WO2024103353A1

WO2024103353A1 - Casing component, battery cell, battery and electrical device

Info

Publication number: WO2024103353A1
Application number: PCT/CN2022/132661
Authority: WO
Inventors: 陈小波; 顾明光
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-11-17
Filing date: 2022-11-17
Publication date: 2024-05-23

Abstract

The embodiments of the present application belong to the technical field of batteries. Provided are a casing component, a battery cell, a battery and an electrical device. The casing component comprises a non-weak area and a weak area which are integrally formed, and is provided with a recess part. The non-weak area is formed around the recess part. The weak area is formed at the bottom of the recess part, and the weak area is configured to be damaged when a battery cell releases the internal pressure. The hardness of the weak area is H ₁, and the hardness of the non-weak area is H ₂, H ₁＞H ₂. The hardness of the weak area is greater than that of the non-weak area, and an increase of the hardness of the weak area improves the strength of the weak area, thereby reducing the risk of damaging the weak area during the normal use of the battery cell, and effectively prolonging the service life of the battery cell.

Description

Shell parts, battery cells, batteries and electrical equipment

Technical Field

The present application relates to the field of battery technology, and in particular to a housing component, a battery cell, a battery and an electrical device.

Background technique

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

In the development of battery technology, in addition to improving the safety of battery cells, the service life of battery cells is also an issue that needs to be considered. Therefore, how to improve the service life of battery cells is an urgent problem to be solved in battery technology.

Summary of the invention

The embodiments of the present application provide a housing component, a battery cell, a battery and an electrical device, which can effectively increase the service life of the battery.

In a first aspect, an embodiment of the present application provides a shell component for a battery cell, comprising an integrally formed non-weak area and a weak area, the shell component is provided with a groove, the non-weak area is formed around the groove, the weak area is formed at the bottom of the groove, and the weak area is configured to be destroyed when the battery cell releases internal pressure; wherein the hardness of the weak area is H ₁ , and the hardness of the non-weak area is H ₂ , satisfying: H ₁ >H ₂ .

In the above technical solution, the hardness of the weak area is greater than that of the non-weak area, which increases the hardness of the weak area, thereby increasing the strength of the weak area and reducing the risk of the weak area being damaged under normal use conditions of the battery cell, thereby effectively increasing the service life of the battery cell.

In some embodiments, H ₁ /H ₂ ≤5. If H ₁ /H ₂ is too large, the weak area may be difficult to be destroyed when the battery cell thermal runaways. Therefore, H ₁ /H ₂ ≤5 reduces the risk that the weak area cannot be destroyed in time when the battery cell thermal runaways, thereby improving the safety of the battery cell.

In some embodiments, H ₁ /H ₂ ≤2.5, which can further reduce the risk that the weak area cannot be destroyed in time when the battery cell has thermal runaway.

In some embodiments, 5HBW≤H ₁ ≤200HBW.

In some embodiments, 5HBW≤H ₂ ≤150HBW.

In some embodiments, the average grain size of the weak area is S ₁ , and the average grain size of the non-weak area is S ₂ , satisfying: S ₁ /S ₂ ≤ 0.9. The average grain size of the weak area is significantly different from the average grain size of the non-weak area, and reducing the average grain size of the weak area improves the mechanical properties of the material in the weak area, and improves the toughness and fatigue resistance of the weak area.

In some embodiments, S ₁ /S ₂ ≥ 0.05. If S ₁ /S ₂ is too small, the difficulty of forming the weak area increases, and if the strength of the weak area is too large, the difficulty of destroying the weak area during thermal runaway of the battery cell increases, and the pressure relief is prone to be delayed. Therefore, S ₁ /S ₂ ≥ 0.05 reduces the difficulty of forming the weak area and improves the timeliness of pressure relief of the battery cell during thermal runaway.

In some embodiments, 0.1≤S ₁ /S ₂ ≤0.5. This makes the overall performance of the housing component better, ensures that the weak area can be destroyed in time when the battery cell is in thermal runaway, and ensures that the weak area has sufficient strength during normal use of the battery cell.

In some embodiments, 0.4μm≤S ₁ ≤75μm. If S ₁ is too large, the toughness and fatigue resistance of the weak zone are poor; if S ₁ is too small, the molding of the weak zone is difficult, and the strength of the weak zone is too large, which increases the difficulty of destroying the weak zone during thermal runaway of the battery cell, and it is easy to cause untimely pressure relief. Therefore, 0.4μm≤S ₁ ≤75μm, on the one hand, reduces the difficulty of molding the weak zone and improves the timeliness of pressure relief of the battery cell during thermal runaway; on the other hand, it improves the toughness and fatigue resistance of the weak zone and reduces the risk of the weak zone being destroyed under normal use conditions of the battery cell.

In some embodiments, 1 μm ≤ S ₁ ≤ 10 μm. This makes the overall performance of the housing component better, ensures that the weak area can be destroyed in time when the battery cell is in thermal runaway, and ensures that the weak area has sufficient strength under normal use conditions of the battery cell.

In some embodiments, 10 μm ≤ _{S 2} ≤ 150 μm.

In some embodiments, 30 μm ≤ _{S 2} ≤ 100 μm.

In some embodiments, the minimum thickness of the weak zone is A, and the average grain size of the weak zone is S ₁ , which satisfies: 1≤A/S ₁ ≤100. If A/S ₁ is too small, the number of grain layers in the weak zone in the thickness direction of the weak zone is smaller, and the fatigue strength of the weak zone is too small; if A/S ₁ is too large, the number of grain layers in the weak zone in the thickness direction of the weak zone is too large, and the strength of the weak zone is too large, which may lead to the risk that the weak zone cannot be destroyed in time when the battery cell is in thermal runaway. Therefore, 1≤A/S ₁ ≤100, on the one hand, makes the number of grain layers in the weak zone in the thickness direction larger, improves the fatigue strength of the weak zone, and reduces the risk of the weak zone being destroyed under normal use conditions of the battery cell; on the other hand, makes the weak zone able to be destroyed more promptly when the battery cell is in thermal runaway, so as to achieve the purpose of timely pressure relief.

In some embodiments, 5≤A/S ₁ ≤20. This makes the overall performance of the housing component better, ensures that the weak area can be destroyed in time when the battery cell is in thermal runaway, ensures that the weak area has sufficient fatigue resistance under normal use conditions of the battery cell, and improves the service life of the battery cell.

In some embodiments, the minimum thickness of the weak area is A, which satisfies: 5HBW/mm≤H ₁ /A≤10000HBW/mm. Considering not only the influence of the thickness of the weak area on the performance of the shell component, but also the influence of the hardness of the weak area on the performance of the shell component, 5HBW/mm≤H ₁ /A≤10000HBW/mm can not only make the weak area have sufficient strength under normal use conditions of the battery cell, and the weak area is not easily damaged by fatigue, thereby improving the service life of the battery cell; but also can make the shell component release pressure through the weak area in time when the battery cell is thermally runaway, thereby reducing the risk of explosion of the battery cell and improving the safety of the battery cell.

In some embodiments, 190HBW/mm≤H ₁ /A≤4000HBW/mm. This makes the overall performance of the housing component better, ensures that the weak area can be destroyed in time when the battery cell is in thermal runaway, and ensures that the weak area has sufficient strength under normal use conditions of the battery cell. Under the premise of ensuring the safety of the battery cell, the service life of the battery cell is increased.

In some embodiments, the minimum thickness of the weak area is A, and the minimum thickness of the non-weak area is B, satisfying: 0.05≤A/B≤0.95. If A/B is too small, the strength of the weak area may be insufficient. If A/B is too large, the weak area may not be easily destroyed when the battery cell is in thermal runaway, and the pressure relief is not timely, resulting in an increased probability of battery cell explosion. Therefore, 0.05≤A/B≤0.95 can reduce the probability of the weak area rupturing under normal use conditions of the battery cell, and reduce the probability of explosion when the battery cell is in thermal runaway.

In some embodiments, 0.12≤A/B≤0.8. In this way, the comprehensive performance of the external components is better, and the weak area is ensured to have sufficient strength during normal use of the battery cell while ensuring that the weak area can be destroyed in time when the battery cell is in thermal runaway.

In some embodiments, 0.2≤A/B≤0.5. This further reduces the risk of the weak area being damaged under normal use conditions of the battery cell, ensures that the weak area is damaged in time when the battery cell is thermally runaway, and improves the timeliness of pressure relief.

In some embodiments, 1mm≤B≤5mm. If B is too large, the thickness of the non-weak area is large, more materials are used for the shell component, the weight of the shell component is large, and the economic efficiency is poor. If B is too small, the thickness of the non-weak area is small, and the anti-deformation ability of the shell component is poor. Therefore, 1mm≤B≤5mm makes the shell component have better economic efficiency and better anti-deformation ability.

In some embodiments, 1.2 mm ≤ B ≤ 3.5 mm, so that the housing component has better economy and anti-deformation ability.

In some embodiments, 2 mm ≤ B ≤ 3 mm.

In some embodiments, 0.02mm≤A≤1.6mm. If A is too small, the molding difficulty of the weak zone is difficult, and the weak zone is easily damaged during the molding process; if A is too large, the difficulty of destroying the weak zone during thermal runaway of the battery cell increases, and the pressure relief is likely to be delayed. Therefore, 0.02mm≤A≤1.6mm improves the timeliness of pressure relief of the battery cell during thermal runaway while reducing the molding difficulty of the pressure relief zone.

In some embodiments, 0.06 mm ≤ A ≤ 0.4 mm. This further reduces the difficulty of forming the pressure relief zone and improves the timeliness of pressure relief of the battery cell during thermal runaway.

In some embodiments, the housing component has a pressure relief area, the groove portion includes a primary notch groove, the notch groove is arranged along the edge of the pressure relief area, the pressure relief area is configured to be able to open with the notch groove as a boundary, and the weak area forms the bottom of the notch groove. When the weak area is destroyed, the pressure relief area can be opened with the weak area as a boundary to achieve pressure relief, thereby increasing the pressure relief area of the housing component.

In some embodiments, the housing component has a first surface and a second surface that are arranged opposite to each other, and the notched groove is recessed from the first surface toward the second surface. The notched groove is a groove portion, and the structure is simple. During molding, the notched groove can be molded on the first surface, which is simple to mold, improves production efficiency, and reduces production costs.

In some embodiments, the shell component includes a first surface and a second surface that are arranged opposite to each other, the groove portion includes a multi-level notch groove, the multi-level notch groove is sequentially arranged on the shell component along the direction from the first surface to the second surface, and the weak area is formed at the bottom of the first-level notch groove farthest from the first surface; wherein the shell component has a pressure relief area, each level of notch groove is arranged along the edge of the pressure relief area, and the pressure relief area is configured to be able to open with the first-level notch groove farthest from the first surface as a boundary. During molding, the multi-level notch groove can be molded step by step on the shell component, which can reduce the molding depth of each level of notch groove, thereby reducing the molding force on the shell component when molding each level of notch groove, reducing the risk of cracks in the shell component, and the shell component is not easy to fail due to cracks at the position where the notch groove is set, thereby increasing the service life of the shell component.

In some embodiments, the primary notch groove farthest from the second surface is recessed from the first surface toward the second surface. The groove portion is composed of multiple notches, and during molding, the multiple notches can be gradually processed from the first surface to the second surface.

In some embodiments, the shell component includes a first surface and a second surface that are arranged opposite to each other, and the groove portion further includes a primary groove, the groove is recessed from the first surface toward the second surface, and the pressure relief zone is formed on the bottom wall of the groove. The arrangement of the groove can reduce the depth of the notched groove while ensuring that the thickness of the final weak zone is constant, thereby reducing the forming force on the shell component when forming the notched groove and reducing the risk of cracks in the shell component. In addition, the groove can provide an escape space for the pressure relief zone during the opening process, and even if the first surface is blocked by an obstacle, the pressure relief zone can still be opened to relieve pressure.

In some embodiments, the shell component includes a first surface and a second surface that are arranged opposite to each other, and the groove portion also includes a multi-stage groove. The multi-stage groove is sequentially arranged on the shell component along the direction from the first surface to the second surface, and the first-stage groove farthest from the second surface is recessed from the first surface to the second surface, and the pressure relief zone is formed on the bottom wall of the first-stage groove farthest from the first surface. When forming the multi-stage groove, the forming depth of each stage of the groove can be reduced, and the forming force applied to the shell component when forming each stage of the groove can be reduced, thereby reducing the risk of cracks in the shell component. In addition, the multi-stage groove can provide an escape space for the pressure relief zone during the opening process, and even if the first surface is blocked by an obstacle, the pressure relief zone can still be opened to relieve pressure.

In some embodiments, the internal space of the sink is a cylinder, a prism, a truncated cone or a prism. The sink of this structure is simple in structure, easy to shape, and can provide more avoidance space for the pressure relief area during the opening process.

In some embodiments, the notched groove includes a first groove section and a second groove section, the first groove section intersects with the second groove section, and the first groove section and the second groove section are arranged along the edge of the pressure relief zone. The stress at the intersection of the first groove section and the second groove section is more concentrated, so that the weak area can be first destroyed at the intersection of the first groove section and the second groove section. When the detonation pressure of the battery cell is constant, the weak area can be made thicker to reduce the molding depth of the notched groove.

In some embodiments, the notched groove further includes a third groove section, the first groove section and the third groove section are arranged opposite to each other, the second groove section intersects with the third groove section, and the first groove section, the second groove section and the third groove section are arranged along the edge of the pressure relief zone. In this way, the pressure relief zone can be opened with the first groove section, the second groove section and the third groove section as the boundary, and when the battery cell is depressurized, the pressure relief zone is opened more easily, thereby realizing large-area pressure relief of the housing component.

In some embodiments, the first trough section, the second trough section and the third trough section are connected in sequence, and the first trough section, the second trough section and the third trough section define a pressure relief area.

In some embodiments, the first slot segment, the second slot segment and the third slot segment define two pressure relief areas, and the two pressure relief areas are respectively located on both sides of the second slot segment. The two pressure relief areas can be opened in a split form to relieve pressure, which can effectively improve the pressure relief efficiency of the housing component.

In some embodiments, the notched groove is a groove extending along a non-closed track. The pressure relief area can be opened in a flipping manner, and the pressure relief area is finally connected to other areas of the housing component after opening, reducing the risk of splashing after the pressure relief area is opened.

In some embodiments, the notched groove is an arc-shaped groove. The arc-shaped groove has a simple structure and is easy to form. During the pressure relief process, the pressure relief area can be quickly broken along the arc-shaped groove, so that the pressure relief area is quickly opened.

In some embodiments, the notched groove is a groove extending along a closed track. During the pressure relief process, the shell component can be broken along the notched groove, so that the pressure relief area can be opened in a disengaged manner, thereby increasing the pressure relief area of the shell component and improving the pressure relief rate of the shell component.

In some embodiments, the notched groove is an annular groove. The annular groove has a simple structure and is easy to form. During the pressure relief process, the shell component can be quickly broken along the annular groove to quickly open the pressure relief area.

