isolation

[0382] A 16 μm polyethylene film was used as a separator.

[0383] 5. Preparation of Battery Cell 10

[0384] 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 2 is wound and placed in an aluminum shell 1. The prepared electrolyte is injected into the dried shell 1. The battery cell 10 is prepared by packaging, standing, forming, shaping, and capacity testing.

[0385] The battery cells 10 in each embodiment and comparative example were prepared using the above-described method. The battery cells 10 in each embodiment and comparative example used the same chemical system. The difference between the battery cells 10 in each embodiment and comparative example lies in the different volumes V of the first groove 61 and the sum A of the areas of all predetermined pressure relief areas 63 on the first wall 13. In each embodiment and comparative example, the housing 1 of the battery cell 10 has a rectangular parallelepiped structure. The shell 11 of the housing 1 is open only at one end and is made of aluminum alloy. The wall of the shell 11 opposite the end cap 12 is the first wall 13, which serves as the pressure relief member 6. The first wall 13 is a rectangular wall. The first groove 61 has an H-shaped structure and is a two-stage groove. The first groove 61 is provided on the outer surface of the first wall 13, and the second groove 62 is provided on the inner surface of the first wall 13. Along the width of the first wall 13, the first groove 61 is located between the two second grooves 62.

[0386] 2. Performance parameter testing

[0387] 1. Method for measuring the number of cycle fatigue of battery cell 10

[0388] 1) Prepare a special test fixture. Specifically, the fixture includes three 10mm steel plates (first steel plate, second steel plate, and third steel plate). Each steel plate can completely cover the large surface of the battery cell 10 (the outer surface of the shell 11 perpendicular to the width direction of the first wall portion 13). The first steel plate and the third steel plate are located at both ends of the fixture and are fixed by bolts. The second steel plate is located between the first and third steel plates, and the second steel plate is constrained by a guide rail. The second steel plate can only move translationally along the thickness direction of the second steel plate.

[0389] 2) The battery cell 10 is installed between the first steel plate and the second steel plate, and a support structure is placed between the large surface of one side of the battery cell 10 and the first steel plate, and between the large surface of the other side and the second steel plate. The support structure can be an insulation pad or a water-cooling plate (consistent with the material / structure between two adjacent battery cells 10 in the actual battery 100). The support structure can be compressed to provide expansion space for the battery cell 10 during the charge and discharge cycle aging process; the large surface of the battery cell 10 is in contact with the support structure, the first steel plate is in contact with the corresponding support structure, the second steel plate is in contact with the corresponding support structure, and a pressure sensor is provided between the second steel plate and the third steel plate.

[0390] 3) Adjust the position of the second steel plate by adjusting the pre-tightening force of the bolts, observe the pressure sensor, make the initial extrusion force on the battery cell 10 2000N, and connect the positive electrode terminal and the positive electrode terminal of the battery cell 10 to the charging and discharging equipment.

[0391] 4) Place the battery cell 10 and the fixture in a constant temperature environment of 25±2°C, and start the test after the battery cell 10 reaches temperature equilibrium.

[0392] 5) The test steps are carried out in accordance with Section 6.4 "Standard Cycle Life" of GBT31484-2015 Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles, and the test cycle end condition is changed to "stop testing until damage occurs at the first groove 61 provided on the first wall portion 13".

[0393] Specifically, test according to the following steps:

[0394] a) Discharge to 2.8V with a current of 1I1(A);

[0395] b) Leave it for no less than 30 minutes;

[0396] c) Charge in accordance with the method 6.1.1.3 of GBT31484-2015 Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles;

[0397] d) Leave it for no less than 30 minutes;

[0398] e) Discharge to 2.8V at a current of 1I1(A);

[0399] f) Repeat steps b) to e) until the first wall portion 13 where the first groove 61 is provided is damaged and the test is stopped.

[0400] That is, during the test, the area where the first groove 61 is provided on the first wall portion 13 of the battery cell 10 is continuously observed until the area breaks and leaks. The number of cycles is recorded as the cycle fatigue number of the battery cell 10. The greater the cycle fatigue number of the battery cell 10, the lower the probability of the battery cell 10 opening the valve and leaking liquid due to gas production during long-term use, and the longer the service life.

