Battery monomer, battery and electric equipment

Abstract

The embodiment of the utility model provides a battery monomer, a battery and electric equipment. The battery cell includes a housing and an electrode assembly. The shell comprises a first wall part, and the first wall part is provided with N pressure relief mechanisms arranged in the first direction. The electrode assembly is accommodated in the shell, the electrode assembly comprises a main body part and a tab, the main body part comprises a plurality of sub-regions, the tab is arranged at at least one end of the main body part along a first direction, 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 is greater than or equal to 400mm, and N is greater than or equal to 2. The projection of each pressure relief mechanism is correspondingly located in one sub-area in the thickness direction of the first wall part. And each pressure relief mechanism can discharge the 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 single battery can be effectively improved, and the reliability of the single battery is further improved.

Description

[0001] Cross-references to related applications

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

[0003] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery, and an electrical device. Background Technology

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

[0005] In battery technology, pressure relief mechanisms can be incorporated into individual battery cells to release pressure in the event of thermal runaway. However, for typical battery cells, pressure relief can still be delayed, resulting in relatively poor reliability. Therefore, improving the reliability of individual battery cells is a critical technical challenge that urgently needs to be addressed in battery technology. Summary of the Invention

[0006] This application provides a battery cell, a battery, and an electrical device, which can effectively improve the reliability of the battery cell.

[0007] In a first aspect, embodiments of this application provide a battery cell, including a casing and an electrode assembly; the casing includes 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 housed within the casing, and the electrode assembly includes a main body portion and a tab, at least one end of the main body portion is provided with a tab, the main body portion includes multiple sub-regions, the multiple sub-regions are continuously arranged along the first direction, the length of the main body portion is L, the length of the sub-regions is L1, L=L1×N, L≥400mm, N≥2; wherein, along the thickness direction of the first wall portion, the projection of each pressure relief mechanism is located in a corresponding sub-region, and the thickness direction of the first wall portion intersects with the first direction.

[0008] In the above technical solution, the projection of each pressure relief mechanism along the thickness direction of the first wall corresponds to a sub-region, so that 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 in the corresponding sub-region. If thermal runaway occurs in any sub-region, the emission medium generated by 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.

[0009] In some embodiments, the first wall supports the main body in the direction of gravity. This allows emissions from inside the casing to drain from the bottom of the casing. Since the first wall supports the main body within the casing, it is pressed down by the main body, making the area inside the casing near the first wall more prone to blockage and suffocation, hindering the discharge of the emission medium. However, because the first wall is equipped with multiple pressure relief mechanisms, it facilitates the discharge of the emission medium located near the first wall inside the casing, improving the reliability of the battery cell.

[0010] In some embodiments, the housing further includes a second wall portion. Along the thickness direction of the first wall portion, the first wall portion and the second wall portion are disposed opposite each other, and a channel gap is formed between the second wall portion and the main body portion. The channel gap is configured to connect the interior of the housing to the spaces located at both ends of the main body portion along a first direction. The channel gap connects the interior of the housing to the spaces 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 discharge medium accumulated near one end of the main body portion can be discharged through the pressure relief mechanism corresponding to that sub-region, or it can flow through the channel gap to the other end of the main body portion and be discharged through the pressure relief mechanism corresponding to the sub-region at the other end of the main body portion. This allows the discharge medium inside the battery cell to be discharged quickly, thereby improving the timeliness of pressure relief for the battery cell.

[0011] In some embodiments, the housing further includes a third wall portion and a fourth wall portion, which are disposed opposite to each other along a second direction. A first wall portion connects the third wall portion and the fourth wall portion, and the plane formed by the intersection of the thickness direction of the first wall portion and the first direction intersects the second direction. The thickness of both the third and fourth wall portions is less than the thickness of the first wall portion. This increases the thickness of the first wall portion, improves its resistance to deformation, reduces the risk of excessive deformation of the first wall portion due to battery cell expansion, thereby reducing the impact of first wall portion deformation on the pressure relief mechanism, reducing the risk of premature pressure relief mechanism activation, and improving the service life of the pressure relief mechanism.

[0012] 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 portion, the first wall portion has a first outer surface facing away from the main body portion, and the area of ​​the first outer surface is S2, where 0.05 ≤ S1 / S2 ≤ 0.55. S1 / S2 ≥ 0.05 results in a larger total pressure relief area of ​​the N pressure relief mechanisms, which is beneficial to improving the pressure relief rate of the battery cell and the timeliness of pressure relief of the battery cell; S1 / S2 ≤ 0.55 is beneficial to improving the strength of the first wall portion.

[0013] In some embodiments, 0.15 ≤ S1 / S2 ≤ 0.35.

[0014] In some embodiments, the predetermined pressure relief areas of the N pressure relief mechanisms are equal. This ensures that the pressure relief capacity of all pressure relief mechanisms on the first wall is substantially the same, and reduces the molding difficulty of each pressure relief mechanism.

[0015] In some embodiments, the housing includes a first half-region and a second half-region. Along a first direction, the portion of the housing's mid-section to one end is the first half-region, and the portion of the housing's mid-section to the other end is the second half-region. Both the first and second half-regions are provided with pressure relief mechanisms. The first direction is perpendicular to the mid-section. In the event of thermal runaway of a battery cell, pressure can be relieved through the pressure relief mechanisms in both the first and second half-regions. This allows the discharge medium located in the first half-region within the housing to be discharged more quickly through the pressure relief mechanism in the first half-region, and the discharge medium located in the second half-region within the housing to be discharged more quickly through the pressure relief mechanism in the second half-region, improving the timeliness of pressure relief for the battery cell.

[0016] In some embodiments, the first wall portion is provided with only two pressure relief mechanisms, which are located in the first half-region and the second half-region, respectively. This avoids having too many pressure relief mechanisms on the first wall portion, thereby achieving rapid pressure relief of the battery cells while reducing the manufacturing cost of the battery cells and achieving better economic efficiency.

[0017] In some embodiments, the pressure relief mechanism is provided with grooves along a first direction. The length of the outer casing is L2, and the minimum distance between the 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 grooves of two adjacent pressure relief mechanisms is not too small, allowing each pressure relief mechanism to correspond to a larger area of ​​the main body, making full use of each pressure relief mechanism and improving the timeliness of pressure relief for the battery cell.

[0018] In some embodiments, L3 / L2 ≥ 1 / 4.

[0019] In some embodiments, L2 ≥ 500 mm; and / or, L3 ≥ 300 mm. L2 ≥ 500 mm ensures a larger outer casing dimension in the first direction, meeting the high-capacity requirements of individual battery cells. L3 ≥ 300 mm prevents the minimum distance between adjacent pressure relief mechanisms from becoming too small, allowing each pressure relief mechanism to correspond to a larger area of ​​the main body. The discharge medium from a larger area of ​​the main body can be discharged through the corresponding pressure relief mechanism, fully utilizing each pressure relief mechanism and improving the timeliness of pressure relief for individual battery cells.

[0020] In some embodiments, the length of the outer casing is L2 along the first direction. The pressure relief mechanism is provided with grooves, and the sum of the maximum spans of the grooves of the N pressure relief mechanisms along the first direction is D1, where 0.2 ≤ D1 / L2 ≤ 0.6. D1 / L2 ≥ 0.2 ensures that the sum of the maximum spans of the grooves of the multiple pressure relief mechanisms on the first wall is large, increasing the total pressure relief area of ​​the multiple pressure relief mechanisms on the first wall, which is beneficial for improving the pressure relief rate of the battery cell. D1 / L2 ≤ 0.6 ensures that the sum of the maximum spans of the grooves of the multiple pressure relief mechanisms on the first wall is not too large, which is beneficial for improving the strength of the first wall.

[0021] In some embodiments, the pressure relief mechanism is provided with grooves, and a weak portion is formed in the area where the grooves are formed. The weak portion is configured to crack to release the pressure inside the battery cell. Forming the weak portion in the corresponding area of ​​the pressure relief mechanism by providing grooves is a simple method. The weak portion is a more vulnerable area in the pressure relief mechanism, and it is more easily damaged in the event of thermal runaway of the battery cell, thus facilitating timely pressure relief.

[0022] In some embodiments, the groove opening faces the main body along the thickness direction of the first wall portion. This makes the weak portion less prone to tearing when the first wall portion deforms due to the expansion of the battery cells, improving the long-term reliability of the pressure relief mechanism.

[0023] In some embodiments, the pressure relief mechanism includes a pressure relief area configured to open when the weak point cracks. During pressure relief, the pressure relief area can open with the weak point as the boundary, increasing the pressure relief area of ​​the pressure relief mechanism.

[0024] In some embodiments, the scoring groove is a groove extending along a closed trajectory, and the scoring groove is arranged around the pressure relief area. During the pressure relief process, after the pressure relief mechanism splits along the scoring groove, the pressure relief area can detach from the first wall, increasing the pressure relief area and improving the pressure relief rate of the battery cell.

[0025] In some embodiments, the pressure relief mechanism is integrally formed with the first wall portion. This improves the reliability of the pressure relief mechanism, eliminates the need for a connection process between the pressure relief mechanism and the first wall portion, and reduces the production cost of the battery cell.

[0026] In some embodiments, the pressure relief mechanism is separately disposed from the first wall portion, the first wall portion having 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 separately and then assembled, which is easy to manufacture and highly efficient.

[0027] In some embodiments, the first wall portion is provided with a first groove, the first groove including a groove side surface and a first groove bottom surface, the groove side surface surrounding the first groove bottom surface, a pressure relief hole being disposed on the first groove bottom surface, and a pressure relief mechanism being disposed within the first groove and abutting against the first groove bottom surface; wherein, at least a portion of the groove side surface along the circumference of the first groove forms a gap with the pressure relief mechanism. When the first wall portion deforms due to the expansion of the battery cell, the gap between the pressure relief mechanism and the groove side surface can provide buffer space for the pressure relief mechanism, reducing the risk of deformation of the pressure relief mechanism caused by the groove side surface squeezing it, thereby reducing the risk of the pressure relief mechanism opening prematurely during normal use of the battery cell and improving the service life of the pressure relief mechanism.

[0028] In some embodiments, the side of the groove includes a first region with a gap to the pressure relief mechanism. The length of the first region is L4 along the circumference of the first groove, and the circumference of the side of the groove is L5, satisfying: 0.2 ≤ L4 / L5 ≤ 1. This creates a gap between the longer portion of the side of the groove in the circumferential direction and the pressure relief mechanism, reducing the range of pressure exerted on the pressure relief mechanism by the side of the groove when the first wall deforms, further reducing the risk of premature opening of the pressure relief mechanism during normal use of the battery cell.

