Battery cell, battery, and electrical device

Abstract

The present application belongs to the technical field of batteries. Provided in the embodiments are a battery cell, a battery and an electrical device. The battery cell comprises a casing and a pressure relief member. The casing comprises a first wall part, the pressure relief member being arranged on the first wall part. The pressure relief member is provided with a first recess, the pressure relief member being configured to be capable of cracking along at least a portion of the first recess during the pressure relief of the batter cell. The first recess comprises at least one recess section, the minimum width of the bottom surface of the recess section being W and, in the thickness direction of the first wall part, the minimum residual thickness of the recess section being D1 and satisfying: 0.005mm2≤W×D1≤0.12mm2. The service life requirement of battery cells in normal use and the reliability requirement of the battery cells during thermal runaway are both taken into consideration.

Description

Battery cells, batteries and electrical equipment Technical Field

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

[0002] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and power tools.

[0003] For general battery cells, they need to meet not only reliability requirements but also service life requirements. Therefore, how to balance the service life requirements of battery cells during normal use and the reliability requirements of battery cells during thermal runaway is an urgent problem to be solved in battery technology.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can take into account both the service life requirements of the battery cell during normal use and the reliability requirements of the battery cell during thermal runaway.

[0006] In a first aspect, an embodiment of the present application provides a battery cell, comprising a housing and a pressure relief component, wherein the housing comprises a first wall portion, and the pressure relief component is disposed on the first wall portion; the pressure relief component is provided with a first groove, and the pressure relief component is configured to be able to split along at least a portion of the first groove when the battery cell is depressurized; wherein the first groove comprises at least one groove segment, the minimum width of the groove bottom surface of the groove segment is W, and the minimum residual thickness of the groove segment along the thickness direction of the first wall portion is D1, which satisfies: 0.005mm 2 ≤W×D1≤0.12mm 2 .

[0007] In the above technical solution, the pressure relief component is provided with a first groove, so that the pressure relief component can be split along at least a portion of the first groove when the battery cell is depressurized, thereby releasing the internal pressure of the battery cell. W×D1≥0.005mm 2 This prevents the minimum width of the groove bottom surface of the groove segment from being too small, and the minimum residual thickness of the groove segment from being too small. This reduces the risk of insufficient fatigue strength in the area where the pressure relief component is located due to the minimum width of the groove bottom surface and the minimum residual thickness of the groove segment being too small. This improves the fatigue strength of the area where the pressure relief component is located, reduces the risk of the pressure relief component cracking prematurely along the groove segment during normal use of the battery cell, and increases the service life of the battery cell. W×D1≤0.12mm 2, so that the minimum width of the groove bottom surface of the groove section will not be too large, and the minimum residual thickness of the groove section will not be too large, which will alleviate the situation where the strength of the area where the pressure relief component is set in the groove section is too high due to the minimum width of the groove bottom surface of the groove section and the minimum residual thickness of the groove section being too large. When the battery cell is in thermal runaway, the pressure relief component can be cracked along the groove section more promptly, thereby improving the timeliness of the pressure relief of the battery cell, reducing the risk of battery cell explosion, and improving the reliability of the battery cell. Therefore, 0.005mm 2 ≤W×D1≤0.12mm 2 , taking into account the service life requirements of battery cells during normal use and the reliability requirements of battery cells in thermal runaway.

[0008] In some embodiments, 0.01 mm 2 ≤W×D1≤0.05mm 2 .W×D1≥0.01mm 2 , further improving the fatigue strength of the area where the pressure relief component is set in the groove section, further reducing the risk of the pressure relief component cracking along the groove section in advance during normal use of the battery cell, and further improving the service life of the battery cell; W×D1≤0.05mm 2 , so that the pressure relief component can be more timely cracked along the groove section when the battery cell thermal runaway occurs, further improving the timeliness of the pressure relief of the battery cell and further reducing the risk of battery cell explosion.

[0009] In some embodiments, 0.05 mm ≤ W ≤ 0.5 mm. When W ≥ 0.05 mm, the minimum width of the bottom surface of the groove segment is not too small, thereby reducing the difficulty of forming the groove segment. When W ≤ 0.5 mm, the minimum width of the bottom surface of the groove segment is not too large, thereby reducing the minimum residual thickness of the groove segment. This reduces the risk of cracking of the pressure relief component along the groove segment during the forming process, thereby improving the forming yield of the pressure relief component. On the other hand, it is not necessary to process the bottom surface of the groove segment too wide, thereby reducing the forming force applied to the pressure relief component during the forming process.

[0010] In some embodiments, 0.1 mm ≤ W ≤ 0.3 mm, which can further reduce the difficulty of forming the slot segment and further reduce the risk of the pressure relief component cracking along the slot segment during the forming process.

[0011] In some embodiments, 0.05 mm ≤ D1 ≤ 0.6 mm. D1 ≥ 0.05 mm ensures that the minimum residual thickness of the groove segment is not too small. This reduces the risk of cracking along the groove segment during the forming process of the pressure relief component and improves the forming yield of the pressure relief component. Furthermore, it eliminates the need to machine the groove bottom surface of the groove segment too wide, reducing the forming force applied to the pressure relief component during the forming process. When D1 ≤ 0.6 mm, the minimum residual thickness of the groove segment is not too large, eliminating the need to machine the groove bottom surface of the groove segment too narrow, thereby reducing the difficulty of forming the groove segment.

[0012] In some embodiments, 0.08 mm ≤ D1 ≤ 0.4 mm, which can further reduce the risk of the pressure relief component cracking along the groove segment during the groove segment forming process and further reduce the difficulty of forming the groove segment.

[0013] In some embodiments, the first groove defines at least one predetermined pressure relief area, and the pressure relief component is provided with a second groove. The second groove is configured to guide the flipping of at least a portion of the predetermined pressure relief area to open the predetermined pressure relief area. The second groove assists the flipping of the predetermined pressure relief area, making the flipping of the predetermined pressure relief area easier and reducing the difficulty of flipping the predetermined pressure relief area. This allows the predetermined pressure relief area to open more quickly during the process of the pressure relief component splitting along the first groove, thereby increasing the opening rate of the predetermined pressure relief area.

[0014] In some embodiments, the minimum residual thickness of the second groove is D2, satisfying the following: D1 < D2. This ensures that the strength of the region where the pressure relief component is provided with the groove section is less than the strength of the region where the second groove is provided, so that the pressure relief component can preferentially break along the first groove, thereby achieving rapid opening of the predetermined pressure relief area.

[0015] In some embodiments, along the thickness direction of the first wall portion, the maximum groove depth of the groove segment is H1, and the maximum groove depth of the second groove is H2, satisfying the following relationship: H2 < H1. By setting the maximum depth of the groove segment to be greater than the maximum depth of the second groove, the minimum residual thickness of the groove segment can be reduced to a value less than the minimum residual thickness of the second groove. During production, the depth of the groove segment can be machined deeper than the depth of the second groove, thereby reducing the minimum residual thickness of the groove segment to a value less than the minimum residual thickness of the second groove.

[0016] In some embodiments, the pressure relief component is provided with multiple second grooves, and the first groove defines multiple predetermined pressure relief areas, each of which corresponds to at least one second groove. In the event of thermal runaway of a battery cell, all of the predetermined pressure relief areas can be opened. Given a certain total pressure relief area of ​​the pressure relief component, the opening rate of the predetermined pressure relief areas can be increased, resulting in faster pressure relief.

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

[0018] In some embodiments, the second groove is spaced apart from the first groove along its width. This ensures that the projection of the second groove along the thickness of the first wall portion does not overlap with the projection of the first groove along the thickness of the first wall portion. This reduces the mutual influence between the first and second grooves during processing and reduces the residual stress between the region where the first groove is provided and the region where the second groove is provided. This reduces the risk of cracks in the pressure relief component along the first groove propagating to the second groove, thereby causing the pressure relief component to crack along the second groove.

[0019] In some embodiments, along the thickness direction of the first wall portion, two ends of the projection of the second groove in the extension direction respectively extend beyond two ends of the projection of the first groove, making the second groove longer and enhancing the auxiliary turning effect of the second groove on the predetermined pressure relief area.

[0020] In some embodiments, the pressure relief component has a first surface and a second surface disposed opposite each other along the thickness direction of the first wall portion, the first groove being disposed on the first surface, and the second groove being disposed on the second surface. The first groove and the second groove are located on opposite sides of the pressure relief component in the thickness direction, respectively, so that the first groove and the second groove can be processed separately on opposite sides of the pressure relief component, which helps to reduce the mutual influence between the first groove and the second groove during the processing.

[0021] In some embodiments, the first surface is the surface of the pressure relief component facing the outside of the housing, and the second surface is the surface of the pressure relief component facing the inside of the housing. The first surface is the surface of the pressure relief component facing the outside of the housing, so that the first groove is set on the outside of the pressure relief component, which facilitates the processing and forming of the first groove on the outside of the battery cell, which is beneficial to reducing the difficulty of forming the first groove and improving the production efficiency of the battery cell. The second surface is the surface of the pressure relief component facing the inside of the housing, so that the second groove is set on the inside of the pressure relief component. On the one hand, during the process of the predetermined pressure relief area being flipped outward and opened, the two opposite sides of the second groove in the width direction are not easy to abut each other, which is beneficial to increase the opening area of ​​the predetermined pressure relief area; on the other hand, the second groove is not exposed to the outside of the battery cell, reducing the risk of the pressure relief component being oxidized and corroded in the second groove area.

[0022] In some embodiments, the pressure relief component has a second surface facing the interior of the housing along the thickness direction of the first wall portion, and the second groove is disposed on the second surface. The second groove being disposed on the inner side of the pressure relief component, on the one hand, prevents the two opposing side surfaces of the second groove in the width direction from abutting against each other during the outward flipping and opening of the predetermined pressure relief area, thereby facilitating the expansion of the opening area of ​​the predetermined pressure relief area. On the other hand, the second groove is not exposed to the exterior of the battery cell, reducing the risk of oxidation and corrosion of the pressure relief component in the second groove area.

[0023] In some embodiments, the first wall portion is a rectangular wall portion, and the first groove and the second groove are arranged along the width direction of the first wall portion. The second groove is closer to the edge of the first wall portion in the width direction of the first wall portion, so that the area where the second groove is set in the pressure relief component has higher strength, reducing the risk of the pressure relief component cracking along the second groove when the battery cell releases pressure. In addition, during normal use of the battery cell, the expansion of the battery cell in the width direction of the first wall portion is greater than the expansion in the length direction of the first wall portion, and the expansion of the battery cell in the width direction of the first wall portion has a greater impact on the pressure relief component. The first groove and the second groove are arranged along the width direction of the first wall portion, and the second groove can effectively absorb the deformation energy of the battery cell when the battery cell expands and deforms along the width direction of the first wall portion, thereby reducing the impact of the expansion of the battery cell along the width direction of the first wall portion on the pressure relief component.

[0024] In some embodiments, the second groove extends along a straight line. The second groove is a straight groove with a simple structure and is easy to process and form.

[0025] In some embodiments, along the thickness direction of the first wall portion, the pressure relief component has a first surface and a second surface arranged opposite to each other, and the groove segment includes a plurality of grooves arranged sequentially from the first surface toward the second surface. In two adjacent grooves, the first groove farther from the first surface is arranged at the groove bottom surface of the first groove closer to the first surface. The first groove furthest from the first surface in the multi-stage groove is the first-stage groove, the minimum residual thickness of the first-stage groove is the minimum residual thickness of the groove segment, and the groove bottom surface of the first-stage groove is the groove bottom surface of the groove segment. By arranging the groove segments to have a plurality of grooves along the thickness direction of the first wall portion, each stage of the groove can be processed one by one in the direction from the first surface to the second surface when forming the groove segment, thereby reducing the forming depth of each stage of the groove, reducing the forming force applied to the pressure relief component when forming the first groove, and reducing the risk of damage to the pressure relief component when forming the first groove.

[0026] In some embodiments, the first groove includes multiple groove segments, including a first groove segment and a second groove segment, the first groove segment being connected to the second groove segment, and the first groove segment and the second groove segment jointly defining at least one predetermined pressure relief area. This structure provides a simple first groove structure, with more concentrated stress and a weaker position at the connection between the first and second groove segments. This allows the pressure relief component to rapidly rupture along the first and second groove segments after rupturing at the connection between the first and second groove segments during thermal runaway of the battery cell, thereby allowing the predetermined pressure relief area to open more quickly and relieve pressure in a timely manner.

[0027] In some embodiments, the first groove includes multiple groove segments, including a first groove segment, a second groove segment, and a third groove segment. The second groove segment and the third groove segment are arranged opposite each other, the first groove segment connects the second groove segment and the third groove segment, and the first groove segment, the second groove segment, and the third groove segment jointly define at least one predetermined pressure relief area. The first groove with this structure makes the intersection of the first groove segment and the second groove segment and the connection between the first groove segment and the third groove segment weaker, making it easier to rupture and open the predetermined pressure relief area for pressure relief. It can also further increase the open area of ​​the predetermined pressure relief area, thereby increasing the pressure relief area of ​​the battery cell and improving the pressure relief rate of the battery cell.

[0028] In some embodiments, the connection position between the second groove section and the first groove section is offset from both ends of the second groove section, and the connection position between the third groove section and the first groove section is offset from both ends of the third groove section, so that predetermined pressure relief areas are formed on both sides of the first groove section. This allows the first groove section of the first groove to be located between the two predetermined pressure relief areas. After the pressure relief component is split along the first groove section, the two predetermined pressure relief areas can open in a split manner to relieve pressure when the battery cell is depressurized. This allows the two predetermined pressure relief areas to open quickly, which helps to increase the pressure relief rate of the battery cell.

[0029] In some embodiments, the first slot segment extends along a straight line or an arcuate trajectory; and / or the second slot segment extends along a straight line or an arcuate trajectory; and / or the third slot segment extends along a straight line or an arcuate trajectory. If the first slot segment extends along a straight line, the first slot segment is a straight slot, which can reduce the difficulty of forming the first slot segment. If the first slot segment extends along an arcuate trajectory, the first slot segment is an arcuate slot, and the pressure relief component is more likely to split along the first slot segment when the battery cell is depressurized, thereby achieving a faster opening of the predetermined pressure relief area. If the second slot segment extends along a straight line, the second slot segment is a straight slot, which can reduce the difficulty of forming the second slot segment. If the second slot segment extends along an arcuate trajectory, the second slot segment is an arcuate slot, and the pressure relief component is more likely to split along the second slot segment when the battery cell is depressurized, thereby achieving a faster opening of the predetermined pressure relief area. If the third slot segment extends along a straight line, the third slot segment is a straight slot, which can reduce the difficulty of forming the third slot segment. If the third groove section extends along an arc trajectory, the third groove section is an arc-shaped groove, and the pressure relief component is more likely to split along the third groove section when the battery cell releases pressure, thereby achieving faster opening of the predetermined pressure relief area.

