Battery monomer, battery and electric equipment

Abstract

The embodiment of the invention 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] This application is a divisional application based on the invention with application number 2023111199944, application date September 1, 2023, applicant Contemporary Amperex Technology Co., Ltd., and invention name “Battery Cell, Battery and Electrical Equipment”. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a battery cell, a battery and an electrical device. Background Art

[0003] Batteries are widely used in electronic devices, such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes and power tools, etc.

[0004] In battery technology, a pressure relief mechanism can be set in the battery cell to release pressure when the battery cell is in thermal runaway. For general battery cells, there is still a situation where pressure relief is not timely, and the reliability of the battery cell is poor. Therefore, how to improve the reliability of battery cells is a technical problem that needs to be solved urgently in battery technology. Summary of the invention

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

[0006] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell and an electrode assembly; the shell comprises a first wall portion, and the first wall portion is provided with N pressure relief mechanisms arranged along a first direction; the electrode assembly is accommodated in the shell, and the electrode assembly comprises a main body portion and a pole ear, and at least one end of the main body portion is provided with a pole ear, and the main body portion comprises a plurality of sub-regions, and along the first direction, the plurality of sub-regions are continuously arranged, the length of the main body portion is L, and the length of the sub-region is L1, L=L1×N, L≥400mm, and N≥2; wherein, along the thickness direction of the first wall portion, the projection of each pressure relief mechanism is correspondingly located within a sub-region, and the thickness direction of the first wall portion intersects with the first direction.

[0007] In the above technical solution, the projection of each pressure relief mechanism along the thickness direction of the first wall portion corresponds to a sub-region, so that each sub-region can correspond to a pressure relief mechanism on the outer shell, and each pressure relief mechanism can discharge the emission medium generated by the thermal runaway of a corresponding sub-region. If thermal runaway occurs in any sub-region, the emission medium generated by the thermal runaway can be quickly discharged through the corresponding pressure relief mechanism, which can effectively improve the timeliness of the pressure relief of the battery cell, thereby improving the reliability of the battery cell.

[0008] In some embodiments, the first wall supports the main body in the direction of gravity. In this way, the discharge inside the shell can be discharged from the bottom of the shell. Since the first wall is the wall supporting the main body in the shell, the first wall is pressed by the main body, and the area near the first wall inside the shell is more likely to be blocked and blocked, which is not conducive to the discharge of the discharge medium. However, since the first wall is provided with multiple pressure relief mechanisms, it is more conducive to the discharge of the discharge medium near the first wall inside the shell, thereby improving the reliability of the battery cell.

[0009] In some embodiments, the housing further includes a second wall portion, and the first wall portion and the second wall portion are arranged opposite to each other along the thickness direction of the first wall portion, and a channel gap is formed between the second wall portion and the main body portion, and the channel gap is configured to connect the spaces inside the housing located at both ends of the main body portion along the first direction. The channel gap can connect the spaces inside the housing located at both ends of the main body portion along the first direction, and when a sub-region located at one end of the main body portion undergoes thermal runaway, the discharge medium accumulated near one end of the main body portion can be discharged through the pressure relief mechanism corresponding to the sub-region, and can also flow to the other end of the main body portion through the channel gap, and be discharged through the pressure relief mechanism corresponding to the sub-region at the other end of the main body portion, so that the discharge medium inside the battery cell can be quickly discharged, thereby improving the timeliness of the pressure relief of the battery cell.

[0010] In some embodiments, the housing further includes a third wall portion and a fourth wall portion, the third wall portion and the fourth wall portion are arranged opposite to each other along the second direction, the 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 with the second direction; wherein the thickness of the third wall portion and the thickness of the fourth wall portion are both less than the thickness of the first wall portion. In this way, the thickness of the first wall portion can be increased, the deformation resistance of the first wall portion can be improved, and the risk of excessive deformation of the first wall portion due to expansion of the battery cell can be reduced, thereby reducing the influence of the deformation of the first wall portion on the pressure relief mechanism, reducing the risk of the pressure relief mechanism opening pressure relief in advance, and improving the service life of the pressure relief mechanism.

[0011] In some embodiments, the sum of the predetermined pressure relief areas of the N pressure relief mechanisms is S1, and along the thickness direction of the first wall portion, the first wall portion has a first outer surface away from the main body portion, and the area of ​​the first outer surface is S2, 0.05≤S1 / S2≤0.55. S1 / S2≥0.05 makes the total pressure relief area of ​​the N pressure relief mechanisms larger, which is beneficial to improving the pressure relief rate of the battery cell and improving the timeliness of the pressure relief of the battery cell; S1 / S2≤0.55 is beneficial to improving the strength of the first wall portion.