[0029] In some embodiments, a gap is formed between the entire circumference of the groove side and the pressure relief mechanism. This ensures that a gap exists between the groove side 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 on the pressure relief mechanism when the first wall deforms, and further reducing the risk of the pressure relief mechanism opening prematurely during normal use of the battery cell.

[0030] In some embodiments, the pressure relief mechanism is welded to the bottom wall of the first groove to form a first weld mark. This fixes the pressure relief mechanism to the first wall and improves the connection strength between the pressure relief mechanism and the first wall.

[0031] In some embodiments, the projection of the first weld mark is entirely located on the pressure relief mechanism along the thickness direction of the first wall. This allows the pressure relief mechanism to be welded to the bottom wall of the first groove via through-welding, a simple welding method. The resulting first weld mark can penetrate the pressure relief mechanism and embed itself into the bottom wall of the first groove, improving the connection strength between the pressure relief mechanism and the first wall. Furthermore, because the projection of the first weld mark along the thickness direction of the first wall is located on the pressure relief mechanism, the first weld mark does not protrude from the edge of the pressure relief mechanism, and is not located within the gap between the pressure relief mechanism and the side of the groove. This reduces the risk of the side of the groove squeezing the pressure relief mechanism through the first weld mark when the first wall deforms.

[0032] In some embodiments, the pressure relief mechanism is located on the side of the pressure relief hole away from the main body, along the thickness direction of the first wall portion. This allows the pressure relief mechanism to be installed on the outer side of the first wall portion, making installation more convenient.

[0033] In some embodiments, the battery cell further includes a protective member located on the side of the pressure relief mechanism away from the main body along the thickness direction of the first wall portion, and the protective member covers the first groove. The protective member can protect the pressure relief mechanism and reduce the risk of external substances (impurities, electrolyte) entering the first groove and corroding the pressure relief mechanism.

[0034] In some embodiments, along the thickness direction of the first wall portion, the first wall portion has a first outer surface facing away from the main body portion, and a second groove is provided on the first outer surface. The first groove is disposed on the bottom surface of the second groove, and the protective member is at least partially accommodated in the second groove. In this way, the height of the protective member protruding from the first outer surface of the first wall portion can be reduced, thereby reducing the space occupied by the protective member on the exterior of the housing.

[0035] 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 portion. This allows the pressure relief mechanism to be installed inside the first wall portion, which in turn protects it and reduces the risk of damage to the first wall portion from external components.

[0036] In some embodiments, the battery cell further includes a protective member located on the side of the pressure relief hole opposite to the main body, along the thickness direction of the first wall portion, and covering the pressure relief hole. The protective member can protect the pressure relief mechanism, reducing the risk of external substances (impurities, electrolyte) entering the pressure relief hole and corroding the pressure relief mechanism.

[0037] In some embodiments, the housing includes a casing and end caps; the casing has an opening at at least one end along a first direction, and the casing includes a first wall portion; the end caps correspond one-to-one with the openings, and the end caps close the openings. When assembling a battery cell, the electrode assembly can be installed into the casing first, and then the opening of the casing can be closed by the end caps, making the assembly of the battery cell convenient and quick.

[0038] In some embodiments, openings are formed at both ends of the housing along a first direction. During battery cell assembly, electrode assemblies can enter the housing from either end, effectively improving the assembly efficiency of the battery cells.

[0039] In some embodiments, the housing is a one-piece molded structure. This increases the housing's strength, its resistance to damage, and its service life.

[0040] In some embodiments, the shell is formed by bending a sheet metal, with the two ends of the sheet metal connected to each other along the circumference of the opening. When forming the shell, it is only necessary to bend the sheet metal and connect the two ends of the sheet metal to each other; the forming method of the shell is simple and can effectively reduce the difficulty of forming the shell.

[0041] In some embodiments, the two ends are welded together to form a second weld mark. This results in a strong connection between the two ends, making the connection more robust.

[0042] In some embodiments, the housing further includes a second wall portion, which is disposed opposite to the first wall portion along the thickness direction of the first wall portion; wherein the second solder mark portion is located on the second wall portion. This arrangement, with the second solder mark portion and the pressure relief mechanism located on opposite walls of the housing, reduces the impact of welding at the two ends of the sheet metal on the pressure relief mechanism, thereby improving the reliability of the pressure relief mechanism.

[0043] In some embodiments, the casing is cuboid in shape, with a first direction parallel to the length direction of the casing. The casing structure is simple and easy to mold. When battery cells are applied to a battery, the cuboid shape of the battery cell casing can reduce the installation gap between battery cells, which is beneficial to improving the volumetric energy density of the battery.

[0044] Secondly, embodiments of this application provide a battery, including the battery cell provided in any one of the embodiments of the first aspect.

[0045] Thirdly, embodiments of this application provide an electrical device, including a battery cell provided in any one of the embodiments of the first aspect, wherein the battery cell is used to provide electrical energy to the electrical device. Attached Figure Description

[0046] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0048] Figure 2 Exploded views of batteries provided for some embodiments of this application;

[0049] Figure 3 Axonometric views of a single battery cell provided in some embodiments of this application;

[0050] Figure 4 for Figure 3The exploded view of the battery cell shown;

[0051] Figure 5 Cross-sectional views of a battery cell provided in some embodiments of this application;

[0052] Figure 6 for Figure 5 The shown is a cross-sectional view of the outer casing cut along the YZ plane;

[0053] Figure 7 for Figure 5 A view of the battery cell shown from direction A;

[0054] Figure 8 for Figure 6 A magnified view of a portion of the outer shell at point B is shown.

[0055] Figure 9 Partial view of the first wall portion provided for some embodiments of this application;

[0056] Figure 10 Partial view of the first wall portion provided for other embodiments of this application;

[0057] Figure 11 A partial view of the first wall portion provided for some embodiments of this application;

[0058] Figure 12 Exploded views of a battery cell provided in other embodiments of this application;

[0059] Figure 13 for Figure 12 A cross-sectional view of the battery cell shown;

[0060] Figure 14 for Figure 13 A magnified view of a portion of the battery cell C shown;

[0061] Figure 15 for Figure 14 The cross-sectional view of the first wall shown;

[0062] Figure 16 Assembly diagram of the pressure relief mechanism and the first wall portion provided in some embodiments of this application;

[0063] Figure 17 for Figure 16 The diagram shows the structure of the first wall portion;

[0064] Figure 18 Assembly diagram of the pressure relief mechanism and the first wall portion provided in other embodiments of this application;

[0065] Figure 19 Partial views of a battery cell provided for other embodiments of this application;

[0066] Figure 20 A partial view of a battery cell provided for some embodiments of this application;

[0067] Figure 21 Exploded views of the casing provided for some embodiments of this application;

[0068] Figure 22 Exploded views of the casing provided for other embodiments of this application;

[0069] Figure 23 for Figure 21 The diagram shows the structural schematic of the shell.

[0070] Figure 24 Schematic diagrams of the housing structure provided for other embodiments of this application;

[0071] Figure 25 for Figure 24 The shown is a cross-sectional view of the shell cut along the YZ plane;

[0072] Figure 26 for Figure 25 The diagram shows the unfolded shape of the shell.

[0073] Icons: 1-Outer shell; 11-Housing shell; 111-First wall; 1111-Pressure relief hole; 1112-First groove; 1112a-Groove side; 1112b-First groove bottom; 1112c-Groove bottom wall; 1112d-First region; 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 face; 1122-Second end; 1122a-Second end face; 113-Third wall; 114-Fourth wall; 115-Second solder mark; 12-End cap; 13-Channel gap; 14-First space; 15-Second space; 16-First half-region; 17- Second half-region; 2-Electrode assembly; 21-Main body; 211-Sub-region; 22-Electrode tab; 3-Pressure relief mechanism; 31-Groove; 311-First arc segment; 312-First straight segment; 313-Second straight segment; 314-Third straight segment; 315-Fourth straight segment; 316-Fifth straight 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 solder mark; 7-Protective component; 10-Battery cell; 20-Casing; 201-First part; 202-Second part; 100-Battery; 200-Controller; 300-Motor; 1000-Vehicle; W-Midsection; X-First direction; Y-Second direction; Z-Thickness direction of the first wall. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0075] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0076] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0077] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0078] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0079] In this application, "multiple" means two or more (including two).

[0080] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0081] 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-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0082] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0083] 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.

[0084] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0085] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be 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. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can 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.).

[0086] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional 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. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide 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, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0087] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal may also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0088] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0089] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors 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.).

[0090] 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.

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

[0092] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0093] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0094] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical and mechanical stability.

[0095] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0096] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0097] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0098] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0099] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0100] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0101] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0102] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0103] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0104] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0105] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0106] In some implementations, the electrode assembly is a stacked structure.

[0107] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0108] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0109] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0110] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0111] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0112] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0113] In some embodiments, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0114] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0115] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0116] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0117] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0118] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0119] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0120] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0121] The development of battery technology must take into account multiple design factors, such as energy density, cycle life, discharge capacity, charge-discharge rate and other performance parameters. In addition, the reliability of individual battery cells also needs to be considered.

[0122] In battery technology, pressure relief mechanisms can be incorporated into individual battery cells to improve their reliability. These mechanisms have a significant impact on battery reliability. For example, short circuits or overcharging can cause thermal runaway within the battery cell, leading to a sudden increase in pressure or temperature. In such cases, pressure relief mechanisms can release internal pressure and temperature, reducing the probability of the battery cell exploding or catching fire.

[0123] In a typical battery cell, the cell includes a casing and an electrode assembly housed within the casing. The electrode assembly comprises a main body and tabs, with tabs located at one or both ends of the main body along a predetermined direction. The casing has only one pressure relief mechanism located at one end along the predetermined direction. In the event of thermal runaway of the battery cell, this mechanism releases the internal medium from the casing to relieve internal pressure. In such a battery cell, when the length of the main body is greater than or equal to 400 mm, during thermal runaway, the released medium generated in the area of ​​the main body near the pressure relief mechanism can flow to it, but the released medium generated in the area of ​​the main body far from the pressure relief mechanism is difficult to reach it, potentially leading to delayed pressure relief and poor reliability of the battery cell.

[0124] In view of this, this application provides a battery cell with N pressure relief mechanisms arranged along a first direction on the first wall of the outer casing, where L≥400mm and N≥2, and the main body of the electrode assembly is divided into N sub-regions continuously arranged along the first direction, each sub-region having an equal length along the first direction, and the projection of each pressure relief mechanism corresponding to a sub-region along the thickness direction of the first wall.

