Battery cell, battery, and electric device

Abstract

Embodiments of the present application provide a battery cell, a battery, and an electric device. The battery cell comprises a casing and an electrode assembly. The casing comprises a first wall part. The first wall part is provided with N pressure relief mechanisms arranged in a first direction. The electrode assembly is accommodated in the casing. The electrode assembly comprises a main body part and a tab. The main body part comprises a plurality of sub-regions. In the first direction, at least one end of the main body part is provided with the tab, the plurality of sub-regions are continuously arranged, the length of the main body part is L, the length of each sub-region is L1, L=L1×N, L≥400 mm, and N≥2. In the thickness direction of the first wall part, the projection of each pressure relief mechanism is correspondingly located in one sub-region. Each pressure relief mechanism can discharge a discharge medium generated by thermal runaway of the corresponding sub-region, and the discharge medium generated by thermal runaway of each sub-region can be quickly discharged through the corresponding pressure relief mechanism, so that the pressure relief timeliness of the battery cell can be effectively improved, thereby improving the reliability of the battery cell.

Description

Battery cells, batteries and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application (2023111199944) entitled “Battery Cell, Battery and Electrical Equipment” filed on September 1, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] 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

[0004] Batteries are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes and power tools, etc.

[0005] In battery technology, pressure relief mechanisms can be installed in battery cells to relieve pressure in the event of thermal runaway. However, typical battery cells still experience delayed pressure relief, resulting in poor reliability. Therefore, improving battery cell reliability is a pressing technical challenge in battery technology.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can effectively improve the reliability of the battery cell.

[0008] In a first aspect, an embodiment of the present application provides a battery cell comprising a shell and an electrode assembly; the shell comprises a first wall portion, and the first wall portion is provided with N pressure relief mechanisms arranged along a first direction; the electrode assembly is accommodated in the shell, and the electrode assembly comprises a main body portion and a tab, and at least one end of the main body portion is provided with a tab, and the main body portion comprises a plurality of sub-regions, and the plurality of sub-regions are continuously arranged along the first direction, the length of the main body portion is L, and the length of the sub-region is L1, L=L1×N, L≥400mm, and N≥2; wherein, along the thickness direction of the first wall portion, the projection of each pressure relief mechanism is correspondingly located within a sub-region, and the thickness direction of the first wall portion intersects with the first direction.

[0009] In the above technical solution, the projection of each pressure relief mechanism along the thickness direction of the first wall portion is located correspondingly in a sub-area, so that each sub-area can correspond to a pressure relief mechanism on the outer shell, and each pressure relief mechanism can discharge the emission medium generated by thermal runaway of a corresponding sub-area. If thermal runaway occurs in any sub-area, the emission medium generated by the thermal runaway can be quickly discharged through the corresponding pressure relief mechanism, which can effectively improve the timeliness of pressure relief of the battery cell, and thus improve the reliability of the battery cell.

[0010] In some embodiments, the first wall supports the main body along the direction of gravity. This allows emissions from the housing to be discharged from the bottom of the housing. Because the first wall supports the main body and is pressed against it, the area within the housing near the first wall is more susceptible to blockage and suffocation, hindering the discharge of the discharged medium. However, the presence of multiple pressure relief mechanisms on the first wall further facilitates the discharge of the discharged medium near the first wall, improving the reliability of the battery cells.

[0011] In some embodiments, the housing further comprises a second wall portion, the first wall portion and the second wall portion being arranged opposite each other along the thickness direction of the first wall portion, a channel gap being formed between the second wall portion and the main body portion, and the channel gap being configured to connect the spaces within the housing located at both ends of the main body portion along the first direction. The channel gap can connect the spaces within the housing located at both ends of the main body portion along the first direction. When thermal runaway occurs in a sub-region located at one end of the main body portion, the exhaust medium accumulated near the one end of the main body portion can be discharged through the pressure relief mechanism corresponding to the sub-region, or can flow to the other end of the main body portion through the channel gap and be discharged through the pressure relief mechanism corresponding to the sub-region at the other end of the main body portion, thereby enabling the exhaust medium within the battery cell to be quickly discharged, thereby improving the timeliness of the pressure relief of the battery cell.

[0012] In some embodiments, the housing further includes a third wall portion and a fourth wall portion, the third wall portion and the fourth wall portion being arranged opposite each other along the second direction, the first wall portion connecting the third wall portion and the fourth wall portion, and a plane formed by the intersection of the thickness direction of the first wall portion and the first direction intersecting the second direction; wherein the thickness of the third wall portion and the thickness of the fourth wall portion are both less than the thickness of the first wall portion. This increases the thickness of the first wall portion, improves the deformation resistance of the first wall portion, reduces the risk of excessive deformation of the first wall portion due to battery cell expansion, and further reduces the impact of deformation of the first wall portion on the pressure relief mechanism, reduces the risk of premature activation of the pressure relief mechanism, and increases the service life of the pressure relief mechanism.

[0013] In some embodiments, the sum of the predetermined pressure relief areas of the N pressure relief mechanisms is S1. Along the thickness direction of the first wall, the first wall has a first outer surface facing away from the main body. The area of ​​the first outer surface is S2, and 0.05 ≤ S1 / S2 ≤ 0.55. S1 / S2 ≥ 0.05 increases the total pressure relief area of ​​the N pressure relief mechanisms, facilitating an increased pressure relief rate and timely pressure relief of the battery cells. S1 / S2 ≤ 0.55 also enhances the strength of the first wall.

[0014] In some embodiments, 0.15≤S1 / S2≤0.35.

[0015] In some embodiments, the predetermined pressure relief areas of the N pressure relief mechanisms are equal, so that the pressure relief capabilities of all the pressure relief mechanisms on the first wall portion are substantially consistent, and the difficulty of forming each pressure relief mechanism can be reduced.

[0016] In some embodiments, the housing includes a first half and a second half. Along a first direction, the portion from the mid-section of the housing to one end of the housing constitutes the first half, and the portion from the mid-section to the other end of the housing constitutes the second half. Both the first half and the second half are provided with pressure relief mechanisms, and the first direction is perpendicular to the mid-section. In the event of thermal runaway of a battery cell, pressure relief can be provided through the pressure relief mechanisms in the first and second half regions. This allows exhaust media within the housing located in the first half region to be discharged more quickly through the pressure relief mechanisms in the first half region, while exhaust media within the housing located in the second half region can be discharged more quickly through the pressure relief mechanisms in the second half region, thereby improving the timeliness of pressure relief for the battery cell.

[0017] In some embodiments, the first wall is provided with only two pressure relief mechanisms, one located in the first half and the other in the second half. This reduces the number of pressure relief mechanisms on the first wall, enabling rapid pressure relief of the battery cells while reducing the manufacturing cost of the battery cells, resulting in better economic efficiency.

[0018] In some embodiments, the pressure relief mechanism is provided with a notched groove. Along the first direction, the length of the housing is L2, and the minimum distance between the notched grooves of two adjacent pressure relief mechanisms is L3, where L2>L, and L3 / L2≥1 / 6. This ensures that the minimum distance between the notched grooves of two adjacent pressure relief mechanisms is not too small, allowing each pressure relief mechanism to cover a larger area of ​​the main body, fully utilizing each pressure relief mechanism and improving the timely pressure relief of the battery cell.

[0019] In some embodiments, L3 / L2≥1 / 4.

[0020] In some embodiments, L2 ≥ 500 mm; and / or L3 ≥ 300 mm. L2 ≥ 500 mm indicates that the housing is relatively large in the first direction, meeting the large capacity requirements of the battery cell. L3 ≥ 300 mm ensures that the minimum distance between two adjacent pressure relief mechanisms is not too small, allowing each pressure relief mechanism to cover a larger area of ​​the main body. Discharge medium from the larger area of ​​the main body can be discharged through the corresponding pressure relief mechanism, fully utilizing each pressure relief mechanism and improving the timely pressure relief of the battery cell.

[0021] In some embodiments, the length of the housing along the first direction is L2. The pressure relief mechanisms are provided with scored grooves. The sum of the maximum spans of the scored grooves of the N pressure relief mechanisms along the first direction is D1, and 0.2 ≤ D1 / L2 ≤ 0.6. D1 / L2 ≥ 0.2 increases the sum of the maximum spans of the scored grooves of the multiple pressure relief mechanisms on the first wall along the first direction, thereby increasing the total pressure relief area of ​​the multiple pressure relief mechanisms on the first wall and facilitating an improved pressure relief rate for the battery cells. D1 / L2 ≤ 0.6 also limits the sum of the maximum spans of the scored grooves of the multiple pressure relief mechanisms on the first wall along the first direction to a minimum, thereby improving the strength of the first wall.

[0022] In some embodiments, the pressure relief mechanism is provided with a scored groove, forming a weak portion in the area where the scored groove is provided. The weak portion is configured to rupture to release pressure within the battery cell. The scored groove forms a weak portion in the corresponding area of ​​the pressure relief mechanism, which is a simple method for forming the weak portion. The weak portion is a more vulnerable area in the pressure relief mechanism and is more likely to be destroyed in the event of thermal runaway of the battery cell, thereby relieving pressure in a timely manner.

[0023] In some embodiments, along the thickness direction of the first wall, the notch of the notch faces the main body, so that the weak portion is not easily torn when the first wall is deformed by the expansion of the battery cell, thereby improving the long-term reliability of the pressure relief mechanism.

[0024] In some embodiments, the pressure relief mechanism includes a pressure relief zone, which is configured to open when the weak portion ruptures. During pressure relief, the pressure relief zone can open with the weak portion as the boundary, thereby increasing the pressure relief area of ​​the pressure relief mechanism.

[0025] In some embodiments, the scored groove is a groove extending along a closed trajectory and is disposed around the pressure relief area. During the pressure relief process, after the pressure relief mechanism ruptures along the scored groove, the pressure relief area can be separated from the first wall, thereby increasing the pressure relief area and improving the pressure relief rate of the battery cell.

[0026] In some embodiments, the pressure relief mechanism is integrally formed with the first wall portion, thereby increasing the reliability of the pressure relief mechanism, eliminating the need for a connection process between the pressure relief mechanism and the first wall portion, and reducing the production cost of the battery cell.

[0027] In some embodiments, the pressure relief mechanism is separately provided from the first wall portion, the first wall portion is provided with a pressure relief hole, and the pressure relief mechanism is mounted on the first wall portion and covers the pressure relief hole. The pressure relief mechanism is a component independent of the housing, and the pressure relief mechanism and the housing can be manufactured and assembled separately, which reduces production difficulty and improves efficiency.

[0028] In some embodiments, the first wall portion is provided with a first groove, which includes groove side surfaces and a first groove bottom surface. The groove side surfaces surround the first groove bottom surface, the pressure relief hole is provided in the first groove bottom surface, and the pressure relief mechanism is provided within the first groove and abuts against the first groove bottom surface. A gap is formed between the groove side surfaces and the pressure relief mechanism along at least a portion of the circumference of the first groove. When the first wall portion deforms due to expansion of the battery cell, the gap between the pressure relief mechanism and the groove side surfaces provides a buffer space for the pressure relief mechanism, reducing the risk of deformation caused by compression of the pressure relief mechanism by the groove side surfaces. This, in turn, reduces the risk of premature opening of the pressure relief mechanism during normal use of the battery cell and increases the service life of the pressure relief mechanism.

[0029] In some embodiments, the groove side includes a first region that forms a gap with the pressure relief mechanism. Along the circumference of the first groove, the length of the first region is L4, and the circumference of the groove side is L5, satisfying the following relationship: 0.2 ≤ L4 / L5 ≤ 1. This creates a gap between the longer circumferential portion of the groove side and the pressure relief mechanism, reducing the extent to which the groove side squeezes the pressure relief mechanism when the first wall portion deforms, further reducing the risk of premature deployment of the pressure relief mechanism during normal use of the battery cell.