[0012] In some embodiments, 0.15≤S1 / S2≤0.35.

[0013] In some embodiments, the predetermined pressure relief areas of the N pressure relief mechanisms are equal, so that the pressure relief capabilities of all the pressure relief mechanisms on the first wall portion are substantially consistent, and the difficulty of forming each pressure relief mechanism can be reduced.

[0014] In some embodiments, the housing includes a first half-section and a second half-section. Along a first direction, the portion from the middle section of the housing to one end of the housing is the first half-section, and the portion from the middle section of the housing to the other end of the housing is the second half-section. The first half-section and the second half-section are both provided with a pressure relief mechanism, and the first direction is perpendicular to the middle section. When the battery cell is in thermal runaway, pressure relief can be performed through the pressure relief mechanism of the first half-section and the pressure relief mechanism of the second half-section, so that the discharge medium in the housing located in the first half-section can be discharged more quickly through the pressure relief mechanism of the first half-section, and the discharge medium in the housing located in the second half-section can be discharged more quickly through the pressure relief mechanism of the second half-section, thereby improving the timeliness of pressure relief of the battery cell.

[0015] In some embodiments, the first wall is provided with only two pressure relief mechanisms, which are located in the first half area and the second half area, respectively. In this way, there are not too many pressure relief mechanisms on the first wall, which can reduce the manufacturing cost of the battery cell while achieving rapid pressure relief of the battery cell, thus achieving better economy.

[0016] In some embodiments, the pressure relief mechanism is provided with a notched groove, and along the first direction, the length of the shell is L2, and the minimum distance between the notched grooves of two adjacent pressure relief mechanisms is L3, L2>L, L3 / L2≥1 / 6. In this way, the minimum distance between the notched grooves of two adjacent pressure relief mechanisms is not too small, so that each pressure relief mechanism can correspond to a larger area of ​​the main body, fully utilize each pressure relief mechanism, and improve the timeliness of pressure relief of the battery cell.

[0017] In some embodiments, L3 / L2≥1 / 4.

[0018] In some embodiments, L2≥500mm; and / or, L3≥300mm. L2≥500mm, the shell is relatively large in the first direction, which can meet the large capacity requirements of the battery cell. L3≥300mm, so that the minimum distance between two adjacent pressure relief mechanisms is not too small, so that each pressure relief mechanism can correspond to a larger area of ​​the main body, and the discharge medium in the larger area of ​​the main body can be discharged through the corresponding pressure relief mechanism, making full use of each pressure relief mechanism, and improving the timeliness of pressure relief of the battery cell.

[0019] In some embodiments, along the first direction, the length of the housing is L2, the pressure relief mechanism is provided with a notch groove, and the sum of the maximum spans of the notch grooves of the N pressure relief mechanisms along the first direction is D1, 0.2≤D1 / L2≤0.6. D1 / L2≥0.2, so that the sum of the maximum spans of the notch grooves of the multiple pressure relief mechanisms on the first wall along the first direction is larger, which can increase the total pressure relief area of ​​the multiple pressure relief mechanisms on the first wall, which is beneficial to improving the pressure relief rate of the battery cell. D1 / L2≤0.6, so that the sum of the maximum spans of the notch grooves of the multiple pressure relief mechanisms on the first wall along the first direction is not too large, which is beneficial to improving the strength of the first wall.

[0020] In some embodiments, the pressure relief mechanism is provided with a notched groove, and the pressure relief mechanism forms a weak portion in the area where the notched groove is provided, and the weak portion is configured to be able to rupture to release the pressure inside the battery cell. The weak portion is formed in the corresponding area of ​​the pressure relief mechanism by providing the notched groove, and the method of forming the weak portion is simple. The weak portion is a weaker area in the pressure relief mechanism, and the weak portion is more easily destroyed when the battery cell is in thermal runaway, so as to release the pressure in time.

[0021] In some embodiments, along the thickness direction of the first wall, the notch of the notch faces the main body, so that the weak portion is not easily torn when the first wall is deformed due to the expansion of the battery cell, thereby improving the long-term reliability of the pressure relief mechanism.