[0125] In such a battery cell, when the length of the main body is greater than or equal to 400mm, each sub-region can correspond to a pressure relief mechanism on the outer casing. Each pressure relief mechanism can discharge the emission medium generated by thermal runaway in the corresponding sub-region. If thermal runaway occurs in any sub-region, the emission medium generated by 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.

[0126] The battery cells described in the embodiments of this application are applicable to batteries and electrical devices that use battery cells.

[0127] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical equipment.

[0128] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0129] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. A battery 100 is disposed inside the vehicle 1000, and the battery 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000.

[0130] The vehicle 1000 may also 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, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0131] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0132] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery 100 provided in some embodiments of this application. The battery 100 includes a battery cell 10 and a housing 20, wherein the battery cell 10 is housed within the housing 20.

[0133] The housing 20 is a component that houses the battery cell 10, providing a space for the battery cell 10. The housing 20 can adopt various structures. In some embodiments, the housing 20 may include a first portion 201 and a second portion 202, which overlap each other to define a space for accommodating the battery cell 10. The first portion 201 and the second portion 202 can have various shapes, such as cuboid or cylindrical. The first portion 201 can be a hollow structure open on one side, and the second portion 202 can also be a hollow structure open on one side, with the open side of the second portion 202 overlapping the open side of the first portion 201, thus forming a housing 20 with a accommodating space. Alternatively, the first portion 201 can be a hollow structure open on one side, and the second portion 202 can be a plate-like structure, with the second portion 202 overlapping the open side of the first portion 201, thus forming a housing 20 with a accommodating space. The first part 201 and the second part 202 can be sealed by a sealing element, which can be a sealing ring, sealant, etc.

[0134] In battery 100, there can be one or more battery cells 10. If there are multiple battery cells 10, they can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 10 are connected in both series and parallel. Alternatively, multiple battery cells 10 can be first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed manner to form a whole, which is then housed within the housing 20. Another option is that all battery cells 10 can be directly connected in series, parallel, or in a mixed manner, and then the whole consisting of all battery cells 10 is housed within the housing 20.

[0135] In some embodiments, the battery 100 may further include a busbar component, through which multiple battery cells 10 can be electrically connected to each other to achieve series, parallel, or mixed connection of multiple battery cells 10. The busbar component may be a metallic conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0136] Please refer to Figure 3 and Figure 4 , Figure 3 Axonometric view of a battery cell 10 provided in some embodiments of this application; Figure 4 for Figure 3 The exploded view of the battery cell 10 is shown. The battery cell 10 may include a housing 1, an electrode assembly 2, and a pressure relief mechanism 3.

[0137] The housing 1 is a component for housing the electrode assembly 2 and electrolyte, etc. As an example, the housing 1 may include a housing 11 and an end cap 12.

[0138] The shell 11 can be a hollow structure with an opening at one end, or it can be a hollow structure with openings at both opposite ends. The shell 11 can be in various shapes, such as cylindrical or prismatic. The shell 11 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, or plastic.

[0139] End cap 12 is a component that closes the opening of housing 11 to isolate the internal environment of battery cell 10 from the external environment. End cap 12 and housing 11 together define a receiving space for accommodating electrode assembly 2, electrolyte, and other components. The shape of end cap 12 can be adapted to the shape of housing 1. For example, if housing 11 is a cuboid structure, end cap 12 can be a rectangular plate structure adapted to housing 1; or if housing 11 is a cylindrical structure, end cap 12 can be a circular plate structure adapted to housing 11. End cap 12 can also be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, or plastic. The materials of end cap 12 and housing 11 can be the same or different.

[0140] In an embodiment where the housing 11 has an opening at one end, one end cap 12 may be provided accordingly. In an embodiment where the housing 11 has openings at both opposite ends, two end caps 12 may be provided accordingly. The two end caps 12 respectively close the two openings of the housing 11, and the two end caps 12 and the housing 11 together define the receiving space.

[0141] The pressure relief mechanism 3 is a component for releasing the pressure inside the battery cell 10. When the internal pressure of the battery cell 10 reaches a threshold, the pressure relief mechanism 3 discharges the internal medium of the battery cell 10 to achieve the purpose of pressure relief. The discharge medium includes, but is not limited to: electrolyte, dissolved or broken positive and negative electrode plates, fragments of separators, gases generated during the reaction, flames, etc. The pressure relief mechanism 3 can be installed in the housing 11 or in the end cap 12.

[0142] In some embodiments, the battery cell 10 may further include electrode terminals 4, which are disposed on the housing 1. The electrode terminals 4 are used for electrical connection with the tabs 22 of the electrode assembly 2 to input or output electrical energy from the battery cell 10. The electrode terminals 4 may be disposed on the housing 11 of the housing 1 or on the end cap 12 of the housing 1. The electrode terminals 4 and the tabs 22 may be directly connected, for example, by direct welding. Alternatively, the electrode terminals 4 and the tabs 22 may be indirectly connected, for example, through a current collector.

[0143] As an example, such as Figure 4As shown, the housing 11 is a hollow structure with openings at both opposite ends. Both opposite ends of the housing 11 are provided with end caps 12, and both end caps 12 at both ends of the housing 11 are provided with electrode terminals 4. Both opposite ends of the electrode assembly 2 are provided with tabs 22. The tab 22 at one end of the electrode assembly 2 is the positive tab, and the tab 22 at the other end of the electrode assembly 2 is the negative tab. The electrode terminal 4 on one end cap 12 is electrically connected to the positive tab, and the electrode terminal 4 on the other end cap 12 is electrically connected to the negative tab.

[0144] Please refer to Figure 5 , Figure 5 This is a cross-sectional view of a battery cell 10 provided in some embodiments of this application. Embodiments of this application provide a battery cell 10, which includes a housing 1 and an electrode assembly 2. The housing 1 includes a first wall portion 111, on which N pressure relief mechanisms 3 are arranged along a first direction X. The electrode assembly 2 is housed within the housing 1 and includes a main body portion 21 and tabs 22. At least one end of the main body portion 21 is provided with a tab 22. The main body portion 21 includes multiple sub-regions 211, which are continuously arranged along the first direction X. The length of the main body portion 21 is L, and the length of each sub-region 211 is 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 corresponds to a sub-region 211, and the thickness direction Z of the first wall portion intersects with the first direction X.

[0145] The outer shell 1 can be cylindrical, prismatic, etc., and the prismatic shape can be triangular, square, pentagonal, hexagonal, etc. The square prismatic shape can include cuboid, cube, etc. In the embodiment where the outer shell 1 is cylindrical, the first direction X can be parallel to the axial direction of the outer shell 1; in the embodiment where the outer shell 1 is cuboid, the first direction X can be parallel to the length direction of the outer shell 1.

[0146] The first wall portion 111 can be an end cap 12 of the outer casing 1, and it is understood that the end cap 12 is provided with a pressure relief mechanism 3; the first wall portion 111 can also be at least one wall portion of the housing 11 in the outer casing 1, and it is understood that the housing 1 is provided with a pressure relief mechanism 3. The pressure relief mechanism 3 on the first wall portion 111 can be two, three, four, five, six or more, so N can be 2, 3, 4, 5, 6, etc.

[0147] The pressure relief mechanism 3 is a component that releases pressure inside the battery cell 10. When the internal pressure of the battery cell 10 reaches a threshold, the pressure relief mechanism 3 discharges the internal medium of the battery cell 10 to achieve pressure relief. The discharge medium includes, but is not limited to: electrolyte, dissolved or broken positive and negative electrode plates, fragments of the separator, gases generated during the reaction, flames, etc. The pressure relief mechanism 3 and the first wall portion 111 can be integrally formed or separate components.

[0148] The main body 21 has two opposite ends along a preset direction. A tab 22 may be provided at one end of the main body 21, or tabs 22 may be provided at both opposite ends of the main body 21. The preset direction may be parallel to or intersect with the first direction X; for example, the preset direction may be perpendicular to the first direction X. As an example, the preset direction is parallel to the first direction X, meaning that at least one end of the main body 21 along the first direction X has a tab 22. Figure 5 In the illustrated embodiment, both ends of the main body 21 in the first direction X are provided with tabs 22, one end of which is a positive tab and the other end of which is a negative tab. Both ends of the outer casing 1 are provided with electrode terminals 4, one end of which is electrically connected to the tab 22 at one end of the main body 21, and the other end of which is electrically connected to the tab 22 at the other end of the main body 21.

[0149] The electrode assembly 2 may include a positive electrode, a negative electrode, and a separator. The electrode assembly 2 can be a wound structure formed by winding the positive electrode, separator, and negative electrode, or a stacked structure formed by arranging the positive electrode, separator, and negative electrode in layers. The main body 21 may be the portion of the electrode assembly 2 corresponding to the area of ​​the electrode coated with the active material layer. The positive electrode tab may be the portion of the positive electrode that is not coated with the positive active material layer, and the negative electrode tab may be the portion of the negative electrode that is not coated with the negative active material layer.

[0150] L = L1 × N means that, along the first direction X, the main body 21 is evenly divided into multiple sub-regions 211. The number of sub-regions 211 is equal to the number of pressure relief mechanisms 3 arranged along the first direction X on the first wall 111, 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.

[0151] L can be any one of the following values: 400mm, 500mm, 600mm, 700mm, 800mm, 900mm, 1000mm, etc., or a range between any two.

[0152] Along the thickness direction Z of the first wall, the projection of each pressure relief mechanism 3 is located in a sub-region 211. In other words, when viewed along the thickness direction Z of the first wall, each pressure relief mechanism 3 is obscured by a corresponding sub-region 211.

[0153] The thickness direction Z of the first wall portion can be perpendicular to the first direction X, or it can be set at an acute or obtuse angle. As an example, in Figure 5 In the first wall portion, the thickness direction Z is perpendicular to the first direction X.

[0154] For a typical battery cell 10, a length of 400mm or more for the main body 21 can meet the large capacity requirements of the battery cell 10, but the pressure relief capability is poor, and the pressure relief is prone to being untimely. In this embodiment, the projection of each pressure relief mechanism 3 along the thickness direction Z of the first wall is located in a sub-region 211, so that each sub-region 211 can correspond to a pressure relief mechanism 3 on the outer casing 1. Each pressure relief mechanism 3 can discharge the emission medium generated by thermal runaway of the corresponding sub-region 211. If thermal runaway occurs in any sub-region 211 of the main body 21, the emission medium generated by thermal runaway can be quickly discharged through the corresponding pressure relief mechanism 3, which can effectively improve the timeliness of pressure relief of the battery cell 10, thereby improving the reliability of the battery cell 10.

[0155] In some embodiments, the first wall portion 111 supports the main body portion 21 along the direction of gravity.