In some embodiments, the area of the pressure relief zone is D, which satisfies: 90mm ² ≤D≤1500mm ² . If D is too small, the pressure relief area of the housing component is small, and the timeliness of pressure relief during thermal runaway of the battery cell is poor; if D is too large, the impact resistance of the pressure relief zone is poor, the deformation of the pressure relief zone after being stressed increases, and the weak area is easily damaged under normal use conditions of the battery cell, affecting the service life of the battery cell. Therefore, 90mm ² ≤D≤1500mm ² can not only improve the service life of the battery cell, but also improve the safety of the battery cell.

In some embodiments, 150 mm ² ≤ D ≤ 1200 mm ² .

In some embodiments, 200 mm ² ≤ D ≤ 1000 mm ² .

In some embodiments, 250 mm ² ≤ D ≤ 800 mm ² .

In some embodiments, the housing component has a first surface and a second surface that are arranged opposite to each other, the groove portion is recessed from the first surface toward the second surface, the groove portion forms an outer edge on the first surface, and the area of the housing component outside a preset distance from the outer edge is a non-weak area. In this way, the non-weak area is not easily affected by the process of forming the groove portion, so that the grains in the non-weak area are more uniform.

In some embodiments, the preset distance is L, satisfying: L=5 mm.

In some embodiments, the housing component further includes a transition zone, the transition zone connects the weak zone and the non-weak zone, the average grain size of the transition zone is S ₃ , and S ₃ ≤ S ₂ . The transition zone connects the weak zone and the non-weak zone to achieve integrated molding of the weak zone and the non-weak zone.

In some embodiments, the housing component is an end cap, which is used to close the opening of the housing, and the housing is used to accommodate the electrode assembly, so that the end cap has a pressure relief function to ensure the safety of the battery cell.

In some embodiments, the outer shell component is a shell having an opening, and the shell is used to accommodate the electrode assembly, so that the shell has a pressure relief function to ensure the safety of the battery cell.

In some embodiments, the housing includes a plurality of integrally formed walls, the plurality of walls together define an internal space of the housing, and at least one wall is provided with a groove. The plurality of walls are integrally formed so that the wall provided with the groove has better reliability.

In some embodiments, the multiple wall portions include a bottom wall and multiple side walls surrounding the bottom wall, and the shell forms an opening at an end opposite to the bottom wall; the bottom wall is provided with a groove portion; and/or at least one side wall is provided with a groove portion.

In some embodiments, the housing is a rectangular parallelepiped, which is suitable for square battery cells and can meet the large capacity requirements of battery cells.

In some embodiments, the material of the housing component includes aluminum alloy. The housing component of aluminum alloy is light in weight, has good ductility, and is easy to shape.

In some embodiments, the aluminum alloy includes the following components in mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%. This aluminum alloy has lower hardness, better forming ability, reduces the difficulty of forming the groove, improves the forming accuracy of the groove, and improves the pressure relief consistency of the shell components.

In some embodiments, the aluminum alloy includes the following components in percentage by mass: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single element components ≤ 0.05%, and other elements total components ≤ 0.15%. The housing parts made of such aluminum alloy have higher hardness, greater strength, and good anti-destruction ability.

In a second aspect, an embodiment of the present application provides a battery cell, comprising the housing component provided by any one embodiment of the first aspect.

In some embodiments, the battery cell further includes a shell having an opening, and the shell is used to accommodate the electrode assembly; the outer shell component is an end cover, and the end cover closes the opening.

In some embodiments, the housing component is a shell having an opening, and the shell is used to accommodate the electrode assembly; the battery cell also includes an end cover, which closes the opening.

In a third aspect, an embodiment of the present application provides a battery, comprising a battery cell provided by any embodiment of the second aspect.

In some embodiments, the weak area is located at the bottom of the battery cell. During the use of the battery, the weak area will be subjected to a large force under the gravity of the electrode assembly, electrolyte, etc. inside the battery cell. Since the weak area and the non-weak area are an integrated structure, it has good structural strength and better reliability, thereby increasing the service life of the battery cell.

In some embodiments, the battery cell includes a shell, which is used to accommodate an electrode assembly. The shell includes a bottom wall and multiple side walls surrounding the bottom wall. The bottom wall and the side walls are integrally formed. The shell forms an opening at one end opposite to the bottom wall, and the weak area is located on the bottom wall.

In some embodiments, the battery cell includes an end cover, which is used to close an opening of a shell, and the shell is used to accommodate the electrode assembly, and the weak area is located at the end cover.

In a fourth aspect, an embodiment of the present application provides an electrical device, comprising a battery provided by any embodiment of the third aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG1 is a schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

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

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

FIG4 is a schematic structural diagram of a housing component provided in some embodiments of the present application;

Fig. 5 is a C-C sectional view of the housing component shown in Fig. 4;

FIG6 is a grain map (schematic diagram) of the housing component shown in FIG5 ;

FIG7 is a partial enlarged view of the portion E of the housing component shown in FIG5 ;

FIG8 is a partial enlarged view of a housing component provided in some other embodiments of the present application;

FIG9 is a schematic structural diagram of a housing component provided in some other embodiments of the present application (showing a primary notch groove);

Fig. 10 is a cross-sectional view of the housing component taken along line E-E shown in Fig. 9;

FIG11 is a schematic structural diagram of a housing component provided in some other embodiments of the present application (showing a primary notch groove);

Fig. 12 is a cross-sectional view of the housing component taken along line F-F shown in Fig. 11;

FIG13 is a schematic structural diagram of a housing component provided in some other embodiments of the present application (showing a primary notch groove);

Fig. 14 is a G-G cross-sectional view of the housing component shown in Fig. 13;

FIG15 is a schematic structural diagram of a housing component provided in some other embodiments of the present application (showing two-level notch grooves);

Fig. 16 is a cross-sectional view of the housing component taken along line K-K shown in Fig. 15;

FIG17 is a schematic structural diagram of a housing component provided in some other embodiments of the present application (showing two-level notch grooves);

Fig. 18 is a cross-sectional view of the housing component taken along line M-M shown in Fig. 17;

FIG19 is a schematic structural diagram of a housing component provided in some other embodiments of the present application (showing two-level notch grooves);

Fig. 20 is a cross-sectional view of the housing component taken along line N-N shown in Fig. 19;

FIG21 is an isometric view of a housing component provided in some embodiments of the present application;

FIG22 is a schematic structural diagram of the housing component shown in FIG21 (showing a primary notch groove and a primary sink groove);

Fig. 23 is a cross-sectional view of the housing component taken along line O-O shown in Fig. 22;

FIG24 is a schematic structural diagram of a housing component provided in some other embodiments of the present application (showing a primary notch groove and a primary sink groove);

Fig. 25 is a P-P cross-sectional view of the housing component shown in Fig. 24;

FIG26 is a schematic structural diagram of a housing component provided in some other embodiments of the present application (showing a primary notch groove and a primary sink groove);

Fig. 27 is a Q-Q cross-sectional view of the housing component shown in Fig. 26;

FIG28 is a schematic diagram of the structure of a housing component provided in some embodiments of the present application (showing a primary scoring groove and a two-stage sinking groove);

Fig. 29 is a cross-sectional view of the housing component shown in Fig. 28 taken along line R-R;

FIG30 is a schematic structural diagram of a housing component provided in some other embodiments of the present application (showing a primary scoring groove and a two-stage sinking groove);

Fig. 31 is a S-S sectional view of the housing component shown in Fig. 30;

FIG32 is a schematic structural diagram of a housing component provided in some other embodiments of the present application (showing a primary notch groove and a two-stage sink groove);

Fig. 33 is a T-T cross-sectional view of the housing component shown in Fig. 32;

FIG34 is a schematic structural diagram of a housing component provided in some embodiments of the present application (showing a primary notch groove, which is V-shaped);

FIG35 is a schematic structural diagram of a housing component provided in another embodiment of the present application;

FIG36 is a grain map (schematic diagram) of a housing component provided in some other embodiments of the present application;

FIG37 is a schematic diagram of the structure of an end cap provided in some embodiments of the present application;

FIG38 is a schematic diagram of the structure of a housing provided in some embodiments of the present application;

FIG39 is a schematic diagram of the structure of a housing provided in some other embodiments of the present application;

FIG40 is a schematic diagram of the structure of a battery cell provided in some embodiments of the present application.

Icons: 1-housing; 11-end cap; 12-housing; 121-wall; 121a-side wall; 121b-bottom wall; 2-electrode assembly; 21-positive ear; 22-negative ear; 3-positive electrode terminal; 4-negative electrode terminal; 5-housing component; 51-non-weak area; 511-inner edge; 52-weak area; 53-groove; 531-bottom surface of the groove; 532-notched groove; 532a-outermost primary notched groove; 532b-innermost primary notched groove; 5321-first groove section ;5322-second slot section;5323-third slot section;533-sink;533a-outermost primary sink;533b-innermost primary sink;5331-bottom wall of the sink;534-outer edge;54-first surface;55-second surface;56-pressure relief zone;57-transition zone;10-battery cell;20-casing;201-first part;202-second part;100-battery;200-controller;300-motor;1000-vehicle;Y-midplane.

Detailed ways

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

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

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

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

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

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

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.

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

The battery mentioned in the embodiments of the present application may include one or more battery cells to provide a single physical module with higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in hybrid connection through a busbar component.

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.

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

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.

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

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

In a battery cell, to ensure the safety of the battery cell, a pressure relief mechanism may be provided on the outer shell of the battery cell. When the battery cell thermally runs away, the pressure inside the battery cell is released through the pressure relief mechanism to improve the safety of the battery cell.

For general battery cells, the pressure relief mechanism is welded to the outer shell to fix the pressure relief mechanism to the outer shell. Taking the pressure relief mechanism as an explosion-proof plate set on the end cover of the outer shell as an example, when the battery cell is in thermal runaway, the explosion-proof plate is destroyed to discharge the emissions inside the battery cell to achieve the purpose of releasing the pressure inside the battery cell. Since the pressure relief mechanism is welded to the outer shell, cracks may appear at the welding position during the long-term use of the battery cell, resulting in reduced strength at the welding position. It is easy for the welding position to be damaged when the pressure inside the battery cell does not reach the detonation pressure of the pressure relief mechanism, resulting in failure of the pressure relief mechanism and low reliability of the pressure relief mechanism.

In order to improve the reliability of the pressure relief mechanism, the inventors have found that the pressure relief mechanism and the housing can be set as an integral structure, that is, a part of the housing is used as the pressure relief mechanism. For example, a part of the end cover is weakened so that the strength of the part of the end cover is reduced to form a weak area, thereby forming an integrated pressure relief mechanism, which can effectively improve the reliability of the pressure relief mechanism.

The inventors noticed that after an integrated pressure relief mechanism is formed on the outer shell, the mechanical properties of the weak area of the outer shell are poor. Under normal use conditions of the battery cell, the weak area is prone to fatigue damage due to long-term changes in the internal pressure of the battery cell, affecting the service life of the battery cell.

In view of this, an embodiment of the present application provides a shell component, wherein a groove is provided on the shell component to form an integrally formed non-weak area and a weak area, wherein the non-weak area is formed around the groove, and the weak area is formed at the bottom of the groove. The hardness of the weak area is H ₁ , and the hardness of the non-weak area is H ₂ , satisfying: H ₁ >H ₂ .

In such a shell component, the hardness of the weak area is greater than that of the non-weak area, which increases the hardness of the weak area, thereby increasing the strength of the weak area, reducing the risk of the weak area being damaged under normal use conditions of the battery cell, and effectively increasing the service life of the battery cell.

The technical solutions described in the embodiments of the present application are applicable to batteries and electrical equipment using batteries.

Electrical equipment may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may be fuel vehicles, gas vehicles, or new energy vehicles, and new energy vehicles may 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.

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

Please refer to FIG. 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 inside the vehicle 1000, and the battery 100 can be disposed at the bottom, head, or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000, for example, the battery 100 can be used as an operating power source for the vehicle 1000.

The vehicle 1000 may further include a controller 200 and a motor 300 , wherein 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 starting, navigating, and driving the vehicle 1000 .

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

Please refer to FIG. 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 box 20 , wherein the box 20 is used to accommodate the battery cell 10 .

Among them, the box body 20 is a component for accommodating the battery cell 10, and the box body 20 provides a placement space for the battery cell 10. The box body 20 can adopt a variety of structures. In some embodiments, the box body 20 may include a first part 201 and a second part 202, and the first part 201 and the second part 202 cover each other to define a placement space for accommodating the battery cell 10. The first part 201 and the second part 202 may be in a variety of shapes, such as a cuboid, a cylinder, etc. The first part 201 may be a hollow structure with one side open, and the second part 202 may also be a hollow structure with one side open, and the open side of the second part 202 covers the open side of the first part 201, so as to form a box body 20 with a placement space. It is also possible that the first part 201 is a hollow structure with one side open, and the second part 202 is a plate-like structure, and the second part 202 covers the open side of the first part 201, so as to form a box body 20 with a placement space. As an example, the battery cell 10 can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell 10 of other shapes. The prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery, etc. There is no special limitation in the present application.

In the battery 100, there may be one or more battery cells 10. If there are more than one battery cell 10, the battery cells 10 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the battery cells 10 are both connected in series and in parallel. The battery modules may be formed by connecting the battery cells 10 in series, in parallel, or in a mixed connection, and then the battery modules may be formed into a whole by connecting the battery cells 10 in series, in parallel, or in a mixed connection, and then accommodated in the box 20. Alternatively, all the battery cells 10 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by all the battery cells 10 may be accommodated in the box 20.

Please refer to FIG3 , 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 .

The housing 1 is used to accommodate the electrode assembly 2 and the electrolyte and other components. The housing 1 can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell) or an aluminum-plastic film, etc. As an example, the housing 1 can include a shell 12 and an end cap 11.

The shell 12 may be a hollow structure with an opening at one end, or a hollow structure with openings at two opposite ends. The shell 12 may be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, and the like.

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

In the battery cell 10, there may be one or two end caps 11. In the embodiment where the shell 12 is a hollow structure with openings at both ends, two end caps 11 may be provided, and the two end caps 11 respectively close the two openings of the shell 12, and the two end caps 11 and the shell 12 together define a storage space. In the embodiment where the shell 12 is a hollow structure with an opening at one end, there may be one end cap 11 provided, and the end cap 11 closes the opening at one end of the shell 12, and the one end cap 11 and the shell 12 together define a storage space.

The electrode assembly 2 includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell 10, active ions (such as lithium ions) are inserted and removed between the positive electrode and the negative electrode. The separator is arranged between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting, while allowing the active ions to pass through.

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

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

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 or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc., treated with silver surface, may be used. The composite current collector may include a polymer material base and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO ₄ (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO ₄ ), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as _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 LiNi1 _/ _3Co1 _/ _3Mn1 _/ _3O2 (also referred _to as _NCM333 ), _{LiNi0.5Co0.2Mn0.3O2} (also referred to as _NCM523 ₎ , _{LiNi0.5Co0.25Mn0.25O2} (also _referred _to as _NCM211 ₎ , _{LiNi0.6Co0.2Mn0.2O2} (also referred _to as _NCM622 ), _{LiNi0.8Co0.1Mn0.1O2} ( _also referred to _as _NCM811 ), lithium _nickel cobalt aluminum oxide ( _such as LiNi _0.85 Co _0.15 Al _0.05 O ₂ ) and at least one of their modified compounds.