[0022] In some embodiments, the pressure relief mechanism includes a pressure relief zone, which is configured to be able to open when the weak portion is broken. During pressure relief, the pressure relief zone can be opened with the weak portion as a boundary, thereby increasing the pressure relief area of ​​the pressure relief mechanism.

[0023] In some embodiments, the notched groove is a groove extending along a closed track, and the notched groove is arranged around the pressure relief area. During the pressure relief process, after the pressure relief mechanism is cracked along the notched groove, the pressure relief area can be separated from the first wall, thereby increasing the pressure relief area and improving the pressure relief rate of the battery cell.

[0024] In some embodiments, the pressure relief mechanism is integrally formed with the first wall portion, so that the reliability of the pressure relief mechanism is higher, the connection process between the pressure relief mechanism and the first wall portion is omitted, and the production cost of the battery cell can be reduced.

[0025] In some embodiments, the pressure relief mechanism is separately arranged from the first wall portion, the first wall portion is provided with a pressure relief hole, the pressure relief mechanism is installed 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 produced and assembled separately, with low production difficulty and high efficiency.

[0026] In some embodiments, the first wall portion is provided with a first groove, the first groove includes a groove side surface and a first groove bottom surface, the groove side surface is arranged around the first groove bottom surface, the pressure relief hole is arranged on the first groove bottom surface, the pressure relief mechanism is arranged in the first groove and abuts against the first groove bottom surface; wherein, a gap is formed between at least a portion of the groove side surface along the circumference of the first groove and the pressure relief mechanism. When the first wall portion is deformed due to the expansion of the battery cell, the gap between the pressure relief mechanism and the groove side surface can provide a buffer space for the pressure relief mechanism, reduce the risk of the groove side surface squeezing the pressure relief mechanism and causing the pressure relief mechanism to deform, thereby reducing the risk of the pressure relief mechanism opening prematurely during normal use of the battery cell, and increasing the service life of the pressure relief mechanism.

[0027] In some embodiments, the groove side includes a first area with a gap formed with the pressure relief mechanism, and along the circumference of the first groove, the length of the first area is L4, and the circumference of the groove side is L5, satisfying: 0.2≤L4 / L5≤1. In this way, a gap is formed between the longer part of the groove side in the circumferential direction and the pressure relief mechanism, reducing the range of the groove side extruding the pressure relief mechanism when the first wall portion is deformed, and further reducing the risk of the pressure relief mechanism opening prematurely during normal use of the battery cell.

[0028] In some embodiments, a gap is formed between the entire circumference of the first groove and the pressure relief mechanism. In this way, there is a gap between the entire circumference of the groove side and the pressure relief mechanism, and the 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 portion is deformed, and further reducing the risk of the pressure relief mechanism opening prematurely during normal use of the battery cell.

[0029] In some embodiments, the pressure relief mechanism is welded to the bottom wall of the first groove to form a first welded portion, so that the pressure relief mechanism is fixed to the first wall portion, and the connection strength between the pressure relief mechanism and the first wall portion is improved.

[0030] In some embodiments, along the thickness direction of the first wall portion, the projection of the first weld mark is entirely located on the pressure relief mechanism. In this way, the pressure relief mechanism can be welded to the bottom wall of the first groove by penetration welding. The welding method is simple, and the first weld mark formed after welding can pass through the pressure relief mechanism and be embedded in the bottom wall of the first groove, which can improve the connection strength between the pressure relief mechanism and the first wall portion. In addition, since the projection of the first weld mark along the thickness direction of the first wall portion is located on the pressure relief mechanism, the first weld mark does not protrude from the edge of the pressure relief mechanism, and the first weld mark is not located in the gap between the pressure relief mechanism and the side surface of the groove, which reduces the risk of the side surface of the groove squeezing the pressure relief mechanism through the first weld mark when the first wall portion is deformed.

[0031] In some embodiments, along the thickness direction of the first wall portion, the pressure relief mechanism is located on the side of the pressure relief hole away from the main body portion. In this way, the pressure relief mechanism can be installed on the outside of the first wall portion, making the pressure relief mechanism more convenient to install.

[0032] In some embodiments, the battery cell further includes a protective member, which is located on a side of the pressure relief mechanism away from the main body along the thickness direction of the first wall portion, and 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.

[0033] 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, the first outer surface is provided with a second groove, the first groove is provided at the groove 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, and the space outside the housing occupied by the protective member can be reduced.