[0156] 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 outer shell 1 that supports the main body portion 21 along the direction of gravity, and 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, and the first wall portion 111 supports 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.

[0157] In this embodiment, the first wall portion 111 supports the main body portion 21 along the direction of gravity, and the emissions inside the outer casing 1 can be discharged from the bottom of the outer casing 1. Since the first wall portion 111 is the wall portion supporting the main body portion 21 in the outer casing 1, the first wall portion 111 is pressed down by the main body portion 21, and the area inside the outer casing 1 near the first wall portion 111 is more prone to blockage and air stagnation, which is not conducive to the discharge of the emission medium. However, since the first wall portion 111 is provided with multiple pressure relief mechanisms 3, it is more conducive to the discharge of the emission medium inside the outer casing 1 near the first wall portion 111, thereby improving the reliability of the battery cell 10.

[0158] In some embodiments, please continue to refer to Figure 5 The outer casing 1 also includes a second wall portion 112. Along the thickness direction Z of the first wall portion, the first wall portion 111 and the second wall portion 112 are disposed opposite to each other. 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 communicate with the interior of the outer casing 1 in the space located at both ends of the main body portion 21 along the first direction X.

[0159] The first wall portion 111 and the second wall portion 112 are two opposing wall portions of the outer shell 1. The thickness of the first wall portion 111 and the second wall portion 112 may be equal or unequal.

[0160] A channel gap 13 is formed between the second wall portion 112 and the main body portion 21. The spaces located at both ends of the main body portion 21 along the first direction X inside the outer casing 1 are a first space 14 and a second space 15, respectively. The channel gap 13 connects the first space 14 and the second space 15. In the event of thermal runaway of the battery cell 10, the discharge medium of one of the first space 14 and the second space 15 can flow to the other through the channel gap 13.

[0161] In this embodiment, the channel gap 13 can connect the spaces inside the outer casing 1 located 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, or it can 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. This allows the discharge medium inside the battery cell 10 to be discharged quickly, thereby improving the timeliness of pressure relief of the battery cell 10.

[0162] In some embodiments, please refer to Figure 6 , Figure 6 for Figure 5 The diagram shows a cross-sectional view of the outer casing 1 taken along the YZ plane. The casing 1 also includes a third wall portion 113 and a fourth wall portion 114, which are disposed opposite each other along the second direction Y. A first wall portion 111 connects the third wall portion 113 and the fourth wall portion 114. The 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 both the third wall portion 113 and the fourth wall portion 114 is less than the thickness of the first wall portion 111.

[0163] The plane formed by the intersection of the thickness direction Z of the first wall and the first direction X intersects the second direction Y, such that the thickness direction Z of the first wall, the first direction X, and the second direction Y are not coplanar.

[0164] The thickness of the first wall portion 111 and the thickness of the second wall portion 112 can be equal; the thickness of the first wall portion 111 and the thickness of the second wall portion 112 can also be unequal, for example, the thickness of the first wall portion 111 is greater than the thickness of the second wall portion 112.

[0165] 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.

[0166] In this embodiment, 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. This can increase the thickness of the first wall portion 111, improve its resistance to deformation, reduce the risk of excessive deformation of the first wall portion 111 due to the 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 prematurely to relieve pressure, and improving the service life of the pressure relief mechanism 3.

[0167] In some embodiments, the sum of the predetermined pressure relief areas of the 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, and the area of ​​the first outer surface 1113 is S2, where 0.05≤S1 / S2≤0.55.

[0168] The predetermined pressure relief areas of N pressure relief mechanisms 3 can be equal, or at least two pressure relief mechanisms 3 can have unequal predetermined pressure relief areas. The predetermined pressure relief area of ​​the pressure relief mechanism 3 is the maximum area that the pressure relief mechanism 3 is expected to open.

[0169] Taking the first wall portion 111 as an example where 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 ​​another 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.

[0170] 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 rectangular. By measuring the length and width of the first outer surface 1113 of the first wall portion 111, and multiplying the length and width of the first outer surface 1113, the area of ​​the first outer surface 1113 of the first wall portion 111 can be calculated. In the 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 can be connected by a rounded corner surface, and the first outer surface 1113 of the first wall portion 111 and the outer surface of the fourth wall portion 114 can be connected by another rounded corner surface.

[0171] In this embodiment, S1 / S2 can be any one of the following point values ​​or a range of values ​​between any two: 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.

[0172] In this embodiment, S1 / S2≥0.05, which makes the total pressure relief area of ​​the N pressure relief mechanisms 3 larger, which is beneficial to improving the pressure relief rate of the battery cell 10 and the timeliness of pressure relief of the battery cell 10; S1 / S2≤0.55, which is beneficial to improving the strength of the first wall portion 111.

[0173] In some embodiments, 0.15 ≤ S1 / S2 ≤ 0.35.

[0174] In this embodiment, S1 / S2 can be any one of the following point values ​​or a range of values ​​between any two: 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.

[0175] In some embodiments, the predetermined pressure relief areas of the N pressure relief mechanisms 3 are equal.

[0176] Taking the first wall portion 111 as an example, which is 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.

[0177] In this embodiment, the predetermined pressure relief areas of the N pressure relief mechanisms 3 are equal, so that the pressure relief capacity of all pressure relief mechanisms 3 on the first wall 111 is basically the same, and the molding difficulty of each pressure relief mechanism 3 can be reduced.

[0178] In some embodiments, please refer to Figure 7 , Figure 7 for Figure 5 The battery cell 10 is shown in view A. The housing 1 includes a first half-section 16 and a second half-section 17. Along the first direction X, the portion from the mid-section W of the housing 1 to one end of the housing 1 is the first half-section 16, and the portion from the mid-section W of the housing 1 to the other end of the housing 1 is the second half-section 17. Both the first half-section 16 and the second half-section 17 are provided with at least one pressure relief mechanism 3. The first direction X is perpendicular to the mid-section W.

[0179] Along the first direction X, the outer casing 1 has two opposing end faces. The distance from the mid-section W of the outer casing 1 to the two end faces is equal. The portion of the outer casing 1 from one end face to the mid-section W is the first half-region 16, and the portion of the outer casing 1 from the other end face to the mid-section W is the second half-region 17. In an embodiment where the casing 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 outside of the outer casing 1 can be one end face of the outer casing 1, and the surface of the wall portion of the casing 11 opposite to the end cap 12 facing the outside of the outer casing 1 can be the other end face of the outer casing 1. In an embodiment where the casing 11 is a hollow structure with openings at both opposite ends along the first direction X, the surface of one end cap 12 facing the outside of the outer casing 1 can be one end face of the outer casing 1, and the surface of the other end cap 12 facing the outside of the outer casing 1 can be the other end face of the outer casing 1.

[0180] The first half-zone 16 can be equipped with one or more pressure relief mechanisms 3; the second half-zone 17 can be equipped with one or more pressure relief mechanisms 3.

[0181] When the battery cell 10 experiences thermal runaway, pressure can be released through the pressure relief mechanism 3 of the first half-zone 16 and the pressure relief mechanism 3 of the second half-zone 17. This allows the discharge medium located in the first half-zone 16 inside the casing 1 to be discharged more quickly through the pressure relief mechanism 3 of the first half-zone 16, and the discharge medium located in the second half-zone 17 inside the casing 1 to be discharged more quickly through the pressure relief mechanism 3 of the second half-zone 17, thereby improving the timeliness of pressure relief for the battery cell 10.

[0182] In some embodiments, the first wall portion 111 is provided with only two pressure relief mechanisms 3, which are located in the first half-zone 16 and the second half-zone 17, respectively.

[0183] It is understandable that, of the two pressure relief mechanisms 3, one pressure relief mechanism 3 is located in the portion of the first wall portion 111 located in the first half-zone 16, and the other pressure relief mechanism 3 is located in the portion of the first wall portion 111 located in the second half-zone 17.

[0184] In this embodiment, the first wall portion 111 is provided with only two pressure relief mechanisms 3, so that there are not too many pressure relief mechanisms 3 on the first wall portion 111. While realizing rapid pressure relief of the battery cell 10, the manufacturing cost of the battery cell 10 is reduced, which has better economic efficiency.

[0185] In some embodiments, please continue to refer to Figure 7 The pressure relief mechanism 3 is provided with a groove 31. Along the first direction X, the length of the outer shell 1 is L2. The minimum distance between the grooves 31 of two adjacent pressure relief mechanisms 3 is L3, L2>L, and L3 / L2≥1 / 6.

[0186] Along the first direction X, the maximum distance between the end faces of the two ends of the outer casing 1 is the length of the outer casing 1. If the two end faces of the outer casing 1 are flat, the length of the outer casing 1 along the first direction X is measured with the two end faces as a reference; if one or two end faces of the outer casing 1 have a protrusion or a recess, the length of the outer casing 1 along the first direction X is measured with the flat area of ​​that end face as a reference. The distance between the two closest positions of the grooves 31 of two adjacent pressure relief mechanisms 3 is the minimum distance between the grooves 31 of the two adjacent pressure relief mechanisms 3.

[0187] L3 / L2 can be any one of the point values ​​of 1 / 6, 1 / 5, 1 / 4, 1 / 3, 1 / 2, 2 / 3, or any range between the two.

[0188] In this embodiment, L3 / L2≥1 / 6, so that the minimum distance between the 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, making full use of each pressure relief mechanism 3 and improving the timeliness of pressure relief of the battery cell 10.

[0189] In some embodiments, L3 / L2 ≥ 1 / 4.

[0190] In this embodiment, L3 / L2 can be any one of the point values ​​of 1 / 4, 1 / 3, 5 / 12, 1 / 2, 7 / 12, 2 / 3, or any range between two of them.

[0191] 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 end of the housing 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 portion 21 inside the housing 11.

[0192] In some embodiments, L2 ≥ 500 mm; and / or, L3 ≥ 300 mm.

[0193] L2 can be any one of the following values: 500mm, 550mm, 600mm, 650mm, 750mm, 800mm, etc., or a range between any two. L3 can be any one of the following values: 300mm, 330mm, 350mm, 380mm, 400mm, 430mm, 450mm, etc., or a range between any two.

[0194] L2≥500mm, the outer casing 1 has a larger size in the first direction X, which can meet the large capacity requirements of the battery cell 10. L3≥300mm, so that the minimum distance between 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. The discharge medium of the larger area of ​​the main body 21 can be discharged through the corresponding pressure relief mechanism 3, making full use of each pressure relief mechanism 3 and improving the timeliness of pressure relief of the battery cell 10.