[0030] In some embodiments, the first groove extends along an arc track. The first groove extends along an arc track, that is, the first groove is an arc groove. The first groove of this structure only includes one groove segment, which simplifies the structure of the first groove.

[0031] In some embodiments, the pressure relief component is integrally formed with the first wall portion, so that the first groove can be directly formed on the first wall portion, forming an integrated pressure relief structure, which has higher reliability, eliminates the installation process of the pressure relief component, and has better economy.

[0032] In some embodiments, the pressure relief component is separately provided with the first wall portion and is mounted on the first wall portion. The pressure relief component is a component independent of the housing, and the pressure relief component and the housing can be produced and assembled separately, which is easy to produce and efficient.

[0033] In some embodiments, the first groove is stamped and formed on the pressure relief component. In this way, the molding method of the first groove is simple, which is conducive to reducing the production cost of the battery cell.

[0034] In some embodiments, the housing includes a shell and an end cap. The shell has an opening formed at least at one end. The end cap corresponds to the opening and closes the opening. At least one end cap is a first wall portion. This allows the at least one end cap to have a pressure relief function, making it easier to form the first groove on the end cap or to install a pressure relief component.

[0035] In some embodiments, the housing includes a shell and an end cap. The shell has an opening formed at least at one end, and the end cap corresponds to the opening in a one-to-one relationship, thereby sealing the opening. At least one wall portion of the shell is a first wall portion. This allows the shell to have a pressure relief function. When the battery cell is depressurized, the exhaust from the battery cell is less likely to affect external components outside the end cap, thereby reducing the risk of damage to the external components by the exhaust.

[0036] In some embodiments, the housing has an opening at only one end, and the wall of the housing opposite the end cap is the first wall. This single-end opening simplifies the overall battery cell structure. The first wall, the wall of the housing opposite the end cap, allows for directional pressure relief from the bottom of the housing.

[0037] In some embodiments, the housing has openings at both opposing ends, and at least one wall portion of the housing is a first wall portion. The housing has openings at both opposing ends, and the electrode assembly can be assembled into the housing through either opening, which can reduce the difficulty of assembling the battery cells and improve the assembly quality of the battery cells. This housing structure can be made taller (the housing has openings at both ends in the height direction), which helps increase the capacity of the battery cells.

[0038] In some embodiments, the pressure relief component is made of steel. Steel has high strength, and the pressure relief component made of steel has better strength. Under a certain bursting pressure of the battery cell, the pressure relief component can be made thinner, reducing the volume of the pressure relief component.

[0039] In some embodiments, the steel material is carbon steel or stainless steel.

[0040] In some embodiments, the pressure relief component is made of aluminum alloy, which is lightweight and ductile, making it easier to machine the first groove on the pressure relief component.

[0041] In some embodiments, the aluminum alloy includes the following composition by weight: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and any other individual element ≤ 0.03%. This aluminum alloy has lower hardness and better formability, reduces the difficulty of machining the first groove, improves the machining accuracy of the first groove, and enhances the pressure relief consistency of the pressure relief component.

[0042] In some embodiments, the aluminum alloy includes the following composition by weight: aluminum ≥ 96.7%, copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other individual elements ≤ 0.05%, and other elements combined ≤ 0.15%. Pressure relief components made from this aluminum alloy have increased hardness, strength, and excellent damage resistance.

[0043] In a second aspect, an embodiment of the present application provides a battery, comprising a battery cell provided by any embodiment of the first aspect.

[0044] In a third aspect, an embodiment of the present application provides an electrical device, comprising a battery cell provided by any one embodiment of the first aspect, wherein the battery cell is used to provide electrical energy to the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0046] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0047] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0048] FIG3 is an exploded view of a battery cell provided in some embodiments of the present application;

[0049] FIG4 is an assembly diagram of the battery cell 10 shown in FIG3 ;

[0050] FIG5 is a partial view of the housing 1 shown in FIG4 ;

[0051] FIG6 is an AA sectional view of the housing 1 shown in FIG5 ;

[0052] FIG7 is a partial enlarged view of point B in FIG6;

[0053] FIG8 is an assembly diagram of battery cells provided in some other embodiments of the present application;

[0054] FIG9 is a partial view of the housing shown in FIG8;

[0055] FIG10 is a CC sectional view of the housing shown in FIG9 ;

[0056] FIG11 is a partial enlarged view of point D in FIG10 ;

[0057] FIG12 is a partial enlarged view of point E in FIG11 ;

[0058] FIG13 is a partial view of a housing provided in some other embodiments of the present application;

[0059] FIG14 is a sectional view taken along line FF of the housing shown in FIG13 ;

[0060] FIG15 is a partial view of a housing 1 provided in some further embodiments of the present application;

[0061] FIG16 is a cross-sectional view taken along line GG of the housing 1 shown in FIG15 ;

[0062] FIG17 is an exploded view of a housing (an opening is formed at one end of the housing, and the end cover is a pressure relief component) provided in some embodiments of the present application;

[0063] FIG18 is an exploded view of a housing (an opening is formed at one end of the housing, the end cover is a first wall portion, and a pressure relief component is installed on the first wall portion) provided in some embodiments of the present application;

[0064] FIG19 is an exploded view of a housing (an opening is formed at one end of the housing, the housing includes a first wall portion, and the pressure relief component is the first wall portion) provided in some embodiments of the present application;

[0065] FIG20 is an exploded view of a housing (an opening is formed at one end of the housing, the housing includes a first wall portion, and a pressure relief component is mounted on the first wall portion) provided in some embodiments of the present application;

[0066] FIG21 is an exploded view of a battery cell provided in some other embodiments of the present application.

[0067] Icons: 1-housing; 11-shell; 12-end cover; 13-first wall; 131-pressure relief hole; 14-second wall; 15-third wall; 2-electrode assembly; 21-ear; 3-electrode terminal; 4-current collecting member; 5-insulating member; 6-pressure relief member; 61-first groove; 611-slot section; 6111-bottom surface of the slot section; 611a-first slot section; 611b-second slot section; 611c-third slot section; 6112-third Primary groove; 62-second groove; 621-first end; 622-second end; 623-bottom surface of the second groove; 63-predetermined pressure relief area; 64-first surface; 65-second surface; 10-battery cell; 20-housing; 201-first part; 202-second part; 100-battery; 200-controller; 300-motor; 1000-vehicle; U-first connection line; X-first direction; Y-second direction; Z-third direction. DETAILED DESCRIPTION

[0068] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0069] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0070] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0071] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0072] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0073] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0074] The term "plurality" used in this application refers to two or more (including two).

[0075] 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.

[0076] Battery cells include but are not limited to lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0077] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process, active ions (such as lithium ions) move back and forth between the positive and negative electrodes. A separator, placed between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0078] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0079] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0080] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0081] 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 LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0082] In some embodiments, a positive electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, among others. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0083] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

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

[0085] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0086] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0087] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0088] 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.

[0089] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical and mechanical stability.

[0090] As an example, the separator can be made of at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. In the case of a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0091] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0092] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0093] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0094] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0095] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0096] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0097] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0098] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0099] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0100] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0101] In some embodiments, the electrode assembly is a laminate structure.

[0102] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0103] 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.

[0104] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded segments that are stacked.

[0105] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0106] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0107] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0108] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0109] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0110] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. Prismatic battery cells include square-shell battery cells, blade-shaped battery cells, and polygonal prismatic batteries. Polygonal prismatic batteries are, for example, hexagonal prismatic batteries.

[0111] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0112] 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.

[0113] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0114] 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.

[0115] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0116] The development of battery technology must take into account multiple design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery safety must also be considered.

[0117] For battery cells, the main safety hazards come from the charging and discharging process, as well as the appropriate ambient temperature design. In order to effectively avoid unnecessary losses, there are generally at least three protection measures for battery cells. Specifically, the protection measures include at least switching elements, selection of appropriate isolation membrane materials, and pressure relief mechanisms. The switching element refers to the element that can stop the battery from charging or discharging when the temperature or resistance inside the battery cell reaches a certain threshold. The isolation membrane is used to isolate the positive and negative electrodes. When the temperature rises to a certain value, it can automatically dissolve the micron-level (or even nano-level) micropores attached to it, so that metal ions cannot pass through the isolation membrane, terminating the internal reaction of the battery cell.

[0118] A pressure relief mechanism refers to an element or component that is activated to release the internal pressure or temperature of a battery cell when the internal pressure or temperature reaches a predetermined threshold. The threshold design varies according to different design requirements. The threshold may depend on the material of one or more of the positive electrode sheet, negative electrode sheet, electrolyte and separator in the battery cell. The pressure relief mechanism can take the form of an explosion-proof valve, explosion-proof disk, air valve, pressure relief valve or safety valve, and can specifically adopt pressure-sensitive or temperature-sensitive elements or structures, that is, when the internal pressure or temperature of the battery cell reaches a predetermined threshold, the pressure relief mechanism executes an action or the weak structure provided in the pressure relief mechanism is destroyed, thereby forming an opening or channel for the internal pressure or temperature to be released.

[0119] The "activation" mentioned in this application refers to the action of the pressure relief mechanism or its activation to a certain state, thereby allowing the internal pressure and temperature of the battery cell to be released. The action produced by the pressure relief mechanism may include, but is not limited to: at least a portion of the pressure relief mechanism is ruptured, broken, torn or opened, etc. When the pressure relief mechanism is actuated, the high-temperature and high-pressure substances inside the battery cell will be discharged outward from the actuated part as emissions. In this way, the pressure and temperature of the battery cell can be relieved under controllable pressure or temperature, thereby avoiding potential more serious accidents.

[0120] The emissions from battery cells mentioned in this application include but are not limited to: electrolyte, dissolved or split positive and negative electrode sheets, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0121] In order to improve the reliability of battery cells, a pressure relief component can generally be provided in the battery cells. The pressure relief component can be a part of the battery cell shell or a component installed on the shell. When the battery cell thermally runs away, the pressure inside the battery cell can be released through the pressure relief component.

[0122] In order to achieve timely pressure relief of the battery cell, a pressure relief groove can be provided on the pressure relief component so that the pressure relief component can be split along at least a portion of the pressure relief groove when the battery cell is depressurized, thereby releasing the pressure inside the battery cell more quickly.

[0123] In order to meet the use requirements of the battery cell, the residual thickness of the pressure relief groove can be controlled within a reasonable range so that the pressure relief component has sufficient fatigue strength during normal use of the battery cell, and the pressure relief component can quickly crack along the pressure relief groove when the battery cell thermally runs away, thereby releasing pressure in time.

[0124] However, simply considering the impact of the residual thickness of the pressure relief groove on the performance of the battery cell still makes it difficult to balance the required service life of the battery cell during normal use with the required reliability of the battery cell during thermal runaway. This is because when addressing the issues of battery cell service life and reliability, it is necessary to consider not only the impact of the residual thickness of the pressure relief groove, but also the impact of the width of the groove bottom surface. The smaller the minimum width of the bottom surface of the pressure relief groove, the more likely the pressure relief component will experience stress concentration in the area where the pressure relief groove is set, and the smaller the strength of the pressure relief component in the area where the pressure relief groove is set; the smaller the minimum residual thickness of the pressure relief groove, the smaller the strength of the pressure relief component in the area where the pressure relief groove is set, and the smaller the fatigue strength of the area where the pressure relief groove is set during normal use of the battery cell; conversely, the larger the minimum width of the bottom surface of the pressure relief groove, the less likely the pressure relief component will experience stress concentration in the area where the pressure relief groove is set, the greater the strength of the pressure relief component in the area where the pressure relief groove is set, the more difficult it is for the pressure relief component to crack along the pressure relief groove when the battery cell thermal runaways, the less timely the pressure relief is, and the greater the risk of explosion of the battery cell; the larger the minimum residual thickness of the pressure relief groove, the greater the strength of the pressure relief component in the area where the pressure relief groove is set, the more difficult it is for the pressure relief component to crack along the pressure relief groove when the battery cell thermal runaways, the less timely the pressure relief is, and the greater the risk of explosion of the battery cell.

[0125] In view of this, an embodiment of the present application provides a battery cell, the battery cell including a housing and a pressure relief component, the housing including a first wall portion, and the pressure relief component is arranged on the first wall portion. The pressure relief component is provided with a first groove, and the pressure relief component is configured to be able to split along at least a portion of the first groove when the battery cell is depressurized. The first groove includes at least one groove segment, the minimum width of the groove bottom surface of the groove segment is W, and the minimum residual thickness of the groove segment along the thickness direction of the first wall portion is D1, which satisfies: 0.005mm 2 ≤W×D1≤0.12mm 2 .

[0126] In such a battery cell, W×D1≥0.005mm 2 This prevents the minimum width of the groove bottom surface of the groove segment from being too small, and the minimum residual thickness of the groove segment from being too small. This reduces the risk of insufficient fatigue strength in the area where the pressure relief component is located due to the minimum width of the groove bottom surface and the minimum residual thickness of the groove segment being too small. This improves the fatigue strength of the area where the pressure relief component is located, reduces the risk of the pressure relief component cracking prematurely along the groove segment during normal use of the battery cell, and increases the service life of the battery cell. W×D1≤0.12mm 2, so that the minimum width of the groove bottom surface of the groove section will not be too large, and the minimum residual thickness of the groove section will not be too large, which will alleviate the situation where the strength of the area where the pressure relief component is set in the groove section is too high due to the minimum width of the groove bottom surface of the groove section and the minimum residual thickness of the groove section being too large. When the battery cell is in thermal runaway, the pressure relief component can be cracked along the groove section more promptly, thereby improving the timeliness of the pressure relief of the battery cell, reducing the risk of battery cell explosion, and improving the reliability of the battery cell. Therefore, 0.005mm 2 ≤W×D1≤0.12mm 2 , taking into account the service life requirements of battery cells during normal use and the reliability requirements of battery cells in thermal runaway.

[0127] The battery cells described in the embodiments of the present application are suitable for batteries and electrical equipment using the battery cells.

[0128] Electrical equipment can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and electric tools, etc. Vehicles can be fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical equipment.

[0129] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0130] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of the present application. A battery 100 is disposed within vehicle 1000. Battery 100 can be located at the bottom, front, or rear of vehicle 1000. Battery 100 can be used to power vehicle 1000, for example, as an operating power source for vehicle 1000.

[0131] The vehicle 1000 may further include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0132] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0133] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a battery cell 10 and a housing 20, wherein the battery cell 10 is accommodated in the housing 20.

[0134] The housing 20 is a component that houses the battery cells 10 and provides a storage space for the battery cells 10. The housing 20 can have various structures. In some embodiments, the housing 20 can include a first portion 201 and a second portion 202, which overlap to define a storage space for the battery cells 10. The first portion 201 and the second portion 202 can have various shapes, such as a rectangular parallelepiped or a cylindrical shape. The first portion 201 can be a hollow structure with one side open, and the second portion 202 can be a hollow structure with one side open. The open side of the second portion 202 overlaps the open side of the first portion 201, thereby forming the housing 20 with a storage space. Alternatively, the first portion 201 can be a hollow structure with one side open, and the second portion 202 can be a plate-like structure. The second portion 202 overlaps the open side of the first portion 201, thereby forming the housing 20 with a storage space. The first portion 201 and the second portion 202 can be sealed by a sealing element, which can be a sealing ring, sealant, etc.