[0401] 2. Thermal runaway test method for battery cell 10

[0402] 1. Select the heating plate according to the size of the battery cell 10. The size of the heating plate should cover as much of the battery cell 10 as possible (coverage area ≥ 60%);

[0403] 2. Before testing, charge the battery cell 10 to 100% SOC and place the battery cell 10 in a constant temperature environment of 25±2°C;

[0404] 3. Sensor layout:

[0405] 1) Arrangement of temperature-sensing wires: A layer of Teflon is applied to the center of the two large surfaces of the battery cell 10, and a temperature-sensing wire is arranged above the Teflon, followed by another layer of Teflon.

[0406] 2) Layout of voltage sampling line: A layer of Teflon is applied to the positive electrode terminal, the positive electrode terminal and the housing 1 of the battery cell 10, a voltage sampling line is arranged above the Teflon, and another layer of Teflon is applied;

[0407] 3) Air pipe arrangement: Drill a hole in the first wall 13 of the battery cell 10 at the midpoint between the first groove 61 and the side surface of the housing 11 (the outer surface of the wall of the housing 11 adjacent to the first wall 13 along the length of the first wall 13). Insert the air pipe into the hole and seal it. Connect the air pipe to the air pressure sensor.

[0408] 4) Connect the temperature sensing wire, voltage sampling wire and air pressure sensor to the data acquisition instrument to collect and analyze data in real time. The acquisition frequency of the data acquisition instrument is ≤0.1S;

[0409] 4. Assembly fixture: The fixture is used to completely cover the large surface of the battery cell 10 (the outer surface of the housing 11 perpendicular to the width direction of the first wall 13). The clamping force is 3000N. The arrangement order of the fixture, heating plate and battery cell 10 is: fixture + heating plate + battery cell 10 + fixture.

[0410] 5. Test: Turn on the data acquisition instrument to collect temperature, voltage, and air pressure data, then turn on the heating plate at a power of 500W to heat the battery cell 10 until the battery cell 10 thermally runs away.

[0411] 6. Obtaining the pressure holding time of the battery cell 10: Determine the thermal runaway moment and the valve opening moment based on the temperature, voltage, and air pressure data collected by the data acquisition instrument, and obtain the pressure holding time of the battery cell 10 based on the formula: pressure holding time = valve opening moment - thermal runaway moment.

[0412] Thermal runaway criteria: a) The triggering object generates a voltage drop exceeding 25% of the initial voltage; b) The temperature at the detection point reaches the manufacturer's maximum operating temperature; c) The temperature rise rate dT / dt at the detection point is ≥ 1°C / s and persists for more than 3 seconds. Thermal runaway is determined to have occurred when a) and c) or b) and c) occur, and the moment of thermal runaway is determined.

[0413] Valve opening timing determination: When the air pressure drops by more than 25%, the valve is considered open (the first wall portion 13 ruptures along at least a portion of the first groove 61). The moment the air pressure begins to drop is the valve opening timing. Both the valve opening timing and the thermal runaway timing can be obtained from the data logger.

[0414] 3. Method for measuring the flatness difference of the outer surface of the first wall portion 13

[0415] Four measurement points are taken on the outer surface of the first wall portion 13 near both ends along the length of the first wall portion 13 (in this area, the first groove 61 is not provided). The flatness of the four measurement points is measured, and the average flatness of the four measurement points is calculated to obtain a reference flatness value. Then, two experimental points are taken on the outer surface of the first wall portion 13, located in the predetermined pressure relief area 63 and close to the first groove section 611, the second groove section 612, and the third groove section 613. The flatness of the six experimental points is measured, and the average flatness of the six experimental points is calculated to obtain an experimental flatness value. Finally, the reference value is subtracted from the experimental value to obtain the flatness difference of the outer surface of the first wall portion 13.

[0416] 3. Test Results

[0417] The performance test results of the battery cells 10 in various embodiments and comparative examples are shown in Table 1, and are as follows:

[0418] Table 1

[0419] As shown in Table 1, a comparison of Examples 1-17 with Comparative Examples 1-2 shows that when V / A ≥ 0.05 mm, the battery cell 10 has a shorter holding time during thermal runaway. This results in a lower burst pressure for the battery cell 10 and more timely pressure relief during thermal runaway, reducing the risk of explosion and improving the reliability of the battery cell 10. A comparison of Examples 1-17 with Comparative Examples 3-4 shows that when V / A ≤ 0.5 mm, the flatness difference of the outer surface of the first wall portion 13 (the surface of the first wall portion 13 where the first groove 61 is provided) is smaller, improving the flatness of the outer surface of the first wall portion 13. Furthermore, the battery cell 10 has a higher number of fatigue cycles, improving the fatigue resistance of the region of the first wall portion 13 where the first groove 61 is provided, and effectively increasing the service life of the battery cell 10.