[0195] In some embodiments, please continue to refer to Figure 7 Along the first direction X, the length of the outer shell 1 is L2. The pressure relief mechanism 3 is provided with a groove 31. The sum of the maximum span of the grooves 31 of the N pressure relief mechanisms 3 along the first direction X is D1, and 0.2≤D1 / L2≤0.6.

[0196] The maximum span of the groove 31 along the first direction X is the distance between the two farthest positions of the groove 31 along the first direction X. The maximum span of the grooves 31 of the N pressure relief mechanisms 3 on the first wall portion 111 along the first direction X can be equal, or the maximum span of the grooves 31 of at least two pressure relief mechanisms 3 on the first wall portion 111 along the first direction X can be unequal. The groove 31 can be a groove extending along a closed trajectory, which can be circular, rectangular, etc.; the groove 31 can also be a groove along a non-closed trajectory, which can be straight, arc-shaped, U-shaped, H-shaped, V-shaped, L-shaped, X-shaped, Y-shaped, etc. The groove 31 can be located inside the pressure relief mechanism 3 (the side of the pressure relief mechanism 3 facing the main body portion 21 along the thickness direction Z of the first wall portion) or outside the pressure relief mechanism 3 (the side of the pressure relief mechanism 3 away from the main body portion 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, some of the grooves 31 of the pressure relief mechanism 3 may be located on the inner side of the pressure relief mechanism 3, and other parts of the grooves 31 of the pressure relief mechanism 3 may be located on the outer side of the pressure relief mechanism 3. Alternatively, all the grooves 31 of the pressure relief mechanism 3 may be located on the inner side of the pressure relief mechanism 3, or all the grooves 31 of the pressure relief mechanism 3 may be located on the outer side of the pressure relief mechanism 3.

[0197] Taking the first wall portion 111 as an example where only two pressure relief mechanisms 3 are provided, the maximum span of the groove 31 of one pressure relief mechanism 3 along the first direction X is D2, and the maximum span of the groove 31 of the other pressure relief mechanism 3 along the first direction X is D3, where D1 = D2 + D3.

[0198] In this embodiment, D1 / L2 can be any one of the following point values ​​or a range between any two: 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.

[0199] In this embodiment, D1 / L2 ≥ 0.2 ensures that the sum of the maximum spans of the grooves 31 of the plurality of pressure relief mechanisms 3 on the first wall portion 111 along the first direction X is large, which increases the total pressure relief area of ​​the plurality of pressure relief mechanisms 3 on the first wall portion 111 and is beneficial to improving the pressure relief rate of the battery cell 10. D1 / L2 ≤ 0.6 ensures that the sum of the maximum spans of the grooves 31 of the plurality of pressure relief mechanisms 3 on the first wall portion 111 along the first direction X is not too large, which is beneficial to improving the strength of the first wall portion 111.

[0200] In some embodiments, please refer to Figure 8 , Figure 8 for Figure 6 The enlarged view of the outer casing 1 is shown. The pressure relief mechanism 3 is provided with a groove 31, and a weak part 32 is formed in the area where the groove 31 is provided. The weak part 32 is configured to crack to release the pressure inside the battery cell 10.

[0201] The weakest part 32 is the section of the pressure relief mechanism 3 that is weaker than other areas. After the pressure relief mechanism 3 is provided with a groove 31, the remaining part of the pressure relief mechanism 3 corresponding to the groove 31 is the weakest part 32, which can be the bottom wall of the groove 31. In the event of thermal runaway of the battery cell 10, the pressure relief mechanism 3 can crack at the weakest part 32 to release the pressure inside the battery cell 10.

[0202] In this embodiment, a weak portion 32 is formed in the corresponding area of ​​the pressure relief mechanism 3 by setting a groove 31, which is a simple way to form the weak portion 32. The weak portion 32 is a weaker area in the pressure relief mechanism 3, and it is more likely to be damaged when the battery cell 10 experiences thermal runaway, so as to relieve pressure in time.

[0203] In some embodiments, please continue to refer to Figure 8 Along the thickness direction Z of the first wall portion, the groove opening of the groove 31 faces away from the main body portion 21. Figure 8 (Not shown).

[0204] As an example, the groove 31 is provided on the outside of the pressure relief mechanism 3, so that the opening of the groove 31 faces the main body 21.

[0205] In this embodiment, the groove opening of the scoring groove 31 is away from the main body 21. If the pressure relief mechanism 3 is integrally formed with the first wall 111, it is convenient to process the scoring groove 31 on the first wall 111. If the pressure relief mechanism 3 and the first wall 111 are separately set, it is convenient to install the pressure relief mechanism 3 on the first wall 111.

[0206] In other embodiments, the groove opening of the groove 31 faces the main body 21 along the thickness direction Z of the first wall portion.

[0207] As an example, the groove 31 is provided inside the pressure relief mechanism 3 so that the opening of the groove 31 faces the main body 21.

[0208] In this embodiment, the groove 31 faces the main body 21, so that the weak part 32 is not easily torn when the first wall 111 deforms due to the expansion of the battery cell 10, thereby improving the long-term reliability of the pressure relief mechanism 3.

[0209] In some embodiments, the pressure relief mechanism 3 includes a pressure relief zone 33, which is configured to open when the weak portion 32 cracks.

[0210] The pressure relief zone 33 is the portion of the pressure relief mechanism 3 that can be opened after it splits along the weak portion 32. The pressure relief zone 33 can be provided along the edge of the weak portion 32. During pressure relief, the pressure relief zone 33 can be opened by flipping or detaching. The area of ​​the pressure relief zone 33 is the predetermined pressure relief area of ​​the pressure relief mechanism 3.

[0211] In this embodiment, the groove 31 can be a groove extending along a closed trajectory; the groove 31 can also be a groove extending along a non-closed trajectory, which can be an arc, U, H, V, L, Y, X, etc.

[0212] In this embodiment, the weak part 32 defines the pressure relief area 33. When the pressure is released, the pressure relief area 33 can open with the weak part 32 as the boundary, thereby increasing the pressure relief area of ​​the pressure relief mechanism 3.

[0213] In some embodiments, please refer to Figure 9 , Figure 9 This is a partial view of the first wall portion 111 provided for some embodiments of this application. The groove 31 is a groove extending along a closed trajectory and is disposed around the pressure relief area 33.

[0214] It is understandable that the groove 31 is an annular groove surrounding the pressure relief area 33.

[0215] As an example, such as Figure 9 As shown, the 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 in sequence. The central angle of both first arc segments 311 is 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 / 4. Where 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 groove of the scoring groove 31 is located.

[0216] In this embodiment, the groove 31 is a groove extending along a closed trajectory. During the pressure relief process, after the pressure relief mechanism 3 splits along the groove 31, the pressure relief area 33 can be separated from the first wall portion 111, which increases the pressure relief area and improves the pressure relief rate of the battery cell 10.

[0217] In some embodiments, please refer to Figure 10 and Figure 11 , Figure 10 A partial view of the first wall portion 111 provided for other embodiments of this application; Figure 11 A partial view of the first wall portion 111 provided for some embodiments of this application. The groove 31 is a groove extending along a non-closed trajectory.

[0218] As an example, such as Figure 10 As shown, the groove 31 is an H-shaped groove, comprising a second straight segment 313 and two third straight segments 314. The two third straight segments 314 are arranged in parallel. One end of the second straight segment 313 is connected to the midpoint of one of the third straight segments 314, and the other end of the second straight segment 313 is connected to the midpoint of the other third straight 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. Where 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 the third straight line segment 314 and the side of the second straight line segment 313 facing that end. Both c and d can be measured on the surface where the groove of the scoring groove 31 is located.

[0219] As an example, such as Figure 11As shown, the groove 31 is a double Y-shaped groove, comprising a fourth straight segment 315 and a fifth straight segment 316. Two fifth straight segments 316 are connected to both ends of the fourth straight segment 315 at a non-zero included angle. Along the length 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 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 of the fourth straight segment 315, the line connecting the free ends of the two fifth straight segments 316 is the first connecting line 317; along the width of the fourth straight segment 315, the line connecting the free ends of the two fifth straight segments 316 is the second connecting 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. Where f is the length of the fourth straight line segment 315, g is the length of the first connecting line 317, e is the distance between the first connecting line 317 and the side of the fourth straight line segment 315 facing the first connecting line 317, k is the length of the second connecting line 318, and h is the distance between the connection position of the two fifth straight lines 316 located at the end of the fourth straight line segment 315 facing the second connecting line 318 and the second connecting line 318. f, g, e, k and h can all be measured on the surface where the groove of the scoring groove 31 is located.

[0220] In some embodiments, please continue to refer to Figure 6 and Figure 8 The pressure relief mechanism 3 is integrally formed with the first wall part 111.

[0221] In an embodiment where the pressure relief mechanism 3 is provided with a groove 31, the pressure relief mechanism 3 can be composed of a weak part 32 and a pressure relief area 33. The weak part 32, the pressure relief area 33 and the first wall part 111 are integrally formed, thus realizing that the pressure relief mechanism 3 and the first wall part 111 are integrally formed.

[0222] As an example, the outer casing 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. The thickness direction Z, the first direction X, and the second direction Y of the first wall portion are perpendicular to each other. The third wall portion 113 and the fourth wall portion 114 may be the wall portion with the largest area on the outer surface of the outer casing 1.

[0223] In this embodiment, the pressure relief mechanism 3 is integrally formed with the first wall portion 111, which makes the pressure relief mechanism 3 more reliable and eliminates the connection process between the pressure relief mechanism 3 and the first wall portion 111, thereby reducing the production cost of the battery cell 10.

[0224] In some embodiments, please refer to Figure 12 and Figure 13 , Figure 12 Exploded views of the battery cell 10 provided in other embodiments of this application; Figure 13 for Figure 12 The diagram shows a cross-sectional view of the battery cell 10. The pressure relief mechanism 3 is separately disposed 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 installed on the first wall portion 111 and covers the pressure relief hole 1111.

[0225] The pressure relief mechanism 3 and the outer casing 1 are two separate components, molded separately and then assembled together. The pressure relief mechanism 3 can be a component such as an explosion-proof plate, explosion-proof valve, or safety valve. The pressure relief mechanism 3 can be installed on the first wall 111 by means of bonding, welding, or other methods. When the battery cell 10 experiences thermal runaway, the pressure relief mechanism 3 opens at least part of the pressure relief port 1111, and the discharge medium inside the battery cell 10 is discharged through the pressure relief port 1111 to release the pressure inside the battery cell 10.