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

In some embodiments, the negative electrode may be a negative electrode sheet, and 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.

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

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

As an example, the negative electrode active material may adopt the negative electrode active material for the battery 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 and 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.

In some embodiments, the negative electrode may be a foam metal. The foam metal may be foam nickel, foam copper, foam aluminum, foam alloy, or foam carbon, etc. When the foam metal is used as the negative electrode sheet, the surface of the foam metal may not be provided with a negative electrode active material, but of course, a negative electrode active material may also be provided.

As an example, the negative electrode current collector may be filled with or/and deposited with a lithium source material, potassium metal or sodium metal, where the lithium source material is lithium metal and/or a lithium-rich material.

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.

In some embodiments, the electrode assembly 2 further includes a separator, which is disposed between the positive electrode and the negative electrode.

In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without special restrictions. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without special restrictions. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surface of the positive and negative electrodes.

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

In some embodiments, the battery cell 10 further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The present application has no specific restrictions on the type of electrolyte, which can be selected according to needs. The electrolyte can be liquid, gel or solid.

The liquid electrolyte includes an electrolyte salt and a solvent.

In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent can also be selected from ether solvents. Ether solvents can 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.

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

Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

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

As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphide, germanium argentum sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

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

In some embodiments, the electrode assembly 2 is a wound structure. The positive electrode sheet and the negative electrode sheet are wound into a wound structure.

In some embodiments, the electrode assembly 2 is a laminate structure.

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

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.

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

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

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

In some embodiments, the shape of the electrode assembly 2 can be cylindrical, flat, or polygonal.

In some embodiments, the electrode assembly 2 is provided with tabs, which can lead current out of the electrode assembly 2. The tabs include a positive tab 21 and a negative tab 22.

The battery cell 10 may further include an electrode terminal, which may be disposed on the housing 1 and is used to electrically connect to the tab of the electrode assembly 2 to output the electrical energy of the battery cell 10. The electrode terminal and the tab may be directly connected, for example, the electrode terminal and the tab are directly welded. The electrode terminal and the tab may also be indirectly connected, for example, the electrode terminal and the tab are indirectly connected through a current collecting member. The current collecting member may be a metal conductor, for example, copper, iron, aluminum, steel, aluminum alloy, etc.

As shown in FIG. 3 , taking the shell 12 as an example of a hollow structure with an opening at one end, two electrode terminals can be provided on the end cover 11 , and the two electrode terminals are respectively a positive electrode terminal 3 and a negative electrode terminal 4 , the positive electrode terminal 3 is electrically connected to the positive electrode ear 21 , and the negative electrode terminal 4 is electrically connected to the negative electrode ear 22 .

Please refer to Figures 4 and 5, Figure 4 is a schematic diagram of the structure of a shell component 5 provided in some embodiments of the present application; Figure 5 is a CC cross-sectional view of the shell component 5 shown in Figure 4. The present application embodiment provides a shell component 5 for a battery cell 10, comprising an integrally formed non-weak area 51 and a weak area 52, the shell component 5 is provided with a groove 53, the non-weak area 51 is formed around the groove 53, the weak area 52 is formed at the bottom of the groove 53, and the weak area 52 is configured to be destroyed when the battery cell 10 releases internal pressure; wherein the hardness of the weak area 52 is H ₁ , and the hardness of the non-weak area 51 is H ₂ , satisfying: H ₁ >H ₂ .

The shell component 5 is a component that can accommodate the electrode assembly 2 together with other components. The shell component 5 is a part of the shell 1. The end cap 11 of the shell 1 can be the shell component 5, and the shell 12 of the shell 1 can be the shell component 5. The shell component 5 can be made of metal, such as copper, iron, aluminum, steel, aluminum alloy, etc., and the shell component 5 can be an aluminum-plastic film.

The weak area 52 is a portion of the outer shell component 5 that is weaker than other areas. When the internal pressure of the battery cell 10 reaches a threshold value, the weak area 52 of the outer shell component 5 can be destroyed to release the pressure inside the battery cell 10. The weak area 52 can be destroyed by rupture, detachment, etc. For example, when the internal pressure of the battery cell 10 reaches a threshold value, the weak area 52 ruptures under the action of the emissions (gas, electrolyte, etc.) inside the battery cell 10, so that the emissions inside the battery cell 10 can be discharged smoothly. The weak area 52 can be in a variety of shapes, such as rectangular, circular, elliptical, annular, arc-shaped, U-shaped, H-shaped, etc. The thickness of the weak area 52 can be uniform or uneven.

The weak area 52 is formed at the bottom of the groove 53. The groove 53 can be formed in a variety of ways. For example, the groove 53 can be formed by stamping, milling, laser etching, etc., so as to realize the integral molding of the weak area 52 and the non-weak area 51. After the groove 53 is stamped on the shell component 5, the shell component 5 is thinned in the area where the groove 53 is set, and the weak area 52 is formed accordingly. The groove 53 can be a primary groove, and the groove side of the groove 53 is continuous along the depth direction of the groove 53. For example, the groove 53 is a groove whose internal space is a rectangular parallelepiped, a columnar body, etc. The groove 53 can also be a multi-level groove, and the multi-level grooves are arranged along the depth direction of the groove 53. In the adjacent two-level grooves, the inner (deeper position) primary groove is set on the groove bottom surface of the outer (shallower position) primary groove. For example, the groove 53 is a stepped groove. During the forming process, the multi-stage grooves can be formed by stamping step by step along the depth direction of the groove portion 53 , and the weak area 52 is formed at the bottom of the first-stage groove located at the deepest position (innermost) among the multi-stage grooves.

The non-weak area 51 is formed around the groove 53, and the strength of the non-weak area 51 is greater than that of the weak area 52. The weak area 52 is more easily damaged than the non-weak area 51. When the groove 53 is formed on the shell component 5 by stamping, the non-weak area 51 can be a portion of the shell component 5 that is not stamped. The thickness of the non-weak area 51 can be uniform or non-uniform.

The hardness of the weak area 52 and the hardness of the non-weak area 51 are Brinell hardness, in units of HBW. The Brinell hardness measurement method can be implemented by referring to the measurement principle in GB/T23.1-2018. In the actual measurement process, the hardness of the weak area 52 can be measured on the inner surface or outer surface in the thickness direction of the weak area 52; the hardness of the non-weak area 51 can be measured on the inner surface or outer surface in the thickness direction of the non-weak area 51. Taking the shell component 5 as the end cover 11 of the battery cell 10 as an example, the hardness of the weak area 52 can be measured on the outer surface of the weak area 52 away from the inside of the battery cell 10, or on the inner surface of the weak area 52 facing the inside of the battery cell 10. The hardness of the non-weak area 51 can be measured on the outer surface of the non-weak area 51 away from the inside of the battery cell 10, or on the inner surface of the non-weak area 51 facing the inside of the battery cell 10.

In FIG. 5 , the thickness direction of the weak area 52 is consistent with the thickness direction of the non-weak area 51 , both of which are in the Z direction.

In the embodiment of the present application, the weak area 52 and the non-weak area 51 are integrally formed, and the reliability of the housing component 5 is higher. The hardness of the weak area 52 is greater than the hardness of the non-weak area 51, which increases the hardness of the weak area 52, thereby increasing the strength of the weak area 52, reducing the risk of the weak area 52 being damaged under normal use conditions of the battery cell 10, and can effectively increase the service life of the battery cell 10.

In some embodiments, H ₁ /H ₂ ≤5.

H ₁ /H ₂ can be any one of 1.1, 1.5, 2, 2.5, 3, 3.5, 3.6, 4, 4.5, 5, or a range of values between any two of them.

When H ₁ /H ₂ >5, the hardness of the weak area 52 may be too large, and the weak area 52 may be difficult to be destroyed when the battery cell 10 thermally runs away.

If H ₁ /H ₂ is too large, the weak area 52 may be difficult to be destroyed when the battery cell 10 experiences thermal runaway.

Therefore, H ₁ /H ₂ ≤5, which reduces the risk that the weak area 52 cannot be destroyed in time when the battery cell 10 is in thermal runaway, thereby improving the safety of the battery cell 10 .

In some embodiments, H ₁ /H ₂ ≤ 2.5.

H ₁ /H ₂ can be any one of 1.1, 1.11, 1.12, 1.2, 1.25, 1.3, 1.4, 1.5, 1.6, 1.7, 1.71, 1.72, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5 or a range between any two of them.

In this embodiment, H ₁ /H ₂ ≤2.5, which can further reduce the risk that the weak area 52 cannot be destroyed in time when the battery cell 10 has thermal runaway.

In some embodiments, 5HBW≤H ₁ ≤200HBW.

_H1 can be any one of 5HBW, 6HBW, 8HBW, 10HBW, 15HBW, 19HBW, 20HBW, 30HBW, 32HBW, 44HBW, 50HBW, 60HBW, 70HBW, 80HBW, 90HBW, 100HBW, 110HBW, 120HBW, 130HBW, 140HBW, 150HBW, 160HBW, 170HBW, 180HBW, 190HBW, and 200HBW, or a range between any two of them.

In some embodiments, 5HBW≤H ₂ ≤150HBW.

_H2 can be any one of 5HBW, 8HBW, 9HBW, 9.5HBW, 10HBW, 15HBW, 16HBW, 19HBW, 20HBW, 30HBW, 40HBW, 50HBW, 52HBW, 52.5HBW, 53HBW, 60HBW, 70HBW, 80HBW, 90HBW, 100HBW, 110HBW, 120HBW, 130HBW, 140HBW, and 150HBW, or a range between any two of them.

In some embodiments, please refer to FIG6 , which is a grain map (schematic diagram) of the housing component 5 shown in FIG5 . The average grain size of the weak area 52 is S ₁ , and the average grain size of the non-weak area 51 is S ₂ , satisfying: S ₁ /S ₂ ≤0.9.

The method for measuring the average grain size can refer to the intercept method in GB 6394-2017, which will not be described in detail here. When measuring the average grain size of the weak area 52, the measurement can be performed along the thickness direction of the weak area 52; when measuring the average grain size of the non-weak area 51, the measurement can be performed along the thickness direction of the non-weak area 51.

S ₁ /S ₂ can be any one of 0.01, 0.03, 0.04, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9 or a range between any two of them.

In this embodiment, S ₁ /S ₂ ≤0.9, and the average grain size of the weak area 52 is significantly different from the average grain size of the non-weak area 51 . The average grain size of the weak area 52 is reduced, the mechanical properties of the material of the weak area 52 are improved, the toughness and fatigue resistance of the weak area 52 are improved, the risk of the weak area 52 being damaged under normal use conditions of the battery cell 10 is reduced, and the service life of the battery cell 10 is increased.

In some embodiments, S ₁ /S ₂ ≥ 0.05.

The inventors have noticed that when S ₁ /S ₂ <0.05, the difficulty of forming the weak area 52 increases, and the strength of the weak area 52 is too large, making it more difficult for the weak area 52 to be destroyed when the battery cell 10 thermally runs away, and the pressure relief is likely to be delayed.

Therefore, S ₁ /S ₂ ≥0.05, which reduces the difficulty of molding the molded weak area 52 and improves the timeliness of pressure release of the battery cell 10 during thermal runaway.

In some embodiments, 0.1≤S ₁ /S ₂ ≤0.5.

S ₁ /S ₂ can be any one of 0.1, 0.12, 0.15, 0.17, 0.2, 0.22, 0.25, 0.27, 0.3, 0.32, 0.35, 0.37, 0.4, 0.42, 0.45, 0.47, 0.5, or a range between any two of them.

In this embodiment, 0.1≤S ₁ /S ₂ ≤0.5, so that the overall performance of the housing component 5 is better, and the weak area 52 can be destroyed in time when the battery cell 10 is in thermal runaway, and the weak area 52 has sufficient strength during normal use of the battery cell 10.

In some embodiments, 0.4 μm ≤ _{S 1} ≤ 75 μm.

S ₁ can be any point value among 0.4μm, 0.5μm, 1μm, 2μm, 3μm, 4μm, 5μm, 10μm, 15μm, 16μm, 20μm, 25μm, 28μm, 30μm, 35μm, 36μm, 40μm, 45μm, 49μm, 50μm, 55μm, 56μm, 60μm, 65μm, 70μm, 72μm, 75μm, or any range value between any two of them.

The inventors noticed that when S ₁ > 75 μm, the toughness and fatigue resistance of the weak area 52 are poor; when S ₁ < 0.4 mm, the weak area 52 is difficult to form and the strength of the weak area 52 is too large, making it more difficult for the weak area 52 to be destroyed when the battery cell 10 thermally runs away, and untimely pressure relief is likely to occur.

Therefore, 0.4 μm≤S ₁ ≤75 μm, on the one hand, reduces the difficulty of forming the weak area 52 and improves the timeliness of pressure relief of the battery cell 10 during thermal runaway; on the other hand, improves the toughness and fatigue resistance of the weak area 52 and reduces the risk of the weak area 52 being damaged under normal use conditions of the battery cell 10.

In some embodiments, 1 μm ≤ S ₁ ≤ 10 μm.

S ₁ can be any point value among 1μm, 1.5μm, 1.6μm, 1.7μm, 2μm, 2.5μm, 2.6μm, 3μm, 3.2μm, 3.3μm, 3.5μm, 3.6μm, 4μm, 4.5μm, 4.6μm, 5μm, 5.5μm, 5.6μm, 6μm, 6.5μm, 6.6μm, 7μm, 7.5μm, 7.6μm, 8μm, 8.5μm, 8.6μm, 9μm, 9.5μm, 9.6μm, 10μm, or any range value between any two of them.

In this embodiment, 1 μm≤S ₁ ≤10 μm, so that the overall performance of the housing component 5 is better, and the weak area 52 can be destroyed in time when the battery cell 10 is thermally runaway, and the weak area 52 has sufficient strength under normal use conditions of the battery cell 10.

In some embodiments, 10 μm ≤ _{S 2} ≤ 150 μm.

S ₂ can be any point value among 10μm, 15μm, 20μm, 25μm, 30μm, 32μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm, 150μm, or any range value between any two of them.

In some embodiments, 30 μm ≤ _{S 2} ≤ 100 μm.

S ₂ can be any point value among 30μm, 32μm, 35μm, 37μm, 40μm, 42μm, 45μm, 47μm, 50μm, 52μm, 55μm, 57μm, 60μm, 62μm, 65μm, 67μm, 70μm, 72μm, 75μm, 77μm, 80μm, 82μm, 85μm, 87μm, 90μm, 92μm, 95μm, 97μm, 100μm, or any range value between any two of them.

In some embodiments, the minimum thickness of the weak region 52 is A, and the average grain size of the weak region 52 is S ₁ , satisfying: 1≤A/S ₁ ≤100.

A/S ₁ can be any point value among 1, 1.3, 2, 3, 3.1, 3.2, 4, 5, 10, 15, 20, 21, 22, 23, 25, 30, 31, 33, 34, 35, 37, 38, 40, 45, 50, 55, 60, 65, 63, 70, 75, 80, 85, 90, 93, 94, 95, 100 or any range between two of them.