[0135] In the battery 100, there can be one or more battery cells 10. If there are multiple battery cells 10, the multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 10. Multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection to form a battery module, which can then be connected in series, parallel, or in a hybrid connection to form a single unit and housed within the housing 20. Alternatively, all battery cells 10 can be directly connected in series, parallel, or in a hybrid connection, and then the entire unit formed by all battery cells 10 can be housed within the housing 20.

[0136] Please refer to Figure 3, which is an exploded view of a battery cell 10 provided in some embodiments of the present application. The battery cell 10 may include a housing 1 and an electrode assembly 2, wherein the electrode assembly 2 is accommodated in the housing 1.

[0137] In some embodiments, the housing 1 may include a shell 11 and an end cover 12 , wherein the shell 11 has an opening and the end cover 12 closes the opening of the shell 11 .

[0138] The housing 11 is a component for accommodating the electrode assembly 2. The housing 11 can be a hollow structure with an opening at one end, or a hollow structure with openings at opposite ends. The housing 11 can have various shapes, such as a cylinder or a rectangular parallelepiped. The housing 11 can be made of various materials, such as copper, iron, aluminum, steel, and aluminum alloys.

[0139] The end cap 12 is a component that closes the opening of the shell 11 to isolate the internal environment of the battery cell 10 from the external environment. The end cap 12 and the shell 11 together define a receiving space for accommodating the electrode assembly 2, electrolyte and other components. The end cap 12 can be connected to the shell 11 by welding or rolling to close the opening of the shell 11. The shape of the end cap 12 can be adapted to the shape of the shell 1. For example, the shell 11 is a rectangular parallelepiped structure, and the end cap 12 is a rectangular plate structure adapted to the shell 1. For another example, the shell 11 is a cylindrical structure, and the end cap 12 is a circular plate structure adapted to the shell 11. The material of the end cap 12 can also be a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The material of the end cap 12 and the shell 11 can be the same or different.

[0140] In an embodiment where the housing 11 is open at one end, one end cap 12 may be provided. In an embodiment where the housing 11 is open at two opposite ends, two end caps 12 may be provided, each of which closes the two openings of the housing 11, and the two end caps 12 and the housing 11 together define a receiving space.

[0141] In some embodiments, the battery cell 10 may further include an electrode terminal 3, which is disposed on the outer casing 1. The electrode terminal 3 is used to electrically connect to the tab 21 of the electrode assembly 2 to output electrical energy from the battery cell 10. The electrode terminal 3 may be disposed on the shell 11 of the outer casing 1 or on the end cap 12 of the outer casing 1. The electrode terminal 3 and the tab 21 may be directly connected, for example, by direct welding the electrode terminal 3 and the tab 21. The electrode terminal 3 and the tab 21 may also be indirectly connected, for example, by indirectly connecting the electrode terminal 3 and the tab 21 through a current collecting member 4. The current collecting member 4 may be a metal conductor, such as copper, iron, aluminum, steel, an aluminum alloy, or the like.

[0142] As an example, as shown in FIG3 , an opening is formed at one end of the housing 11. There is only one end cap 12 in the outer shell 1, and each end cap 12 closes the opening of the housing 11. Two electrode terminals 3 are provided on the end cap 12, which are respectively a positive electrode terminal and a negative electrode terminal. A positive electrode tab and a negative electrode tab are formed on the end of the electrode assembly 2 facing the end cap 12. The positive electrode terminal is connected to the positive electrode tab via a current collecting member 4, and the negative electrode terminal is connected to the negative electrode tab via another current collecting member 4.

[0143] 3 , the battery cell 10 may further include an insulating member 5 . The insulating member 5 is a component that separates the housing 11 from the electrode assembly 2 , thereby achieving insulation isolation between the housing 11 and the electrode assembly 2 . The insulating member 5 is made of an insulating material, including but not limited to plastic, rubber, and the like.

[0144] As an example, the insulating member 5 wraps around the outside of the electrode assembly 2 along the circumference of the opening of the housing 11. There can be one or more electrode assemblies 2 within the housing 1. If there is a single electrode assembly 2, the insulating member 5 wraps around it. If there are multiple electrode assemblies 2, one insulating member 5 can be provided for each electrode assembly 2, with each insulating member 5 wrapping around a single electrode assembly 2. Alternatively, multiple electrode assemblies 2 can be formed as a single integral component, with the insulating member 5 wrapping around the integral component.

[0145] Please refer to Figures 4 to 7. Figure 4 is an assembly diagram of the battery cell 10 shown in Figure 3; Figure 5 is a partial view of the outer shell 1 shown in Figure 4; Figure 6 is an AA cross-sectional view of the outer shell 1 shown in Figure 5; and Figure 7 is a partial enlarged view of point B in Figure 6. An embodiment of the present application provides a battery cell 10, comprising an outer shell 1 and a pressure relief component 6, the outer shell 1 comprising a first wall portion 13, and the pressure relief component 6 is disposed on the first wall portion 13. The pressure relief component 6 is provided with a first groove 61, and the pressure relief component 6 is configured to be able to split along at least a portion of the first groove 61 when the battery cell 10 releases pressure. The first groove 61 includes at least one groove section 611, the minimum width of the groove bottom surface 6111 of the groove section is W, and the minimum residual thickness of the groove section 611 along the thickness direction of the first wall portion 13 is D1, which satisfies: 0.005mm 2 ≤W×D1≤0.12mm 2 .

[0146] The outer shell 1 may include multiple walls, which together define a receiving space inside the outer shell 1 to accommodate the battery cells 10, electrolyte, and other components. The other components may be current collecting members 4, insulating members 5, and other components. Among the multiple walls of the outer shell 1, one wall may be the first wall 13, or multiple walls may be the first wall 13. Taking the outer shell 1 as an example, if there are six walls in the outer shell 1 in the shape of a rectangular parallelepiped, one, two, three, four, five, or six walls may be the first wall 13. In the outer shell 1, at least one end cap 12 may be the first wall 13, or at least one wall in the shell 11 may be the first wall 13.

[0147] The pressure relief component 6 is a component within the battery cell 10 that relieves pressure within the battery cell 10. The pressure relief component 6 is disposed on the first wall portion 13. The pressure relief component 6 and the first wall portion 13 may be integrally formed, or they may be separate components, with the pressure relief component 6 being mounted on the first wall portion 13. If the pressure relief component 6 is integrally formed with the first wall portion 13, such that the pressure relief component 6 forms at least a portion of the first wall portion 13, the entire first wall portion 13 may serve as the pressure relief component 6, or a portion of the first wall portion 13 may serve as the pressure relief component 6.

[0148] The first groove 61 is a pressure relief groove provided in the pressure relief component 6. When the pressure inside the battery cell 10 reaches the bursting pressure of the pressure relief component 6, the pressure relief component 6 can rupture along at least a portion of the first groove 61 to release the pressure inside the battery cell 10. It is understood that when the pressure of the battery cell 10 is released, the pressure relief component 6 can rupture along the entire first groove 61 or along a portion of the first groove 61 to release the pressure inside the battery cell 10. The first groove 61 can be formed in a variety of ways, such as stamping, milling, etc. The groove segment 611 in the first groove 61 can be one or more, and the groove segment 611 can extend along a straight line or an arc. The cross-sectional shape of the groove segment 611 can be various, such as rectangular, trapezoidal, etc., and the cross-sectional shape of the groove segment 611 is perpendicular to the extension direction of the groove segment 611. The first groove 61 can have various shapes. For example, the first groove 61 is a groove extending along a straight line or an arc trajectory, and the groove segment 611 in the first groove 61 can be one. For another example, the first groove 61 includes multiple groove segments 611, and the multiple groove segments 611 can form a U-shape, H-shape, V-shape, Y-shape, X-shape, etc.

[0149] The minimum width of the groove bottom surface 6111 of the groove segment is the minimum dimension of the groove bottom surface 6111 in the width direction of the groove segment 611. Taking the example of the groove bottom surface 6111 of the groove segment having two opposite edge lines along the width direction of the groove segment 611, the minimum distance between the two edge lines along the width direction of the groove segment 611 is the minimum width of the groove bottom surface 6111 of the groove segment. The groove bottom surface 6111 of the groove segment and the two opposite groove side surfaces of the groove segment 611 are connected to form two edge lines respectively. The groove bottom surface 6111 of the groove segment and the groove side surface can be directly connected to form a sharp angle in the connection area; the groove bottom surface 6111 of the groove segment and the groove side surface can also be indirectly connected through an arc surface to form a rounded corner in the connection area. The minimum residual thickness of the groove segment 611 is the minimum thickness of the remaining portion after the pressure relief component 6 is provided with the groove segment 611. The remaining portion can be the groove bottom wall of the groove segment 611, and the remaining portion can also be called a weak portion. The thickness of the bottom wall of the trough section 611 may be uniform or non-uniform. If the thickness of the bottom wall of the trough section 611 is non-uniform, the thickness of the thinnest position of the bottom wall of the trough section 611 is the minimum residual thickness of the trough section 611.

[0150] W×D1 is the area of ​​the minimum cross section of the weak portion, which is perpendicular to the extension direction of the slot section 611. W×D1 can be 0.005mm 2 , 0.008mm 2 , 0.01mm 2 , 0.02mm 2 , 0.05mm 2 , 0.08mm 2 , 0.09mm 2 , 0.1mm 2 , 0.11mm 2 , 0.12mm 2 Any point value or any range of values ​​between the two.

[0151] When measuring the minimum width W of the groove bottom surface 6111 of the groove segment and the minimum residual thickness D1 of the groove segment 611, the pressure relief component 6 can be cut in a direction perpendicular to the groove segment 611, and W and D1 can be measured on the cut surface. It should be noted that along the extension direction of the groove segment 611, if the end of the groove segment 611 has a rounded corner, W is the minimum width of the groove bottom surface 6111 of the groove segment in the non-rounded area of ​​the groove segment 611, that is, W is measured at the groove bottom surface 611 other than the rounded area of ​​the groove segment 611. Along the extension direction of the groove segment 611, if the end of the groove segment 611 has a chamfered corner, W is the minimum width of the groove bottom surface 6111 of the groove segment in the non-chamfered area of ​​the groove segment 611, that is, W is measured at the groove bottom surface 611 other than the chamfered area of ​​the groove segment 611.

[0152] As an example, in the embodiments shown in Figures 4 to 7, the shell 1 is in the shape of a rectangular parallelepiped, the thickness direction of the first wall portion 13 is parallel to the first direction X, the length direction of the first wall portion 13 is parallel to the second direction Y, and the width direction of the first wall portion 13 is parallel to the third direction Z.

[0153] In the embodiment of the present application, the pressure relief component 6 is provided with a first groove 61, so that the pressure relief component 6 can be split along at least a portion of the first groove 61 when the battery cell 10 is depressurized, thereby releasing the internal pressure of the battery cell 10. W×D1≥0.005mm 2, preventing the minimum width of the groove bottom surface 6111 of the groove segment from being too small, and the minimum residual thickness of the groove segment 611 from being too small. This reduces the risk of insufficient fatigue strength in the area where the pressure relief component 6 is provided with the groove segment 611 due to the minimum width of the groove bottom surface 6111 being too small, improves the fatigue strength of the area where the pressure relief component 6 is provided with the groove segment 611, reduces the risk of the pressure relief component 6 prematurely cracking along the groove segment 611 during normal use of the battery cell 10, and increases the service life of the battery cell 10. W×D1≤0.12mm 2 , it will not cause the minimum width of the groove bottom surface 6111 of the groove section to be too large, and the minimum residual thickness of the groove section 611 to be too large, thereby alleviating the situation where the strength of the area where the pressure relief component 6 is provided with the groove section 611 is too high due to the minimum width of the groove bottom surface 6111 of the groove section and the minimum residual thickness of the groove section 611 being too large, so that the pressure relief component 6 can be more timely cracked along the groove section 611 when the battery cell 10 is in thermal runaway, thereby improving the timeliness of the pressure relief of the battery cell 10, reducing the risk of explosion of the battery cell 10, and improving the reliability of the battery cell 10. Therefore, 0.005mm 2 ≤W×D1≤0.12mm 2 , taking into account both the service life requirements of the battery cell 10 during normal use and the reliability requirements of the battery cell 10 during thermal runaway.

[0154] In some embodiments, 0.01 mm 2 ≤W×D1≤0.05mm 2 .

[0155] W×D1 can be 0.01mm 2 , 0.012mm 2 , 0.015mm 2 , 0.018mm 2 , 0.02mm 2 , 0.022mm 2 , 0.025mm 2 , 0.028mm 2 , 0.03mm 2 , 0.032mm 2 , 0.035mm 2 , 0.038mm 2 , 0.04mm 2 , 0.042mm 2 , 0.045mm 2 , 0.048mm 2 , 0.05mm 2 Any point value or any range of values ​​between the two.

[0156] In this embodiment, W×D1≥0.01mm 2 , further improving the fatigue strength of the area where the pressure relief component 6 is provided with the groove section 611, further reducing the risk of the pressure relief component 6 prematurely cracking along the groove section 611 during normal use of the battery cell 10, and further improving the service life of the battery cell 10; W×D1≤0.05mm 2 , so that the pressure relief component 6 can be more timely ruptured along the groove section 611 when the battery cell 10 is in thermal runaway, further improving the timeliness of the pressure relief of the battery cell 10 and further reducing the risk of explosion of the battery cell 10.

[0157] In some embodiments, 0.05 mm ≤ W ≤ 0.5 mm.

[0158] W can be any point value of 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, or a range of values ​​between any two of them.

[0159] In this embodiment, W≥0.05mm, so that the minimum width of the groove bottom surface 6111 of the groove segment is not too small, thereby reducing the difficulty of forming the groove segment 611; W≤0.5mm, so that the minimum width of the groove bottom surface 6111 of the groove segment is not too large, thereby reducing the minimum residual thickness of the groove segment 611 is not too small. On the one hand, the risk of the pressure relief component 6 cracking along the groove segment 611 during the forming process of the groove segment 611 is reduced, thereby improving the forming yield of the pressure relief component 6. On the other hand, there is no need to process the groove bottom surface 6111 of the groove segment too wide, thereby reducing the forming force applied to the pressure relief component 6 during the forming process of the groove segment 611.

[0160] In some embodiments, 0.1 mm ≤ W ≤ 0.3 mm.

[0161] W can be any point value of 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, or 0.3mm, or a range value between any two of them.

[0162] In this embodiment, 0.1 mm ≤ W ≤ 0.3 mm, which can further reduce the difficulty of forming the groove section 611 and further reduce the risk of the pressure relief component 6 cracking along the groove section 611 during the forming process.