[0226] The pressure relief mechanism 3 covers the pressure relief hole 1111, blocking it. The projection of the hole wall of the pressure relief hole 1111 along the thickness direction Z of the first wall can be entirely located within 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 it can be 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. 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 internal space of the outer casing 1. In the event of thermal runaway of the battery cell 10, the pressure relief mechanism 3 is destroyed, and the pressure relief hole 1111 communicates with the internal space of the outer casing 1, allowing the discharge medium inside the outer casing 1 to 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 experiences thermal runaway, 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.

[0227] As an example, such as Figure 12 and Figure 13As shown, the pressure relief mechanism 3 is an explosion-proof plate, which is installed on the first wall portion 111. The explosion-proof plate is a plate with a strength of less than that of the first wall portion 111 in at least a portion of its area, and it covers the pressure relief hole 1111. When the battery cell 10 experiences thermal runaway, the explosion-proof plate 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.

[0228] In this embodiment, the pressure relief mechanism 3 is a component independent of the outer shell 1. The pressure relief mechanism 3 and the outer shell 1 can be manufactured separately and assembled, which is easy to manufacture and efficient.

[0229] In some embodiments, please refer to Figure 14 and Figure 15 , Figure 14 for Figure 13 A magnified view of a portion of battery cell 10 shown; Figure 15 for Figure 14 The diagram shows a cross-sectional view of the first wall portion 111. The first wall portion 111 has a first groove 1112, which includes a groove side surface 1112a and a first groove bottom surface 1112b. The groove side surface 1112a surrounds the first groove bottom surface 1112b. A pressure relief hole 1111 is located on the first groove bottom surface 1112b. A pressure relief mechanism 3 is disposed within the first groove 1112 and abuts against the first groove bottom surface 1112b. At least a portion of the groove side surface 1112a along the circumference of the first groove 1112 forms a gap 5 between it and the pressure relief mechanism 3.

[0230] The first groove 1112 can be formed in the first wall portion 111 by various methods, such as stamping, milling, and laser etching. The groove side surface 1112a is a closed structure extending circumferentially along the first groove 1112. Along the depth direction of the first groove 1112, the groove opening of the first groove 1112 is opposite to the bottom surface 1112b of the first groove, 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 bottom surface 1112b of the first groove can be polygonal; if the first groove 1112 is circular, the cross-section of the groove side surface 1112a is circular, and the bottom surface 1112b of the first groove can be circular. 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, which are connected end to end along the circumference of the first groove 1112. A side surface may be a surface parallel to the thickness direction Z of the first wall portion, or perpendicular to the bottom surface 1112b of the first groove; alternatively, it may be an obtuse angled surface with respect to the bottom surface 1112b of the first groove. Of course, a side surface can be a plane or an arc surface. If the side surface is an arc surface, it can be an arc surface with its centerline parallel to the thickness direction Z of the first wall portion, or it can be an arc surface with its centerline perpendicular to the thickness direction Z of the first wall portion.

[0231] The pressure relief mechanism 3 is disposed within the groove. The pressure relief mechanism 3 can be entirely located within the first groove 1112, or partially located within and partially located outside the first groove 1112. The pressure relief mechanism 3 can be connected to the first wall portion 111 in various ways, such as welding or bonding. The pressure relief mechanism 3 can directly contact the bottom surface 1112b of the first groove, allowing it to directly abut against the bottom surface 1112b; alternatively, it can indirectly abut against the bottom surface 1112b via an intermediate component. For example, the pressure relief mechanism 3 can be welded to the bottom wall 1112c of the first groove 1112, allowing it to directly contact the bottom surface 1112b; or, it can be bonded to the bottom wall 1112c of the first groove 1112 via an adhesive layer, allowing it to indirectly abut against the bottom surface 1112b.

[0232] The circumference of the first groove 1112 surrounds the depth direction of the first groove 1112, and the circumference of the opening of the first groove 1112 is the circumference of the first groove 1112. A gap 5 may be formed between a portion of the groove side surface 1112a along the circumference of the first groove 1112 and the pressure relief mechanism 3, or a gap 5 may be formed between the entire groove side surface 1112a along the circumference of the first groove 1112 and the pressure relief mechanism 3. The pressure relief mechanism 3 has an outer peripheral surface 34 facing the groove side surface 1112a, and the outer peripheral surface 34 is a closed structure extending circumferentially along the pressure relief mechanism 3. If a portion of the groove side surface 1112a along the circumference of the first groove 1112 forms a gap 5 with the outer peripheral surface 34 of the pressure relief mechanism 3, and another portion of the groove side surface 1112a along the circumference of the first groove 1112 does not form a gap 5 with the outer peripheral surface 34 of the pressure relief mechanism 3, then a gap 5 is formed between the groove side surface 1112a along the circumference of the first groove 1112 and the pressure relief mechanism 3. This gap 5 is a non-closed structure extending along the circumference of the first groove 1112. If the groove side surface 1112a along the entire circumference of the first groove 1112 forms a gap 5 with the outer peripheral surface 34 of the pressure relief mechanism 3, then a gap 5 is formed between the groove side surface 1112a along the entire circumference of the first groove 1112 and the pressure relief mechanism 3. This gap 5 is a closed structure extending along the circumference of the first groove 1112, that is, this gap 5 is an annular gap.

[0233] As an example, the pressure relief mechanism 3 is provided with a groove 31 to correspondingly form a weak part 32. Figure 14 and Figure 15 (Not shown).

[0234] When the first wall portion 111 deforms due to the expansion of the battery cell 10, the gap 5 between the pressure relief mechanism 3 and the side surface 1112a of the groove can provide a buffer space for the pressure relief mechanism 3, reducing the risk of the pressure relief mechanism 3 being deformed due to the side surface 1112a of the groove squeezing it. This reduces the risk of the pressure relief mechanism 3 opening prematurely during normal use of the battery cell 10 and improves the service life of the pressure relief mechanism 3.

[0235] In some embodiments, please refer to Figure 16 and Figure 17 , Figure 16 Assembly diagram of the pressure relief mechanism 3 and the first wall portion 111 provided in some embodiments of this application; Figure 17 for Figure 16 The diagram shows the structure of the first wall portion 111. 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 perimeter of the groove side surface 1112a is L5, satisfying: 0.2≤L4 / L5≤1.

[0236] The length of the first region 1112d is the total length of the portion of the groove side 1112a that forms a 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 1112a, the measurement can be taken along the edge of the groove side 1112a located at the groove opening of the first groove 1112.

[0237] L4 / L5 can be any point value from 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc., or a range of values ​​between any two.

[0238] As an example, the groove side 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 connected end to end to form a closed structure. Among them, the first side surface 1112e extends along the first direction X of the first wall portion 111, the second side surface 1112f is an arc surface, and a gap 5 is formed between the two first side surfaces 1112e and the pressure relief mechanism 3. Only a portion of each second side surface 1112f forms a gap 5 with the pressure relief mechanism 3. It is understandable that the two second side surfaces 1112f and the pressure relief mechanism 3 forming a gap 5 together, and the two first side surfaces 1112e together constitute the first region 1112d. Along the circumference of the first groove 1112, the total length of the two second side surfaces 1112f and the pressure relief mechanism 3 forming a gap 5 together, and the two first side surfaces 1112e together is the length of the first region 1112d. The total length of the two first side surfaces 1112e and the two second side surfaces 1112f together is the perimeter of the groove side surface 1112a.

[0239] In this embodiment, 0.2≤L4 / L5≤1, so that a gap 5 is formed between the longer portion of the groove side 1112a in the circumferential direction and the pressure relief mechanism 3, reducing the compression range of the groove side 1112a on the pressure relief mechanism 3 when the first wall 111 deforms, and further reducing the risk of the pressure relief mechanism 3 opening prematurely during the normal use of the battery cell 10.

[0240] In some embodiments, please refer to Figure 18 , Figure 18 This is an assembly diagram of the pressure relief mechanism 3 and the first wall portion 111 provided in other embodiments of this application. The groove side surface 1112a forms a gap 5 with the pressure relief mechanism 3 along the entire circumference of the first groove 1112.

[0241] 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 circumferentially along the first groove 1112. In this embodiment, the first region 1112d is the groove side surface 1112a, and L4 / L5 = 1.

[0242] In this embodiment, there is a gap 5 between 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, which further reduces the squeezing effect of the groove side 1112a on the pressure relief mechanism 3 when the first wall 111 deforms, and further reduces the risk of the pressure relief mechanism 3 opening prematurely during normal use of the battery cell 10.

[0243] In some embodiments, please refer to Figure 19 , Figure 19 This is a partial view of a battery cell 10 provided in some other embodiments of this application. The pressure relief mechanism 3 is welded to the bottom wall 1112c of the first groove 1112 to form a first solder mark 6.

[0244] The bottom wall 1112c of the first groove 1112 is a solid portion of the pressure relief mechanism 3 located below the bottom surface 1112b of the first groove along the depth direction of the first groove 1112, and has a thickness. The first weld mark 6 is a welding area formed between the pressure relief mechanism 3 and the bottom wall 1112c. The first weld mark 6 can be formed by fusing a part of the pressure relief mechanism 3 with a part of the bottom wall 1112c. The weld mark can be a ring structure extending circumferentially along the pressure relief mechanism 3, a multi-segment structure spaced apart circumferentially along the pressure relief mechanism 3, or a long strip structure extending along a straight trajectory.

[0245] In this embodiment, the pressure relief mechanism 3 is welded to the bottom wall 1112c of the first groove 1112, thereby fixing the pressure relief mechanism 3 to the first wall 111 and improving the connection strength between the pressure relief mechanism 3 and the first wall 111.

[0246] In some embodiments, along the thickness direction Z of the first wall portion, the projection of the first solder mark 6 is entirely located on the pressure relief mechanism 3.

[0247] Viewed along the thickness direction Z of the first wall portion, the entire solder mark is located within the area defined by the outer edge of the pressure relief mechanism 3, and there is no portion of the solder mark located outside the area defined by the outer edge of the pressure relief mechanism 3. The solder mark has a portion located within the pressure relief mechanism 3 and also a portion located within the bottom wall 1112c of the tank.

[0248] In this embodiment, the pressure relief mechanism 3 can be welded to the bottom wall 1112c of the first groove 1112 by through welding. The welding method is simple, and the first weld mark 6 formed after welding can pass through the pressure relief mechanism 3 and be embedded in the bottom wall 1112c of the first groove 1112, which can improve the connection strength between the pressure relief mechanism 3 and the first wall 111. In addition, since the projection of the first weld mark 6 along the thickness direction Z of the first wall 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 the first weld mark 6 is not located in the gap 5 between the pressure relief mechanism 3 and the groove side 1112a, reducing the risk that the groove side 1112a will squeeze the pressure relief mechanism 3 through the first weld mark 6 when the first wall 111 deforms.