When A/S ₁ ＜1, in the thickness direction of the weak zone 52, the number of grain layers in the weak zone 52 is smaller, and the fatigue strength of the weak zone 52 is too small; when A/S ₁ ＞100, in the thickness direction of the weak zone 52, the number of grain layers in the weak zone 52 is too large, and the strength of the weak zone 52 is too large, which easily leads to the risk that the weak zone 52 cannot be destroyed in time when the battery cell 10 has thermal runaway.

Therefore, 1≤A/S ₁ ≤100. On the one hand, the number of grain layers in the thickness direction of the weak area 52 is large, the fatigue strength of the weak area 52 is improved, and the risk of the weak area 52 being damaged under normal use conditions of the battery cell 10 is reduced; on the other hand, the weak area 52 can be damaged more promptly when the battery cell 10 thermally runs away, so as to achieve the purpose of timely pressure relief.

In some embodiments, 5≤A/S ₁ ≤20.

A/S ₁ can be any one of 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20 or a range between any two of them.

In this embodiment, 5≤A/S ₁ ≤20, so that the comprehensive performance of the shell component 5 is better, and the weak area 52 can be destroyed in time when the battery cell 10 is thermally runaway, and the weak area 52 has sufficient fatigue resistance under normal use conditions of the battery cell 10, thereby improving the service life of the battery cell 10.

In some embodiments, the minimum thickness of the weak area 52 is A, which satisfies: 5HBW/mm≤H ₁ /A≤10000HBW/mm.

_H1 /A may be 5HBW/mm, 6HBW/mm, 7HBW/mm, 20HBW/mm, 50HBW/mm, 61HBW/mm, 62HBW/mm, 63HBW/mm, 64HBW/mm, 65HBW/mm, 66HBW/mm, 67HBW/mm, 75HBW/mm, 80HBW/mm, 90HBW/mm, 100HBW/mm, 120HBW/mm, 128HBW/mm, 1 Any one of 50HBW/mm, 160HBW/mm, 190HBW/mm, 500HBW/mm, 1000HBW/mm, 1200HBW/mm, 1750HBW/mm, 1800HBW/mm, 2100HBW/mm, 4000HBW/mm, 5000HBW/mm, 8000HBW/mm, 9000HBW/mm, 10000HBW/mm or the range between any two of them.

When H ₁ /A＞10000HBW/mm, the weak area 52 is thinner and has a higher hardness, which makes the weak area 52 very thin and brittle, and the weak area 52 is easily damaged under normal use conditions of the battery cell 10, and the service life of the battery cell 10 is short. When H ₁ /A＜5HBW/mm, the weak area 52 is thicker and has a lower hardness. When the battery cell 10 thermally runs away, the weak area 52 will be stretched and extended, and the timeliness of pressure relief is poor.

In this embodiment, not only the influence of the thickness of the weak area 52 on the performance of the shell component 5 is taken into consideration, but also the influence of the hardness of the weak area 52 on the performance of the shell component 5 is taken into consideration, 5HBW/mm≤H ₁ /A≤10000HBW/mm, which can not only ensure that the weak area 52 has sufficient strength under normal use conditions of the battery cell 10, and the weak area 52 is not easily damaged due to fatigue, thereby improving the service life of the battery cell 10; but also enable the shell component 5 to release pressure in time through the weak area 52 when the battery cell 10 is thermally runaway, thereby reducing the risk of explosion of the battery cell 10 and improving the safety of the battery cell 10.

In some embodiments, 190 HBW/mm≤H ₁ /A≤4000 HBW/mm.

_H1 /A may be 190HBW/mm, 200HBW/mm, 220HBW/mm, 250HBW/mm, 280HBW/mm, 300HBW/mm, 320HBW/mm, 350HBW/mm, 400HBW/mm, 450HBW/mm, 500HBW/mm, 533HBW/mm, 600HBW/mm, 700HBW/mm, 800HBW/mm, 875HBW/mm, Any one of 1000HBW/mm, 1200HBW/mm, 1280HBW/mm, 1500HBW/mm, 1600HBW/mm, 1750HBW/mm, 1800HBW/mm, 2000HBW/mm, 2100HBW/mm, 2500HBW/mm, 3000HBW/mm, 3500HBW/mm, and 4000HBW/mm, or the range between any two of them.

In this embodiment, 190HBW/mm≤H ₁ /A≤4000HBW/mm, so that the overall performance of the housing component 5 is better, and the weak area 52 can be destroyed in time when the battery cell 10 is in thermal runaway, and the weak area 52 has sufficient strength under normal use conditions of the battery cell 10. Under the premise of ensuring the safety of the battery cell 10, the service life of the battery cell 10 is improved.

In some embodiments, please refer to Figures 7 and 8, Figure 7 is a partial enlarged view of the E portion of the housing component 5 shown in Figure 5; Figure 8 is a partial enlarged view of the housing component 5 provided in some other embodiments of the present application. The minimum thickness of the weak area 52 is A, and the minimum thickness of the non-weak area 51 is B, satisfying: 0.05≤A/B≤0.95.

A/B can be any point value among 0.05, 0.06, 0.07, 0.08, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.8, 0.85, 0.9, 0.95 or any range between two of them.

The minimum thickness of the weak area 52 is the thickness at the thinnest position of the weak area 52. The minimum thickness of the non-weak area 51 is the thickness at the thinnest position of the non-weak area 51.

As an example, as shown in Figures 7 and 8, the shell component 5 has a first surface 54 and a second surface 55 that are arranged opposite to each other, the groove portion 53 is recessed from the first surface 54 toward the second surface 55, and the portion of the shell component 5 located between the groove bottom surface 531 of the groove portion and the second surface 55 is a weak area 52.

The first surface 54 and the second surface 55 can be arranged in parallel or at a small angle. If the first surface 54 and the second surface 55 are arranged at a small angle, for example, the angle between the two is within 10 degrees, the minimum distance between the first surface 54 and the second surface 55 is the minimum thickness of the non-weak area 51; as shown in Figures 7 and 8, if the first surface 54 and the second surface 55 are parallel, the distance between the first surface 54 and the second surface 55 is the minimum thickness of the non-weak area 51.

The groove bottom surface 531 of the groove portion can be a plane or a curved surface. If the groove bottom surface 531 of the groove portion is a plane, the groove bottom surface 531 of the groove portion and the second surface 55 can be parallel or set at a small angle. If the groove bottom surface 531 of the groove portion and the second surface 55 are set at a small angle, for example, the angle between the two is within 10 degrees, the minimum distance between the groove bottom surface 531 of the groove portion and the second surface 55 is the minimum thickness of the weak area 52; as shown in FIG7, if the groove bottom surface 531 of the groove portion is parallel to the second surface 55, the distance between the groove bottom surface 531 of the groove portion and the second surface 55 is the minimum thickness of the weak area 52. As shown in FIG8, if the groove bottom surface 531 of the groove portion is a curved surface, for example, the groove bottom surface 531 of the groove portion is an arc surface, the minimum distance between the groove bottom surface 531 of the groove portion and the second surface 55 is the minimum thickness of the weak area 52.

When A/B＜0.05, the weak area 52 may be insufficient in strength, and the probability of the weak area 52 rupturing under normal use conditions of the battery cell 10 increases. When A/B＞0.95, the weak area 52 may not be easily destroyed when the battery cell 10 thermally runs away, and the pressure relief is not timely, resulting in an increased probability of the battery cell 10 exploding.

Therefore, 0.05≤A/B≤0.95 can reduce the probability of the weak area 52 being broken under normal use conditions of the battery cell 10 and the probability of the battery cell 10 exploding when thermal runaway occurs.

In some embodiments, 0.12≤A/B≤0.8.

A/B can be any one of 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.2, 0.22, 0.25, 0.27, 0.3, 0.32, 0.35, 0.37, 0.4, 0.42, 0.45, 0.47, 0.5, 0.52, 0.55, 0.57, 0.6, 0.62, 0.65, 0.66, 0.67, 0.7, 0.72, 0.75, 0.77, 0.8 or a range between any two of them.

In this embodiment, 0.12≤A/B≤0.8, so that the comprehensive performance of the external components is better, and the weak area 52 is ensured to have sufficient strength during normal use of the battery cell 10 while ensuring that the weak area 52 can be destroyed in time when the battery cell 10 has thermal runaway.

In some embodiments, 0.2≤A/B≤0.5.

A/B can be any one of 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.5 or a range between any two of them.

In this embodiment, 0.2≤A/B≤0.5, which further reduces the risk of the weak area 52 being damaged under normal use conditions of the battery cell 10 and ensures that the weak area 52 is damaged in time when the battery cell 10 has thermal runaway, thereby improving the timeliness of pressure relief.

In some embodiments, 1 mm ≤ B ≤ 5 mm.

B can be any point value among 1mm, 2mm, 3mm, 4mm, 5mm, or a range value between any two of them.

When B>5mm, the thickness of the non-weak area 51 is large, the shell component 5 uses more materials, the shell component 5 is heavy, and the economy is poor. When B<1mm, the thickness of the non-weak area 51 is small, and the shell component 5 has poor anti-deformation ability.

Therefore, 1mm≤B≤5mm, so that the housing component 5 has better economy and better anti-deformation ability.

In some embodiments, 1.2 mm ≤ B ≤ 3.5 mm.

B can be any point value among 1.2mm, 1.25mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, or a range value between any two of them.

In this embodiment, 1.2 mm ≤ B ≤ 3.5 mm, so that the housing component 5 has better economy and anti-deformation ability.

In some embodiments, 2 mm ≤ B ≤ 3 mm.

In some embodiments, 0.02 mm ≤ A ≤ 1.6 mm.

A can be 0.02mm, 0.04mm, 0.05mm, 0.06mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.62mm, 0.63mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 0.96mm, 0.97mm, 0.98mm, 0.99mm, 0.10mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.20mm, 0.21mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.30mm, 0.31mm, 0.32mm, 0.33mm, 0.34mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.40mm, 0.41mm, 0.4 Any point value among mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.18mm, 1.19mm, 1.2mm, 1.22mm, 1.23mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.42mm, 1.43mm, 1.45mm, 1.47mm, 1.5mm, 1.55mm, 1.6mm or the range value between any two of them.

When A is less than 0.02 mm, the weak area 52 is difficult to form, and the weak area 52 is easily damaged during the forming process; when A is greater than 1.6 mm, the weak area 52 is more difficult to be destroyed when the battery cell 10 has thermal runaway, and the pressure relief is likely to be untimely.

Therefore, 0.02 mm ≤ A ≤ 1.6 mm, while reducing the difficulty of forming the pressure relief area 56 , the timeliness of the pressure relief of the battery cell 10 during thermal runaway is improved.

In some embodiments, 0.06 mm ≤ A ≤ 0.4 mm.

A can be any point value among 0.06mm, 0.07mm, 0.08mm, 0.1mm, 0.15mm, 0.18mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, or a range value between any two of them.

In this embodiment, 0.06 mm≤A≤0.4 mm, which further reduces the difficulty of forming the pressure relief area 56 and improves the timeliness of pressure relief of the battery cell 10 during thermal runaway.

In some embodiments, please refer to FIG9-FIG14, FIG9 is a schematic diagram of the structure of the shell component 5 provided in some other embodiments of the present application (showing the primary notch groove 532); FIG10 is an E-E cross-sectional view of the shell component 5 shown in FIG9; FIG11 is a schematic diagram of the structure of the shell component 5 provided in some other embodiments of the present application (showing the primary notch groove 532); FIG12 is an F-F cross-sectional view of the shell component 5 shown in FIG11; FIG13 is a schematic diagram of the structure of the shell component 5 provided in some other embodiments of the present application (showing the primary notch groove 532); FIG14 is a G-G cross-sectional view of the shell component 5 shown in FIG13. The shell component 5 has a pressure relief area 56, and the groove portion 53 includes a primary notch groove 532, and the notch groove 532 is arranged along the edge of the pressure relief area 56, and the pressure relief area 56 is configured to be able to be opened with the notch groove 532 as the boundary, and the weak area 52 forms the bottom of the notch groove 532.

The pressure relief area 56 is an area of the outer shell component 5 that can be opened after the weak area 52 is damaged. For example, when the pressure inside the battery cell 10 reaches a threshold, the weak area 52 is cracked, and the pressure relief area 56 is opened outward under the action of the discharge inside the battery cell 10. In this process, the weak area 52 is cracked along the notched groove 532, and the pressure relief area 56 is opened, so that the pressure relief area 56 is opened with the notched groove 532 as the boundary. After the pressure relief area 56 is opened, the outer shell component 5 can form a discharge port at a position corresponding to the pressure relief area 56, and the discharge inside the battery cell 10 can be discharged through the discharge port to release the pressure inside the battery cell 10.

The notched groove 532 can be formed in the housing component 5 in a variety of ways, such as stamping, milling, laser etching, etc. The notched groove 532 in the groove portion 53 is only one level, and the first-level notched groove 532 can be formed by one stamping. The notched groove 532 can be a groove of various shapes, such as an annular groove, an arc groove, a U-shaped groove, an H-shaped groove, etc. The weak area 52 is formed at the bottom of the notched groove 532, and the shape of the weak area 52 is the same as the shape of the notched groove 532. For example, the weak area 52 is a U-shaped groove, and the weak area 52 extends along the U-shaped track.

As an example, the maximum width of the notch groove 532 is X, where X≤10 mm. The width of the notch groove 532 at its widest position is the maximum width of the notch groove 532 .

In this embodiment, the weak area 52 forms the bottom of the notch groove 532 . When the weak area 52 is destroyed, the pressure relief area 56 can be opened with the weak area 52 as the boundary to achieve pressure relief, thereby increasing the pressure relief area of the shell component 5 .

In some embodiments, please continue to refer to FIG. 10 , FIG. 12 and FIG. 14 , the housing component 5 has a first surface 54 and a second surface 55 that are oppositely disposed, and the notched groove 532 is recessed from the first surface 54 toward the direction close to the second surface 55 .

The first surface 54 may be the inner surface of the shell component 5 facing the inside of the battery cell 10, and the second surface 55 may be the outer surface of the shell component 5 away from the inside of the battery cell 10; or the first surface 54 may be the outer surface of the shell component 5 away from the inside of the battery cell 10, and the second surface 55 may be the inner surface of the shell component 5 facing the inside of the battery cell 10. As an example, the first surface 54 is parallel to the second surface 55, and the minimum thickness of the non-weak area 51 is the distance between the first surface 54 and the second surface 55.

The groove bottom surface of the notched groove 532 is the groove bottom surface 531 of the groove portion. The portion of the housing component 5 between the groove bottom surface of the notched groove 532 and the second surface 55 is the groove bottom wall of the notched groove 532, and the groove bottom wall of the notched groove 532 is the weak area 52.

In this embodiment, the groove portion 53 only includes a primary notch groove 532, and the notch groove 532 is the groove portion 53. The groove portion 53 is a primary groove with a simple structure. During molding, the notch groove 532 can be molded on the first surface 54, which is simple to mold, improves production efficiency, and reduces production costs.