[0030] In some embodiments, a gap is formed between the groove side surface and the pressure relief mechanism along the entire circumference of the first groove. This creates a gap between the groove side surface and the pressure relief mechanism along the entire circumference. This gap is an annular structure surrounding the pressure relief mechanism, further reducing the squeezing effect of the groove side surface on the pressure relief mechanism when the first wall portion deforms, further reducing the risk of premature opening of the pressure relief mechanism during normal use of the battery cell.

[0031] In some embodiments, the pressure relief mechanism is welded to the bottom wall of the first groove to form a first weld mark, thereby fixing the pressure relief mechanism to the first wall and improving the connection strength between the pressure relief mechanism and the first wall.

[0032] In some embodiments, the projection of the first weld mark along the thickness direction of the first wall portion is entirely located on the pressure relief mechanism. This allows the pressure relief mechanism to be welded to the bottom wall of the first groove via penetration welding. This simple welding method allows the first weld mark formed after welding to pass through the pressure relief mechanism and embed into the bottom wall of the first groove, thereby enhancing the connection strength between the pressure relief mechanism and the first wall portion. Furthermore, because the projection of the first weld mark along the thickness direction of the first wall portion is located on the pressure relief mechanism, the first weld mark does not protrude beyond the edge of the pressure relief mechanism and is not located within the gap between the pressure relief mechanism and the side surface of the groove. This reduces the risk of the side surface of the groove squeezing the pressure relief mechanism through the first weld mark when the first wall portion deforms.

[0033] In some embodiments, along the thickness direction of the first wall portion, the pressure relief mechanism is located on the side of the pressure relief hole away from the main body portion. In this way, the pressure relief mechanism can be installed on the outside of the first wall portion, making the pressure relief mechanism more convenient to install.

[0034] In some embodiments, the battery cell further includes a protective member located along the thickness direction of the first wall portion on a side of the pressure relief mechanism facing away from the main body, and covering the first groove. The protective member can protect the pressure relief mechanism and reduce the risk of foreign matter (impurities, electrolyte) entering the first groove and corroding the pressure relief mechanism.

[0035] In some embodiments, the first wall portion has a first outer surface facing away from the main body portion along its thickness direction. The first outer surface is provided with a second groove, the first groove being disposed at the bottom of the second groove, and the protective member being at least partially accommodated in the second groove. This can reduce the height of the protective member protruding from the first outer surface of the first wall portion, thereby reducing the space occupied by the protective member outside the housing.

[0036] In some embodiments, the pressure relief mechanism is located on the side of the pressure relief hole facing the main body along the thickness direction of the first wall. In this way, the pressure relief mechanism can be installed on the inner side of the first wall, and the first wall can protect the pressure relief mechanism and reduce the risk of damage to the first wall by external components.

[0037] In some embodiments, the battery cell further includes a protective member located along the thickness direction of the first wall portion on a side of the pressure relief hole facing away from the main body, and covering the pressure relief hole. The protective member can protect the pressure relief mechanism and reduce the risk of foreign matter (impurities, electrolyte) entering the pressure relief hole and corroding the pressure relief mechanism.

[0038] In some embodiments, the housing includes a shell and an end cap; the shell has an opening formed at at least one end along a first direction, and the shell includes a first wall portion; the end cap corresponds to the opening and closes the opening. When assembling the battery cell, the electrode assembly can be first installed in the shell, and then the shell opening can be closed with the end cap, making assembly of the battery cell convenient and quick.

[0039] In some embodiments, the housing has openings at both ends thereof along the first direction. When assembling the battery cells, the electrode assembly can enter the housing from either end, which can effectively improve the assembly efficiency of the battery cells.

[0040] In some embodiments, the housing is an integrally formed structure, which can improve the strength of the housing, improve the housing's ability to resist damage, and increase the service life of the housing.

[0041] In some embodiments, the housing is formed by bending a sheet material, with the first and second ends of the sheet material connected to each other along the circumference of the opening. Forming the housing requires only bending the sheet material and connecting the first and second ends. This simplifies the forming process and effectively reduces the difficulty of forming the housing.

[0042] In some embodiments, the two ends are welded to form a second weld mark, so that the two ends have good connection strength and are more firmly connected.

[0043] In some embodiments, the housing further includes a second wall portion, the first wall portion and the second wall portion being disposed opposite each other along the thickness direction of the first wall portion; wherein the second weld mark portion is located on the second wall portion. This allows the second weld mark portion and the pressure relief mechanism to be located on two opposing walls of the housing, thereby reducing the impact of the two ends of the plate on the pressure relief mechanism during welding and improving the reliability of the pressure relief mechanism.

[0044] In some embodiments, the outer shell is rectangular, with the first direction parallel to the length of the outer shell. The outer shell has a simple structure and is easy to form. When the battery cells are incorporated into a battery, the rectangular outer shell of the battery cells can reduce the installation gap between the battery cells, thereby improving the volumetric energy density of the battery.

[0045] 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.

[0046] 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

[0047] 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.

[0048] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0049] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0050] FIG3 is an axonometric view of a battery cell provided in some embodiments of the present application;

[0051] FIG4 is an exploded view of the battery cell shown in FIG3 ;

[0052] FIG5 is a cross-sectional view of a battery cell provided in some embodiments of the present application;

[0053] FIG6 is a cross-sectional view of the housing shown in FIG5 taken along the YZ plane;

[0054] FIG7 is a view of the battery cell shown in FIG5 taken along the direction of arrow A;

[0055] FIG8 is a partial enlarged view of the housing B shown in FIG6 ;

[0056] FIG9 is a partial view of a first wall portion provided in some embodiments of the present application;

[0057] FIG10 is a partial view of a first wall portion provided in some other embodiments of the present application;

[0058] FIG11 is a partial view of a first wall portion provided in some further embodiments of the present application;

[0059] FIG12 is an exploded view of a battery cell provided in some other embodiments of the present application;

[0060] FIG13 is a cross-sectional view of the battery cell shown in FIG12 ;

[0061] FIG14 is a partial enlarged view of the battery cell C shown in FIG13;

[0062] FIG15 is a cross-sectional view of the first wall portion shown in FIG14;

[0063] FIG16 is an assembly diagram of a pressure relief mechanism and a first wall portion provided in some embodiments of the present application;

[0064] FIG17 is a schematic structural diagram of the first wall portion shown in FIG16 ;

[0065] FIG18 is an assembly diagram of a pressure relief mechanism and a first wall portion provided in some other embodiments of the present application;

[0066] FIG19 is a partial view of a battery cell provided in some other embodiments of the present application;

[0067] FIG20 is a partial view of a battery cell provided in some other embodiments of the present application;

[0068] FIG21 is an exploded view of a housing provided in some embodiments of the present application;

[0069] FIG22 is an exploded view of a housing provided in some other embodiments of the present application;

[0070] FIG23 is a schematic structural diagram of the housing shown in FIG21;

[0071] FIG24 is a schematic structural diagram of a housing provided in some other embodiments of the present application;

[0072] FIG25 is a cross-sectional view of the housing shown in FIG24 taken along the YZ plane;

[0073] FIG26 is an expanded view of the housing shown in FIG25 .

[0074] Icons: 1-shell; 11-shell; 111-first wall; 1111-pressure relief hole; 1112-first groove; 1112a-groove side; 1112b-first groove bottom; 1112c-groove bottom wall; 1112d-first area; 1112e-first side; 1112f-second side; 1113-first outer surface; 1114-second groove; 1115-first surface; 1116-protrusion; 112-second wall; 1121-first end; 1121a-first end surface; 1122-second end; 1122a-second end surface; 113-third wall; 114-fourth wall; 115-second weld print; 12-end cover; 13-channel gap; 14-first space; 15-second space; 16-first half area; 17- Second half area; 2-electrode assembly; 21-main body; 211-sub-area; 22-ear; 3-pressure relief mechanism; 31-notched groove; 311-first arc segment; 312-first straight line segment; 313-second straight line segment; 314-third straight line segment; 315-fourth straight line segment; 316-fifth straight line segment; 317-first connecting line; 318-second connecting line; 32-weak part; 33-pressure relief area; 34-outer peripheral surface; 4-electrode terminal; 5-gap; 6-first weld stamp; 7-protective part; 10-battery cell; 20-housing; 201-first part; 202-second part; 100-battery; 200-controller; 300-motor; 1000-vehicle; W-mid-section; X-first direction; Y-second direction; Z-thickness direction of the first wall. DETAILED DESCRIPTION

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] The term "plurality" used in this application refers to two or more (including two).

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.).

[0087] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0088] 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.

[0089] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0090] As an example, the negative electrode current collector can be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium can be used. The metal foam can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical and mechanical stability.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0102] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0103] 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.

[0104] 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.

[0105] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0106] 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.

[0107] In some embodiments, the electrode assembly is a laminate structure.

[0108] 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.

[0109] 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.

[0110] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0111] 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.

[0112] 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.

[0113] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0122] 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, the reliability of battery cells must also be considered.

[0123] In battery technology, pressure relief mechanisms can be installed in battery cells to improve their reliability. These mechanisms have a significant impact on battery reliability. For example, short circuits and overcharging can cause thermal runaway within the battery cell, leading to a sudden increase in pressure or temperature. In these situations, the pressure relief mechanism releases internal pressure and temperature, reducing the likelihood of explosion or fire.

[0124] In a typical battery cell, the battery cell includes a housing and an electrode assembly. The electrode assembly is housed within the housing. The electrode assembly includes a main body and tabs, with tabs provided at one or both ends of the main body along a predetermined direction. The housing is provided with only one pressure relief mechanism, located at one end of the housing along the predetermined direction. In the event of thermal runaway of the battery cell, the exhaust medium within the housing is discharged through this pressure relief mechanism to relieve pressure within the battery cell. In such a battery cell, if the main body is longer than or equal to 400 mm, in the event of thermal runaway, the exhaust medium generated in the area of ​​the main body near the pressure relief mechanism can flow to the pressure relief mechanism, but the exhaust medium generated in the area of ​​the main body far from the pressure relief mechanism is unlikely to flow to the pressure relief mechanism, resulting in delayed pressure relief and poor reliability of the battery cell.

[0125] In view of this, an embodiment of the present application provides a battery cell, in which N pressure relief mechanisms are arranged along a first direction on the first wall portion of the shell, L ≥ 400 mm, N ≥ 2, and the main part of the electrode assembly is divided into N sub-regions arranged continuously along the first direction, and the length of each sub-region along the first direction is equal. Along the thickness direction of the first wall portion, the projection of each pressure relief mechanism is located in a corresponding sub-region.

[0126] In such a battery cell, when the length of the main body is greater than or equal to 400 mm, each sub-region can correspond to a pressure relief mechanism on the outer shell. Each pressure relief mechanism can discharge the emission medium generated by thermal runaway of a corresponding sub-region. If thermal runaway occurs in any sub-region, the emission medium generated by the thermal runaway can be quickly discharged through the corresponding pressure relief mechanism, which can effectively improve the timeliness of pressure relief of the battery cell and thus improve the reliability of the battery cell.

[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] In some embodiments, the battery 100 may further include a busbar component, through which the multiple battery cells 10 can be electrically connected to each other, thereby enabling series connection, parallel connection, or hybrid connection of the multiple battery cells 10. The busbar component may be a metal conductor, such as copper, iron, aluminum, stainless steel, or aluminum alloy.

[0137] 3 and 4 , FIG3 is an isometric view of a battery cell 10 provided in some embodiments of the present application; FIG4 is an exploded view of the battery cell 10 shown in FIG3 . The battery cell 10 may include a housing 1 , an electrode assembly 2 , and a pressure relief mechanism 3 .

[0138] The housing 1 is a component for accommodating the electrode assembly 2 and electrolyte, etc. As an example, the housing 1 may include a shell 11 and an end cap 12 .

[0139] The housing 11 may be a hollow structure with an opening at one end, or may be a hollow structure with openings at opposite ends. The housing 11 may have various shapes, such as a cylindrical or prismatic shape. The housing 11 may be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc.

[0140] 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 storage space for accommodating the electrode assembly 2, electrolyte and other components. 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.

[0141] 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.