[0163] In some embodiments, 0.05 mm ≤ D1 ≤ 0.6 mm.

[0164] D1 can take any point value of 0.05mm, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, or a range of values ​​between any two of them.

[0165] In this embodiment, D1 is ≥ 0.05 mm, which prevents the minimum residual thickness of the groove segment 611 from being too small. This reduces the risk of the pressure relief component 6 cracking along the groove segment 611 during the forming process, thereby improving the forming yield of the pressure relief component 6. Furthermore, it eliminates the need to machine the groove bottom surface 6111 of the groove segment too wide, thereby reducing the forming force applied to the pressure relief component 6 during the forming process of the groove segment 611. D1 is ≤ 0.6 mm, which prevents the minimum residual thickness of the groove segment 611 from being too large, thereby eliminating the need to machine the groove bottom surface 6111 of the groove segment too narrow, thereby reducing the difficulty of forming the groove segment 611.

[0166] In some embodiments, 0.08 mm ≤ D1 ≤ 0.4 mm.

[0167] D1 can take any point value of 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, or 0.4mm, or a range between any two of them.

[0168] In this embodiment, the risk of the pressure relief component 6 being cracked along the groove segment 611 during the process of forming the groove segment 611 can be further reduced, and the difficulty of forming the groove segment 611 is further reduced.

[0169] In some embodiments, referring to Figures 8-11, Figure 8 is an assembly diagram of a battery cell 10 according to another embodiment of the present application; Figure 9 is a partial view of the housing 1 shown in Figure 8; Figure 10 is a CC cross-sectional view of the housing 1 shown in Figure 9; and Figure 11 is a partial enlarged view of point D in Figure 10. The first groove 61 defines at least one predetermined pressure relief area 63. The pressure relief component 6 is provided with a second groove 62. The second groove 62 is configured to guide at least a portion of the predetermined pressure relief area 63 to flip over, thereby opening at least a portion of the predetermined pressure relief area 63.

[0170] The second groove 62 is a rotation groove provided in the pressure relief component 6. When the pressure relief component 6 ruptures along at least a portion of the first groove 61, the second groove 62 guides the rotation of at least a portion of the predetermined pressure relief area 63. In other words, the second groove 62 facilitates the rotation of the predetermined pressure relief area 63, making it easier for the predetermined pressure relief area 63 to rotate toward the outside of the battery cell 10, thereby quickly opening the predetermined pressure relief area 63. The second groove 62 can guide the rotation of the predetermined pressure relief area 63 in its entirety or only in a portion. During the pressure relief process of the battery cell 10, the pressure relief component 6 can rupture along at least a portion of the first groove 61, and generally does not rupture along the second groove 62. The minimum thickness of the remaining portion of the pressure relief component 6 in the area where the first groove 61 is provided can be smaller than the minimum thickness of the remaining portion of the pressure relief component 6 in the area where the second groove 62 is provided, making the area where the first groove 61 is provided easier to rupture than the area where the second groove 62 is provided. The second groove 62 can be formed in various ways, such as by stamping, milling, etc. The second groove 62 can have various shapes, such as a groove extending along an arc trajectory, or a groove extending along a straight trajectory. The cross-sectional shape of the second groove 62 can be various shapes, such as a rectangle, a trapezoid, etc.

[0171] The second groove 62 not only facilitates the flipping of the predetermined pressure relief area 63 but also provides a buffering function. The second groove 62 absorbs any excess material extruded during the molding of the first groove 61, reducing the risk of the material from the first groove 61 spreading to the surface of the housing 1 along the width of the second groove 62, thereby improving the surface smoothness of the housing 1 along the width of the second groove 62. When the housing 1 of the battery cell 10 is subjected to internal and external impact forces and deforms along the width of the second groove 62, the second groove 62 can absorb the deformation energy of the housing 1, reducing the impact of the expansion and deformation of the battery cell 10 along the width of the second groove 62 on the pressure relief component 6.

[0172] The second groove 62 and the first groove 61 may be directly connected, or they may not contact each other. The second groove 62 and the first groove 61 may be provided on the same surface of the pressure relief component 6 along the thickness direction of the first wall portion 13, or they may be provided on two opposing surfaces of the pressure relief component 6 along the thickness direction of the first wall portion 13. If the second groove 62 and the first groove 61 are directly connected, they may be provided on the same surface of the pressure relief component 6. If the second groove 62 and the first groove 61 do not contact each other, the projection of the second groove 62 and the projection of the first groove 61 along the thickness direction of the first wall portion 13 may partially overlap or may not overlap.

[0173] The predetermined pressure relief area 63 is the area defined by the first groove 61 of the pressure relief component 6. The predetermined pressure relief area 63 defined by the first groove 61 can be one or more. The predetermined pressure relief area 63 can be opened when the pressure relief component 6 is cracked along the first groove 61. The predetermined pressure relief area 63 and the second groove 62 can correspond one to one, that is, each predetermined pressure relief area 63 is provided corresponding to one second groove 62. It is also possible that each predetermined pressure relief area 63 is provided corresponding to multiple second grooves 62. The predetermined pressure relief area 63 can be triangular, rectangular, trapezoidal, semicircular, etc. In this embodiment, the shape of the first groove 61 can be various. For example, the first groove 61 is a groove extending in an arc trajectory; for another example, the first groove 61 includes multiple groove segments 611, and the multiple groove segments 611 can form a U-shape, an H-shape, a V-shape, a Y-shape, an X-shape, etc. In the embodiment shown in FIG9 , the first groove 61 is an H-shaped structure, and there are two predetermined pressure relief areas 63 . The predetermined pressure relief areas 63 are roughly rectangular structures. The two shaded portions shown in FIG9 are the two predetermined pressure relief areas 63 .

[0174] The second groove 62 assists the predetermined pressure relief area 63 in flipping, making it easier for the predetermined pressure relief area 63 to flip, reducing the difficulty of flipping the predetermined pressure relief area 63, and allowing the predetermined pressure relief area 63 to open more quickly during the process of the pressure relief component 6 splitting along the first groove 61, thereby improving the opening rate of the predetermined pressure relief area 63.

[0175] In some embodiments, referring to FIG. 11 , the minimum residual thickness of the second groove 62 is D2 , satisfying: D1 < D2 .

[0176] The minimum residual thickness of the second groove 62 is the minimum thickness of the remaining portion of the pressure relief component 6 after the second groove 62 is provided. The remaining portion may be the bottom wall of the second groove 62. The thickness of the bottom wall of the second groove 62 may be uniform or uneven. If the thickness of the bottom wall of the second groove 62 is uneven, the thickness of the thinnest portion of the bottom wall of the second groove 62 is the minimum residual thickness of the second groove 62.

[0177] In this embodiment, D1<D2, so that the strength of the area where the groove section 611 of the pressure relief component 6 is set is less than the strength of the area where the second groove 62 of the pressure relief component 6 is set, so that the pressure relief component 6 can preferentially break along the first groove 61 to achieve rapid opening of the predetermined pressure relief area 63.

[0178] In some embodiments, referring to FIG. 11 , along the thickness direction of the first wall portion 13 , the maximum groove depth of the groove section 611 is H1 , and the maximum groove depth of the second groove 62 is H2 , satisfying: H2 < H1 .

[0179] The maximum distance between the notch of the groove segment 611 and its bottom surface 6111 along the thickness direction of the first wall portion 13 is the maximum groove depth of the first groove 61. The maximum distance between the notch of the second groove 62 and its bottom surface 623 along the thickness direction of the first wall portion 13 is the maximum groove depth of the second groove 62. Along the thickness direction of the first wall portion 13, the pressure relief component 6 may have opposing first and second surfaces 64, 65. The first groove 61 may be provided on one of the first and second surfaces 64, 65, and the second groove 62 may be provided on the other of the first and second surfaces 64, 65. Alternatively, both the first and second grooves 61, 62 may be provided on either the first or second surface 64, 65.

[0180] As an example, the first surface 64 is parallel to the second surface 65 , the distance between the first surface 64 and the second surface 65 is D, the thickness of the pressure relief component 6 is D, and D= D1 + H1 = D2 + H2 .

[0181] In this embodiment, by setting the maximum depth of the groove segment 611 to be greater than the maximum depth of the second groove 62, the minimum residual thickness of the groove segment 611 is facilitated to be smaller than the minimum residual thickness of the second groove 62. During the production process, the depth of the groove segment 611 can be machined deeper than the depth of the second groove 62, thereby achieving a minimum residual thickness of the groove segment 611 smaller than the minimum residual thickness of the second groove 62.

[0182] In some embodiments, along the thickness direction of the first wall portion 13 , the maximum groove depth of the groove section 611 is H1 , the thickness of the pressure relief component 6 is D, and 0.16≤H1 / D<1.

[0183] H1 / D can take any point value among 0.16, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.62, 0.65, 0.68, 0.7, 0.72, 0.75, 0.78, 0.8, 0.82, 0.85, 0.88, 0.9, 0.92, 0.95, 0.98, 0.99, etc., or a range of values ​​between any two of them.

[0184] It is understandable that if the pressure relief component 6 and the first wall portion 13 are integrally formed, the first wall portion 13 can serve as the pressure relief component 6 , and the thickness of the pressure relief component 6 is the same as the thickness of the first wall portion 13 .

[0185] In this embodiment, 0.16≤H1 / D<1, so that the maximum groove depth of the groove section 611 accounts for a small proportion of the thickness of the pressure relief component 6, and the bursting pressure of the battery cell 10 is not too high, which is conducive to improving the timeliness of the pressure relief of the battery cell 10.

[0186] In some embodiments, 0.4 mm ≤ H1 ≤ 2 mm, and 0.8 mm ≤ D ≤ 2.5 mm.

[0187] H1 can take any point value among 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, etc., or any range value between any two of them.

[0188] D can be any point value among 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, 2.05mm, 2.1mm, 2.15mm, 2.2mm, 2.25mm, 2.3mm, 2.35mm, 2.4mm, 2.45mm, 2.5mm, etc., or a range value between any two of them.

[0189] In some embodiments, referring to FIG. 9 , the pressure relief component 6 is provided with a plurality of second grooves 62 , the first groove 61 defines a plurality of predetermined pressure relief areas 63 , and each predetermined pressure relief area 63 is provided corresponding to at least one second groove 62 .

[0190] There may be two, three, four, or more second grooves 62, and there may be two, three, four, or more predetermined pressure relief areas 63 defined by the first groove 61. Each predetermined pressure relief area 63 may be provided corresponding to at least one second groove 62, that is, each predetermined pressure relief area 63 may be provided corresponding to one second groove 62, or may be provided corresponding to multiple second grooves 62.

[0191] In this embodiment, the first groove 61 defines a plurality of predetermined pressure relief areas 63. When the battery cell 10 thermally runs away, the plurality of predetermined pressure relief areas 63 can be opened. When the total pressure relief area of ​​the pressure relief component 6 is constant, the opening rate of the predetermined pressure relief areas 63 can be increased, and pressure relief can be achieved more quickly.

[0192] 9 , in some embodiments, the first groove 61 includes a plurality of groove segments 611, which define two predetermined pressure relief areas 63. The plurality of groove segments 611 include a first groove segment 611a, which is spaced apart from the second groove 62 along the width direction of the second groove 62. The two predetermined pressure relief areas 63 are respectively located on either side of the first groove segment 611a.

[0193] The first groove 61 may be two, three, four, or more. The first groove section 611a may be one of the multiple groove sections 611. The first groove section 611a is the groove section 611 in the first groove 61 that separates the two predetermined pressure relief areas 63. The areas of the two predetermined pressure relief areas 63 may be equal or unequal. The first groove section 611a and the second groove 62 are arranged along the width of the second groove 62. The second groove 62 and the first groove section 611a may be parallel, or the extension line of the second groove 62 may intersect the extension line of the first groove section 611a.

[0194] As an example, in the embodiment shown in Figure 9, the width direction of the second groove 62 is parallel to the third direction Z, there are three groove sections 611 in the first groove 61, and the three groove sections 611 constitute an H-shaped structure. The first groove section 611a and the second groove 62 both extend along a straight line trajectory, the first groove section 611a is parallel to the second groove 62, the second groove 62 corresponds one-to-one to the predetermined pressure relief area 63, the distances between the two second grooves 62 and the first groove section 611a are equal, and the two predetermined pressure relief areas 63 are symmetrically arranged on both sides of the first groove section 611a, so that the areas of the two predetermined pressure relief areas 63 are equal.

[0195] In this embodiment, the multiple groove sections 611 of the first groove 61 define two predetermined pressure relief areas 63, so that the first groove section 611a of the first groove 61 is located between the two predetermined pressure relief areas 63. After the pressure relief component 6 is split along the first groove section 611a, the two predetermined pressure relief areas 63 can be opened in a split manner to relieve pressure when the battery cell 10 is depressurized, so that the two predetermined pressure relief areas 63 can be opened quickly, which is beneficial to improving the pressure relief rate of the battery cell 10.

[0196] In some embodiments, referring to FIG. 9 to FIG. 11 , along the thickness direction of the first wall portion 13 , the projection of the second groove 62 does not overlap with the projection of the first groove 61 .

[0197] Along the thickness direction of the first wall portion 13, the projection of the extended line of the second groove 62 may be connected to the projection of the first groove 61, or the projection of the extended line of the first groove 61 may be connected to the projection of the second groove 62, or the projection of the extended line of the first groove 61 may be connected to the projection of the extended line of the second groove 62. The second groove 62 and the first groove 61 may be arranged on the same side of the pressure relief component 6 in the thickness direction of the first wall portion 13, for example, the second groove 62 and the first groove 61 may both be arranged on the first surface 64 or the second surface 65 of the pressure relief component 6. The second groove 62 and the first groove 61 may also be arranged on different sides of the pressure relief component 6 in the thickness direction of the first wall portion 13, for example, the first groove 61 may be arranged on one of the first surface 64 and the second surface 65 of the pressure relief component 6, and the second groove 62 may be arranged on the other.

[0198] In this embodiment, the projection of the second groove 62 along the thickness direction of the first wall portion 13 does not overlap with the projection of the first groove 61 along the thickness direction of the first wall portion 13, which can reduce the mutual influence between the first groove 61 and the second groove 62 during the processing process and reduce the risk of the first groove 61 and the second groove 62 being connected to each other during the processing.

[0199] In some embodiments, please continue to refer to FIG. 9 to FIG. 11 , along the width direction of the second groove 62 , the second groove 62 and the first groove 61 are spaced apart.