In some embodiments, please refer to Figures 15 to 20, Figure 15 is a schematic diagram of the structure of the shell component 5 provided in some other embodiments of the present application (showing the two-stage notch groove 532); Figure 16 is a K-K cross-sectional view of the shell component 5 shown in Figure 15; Figure 17 is a schematic diagram of the structure of the shell component 5 provided in some other embodiments of the present application (showing the two-stage notch groove 532); Figure 18 is an M-M cross-sectional view of the shell component 5 shown in Figure 17; Figure 19 is a schematic diagram of the structure of the shell component 5 provided in some other embodiments of the present application (showing the two-stage notch groove 532); Figure 20 is an N-N cross-sectional view of the shell component 5 shown in Figure 19. The shell component 5 includes a first surface 54 and a second surface 55 arranged oppositely, and the groove portion 53 includes a multi-stage notch groove 532, which is sequentially arranged on the shell component 5 along the direction from the first surface 54 to the second surface 55, and the weak area 52 is formed at the bottom of the first-stage notch groove 532 farthest from the first surface 54. The housing component 5 has a pressure relief zone 56 , each level of notched groove 532 is arranged along the edge of the pressure relief zone 56 , and the pressure relief zone 56 is configured to be able to open with the first level notched groove 532 farthest from the first surface 54 as a boundary.

The groove portion 53 includes a multi-stage notched groove 532. It is understandable that the groove portion 53 is a multi-stage groove. Each stage of the notched groove 532 is arranged along the edge of the pressure relief zone 56. It is understandable that the multi-stage notched groove 532 is arranged around the pressure relief zone 56, so that the extension direction of the multi-stage notched groove 532 is basically the same, so that the shape of the multi-stage notched groove 532 is basically the same. The notched groove 532 in the groove portion 53 can be two-stage, three-stage, four-stage or more. Each stage of the notched groove 532 can be formed on the shell component 5 by stamping. During the molding, the notched groove 532 of each stage can be stamped and formed in sequence along the direction from the first surface 54 to the second surface 55. When stamping and forming the multi-stage notched groove 532, the multi-stage notched groove 532 can be formed by multiple stampings, and each stamping forms a stage of notched groove 532. The notched groove 532 can be a groove of various shapes, such as an annular groove, an arc groove, a U-shaped groove, an H-shaped groove, etc.

The pressure relief area 56 is an area of the housing component 5 that can be opened after the weak area 52 is damaged. The primary notch 532 farthest from the first surface 54 is located at the edge of the pressure relief area 56. During the opening process of the pressure relief area 56, the weak area 52 is split along the primary notch 532 farthest from the first surface 54, so that the pressure relief area 56 is opened with the primary notch 532 farthest from the first surface 54 as the boundary.

The weak area 52 is formed at the bottom of the primary notch groove 532 farthest from the first surface 54, and the primary notch groove 532 farthest from the first surface 54 is the primary notch groove 532 at the deepest position (innermost). Among the two adjacent notch grooves 532, the primary notch groove 532 farthest from the first surface 54 is arranged at the bottom surface of the primary notch groove 532 close to the first surface 54. The portion of the housing component 5 between the groove bottom surface of the primary notch groove 532 farthest from the first surface 54 and the second surface 55 is the groove bottom wall of the primary notch groove 532 farthest from the first surface 54, and the groove bottom wall is the weak area 52. The groove bottom surface of the primary notch groove 532 farthest from the first surface 54 is the groove bottom surface 531 of the groove portion. The primary scoring groove 532 farthest from the first surface 54 is the innermost primary scoring groove 532b, and the primary scoring groove 532 closest to the first surface 54 is the outermost primary scoring groove 532a.

As an example, the maximum width of the outermost primary notch groove 532a is X, where X≤10 mm. The width of the outermost primary notch groove 532a at the widest position is the maximum width of the outermost primary notch groove 532a.

During molding, multiple levels of notched grooves 532 can be formed step by step on the shell component 5, and the molding depth of each level of notched groove 532 can be reduced, thereby reducing the molding force applied to the shell component 5 when molding each level of notched groove 532, reducing the risk of cracks in the shell component 5, and making it less likely for the shell component 5 to fail due to cracks at the location where the notched groove 532 is set, thereby increasing the service life of the shell component 5.

In some embodiments, referring to FIG. 16 , FIG. 18 , and FIG. 20 , the primary notch groove 532 farthest from the second surface 55 is recessed from the first surface 54 toward the direction close to the second surface 55 .

Taking the notched groove 532 in the groove portion 53 as an example, the two-level notched groove 532 is a first-level notched groove and a second-level notched groove. The first-level notched groove is arranged on the first surface 54, that is, the first-level notched groove is recessed from the first surface 54 toward the direction close to the second surface 55, and the second-level notched groove is arranged on the groove bottom surface of the first-level notched groove; that is, the second-level notched groove is recessed from the groove bottom surface of the first-level notched groove toward the direction close to the second surface 55. The first-level notched groove is the outermost first-level notched groove 532a, and the second-level notched groove is the innermost first-level notched groove 532b.

The groove portion 53 is composed of a multi-stage notched groove 532 . During molding, the multi-stage notched groove 532 can be gradually machined from the first surface 54 to the second surface 55 , and the molding efficiency is high.

In some embodiments, please refer to Figures 21 to 27, Figure 21 is an isometric view of the housing component 5 provided in some embodiments of the present application; Figure 22 is a structural schematic diagram of the housing component 5 shown in Figure 21 (showing the primary notch groove 532 and the primary sink groove 533); Figure 23 is an O-O cross-sectional view of the housing component 5 shown in Figure 22; Figure 24 is a structural schematic diagram of the housing component 5 provided in some other embodiments of the present application (showing the primary notch groove 532 and the primary sink groove 533); Figure 25 is a P-P cross-sectional view of the housing component 5 shown in Figure 24; Figure 26 is a structural schematic diagram of the housing component 5 provided in some other embodiments of the present application (showing the primary notch groove 532 and the primary sink groove 533); Figure 27 is a Q-Q cross-sectional view of the housing component 5 shown in Figure 26. The housing component 5 includes a first surface 54 and a second surface 55 arranged opposite to each other, and the groove portion 53 also includes a primary sink groove 533, the sink groove 533 is recessed from the first surface 54 to the direction close to the second surface 55, and the pressure relief area 56 is formed on the bottom wall 5331 of the sink groove.

It should be noted that, no matter whether the notched groove 532 in the groove portion 53 is one-stage or multi-stage, the groove portion 53 may include a one-stage sink groove 533. It is understandable that the groove portion 53 has both the notched groove 532 and the sink groove 533, and the groove portion 53 is a multi-stage groove. The sink groove 533 and the notched groove 532 are arranged along the direction from the first surface 54 to the second surface 55. During molding, the sink groove 533 can be molded on the shell component 5 first, and then the notched groove 532 can be molded on the bottom wall 5331 of the sink groove. The sink groove 533 can be molded on the shell component 5 in a variety of ways, such as stamping molding, milling molding, laser etching molding, etc.

The bottom wall 5331 of the sink is the portion of the housing component 5 located below the bottom surface of the sink 533. After the sink 533 is formed on the first surface 54, the remaining portion of the housing component 5 in the area where the sink 533 is set is the bottom wall 5331 of the sink. As shown in Figures 23, 25, and 27, the portion of the housing component 5 located between the bottom surface of the sink 533 and the second surface 55 is the bottom wall 5331 of the sink. The pressure relief area 56 may be a portion of the bottom wall 5331 of the sink.

The arrangement of the recessed groove 533 can reduce the depth of the notched groove 532 while ensuring that the thickness of the final weak area 52 is constant, thereby reducing the forming force on the shell component 5 when forming the notched groove 532, and reducing the risk of cracks on the shell component 5. In addition, the recessed groove 533 can provide an escape space for the pressure relief area 56 during the opening process, and even if the first surface 54 is blocked by an obstacle, the pressure relief area 56 can still be opened to relieve pressure.

In some embodiments, please refer to Figures 28-33, Figure 28 is a structural schematic diagram of the shell component 5 provided in some embodiments of the present application (showing the primary notch groove 532 and the two-stage sink groove 533); Figure 29 is an R-R cross-sectional view of the shell component 5 shown in Figure 28; Figure 30 is a structural schematic diagram of the shell component 5 provided in some other embodiments of the present application (showing the primary notch groove 532 and the two-stage sink groove 533); Figure 31 is an S-S cross-sectional view of the shell component 5 shown in Figure 30; Figure 32 is a structural schematic diagram of the shell component 5 provided in other embodiments of the present application (showing the primary notch groove 532 and the two-stage sink groove 533); Figure 33 is a T-T cross-sectional view of the shell component 5 shown in Figure 32. The shell component 5 includes a first surface 54 and a second surface 55 that are arranged opposite to each other, and the groove portion 53 also includes a multi-stage groove 533. The multi-stage groove 533 is sequentially arranged on the shell component 5 along the direction from the first surface 54 to the second surface 55. The first-stage groove 533 farthest from the second surface 55 is recessed from the first surface 54 to the second surface 55, and the pressure relief area 56 is formed on the groove bottom wall 5331 of the first-stage groove farthest from the first surface 54.

It should be noted that, whether the notched groove 532 in the groove portion 53 is one-stage or multi-stage, the groove portion 53 may include multi-stage sink grooves 533. It is understandable that the groove portion 53 has both the notched groove 532 and the sink groove 533, and the groove portion 53 is a multi-stage groove. The sink groove 533 and the notched groove 532 are arranged along the direction from the first surface 54 to the second surface 55. During molding, the multi-stage sink groove 533 may be molded on the housing component 5 first, and then the notched groove 532 may be molded on the groove bottom wall 5331 of the first-stage sink groove farthest from the first surface 54.

The first-level sink groove 533 farthest from the second surface 55 (closest to the first surface 54) is the outermost first-level sink groove 533a, and the first-level sink groove 533 farthest from the first surface 54 is the innermost first-level sink groove 533b. The outermost first-level sink groove 533a is disposed on the first surface 54, and the outermost first-level sink groove 533a is recessed from the first surface 54 to the second surface 55.

The groove bottom wall 5331 of the primary groove farthest from the first surface 54 is the portion of the shell component 5 below the groove bottom surface of the primary groove 533 farthest from the first surface 54. After the multi-stage groove 533 is formed on the shell component 5, the remaining portion of the shell component 5 in the area where the primary groove 533 farthest from the first surface 54 is set is the groove bottom wall 5331 of the groove. As shown in Figures 29, 31, and 33, the portion of the shell component 5 between the groove bottom surface of the primary groove 533 farthest from the first surface 54 and the second surface 55 is the groove bottom wall 5331 of the primary groove farthest from the first surface 54. Among them, the pressure relief area 56 can be a part of the groove bottom wall 5331 of the primary groove farthest from the first surface 54.

The sink grooves 533 in the groove portion 53 may be two-level, three-level, four-level or more. In the adjacent two-level sink grooves 533, the first-level sink groove 533 away from the first surface 54 is arranged on the bottom surface of the first-level sink groove 533 close to the first surface 54. Along the direction from the first surface 54 to the second surface 55, the contour of the bottom surface of the multi-level sink groove 533 decreases step by step. The sink grooves 533 of each level can be formed on the shell component 5 in a variety of ways, such as stamping, milling, laser etching, etc. Taking the example of the sink grooves 533 of each level being formed on the shell component 5 by stamping, during the forming, the sink grooves 533 of each level can be stamped out in sequence along the direction from the first surface 54 to the second surface 55, and then the notched grooves 532 can be stamped. Taking the case where the groove 533 in the groove portion 53 is two-stage and the notched groove 532 is one-stage as an example, during stamping, two stampings may be performed first to form two-stage grooves 533, and then one stamping may be performed to form one-stage notched groove 532. As an example, in FIGS. 28-33 , the groove 533 in the groove portion 53 is two-stage.

When forming the multi-stage groove 533, the forming depth of each stage of the groove 533 can be reduced, and the forming force applied to the shell component 5 when forming each stage of the groove 533 can be reduced, thereby reducing the risk of cracks in the shell component 5. In addition, the multi-stage groove 533 can provide an escape space for the pressure relief zone 56 during the opening process, so that even if the first surface 54 is blocked by an obstacle, the pressure relief zone 56 can still be opened to relieve pressure.

In some embodiments, the internal space of the sink 533 is a cylinder, a prism, a frustum or a prism.

The internal space of the sink 533 is the space defined by the side surface and the bottom surface of the sink 533. The prism body can be a triangular prism, a quadrangular prism, a pentagonal prism, a hexagonal prism, etc.; the pyramid body can be a triangular pyramid, a quadrangular pyramid, a pentagonal pyramid, or a hexagonal pyramid, etc. As an example, in Figures 21-33, the internal space of the groove 53 is a quadrangular prism, and specifically, the internal space of the groove 53 is a cuboid.

In this embodiment, the sink 533 has a simple structure and is easy to form, and can provide more avoidance space for the pressure relief area 56 during the opening process.

In some embodiments, please refer to FIG. 34 , which is a schematic diagram of the structure of the housing component 5 provided in some embodiments of the present application (showing a primary notch groove 532 , which is V-shaped). The notch groove 532 includes a first groove section 5321 and a second groove section 5322 , the first groove section 5321 intersects with the second groove section 5322 , and the first groove section 5321 and the second groove section 5322 are arranged along the edge of the pressure relief area 56 .

The first slot section 5321 and the second slot section 5322 may be straight slots or non-straight slots, such as arc slots. In the embodiment where the first slot section 5321 and the second slot section 5322 are both straight slots, it is understandable that the first slot section 5321 and the second slot section 5322 both extend along a straight line, and the first slot section 5321 and the second slot section 5322 may be arranged at an acute angle, a right angle or an obtuse angle. The first slot section 5321 and the second slot section 5322 may be arranged crosswise, such as the intersection of the first slot section 5321 and the second slot section 5322 is located at the midpoint of the first slot section 5321 and the midpoint of the second slot section 5322; as shown in FIG. 34, the intersection of the first slot section 5321 and the second slot section 5322 may also be located at one end of the first slot section 5321 and one end of the second slot section 5322, the first slot section 5321 and the second slot section 5322 constitute a V-shaped structure, and the notched groove 532 is V-shaped.

In this embodiment, the stress at the intersection of the first groove section 5321 and the second groove section 5322 is more concentrated, so that the weak area 52 can be first destroyed at the intersection of the first groove section 5321 and the second groove section 5322. When the detonation pressure of the battery cell 10 is constant, the weak area 52 can be made thicker to reduce the molding depth of the notch groove 532.

In some embodiments, please refer to Figures 9, 15, 22 and 28, the notched groove 532 can also include a third groove section 5323, the first groove section 5321 and the third groove section 5323 are arranged opposite to each other, the second groove section 5322 intersects with the third groove section 5323, and the first groove section 5321, the second groove section 5322 and the third groove section 5323 are arranged along the edge of the pressure relief zone 56.