[0142] The pressure relief mechanism 3 is a component that releases pressure from the battery cell 10. When the internal pressure of the battery cell 10 reaches a threshold, the pressure relief mechanism 3 discharges the exhaust medium from the battery cell 10 to achieve the purpose of pressure relief. Exhaust media include, but are not limited to, electrolyte, dissolved or split positive and negative electrode sheets, separator fragments, reaction gases, flames, etc. The pressure relief mechanism 3 can be located in the housing 11 or the end cap 12.

[0143] In some embodiments, the battery cell 10 may further include an electrode terminal 4, which is disposed on the outer casing 1 and is used to electrically connect to the tab 22 of the electrode assembly 2 to input or output electrical energy from the battery cell 10. The electrode terminal 4 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 4 and the tab 22 may be directly connected, for example, by direct welding. The electrode terminal 4 and the tab 22 may also be indirectly connected, for example, by indirectly connecting the electrode terminal 4 and the tab 22 via a current collecting member.

[0144] As an example, as shown in Figure 4, the shell 11 is a hollow structure with openings formed at opposite ends. End covers 12 are provided at the opposite ends of the shell 11. Electrode terminals 4 are provided on the end covers 12 at both ends of the shell 11. Pole ears 22 are formed at the opposite ends of the electrode assembly 2. The pole ear 22 at one end of the electrode assembly 2 is a positive pole ear, and the pole ear 22 at the other end of the electrode assembly 2 is a negative pole ear. The electrode terminal 4 on one end cover 12 is electrically connected to the positive pole ear, and the electrode terminal 4 on the other end cover 12 is electrically connected to the negative pole ear.

[0145] Please refer to Figure 5, which is a cross-sectional view of a battery cell 10 provided in some embodiments of the present application. Embodiments of the present application provide a battery cell 10, comprising a housing 1 and an electrode assembly 2. The housing 1 includes a first wall 111, which is provided with N pressure relief mechanisms 3 arranged along a first direction X. The electrode assembly 2 is housed within the housing 1 and includes a main body 21 and a tab 22. The tab 22 is provided at at least one end of the main body 21. The main body 21 includes a plurality of sub-regions 211, which are arranged continuously along the first direction X. The main body 21 has a length L, and the sub-regions 211 have a length L1, where L = L1 × N, L ≥ 400 mm, and N ≥ 2. Furthermore, along the thickness direction Z of the first wall, the projection of each pressure relief mechanism 3 is located within a corresponding sub-region 211, and the thickness direction Z of the first wall intersects the first direction X.

[0146] The housing 1 may be cylindrical, prismatic, or the like. The prism may be a triangular prism, a quadrangular prism, a pentagonal prism, a hexagonal prism, or the like. The quadrangular prism may include a rectangular parallelepiped, a cube, or the like. In embodiments where the housing 1 is cylindrical, the first direction X may be parallel to the axial direction of the housing 1; in embodiments where the housing 1 is rectangular parallelepiped, the first direction X may be parallel to the longitudinal direction of the housing 1.

[0147] The first wall portion 111 may be the end cap 12 of the housing 1. It is understood that the end cap 12 is provided with a pressure relief mechanism 3. The first wall portion 111 may also be at least one wall portion of the shell 11 in the housing 1. It is understood that the housing 1 is provided with a pressure relief mechanism 3. There may be two, three, four, five, six, or more pressure relief mechanisms 3 on the first wall portion 111. Therefore, N may be 2, 3, 4, 5, 6, etc.

[0148] The pressure relief mechanism 3 is a component that releases pressure from the battery cell 10. When the internal pressure of the battery cell 10 reaches a threshold, the pressure relief mechanism 3 discharges the exhaust medium from the battery cell 10 to achieve the purpose of pressure relief. Exhaust media include, but are not limited to, electrolyte, dissolved or split positive and negative electrode sheets, separator fragments, reaction gases, flames, etc. The pressure relief mechanism 3 and the first wall portion 111 can be integrally formed or separate.

[0149] The main body 21 has two opposite ends along a preset direction. The tab 22 may be provided at one end of the main body 21, or at both opposite ends of the main body 21. The preset direction may be parallel to the first direction X, or may intersect with it. For example, the preset direction is perpendicular to the first direction X. As an example, the preset direction is parallel to the first direction X, that is, the tab 22 is provided at least at one end of the main body 21 along the first direction X. In the embodiment shown in Figure 5, the tabs 22 are provided at both ends of the main body 21 in the first direction X. The tab 22 at one end is a positive tab, and the tab 22 at the other end is a negative tab. Electrode terminals 4 are provided at both ends of the shell 1. The electrode terminal 4 at one end of the shell 1 is electrically connected to the tab 22 at one end of the main body 21, and the electrode terminal 4 at the other end of the shell 1 is electrically connected to the tab 22 at the other end of the main body 21.

[0150] The electrode assembly 2 may include a positive electrode sheet, a negative electrode sheet, and a separator. The electrode assembly 2 may be a wound structure formed by winding the positive electrode sheet, separator, and negative electrode sheet, or a laminated structure formed by stacking the positive electrode sheet, separator, and negative electrode sheet. The main body 21 may be the portion of the electrode assembly 2 corresponding to the area of ​​the electrode sheet coated with the active material layer. The positive electrode tab may be the portion of the positive electrode sheet not coated with the positive electrode active material layer, and the negative electrode tab may be the portion of the negative electrode sheet not coated with the negative electrode active material layer.

[0151] L = L1 × N means that along the first direction X, the main body 21 is evenly divided into a plurality of sub-regions 211. The number of sub-regions 211 is equal to the number of pressure relief mechanisms 3 arranged along the first wall 111 along the first direction X, and all sub-regions 211 have the same length. Taking N = 2 as an example, there are two sub-regions 211 in the main body 21, and the length of each sub-region 211 along the first direction X is L1 = L / 2.

[0152] L can be any point value among 400mm, 500mm, 600mm, 700mm, 800mm, 900mm, 1000mm, etc., or a range value between any two of them.

[0153] Along the thickness direction Z of the first wall portion, the projection of each pressure relief mechanism 3 is correspondingly located within a sub-region 211 . In other words, when viewed along the thickness direction Z of the first wall portion, each pressure relief mechanism 3 is blocked by a corresponding sub-region 211 .

[0154] The thickness direction Z of the first wall portion may be perpendicular to the first direction X, or may be arranged at an acute angle or an obtuse angle. As an example, in FIG5 , the thickness direction Z of the first wall portion is perpendicular to the first direction X.

[0155] For a typical battery cell 10, when the length of the main body 21 is greater than or equal to 400 mm, the large capacity requirement of the battery cell 10 can be met, but the pressure relief capability is poor, and untimely pressure relief is prone to occur. In this embodiment, the projection of each pressure relief mechanism 3 along the thickness direction Z of the first wall portion corresponds to a sub-region 211, so that each sub-region 211 can correspond to a pressure relief mechanism 3 on the housing 1. Each pressure relief mechanism 3 can discharge the emission medium generated by thermal runaway in the corresponding sub-region 211. If thermal runaway occurs in any sub-region 211 of the main body 21, the emission medium generated by the thermal runaway can be quickly discharged through the corresponding pressure relief mechanism 3, which can effectively improve the timely pressure relief of the battery cell 10 and thereby improve the reliability of the battery cell 10.

[0156] In some embodiments, the first wall portion 111 supports the main body portion 21 along the direction of gravity.

[0157] The thickness direction Z of the first wall portion can be parallel to the direction of gravity. The first wall portion 111 is the wall portion of the housing 1 that supports the main body portion 21 along the direction of gravity. The first wall portion 111 bears the weight of the main body portion 21. The first wall portion 111 can directly contact the main body portion 21 to support the main body portion 21, or an intermediate member can be provided between the first wall portion 111 and the main body portion 21 to support the main body portion 21 through the intermediate member. The intermediate member can be an insulating member provided between the first wall portion 111 and the main body portion 21.

[0158] In this embodiment, the first wall portion 111 supports the main body portion 21 along the direction of gravity, and the exhaust inside the housing 1 can be discharged from the bottom of the housing 1. Because the first wall portion 111 is the wall portion of the housing 1 that supports the main body portion 21, the first wall portion 111 is pressed by the main body portion 21, and the area inside the housing 1 near the first wall portion 111 is more prone to blockage and air suffocation, which is not conducive to the discharge of the exhaust medium. However, the provision of multiple pressure relief mechanisms 3 on the first wall portion 111 further facilitates the discharge of the exhaust medium inside the housing 1 near the first wall portion 111, thereby improving the reliability of the battery cell 10.

[0159] 5 , the housing 1 further includes a second wall portion 112. The first wall portion 111 and the second wall portion 112 are disposed opposite each other along the thickness direction Z of the first wall portion. The first wall portion 111 supports the main body portion 21 along the direction of gravity. A channel gap 13 is formed between the second wall portion 112 and the main body portion 21. The channel gap 13 is configured to connect the spaces inside the housing 1 located at both ends of the main body portion 21 along the first direction X.

[0160] The first wall portion 111 and the second wall portion 112 are two opposite wall portions of the housing 1 . The thicknesses of the first wall portion 111 and the second wall portion 112 may be equal or different.

[0161] A channel gap 13 is formed between the second wall portion 112 and the main body portion 21. The spaces within the housing 1 located at opposite ends of the main body portion 21 along the first direction X are a first space 14 and a second space 15, respectively. The channel gap 13 connects the first space 14 with the second space 15. In the event of thermal runaway of the battery cell 10, the exhaust medium from one of the first space 14 and the second space 15 can flow to the other through the channel gap 13.

[0162] In this embodiment, the channel gap 13 can connect the spaces inside the shell 1 at both ends of the main body 21 along the first direction X. When a sub-region 211 located at one end of the main body 21 experiences thermal runaway, the discharge medium accumulated near one end of the main body 21 can be discharged through the pressure relief mechanism 3 corresponding to the sub-region 211, and can also flow to the other end of the main body 21 through the channel gap 13 and be discharged through the pressure relief mechanism 3 corresponding to the sub-region 211 at the other end of the main body 21, so that the discharge medium inside the battery cell 10 can be quickly discharged, thereby improving the timeliness of the pressure relief of the battery cell 10.

[0163] In some embodiments, referring to FIG. 6 , FIG. 6 is a cross-sectional view of the housing 1 shown in FIG. 5 taken along the YZ plane. The housing 1 further includes a third wall portion 113 and a fourth wall portion 114 . The third wall portion 113 and the fourth wall portion 114 are disposed opposite each other along the second direction Y. The first wall portion 111 connects the third wall portion 113 and the fourth wall portion 114 . A plane formed by the intersection of the thickness direction Z of the first wall portion and the first direction X intersects the second direction Y. The thickness of the third wall portion 113 and the thickness of the fourth wall portion 114 are both less than the thickness of the first wall portion 111 .

[0164] A plane formed by the intersection of the thickness direction Z of the first wall and the first direction X intersects the second direction Y, so that the thickness direction Z of the first wall, the first direction X, and the second direction Y are not coplanar.

[0165] The thickness of the first wall portion 111 may be equal to the thickness of the second wall portion 112 ; the thickness of the first wall portion 111 may also be different from the thickness of the second wall portion 112 , for example, the thickness of the first wall portion 111 is greater than the thickness of the second wall portion 112 .

[0166] As an example, the second wall portion 112 connects the third wall portion 113 and the fourth wall portion 114, the distance between the inner surface of the first wall portion 111 and the inner surface of the second wall portion 112 is greater than the distance between the inner surface of the third wall portion 113 and the inner surface of the fourth wall portion 114, and the thickness of the first wall portion 111 is equal to the thickness of the second wall portion 112.

[0167] In this embodiment, the thickness of the third wall portion 113 and the thickness of the fourth wall portion 114 are both smaller than the thickness of the first wall portion 111, which can increase the thickness of the first wall portion 111, improve the deformation resistance of the first wall portion 111, and reduce the risk of excessive deformation of the first wall portion 111 due to expansion of the battery cell 10, thereby reducing the impact of the deformation of the first wall portion 111 on the pressure relief mechanism 3, reducing the risk of the pressure relief mechanism 3 opening for pressure relief in advance, and improving the service life of the pressure relief mechanism 3.