[0200] The second groove 62 is spaced apart from the first groove 61 along the width direction of the second groove 62. That is, the projection of the second groove 62 along the thickness direction of the first wall portion 13 and the projection of the first groove 61 along the thickness direction of the first wall portion 13 are spaced apart a certain distance along the width direction of the second groove 62. In this embodiment, the second groove 62 and the first groove 61 can be located on the same side of the pressure relief component 6 in the thickness direction of the first wall portion 13, or they can be located on opposite sides of the pressure relief component 6 in the thickness direction of the first wall portion 13. It is understood that the projection of the second groove 62 along the thickness direction of the first wall portion 13 and the projection of the first groove 61 along the thickness direction of the first wall portion 13 are spaced apart along the width direction of the second groove 62.

[0201] As an example, in the embodiment shown in FIG10 , the housing 1 further includes a second wall portion 14 and a third wall portion 15 . The second wall portion 14 and the third wall portion 15 are disposed opposite each other along the width direction of the second groove 62 . The first wall portion 13 connects the first wall portion 13 and the third wall portion 15 . The first wall portion 13 serves as the pressure relief component 6 . The first wall portion 13 is provided with two second grooves 62 . Along the width direction of the second groove 62 , one second groove 62 is located between the first groove 61 and the second wall portion 14 , and the other second groove 62 is located between the first groove 61 and the third wall portion 15 .

[0202] In this embodiment, the second groove 62 and the first groove 61 are spaced apart along the width direction of the second groove 62, so that the projection of the second groove 62 along the thickness direction of the first wall portion 13 and the projection of the first groove 61 along the thickness direction of the first wall portion 13 do not overlap. On the one hand, the mutual influence between the first groove 61 and the second groove 62 during the processing can be reduced. On the other hand, the residual stress between the area where the first groove 61 of the pressure relief component 6 is set and the area where the second groove 62 of the pressure relief component 6 is set can be reduced, and the risk of the cracks generated by the cracking of the pressure relief component 6 along the first groove 61 spreading to the second groove 62, thereby causing the pressure relief component 6 to crack along the second groove 62, can be reduced.

[0203] In the above embodiment, the second groove 62 is spaced apart from the first groove 61 along the width direction of the second groove 62, so that the projection of the first groove 61 along the thickness direction of the first wall portion 13 does not lie within the predetermined pressure relief zone 63. In other embodiments, part or all of the projection of the first groove 61 along the thickness direction of the first wall portion 13 may lie within the predetermined pressure relief zone 63.

[0204] In some embodiments, referring to FIG. 9 , along the thickness direction of the first wall portion 13 , two ends of the projection of the second groove 62 along the extension direction respectively extend beyond two ends of the projection of the first groove 61 .

[0205] Along the thickness direction of the first wall portion 13, the projection of the second groove 62 has two opposite ends in the extension direction, namely a first end 621 and a second end 622. The two ends of the projection of the second groove 62 along the extension direction respectively extend beyond the two ends of the projection of the first groove 61. That is, the two ends of the projection of the first groove 61 are located between the first end 621 and the second end 622 along the extension direction of the projection of the second groove 62. The extension direction of the projection of the second groove 62 along the thickness direction of the first wall portion 13 is parallel to the extension direction of the second groove 62. As an example, along the extension direction of the second groove 62, the length of the second groove 62 is greater than the length of the first groove 61 (the maximum span of the first groove 61 along the extension direction of the second groove 62).

[0206] As an example, in the embodiment shown in FIG. 9 , the extension direction of the second groove 62 is parallel to the second direction Y.

[0207] In this embodiment, the projection of the second groove 62 along the thickness direction of the first wall portion 13 extends beyond the projection of the first groove 61 along the thickness direction of the first wall portion 13 at both ends along the extension direction, making the second groove 62 longer and enhancing the second groove 62's effect of assisting the flipping of the predetermined pressure relief area 63. Furthermore, this structure can enhance the second groove 62's ability to separate the surface of the battery cell 10 in the width direction of the second groove 62 (the outer surface of the second wall portion 14 or the outer surface of the third wall portion 15) from the first groove 61, improve the second groove 62's ability to absorb excess material extruded during the molding of the first groove 61, and improve the flatness of the surface of the battery cell 10 in the width direction of the second groove 62. Furthermore, it can enhance the second groove 62's ability to block deformation energy of the battery cell 10 when subjected to internal or external impact forces, thereby reducing the impact of battery cell 10 expansion on the pressure relief component 6.

[0208] In other embodiments, along the thickness direction of the first wall portion 13 , the projection of the second groove 62 may be located between two ends of the projection of the first groove 61 .

[0209] In some embodiments, please continue to refer to Figures 10 and 11. Along the thickness direction of the first wall portion 13, the pressure relief component 6 has a first surface 64 and a second surface 65 arranged opposite to each other. The first groove 61 is arranged on the first surface 64, and the second groove 62 is arranged on the second surface 65.

[0210] One of the first surface 64 and the second surface 65 can be the outer surface of the pressure relief component 6, and the other can be the inner surface of the pressure relief component 6. The outer surface of the pressure relief component 6 faces the exterior of the battery cell 10, and the inner surface of the pressure relief component 6 faces the interior of the battery cell 10. The first surface 64 and the second surface 65 can be planes. The first surface 64 and the second surface 65 can be parallel or arranged at a non-zero angle. The first groove 61 is provided on the first surface 64, that is, the first groove 61 is recessed from the first surface 64 toward the second surface 65, and the notch of the first groove 61 is formed on the first surface 64. The second groove 62 is provided on the second surface 65, and the second groove 62 is recessed from the second surface 65 toward the first surface 64, and the notch of the second groove 62 is formed on the second surface 65. It is understood that the groove section 611 is provided on the first surface 64, and the groove section 611 is recessed from the first surface 64 toward the second surface 65.

[0211] In this embodiment, the first groove 61 and the second groove 62 are respectively provided with a first surface 64 and a second surface 65, so that the first groove 61 and the second groove 62 are respectively located on both sides of the pressure relief component 6 in the thickness direction, so as to facilitate the processing of the first groove 61 and the second groove 62 on both sides of the pressure relief component 6, which is beneficial to reduce the mutual influence of the first groove 61 and the second groove 62 during the processing.

[0212] In some embodiments, referring to FIG. 10 and FIG. 11 , the first surface 64 is the surface of the pressure relief component 6 facing the outside of the housing 1 , and the second surface 65 is the surface of the pressure relief component 6 facing the inside of the housing 1 .

[0213] It is understood that the first surface 64 is the outer surface of the pressure relief component 6, and the second surface 65 is the inner surface of the pressure relief component 6. In the embodiment where the first wall portion 13 serves as the pressure relief component 6, the first surface 64 is the outer surface of the first wall portion 13, and the second surface 65 is the inner surface of the first wall portion 13.

[0214] The first surface 64 is the surface of the pressure relief component 6 facing the exterior of the housing 1, allowing the first groove 61 to be positioned on the exterior of the pressure relief component 6. This facilitates the formation of the first groove 61 on the exterior of the battery cell 10, thereby reducing the difficulty of forming the first groove 61 and improving the production efficiency of the battery cell 10. The second surface 65 is the surface of the pressure relief component 6 facing the interior of the housing 1, allowing the second groove 62 to be positioned on the interior of the pressure relief component 6. This prevents the second groove 62 from abutting against the opposing widthwise sides of the pressure relief component 6 during the outward flipping and opening of the predetermined pressure relief area 63, thereby increasing the opening area of ​​the predetermined pressure relief area 63. Furthermore, the second groove 62 is not exposed to the exterior of the battery cell 10, reducing the risk of oxidation and corrosion of the pressure relief component 6 in the region of the second groove 62.

[0215] In some embodiments, along the thickness direction of the first wall portion 13 , the pressure relief component 6 has a second surface 65 facing the interior of the housing 1 , and the second groove 62 is provided on the second surface 65 .

[0216] The second surface 65 is the inner surface of the pressure relief component 6. When the second groove 62 is provided on the second surface 65, the first groove 61 can be provided on the first surface 64, and the first groove 61 can also be provided on the second surface 65.

[0217] In this embodiment, the second groove 62 is arranged on the surface of the pressure relief component 6 facing the interior of the shell 1, so that the second groove 62 is arranged on the inner side of the pressure relief component 6. On the one hand, during the process of the predetermined pressure relief area 63 being flipped outward and opened, the two opposite side surfaces of the second groove 62 in the width direction are not easy to abut against each other, which is beneficial to increase the opening area of ​​the predetermined pressure relief area 63; on the other hand, the second groove 62 is not exposed to the outside of the battery cell 10, reducing the risk of oxidation and corrosion of the pressure relief component 6 in the second groove 62 area.

[0218] In some embodiments, referring to FIG. 9 , the first wall portion 13 is a rectangular wall portion, and the first groove 61 and the second groove 62 are arranged along the width direction of the first wall portion 13 .

[0219] The housing 1 may be in the shape of a rectangular parallelepiped, and the first wall 13 may be any rectangular wall in the housing 1. The first wall 13 is a rectangular wall, that is, when viewed along the thickness direction of the first wall 13, the first wall 13 is generally in the shape of a rectangle. The length of the first wall 13 is greater than its width.

[0220] The first groove 61 and the second groove 62 are arranged along the width direction of the first wall portion 13. The first groove 61 and the second groove 62 can be spaced apart along the width direction of the first wall portion 13, or the projection of the first groove 61 along the thickness direction of the first wall portion 13 and the projection of the second groove 62 along the thickness direction of the first wall portion 13 are just connected in the width direction of the first wall portion 13.

[0221] As an example, the first groove 61 and the second groove 62 are spaced apart from each other along the width direction of the first wall portion 13 , and the width direction of the first wall portion 13 is parallel to the width direction of the second groove 62 .

[0222] In this embodiment, the first wall portion 13 is a rectangular wall portion, and the first groove 61 and the second groove 62 are arranged along the width direction of the first wall portion 13. This allows the second groove 62 to be closer to the edge of the first wall portion 13 in the width direction of the first wall portion 13. This provides the pressure relief member 6 with greater strength in the area where the second groove 62 is provided, thereby reducing the risk of the pressure relief member 6 cracking along the second groove 62 when the battery cell 10 releases pressure. Furthermore, during normal use of the battery cell 10, the battery cell 10 expands more in the width direction of the first wall portion 13 than in the length direction of the first wall portion 13. This expansion of the battery cell 10 in the width direction of the first wall portion 13 has a greater impact on the pressure relief member 6. Since the first groove 61 and the second groove 62 are arranged along the width direction of the first wall portion 13, the second groove 62 can effectively absorb the deformation energy of the battery cell 10 when it expands and deforms in the width direction of the first wall portion 13, thereby reducing the impact of the expansion of the battery cell 10 in the width direction of the first wall portion 13 on the pressure relief member 6.

[0223] In some embodiments, the second groove 62 extends along a straight line. The second groove 62 is a straight groove with a simple structure and is easy to process and form.

[0224] In some embodiments, please refer to FIG12, which is a partial enlarged view of point E in FIG11. Along the thickness direction of the first wall portion 13, the pressure relief component 6 has a first surface 64 and a second surface 65 disposed opposite each other. The groove segment 611 includes a plurality of grooves sequentially arranged from the first surface 64 toward the second surface 65. In two adjacent grooves, the primary groove farther from the first surface 64 is arranged at the groove bottom surface of the primary groove closer to the first surface 64. The primary groove furthest from the first surface 64 among the multi-stage grooves is the first-stage groove 6112. The minimum residual thickness of the first-stage groove 6112 is the minimum residual thickness of the groove segment 611, and the groove bottom surface of the first-stage groove 6112 is the groove bottom surface 6111 of the groove segment.

[0225] The groove segment 611 can be a two-stage groove, a three-stage groove, a four-stage groove, a five-stage groove, or the like. It is understood that the groove segment 611 is a stepped groove. The groove width of each stage gradually decreases as it moves from the first surface 64 to the second surface 65. As shown in FIG12 , taking the groove segment 611 as a two-stage groove as an example, the two stages are a first-stage groove 6112 and a second-stage groove. During machining, the second-stage groove with a larger width can be machined first on the first surface 64, and then the first-stage groove 6112 with a smaller width can be machined on the bottom surface of the second-stage groove.

[0226] The first-stage groove 6112 is the first-stage groove farthest from the first surface 64 in the groove segment 611. The bottom surface of the first-stage groove 6112 is the same as the bottom surface 6111 of the groove segment. The minimum residual thickness of the first-stage groove 6112 is the same as the minimum residual thickness of the groove segment 611. The maximum distance between the bottom surface of the first-stage groove 6112 and the first surface 64 is equal to the maximum groove depth of the groove segment 611.

[0227] In this embodiment, by setting the groove section 611 to be arranged as a multi-level groove along the thickness direction of the first wall portion 13, when forming the groove section 611, each level of groove can be processed one by one along the direction from the first surface 64 to the second surface 65, thereby reducing the forming depth of each level of groove, reducing the forming force exerted on the pressure relief component 6 when forming the first groove 61, and reducing the risk of the pressure relief component 6 being damaged when forming the first groove 61.

[0228] In some embodiments, referring to Figures 13 and 14, Figure 13 is a partial view of a housing 1 provided in other embodiments of the present application; Figure 14 is a cross-sectional view taken along line FF of the housing 1 shown in Figure 13. The first groove 61 includes a plurality of groove segments 611, each of which includes a first groove segment 611a and a second groove segment 611b. The first groove segment 611a is connected to the second groove segment 611b, and the first groove segment 611a and the second groove segment 611b together define at least one predetermined pressure relief area 63.

[0229] The first slot segment 611a and the second slot segment 611b are two slot segments 611 in the first groove 61. The first slot segment 611a and the second slot segment 611b can jointly define one or more predetermined pressure relief zones 63. The first slot segment 611a and the second slot segment 611b can be linear slots extending along a linear trajectory, or non-linear slots extending along a non-linear trajectory, such as arcuate slots extending along an arcuate trajectory. If both the first slot segment 611a and the second slot segment 611b extend along a linear trajectory, the first slot segment 611a and the second slot segment 611b can be arranged at an acute angle, a right angle, or an obtuse angle. The first slot segment 611a and the second slot segment 611b can be connected end-to-end to form a V-shaped, L-shaped, or other structure. The first slot segment 611a and the second slot segment 611b can define a predetermined pressure relief zone 63. The first slot section 611 a and the second slot section 611 b may also be cross-arranged to form an X-shaped structure. The first slot section 611 a and the second slot section 611 b may define four predetermined pressure relief areas 63 .

[0230] As an example, in the embodiments shown in Figures 13 and 14, the first slot segment 611a and the second slot segment 611b are connected to form a V-shaped structure. The first slot segment 611a and the second slot segment 611b define a predetermined pressure relief zone 63. The first groove 61 is provided on the first surface 64, and the second groove 62 is provided on the second surface 65. The line connecting the end of the first slot segment 611a away from the second slot segment 611b and the end of the second slot segment 611b away from the first slot segment 611a within the first surface 64 is a first line U. The first line U, the second slot segment 611b, and the second slot segment 611b are connected end to end to enclose the predetermined pressure relief zone 63. In Figure 13, the triangular shaded portion represents the predetermined pressure relief zone 63.