The first slot section 5321, the second slot section 5322 and the third slot section 5323 can all be straight slots, or non-straight slots, such as arc slots. In the embodiment where the first slot section 5321, the second slot section 5322 and the third slot section 5323 are all straight slots, it is understandable that the first slot section 5321, the second slot section 5322 and the third slot section 5323 all extend along a straight line, and the first slot section 5321 and the third slot section 5323 can be arranged in parallel or at an angle. The first slot section 5321 and the third slot section 5323 can be perpendicular to the second slot section 5322 or not perpendicular to the second slot section 5322.

The connection position between the second slot segment 5322 and the first slot segment 5321 can be located at one end of the first slot segment 5321, or at a position deviated from one end of the first slot segment 5321, for example, the connection position between the second slot segment 5322 and the first slot segment 5321 is located at the midpoint of the first slot segment 5321 in the extension direction; the connection position between the second slot segment 5322 and the third slot segment 5323 can be located at one end of the third slot segment 5323, or at a position deviated from one end of the third slot segment 5323, for example, the connection position between the second slot segment 5322 and the third slot segment 5323 is located at the midpoint of the third slot segment 5323 in the extension direction.

It should be noted that, in the embodiment where the groove portion 53 includes a multi-level notched groove 532, it can be understood that, in two adjacent levels of notched grooves 532, the first groove section 5321 of the first-level notched groove 532 away from the first surface 54 is arranged at the groove bottom surface of the first groove section 5321 of the first-level notched groove 532 close to the first surface 54; the second groove section 5322 of the first-level notched groove 532 away from the first surface 54 is arranged at the groove bottom surface of the second groove section 5322 of the first-level notched groove 532 close to the first surface 54; and the third groove section 5323 of the first-level notched groove 532 away from the first surface 54 is arranged at the groove bottom surface of the third groove section 5323 of the first-level notched groove 532 close to the first surface 54.

In this embodiment, the pressure relief zone 56 can be opened with the first groove section 5321 , the second groove section 5322 and the third groove section 5323 as boundaries. When the battery cell 10 is depressurized, the pressure relief zone 56 is opened more easily, thereby achieving large-area pressure relief of the housing component 5 .

In some embodiments, please continue to refer to Figures 9, 15, 22 and 28. The first slot segment 5321, the second slot segment 5322 and the third slot segment 5323 define two pressure relief areas 56, and the two pressure relief areas 56 are respectively located on both sides of the second slot segment 5322.

As an example, the first slot section 5321, the second slot section 5322 and the third slot section 5323 form an H-shaped notched slot 532, the connection position of the second slot section 5322 and the first slot section 5321 is located at the midpoint of the first slot section 5321, and the connection position of the third slot section 5323 and the second slot section 5322 is located at the midpoint of the third slot section 5323. The two pressure relief areas 56 are symmetrically arranged on both sides of the second slot section 5322, and it can be understood that the areas of the two pressure relief areas 56 are equal. In other embodiments, the two pressure relief zones 56 may also be asymmetrically arranged on both sides of the second slot section 5322, so that the areas of the two pressure relief zones 56 are not equal. For example, the first slot section 5321 and the third slot section 5323 are both perpendicular to the second slot section 5322, the connection position between the second slot section 5322 and the first slot section 5321 deviates from the midpoint of the first slot section 5321, and/or the connection position between the third slot section 5323 and the second slot section 5322 is located at the midpoint of the third slot section 5323.

The two pressure relief zones 56 are respectively located on both sides of the second groove section 5322, so that the two pressure relief zones 56 are divided by the second groove section 5322. After the shell component 5 is ruptured at the position of the second groove section 5322, the two pressure relief zones 56 can be opened in a split form along the first groove section 5321 and the third groove section 5323 to achieve pressure relief, which can effectively improve the pressure relief efficiency of the shell component 5.

In other embodiments, the first slot segment 5321 , the second slot segment 5322 , and the third slot segment 5323 are connected in sequence, and the first slot segment 5321 , the second slot segment 5322 , and the third slot segment 5323 define a pressure relief zone 56 .

The first groove section 5321 , the second groove section 5322 and the third groove section 5323 are sequentially connected to form a U-shaped notched groove 532 .

In some embodiments, the score groove 532 is a groove extending along a non-closed trajectory.

A non-closed track refers to a track whose two ends are not connected in the extension direction. The non-closed track can be an arc track, a U-shaped track, etc.

In this embodiment, the notched groove 532 is a groove along a non-closed trajectory, and the pressure relief area 56 can be opened in a flipping manner. After the pressure relief area 56 is opened, it is finally connected to other areas of the shell component 5, reducing the risk of splashing after the pressure relief area 56 is opened.

In some embodiments, referring to FIG. 11 , FIG. 17 , FIG. 24 and FIG. 30 , the notched groove 532 is an arc-shaped groove.

The arc-shaped groove is a groove extending along an arc-shaped trajectory, and the arc-shaped trajectory is a non-closed trajectory. The center angle of the arc-shaped groove can be less than, equal to or greater than 180°.

The arc-shaped groove has a simple structure and is easy to form. During the pressure relief process, the pressure relief area 56 can be quickly broken along the arc-shaped groove so that the pressure relief area 56 is quickly opened.

In some embodiments, referring to FIG. 13 , FIG. 19 , FIG. 26 , and FIG. 32 , the notched groove 532 is a groove extending along a closed track.

A closed trajectory refers to a trajectory that is connected at both ends. A closed trajectory can be a circular trajectory, a rectangular trajectory, etc.

During the pressure relief process, the shell component 5 can rupture along the notched groove 532 , so that the pressure relief area 56 can be opened in a detached manner, thereby increasing the pressure relief area of the shell component 5 and improving the pressure relief rate of the shell component 5 .

In some embodiments, the score groove 532 is an annular groove.

The annular groove may be a rectangular annular groove or a circular annular groove.

The annular groove has a simple structure and is easy to form. During the pressure relief process, the shell component 5 can be quickly ruptured along the annular groove to allow the pressure relief area 56 to open quickly.

In some embodiments, the area of the pressure relief zone 56 is D, which satisfies: 90 mm ² ≤ D ≤ 1500 mm ² .

In FIGS. 9 , 11 , 13 , 15 , 17 , 19 , 22 , 24 , 26 , 28 , 30 , 32 and 34 , the area of the shaded portion is the area of the pressure relief zone 56 .

It should be noted that in the embodiment where the groove portion 53 includes multiple levels of notched grooves 532 , the area of the pressure relief zone 56 is the area of the region defined by the deepest (innermost) level one notched groove 532 .

D can be ^90mm2 , ^95mm2 , ^100mm2 , 150mm2, ^200mm2 ^, 250mm2 ^, ^300mm2 ^, 350mm2, ^400mm2 , 450mm2 ^, 500mm2 ^, 550mm2 ^, ^600mm2 ^, ^650mm2 ^, 700mm2 ^, 750mm2 ^, ^800mm2 , ^900mm2 , ^950mm2 , 1000mm2, 1050mm2, ^1100mm2 , 1150mm2, ^1200mm2 , ^1250mm2 , ^1300mm2 , ^1350mm2 , ^1400mm2 , ^1450mm2 , ^1500mm2 Any point value in ² or any range between them.

When D is less than 90 mm ² , the pressure relief area of the housing component 5 is small, and the timeliness of pressure relief when the battery cell 10 is in thermal runaway is poor; when D is greater than 1500 mm ² , the impact resistance of the pressure relief area 56 is poor, the deformation of the pressure relief area 56 increases after being stressed, and the weak area 52 is easily damaged under normal use conditions of the battery cell 10, affecting the service life of the battery cell 10. Therefore, 90 mm ² ≤ D ≤ 1500 mm ² can not only improve the service life of the battery cell 10, but also improve the safety of the battery cell 10.

Furthermore, 150 mm ² ≤D≤1200 mm ² . This makes the overall performance of the outer shell component 5 better, and makes the outer shell component 5 have a larger pressure relief area and better impact resistance.

Further, 200 mm ² ≤D ≤ 1000 mm ² .

Further, 250 mm ² ≤D ≤ 800 mm ² .

In some embodiments, referring to FIGS. 4 to 34 , the housing component 5 has a first surface 54 and a second surface 55 that are oppositely disposed, the groove 53 is recessed from the first surface 54 toward the second surface 55, the groove 53 forms an outer edge 534 on the first surface 54, and the area of the housing component 5 outside the preset distance from the outer edge 534 is the non-weak area 51. The preset distance is L.

L can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc.

In the embodiment shown in FIGS. 9 to 14 , the groove portion 53 includes only a primary notched groove 532, the notched groove 532 is disposed on the first surface 54, the groove side surface of the notched groove 532 intersects with the first surface 54 to form an outer edge 534, and the groove side surface of the notched groove 532 is disposed around the groove bottom surface of the notched groove 532. It should be noted that in the embodiment shown in FIG. 13 , since the notched groove 532 is a groove extending along a closed trajectory, the groove side surface of the notched groove 532 intersects with the first surface 54 to form an inner ring line and an outer ring line located outside the inner ring line, and the outer ring line is the outer edge 534.

In the embodiment shown in FIGS. 15 to 20 , the groove portion 53 only includes the multi-stage notched groove 532, the outermost first-stage notched groove 532a is arranged on the first surface 54, and the groove side surface of the outermost first-stage notched groove 532a intersects with the first surface 54 to form an outer edge 534. It should be noted that in the embodiment shown in FIG. 19 , since the notched groove 532 is a groove extending along a closed trajectory, the outermost first-stage notched groove 532a intersects with the first surface 54 to form an inner ring line and an outer ring line located outside the inner ring line, and the outer ring line is the outer edge 534.

In the embodiment shown in FIGS. 21 to 27 , the groove portion 53 further includes a primary groove 533, the groove 533 is disposed on the first surface 54, the groove side surface of the groove 533 intersects with the first surface 54 to form an outer edge 534, and the groove side surface of the groove 533 is arranged around the groove bottom surface of the groove 533. In the embodiment shown in FIGS. 28 to 33 , the groove portion 53 further includes a multi-stage groove 533, the outermost primary groove 533a is disposed on the first surface 54, and the groove side surface of the outermost primary groove 533a intersects with the first surface 54 to form an outer edge 534.

It can be understood that the distance between the outer edge 534 and the inner edge 511 of the non-weak area 51 is a preset distance L, and the shape of the inner edge 511 of the non-weak area 51 can be substantially the same as the shape of the outer edge 534. The direction of the preset distance L can be perpendicular to the thickness direction of the non-weak area 51, that is, the preset distance L can be measured along the thickness direction perpendicular to the non-weak area 51. When measuring the average grain size of the non-weak area 51, the measurement can be performed in the area outside the outer edge 534.

In this embodiment, the area of the shell component 5 beyond the preset distance from the outer edge 534 is the non-weak area 51. The non-weak area 51 is a certain distance away from the groove portion 53. The non-weak area 51 is not easily affected by the process of forming the groove portion 53, so that the grains of the non-weak area 51 are more uniform.

In some embodiments, L = 5 mm.

It should be noted that, as shown in FIG9 and FIG15, in the embodiment where the first groove section 5321 and the third groove section 5323 of the notched groove 532 are arranged opposite to each other, taking the first groove section 5321 and the third groove section 5323 being parallel as an example, when the spacing between the first groove section 5321 and the third groove section 5323 is greater than 2*L, the inner edge 511 of the non-weak area 51 is partially located in the pressure relief area 56, so that the pressure relief area 56 is partially located in the non-weak area 51. In other embodiments, please refer to FIG35, which is a schematic diagram of the structure of the housing component 5 provided in other embodiments of the present application. When the spacing between the first groove section 5321 and the third groove section 5323 is less than or equal to 2*L, the inner edge 511 of the non-weak area 51 is not located in the pressure relief area 56, and the inner edge 511 of the non-weak area 51 is roughly rectangular. Along the width direction of the first slot segment 5321, the distance between the first slot segment 5321 and the inner edge 511 of the non-weakened area 51 is L; along the length direction of the first slot segment 5321, the distance between the first slot segment 5321 and the inner edge 511 of the non-weakened area 51 is L; along the width direction of the third slot segment 5323, the distance between the third slot segment 5323 and the inner edge 511 of the non-weakened area 51 is L; along the length direction of the third slot segment 5323, the distance between the third slot segment 5323 and the inner edge 511 of the non-weakened area 51 is L.

In some embodiments, please refer to FIG36, which is a grain map (schematic diagram) of the shell component 5 provided in some other embodiments of the present application. The shell component 5 also includes a transition zone 57, which connects the weak zone 52 and the non-weak zone 51. The average grain size of the transition zone 57 is _S3 , _satisfying : _S3≤S2 .

As an example, S ₃ >S ₁ .

The transition zone 57 is the portion of the shell component 5 connecting the weak zone 52 and the non-weak zone 51. The transition zone 57 is arranged around the outside of the weak zone 52, and the non-weak zone 51 is arranged around the outside of the transition zone 57. The weak zone 52, the transition zone 57 and the non-weak zone 51 are formed as one piece.

The average grain size of the transition zone 57 may gradually decrease from the non-weak zone 51 to the weak zone 52. As an example, as shown in FIG36 , taking the case where the groove portion 53 includes a primary sink groove 533 and a primary notch groove 532, the average grain size of the transition zone 57 located outside the sink groove 533 may be greater than the average grain size of the transition zone 57 located at the bottom of the sink groove 533, the average grain size of the transition zone 57 located outside the sink groove 533 may be less than or equal to the average grain size S ₂ of the non-weak zone 51, and the average grain size of the transition zone 57 located at the bottom of the sink groove 533 may be greater than the average grain size S ₁ of the weak zone 52.

In this embodiment, the transition area 57 serves to connect the weak area 52 and the non-weak area 51 , so that the weak area 52 and the non-weak area 51 are integrally formed.

In some embodiments, please refer to FIG. 37 , which is a schematic diagram of the structure of the end cap 11 provided in some embodiments of the present application. The housing component 5 is the end cap 11 , which is used to close the opening of the shell 12 , and the shell 12 is used to accommodate the electrode assembly 2 .

It can be understood that the end cap 11 is provided with a groove portion 53 to form a corresponding weak area 52 and a non-weak area 51. The first surface 54 and the second surface 55 of the housing component 5 are two surfaces opposite to each other in the thickness direction of the end cap 11, that is, one of the first surface 54 and the second surface 55 is the inner surface of the end cap 11 in the thickness direction, and the other is the outer surface of the end cap 11 in the thickness direction.

The end cover 11 may be a circular or rectangular plate-shaped structure.

As an example, in the embodiment shown in FIG. 37 , the end cover 11 is a rectangular plate-like structure.

In this embodiment, the end cover 11 has a pressure relief function to ensure the safety of the battery cell 10 .

In some embodiments, please refer to Figures 38 and 39, Figure 38 is a schematic diagram of the structure of the shell 12 provided in some embodiments of the present application; Figure 39 is a schematic diagram of the structure of the shell 12 provided in other embodiments of the present application. The outer shell component 5 is the shell 12, and the shell 12 has an opening, and the shell 12 is used to accommodate the electrode assembly 2.

In this embodiment, the shell 12 of the housing 1 is the housing component 5, and the end cover 11 of the housing 1 is used to close the opening of the shell 12. The shell 12 can be a hollow structure with an opening formed at one end, or a hollow structure with openings formed at two opposite ends. The shell 12 can be a cuboid, a cylinder, etc.