[0168] In some embodiments, the sum of the predetermined pressure relief areas of N pressure relief mechanisms 3 is S1. Along the thickness direction Z of the first wall portion, the first wall portion 111 has a first outer surface 1113 facing away from the main body portion 21. The area of ​​the first outer surface 1113 is S2, and 0.05≤S1 / S2≤0.55.

[0169] The predetermined pressure relief areas of the N pressure relief mechanisms 3 may be equal, or the predetermined pressure relief areas of at least two pressure relief mechanisms 3 may be different. The predetermined pressure relief area of ​​the pressure relief mechanism 3 is the maximum area that the pressure relief mechanism 3 is expected to be able to open.

[0170] Taking the first wall portion 111 as an example, in which two pressure relief mechanisms 3 are arranged along the first direction X, it can be understood that N=2, and the predetermined pressure relief area of ​​one pressure relief mechanism 3 is S 11 , the predetermined pressure relief area of ​​the other pressure relief mechanism 3 is S 12 , S1=S 11 +S 12 The area of ​​the first outer surface 1113 is the area of ​​the region defined by the outer edge of the first outer surface 1113 .

[0171] As an example, the first wall portion 111 is a rectangular wall portion, and the first outer surface 1113 of the first wall portion 111 is a rectangle. The length and width of the first outer surface 1113 of the first wall portion 111 are measured, and the area of ​​the first outer surface 1113 of the first wall portion 111 is calculated by multiplying the length and width of the first outer surface 1113. In an embodiment where the first wall portion 111 connects the third wall portion 113 and the fourth wall portion 114, the first outer surface 1113 of the first wall portion 111 and the outer surface of the third wall portion 113 may be connected via a rounded surface, and the first outer surface 1113 of the first wall portion 111 and the outer surface of the fourth wall portion 114 may be connected via another rounded surface.

[0172] In this embodiment, S1 / S2 can be any point value among 0.05, 0.1, 0.13, 0.15, 0.18, 0.2, 0.23, 0.25, 0.28, 0.3, 0.33, 0.35, 0.38, 0.4, 0.43, 0.45, 0.48, 0.5, 0.53, 0.55, etc., or a range value between any two of them.

[0173] In this embodiment, S1 / S2≥0.05, so that the total pressure relief area of ​​the N pressure relief mechanisms 3 is larger, which is beneficial to improving the pressure relief rate of the battery cell 10 and improving the timeliness of the pressure relief of the battery cell 10; S1 / S2≤0.55 is beneficial to improving the strength of the first wall portion 111.

[0174] In some embodiments, 0.15≤S1 / S2≤0.35.

[0175] In this embodiment, S1 / S2 can be any point value among 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, etc., or a range value between any two of them.

[0176] In some embodiments, the predetermined pressure relief areas of the N pressure relief mechanisms 3 are equal.

[0177] Taking the example of the first wall portion 111 being provided with two pressure relief mechanisms 3 arranged along the first direction X, it can be understood that N=2, and the predetermined pressure relief areas of the two pressure relief mechanisms 3 are equal.

[0178] In this embodiment, the predetermined pressure relief areas of the N pressure relief mechanisms 3 are equal, so that the pressure relief capabilities of all the pressure relief mechanisms 3 on the first wall portion 111 are substantially consistent, and the difficulty of forming each pressure relief mechanism 3 can be reduced.

[0179] In some embodiments, referring to FIG. 7 , FIG. 7 is a view of the battery cell 10 shown in FIG. 5 taken along the direction A. The housing 1 includes a first half 16 and a second half 17 . Along a first direction X, the portion from the mid-section W of the housing 1 to one end of the housing 1 constitutes the first half 16 , while the portion from the mid-section W to the other end of the housing 1 constitutes the second half 17 . Both the first half 16 and the second half 17 are provided with at least one pressure relief mechanism 3 . The first direction X is perpendicular to the mid-section W.

[0180] Along the first direction X, the housing 1 has two opposing end surfaces. The distances from the midsection W of the housing 1 to the two end surfaces are equal. The portion of the housing 1 between one end surface and the midsection W is a first half 16, and the portion of the housing 1 between the other end surface and the midsection W is a second half 17. In embodiments where the housing 11 is a hollow structure with an opening at one end along the first direction X, the surface of the end cap 12 facing the exterior of the housing 1 may be one end surface of the housing 1, and the surface of the wall of the housing 11 opposing the end cap 12 facing the exterior of the housing 1 may be the other end surface of the housing 1. In embodiments where the housing 11 is a hollow structure with openings at both opposing ends along the first direction X, the surface of one end cap 12 facing the exterior of the housing 1 may be one end surface of the housing 1, and the surface of the other end cap 12 facing the exterior of the housing 1 may be the other end surface of the housing 1.

[0181] The first half area 16 may be provided with one pressure relief mechanism 3 or multiple pressure relief mechanisms 3 ; the second half area 17 may be provided with one pressure relief mechanism 3 or multiple pressure relief mechanisms 3 .

[0182] When the battery cell 10 is in thermal runaway, pressure relief can be performed through the pressure relief mechanism 3 of the first half zone 16 and the pressure relief mechanism 3 of the second half zone 17, so that the discharge medium in the first half zone 16 in the outer shell 1 can be discharged more quickly through the pressure relief mechanism 3 of the first half zone 16, and the discharge medium in the second half zone 17 in the outer shell 1 can be discharged more quickly through the pressure relief mechanism 3 of the second half zone 17, thereby improving the timeliness of pressure relief of the battery cell 10.

[0183] In some embodiments, only two pressure relief mechanisms 3 are provided on the first wall portion 111 , and the two pressure relief mechanisms 3 are respectively located in the first half area 16 and the second half area 17 .

[0184] It can be understood that, among the two pressure relief mechanisms 3 , one pressure relief mechanism 3 is provided at the portion of the first wall portion 111 located in the first half area 16 , and the other pressure relief mechanism 3 is provided at the portion of the first wall portion 111 located in the second half area 17 .

[0185] In this embodiment, only two pressure relief mechanisms 3 are provided on the first wall portion 111, so that there are not too many pressure relief mechanisms 3 on the first wall portion 111. While achieving rapid pressure relief of the battery cell 10, the manufacturing cost of the battery cell 10 is reduced, which has better economy.

[0186] In some embodiments, please continue to refer to Figure 7, the pressure relief mechanism 3 is provided with a notched groove 31, along the first direction X, the length of the shell 1 is L2, and the minimum distance between the notched grooves 31 of two adjacent pressure relief mechanisms 3 is L3, L2>L, L3 / L2≥1 / 6.

[0187] The maximum distance between the end surfaces of the housing 1 along the first direction X is the length of the housing 1. If both end surfaces of the housing 1 are planar, the length of the housing 1 along the first direction X is measured based on the two end surfaces. If one or both end surfaces of the housing 1 have a convex or concave portion, the length of the housing 1 along the first direction X is measured based on the planar area of ​​the end surface. The minimum distance between the scored grooves 31 of two adjacent pressure relief mechanisms 3 is the distance between the two closest locations.

[0188] L3 / L2 can be any point value among 1 / 6, 1 / 5, 1 / 4, 1 / 3, 1 / 2, 2 / 3, etc., or any range value between the two.

[0189] In this embodiment, L3 / L2≥1 / 6, so that the minimum distance between the notched grooves of two adjacent pressure relief mechanisms 3 is not too small, so that each pressure relief mechanism 3 can correspond to a larger area of ​​the main body 21, fully utilizing each pressure relief mechanism 3 and improving the timeliness of pressure relief of the battery cell 10.

[0190] In some embodiments, L3 / L2≥1 / 4.

[0191] In this embodiment, L3 / L2 can be any point value among 1 / 4, 1 / 3, 5 / 12, 1 / 2, 7 / 12, 2 / 3, etc., or a range of values ​​between any two points.

[0192] In this embodiment, the distance between two adjacent pressure relief mechanisms 3 is further increased. If only two pressure relief mechanisms 3 are provided on the first wall portion 111, the two pressure relief mechanisms 3 are closer to the ends of the shell 11 along the first direction X, which is more conducive to the rapid discharge of the discharge medium located at both ends of the main body 21 in the shell 11.

[0193] In some embodiments, L2 ≥ 500 mm; and / or, L3 ≥ 300 mm.

[0194] L2 can be any value among 500mm, 550mm, 600mm, 650mm, 750mm, 800mm, etc., or a range between any two values. L3 can be any value among 300mm, 330mm, 350mm, 380mm, 400mm, 430mm, 450mm, etc., or a range between any two values.

[0195] L2 ≥ 500 mm. The housing 1 is relatively large in the first direction X, meeting the large-capacity requirements of the battery cell 10. L3 ≥ 300 mm ensures that the minimum distance between two adjacent pressure relief mechanisms 3 is not too small, allowing each pressure relief mechanism 3 to cover a larger area of ​​the main body 21. Exhaust media from a larger area of ​​the main body 21 can be discharged through the corresponding pressure relief mechanism 3, fully utilizing each pressure relief mechanism 3 and improving the timely pressure relief of the battery cell 10.

[0196] 7 , along the first direction X, the length of the housing 1 is L2, the pressure relief mechanism 3 is provided with notched grooves 31, and the sum of the maximum spans of the notched grooves 31 of the N pressure relief mechanisms 3 along the first direction X is D1, 0.2≤D1 / L2≤0.6.

[0197] The maximum span of the scored groove 31 along the first direction X is the distance between the two farthest positions of the scored groove 31 along the first direction X. The maximum spans of the scored grooves 31 along the first direction X of the N pressure relief mechanisms 3 on the first wall portion 111 may be equal, or the maximum spans of the scored grooves 31 along the first direction X of at least two pressure relief mechanisms 3 on the first wall portion 111 may be different. The scored groove 31 may be a groove extending along a closed trajectory, which may be circular, rectangular, etc.; the scored groove 31 may also be a groove along a non-closed trajectory, which may be straight, arc-shaped, U-shaped, H-shaped, V-shaped, L-shaped, X-shaped, Y-shaped, etc. The scored groove 31 may be located on the inner side of the pressure relief mechanism 3 (the side of the pressure relief mechanism 3 facing the main body 21 along the thickness direction Z of the first wall portion) or on the outer side of the pressure relief mechanism 3 (the side of the pressure relief mechanism 3 facing away from the main body 21 along the thickness direction Z of the first wall portion). It should be noted that, among the multiple pressure relief mechanisms 3 of the first wall portion 111, the notched grooves 31 of some of the pressure relief mechanisms 3 may be located on the inner side of the pressure relief mechanisms 3, and the notched grooves 31 of another part of the pressure relief mechanisms 3 may be located on the outer side of the pressure relief mechanisms 3, or the notched grooves 31 of all the pressure relief mechanisms 3 may be located on the inner side of the pressure relief mechanisms 3, or the notched grooves 31 of all the pressure relief mechanisms 3 may be located on the outer side of the pressure relief mechanisms 3.

[0198] Taking the case where only two pressure relief mechanisms 3 are provided on the first wall portion 111 as an example, the maximum span of the notched groove 31 of one pressure relief mechanism 3 along the first direction X is D2, and the maximum span of the notched groove 31 of the other pressure relief mechanism 3 along the first direction X is D3, where D1 = D2 + D3.

[0199] In this embodiment, D1 / L2 can be any point value among 0.2, 0.23, 0.25, 0.28, 0.3, 0.33, 0.35, 0.38, 0.4, 0.43, 0.45, 0.48, 0.5, 0.53, 0.55, 0.58, 0.6, etc., or a range value between any two of them.