[0231] In this embodiment, at least one predetermined pressure relief area 63 is defined by the first groove section 611a and the second groove section 611b. The first groove 61 of this structure has a simple structure. The stress at the connection position between the first groove section 611a and the second groove section 611b is more concentrated and weaker. Therefore, when the battery cell 10 thermally runs away, the pressure relief component 6 can quickly split from the first groove section 611a and the second groove section 611b after the connection position between the first groove section 611a and the second groove section 611b is split, so that the predetermined pressure relief area 63 opens more quickly and the pressure is relieved in time.

[0232] In some embodiments, please continue to refer to Figures 9 and 10. The first groove 61 includes a plurality of groove segments 611, and the plurality of groove segments 611 include a first groove segment 611a, a second groove segment 611b and a third groove segment 611c. The second groove segment 611b and the third groove segment 611c are arranged opposite to each other, and the first groove segment 611a connects the second groove segment 611b and the third groove segment 611c. The first groove segment 611a, the second groove segment 611b and the third groove segment 611c jointly define at least one predetermined pressure relief area 63.

[0233] The first slot segment 611a, the second slot segment 611b and the third slot segment 611c can jointly define a predetermined pressure relief area 63 or multiple predetermined pressure relief areas 63. The first slot segment 611a, the second slot segment 611b and the third slot segment 611c are three slot segments 611 in the first groove 61. The first slot segment 611a, the second slot segment 611b and the third slot segment 611c can be linear slots extending along a linear trajectory, or non-linear slots extending along a non-linear trajectory, for example, arcuate slots extending along an arc trajectory. If the first slot segment 611a, the second slot segment 611b and the third slot segment 611c all extend along a straight line, the first slot segment 611a and the second slot segment 611b can be set at an acute angle, a right angle, or an obtuse angle, the first slot segment 611a and the second slot segment 611b can be set at an acute angle, a right angle, or an obtuse angle, the second slot segment 611b and the third slot segment 611c can be set in parallel, or the extension line of the second slot segment 611b can intersect with the extension line of the third slot segment 611c.

[0234] The first slot segment 611a connects the second slot segment 611b and the third slot segment 611c. This can be done by connecting the first slot segment 611a at both ends to the second slot segment 611b and the third slot segment 611c, respectively. Alternatively, at least one of the second slot segment 611b and the third slot segment 611c is connected to a position offset from the end of the first slot segment 611a, such that at least one of the second slot segment 611b and the third slot segment 611c is located between the two ends of the first slot segment 611a. The second slot segment 611b can connect to the first slot segment 611a at one end or between the two ends of the second slot segment 611b. The third slot segment 611c can connect to the first slot segment 611a at one end or between the two ends of the third slot segment 611c. The first slot segment 611a, the second slot segment 611b, and the third slot segment 611c can form a U-shaped, N-shaped, or H-shaped structure. If the first slot section 611a, the second slot section 611b, and the third slot section 611c form a U-shaped structure, the first slot section 611a, the second slot section 611b, and the third slot section 611c jointly define a predetermined pressure relief area 63. If the first slot section 611a, the second slot section 611b, and the third slot section 611c form an N-shaped or H-shaped structure, the first slot section 611a, the second slot section 611b, and the third slot section 611c jointly define two predetermined pressure relief areas 63.

[0235] As an example, in the embodiments shown in Figures 9 and 10, the first groove section 611a, the second groove section 611b and the third groove section 611c form an H-shaped structure, there are two predetermined pressure relief areas 63, the first groove 61 is provided on the first surface 64, the second groove 62 is provided on the second surface 65, and the line connecting one end of the second groove section 611b and one end of the third groove section 611c in the first surface 64 forms a first connecting line U, and the line connecting the other end of the second groove section 611b and the other end of the third groove section 611c in the first surface 64 forms a first connecting line U. The line forms another first connecting line U, the first slot segment 611a is located between the two first connecting lines U, a part of the second slot segment 611b, the first slot segment 611a, a part of the third slot segment 611c and a first connecting line U are connected end to end to enclose a predetermined pressure relief area 63, and another part of the second slot segment 611b, the first slot segment 611a, another part of the third slot segment 611c and another first connecting line U are connected end to end to enclose another predetermined pressure relief area 63. The two shaded parts shown in Figure 9 are the two predetermined pressure relief areas 63.

[0236] In this embodiment, the first slot section 611a connects the second slot section 611b and the third slot section 611c, making the intersection of the first and second slot sections 611a, 611b, and the connection between the first and third slot sections 611a, 611c, weaker, making them more susceptible to rupturing and opening the predetermined pressure relief area 63 for pressure relief. The opposing arrangement of the second and third slot sections 611b, 611c, further increases the open area of ​​the predetermined pressure relief area 63, thereby increasing the pressure relief area of ​​the battery cell 10 and improving the pressure relief rate of the battery cell 10.

[0237] In some embodiments, the connection position between the second slot segment 611b and the first slot segment 611a deviates from the two ends of the second slot segment 611b, and the connection position between the third slot segment 611c and the first slot segment 611a deviates from the two ends of the third slot segment 611c, so that a predetermined pressure relief area 63 is formed on both sides of the first slot segment 611a.

[0238] The connection between the second slot segment 611b and the first slot segment 611a is offset from the ends of the second slot segment 611b. That is, the connection between the second slot segment 611b and the first slot segment 611a is not located at either end of the second slot segment 611b. Along the extension direction of the second slot segment 611b, the connection between the second slot segment 611b and the first slot segment 611a is located between the ends of the second slot segment 611b. The connection between the second slot segment 611b and the first slot segment 611a can be located at the midpoint of the second slot segment 611b or offset from the midpoint of the second slot segment 611b.

[0239] The connection between the third slot segment 611c and the first slot segment 611a is offset from the ends of the third slot segment 611c. That is, the connection between the third slot segment 611c and the first slot segment 611a is not located at either end of the third slot segment 611c. Along the extension direction of the third slot segment 611c, the connection between the third slot segment 611c and the first slot segment 611a is located between the ends of the third slot segment 611c. The connection between the third slot segment 611c and the first slot segment 611a can be located at the midpoint of the third slot segment 611c or offset from the midpoint of the third slot segment 611c.

[0240] In this embodiment, the connection position of the second groove section 611b and the first groove section 611a deviates from the two ends of the second groove section 611b, and the connection position of the third groove section 611c and the first groove section 611a deviates from the two ends of the third groove section 611c, so that the first groove section 611a of the first groove 61 is located between the two predetermined pressure relief areas 63. After the pressure relief component 6 is split along the first groove section 611a, the two predetermined pressure relief areas 63 can be opened in a split manner to relieve pressure when the battery cell 10 is relieved of pressure, so that the two predetermined pressure relief areas 63 can be opened quickly, which is beneficial to improving the pressure relief rate of the battery cell 10.

[0241] In some embodiments, the first slot segment 611a extends along a straight line or an arcuate trajectory; and / or, the second slot segment 611b extends along a straight line or an arcuate trajectory; and / or, the third slot segment 611c extends along a straight line or an arcuate trajectory.

[0242] As an example, in the embodiment shown in FIG. 9 , the first slot segment 611 a , the second slot segment 611 b and the third slot segment 611 c all extend along straight trajectories, and the second slot segment 611 b and the third slot segment 611 c are both perpendicular to the first slot segment 611 a .

[0243] If the first groove section 611a extends along a straight path, it is a straight groove, which reduces the difficulty of forming the first groove section 611a. If the first groove section 611a extends along an arc path, it is an arc-shaped groove. The pressure relief component 6 is more likely to rupture along the first groove section 611a when the battery cell 10 releases pressure, thereby quickly opening the predetermined pressure relief area 63. If the second groove section 611b extends along a straight path, it is a straight groove, which reduces the difficulty of forming the second groove section 611b. If the second groove section 611b extends along an arc path, it is an arc-shaped groove. The pressure relief component 6 is more likely to rupture along the second groove section 611b when the battery cell 10 releases pressure, thereby quickly opening the predetermined pressure relief area 63. If the third groove section 611c extends along a straight path, it is a straight groove, thereby reducing the difficulty of forming the third groove section 611c. If the third groove section 611 c extends along an arc trajectory, the third groove section 611 c is an arc-shaped groove, and the pressure relief component 6 is more likely to break along the third groove section 611 c when the battery cell 10 releases pressure, thereby achieving faster opening of the predetermined pressure relief area 63 .

[0244] In some embodiments, please refer to Figures 15 and 16, Figure 15 is a partial view of the housing 1 provided in some embodiments of the present application; Figure 16 is a GG cross-sectional view of the housing 1 shown in Figure 15. The first groove 61 extends along an arc trajectory.

[0245] The central angle of the first groove 61 may be less than 15°, 30°, 45°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300°, 330°, etc.

[0246] As an example, in the embodiments shown in Figures 15 and 16, the first groove 61 is arranged on the first surface 64, the second groove 62 is arranged on the second surface 65, and the line connecting the two ends of the first groove 61 forms a first line U. The first groove 61 and the first line U are connected end to end to enclose a predetermined pressure relief area 63.

[0247] In this embodiment, the first groove 61 extends along an arc track. The first groove 61 is an arc-shaped groove. The first groove 61 of this structure only includes one groove segment 611 , which simplifies the structure of the first groove 61 .

[0248] In some embodiments, please refer to FIG17 , which is an exploded view of a housing 1 (an opening is formed at one end of the housing 11, and the end cap 12 is a pressure relief component 6) provided in some embodiments of the present application. The pressure relief component 6 is integrally formed with the first wall portion 13 (not shown in FIG17 ), so that the pressure relief component 6 is at least a portion of the first wall portion 13.

[0249] It is understood that the first groove 61 is provided in the first wall portion 13. In embodiments where the pressure relief component 6 is provided with the second groove 62, the second groove 62 is also provided in the first wall portion 13. A portion of the first wall portion 13 may serve as the pressure relief component 6, or the entire first wall portion 13 may serve as the pressure relief component 6, that is, the first wall portion 13 and the pressure relief component 6 are the same component. One of the first surface 64 and the second surface 65 of the pressure relief component 6 is the inner surface of the first wall portion 13, and the other is the outer surface of the first wall portion 13.

[0250] In this embodiment, the pressure relief component 6 is integrally formed with the first wall portion 13, so that the first groove 61 can be directly formed on the first wall portion 13, forming an integrated pressure relief structure with higher reliability, eliminating the installation process of the pressure relief component 6, and having better economy.

[0251] In some embodiments, please refer to Figure 18, which is an exploded view of a housing 1 (one end of the housing 11 is open, the end cap 12 forms a first wall portion 13, and the pressure relief component 6 is mounted on the first wall portion 13) provided in some embodiments of the present application. The pressure relief component 6 is provided separately from the first wall portion 13 and is mounted on the first wall portion 13.

[0252] The pressure relief component 6 and the housing 1 are separate components. The pressure relief component 6 can be manufactured separately and then mounted on the first wall portion 13. The pressure relief component 6 can be mounted on the first wall portion 13 by welding, riveting, bonding, or other methods. As an example, the first wall portion 13 is provided with a pressure relief hole 131. The pressure relief component 6 covers the pressure relief hole 131 and is welded to the first wall portion 13.

[0253] In this embodiment, the pressure relief component 6 is separately provided from the first wall portion 13 . The pressure relief component 6 is a component independent of the housing 1 . The pressure relief component 6 and the housing 1 can be produced and assembled separately, which reduces production difficulty and increases efficiency.

[0254] In some embodiments, the first groove 61 is stamped and formed on the pressure relief component 6 .

[0255] It is understood that the groove segment 611 is formed in the pressure relief component 6 by stamping. If the groove segment 611 is a single-stage groove structure, when forming the groove segment 611 in the pressure relief component 6, the first wall portion 13 can be stamped once to stamp out the groove segment 611 in the pressure relief component 6; if the groove segment 611 is a multi-stage groove structure, when forming the groove segment 611 in the pressure relief component 6, the pressure relief component 6 can be stamped multiple times, each time stamping out a single stage of groove, and finally forming the groove segment 611 after multiple stampings. It is understood that in the embodiment where the pressure relief component 6 and the first wall portion 13 are integrally formed, the groove segment 611 is stamped and formed in the first wall portion 13.

[0256] In this embodiment, the first groove 61 is stamped and formed on the pressure relief component 6 . The molding method of the first groove 61 is simple, which is beneficial to reducing the production cost of the battery cell 10 .

[0257] 17 and 18 , the housing 1 includes a shell 11 and an end cap 12 . The shell 11 has an opening at at least one end. The end cap 12 corresponds to the opening and closes the opening. At least one end cap 12 is a first wall portion 13 .

[0258] The housing 11 may have only one opening, for example, only one end of the housing 11 may have an opening; the housing 11 may also have multiple openings, for example, openings at both opposite ends of the housing 11. The number of end caps 12 is the same as the number of openings of the housing 11. It is understood that if the housing 11 has only one opening, there is only one end cap 12, which serves as the first wall portion 13; if the housing 11 has two openings, there are two end caps 12, and one end cap 12 may serve as the first wall portion 13, or both end caps 12 may serve as the first wall portion 13.

[0259] In an embodiment where the housing 11 is open at one end, the positive electrode terminal and the negative electrode terminal can be provided on the end cap 12, and the positive and negative electrode tabs can be formed at the end of the electrode assembly 2 facing the end cap 12, so as to facilitate electrical connection with the positive and negative electrode terminals, respectively. In an embodiment where openings are formed at both opposing ends of the housing 11, the positive electrode terminal can be provided at one end cap 12, and the negative electrode terminal can be provided at the other end cap 12, and the positive and negative electrode tabs can be formed at opposing ends of the electrode assembly 2, so as to facilitate electrical connection between the positive tab and the positive electrode terminal, and between the negative tab and the negative electrode terminal, respectively.

[0260] In the embodiment shown in FIG17 , an opening is formed at one end of the housing 11, and the end cap 12 forms a first wall portion 13 (not shown in FIG17 ). The first wall portion 13 serves as the pressure relief component 6. In the embodiment shown in FIG18 , an opening is formed at one end of the housing 11, and the end cap 12 forms a first wall portion 13. The pressure relief component 6 is mounted on the first wall portion 13.

[0261] In this embodiment, at least one end cover 12 in the housing 1 is the first wall portion 13, so that at least one end cover 12 has a pressure relief function, and the difficulty of forming the first groove 61 on the end cover 12 or installing the pressure relief component 6 is lower.

[0262] In some embodiments, please refer to Figures 19 and 20. Figure 19 is an exploded view of the housing 1 provided in some embodiments of the present application (an opening is formed at one end of the housing 11, the housing 11 includes a first wall portion 13, and the pressure relief component 6 is the first wall portion 13); Figure 20 is an exploded view of the housing 1 provided in some embodiments of the present application (an opening is formed at one end of the housing 11, the housing 11 includes a first wall portion 13, and the pressure relief component 6 is installed on the first wall portion 13). The housing 1 includes a housing 11 and an end cap 12. An opening is formed at least at one end of the housing 11. The end cap 12 corresponds to the opening one-to-one and closes the opening. At least one wall portion in the housing 11 is the first wall portion 13.