[0420] Comparing Examples 4-9 with Examples 1-3, it can be seen that when V / A ≥ 0.1 mm, the holding time of the battery cell 10 during thermal runaway is shorter, and the pressure release of the battery cell 10 during thermal runaway is more timely, which can further improve the reliability of the battery cell 10. Comparing Examples 4-9 with Examples 10-17, it can be seen that when V / A ≤ 0.35 mm, the flatness of the outer surface of the first wall portion 13 is further improved, the number of cycle fatigue cycles of the battery cell 10 is increased, and the service life of the battery cell 10 is further improved.

[0421] The above embodiments are only used to illustrate the technical solutions of the present application and are not used to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application. The above embodiments are only used to illustrate the technical solutions of the present application and are not used to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A battery cell, comprising: A housing including a first wall portion; A pressure relief component disposed on the first wall portion, the pressure relief component including a first groove and a second groove. Along the thickness direction of the first wall portion, the projection of the first groove and the projection of at least one of the second grooves jointly define at least one predetermined pressure relief area. The pressure relief component is configured to be able to crack along at least a part of the first groove when the battery cell relieves pressure, and the second groove is configured to guide at least a part of the predetermined pressure relief area to flip to open at least a part of the predetermined pressure relief area; Wherein, the volume of the first groove is V, and the sum of the areas of all the predetermined pressure relief areas is A, satisfying: 0.05 mm ≤ V / A ≤ 0.5 mm.

2. The battery cell according to claim 1, wherein, 0.1 mm ≤ V / A ≤ 0.35 mm.

3. The battery cell according to claim 1 or 2, wherein 82 mm 3 ≤ V ≤ 450 mm 3 .

4. The battery cell according to claim 3, wherein, 115mm 3 ≤V≤265mm 3 。 5. The battery cell according to any one of claims 1-4, wherein, 160mm 2 ≤A≤1500mm 2 。 6. The battery cell according to claim 5, wherein, 400mm 2 ≤A≤1200mm 2 。 7. The battery cell according to any one of claims 1-6, wherein, Along the thickness direction of the first wall portion, the pressure relief component has opposite first and second surfaces, and the second groove is recessed from the second surface towards the direction close to the first surface; Along the width direction of the second groove, the second groove includes a first groove side surface and a second groove side surface that are oppositely arranged and connected to the second surface. The first groove side surface is closer to the predetermined pressure relief area than the second groove side surface. The angle formed by the first groove side surface and the second surface is a, and the angle formed by the second groove side surface and the second surface is b, satisfying: 90° ≤ a < b < 180°. The width direction of the second groove is perpendicular to the thickness direction of the first wall portion.

8. The battery cell according to claim 7, wherein, 90°≤a≤150°。 9. The battery cell according to claim 7 or 8, wherein, 90°＜b≤170°。 10. The battery cell according to any one of claims 1-9, wherein, The pressure relief component is provided with a plurality of the second grooves. Along the thickness direction of the first wall portion, the projection of the first groove and the projections of the plurality of second grooves jointly define a plurality of the predetermined pressure relief areas, and each of the predetermined pressure relief areas is correspondingly arranged with one or more of the second grooves.

11. The battery cell according to any one of claims 1-10, wherein, Along the thickness direction of the first wall portion, the projection of the second groove does not overlap with the projection of the first groove.

12. The battery cell according to claim 11, wherein, Along the width direction of the second groove, the second groove is spaced from the first groove, and the width direction of the second groove is perpendicular to the thickness direction of the first wall portion.

13. The battery cell according to any one of claims 1-12, wherein, Along the thickness direction of the first wall portion, the projections of the second groove at both ends along the extending direction respectively extend out of the two ends of the projection of the first groove.

14. The battery cell according to any one of claims 1-13, wherein, The minimum remaining thickness of the first groove is D1, and the minimum remaining thickness of the second groove is D2, satisfying: D1 < D2.