[0249] In some embodiments, please continue to refer to Figure 19 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 main body 21.

[0250] 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 that faces away from the interior of the outer casing 1. The side of the pressure relief hole 1111 that faces away from the interior of the outer casing 1 is the side of the pressure relief hole 1111 that faces the exterior of the outer casing 1.

[0251] 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, and the pressure relief mechanism 3 can be installed on the outside of the first wall 111, making the installation of the pressure relief mechanism 3 more convenient.

[0252] In some embodiments, the battery cell 10 further includes a protective member 7, which is located on the side of the pressure relief mechanism 3 away from the main body 21 along the thickness direction Z of the first wall portion, and covers the first groove 1112.

[0253] Along the thickness direction Z of the first wall portion, the side of the pressure relief mechanism 3 facing away from the main body 21 is the outer side of the pressure relief mechanism 3. The protective member 7 covers the first groove 1112, so that the opening 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 opening of the first groove 1112 is entirely located on the protective member 7. The protective member 7 can be a flat plate structure, and can be made of metal, such as copper, iron, aluminum, steel, aluminum alloy, etc., or non-metallic materials, such as plastic, rubber, etc. The protective member 7 is fixed to the first wall portion 111, and can be fixed to the first wall portion 111 by welding, bonding, or other methods.

[0254] In this embodiment, the protective component 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.

[0255] 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.

[0256] The first outer surface 1113 of the first wall portion 111 can be the surface of the first wall portion 111 furthest from the main body portion 21 along the thickness direction. The bottom surface of the second groove 1114 can be the first surface 1115, the first groove 1112 is disposed on the first surface 1115, and the protective member 7 can abut against the first surface 1115 so that the protective member 7 covers the first groove 1112. The second groove 1114 can be a polygonal groove, a circular groove, etc. The protective member 7 can be partially accommodated in the second groove 1114, or it can be entirely located in the second groove 1114.

[0257] 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 on the outside of the outer shell 1.

[0258] In some embodiments, please refer to Figure 20 , Figure 20 This is a partial view of a battery cell 10 provided in some embodiments of this application. 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 facing the main body portion 21.

[0259] It is understandable that the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 facing the inside of the outer casing 1.

[0260] 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 111. The first wall 111 can protect the pressure relief mechanism 3 and reduce the risk of the first wall 111 being damaged by external components.

[0261] In some embodiments, the battery cell 10 further includes a protective member 7, which 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 and covers the pressure relief hole 1111.

[0262] Along the thickness direction Z of the first wall portion, the side of the pressure relief hole 1111 that faces away from the main body 21 is the side of the pressure relief hole 1111 facing the outside of the outer casing 1. Along the thickness direction Z of the first wall portion, the pressure relief mechanism 3 and the protective member 7 are located on both sides of the pressure relief hole 1111, with the pressure relief mechanism 3 located on the side of the pressure relief hole 1111 facing the inside of the outer casing 1, and the protective member 7 located on the side of the pressure relief hole 1111 that faces away from the inside of the outer casing 1.

[0263] The protective component 7 covers the pressure relief hole 1111, and the protective component 7 blocks the pressure relief hole 1111. Along the thickness direction Z of the first wall, the projection of the hole wall surface of the pressure relief hole 1111 can be entirely located on the protective component 7.

[0264] As an example, along the thickness direction Z of the first wall portion, a protrusion 1116 is formed on the side of the first wall portion 111 opposite to the electrode assembly 2, surrounding the pressure relief hole 1111. The protective member 7 is fixed to the protrusion 1116 to cover the pressure relief hole 1111.

[0265] In this embodiment, the protective component 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.

[0266] In some embodiments, please refer to Figure 21 and Figure 22 , Figure 21 Exploded view of the outer casing 1 provided for some embodiments of this application; Figure 22 This is an exploded view of the housing 1 provided in some other embodiments of this application. The housing 1 includes a shell 11 and an end cap 12. The shell 11 has an opening at at least one end along a first direction X, and the shell 11 includes a first wall portion 111. The end cap 12 corresponds to the opening one by one, and the end cap 12 closes the opening.

[0267] A first wall portion 111 is formed in the housing 11, and the first wall portion 111 is at least a part of the housing 11. The housing 11 can be cylindrical, prismatic, etc. In an embodiment where the housing 11 is cylindrical, the entire cylindrical sidewall of the housing 11 can serve as the first wall portion 111; in an embodiment where the housing 11 is prismatic, one wall portion of the housing 11 can serve as the first wall portion 111. As an example, in Figure 21 and Figure 22 In the middle, the shell 11 is rectangular, and one of the walls of the shell 11 is the first wall 111.

[0268] exist Figure 21 In the illustrated embodiment, the housing 11 is a hollow structure with openings at both ends along the first direction X; Figure 22 In the illustrated embodiment, the housing 11 is a hollow structure with an opening at one end along the first direction X.

[0269] When assembling the battery cell 10, the electrode assembly 2 can be installed into the housing 11 first, and then the opening of the housing 11 can be closed by the end cap 12, making the assembly of the battery cell 10 convenient and quick. Since the first wall portion 111 is formed on the housing 11, the pressure relief mechanism 3 is located on the housing 11, which reduces the impact of the discharge medium discharged by the battery cell 10 when it is depressurized through the pressure relief mechanism 3 on the components outside the end cap 12. These components can be current-connecting components, detection components, etc., that are electrically connected to the electrode terminals 4 on the end cap 12.

[0270] In some embodiments, please continue to refer to Figure 21 The shell 11 has openings at both ends opposite each other along the first direction X.

[0271] It is understandable that there are two end caps 12 in the outer casing 1, and the two end caps 12 respectively close the two openings of the casing 11.

[0272] As an example, along the first direction X, the main body 21 ( Figure 21 Both ends of the (not shown) are provided with tabs 22 ( Figure 21 (Not shown), the electrode tabs 22 at both ends of the main body 21 have opposite polarities. Both end caps 12 of the outer casing 1 are provided with electrode terminals 4 (…). Figure 21 (Not shown), along the first direction X, an electrode terminal 4 on one end cap 12 is electrically connected to a tab 22 at one end of the main body 21, and an electrode terminal 4 on the other end cap 12 is electrically connected to a tab 22 at the other end of the main body 21.

[0273] In this embodiment, the housing 11 has openings at both ends opposite to each other along the first direction X. When assembling the battery cell 10, the electrode assembly 2 can enter the housing 11 from either end, which can effectively improve the assembly efficiency of the battery cell 10.

[0274] In some embodiments, please refer to Figure 23 , Figure 23 for Figure 21 The diagram shows the structure of the housing 11. The housing 11 is a one-piece molded structure.

[0275] As an example, the outer casing 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, the first direction X, and the second direction Y of the first wall portion 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 outer casing 1 may be formed from sheet metal by stamping or stretching.

[0276] In this embodiment, the housing 11 is a one-piece molded structure, which can improve the strength of the housing 11, improve the resistance to damage of the housing 11, and improve the service life of the housing 11.

[0277] In some embodiments, please refer to Figures 24-26 , Figure 24 Schematic diagrams of the structure of the housing 11 provided in other embodiments of this application; Figure 25 for Figure 24 The shown is a cross-sectional view of the shell 11 cut along the YZ plane; Figure 26 for Figure 25 The diagram shows the unfolded view of the shell 11. The shell 11 is formed by bending a sheet metal, and the two ends of the sheet metal are connected to each other along the circumference of the opening of the shell 11.

[0278] Taking the housing 11 as an example, which includes a first wall portion 111, a third wall portion 113, a second wall portion 112 and a fourth wall portion 114, the first wall portion 111, the third wall portion 113, the second wall portion 112 and the fourth wall portion 114 are arranged sequentially along the circumference of the opening.

[0279] Along the circumference of the opening, the two ends of the plate are the first end 1121 and the second end 1122, respectively. For example... Figure 26 As shown, before the shell 11 is formed, the sheet metal has two opposing end faces, namely a first end face 1121a and a second end face 1122a. The portion of the sheet metal offset from the first end face 1121a along a direction close to the second end face 1122a by a first preset distance L6 is the first end face 1121 of the sheet metal, and the length of the first end face 1121 is equal to the first preset distance L6. The portion of the sheet metal offset from the second end face 1122a along a direction close to the first end face 1121a by a second preset distance L7 is the second end face 1122 of the sheet metal, and the length of the second end face 1122 is equal to the second preset distance L7. The first preset distance L6 and the second preset distance L7 may be equal or unequal.

[0280] The two ends of the sheet metal (first end 1121 and second end 1122) can be connected in various ways, such as welding, bonding, or hot-melt bonding. The connection point of the two ends can be located on a wall of the housing 11, for example, on the first wall 111, the second wall 112, the third wall 113, or the fourth wall 114; the connection point of the two ends can also be located at the intersection of two adjacent walls of the housing 11, where the intersection is the corner area of ​​the housing 11.

[0281] When forming the shell 11, it is only necessary to bend the sheet and connect the two ends of the sheet to each other. The forming method of the shell 11 is simple and can effectively reduce the forming difficulty of the shell 11.

[0282] In some embodiments, the two ends of the plate are welded together to form a second weld mark 115.

[0283] The second weld mark 115 is formed at the welding positions of the two ends, and the second weld mark 115 can be the part where the two ends are fused together. If the first end face 1121a and the second end face 1122a are arranged opposite each other, the two ends can be welded by seam welding; if the two ends form an overlapping area along the thickness direction Z of the first wall, the overlapping area can be welded by through welding.

[0284] In this embodiment, the two ends of the plate are welded together, which gives the two ends good connection strength and makes the connection more secure.

[0285] In some embodiments, the housing 11 further includes a second wall portion 112, which is disposed opposite to the first wall portion 111 along the thickness direction Z of the first wall portion. The second solder mark portion 115 is located in the second wall portion 112.

[0286] As an example, the two ends of the board together form the second wall portion 112, that is, a part of the second wall portion 112 is the first end portion 1121, and the other part of the second wall portion 112 is the second end portion 1122.

[0287] In this embodiment, the second solder mark 115 is located on the second wall portion 112, such that the second solder mark 115 and the pressure relief mechanism 3 are located on two opposing walls of the housing 11, reducing the impact of the two ends of the plate on the pressure relief mechanism 3 during welding and improving the reliability of the pressure relief mechanism 3. In embodiments where the third wall portion 113 and the fourth wall portion 114 are the walls with the largest area on the outer surface of the housing 1, when the electrode assembly 2 expands, the first wall portion 111 and the second wall portion 112 are less affected by the electrode assembly 2 than the third wall portion 113 and the fourth wall portion 114 are affected by the electrode assembly 2. The deformation of the first wall portion 111 and the second wall portion 112 is less than the deformation of the third wall portion 113 and the fourth wall portion 114. Since the second solder mark 115 is located on the second wall portion 112, the impact of the expansion of the electrode assembly 2 on the second solder mark 115 can be reduced, reducing the risk that the housing 11 will be damaged from the position of the second solder mark 115 due to the expansion of the electrode assembly 2.