[0263] The housing 11 may have only one opening, for example, only one end of the housing 11 may have an opening; the housing 11 may also have multiple openings, for example, openings at both opposing ends of the housing 11. The number of end caps 12 is the same as the number of openings in the housing 11. It is understood that if the housing 11 has only one opening, there is one end cap 12; if the housing 11 has two openings, there are two end caps 12. In embodiments where the housing 11 has an opening at one end, the positive and negative electrode terminals may be disposed on the end cap 12, and the positive and negative tabs may be formed on the end of the electrode assembly 2 facing the end cap 12 to facilitate electrical connection with the positive and negative electrode terminals, respectively. In embodiments where openings are formed at both opposing ends of the housing 11, the positive electrode terminal may be disposed on one end cap 12, and the negative electrode terminal may be disposed on the other end cap 12. The positive and negative tabs may be formed on opposing ends of the electrode assembly 2 to facilitate electrical connection with the positive electrode terminal and with the negative electrode terminal, respectively. In the housing 11 , one wall portion may serve as the first wall portion 13 , or a plurality of wall portions may serve as the first wall portion 13 .

[0264] In this embodiment, at least one wall portion of the shell 11 in the outer casing 1 is a first wall portion 13, which provides the shell 11 with a pressure relief function. When the battery cell 10 releases pressure, the exhaust from the interior of the battery cell 10 is less likely to affect external components outside the end cap 12, reducing the risk of damage to external components by the exhaust. External components may include a busbar connected to the electrode terminal 3, a temperature detection component, a voltage detection component, etc. The exhaust includes, but is not limited to, electrolyte, dissolved or split positive and negative electrode sheets, separator fragments, high-temperature and high-pressure gases generated by the reaction, and flames.

[0265] In some embodiments, please continue to refer to Figures 19 and 20. Only one end of the shell 11 is formed with an opening, and the wall portion of the shell 11 opposite to the end cover 12 is the first wall portion 13.

[0266] As an example, the housing 11 is rectangular and further includes four side walls, which are arranged around the first wall portion 13. The four side walls and the first wall portion 13 together define the space inside the housing 11. In the embodiment shown in FIG19 , an opening is formed at one end of the housing 11. The wall portion of the housing 11 opposite the end cap 12 is the first wall portion 13, and the pressure relief component 6 is the first wall portion 13. In the embodiment shown in FIG20 , an opening is formed at one end of the housing 11. The wall portion of the housing 11 opposite the end cap 12 is the first wall portion 13, and the pressure relief component 6 is mounted on the first wall portion 13.

[0267] In this embodiment, the housing 11 is open at one end, simplifying the structure of the entire battery cell 10. The first wall 13 is the wall of the housing 11 opposite the end cap 12, and can achieve directional pressure relief from the bottom of the housing 11.

[0268] In some embodiments, please refer to FIG21 , which is an exploded view of a battery cell 10 provided in some other embodiments of the present application. Openings are formed at opposite ends of the housing 11 , and at least one wall portion of the housing 11 is a first wall portion 13 .

[0269] In the housing 11 , one wall portion or multiple walls may be the first wall portion 13 . The pressure relief component 6 may be the first wall portion 13 , or may be mounted on the first wall portion 13 .

[0270] As an example, the housing 11 is in the shape of a rectangular parallelepiped and includes four walls, which are connected end to end and together define the space inside the housing 11. Two opposing walls are large-area walls, and the other two are small-area walls. The outer surfaces of the large-area walls are larger than the outer surfaces of the small-area walls. One or two of the small-area walls in the housing 11 are first walls 13.

[0271] In this embodiment, the housing 11 has openings at both opposing ends. The electrode assembly 2 can be assembled into the housing 11 through either opening, which reduces the difficulty of assembling the battery cell 10 and improves the assembly quality of the battery cell 10. This structure of the housing 11 allows for a greater height (openings are formed at both ends of the housing 11 in the height direction), which helps increase the capacity of the battery cell 10.

[0272] In some embodiments, the pressure relief component 6 is made of steel.

[0273] The steel material can be carbon steel, alloy steel, stainless steel, etc.

[0274] It is understood that in the embodiment where the pressure relief component 6 and the first wall portion 13 are integrally formed, the material of the first wall portion 13 includes steel. If the first wall portion 13 is the end cap 12, the end cap 12 can be made of steel; if the first wall portion 13 is a wall portion in the housing 11, the housing 11 can be made of steel.

[0275] In this embodiment, steel has the characteristic of high strength, and the pressure relief component 6 made of steel has greater strength. Under the condition of a constant burst pressure of the battery cell 10, the pressure relief component 6 can be made thinner, thereby reducing the volume of the pressure relief component 6. In the embodiment where the pressure relief component 6 is integrally formed with the first wall portion 13, the first wall portion 13 is made of steel and can be made thinner. Under the condition of a constant volume of the outer shell 1, the volume of the outer shell 1 can be increased to provide more space for the electrode assembly 2, which is conducive to improving the volumetric energy density of the battery cell 10.

[0276] In some embodiments, the steel material is carbon steel or stainless steel.

[0277] Carbon steel can be low carbon steel, medium carbon steel or high carbon steel.

[0278] In some embodiments, the pressure relief component 6 is made of aluminum alloy.

[0279] It is understood that in the embodiment where the pressure relief component 6 and the first wall portion 13 are integrally formed, the material of the first wall portion 13 includes an aluminum alloy. If the first wall portion 13 is the end cap 12, the end cap 12 can be made of an aluminum alloy; if the first wall portion 13 is a wall portion in the housing 11, the housing 11 can be made of an aluminum alloy.

[0280] Aluminum alloy has the characteristics of light weight and good ductility, which makes it easier to machine the first groove 61 on the pressure relief component 6.

[0281] In some embodiments, the aluminum alloy includes the following components in mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other individual elements ≤ 0.03%.

[0282] This aluminum alloy belongs to the third series aluminum, has lower hardness and better forming ability, reduces the difficulty of processing the first groove 61, is conducive to improving the processing accuracy of the first groove 61, and improves the pressure relief consistency of the pressure relief component 6.

[0283] In some embodiments, the aluminum alloy includes the following components in mass percentage: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other individual element components ≤ 0.05%, and the total composition of other elements ≤ 0.15%.

[0284] This aluminum alloy belongs to the fifth series aluminum. The pressure relief component 6 made of this aluminum alloy has higher hardness, greater strength, and good anti-destruction ability. The embodiment of the present application provides a battery 100, including the battery cell 10 provided by any of the above embodiments.

[0285] An embodiment of the present application provides a battery 100 , comprising the battery cell 10 provided in any one of the above embodiments.

[0286] An embodiment of the present application provides an electrical device, comprising a battery cell 10 provided by any one of the above embodiments, and the battery cell 10 is used to provide electrical energy to the electrical device.

[0287] Referring to FIG3 , an embodiment of the present application further provides a battery cell 10, comprising a housing 1 and an electrode assembly 2. The electrode assembly 2 comprises a positive tab and a negative tab, and the electrode assembly 2 is housed within the housing 1. The housing 1 is rectangular and comprises a shell 11 and an end cap 12. The shell 11 has an opening at one end, and the end cap 12 seals the opening. The end cap 12 is provided with a positive electrode terminal and a negative electrode terminal. The positive electrode terminal is electrically connected to the positive tab via a current collecting member 4, and the negative electrode terminal is electrically connected to the negative tab via another current collecting member 4.

[0288] 8-12 , the wall portion of the housing 11 opposite the end cap 12 is the pressure relief component 6. The pressure relief component 6 is a rectangular wall portion. A first groove 61 is provided on the outer surface of the pressure relief component 6, and two second grooves 62 are provided on the inner surface of the pressure relief component 6. Along the width direction of the pressure relief component 6, the first groove 61 is located between the two second grooves 62, and the second grooves 62 are spaced apart from the first groove 61. The first groove 61 includes a plurality of groove segments 611. The minimum residual thickness of the groove segments 611 is less than the minimum residual thickness of the second grooves 62. The groove segments 611 are stepped grooves, forming two-stage grooves. Multiple slot segments 611 form an H-shaped structure. The first groove 61 includes a first slot segment 611a, a second slot segment 611b and a third slot segment 611c. The first slot segment 611a, the second slot segment 611b and the third slot segment 611c all extend along a straight line. The second slot segment 611b and the third slot segment 611c are arranged in parallel. The first slot segment 611a connects the second slot segment 611b and the third slot segment 611c. The second slot segment 611b and the third slot segment 611c are both perpendicular to the first slot segment 611a. The connection position between the first slot segment 611a and the second slot segment 611b is located at the midpoint of the second slot segment 611b, and the connection position between the first slot segment 611a and the third slot segment 611c is located at the midpoint of the third slot segment 611c. Along the thickness direction of the first wall portion 13, the second slot segment 611b and the third slot segment 611c extend from both ends of the projection of the second groove 62 along the extension direction. Among them, the first groove section 611a, the second groove section 611b, and the third groove section 611c jointly define two predetermined pressure relief areas 63, each predetermined pressure relief area 63 is arranged corresponding to a second groove 62, and the pressure relief component 6 is configured to be able to split along at least a portion of the first groove 61 when the battery cell 10 is depressurized, and the second groove 62 is configured to guide at least a portion of the predetermined pressure relief area 63 to flip over to open at least a portion of the predetermined pressure relief area 63.

[0289] The minimum width of the bottom surface 6111 of the groove section is W. The minimum residual thickness of the groove section 611 along the thickness direction of the first wall portion 13 is D1, 0.005 mm. 2 ≤W×D1≤0.12mm 2 , 0.05mm≤W≤0.5mm, 0.05mm≤D1≤0.6mm.

[0290] In such a battery cell 10, W×D1≥0.005 mm 2 , improves the fatigue strength of the area where the pressure relief component 6 is provided with the groove section 611, reduces the risk of the pressure relief component 6 prematurely cracking along the groove section 611 during normal use of the battery cell 10, and improves the service life of the battery cell 10. W×D1≤0.12mm 2, so that the pressure relief component 6 can be more timely cracked along the groove section 611 when the battery cell 10 is in thermal runaway, thereby improving the timeliness of the pressure relief of the battery cell 10 and reducing the risk of explosion of the battery cell 10. Therefore, 0.005mm 2 ≤W×D1≤0.12mm 2 , taking into account both the service life requirements of the battery cell 10 during normal use and the reliability requirements of the battery cell 10 in the event of thermal runaway. In addition, the pressure relief component 6 is provided with a second groove 62, which can guide at least a portion of the predetermined pressure relief area 63 to flip over, thereby opening at least a portion of the predetermined pressure relief area 63 for pressure relief. The second groove 62 assists the predetermined pressure relief area 63, making it easier to flip over, reducing the difficulty of flipping the predetermined pressure relief area 63. This allows the predetermined pressure relief area 63 to open more quickly during the process of the pressure relief component 6 splitting along the first groove 61, thereby increasing the opening rate of the predetermined pressure relief area 63.

[0291] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0292] The features and performance of the present application are further described in detail below with reference to the embodiments.

[0293] The battery cells 10 in each embodiment and comparative example were prepared and tested according to the following methods.

[0294] 1. Preparation of Battery Cell 10

[0295] 1. Preparation of positive electrode

[0296] The positive electrode active material LiNi 0.7 Co 0.1 Mn 0.1 O2, conductive agent Super P, and binder polyvinylidene fluoride (PVDF) are prepared into positive electrode slurry in N-methylpyrrolidone (NMP), wherein the solid content in the positive electrode slurry is 50wt%, and the solid content of LiNi 0.7 Co 0.1 Mn 0.1 The mass ratio of O2, Super P and PVDF is 8:1:1. The positive electrode slurry is coated on the upper and lower surfaces of the current collector aluminum foil and dried at 85°C and then cold pressed. Then, it is trimmed, cut and striped, and dried under vacuum conditions at 85°C for 4 hours to make the positive electrode sheet.

[0297] 2. Preparation of negative electrode sheet

[0298] Graphite, conductive agent Super P, thickener carboxymethyl cellulose (CMC), and adhesive styrene-butadiene rubber (SBR) were mixed evenly in deionized water to prepare a negative electrode slurry, wherein the solid content in the negative electrode slurry was 30wt%, and the mass ratio of graphite, silicon oxide, Super P, CMC, and adhesive styrene-butadiene rubber (SBR) in the solid components was 88:7:3:2. The negative electrode slurry was coated on the upper and lower surfaces of the current collector copper foil and dried at 85°C. Then, it was cold pressed, trimmed, cut into pieces, and slit, and then dried under vacuum conditions at 120°C for 12 hours to prepare a negative electrode sheet.

[0299] 3. Preparation of Electrolyte

[0300] In an argon atmosphere glove box (H2O <0.1ppm, O2 <0.1ppm), the fully dried electrolyte salt LiPF6 was dissolved in a mixed solvent (the mixed solvent included ethylene carbonate (EC) and diethyl carbonate (DEC), and ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a mass ratio of 50:50), and after mixing evenly, a liquid electrolyte with a concentration of 1 mol / L was obtained.

[0301] 4. Isolation

[0302] A 16 μm polyethylene film was used as a separator.

[0303] 5. Preparation of Battery Cell 10

[0304] The positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator placed in the middle of the positive and negative electrode sheets to isolate the positive and negative electrodes. The electrode assembly 2 is wound and placed in an aluminum shell 1. The prepared electrolyte is injected into the dried shell 1. The battery cell 10 is prepared by packaging, standing, forming, shaping, and capacity testing.

[0305] The battery cells 10 in each embodiment and comparative example are prepared using the above method. The battery cells 10 in each embodiment and comparative example are of the same chemical system. The difference between the battery cells 10 in each embodiment and comparative example lies in the different minimum width W of the groove bottom surface 6111 of the groove segment of the first groove 61 and the minimum residual thickness D1 of the groove segment 611. In each embodiment and comparative example, the outer shell 1 of the battery cell 10 is a rectangular parallelepiped structure, the shell 11 of the outer shell 1 is a structure with an opening formed at one end, the wall portion of the shell 11 opposite to the end cover 12 is the first wall portion 13, the first wall portion 13 is a rectangular wall portion, the shell 11 is made of aluminum alloy, the wall portion of the shell 11 opposite to the end cover 12 is the first wall portion 13, the first wall portion 13 serves as a pressure relief component 6, the first groove 61 is an H-shaped structure, and is a two-stage groove, the first groove 61 is arranged on the outer surface of the first wall portion 13, and the second groove 62 is arranged on the inner surface of the first wall portion 13, along the width direction of the first wall portion 13, the first groove 61 is located between the two second grooves 62. In each embodiment and comparative example, the groove segment 611 measured is the first groove segment 611a. When measuring the minimum width W of the groove bottom surface 6111 of the first groove segment 611a and the minimum residual thickness D1 of the first groove segment 611a, the first wall portion 13 is cut along a direction perpendicular to the first groove segment 611a, and W and D1 are measured on the cut surface.