15. The battery cell according to claim 14, wherein, Along the thickness direction of the first wall portion, the maximum groove depth of the first groove is H1, and the maximum groove depth of the second groove is H2, satisfying: H2 < H1.

16. The battery cell according to any one of claims 1-15, wherein, Along the thickness direction of the first wall portion, the maximum groove depth of the first groove is H1, and the thickness of the pressure relief component is D, 0.16 ≤ H1 / D < 1.

17. The battery cell according to claim 16, wherein, 0.4 mm ≤ H1 ≤ 2 mm, 0.8 mm ≤ D ≤ 2.5 mm.

18. The battery cell according to any one of claims 1-17, wherein, Along the thickness direction of the first wall portion, the pressure relief component has opposite first and second surfaces, the first groove is disposed on the first surface, and the second groove is disposed on the second surface.

19. The battery cell according to claim 18, wherein, In the width direction of the second groove, the projection of the first groove and the projection of the second groove at least partially overlap, and the width direction of the second groove is perpendicular to the thickness direction of the first wall portion.

20. The battery cell according to claim 18 or 19, wherein, In the thickness direction of the first wall portion, the bottom surface of the second groove is closer to the first surface than the bottom surface of the first groove.

21. The battery cell according to any one of claims 18-20, wherein, In the thickness direction of the first wall portion, the maximum groove depth of the second groove is H2, and the minimum remaining thickness of the first groove is D1, satisfying: D1 < H2.

22. The battery cell according to any one of claims 18-21, wherein, The first groove includes multiple stages of grooves arranged in sequence in the direction from the first surface to the second surface. In the thickness direction of the first wall portion, among two adjacent stages of grooves, the stage of groove farther from the first surface is disposed on the bottom surface of the stage of groove closer to the first surface; Among them, the stage of groove disposed on the first surface in the multiple stages of grooves is the first-stage groove. In the width direction of the second groove, the projection of the second groove and the projection of the first-stage groove at least partially overlap, and the width direction of the second groove is perpendicular to the thickness direction of the first wall portion.

23. The battery cell according to claim 22, wherein, In the thickness direction of the first wall portion, the bottom surface of the second groove is flush with the bottom surface of the first-stage groove, or the bottom surface of the second groove is closer to the first surface than the bottom surface of the first-stage groove.

24. The battery cell according to any one of claims 1-17, wherein, In the thickness direction of the first wall portion, the pressure relief component has opposite first and second surfaces, and both the first groove and the second groove are recessed from the second surface towards the direction close to the first surface.

25. The battery cell according to claim 24, wherein, The first groove includes multiple stages of grooves arranged in sequence in the direction from the second surface to the first surface. In the thickness direction of the first wall portion, among two adjacent stages of grooves, the stage of groove farther from the second surface is disposed on the bottom surface of the stage of groove closer to the second surface; Among them, the stage of groove disposed on the second surface in the multiple stages of grooves is the first-stage groove. In the thickness direction of the first wall portion, the bottom surface of the first-stage groove is closer to the second surface than the bottom surface of the second groove.

26. The battery cell according to claim 25, wherein, In the thickness direction of the first wall portion, the maximum groove depth of the second groove is H2, and the maximum groove depth of the first-stage groove is H3, satisfying: H3 < H2.

27. The battery cell according to any one of claims 18-26, wherein, The first surface is the surface of the pressure relief component facing the outside of the battery cell, and the second surface is the surface of the pressure relief component facing the inside of the battery cell.

28. The battery cell according to any one of claims 1-27, wherein, In the thickness direction of the first wall portion, the projection of the first groove, the projection of the second groove, and the projection of the extension line of the second groove jointly enclose the predetermined pressure relief area; Or In the thickness direction of the first wall portion, the projection of the first groove, the projection of the extension line of the first groove, and the projection of the second groove jointly enclose the predetermined pressure relief area; Or In the thickness direction of the first wall portion, the projection of the first groove, the projection of the extension line of the first groove, the projection of the second groove, and the projection of the extension line of the second groove jointly enclose the predetermined pressure relief area.

29. The battery cell according to claim 28, wherein, The first groove extends along an arc trajectory; and / or, the second groove extends along a straight line trajectory.