[0200] In this embodiment, D1 / L2 ≥ 0.2, which increases the sum of the maximum spans of the scored grooves 31 of the multiple pressure relief mechanisms 3 on the first wall portion 111 along the first direction X. This increases the total pressure relief area of ​​the multiple pressure relief mechanisms 3 on the first wall portion 111, thereby improving the pressure relief rate of the battery cell 10. D1 / L2 ≤ 0.6 prevents the sum of the maximum spans of the scored grooves 31 of the multiple pressure relief mechanisms 3 on the first wall portion 111 along the first direction X from being too large, thereby improving the strength of the first wall portion 111.

[0201] In some embodiments, referring to FIG8 , which is a partial enlarged view of the housing 1 shown in FIG6 , the pressure relief mechanism 3 is provided with a notched groove 31 . A weakened portion 32 is formed in the region where the notched groove 31 is provided. The weakened portion 32 is configured to rupture to release pressure within the battery cell 10 .

[0202] The weak portion 32 is the portion of the pressure relief mechanism 3 that is weaker than the rest of the structure. After the notch 31 is formed on the pressure relief mechanism 3, the remaining portion of the pressure relief mechanism 3 corresponding to the notch 31 serves as the weak portion 32. This weak portion 32 can be the bottom wall of the notch 31. In the event of thermal runaway of the battery cell 10, the pressure relief mechanism 3 can rupture at the weak portion 32 to release pressure within the battery cell 10.

[0203] In this embodiment, a weak portion 32 is formed in the corresponding area of ​​the pressure relief mechanism 3 by providing a notched groove 31. The method for forming the weak portion 32 is simple. The weak portion 32 is a weaker area of ​​the pressure relief mechanism 3 and is more easily destroyed in the event of thermal runaway of the battery cell 10, thereby releasing pressure in a timely manner.

[0204] In some embodiments, please continue to refer to FIG. 8 , along the thickness direction Z of the first wall portion, the notch of the notch groove 31 faces away from the main body portion 21 (not shown in FIG. 8 ).

[0205] As an example, the notched groove 31 is disposed on the outer side of the pressure relief mechanism 3 so that the notch of the notched groove 31 faces the main body 21 .

[0206] In this embodiment, the notch of the notch groove 31 faces away from the main body 21. If the pressure relief mechanism 3 and the first wall portion 111 are integrally formed, it is convenient to process the notch groove 31 on the first wall portion 111. If the pressure relief mechanism 3 and the first wall portion 111 are separately arranged, it is convenient to install the pressure relief mechanism 3 on the first wall portion 111.

[0207] In other embodiments, along the thickness direction Z of the first wall portion, the opening of the scoring groove 31 faces the main body portion 21 .

[0208] As an example, the scored groove 31 is provided on the inner side of the pressure relief mechanism 3 so that the notch of the scored groove 31 faces the main body 21 .

[0209] In this embodiment, the notch of the notch groove 31 faces the main body 21 , so that the weak portion 32 is not easily torn when the first wall portion 111 is deformed due to expansion of the battery cell 10 , thereby improving the long-term reliability of the pressure relief mechanism 3 .

[0210] In some embodiments, the pressure relief mechanism 3 includes a pressure relief area 33 , which is configured to open when the weak portion 32 ruptures.

[0211] Pressure relief zone 33 is the portion of pressure relief mechanism 3 that can be opened after the weakened portion 32 is ruptured. Pressure relief zone 33 can be located along the edge of weakened portion 32. During pressure relief, pressure relief zone 33 can be opened by flipping over or detaching. The area of ​​pressure relief zone 33 is the predetermined pressure relief area of ​​pressure relief mechanism 3.

[0212] In this embodiment, the notched groove 31 can be a groove extending along a closed track; the notched groove 31 can also be a groove extending along a non-closed track, and the non-closed track can be arc-shaped, U-shaped, H-shaped, V-shaped, L-shaped, Y-shaped, X-shaped, etc.

[0213] In this embodiment, the weak portion 32 defines a pressure relief zone 33 . During pressure relief, the pressure relief zone 33 can be opened with the weak portion 32 as a boundary, thereby increasing the pressure relief area of ​​the pressure relief mechanism 3 .

[0214] In some embodiments, please refer to FIG9 , which is a partial view of the first wall portion 111 provided in some embodiments of the present application. The notched groove 31 is a groove extending along a closed trajectory, and the notched groove 31 is disposed around the pressure relief area 33 .

[0215] It can be understood that the notched groove 31 is an annular groove arranged around the pressure relief area 33 .

[0216] As an example, as shown in FIG9 , the notched groove 31 includes two first arc segments 311 and two first straight segments 312. The two first straight segments 312 are arranged in parallel. One first arc segment 311, one first straight segment 312, another first arc segment 311, and another first straight segment 312 are connected end to end. The center angles of the two first arc segments 311 are both 180°. The area of ​​the pressure relief zone 33 (the predetermined pressure relief area of ​​the pressure relief mechanism 3) is S 13 , S 13 =a×b+π×a 2 Wherein, a is the distance between the inner side of one first straight line segment 312 and the inner side of another first straight line segment 312 , and b is the length of the first straight line segment 312 . Both a and b can be measured on the surface where the notch of the notch 31 is located.

[0217] In this embodiment, the notched groove 31 is a groove extending along a closed trajectory. During the pressure relief process, after the pressure relief mechanism 3 is cracked along the notched groove 31 , the pressure relief area 33 can be separated from the first wall portion 111 , thereby increasing the pressure relief area and improving the pressure relief rate of the battery cell 10 .

[0218] In some embodiments, referring to Figures 10 and 11, Figure 10 is a partial view of the first wall portion 111 provided in some other embodiments of the present application; Figure 11 is a partial view of the first wall portion 111 provided in some other embodiments of the present application. The notched groove 31 is a groove extending along a non-closed trajectory.

[0219] As an example, as shown in FIG10 , the notched groove 31 is an H-shaped groove, and the notched groove 31 includes a second straight line segment 313 and two third straight line segments 314. The two third straight line segments 314 are arranged in parallel, and one end of the second straight line segment 313 is connected to the midpoint of one third straight line segment 314, and the other end of the second straight line segment 313 is connected to the midpoint of the other third straight line segment 314. The area of ​​the pressure relief zone 33 (the predetermined pressure relief area of ​​the pressure relief mechanism 3) is S 13 , S 13 =2×c×d. Here, c is the distance between the inner side of one third straight line segment 314 and the inner side of another third straight line segment 314, and d is the distance between one end of a third straight line segment 314 and the side of the second straight line segment 313 facing the end. Both c and d can be measured on the surface where the notch of the notch 31 is located.

[0220] As an example, as shown in FIG11 , the notched groove 31 is a double Y-shaped groove. The notched groove 31 includes a fourth straight segment 315 and a fifth straight segment 316. Both ends of the fourth straight segment 315 are connected to two fifth straight segments 316 arranged at a non-zero angle. Along the length direction of the fourth straight segment 315, the two fifth straight segments 316 located at one end of the fourth straight segment 315 are symmetrically arranged with the two fifth straight segments 316 located at the other end of the fourth straight segment 315. Along the width direction of the fourth straight segment 315, the two fifth straight segments 316 located on one side of the fourth straight segment 315 are symmetrically arranged with the two fifth straight segments 316 located on the other side of the fourth straight segment 315. Along the length direction of the fourth straight segment 315, the line connecting the free ends of the two fifth straight segments 316 is a first line 317; along the width direction of the fourth straight segment 315, the line connecting the free ends of the two fifth straight segments 316 is a second line 318. The area of ​​the pressure relief zone 33 (the predetermined pressure relief area of ​​the pressure relief mechanism 3) is S. 13 , S 13=(f+g)×e+k×h. Here, f is the length of the fourth straight line segment 315, g is the length of the first line 317, e is the distance between the first line 317 and the side of the fourth straight line segment 315 facing the first line 317, k is the length of the second line 318, and h is the distance between the connecting position of the two fifth straight line segments 316 at the end of the fourth straight line segment 315 facing the second line 318 and the second line 318. f, g, e, k, and h can all be measured on the surface where the notch of the notch groove 31 is located.

[0221] In some embodiments, please continue to refer to FIG. 6 and FIG. 8 , the pressure relief mechanism 3 and the first wall portion 111 are integrally formed.

[0222] In the embodiment where the pressure relief mechanism 3 is provided with a notched groove 31 , the pressure relief mechanism 3 may be composed of a weak portion 32 and a pressure relief area 33 , and the weak portion 32 , the pressure relief area 33 and the first wall portion 111 may be integrally formed, thereby enabling the pressure relief mechanism 3 and the first wall portion 111 to be integrally formed.

[0223] As an example, the housing 1 may include a first wall 111, a second wall 112, a third wall 113, and a fourth wall 114. The first wall 111 and the second wall 112 are arranged opposite each other along the thickness direction Z of the first wall, and the third wall 113 and the fourth wall 114 are arranged opposite each other along the second direction Y. The first wall 111, the third wall 113, the second wall 112, and the fourth wall 114 are connected end to end. The thickness direction Z of the first wall, the first direction X, and the second direction Y are perpendicular to each other. The third wall 113 and the fourth wall 114 may be the walls with the largest outer surface area in the housing 1.

[0224] In this embodiment, the pressure relief mechanism 3 and the first wall portion 111 are integrally formed, the pressure relief mechanism 3 has higher reliability, the connection process between the pressure relief mechanism 3 and the first wall portion 111 is omitted, and the production cost of the battery cell 10 can be reduced.

[0225] In some embodiments, referring to Figures 12 and 13 , Figure 12 is an exploded view of a battery cell 10 provided in other embodiments of the present application; Figure 13 is a cross-sectional view of the battery cell 10 shown in Figure 12 . The pressure relief mechanism 3 is provided separately from the first wall portion 111 . The first wall portion 111 is provided with a pressure relief hole 1111 . The pressure relief mechanism 3 is mounted on the first wall portion 111 and covers the pressure relief hole 1111 .

[0226] The pressure relief mechanism 3 and the housing 1 are separate components that are molded separately and then assembled together. The pressure relief mechanism 3 can be a component such as an explosion-proof disk, explosion-proof valve, or safety valve. The pressure relief mechanism 3 can be attached to the first wall portion 111 by bonding, welding, or other methods. When the battery cell 10 experiences thermal runaway, the pressure relief mechanism 3 opens at least a portion of the pressure relief holes 1111, allowing the exhaust medium within the battery cell 10 to be discharged through the pressure relief holes 1111, thereby relieving the pressure within the battery cell 10.

[0227] The pressure relief mechanism 3 covers the pressure relief hole 1111, obstructing it. Along the thickness direction Z of the first wall, the projection of the hole wall of the pressure relief hole 1111 can be entirely located on the pressure relief mechanism 3. The pressure relief mechanism 3 can be located on the side of the pressure relief hole 1111 facing the main body 21 along the thickness direction Z of the first wall, or on the side of the pressure relief hole 1111 facing away from the main body 21 along the thickness direction Z of the first wall. If the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 facing the main body 21 along the thickness direction Z of the first wall, the pressure relief mechanism 3 separates the pressure relief hole 1111 from the interior space of the outer shell 1. In the event of thermal runaway of the battery cell 10, the pressure relief mechanism 3 is destroyed, connecting the pressure relief hole 1111 to the interior space of the outer shell 1, and the exhaust medium inside the outer shell 1 can be discharged through the pressure relief hole 1111. If the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 away from the main body 21 along the thickness direction Z of the first wall portion, the pressure relief hole 1111 is connected to the internal space of the outer shell 1, and the pressure relief mechanism 3 separates the pressure relief hole 1111 from the external space of the outer shell 1. When the battery cell 10 thermally runs away, the pressure relief mechanism 3 is destroyed, and the pressure relief hole 1111 connects the internal space of the outer shell 1 with the external space of the outer shell 1. The discharge medium inside the outer shell 1 can be discharged through the pressure relief hole 1111.

[0228] As an example, as shown in Figures 12 and 13, the pressure relief mechanism 3 is a bursting disc, which is mounted on the first wall portion 111. The bursting disc is a sheet having at least a portion of its strength less than that of the first wall portion 111, and covers the pressure relief hole 1111. When the battery cell 10 experiences thermal runaway, the bursting disc is at least partially destroyed, thereby opening at least a portion of the pressure relief hole 1111 to release the pressure inside the battery cell 10.