[0306] 2. Performance parameter testing

[0307] 1. Method for measuring the number of cycle fatigue of battery cell 10

[0308] 1) Prepare a special test fixture. Specifically, the fixture includes three 10mm steel plates (first steel plate, second steel plate, and third steel plate). Each steel plate can completely cover the large surface of the battery cell 10 (the outer surface of the shell 11 perpendicular to the width direction of the first wall portion 13). The first steel plate and the third steel plate are located at both ends of the fixture and are fixed by bolts. The second steel plate is located between the first and third steel plates, and the second steel plate is constrained by a guide rail. The second steel plate can only move translationally along the thickness direction of the second steel plate.

[0309] 2) The battery cell 10 is installed between the first steel plate and the second steel plate, and a support structure is placed between the large surface of one side of the battery cell 10 and the first steel plate, and between the large surface of the other side and the second steel plate. The support structure can be an insulation pad or a water-cooling plate (consistent with the material / structure between two adjacent battery cells 10 in the actual battery 100). The support structure can be compressed to provide expansion space for the battery cell 10 during the charge and discharge cycle aging process; the large surface of the battery cell 10 is in contact with the support structure, the first steel plate is in contact with the corresponding support structure, the second steel plate is in contact with the corresponding support structure, and a pressure sensor is provided between the second steel plate and the third steel plate.

[0310] 3) Adjust the position of the second steel plate by adjusting the pre-tightening force of the bolts, observe the pressure sensor, make the initial extrusion force on the battery cell 10 2000N, and connect the positive electrode terminal and the positive electrode terminal of the battery cell 10 to the charging and discharging equipment.

[0311] 4) Place the battery cell 10 and the fixture in a constant temperature environment of 25±2°C, and start the test after the battery cell 10 reaches temperature equilibrium.

[0312] 5) The test steps are carried out in accordance with Section 6.4 "Standard Cycle Life" of GBT31484-2015 Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles, and the test cycle end condition is changed to "stop testing until damage occurs at the first groove 61 provided on the first wall portion 13".

[0313] Specifically, test according to the following steps:

[0314] a) Discharge to 2.8V with a current of 1I1(A);

[0315] b) Leave it for no less than 30 minutes;

[0316] c) Charge in accordance with the method 6.1.1.3 of GBT31484-2015 Cycle Life Requirements and Test Methods for Power Batteries for Electric Vehicles;

[0317] d) Leave it for no less than 30 minutes;

[0318] e) Discharge to 2.8V at a current of 1I1(A);

[0319] f) Repeat steps b) to e) until the first wall portion 13 where the first groove 61 is provided is damaged, and then the test is stopped.

[0320] That is, during the test, the area where the first groove 61 is provided on the first wall portion 13 of the battery cell 10 is continuously observed until the area breaks and leaks. The number of cycles is recorded as the cycle fatigue number of the battery cell 10. The greater the cycle fatigue number of the battery cell 10, the lower the probability of the battery cell 10 opening the valve and leaking liquid due to gas production during long-term use, and the longer the service life.

[0321] 2. Thermal runaway test method for battery cell 10

[0322] 1. Select the heating plate according to the size of the battery cell 10. The size of the heating plate should cover as much of the battery cell 10 as possible (coverage area ≥ 60%);

[0323] 2. Before testing, charge the battery cell 10 to 100% SOC and place the battery cell 10 in a constant temperature environment of 25±2°C;

[0324] 3. Sensor layout:

[0325] 1) Arrangement of temperature-sensing wires: A layer of Teflon is applied to the center of the two large surfaces of the battery cell 10, and a temperature-sensing wire is arranged above the Teflon, followed by another layer of Teflon.

[0326] 2) Layout of voltage sampling line: A layer of Teflon is applied to the positive electrode terminal, the positive electrode terminal and the housing 1 of the battery cell 10, a voltage sampling line is arranged above the Teflon, and another layer of Teflon is applied;

[0327] 3) Air pipe arrangement: Drill a hole in the first wall 13 of the battery cell 10 at the midpoint between the first groove 61 and the side surface of the housing 11 (the outer surface of the wall of the housing 11 adjacent to the first wall 13 along the length of the first wall 13). Insert the air pipe into the hole and seal it. Connect the air pipe to the air pressure sensor.

[0328] 4) Connect the temperature sensing wire, voltage sampling wire and air pressure sensor to the data acquisition instrument to collect and analyze data in real time. The acquisition frequency of the data acquisition instrument is ≤0.1S;

[0329] 4. Assembly fixture: The fixture is used to completely cover the large surface of the battery cell 10 (the outer surface of the housing 11 perpendicular to the width direction of the first wall 13). The clamping force is 3000N. The arrangement order of the fixture, heating plate and battery cell 10 is: fixture + heating plate + battery cell 10 + fixture.

[0330] 5. Test: Turn on the data acquisition instrument to collect temperature, voltage, and air pressure data, then turn on the heating plate at a power of 500W to heat the battery cell 10 until the battery cell 10 thermally runs away.

[0331] 6. Obtaining the pressure holding time of the battery cell 10: Determine the thermal runaway moment and the valve opening moment based on the temperature, voltage, and air pressure data collected by the data acquisition instrument, and obtain the pressure holding time of the battery cell 10 based on the formula: pressure holding time = valve opening moment - thermal runaway moment.

[0332] Thermal runaway criteria: a) The triggering object generates a voltage drop exceeding 25% of the initial voltage; b) The temperature at the detection point reaches the manufacturer's maximum operating temperature; c) The temperature rise rate dT / dt at the detection point is ≥ 1°C / s and persists for more than 3 seconds. Thermal runaway is determined to have occurred when a) and c) or b) and c) occur, and the moment of thermal runaway is determined.

[0333] Valve opening timing determination: When the air pressure drops by more than 25%, it can be determined that the valve is open (the first wall portion 13 is at least partially cracked along the first groove 61). The moment when the air pressure begins to drop is the valve opening timing.

[0334] 3. Test Results

[0335] The performance test results of the battery cells 10 in various embodiments and comparative examples are shown in Table 1, and are as follows:

[0336] Table 1

[0337] As shown in Table 1, it can be seen from the comparison between Examples 1 to 9 and Comparative Examples 3 to 4 that when W×D1≤0.12mm 2 When W×D1≥0.005mm, the battery cell 10 has a shorter holding time during thermal runaway, a lower bursting pressure, and a more timely pressure relief during thermal runaway. This can reduce the risk of explosion of the battery cell 10 and improve the reliability of the battery cell 10. 2 When the battery cell 10 has a large number of cycle fatigue times, the fatigue strength of the area where the first groove 61 is set on the first wall portion 13 is improved, the long-term reliability of the battery cell 10 during normal use is improved, and the service life of the battery cell 10 can be effectively increased.

[0338] From the comparison between Examples 3 to 5 and Examples 1 to 2, it can be seen that when W×D1≥0.01mm 2 When W×D1≤0.05mm, the cycle fatigue times of the battery cell 10 are greater, further improving the service life of the battery cell 10. 2 The holding time of the battery cell 10 during thermal runaway is shorter, and the pressure relief of the battery cell 10 during thermal runaway is more timely, which can further improve the reliability of the battery cell 10.

[0339] The above embodiments are intended only to illustrate the technical solutions of this application and are not intended to limit this application. Those skilled in the art will appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application are intended to be within the scope of protection of this application.

Claims

1. A battery cell, comprising: A housing, including a first wall portion; A pressure relief component disposed on the first wall portion, the pressure relief component being provided with a first groove, and the pressure relief component being configured to be able to crack along at least a part of the first groove when the battery cell relieves pressure; Among them, the first groove includes at least one groove segment, the minimum width of the groove bottom surface of the groove segment is W, and along the thickness direction of the first wall portion, the minimum remaining thickness of the groove segment is D1, satisfying: 0.005mm 2 ≤W×D1≤0.12mm 2 .

2. The battery cell according to claim 1, wherein, 0.01mm 2 ≤W×D1≤0.05mm 2 。 3. The battery cell according to claim 1 or 2, wherein 0.05 mm ≤ W ≤ 0.5 mm; optionally, 0.1 mm ≤ W ≤ 0.3 mm.

4. The battery cell according to any one of claims 1-3, wherein, 0.05 mm ≤ D1 ≤ 0.6 mm; optionally, 0.08 mm ≤ D1 ≤ 0.4 mm.

5. The battery cell according to any one of claims 1-4, wherein, The first groove defines at least one predetermined pressure relief area, and the pressure relief component is provided with a second groove, and the second groove is configured to guide at least a part of the predetermined pressure relief area to flip so as to open at least a part of the predetermined pressure relief area.

6. The battery cell according to claim 5, wherein The minimum remaining thickness of the second groove is D2, satisfying: D1 < D2.

7. The battery cell according to claim 6, wherein, Along the thickness direction of the first wall portion, the maximum groove depth of the groove segment is H1, and the maximum groove depth of the second groove is H2, satisfying: H2 < H1.

8. The battery cell according to any one of claims 5-7, wherein, The pressure relief component is provided with a plurality of the second grooves, the first groove defines a plurality of the predetermined pressure relief areas, and each of the predetermined pressure relief areas is correspondingly arranged with at least one of the second grooves.

9. The battery cell according to any one of claims 5-8, wherein, Along the thickness direction of the first wall portion, the projection of the second groove does not overlap with the projection of the first groove.

10. The battery cell according to claim 9, wherein, Along the width direction of the second groove, the second groove and the first groove are arranged at intervals.

11. The battery cell according to any one of claims 5-10, wherein, Along the thickness direction of the first wall portion, the two ends of the projection of the second groove along the extending direction respectively extend out of the two ends of the projection of the first groove.

12. The battery cell according to any one of claims 5-11, wherein, Along the thickness direction of the first wall portion, the pressure relief component has a first surface and a second surface which are oppositely arranged, the first groove is arranged on the first surface, and the second groove is arranged on the second surface.

13. The battery cell according to claim 12, wherein, The first surface is the surface of the pressure relief component facing the outside of the housing, and the second surface is the surface of the pressure relief component facing the inside of the housing.

14. The battery cell according to any one of claims 5-13, wherein, Along the thickness direction of the first wall portion, the pressure relief component has a second surface facing the inside of the housing, and the second groove is arranged on the second surface.

15. The battery cell according to any one of claims 5-14, wherein, The first wall portion is a rectangular wall portion, and the first groove and the second groove are arranged along the width direction of the first wall portion.

16. The battery cell according to any one of claims 5-15, wherein, The second groove extends along a straight track.

17. The battery cell according to any one of claims 1-16, wherein, Along the thickness direction of the first wall portion, the pressure relief component has a first surface and a second surface which are oppositely arranged, the groove segment includes multiple levels of grooves sequentially arranged from the first surface towards the direction close to the second surface, and in two adjacent levels of grooves, the level of groove farther from the first surface is arranged on the groove bottom surface of the level of groove closer to the first surface; Wherein, the level of groove farthest from the first surface in the multiple levels of grooves is the first-level groove, the minimum remaining thickness of the first-level groove is the minimum remaining thickness of the groove segment, and the groove bottom surface of the first-level groove is the groove bottom surface of the groove segment.

18. The battery cell according to any one of claims 1-17, wherein, The first groove includes a plurality of the groove segments, the plurality of the groove segments include a first groove segment and a second groove segment, the first groove segment is connected to the second groove segment, and the first groove segment and the second groove segment jointly define at least one predetermined pressure relief area.

19. The battery cell according to any one of claims 1-17, wherein, The first groove includes a plurality of groove segments, the plurality of groove segments including a first groove segment, a second groove segment, and a third groove segment. The second groove segment and the third groove segment are oppositely arranged, the first groove segment connects the second groove segment and the third groove segment, and the first groove segment, the second groove segment, and the third groove segment together define at least one predetermined pressure relief area.

20. The battery cell according to claim 19, wherein, The connection position of the second groove segment and the first groove segment deviates from both ends of the second groove segment, and the connection position of the third groove segment and the first groove segment deviates from both ends of the third groove segment, so that the predetermined pressure relief areas are formed on both sides of the first groove segment.

21. The battery cell according to claim 19 or 20, wherein, The first groove segment extends along a straight or arc trajectory; and / or, the second groove segment extends along a straight or arc trajectory; and / or, the third groove segment extends along a straight or arc trajectory.

22. The battery cell according to any one of claims 1-17, wherein, The first groove extends along an arc trajectory.

23. The battery cell according to any one of claims 1-22, wherein, The pressure relief component is integrally formed with the first wall portion; or, the pressure relief component is separately provided from the first wall portion, and the pressure relief component is installed on the first wall portion.

24. The battery cell according to any one of claims 1-23, wherein, The first groove is formed by stamping on the pressure relief component.

25. The battery cell according to any one of claims 1-24, wherein, The housing includes: A housing body, with an opening formed at at least one end; An end cover, corresponding to the opening one by one, and the end cover closes the opening; Wherein, at least one of the end covers is the first wall portion.

26. The battery cell according to any one of claims 1-25, wherein, The housing includes: A housing body, with an opening formed at at least one end; An end cover, corresponding to the opening one by one, and the end cover closes the opening; Wherein, at least one wall portion of the housing body is the first wall portion.

27. The battery cell according to claim 26, wherein, The housing body has the opening formed only at one end, and the wall portion of the housing body opposite to the end cover is the first wall portion.

28. The battery cell according to claim 26, wherein, The openings are formed at both opposite ends of the housing body, and at least one wall portion of the housing body is the first wall portion.

29. The battery cell according to any one of claims 1-28, wherein, The material of the pressure relief component includes steel material.

30. The battery cell according to claim 29, wherein, The steel material is carbon steel or stainless steel.

31. The battery cell according to any one of claims 1-28, wherein, The material of the pressure relief component includes aluminum alloy.

32. The battery cell according to claim 31, wherein, The aluminum alloy includes the following components by mass percentage: aluminum ≥ 99.6%, copper ≤ 0.05%, iron ≤ 0.35%, magnesium ≤ 0.03%, manganese ≤ 0.03%, silicon ≤ 0.25%, titanium ≤ 0.03%, vanadium ≤ 0.05%, zinc ≤ 0.05%, and other single elements ≤ 0.03%.

33. The battery cell according to claim 31, wherein, The aluminum alloy includes the following components by mass percentage: aluminum ≥ 96.7%, 0.05% ≤ copper ≤ 0.2%, iron ≤ 0.7%, manganese ≤ 1.5%, silicon ≤ 0.6%, zinc ≤ 0.1%, other single element components ≤ 0.05%, and other element total components ≤ 0.15%.

34. A battery, including a battery cell as described in any one of claims 1 - 33.

35. An electrical device, including a battery cell as described in any one of claims 1 - 33, and the battery cell is used to provide electrical energy for the electrical device.

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