[0288] In some embodiments, the outer shell 1 is cuboid in shape, and the first direction X is parallel to the length direction of the outer shell 1.

[0289] As an example, the length of shell 1 is greater than or equal to the height and width of shell 1.

[0290] In this embodiment, the outer shell 1 is rectangular, and its structure is simple and easy to form. When the battery cell 10 is applied to the battery 100, the rectangular shape of the outer shell 1 of the battery cell 10 can reduce the installation gap between the battery cells 10, which is beneficial to improving the volumetric energy density of the battery 100.

[0291] This application provides a battery 100, and any of the above embodiments provide a battery cell 10.

[0292] This application provides an electrical device, wherein the battery cell 10 provided in any of the above embodiments is used to provide electrical energy to the electrical device.

[0293] This application embodiment also provides a battery cell 10, including a housing 1 and an electrode assembly 2, the electrode assembly 2 being housed within the housing 1. The housing 1 is a cuboid, comprising a shell 11 and two end caps 12. Along a first direction X, openings are formed at opposite ends of the shell 11, and each end cap 12 closes one opening. The shell 11 includes a first wall portion 111, a second wall portion 112, a third wall portion 113, and a fourth wall portion 114, which are connected end-to-end. 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, and the third wall portion 113 and the fourth wall portion 114 are disposed opposite each other along a second direction Y. The thickness direction Z of the first wall portion intersects with the first direction X, and the plane formed by the intersection of the thickness direction Z of the first wall portion and the first direction X intersects with the second direction Y. The electrode assembly 2 includes a main body 21 and electrode tabs 22. Electrode tabs 22 are provided at opposite ends of the main body 21 along the first direction X. Electrode terminals 4 are provided on both end caps 12. The electrode 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 electrode 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 portion 111 supports the main body 21 along the direction of gravity. A channel gap 13 is formed between the second wall portion 112 and the main body 21. The channel gap 13 is configured to connect the interior of the outer casing 1 to the spaces located at both ends of the main body 21 along the first direction X. The thickness of the first wall portion 111 is equal to the thickness of the second wall portion 112, and the thicknesses of the third wall portion 113 and the fourth wall portion 114 are both less than the thickness of the first wall portion 111. The first wall portion 111 is provided with N pressure relief mechanisms 3 arranged along the first direction X. The main body portion 21 includes multiple sub-regions 211, which are continuously arranged along the first direction X. The length of the main body portion 21 is L, and the length of the sub-regions 211 is 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 corresponds to a 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, and the area of ​​the first outer surface 1113 is S2, where 0.05 ≤ S1 / S2 ≤ 0.55.

[0294] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0295] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit this application. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized by, The shell comprises a first wall portion provided with N pressure relief mechanisms arranged along a first direction; The electrode assembly is accommodated in the shell, and comprises a main body portion and a tab, at least one end of the main body portion is provided with the tab, the main body portion comprises a plurality of sub-regions, the plurality of sub-regions are continuously arranged along the first direction, the length of the main body portion is L, the length of the sub-region is L1, L = L1 x N, L ≥ 400 mm, and N ≥ 2; Wherein, along the thickness direction of the first wall portion, the projection of each pressure relief mechanism corresponds to one sub-region, and the thickness direction of the first wall portion intersects the first direction. The first wall portion supports the main body portion along the direction of gravity.

2. The battery cell of claim 1, wherein, The shell further comprises a second wall portion, the first wall portion and the second wall portion are oppositely arranged 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 communicate the space located at both ends of the main body portion in the shell along the first direction.

3. The battery cell of claim 2, wherein, The shell further comprises a third wall portion and a fourth wall portion, the third wall portion and the fourth wall portion are oppositely arranged along a second direction, the first wall portion connects the third wall portion and the fourth wall portion, and a plane formed by the thickness direction of the first wall portion and the first direction intersects the second direction; 4. The battery cell of claim 1, wherein, 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. The sum of the predetermined pressure relief areas of the N pressure relief mechanisms is S1, the first wall portion has a first outer surface facing away from the main body portion along the thickness direction of the first wall portion, the area of the first outer surface is S2, and 0.05 ≤ S1 / S2 ≤ 0.

55.

5. The battery cell of claim 1, wherein, 0.15 ≤ S1 / S2 ≤ 0.

35.

6. The battery cell of claim 5, wherein, The predetermined pressure relief areas of the N pressure relief mechanisms are equal.

7. The battery cell of claim 5, wherein the cathode comprises a lithium metal oxide. The shell comprises a first half region and a second half region, along the first direction, the part of the middle cross section of the shell to one end of the shell is the first half region, and the part of the middle cross section of the shell to the other end of the shell is the second half region, the first half region and the second half region are both provided with at least one pressure relief mechanism, and the first direction is perpendicular to the middle cross section.

8. The battery cell of claim 1, wherein, The first wall portion is provided with only two pressure relief mechanisms, and the two pressure relief mechanisms are located in the first half region and the second half region respectively.

9. The battery cell of claim 8, wherein the cathode comprises a lithium metal oxide. The pressure relief mechanism is provided with a notch groove, along the first direction, the length of the shell is L2, the minimum distance between the notch grooves of two adjacent pressure relief mechanisms is L3, L2 > L, and L3 / L2 ≥ 1 / 6.

10. The battery cell of claim 1, wherein, L3 / L2 ≥ 1 / 4.

11. The battery cell of claim 10, wherein the cathode comprises a lithium metal oxide. L2 ≥ 500 mm; and / or, L3 ≥ 300 mm.

12. The battery cell as described in claim 10, characterized in that, Along the first direction, the length of the shell is L2, the pressure relief mechanism is provided with a notch groove, the maximum span of the notch grooves of the N pressure relief mechanisms along the first direction is D1, and 0.2 ≤ D1 / L2 ≤ 0.

6.

13. The battery cell as described in claim 1, characterized in that, ​ 14. The battery cell of any one of claims 1-13, wherein, The pressure relief mechanism is provided with a score groove, and the pressure relief mechanism forms a weak portion at a region where the score groove is provided, the weak portion being configured to be able to be split to release pressure inside the battery cell.

15. The battery cell as described in claim 14, characterized in that, The score groove has a groove opening facing the main body portion in a thickness direction of the first wall portion.

16. The battery cell as described in claim 14, characterized in that, The pressure relief mechanism includes a pressure relief zone configured to be opened when the weak portion is split.

17. The battery cell as described in claim 16, characterized in that, The score groove is a groove extending along a closed trajectory, and the score groove is provided around the pressure relief zone.

18. The battery cell of any one of claims 1-13, wherein, The pressure relief mechanism is integrally formed with the first wall portion.

19. The battery cell of any one of claims 1-13, wherein, The pressure relief mechanism is provided separately from the first wall portion, the first wall portion is provided with a pressure relief hole, and the pressure relief mechanism is mounted to the first wall portion and covers the pressure relief hole.

20. The battery cell of claim 19, wherein, The first wall portion is provided with a first groove including a groove side surface surrounding a first groove bottom surface and the pressure relief hole is provided on the first groove bottom surface, and the pressure relief mechanism is provided in the first groove and abuts against the first groove bottom surface. A gap is formed between the groove side surface and the pressure relief mechanism in at least a part of a circumferential direction of the first groove.

21. The battery cell of claim 20, wherein, The groove side surface includes a first region in which a gap is formed with the pressure relief mechanism, and a length of the first region is L4 and a circumference of the groove side surface is L5 in the circumferential direction of the first groove, and 0.2≤L4 / L5≤1 is satisfied.

22. The battery cell as described in claim 20, characterized in that, A gap is formed between the groove side surface and the pressure relief mechanism in the entire circumferential direction of the first groove.

23. The battery cell as described in claim 20, characterized in that, The pressure relief mechanism is welded to a groove bottom wall of the first groove and forms a first weld mark portion.

24. The battery cell as described in claim 23, characterized in that, A projection of the first weld mark portion is entirely located in the pressure relief mechanism in a thickness direction of the first wall portion.

25. The battery cell of any one of claims 20-24, wherein, The pressure relief mechanism is located on a side of the pressure relief hole facing away from the main body portion in the thickness direction of the first wall portion.

26. The battery cell of claim 25, wherein, The battery cell further includes a shield located on a side of the pressure relief mechanism facing away from the main body portion in the thickness direction of the first wall portion, and the shield covers the first groove.

27. The battery cell as described in claim 26, characterized in that, The first wall portion has a first outer surface facing away from the main body portion in the thickness direction of the first wall portion, the first outer surface is provided with a second groove, the first groove is provided on a groove bottom surface of the second groove, and the shield is at least partially accommodated in the second groove.

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

29. The battery cell as described in claim 28, characterized in that, The battery cell further includes a shield located on a side of the pressure relief hole facing away from the main body portion in the thickness direction of the first wall portion, and the shield covers the pressure relief hole.

30. The battery cell of any one of claims 1-13, wherein, The housing includes: a housing body having an opening formed at at least one end in the first direction, the housing body including the first wall portion; an end cover corresponding to the opening, the end cover closing the opening.

31. The battery cell of claim 30, wherein the cathode comprises a lithium metal oxide. The housing body has the opening formed at both ends opposite to each other in the first direction.

32. The battery cell as described in claim 30, characterized in that, The housing body is an integrally formed structure.

33. The battery cell as described in claim 30, characterized in that, The housing body is formed by bending a plate material, and a first end and a second end of the plate material are connected to each other in a circumferential direction of the opening.

34. The battery cell as described in claim 33, characterized in that, The first end and the second end are welded to each other and form a second weld mark portion.

35. The battery cell of claim 34, wherein the cathode comprises a lithium metal oxide. The shell further comprises a second wall portion, the first wall portion and the second wall portion are oppositely arranged along a thickness direction of the first wall portion. The second welding mark portion is located on the second wall portion.

36. The battery cell of any one of claims 1-13, wherein, The shell is cuboid, and the first direction is parallel to a length direction of the shell.

37. A battery, comprising: The battery cell as claimed in any one of claims 1 to 36.

38. An electrical device, comprising: The battery cell as claimed in any one of claims 1 to 36, the battery cell being used to provide electric energy for the electric device.

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