[0229] In this embodiment, the pressure relief mechanism 3 is a component independent of the housing 1 . The pressure relief mechanism 3 and the housing 1 can be produced and assembled separately, which reduces production difficulty and increases efficiency.

[0230] In some embodiments, please refer to Figures 14 and 15. Figure 14 is a partial enlarged view of the battery cell 10 shown in Figure 13; Figure 15 is a cross-sectional view of the first wall portion 111 shown in Figure 14. The first wall portion 111 is provided with a first groove 1112. The first groove 1112 includes groove side surfaces 1112a and a first groove bottom surface 1112b. The groove side surfaces 1112a are arranged around the first groove bottom surface 1112b. The pressure relief hole 1111 is provided on the first groove bottom surface 1112b. The pressure relief mechanism 3 is provided in the first groove 1112 and abuts against the first groove bottom surface 1112b. A gap 5 is formed between the groove side surfaces 1112a and the pressure relief mechanism 3 along at least a portion of the circumference of the first groove 1112.

[0231] The first groove 1112 can be formed in the first wall portion 111 in a variety of ways, such as stamping, milling, laser etching, etc. The groove side surface 1112a is a closed structure extending along the circumference of the first groove 1112. Along the depth direction of the first groove 1112, the notch of the first groove 1112 is arranged opposite to the first groove bottom surface 1112b, and the depth direction of the first groove 1112 can be parallel to the thickness direction Z of the first wall portion. The first groove 1112 can be a polygonal groove, a circular groove, etc. If the first groove 1112 is a polygonal groove, the cross-section of the groove side surface 1112a is polygonal, and the first groove bottom surface 1112b can be polygonal; if the first groove 1112 is circular, the cross-section of the groove side surface 1112a is circular, and the first groove bottom surface 1112b can be circular. Among them, the cross-section of the groove side surface 1112a is perpendicular to the depth direction of the first groove 1112. The groove side surface 1112a may include multiple side surfaces, connected end to end along the circumference of the first groove 1112. The side surfaces may be parallel to the thickness direction Z of the first wall portion, or perpendicular to the first groove bottom surface 1112b. The side surfaces may also be inclined surfaces arranged at an obtuse angle to the first groove bottom surface 1112b. Of course, the side surfaces may be flat or arcuate. If the side surfaces are arcuate, the side surfaces may be arcuate surfaces with a centerline parallel to the thickness direction Z of the first wall portion, or may be arcuate surfaces with a centerline perpendicular to the thickness direction Z of the first wall portion.

[0232] The pressure relief mechanism 3 is disposed within the groove. The pressure relief mechanism 3 may be entirely within the first groove 1112, or partially within the first groove 1112 and partially outside the first groove 1112. There are various ways to connect the pressure relief mechanism 3 to the first wall portion 111, such as welding, bonding, etc. The pressure relief mechanism 3 may directly contact the first groove bottom surface 1112b, so that the pressure relief mechanism 3 directly abuts the first groove bottom surface 1112b; the pressure relief mechanism 3 may also indirectly abut the first groove bottom surface 1112b through an intermediate piece. For example, the pressure relief mechanism 3 may be welded to the groove bottom wall 1112c of the first groove 1112, so that the pressure relief mechanism 3 contacts the first groove bottom surface 1112b, so that the pressure relief mechanism 3 directly abuts the first groove bottom surface 1112b; or, for another example, the pressure relief mechanism 3 may be bonded to the groove bottom wall 1112c of the first groove 1112 via an adhesive layer, so that the pressure relief mechanism 3 indirectly abuts the first groove bottom surface 1112b via the adhesive layer.

[0233] The circumference of the first groove 1112 surrounds the depth direction of the first groove 1112. The circumference of the notch of the first groove 1112 is the circumference of the first groove 1112. The gap 5 may be formed between the groove side surface 1112a and the pressure relief mechanism 3 along a portion of the circumference of the first groove 1112, or the gap 5 may be formed between the groove side surface 1112a and the pressure relief mechanism 3 along the entire circumference of the first groove 1112. The pressure relief mechanism 3 has an outer peripheral surface 34 facing the groove side surface 1112a. The outer peripheral surface 34 is a closed structure extending along the circumference of the pressure relief mechanism 3. If a gap 5 is formed between a portion of the groove side surface 1112a along the circumference of the first groove 1112 and the outer circumferential surface 34 of the pressure relief mechanism 3, and no gap 5 is formed between the other portion of the groove side surface 1112a along the circumference of the first groove 1112 and the outer circumferential surface 34 of the pressure relief mechanism 3, then a gap 5 is formed between a portion of the groove side surface 1112a along the circumference of the first groove 1112 and the pressure relief mechanism 3, and the gap 5 is a non-closed structure extending along the circumference of the first groove 1112; if a gap 5 is formed between the entire groove side surface 1112a along the circumference of the first groove 1112 and the outer circumferential surface 34 of the pressure relief mechanism 3, then a gap 5 is formed between the entire groove side surface 1112a along the circumference of the first groove 1112 and the pressure relief mechanism 3, and the gap 5 is a closed structure extending along the circumference of the first groove 1112, that is, the gap 5 is an annular gap.

[0234] As an example, the pressure relief mechanism 3 is provided with a notched groove 31 to form a corresponding weak portion 32 (not shown in FIG. 14 and FIG. 15 ).

[0235] When the first wall portion 111 is deformed due to the expansion of the battery cell 10, the gap 5 between the pressure relief mechanism 3 and the groove side 1112a can provide a buffer space for the pressure relief mechanism 3, reducing the risk of the groove side 1112a squeezing the pressure relief mechanism 3 and causing deformation of the pressure relief mechanism 3, thereby reducing the risk of the pressure relief mechanism 3 opening prematurely during normal use of the battery cell 10 and improving the service life of the pressure relief mechanism 3.

[0236] In some embodiments, please refer to Figures 16 and 17. Figure 16 is an assembly diagram of the pressure relief mechanism 3 and the first wall portion 111 provided in some embodiments of the present application; Figure 17 is a schematic structural diagram of the first wall portion 111 shown in Figure 16. The groove side surface 1112a includes a first region 1112d that forms a gap 5 with the pressure relief mechanism 3. Along the circumference of the first groove 1112, the length of the first region 1112d is L4, and the circumference of the groove side surface 1112a is L5, satisfying the following: 0.2≤L4 / L5≤1.

[0237] The length of the first region 1112d is the total length of the portion of the groove side surface 1112a that forms the gap 5 with the pressure relief mechanism 3 along the circumference of the first groove 1112. When measuring the length of the first region 1112d and the circumference of the groove side surface 1112a, the measurements can be taken along the edge of the groove side surface 1112a at the notch of the first groove 1112.

[0238] L4 / L5 can be any point value among 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc., or a range value between any two.

[0239] As an example, the groove side surface 1112a includes two first side surfaces 1112e and two second side surfaces 1112f. The two first side surfaces 1112e are arranged opposite each other along the second direction Y, and the two second side surfaces 1112f are arranged opposite each other along the first direction X. One first side surface 1112e, one second side surface 1112f, another first side surface 1112e, and another second side surface 1112f are sequentially connected end to end to form a closed structure. The first side surface 1112e extends along the first direction X of the first wall portion 111, and the second side surface 1112f is an arcuate surface. A gap 5 is formed between the two first side surfaces 1112e and the pressure relief mechanism 3, and only a portion of each second side surface 1112f forms a gap 5 with the pressure relief mechanism 3. It can be understood that the parts of the two second side surfaces 1112f and the pressure relief mechanism 3 forming the gap 5 and the two first side surfaces 1112e constitute the first area 1112d. Along the circumference of the first groove 1112, the total length of the parts of the two second side surfaces 1112f and the pressure relief mechanism 3 forming the gap 5 and the two first side surfaces 1112e is the length of the first area 1112d, and the total length of the two first side surfaces 1112e and the two second side surfaces 1112f is the circumference of the groove side surface 1112a.

[0240] In this embodiment, 0.2≤L4 / L5≤1, so that a gap 5 is formed between the longer part of the groove side surface 1112a in the circumferential direction and the pressure relief mechanism 3, reducing the extrusion range of the groove side surface 1112a on the pressure relief mechanism 3 when the first wall portion 111 is deformed, and further reducing the risk of the pressure relief mechanism 3 opening prematurely during normal use of the battery cell 10.

[0241] In some embodiments, please refer to FIG18 , which is an assembly diagram of the pressure relief mechanism 3 and the first wall portion 111 provided in some other embodiments of the present application. A gap 5 is formed between the groove side surface 1112a and the pressure relief mechanism 3 along the entire circumference of the first groove 1112.

[0242] It is understood that the gap 5 formed between the groove side surface 1112a and the outer peripheral surface 34 of the pressure relief mechanism 3 is an annular gap extending along the circumference of the first groove 1112. In this embodiment, the first area 1112d is the groove side surface 1112a, and L4 / L5=1.

[0243] In this embodiment, there is a gap 5 around the entire circumference of the groove side 1112a and the pressure relief mechanism 3. The gap 5 is an annular structure surrounding the pressure relief mechanism 3, further reducing the squeezing effect of the groove side 1112a on the pressure relief mechanism 3 when the first wall portion 111 is deformed, further reducing the risk of the pressure relief mechanism 3 opening prematurely during normal use of the battery cell 10.

[0244] In some embodiments, please refer to FIG19 , which is a partial view of a battery cell 10 provided in some other embodiments of the present application. The pressure relief mechanism 3 is welded to the bottom wall 1112 c of the first groove 1112 to form a first weld mark 6 .

[0245] The bottom wall 1112c of the first groove 1112 is a substantial portion of the pressure relief mechanism 3, located below the first groove bottom surface 1112b along the depth direction of the first groove 1112, and having a thickness. The first weld mark 6 is formed at the weld area between the pressure relief mechanism 3 and the bottom wall 1112c. The first weld mark 6 can be formed by fusing a portion of the pressure relief mechanism 3 and a portion of the bottom wall 1112c together. The weld mark can be an annular structure extending along the circumference of the pressure relief mechanism 3, a multi-segment structure spaced apart along the circumference of the pressure relief mechanism 3, or a long strip-shaped structure extending along a straight path.

[0246] In this embodiment, the pressure relief mechanism 3 is welded to the bottom wall 1112 c of the first groove 1112 , thereby fixing the pressure relief mechanism 3 to the first wall portion 111 and improving the connection strength between the pressure relief mechanism 3 and the first wall portion 111 .

[0247] In some embodiments, along the thickness direction Z of the first wall portion, the projection of the first weld print 6 is entirely located on the pressure relief mechanism 3 .

[0248] When viewed along the thickness direction Z of the first wall portion, the weld mark is entirely located within the region defined by the outer edge of the pressure relief mechanism 3, and no portion of the weld mark is located outside the region defined by the outer edge of the pressure relief mechanism 3. The weld mark includes a portion located within the pressure relief mechanism 3 and a portion located within the groove bottom wall 1112c.

[0249] In this embodiment, the pressure relief mechanism 3 can be welded to the bottom wall 1112c of the first groove 1112 by penetration welding. This simple welding method allows the first weld mark 6 formed after welding to pass through the pressure relief mechanism 3 and embed into the bottom wall 1112c of the first groove 1112, thereby improving the connection strength between the pressure relief mechanism 3 and the first wall portion 111. Furthermore, because the projection of the first weld mark 6 along the thickness direction Z of the first wall portion is located on the pressure relief mechanism 3, the first weld mark 6 does not protrude from the edge of the pressure relief mechanism 3 and is not located within the gap 5 between the pressure relief mechanism 3 and the groove side surface 1112a. This reduces the risk of the groove side surface 1112a squeezing the pressure relief mechanism 3 through the first weld mark 6 when the first wall portion 1111 deforms.

[0250] In some embodiments, please continue to refer to FIG. 19 , along the thickness direction Z of the first wall portion, the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 away from the main body portion 21 .