30. The battery cell according to any one of claims 1-28, wherein, The first groove includes a first groove section and a second groove section, and the first groove section is connected to the second groove section; In the thickness direction of the first wall portion, the projection of the first groove section, the projection of the second groove section, the projection of the second groove, and the projection of the extension line of the second groove together enclose the predetermined pressure relief area; Or In the thickness direction of the first wall portion, the projection of the first groove section, the projection of the extension line of the first groove section, the projection of the second groove section, the projection of the extension line of the second groove section, and the projection of the second groove together enclose the predetermined pressure relief area; Or In the thickness direction of the first wall portion, the projection of the first groove section, the projection of the extension line of the first groove section, the projection of the second groove section, the projection of the extension line of the second groove section, the projection of the second groove, and the projection of the extension line of the second groove together enclose the predetermined pressure relief area.

31. The battery cell according to any one of claims 1-28, wherein, The first groove includes a first groove section, a second groove section, and a third groove section. The second groove section and the third groove section are arranged oppositely. The first groove section connects the second groove section and the third groove section, and the first groove section is arranged oppositely to the second groove; In the thickness direction of the first wall portion, the projection of the first groove section, the projection of the second groove section, the projection of the third groove section, the projection of the second groove, and the projection of the extension line of the second groove together enclose the predetermined pressure relief area; Or In the thickness direction of the first wall portion, the projection of the first groove section, the projection of the second groove section, the projection of the extension line of the second groove section, the projection of the third groove section, the projection of the extension line of the third groove section, and the projection of the second groove together enclose the predetermined pressure relief area; Or In the thickness direction of the first wall portion, the projection of the first groove section, the projection of the second groove section, the projection of the extension line of the second groove section, the projection of the third groove section, the projection of the extension line of the third groove section, the projection of the second groove, and the projection of the extension line of the second groove together enclose the predetermined pressure relief area.

32. The battery cell according to claim 31, wherein, The connection position of the second groove section and the first groove section deviates from both ends of the second groove section, and the connection position of the third groove section and the first groove section deviates from both ends of the third groove section, so that the predetermined pressure relief areas are formed on both sides of the first groove section.

33. The battery cell according to claim 31 or 32, wherein The first groove section extends along a straight line or an arc track; and / or, the second groove section extends along a straight line or an arc track; and / or, the third groove section extends along a straight line or an arc track.

34. The battery cell according to any one of claims 1-33, wherein, The pressure relief component is integrally formed with the first wall portion.

35. The battery cell according to claim 34, wherein, The first groove is formed by stamping on the first wall portion; and / or, the second groove is formed by stamping on the first wall portion.

36. The battery cell according to any one of claims 1-33, wherein, The pressure relief component is separately provided from the first wall portion, and the pressure relief component is installed on the first wall portion.

37. The battery cell according to any one of claims 1-36, wherein, The first wall portion is a rectangular wall portion, and the first groove and the second groove are arranged along the width direction of the first wall portion.

38. The battery cell according to any one of claims 1-37, wherein, The housing includes: A housing body with an opening formed at at least one end; End caps corresponding to the openings one by one, and the end caps close the openings; Wherein, at least one of the end caps is the first wall portion; and / or, at least one wall portion of the housing is the first wall portion.

39. The battery cell according to claim 38, wherein, The opening is formed at only one end of the housing, and the wall portion of the housing opposite to the end cap is the first wall portion.

40. The battery cell according to claim 38, wherein, The openings are formed at both opposite ends of the housing, and at least one wall portion of the housing is the first wall portion.

41. The battery cell according to any one of claims 1 to 40, wherein, The material of the pressure relief component includes steel material.

42. The battery cell according to claim 41, wherein, The steel material is carbon steel or stainless steel.

43. The battery cell according to any one of claims 1-40, wherein, The material of the pressure relief component includes aluminum alloy.

44. The battery cell according to claim 43, wherein, The aluminum alloy includes the following components by mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, other single elements ≤ 0.03%.

45. The battery cell according to claim 43, wherein, The aluminum alloy includes the following components by mass percentage: 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%, total other element components ≤ 0.15%.

46. A battery, comprising a battery cell according to any one of claims 1 - 45.

47. An electrical device, comprising a battery cell according to any one of claims 1 - 45, and the battery cell is used to supply electrical energy to the electrical device.

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