In this embodiment, the outer shell component 5 is a shell 12 , so that the shell 12 has a pressure relief function to ensure the safety of the battery cell 10 .

In some embodiments, the housing 12 includes a plurality of integrally formed wall portions 121 , the plurality of wall portions 121 together define an internal space of the housing 12 , and at least one of the wall portions 121 is provided with a groove portion 53 .

In the housing 12, the groove 53 may be provided on one wall 121 to form an integrally formed weak area 52 and a non-weak area 51 on the wall 121; or the grooves 53 may be provided on a plurality of walls 121 to form an integrally formed weak area 52 and a non-weak area 51 on each wall 121 provided with the groove 53. For the wall 121 provided with the groove 53, the first surface 54 and the second surface 55 of the housing component 5 are two surfaces opposite to each other in the thickness direction of the wall 121, that is, one of the first surface 54 and the second surface 55 is the inner surface of the wall 121 in the thickness direction, and the other is the outer surface of the wall 121 in the thickness direction.

In this embodiment, the plurality of wall portions 121 are integrally formed, so that the wall portion 121 where the groove portion 53 is disposed has better reliability.

In some embodiments, please continue to refer to Figures 38 and 39, the multiple wall portions 121 include a bottom wall 121b and multiple side walls 121a surrounding the bottom wall 121b, and the housing 12 forms an opening at one end opposite to the bottom wall 121b. The bottom wall 121b is provided with a groove portion 53; and/or at least one side wall 121a is provided with a groove portion 53.

In this embodiment, the housing 12 is a hollow structure with an opening formed at one end. The side walls 121a in the housing 12 may be three, four, five, six or more. One, two, three, four, five, six or more side walls 121a may be provided with a groove 53.

As an example, in Figure 38, only one side wall 121a is provided with a groove portion 53 to correspondingly form a weak area 52 and a non-weak area 51 on the side wall 121a; in Figure 39, only the bottom wall 121b is provided with a groove portion 53 to correspondingly form a weak area 52 and a non-weak area 51 on the bottom wall 121b.

In some embodiments, please continue to refer to Figures 38 and 39, the shell 12 is a rectangular parallelepiped.

It can be understood that there are four side walls 121 a in the housing 12 .

The rectangular parallelepiped housing is suitable for square battery cells and can meet the large capacity requirements of the battery cells 10 .

In some embodiments, the material of the housing component 5 includes aluminum alloy.

The housing component 5 made of aluminum alloy is light in weight, has good ductility, good plastic deformation capability, and is easy to form.

In the embodiment of 0.2≤A/B≤0.5, since aluminum alloy has good ductility, it is easier to control A/B to be less than 0.5 (including 0.5) when forming the groove portion 53 on the shell component 5 by stamping, and the forming rate is higher.

In some embodiments, the aluminum alloy includes the following components in mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%. This aluminum alloy has lower hardness and better forming ability, reduces the forming difficulty of the groove 53, improves the forming accuracy of the groove 53, and improves the pressure relief consistency of the housing component 5.

In some embodiments, the aluminum alloy includes the following components in percentage by mass: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single element components ≤ 0.05%, and other elements in total ≤ 0.15%. The housing component 5 made of such an aluminum alloy has higher hardness, greater strength, and better anti-destruction ability.

An embodiment of the present application provides a battery cell 10, comprising a housing component 5 provided in any one of the above embodiments.

In some embodiments, the battery cell 10 further includes a housing 12 having an opening, and the housing 12 is used to accommodate the electrode assembly 2. The housing component 5 is an end cover 11, and the end cover 11 closes the opening.

In some embodiments, the housing component 5 is a shell 12 having an opening, and the shell 12 is used to accommodate the electrode assembly 2. The battery cell 10 further includes an end cover 11, which closes the opening.

An embodiment of the present application provides a battery 100, comprising a battery cell 10 provided in any one of the above embodiments.

In some embodiments, please refer to FIG. 40 , which is a schematic diagram of the structure of a battery cell 10 provided in some embodiments of the present application, and the weak area 52 is located at the lower part of the battery cell 10 .

In the battery cell 10, along the height direction of the shell 1 of the battery cell 10, the portion of the battery cell 10 below the midplane Y of the shell 1 is the lower portion of the battery cell 10, wherein the midplane Y is perpendicular to the height direction of the shell 1, and the distances from the midplane Y to the two end surfaces of the shell 1 in the height direction are equal. For example, the shell 1 includes a shell 12 and an end cover 11, and the end cover 11 closes the opening of the shell 12. The shell 12 and the end cover 11 are arranged along the height direction of the shell 1, and along the height direction of the shell 1, the midplane Y is located at the middle position between the outer surface of the end cover 11 facing away from the shell 12 and the outer surface of the shell 12 facing away from the end cover 11.

The weak area 52 is located at the lower part of the battery cell 10, and the groove 53 is located at the lower part of the battery cell 10, and the weak area 52 and the groove 53 are both located below the midplane Y. The weak area 52 can be located at the shell 12, and the weak area 52 can also be located at the end cover 11. The weak area 52 can be located at the side wall 121a of the shell 12, and can also be located at the bottom wall 121b of the shell 12. As shown in FIG40, taking the weak area 52 located at the side wall 121a of the shell 12 as an example, the bottom wall 121b of the shell 12 can be located below the end cover 11, and the weak area 52 is located below the midplane Y, so that the distance from the weak area 52 to the bottom wall 121b of the shell 12 is greater than the distance from the weak area 52 to the end cover 11.

Since the weak area 52 is located at the lower part of the battery cell 10, during the use of the battery 100, the weak area 52 will be subjected to a large force under the gravity of the electrode assembly 2, electrolyte, etc. inside the battery cell 10. Since the weak area 52 and the non-weak area 51 are an integrally formed structure, they have good structural strength and better reliability, thereby increasing the service life of the battery cell 10.

In some embodiments, the battery cell 10 includes a shell 12, which is used to accommodate the electrode assembly 2. The shell 12 includes an integrally formed bottom wall 121b and multiple side walls 121a surrounding the bottom wall 121b. The bottom wall 121b and the side walls 121a are integrally formed. The shell 12 forms an opening at the end opposite to the bottom wall 121b, and the weak area 52 is located at the bottom wall 121b.

It can be understood that the bottom wall 121b is located below the midplane Y.

In this embodiment, the weak area 52 is located at the bottom wall 121b, so that the weak area 52 is set downward. When the battery cell 10 is in thermal runaway, after the weak area 52 is destroyed, the emissions in the battery cell 10 will be ejected downward, reducing the risk of safety accidents. For example, in the vehicle 1000, the battery 100 is generally installed below the passenger compartment, and the weak area 52 is set downward, so that the emissions discharged by the battery cell 10 in thermal runaway are ejected in the direction away from the passenger compartment, reducing the impact of the emissions on the passenger compartment and reducing the risk of safety accidents.

In some embodiments, the battery cell 10 includes an end cover 11 , which is used to close an opening of a shell 12 , and the shell 12 is used to accommodate the electrode assembly 2 . The weak area 52 is located at the end cover 11 .

It can be understood that the end cover 11 is located below the midplane Y.

In this embodiment, the weak area 52 is located at the end cover 11, so that the weak area 52 is set downward. When the battery cell 10 thermally runs away, after the weak area 52 is destroyed, the emissions in the battery cell 10 will spray downward, reducing the risk of safety accidents.

An embodiment of the present application provides an electrical device, comprising the battery 100 provided in any one of the above embodiments.

In some embodiments, the embodiments of the present application provide an end cap 11 for a battery cell 10, and the end cap 11 includes an integrally formed non-weak area 51 and a weak area 52. The end cap 11 is provided with a groove 53, the non-weak area 51 is formed around the groove 53, and the weak area 52 is formed at the bottom of the groove 53, and the weak area 52 is configured to be destroyed when the battery cell 10 releases internal pressure. The end cap 11 has a first surface 54 facing away from the interior of the battery cell 10, and the groove 53 forms an outer edge 534 on the first surface 54. The area of the end cap 11 outside the preset distance from the outer edge 534 is the non-weak area 51, and the preset distance is L, L=5mm. The minimum thickness of the weak zone 52 is A, the minimum thickness of the non-weak zone 51 is B, the average grain size of the weak zone 52 is S ₁ , the average grain size of the non-weak zone 51 is S ₂ , the hardness of the weak zone 52 is H ₁ , the hardness of the non-weak zone 51 is H ₂ , and the following conditions are satisfied: 0.2≤A/B≤0.5, 0.1≤S ₁ /S ₂ ≤0.5, 5≤A/S ₁ ≤20, 190HBW/mm≤H ₁ /A≤4000HBW/mm, 1＜H ₁ /H ₂ ≤2.5.

In some embodiments, the present application provides a shell 12 for a battery cell 10, and the shell 12 includes a non-weak area 51 and a weak area 52 formed in one piece. The shell 12 is provided with a groove 53, the non-weak area 51 is formed around the groove 53, and the weak area 52 is formed at the bottom of the groove 53, and the weak area 52 is configured to be destroyed when the battery cell 10 releases internal pressure. The shell 12 has a first surface 54 facing away from the interior of the battery cell 10, and the groove 53 forms an outer edge 534 on the first surface 54. The area of the shell 12 outside the preset distance from the outer edge 534 is the non-weak area 51, and the preset distance is L, L=5mm. The average grain size of the weak area 52 is S ₁ , the average grain size of the non-weak area 51 is S ₂ , the minimum thickness of the weak area 52 is A, the minimum thickness of the non-weak area 51 is B, the hardness of the weak area 52 is H ₁ , the hardness of the non-weak area 51 is H ₂ , and the following conditions are satisfied: 0.2≤A/B≤0.5, 0.1≤S ₁ /S ₂ ≤0.5, 5≤A/S ₁ ≤20, 190HBW/mm≤H ₁ /A≤4000HBW/mm, 1＜H ₁ /H ₂ ≤2.5.

The features and performance of the present application are further described in detail below in conjunction with the embodiments.

In each embodiment and comparative example, the battery cell 10 is a square battery cell, the end cover 11 in the battery cell 10 serves as the outer shell component 5, the capacity of the battery cell 10 is 150 Ah, and the chemical system is NCM.

1. Test Method

(1) Hardness test of the weak area 52 and the non-weak area 51.

Cut the housing component 5 into three sections, take the middle section as the sample, and the sections at both ends of the sample have weak areas 52 and non-weak areas 51. The cutting direction is perpendicular to the length direction of the weak area 52. After the test section is polished to fully remove burrs, the sample is placed horizontally (the direction of the sample section is parallel to the extrusion direction of the hardness tester) on the Brinell hardness tester for hardness measurement. If the width of the weak area 52 is less than 1mm or the size of the indenter of the Brinell hardness tester is much larger than the width of the weak area 52, a non-standard indenter should be processed for hardness measurement according to the Brinell hardness measurement and conversion principle.

(2) Average grain size test of the weak area 52 and the non-weak area 51.

The average grain size test of the weak area 52 and the non-weak area 51 adopts the electron backscatter diffraction (EBSD) method. The shell component 5 is cut into sections, and the cross sections at both ends of the middle section have weak areas 52 and non-weak areas 51. The cutting direction is perpendicular to the length direction of the weak area 52, and the cutting equipment does not change the grain structure. The middle section is selected for sampling, and then the sample is electrolytically polished, and the sample is fixed on a sample table inclined at 70°. The appropriate magnification is selected, and an EBSD scan is performed using a scanning electron microscope (SEM) equipped with an electron backscatter diffraction (EBSD) accessory. According to the scanning results, the average grain size (i.e., the equal area circle diameter of the complete grains in the inspection surface) is finally calculated.

(3) Minimum thickness test of weak area 52 and non-weak area 51.

The housing component 5 is cut into three sections, and the middle section is taken as a sample. The sections at both ends of the sample have weak areas 52 and non-weak areas 51. The cutting direction is perpendicular to the length direction of the weak area 52. After the middle section is polished to fully remove burrs, the sample is placed on a three-dimensional coordinate measuring instrument to measure the thickness of the weak area 52 and non-weak area 51 on the section.

(4) The cracking rate of the weak area 52 under normal use conditions of the battery cell 10.

The battery cell 10 is placed at 25±2℃ and cycled with 5%-97% SOC. The gas pressure inside the battery cell 10 is monitored and 500 groups of tests are performed at the same time. The test cutoff condition is: the battery cell 10 life drops to 80% SOH or any group of battery cells 10 cracks in the weak area 52 during the cycle. Among them, the judgment condition for the cracking of the weak area 52 is: the internal gas pressure value of the battery cell 10 drops, and its drop value is greater than 10% of the maximum gas pressure. The cracking rate of the weak area 52 is calculated, and the cracking rate = the number of cracks/total number*100%.

(5) The explosion rate of the battery cell 10 during thermal runaway.

A small heating film is built into the battery cell 10. The heating film is energized to heat the battery cell 10 until the battery cell 10 experiences thermal runaway, and then observe whether the battery cell 10 explodes. Repeat 500 sets of tests, and calculate the explosion rate of the battery cell 10. The explosion rate = the number of explosions/the total number*100%.

2. Test Results

In each embodiment and comparative example, the test results of the hardness _H1 of the weak area 52, the hardness _H2 of the non-weak area 51, the average grain size _S1 of the weak area 52, the average grain size _S2 of the non-weak area 51, the minimum thickness A of the weak area 52 and the minimum thickness B of the non-weak area 51 are shown in Table 1. In Table 1, the unit of _H1 and _H2 is HBW, the unit of _S1 and _S2 is mm, and the unit of A and B is mm; the cracking rate _Q1 of the weak area 52 under normal use conditions of the battery cell 10 and the explosion rate _Q2 of the battery cell 10 during thermal runaway are shown in Table 2.