[0251] It is understandable that, along the thickness direction Z of the first wall, the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 away from the interior of the housing 1. The side of the pressure relief hole 1111 away from the interior of the housing 1 is the side of the pressure relief hole 1111 facing the outside of the housing 1.

[0252] In this embodiment, the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 away from the main body 21. The pressure relief mechanism 3 can be installed on the outside of the first wall 111, making it more convenient to install the pressure relief mechanism 3.

[0253] In some embodiments, the battery cell 10 further includes a protective member 7 . Along the thickness direction Z of the first wall portion, the protective member 7 is located on a side of the pressure relief mechanism 3 away from the main body 21 , and the protective member 7 covers the first groove 1112 .

[0254] Along the thickness direction Z of the first wall portion, the side of the pressure relief mechanism 3 facing away from the main body portion 21 is the outer side of the pressure relief mechanism 3. The protective member 7 covers the first groove 1112, so that the notch of the first groove 1112 is blocked by the protective member 7. Along the thickness direction Z of the first wall portion, the projection of the notch of the first groove 1112 is entirely located on the protective member 7. The protective member 7 can be a flat plate structure. The protective member 7 can be made of metal, such as copper, iron, aluminum, steel, aluminum alloy, etc. The protective member 7 can also be made of non-metallic materials, such as plastic, rubber, etc. The protective member 7 is fixed to the first wall portion 111. The protective member 7 can be fixed to the first wall portion 111 by welding, bonding, etc.

[0255] In this embodiment, the protective member 7 can protect the pressure relief mechanism 3 and reduce the risk of external substances (impurities, electrolyte) entering the first groove 1112 and corroding the pressure relief mechanism 3.

[0256] In some embodiments, along the thickness direction Z of the first wall portion, the first wall portion 111 has a first outer surface 1113 facing away from the main body portion 21, the first outer surface 1113 is provided with a second groove 1114, the first groove 1112 is provided on the bottom surface of the second groove 1114, and the protective member 7 is at least partially accommodated in the second groove 1114.

[0257] The first outer surface 1113 of the first wall portion 111 may be the surface of the first wall portion 111 farthest from the main body portion 21 along the thickness direction. The bottom surface of the second groove 1114 may be the first surface 1115. The first groove 1112 is disposed on the first surface 1115. The protective member 7 may abut against the first surface 1115 so that the protective member 7 covers the first groove 1112. The second groove 1114 may be a polygonal groove, a circular groove, or the like. The protective member 7 may be partially or completely contained within the second groove 1114.

[0258] In this embodiment, the first wall portion 111 is provided with a second groove 1114, and the protective member 7 is at least partially located in the second groove 1114, which can reduce the height of the protective member 7 protruding from the first outer surface 1113 of the first wall portion 111 and reduce the space occupied by the protective member 7 outside the shell 1.

[0259] In some embodiments, please refer to FIG20 , which is a partial view of a battery cell 10 provided in some other embodiments of the present application. Along the thickness direction Z of the first wall, the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 facing the main body 21 .

[0260] It can be understood that the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 facing the interior of the housing 1 .

[0261] In this embodiment, the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 facing the main body 21. The pressure relief mechanism 3 can be installed on the inner side of the first wall portion 111. The first wall portion 111 can protect the pressure relief mechanism 3 and reduce the risk of the first wall portion 111 being damaged by external components.

[0262] In some embodiments, the battery cell 10 further includes a protective member 7 . Along the thickness direction Z of the first wall portion, the protective member 7 is located on a side of the pressure relief hole 1111 away from the main body 21 and covers the pressure relief hole 1111 .

[0263] Along the thickness direction Z of the first wall portion, the side of the pressure relief hole 1111 facing away from the main body portion 21 is the side of the pressure relief hole 1111 facing the outside of the housing 1. Along the thickness direction Z of the first wall portion, the pressure relief mechanism 3 and the protective member 7 are respectively located on either side of the pressure relief hole 1111. The pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 facing the interior of the housing 1, and the protective member 7 is located on the side of the pressure relief hole 1111 facing away from the interior of the housing 1.

[0264] The protective member 7 covers the pressure relief hole 1111 , and the protective member 7 blocks the pressure relief hole 1111 . Along the thickness direction Z of the first wall portion, the projection of the hole wall surface of the pressure relief hole 1111 can be entirely located on the protective member 7 .

[0265] As an example, along the thickness direction Z of the first wall portion, a protrusion 1116 arranged around the pressure relief hole 1111 is formed on the side of the first wall portion 111 facing away from the electrode assembly 2 , and the protective member 7 is fixed to the protrusion 1116 to cover the pressure relief hole 1111 .

[0266] In this embodiment, the protective member 7 can protect the pressure relief mechanism 3 and reduce the risk of external substances (impurities, electrolyte) entering the pressure relief hole 1111 and corroding the pressure relief mechanism 3.

[0267] In some embodiments, please refer to Figures 21 and 22. Figure 21 is an exploded view of the housing 1 provided in some embodiments of the present application; Figure 22 is an exploded view of the housing 1 provided in other embodiments of the present application. The housing 1 includes a shell 11 and an end cap 12. The shell 11 has an opening formed at least at one end along a first direction X. The shell 11 includes a first wall portion 111. The end cap 12 corresponds to the opening one-to-one and seals the opening.

[0268] A first wall portion 111 is formed in the housing 11 and is at least a portion of the housing 11. The housing 11 may have a cylindrical shape, a polygonal prism, or other shapes. In embodiments where the housing 11 is cylindrical, the entire cylindrical sidewall of the housing 11 may serve as the first wall portion 111. In embodiments where the housing 11 is a polygonal prism, one of the walls of the housing 11 may serve as the first wall portion 111. As an example, in Figures 21 and 22, the housing 11 is a rectangular parallelepiped, and one of the walls of the housing 11 serves as the first wall portion 111.

[0269] In the embodiment shown in FIG. 21 , the shell 11 is a hollow structure with openings formed at both ends along the first direction X; in the embodiment shown in FIG. 22 , the shell 11 is a hollow structure with an opening formed at one end along the first direction X.

[0270] When assembling the battery cell 10, the electrode assembly 2 can be first installed in the housing 11, and then the opening of the housing 11 can be sealed with the end cap 12, making assembly of the battery cell 10 convenient and quick. Because the first wall 111 is formed on the housing 11, the pressure relief mechanism 3 is located on the housing 11, reducing the impact of the discharge medium discharged from the battery cell 10 when the pressure is relieved by the pressure relief mechanism 3 on the components outside the end cap 12, such as the busbar components and detection components electrically connected to the electrode terminals 4 on the end cap 12.

[0271] In some embodiments, referring to FIG. 21 , openings are formed at opposite ends of the housing 11 along the first direction X.

[0272] It can be understood that there are two end covers 12 in the housing 1 , and the two end covers 12 respectively close the two openings of the shell 11 .

[0273] As an example, along the first direction X, both ends of the main body 21 (not shown in FIG. 21 ) are provided with tabs 22 (not shown in FIG. 21 ), and the tabs 22 at both ends of the main body 21 have opposite polarities. Both end caps 12 of the housing 1 are provided with electrode terminals 4 (not shown in FIG. 21 ). Along the first direction X, the electrode terminal 4 on one end cap 12 is electrically connected to the tab 22 at one end of the main body 21, and the electrode terminal 4 on the other end cap 12 is electrically connected to the tab 22 at the other end of the main body 21.

[0274] In this embodiment, openings are formed at both opposite ends of the shell 11 along the first direction X. When assembling the battery cell 10, the electrode assembly 2 can enter the shell 11 from any end of the shell 11, which can effectively improve the assembly efficiency of the battery cell 10.

[0275] In some embodiments, please refer to Figure 23, which is a schematic structural diagram of the housing 11 shown in Figure 21. The housing 11 is an integrally formed structure.

[0276] As an example, the housing 1 may include a first wall portion 111, a second wall portion 112, a third wall portion 113, and a fourth wall portion 114. The first wall portion 111 and the second wall portion 112 are arranged opposite each other along the thickness direction Z of the first wall portion, and the third wall portion 113 and the fourth wall portion 114 are arranged opposite each other along the second direction Y. The first wall portion 111, the third wall portion 113, the second wall portion 112, and the fourth wall portion 114 are connected end to end, and the thickness direction Z of the first wall portion, the first direction X, and the second direction Y are perpendicular to each other. The first wall portion 111, the second wall portion 112, the third wall portion 113, and the fourth wall portion 114 are integrally formed. The housing 1 can be formed from a sheet material by stamping or stretching.

[0277] In this embodiment, the housing 11 is an integrally formed structure, which can improve the strength of the housing 11 , improve the anti-destruction capability of the housing 11 , and increase the service life of the housing 11 .

[0278] In some embodiments, please refer to Figures 24-26. Figure 24 is a schematic structural diagram of the housing 11 provided in other embodiments of the present application; Figure 25 is a cross-sectional view of the housing 11 shown in Figure 24 taken along the YZ plane; and Figure 26 is an expanded view of the housing 11 shown in Figure 25. The housing 11 is formed by bending a sheet material, with the front and rear ends of the sheet material connected to each other along the circumference of the opening of the housing 11.

[0279] Taking the shell 11 including the first wall portion 111 , the third wall portion 113 , the second wall portion 112 and the fourth wall portion 114 as an example, the first wall portion 111 , the third wall portion 113 , the second wall portion 112 and the fourth wall portion 114 are arranged in sequence along the circumference of the opening.

[0280] Along the circumference of the opening, the plate has two opposing ends, namely a first end 1121 and a second end 1122. As shown in FIG26 , before the shell 11 is formed, the plate has two opposing end surfaces, namely a first end surface 1121a and a second end surface 1122a. The portion of the plate within a region of a first preset distance L6 offset from the first end surface 1121a in a direction close to the second end surface 1122a is the plate's first end 1121, and the length of the first end 1121 is equal to the first preset distance L6. The portion of the plate within a region of a second preset distance L7 offset from the second end surface 1122a in a direction close to the first end surface 1121a is the plate's second end 1122, and the length of the second end 1122 is equal to the second preset distance L7. The first preset distance L6 and the second preset distance L7 can be equal or different.

[0281] The two ends of the plate (the first end 1121 and the second end 1122) can be connected in various ways, such as welding, bonding, hot melt connection, etc. The connection position of the two ends can be located on a wall portion of the housing 11, for example, the connection position of the two ends is located on the first wall portion 111, the second wall portion 112, the third wall portion 113, or the fourth wall portion 114; the connection position of the two ends can also be located at the intersection of two adjacent walls of the housing 11, and the intersection is the corner area of ​​the housing 11.

[0282] When forming the shell 11 , it is only necessary to bend the plate and connect the two ends of the plate to each other. The forming method of the shell 11 is simple and can effectively reduce the difficulty of forming the shell 11 .

[0283] In some embodiments, two ends of the plate are connected by welding to form a second weld print 115 .

[0284] Second weld marks 115 are formed at the welding locations of the two ends. Second weld marks 115 may be the portion where the two ends are fused together. If the first end surface 1121a and the second end surface 1122a are positioned opposite each other, the two ends may be welded using a seam weld. If the two ends overlap along the thickness direction Z of the first wall, penetration welding may be used in the overlapping region.

[0285] In this embodiment, the two ends of the plate are connected by welding, so that the two ends have good connection strength, and the two ends are more firmly connected.

[0286] In some embodiments, the housing 11 further includes a second wall portion 112 , and the first wall portion 111 and the second wall portion 112 are disposed opposite to each other along the thickness direction Z of the first wall portion. The second weld mark 115 is located on the second wall portion 112 .

[0287] As an example, the first and second ends of the plate together form the second wall portion 112 , that is, a portion of the second wall portion 112 is the first end portion 1121 , and the other portion of the second wall portion 112 is the second end portion 1122 .