Table I

Table II

The	Q ₁ Q ₁	Q ₂ Q ₂
实施例1Example 1	0.8％0.8%	9.6％9.6%
实施例2Example 2	1.2％1.2%	8.4％8.4%
实施例3Example 3	1.6％1.6%	5.8％5.8%
实施例4Example 4	2.2％2.2%	3.4％3.4%
实施例5Example 5	2.4％2.4%	2％2%
实施例6Example 6	3.4％3.4%	1.6％1.6%
实施例7Example 7	5.4％5.4%	1％1%
实施例8Example 8	8.2％8.2%	0.8％0.8%
实施例9Example 9	9.2％9.2%	0.6％0.6%
实施例10Example 10	8％8%	0.8％0.8%

实施例11Embodiment 11	6％6%	1.6％1.6%
实施例12Example 12	3.0％3.0%	2.4％2.4%
实施例13Example 13	1.6％1.6%	3.6％3.6%

实施例14Embodiment 14	0.8％0.8%	6.4％6.4%
实施例15Embodiment 15	0.6％0.6%	8.2％8.2%
实施例16Example 16	0.8％0.8%	8％8%
实施例17Embodiment 17	1.6％1.6%	4.4％4.4%
实施例18Embodiment 18	2.2％2.2%	3.6％3.6%
实施例19Embodiment 19	3.4％3.4%	1.8％1.8%

实施例20Embodiment 20	4.2％4.2%	1.4％1.4%

实施例21Embodiment 21	8.4％8.4%	0.6％0.6%

实施例22Embodiment 22	8.2％8.2%	0.8％0.8%
实施例23Embodiment 23	6.2％6.2%	1.8％1.8%
实施例24Embodiment 24	3.4％3.4%	3.2％3.2%
实施例25Embodiment 25	2％2%	4.2％4.2%
实施例26Embodiment 26	1.2％1.2%	5.6％5.6%
实施例27Embodiment 27	0.6％0.6%	8.4％8.4%
实施例28Embodiment 28	0.6％0.6%	9.2％9.2%
实施例29Embodiment 29	0.8％0.8%	8.2％8.2%
实施例30Embodiment 30	1.4％1.4%	6.0％6.0%
实施例31Embodiment 31	3％3%	4.2％4.2%

实施例32Embodiment 32	4.4％4.4%	2.0％2.0%
实施例33Embodiment 33	5.8％5.8%	1.4％1.4%
实施例34Embodiment 34	7.4％7.4%	1％1%
实施例35Embodiment 35	8.8％8.8%	0.6％0.6%
对比例1Comparative Example 1	12.2％12.2%	0.6％0.6%
对比例2Comparative Example 2	14.2％14.2%	0.4％0.4%

Combining Table 1 and Table 2, it can be seen from Examples 1 to 8 that when H ₁ /H ₂ >1, the cracking rate of the weak area 52 under normal use conditions of the battery cell 10 is low. In Comparative Example 1, H ₁ /H ₂ =1, the cracking rate of the weak area 52 under normal use conditions of the battery cell 10 is high, and the cracking rate is greater than 12%; in Comparative Example 2, H ₁ /H ₂ <1, the cracking rate of the weak area 52 under normal use conditions of the battery cell 10 is high, and the cracking rate is also greater than 12%. Comparing Examples 1 to 8 with Comparative Examples 1 to 2, it can be seen that when H ₁ /H ₂ >1, the cracking rate of the weak area 52 under normal use conditions of the battery cell 10 can be effectively reduced. Comparing Examples 2 to 8 with Example 1, it can be seen that when H ₁ /H ₂ >5, the explosion rate of the battery cell 10 during thermal runaway is high. H ₁ /H ₂ ≤5 can reduce the risk of explosion of the battery cell 10.

According to Examples 10 to 15, when S ₁ /S ₂ ≤0.9, the cracking rate of the weak area 52 under normal use conditions of the battery cell 10 is low. In Example 9, S ₁ /S ₂ >0.9, and the cracking rate of the weak area 52 under normal use conditions of the battery cell 10 is significantly increased. Comparing Examples 10 to 15 with Example 9, it can be seen that controlling S ₁ /S ₂ to not more than 0.9 can effectively reduce the risk of the weak area 52 being damaged under normal use conditions of the battery cell 10, thereby increasing the service life of the battery cell 10.

According to Example 15, when S ₁ /S ₂ ＜0.05, it is more difficult for the weak area 52 to be destroyed when the battery cell 10 is in thermal runaway, and the pressure relief is not timely, and the risk of explosion of the battery cell 10 is significantly increased. Comparing Examples 9 to 14 and 15, it can be seen that controlling S ₁ /S ₂ to not less than 0.5 can effectively reduce the explosion rate of the battery cell 10 in thermal runaway. When 0.1≤S ₁ /S ₂ ≤0.5, the cracking rate of the weak area 52 under normal use conditions of the battery cell 10 and the explosion rate of the battery cell 10 in thermal runaway are both low, ensuring that the weak area 52 can be destroyed in time when the battery cell 10 is in thermal runaway, and ensuring that the weak area 52 has sufficient strength under normal use conditions of the battery cell 10.

From the comparison between Examples 17 to 21 and Example 16, it can be seen that when 1≤A/S ₁ ≤100, the battery cell 10 can release pressure in time when thermal runaway occurs, and the explosion rate of the battery cell 10 is low. When 5≤A/S ₁ ≤20, the overall performance of the battery cell 10 is better, and the cracking rate of the weak area 52 under normal use conditions of the battery cell 10 and the explosion rate of the battery cell 10 when thermal runaway occur are both low.

From the comparison between Examples 23 to 27 and Example 22, it can be seen that when H ₁ /A＞10000HBW/mm, the cracking rate of the weak area 52 under the normal use conditions of the battery cell 10 is high. From the comparison between Examples 22 to 26 and Example 27, it can be seen that when H ₁ /A＜5HBW/mm, the explosion rate of the battery cell 10 during thermal runaway is high. 5HBW/mm≤H ₁ /A≤10000HBW/mm can reduce the risk of rupture of the weak area 52 under the normal use conditions of the battery cell 10, and can timely release pressure through the weak area 52 during thermal runaway of the battery cell 10, thereby reducing the risk of explosion of the battery cell 10. From Examples 24 to 25, it can be seen that when 190HBW/mm≤H ₁ /A≤4000HBW/mm, the comprehensive performance of the battery cell 10 is better, and the cracking rate of the weak area 52 under the normal use conditions of the battery cell 10 and the explosion rate of the battery cell 10 during thermal runaway are both low.

It can be seen from the comparison between Examples 29 to 35 and Example 28 that when A/B>0.95, the explosion rate of the battery cell 10 during thermal runaway is relatively high. Comparing Examples 28 to 34 and Example 35, it can be seen that when A/B<0.05, the cracking rate of the weak area 52 under normal use conditions of the battery cell 10 is relatively high. While 0.05≤A/B≤0.95 can not only reduce the risk of rupture of the weak area 52 under normal use conditions of the battery cell 10, but also can timely release pressure through the weak area 52 when the battery cell 10 is in thermal runaway, thereby reducing the risk of explosion of the battery cell 10. It can be seen from Examples 30 to 33 that when 0.12≤A/B≤0.8, the comprehensive performance of the battery cell 10 is better, the cracking rate of the weak area 52 under normal use conditions of the battery cell 10 and the explosion rate of the battery cell 10 during thermal runaway are both low, and 0.2≤A/B≤0.5 has a better effect.

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

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 modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

A shell component for a battery cell, comprising an integrally formed non-weak area and a weak area, the shell component being provided with a groove portion, the non-weak area being formed around the groove portion, the weak area being formed at the bottom of the groove portion, and the weak area being configured to be destroyed when the battery cell releases internal pressure;

The hardness of the weak area is H 1 , and the hardness of the non-weak area is H 2 , satisfying: H 1 >H 2 .
The housing component according to claim 1, wherein H 1 /H 2 ≤5; preferably, H 1 /H 2 ≤2.5.
The housing component according to claim 1 or 2, wherein 5HBW≤H 1 ≤200HBW.
The housing component according to any one of claims 1 to 3, wherein 5HBW≤H 2 ≤150HBW.
The housing component according to any one of claims 1 to 4, wherein the average grain size of the weak area is S 1 , and the average grain size of the non-weak area is S 2 , satisfying: S 1 /S 2 ≤0.9.
The housing component according to claim 5, wherein S 1 /S 2 ≥ 0.05; preferably, 0.1≤S 1 /S 2 ≤ 0.5.
The housing component according to claim 5 or 6, wherein 0.4 μm ≤ S 1 ≤ 75 μm; preferably, 1 μm ≤ S 1 ≤ 10 μm.
The housing component according to any one of claims 5 to 7, wherein 10 μm ≤ S 2 ≤ 150 μm; preferably, 30 μm ≤ S 2 ≤ 100 μm.
The housing component according to any one of claims 1 to 8, wherein the minimum thickness of the weak area is A, and the average grain size of the weak area is S 1 , satisfying: 1≤A/S 1 ≤100; preferably, 5≤A/S 1 ≤20.
The housing component according to any one of claims 1 to 9, wherein the minimum thickness of the weak area is A, satisfying: 5HBW/mm≤H 1 /A≤10000HBW/mm; preferably, 190HBW/mm≤H 1 /A≤4000HBW/mm.
The housing component according to any one of claims 1 to 10, wherein the minimum thickness of the weak area is A, and the minimum thickness of the non-weak area is B, satisfying: 0.05≤A/B≤0.95; preferably, 0.12≤A/B≤0.8; preferably, 0.2≤A/B≤0.5.
The housing component according to claim 11, wherein 1 mm ≤ B ≤ 5 mm; preferably, 1.2 mm ≤ B ≤ 3.5 mm; preferably, 2 mm ≤ B ≤ 3 mm.
The housing component according to any one of claims 9 to 12, wherein 0.02 mm ≤ A ≤ 1.6 mm; preferably, 0.06 mm ≤ A ≤ 0.4 mm.
The shell component according to any one of claims 1 to 13, wherein the shell component has a pressure relief zone, the groove portion includes a primary notch groove, the notch groove is arranged along the edge of the pressure relief zone, the pressure relief zone is configured to be openable with the notch groove as a boundary, and the weak zone forms the bottom of the notch groove.
The housing component according to claim 14, wherein the housing component has a first surface and a second surface arranged opposite to each other, and the notch groove is recessed from the first surface toward the second surface.
The housing component according to any one of claims 1 to 13, wherein the housing component comprises a first surface and a second surface arranged opposite to each other, the groove portion comprises a multi-stage notched groove, the multi-stage notched groove is sequentially arranged on the housing component along a direction from the first surface to the second surface, and the weak area is formed at the bottom of the first stage notched groove farthest from the first surface;

The shell component has a pressure relief zone, each level of the notched groove is arranged along the edge of the pressure relief zone, and the pressure relief zone is configured to be able to open with the level of the notched groove farthest from the first surface as a boundary.
The housing component according to claim 16, wherein the first-level notch groove farthest from the second surface is recessed from the first surface toward the second surface.
The shell component according to claim 14 or 16, wherein the shell component includes a first surface and a second surface arranged opposite to each other, the groove portion also includes a primary groove, the groove is recessed from the first surface toward the direction close to the second surface, and the pressure relief zone is formed on the bottom wall of the groove.
The shell component according to claim 14 or 16, wherein the shell component includes a first surface and a second surface arranged opposite to each other, and the groove portion further includes a multi-stage groove, the multi-stage groove is sequentially arranged on the shell component along the direction from the first surface to the second surface, the first-stage groove farthest from the second surface is recessed from the first surface to the second surface, and the pressure relief zone is formed on the bottom wall of the groove of the first-stage groove farthest from the first surface.
The housing component according to claim 18 or 19, wherein the inner space of the sink is a cylinder, a prism, a truncated cone or a truncated pyramid.
The housing component according to any one of claims 14 to 20, wherein the notched groove comprises a first groove segment and a second groove segment, the first groove segment intersects with the second groove segment, and the first groove segment and the second groove segment are arranged along an edge of the pressure relief zone.
The housing component according to claim 21, wherein the notched groove further comprises a third groove segment, the first groove segment and the third groove segment are arranged opposite to each other, the second groove segment intersects with the third groove segment, and the first groove segment, the second groove segment and the third groove segment are arranged along the edge of the pressure relief zone.
The housing component according to claim 22, wherein the first slot segment, the second slot segment and the third slot segment are connected in sequence, and the first slot segment, the second slot segment and the third slot segment define a pressure relief zone.
The housing component according to claim 22, wherein the first slot segment, the second slot segment and the third slot segment define two pressure relief areas, and the two pressure relief areas are respectively located on both sides of the second slot segment.
The housing component according to any one of claims 14 to 20, wherein the notched groove is a groove extending along a non-closed trajectory.
The housing component according to any one of claims 14 to 20 and 25, wherein the notched groove is an arc-shaped groove.
The housing component according to any one of claims 14 to 20, wherein the notched groove is a groove extending along a closed trajectory.
The housing component according to any one of claims 14 to 20 and 27, wherein the notched groove is an annular groove.
The housing component according to any one of claims 14 to 28, wherein the area of the pressure relief zone is D, satisfying: 90 mm 2 ≤ D ≤ 1500 mm 2 ; preferably, 150 mm 2 ≤ D ≤ 1200 mm 2 ; preferably, 200 mm 2 ≤ D ≤ 1000 mm 2 ; preferably, 250 mm 2 ≤ D ≤ 800 mm 2 .
The shell component according to any one of claims 1 to 29, wherein the shell component has a first surface and a second surface arranged opposite to each other, the groove portion is recessed from the first surface toward the direction close to the second surface, the groove portion forms an outer edge on the first surface, and the area of the shell component outside a preset distance from the outer edge is the non-weak area.
The housing component according to claim 30, wherein the preset distance is L, satisfying: L = 5 mm.
The shell component according to any one of claims 1 to 31, wherein the shell component further comprises a transition zone, wherein the transition zone connects the weak zone and the non-weak zone, and an average grain size of the transition zone is S 3 , satisfying: S 3 ≤S 2 .
The shell component according to any one of claims 1 to 32, wherein the shell component is an end cover, the end cover is used to close the opening of the shell, and the shell is used to accommodate the electrode assembly.
The housing component according to any one of claims 1 to 32, wherein the housing component is a shell having an opening, and the shell is used to accommodate the electrode assembly.
The housing component according to claim 34, wherein the shell includes a plurality of integrally formed wall portions, the plurality of wall portions together define an internal space of the shell, and at least one of the wall portions is provided with the groove portion.
The housing component according to claim 35, wherein the plurality of wall portions include a bottom wall and a plurality of side walls surrounding the bottom wall, and the housing forms the opening at an end opposite to the bottom wall;

The bottom wall is provided with the groove; and/or

At least one of the side walls is provided with the groove portion.
The housing component according to any one of claims 34 to 36, wherein the shell is a rectangular parallelepiped.
The shell component according to any one of claims 1 to 37, wherein the material of the shell component includes aluminum alloy.
The housing component according to claim 38, wherein the aluminum alloy includes the following components in mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%.
The housing component according to claim 38, wherein the aluminum alloy includes the following components in percentage by mass: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single element components ≤ 0.05%, and the total composition of other elements ≤ 0.15%.
A battery cell, comprising:

A housing component as claimed in any one of claims 1 to 40.
The battery cell according to claim 41, wherein the battery cell further comprises a shell having an opening, the shell being used to accommodate the electrode assembly;

The housing component is an end cover, and the end cover closes the opening.
The battery cell according to claim 41, wherein the housing component is a shell having an opening, and the shell is used to accommodate the electrode assembly;

The battery cell further includes an end cover that closes the opening.
A battery comprising the battery monomer according to any one of claims 41 to 43.
The battery according to claim 44, wherein the weak area is located at a lower portion of the battery cell.
A battery according to claim 45, wherein the battery cell includes a shell, the shell is used to accommodate the electrode assembly, the shell includes a bottom wall and a plurality of side walls surrounding the bottom wall, the bottom wall and the side walls are integrally formed, the shell forms an opening at an end opposite to the bottom wall, and the weak area is located on the bottom wall.
The battery according to claim 45, wherein the battery cell includes an end cover for closing an opening of a shell, the shell is used to accommodate the electrode assembly, and the weak area is located at the end cover.
An electrical device comprising the battery according to any one of claims 44 to 47.