[0288] In this embodiment, the second weld mark 115 is located on the second wall 112, so that the second weld mark 115 and the pressure relief mechanism 3 are located on two opposing walls of the housing 11. This reduces the impact of the two ends of the plate material on the pressure relief mechanism 3 during welding, thereby improving the reliability of the pressure relief mechanism 3. In embodiments where the third wall 113 and the fourth wall 114 are the walls with the largest outer surface area in the housing 1, when the electrode assembly 2 expands, the first wall 111 and the second wall 112 are less affected by the electrode assembly 2 than the third wall 113 and the fourth wall 114. The deformation of the first wall 111 and the second wall 112 is smaller than that of the third wall 113 and the fourth wall 114. Since the second weld mark 115 is located on the second wall 112, the impact of the expansion of the electrode assembly 2 on the second weld mark 115 is reduced, reducing the risk of damage to the housing 11 due to the expansion of the electrode assembly 2 at the location of the second weld mark 115.

[0289] In some embodiments, the housing 1 is in a rectangular parallelepiped shape, and the first direction X is parallel to the length direction of the housing 1 .

[0290] As an example, the length of the housing 1 is greater than or equal to the height and width of the housing 1 .

[0291] In this embodiment, the outer shell 1 is in the shape of a rectangular parallelepiped. The outer shell 1 has a simple structure and is easy to form. When the battery cells 10 are applied to the battery 100, the outer shell 1 of the battery cells 10 is in the shape of a rectangular parallelepiped. This can reduce the installation gap between the battery cells 10, which is conducive to improving the volume energy density of the battery 100.

[0292] An embodiment of the present application provides a battery 100 , which is the battery cell 10 provided in any one of the above embodiments.

[0293] An embodiment of the present application provides an electrical device, and the battery cell 10 provided in any one of the above embodiments is used to provide electrical energy to the electrical device.

[0294] The embodiment of the present application also provides a battery cell 10, comprising a housing 1 and an electrode assembly 2, wherein the electrode assembly 2 is housed within the housing 1. The housing 1 is a rectangular parallelepiped, comprising a shell 11 and two end caps 12. An opening is formed at opposite ends of the housing 11 along a first direction X, with each end cap 12 enclosing one opening. The housing 11 comprises a first wall 111, a second wall 112, a third wall 113, and a fourth wall 114. The first wall 111, the third wall 113, the second wall 112, and the fourth wall 114 are connected end to end in sequence. The first wall 111 and the second wall 112 are disposed opposite each other along a thickness direction Z of the first wall, and the third wall 113 and the fourth wall 114 are disposed opposite each other along a second direction Y. The thickness direction Z of the first wall intersects the first direction X, and a plane formed by the intersection of the thickness direction Z of the first wall and the first direction X intersects the second direction Y. The electrode assembly 2 includes a main body 21 and tabs 22. Tabs 22 are provided at opposite ends of the main body 21 along a first direction X. Both end caps 12 are provided with electrode terminals 4. The tab 22 at one end of the main body 21 is electrically connected to the electrode terminal 4 on one end cap 12, and the tab 22 at the other end of the main body 21 is electrically connected to the electrode terminal 4 on the other end cap 12. A first wall 111 supports the main body 21 in the direction of gravity. A channel gap 13 is formed between the second wall 112 and the main body 21. The channel gap 13 is configured to connect the spaces within the housing 1 located at both ends of the main body 21 along the first direction X. The thickness of the first wall 111 is equal to that of the second wall 112. The thickness of the third wall 113 and the fourth wall 114 are both less than that of the first wall 111. The first wall portion 111 is provided with N pressure relief mechanisms 3 arranged along a first direction X. The main body portion 21 includes multiple sub-regions 211, which are arranged continuously along the first direction X. The main body portion 21 has a length of L, and the sub-regions 211 have a length of L1, where L = L1 × N, L ≥ 400 mm, and N = 2. Along the thickness direction Z of the first wall portion, the projection of each pressure relief mechanism 3 is located within a corresponding sub-region 211. The sum of the predetermined pressure relief areas of the N pressure relief mechanisms 3 is S1, and the predetermined pressure relief areas of the N pressure relief mechanisms 3 are equal. Along the thickness direction Z of the first wall portion, the first wall portion 111 has a first outer surface 1113 facing away from the main body portion 21. The area of ​​the first outer surface 1113 is S2, and 0.05 ≤ S1 / S2 ≤ 0.55.

[0295] 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.

[0296] 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: The housing comprises a first wall portion, wherein the first wall portion is provided with N pressure relief mechanisms arranged along a first direction; An electrode assembly is contained in the housing, the electrode assembly comprises a main body and a tab, at least one end of the main body is provided with the tab, the main body comprises a plurality of sub-regions, and the plurality of sub-regions are continuously provided along the first direction, the length of the main body is L, the length of the sub-region is L1, L=L1×N, L≥400mm, N≥2; Wherein, along the thickness direction of the first wall portion, the projection of each of the pressure relief mechanisms is correspondingly located within one of the sub-regions, and the thickness direction of the first wall portion intersects with the first direction.

2. The battery cell according to claim 1, wherein: The first wall portion supports the main body portion along a gravity direction.

3. The battery cell according to claim 2, wherein: The shell also includes a second wall portion, and the first wall portion and the second wall portion are arranged opposite to each other along the thickness direction of the first wall portion. A channel gap is formed between the second wall portion and the main body portion, and the channel gap is configured to connect the space inside the shell located at both ends of the main body portion along the first direction.

4. The battery cell according to any one of claims 1 to 3, wherein: The housing further comprises a third wall portion and a fourth wall portion, the third wall portion and the fourth wall portion are arranged opposite to each other along a second direction, the first wall portion connects the third wall portion and the fourth wall portion, and a plane formed by the intersection of the thickness direction of the first wall portion and the first direction intersects with the second direction; Wherein, the thickness of the third wall portion and the thickness of the fourth wall portion are both smaller than the thickness of the first wall portion.

5. The battery cell according to any one of claims 1 to 4, wherein: The sum of the predetermined pressure relief areas of the N pressure relief mechanisms is S1. Along the thickness direction of the first wall portion, the first wall portion has a first outer surface away from the main body portion. The area of ​​the first outer surface is S2, and 0.05≤S1 / S2≤0.

55.

6. The battery cell according to claim 5, wherein: 0.15≤S1 / S2≤0.

35.

7. The battery cell according to claim 5 or 6, wherein: The predetermined pressure relief areas of the N pressure relief mechanisms are equal.

8. The battery cell according to any one of claims 1 to 7, wherein: The shell includes a first half area and a second half area. Along the first direction, the part from the middle section of the shell to one end of the shell is the first half area, and the part from the middle section of the shell to the other end of the shell is the second half area. The first half area and the second half area are both provided with at least one pressure relief mechanism, and the first direction is perpendicular to the middle section.

9. The battery cell according to claim 8, wherein: The first wall portion is provided with only two pressure relief mechanisms, and the two pressure relief mechanisms are respectively located in the first half area and the second half area.

10. The battery cell according to any one of claims 1 to 9, wherein: The pressure relief mechanism is provided with a notched groove. Along the first direction, the length of the shell is L2. The minimum distance between the notched grooves of two adjacent pressure relief mechanisms is L3. L2>L, L3 / L2≥1 / 6.

11. The battery cell according to claim 10, wherein: L3 / L2≥1 / 4.

12. The battery cell according to claim 10 or 11, wherein: L2 ≥ 500 mm; and / or, L3 ≥ 300 mm.

13. The battery cell according to any one of claims 1 to 12, wherein: Along the first direction, the length of the shell is L2, the pressure relief mechanism is provided with a notched groove, and the sum of the maximum spans of the notched grooves of N pressure relief mechanisms along the first direction is D1, 0.2≤D1 / L2≤0.

6.

14. The battery cell according to any one of claims 1 to 13, wherein: The pressure relief mechanism is provided with a notch groove, and a weak portion is formed in a region where the notch groove is provided, and the weak portion is configured to be able to rupture to release the pressure inside the battery cell.

15. The battery cell according to claim 14, wherein: Along the thickness direction of the first wall portion, the notch of the notch groove faces the main body portion.

16. The battery cell according to claim 14 or 15, wherein: The pressure relief mechanism includes a pressure relief zone configured to open when the weak portion ruptures.

17. The battery cell according to claim 16, wherein: The notched groove is a groove extending along a closed track, and the notched groove is arranged around the pressure relief area.

18. The battery cell according to any one of claims 1 to 17, wherein: The pressure relief mechanism is integrally formed with the first wall portion.

19. The battery cell according to any one of claims 1 to 17, wherein: The pressure relief mechanism is separately provided with the first wall portion, the first wall portion is provided with a pressure relief hole, and the pressure relief mechanism is installed on the first wall portion and covers the pressure relief hole.

20. The battery cell according to claim 19, wherein: The first wall portion is provided with a first groove, the first groove includes a groove side surface and a first groove bottom surface, the groove side surface is arranged around the first groove bottom surface, the pressure relief hole is arranged on the first groove bottom surface, and the pressure relief mechanism is arranged in the first groove and abuts against the first groove bottom surface; Wherein, a gap is formed between at least a portion of the groove side surface along the circumference of the first groove and the pressure relief mechanism.

21. The battery cell according to claim 20, wherein: The groove side surface includes a first area forming a gap with the pressure relief mechanism. Along the circumference of the first groove, the length of the first area is L4, and the circumference of the groove side surface is L5, satisfying: 0.2≤L4 / L5≤1.

22. The battery cell according to claim 20 or 21, wherein: A gap is formed between the groove side surface and the pressure relief mechanism along the entire circumference of the first groove.

23. The battery cell according to any one of claims 20 to 22, wherein: The pressure relief mechanism is welded to the bottom wall of the first groove to form a first weld mark.

24. The battery cell according to claim 23, wherein: Along the thickness direction of the first wall portion, projections of the first welded portions are all located on the pressure relief mechanism.

25. The battery cell according to any one of claims 20 to 24, wherein: Along the thickness direction of the first wall portion, the pressure relief mechanism is located at a side of the pressure relief hole away from the main body portion.

26. The battery cell according to claim 25, wherein: The battery cell further includes a protective member, which is located on a side of the pressure relief mechanism away from the main body along a thickness direction of the first wall portion, and covers the first groove.

27. The battery cell according to claim 26, wherein: Along the thickness direction of the first wall portion, the first wall portion has a first outer surface away from the main body portion, the first outer surface is provided with a second groove, the first groove is arranged at the groove bottom surface of the second groove, and the protective member is at least partially accommodated in the second groove.

28. The battery cell according to any one of claims 20 to 24, wherein: Along the thickness direction of the first wall portion, the pressure relief mechanism is located on a side of the pressure relief hole facing the main body portion.

29. The battery cell according to claim 28, wherein: The battery cell further includes a protective member, which is located on a side of the pressure relief hole away from the main body portion along a thickness direction of the first wall portion and covers the pressure relief hole.

30. The battery cell according to any one of claims 1 to 29, wherein: The housing comprises: A housing, at least one end of which is formed with an opening along the first direction, and the housing includes the first wall portion; The end covers correspond to the openings one by one, and the end covers close the openings.

31. The battery cell according to claim 30, wherein: The openings are formed at two opposite ends of the shell along the first direction.

32. The battery cell according to claim 30 or 31, wherein: The shell is an integrally formed structure.

33. The battery cell according to claim 30 or 31, wherein: The shell is formed by bending a plate, and along the circumference of the opening, the first and second ends of the plate are connected to each other.

34. The battery cell according to claim 33, wherein: The two end portions are connected by welding to form a second weld mark.

35. The battery cell according to claim 34, wherein: The housing further includes a second wall portion, and along a thickness direction of the first wall portion, the first wall portion and the second wall portion are arranged opposite to each other; Wherein, the second welding portion is located on the second wall portion.

36. The battery cell according to any one of claims 1 to 35, wherein: The shell is in a rectangular parallelepiped shape, and the first direction is parallel to the length direction of the shell.

37. A battery comprising the battery cell according to any one of claims 1 to 36.

38. An electrical device, comprising the battery cell according to any one of claims 1 to 36, wherein the battery cell is used to provide electrical energy to the electrical device.

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