[0034] In some embodiments, along the thickness direction of the first wall portion, the pressure relief mechanism is located on the side of the pressure relief hole facing the main body portion. In this way, the pressure relief mechanism can be installed on the inner side of the first wall portion, and the first wall portion can protect the pressure relief mechanism and reduce the risk of the first wall portion being damaged by external components.

[0035] In some embodiments, the battery cell further includes a protective member, which is located on a side of the pressure relief hole away from the main body along the thickness direction of the first wall portion and covers the pressure relief hole. The protective member can protect the pressure relief mechanism and reduce the risk of external substances (impurities, electrolyte) entering the pressure relief hole and corroding the pressure relief mechanism.

[0036] In some embodiments, the housing includes a shell and an end cap; the shell is formed with an opening at at least one end along the first direction, and the shell includes a first wall portion; the end cap corresponds to the opening one by one, and the end cap closes the opening. When assembling the battery cell, the electrode assembly can be first loaded into the shell, and then the opening of the shell is closed by the end cap, so that the assembly of the battery cell is convenient and quick.

[0037] In some embodiments, both ends of the housing along the first direction are formed with openings. When assembling the battery cell, the electrode assembly can enter the housing from any end of the housing, which can effectively improve the assembly efficiency of the battery cell.

[0038] In some embodiments, the housing is an integrally formed structure, which can improve the strength of the housing, improve the anti-destruction ability of the housing, and increase the service life of the housing.

[0039] In some embodiments, the shell is formed by bending a plate, and the first and second ends of the plate are connected to each other along the circumference of the opening. When forming the shell, it is only necessary to bend the plate and connect the first and second ends of the plate to each other. The forming method of the shell is simple, which can effectively reduce the difficulty of forming the shell.

[0040] In some embodiments, the two ends are connected by welding to form a second welded portion, so that the two ends have good connection strength and are more firmly connected.

[0041] In some embodiments, the housing further comprises a second wall portion, and the first wall portion and the second wall portion are arranged opposite to each other along the thickness direction of the first wall portion; wherein the second weld portion is located on the second wall portion. The second weld portion and the pressure relief mechanism are located on two opposite walls of the housing, thereby reducing the influence of the two ends of the plate on the pressure relief mechanism during welding and improving the reliability of the pressure relief mechanism.

[0042] In some embodiments, the outer shell is in the shape of a rectangular parallelepiped, and the first direction is parallel to the length direction of the outer shell. The outer shell has a simple structure and is easy to form. When the battery cell is applied to the battery, the outer shell of the battery cell is in the shape of a rectangular parallelepiped, which can reduce the installation gap between the battery cells and is conducive to improving the volume energy density of the battery.

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

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

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

[0046] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0047] Figure 2 An exploded view of a battery provided for some embodiments of the present application;

[0048] Figure 3 An axonometric view of a battery cell provided for some embodiments of the present application;

[0049] Figure 4 for Figure 3An exploded view of a battery cell is shown;

[0050] Figure 5 A cross-sectional view of a battery cell provided for some embodiments of the present application;

[0051] Figure 6 for Figure 5 A cross-sectional view of the housing shown along the YZ plane;

[0052] Figure 7 for Figure 5 A view of the battery cell shown;

[0053] Figure 8 for Figure 6 A partial enlarged view of the housing B shown;

[0054] Fig. 9 A partial view of a first wall portion provided for some embodiments of the present application;

[0055] Fig.10 A partial view of a first wall portion provided for some other embodiments of the present application;

[0056] Fig.11 A partial view of a first wall portion provided for some further embodiments of the present application;

[0057] Fig.12 An exploded view of a battery cell provided in some other embodiments of the present application;

[0058] Fig.13 for Fig.12 A cross-sectional view of a battery cell is shown;

[0059] Fig.14 for Fig.13 A partial enlarged view of the battery cell C shown;

[0060] Fig.15 for Fig.14 a cross-sectional view of the first wall portion shown;

[0061] Fig.16 An assembly diagram of a pressure relief mechanism and a first wall portion provided in some embodiments of the present application;

[0062] Fig.17 for Fig.16 A schematic structural diagram of the first wall portion shown;

[0063] Fig.18 Assembly diagram of the pressure relief mechanism and the first wall portion provided in some other embodiments of the present application;

[0064] Fig.19 A partial view of a battery cell provided for some other embodiments of the present application;

[0065] Fig. 20 A partial view of a battery cell provided for some further embodiments of the present application;

[0066] Fig.21 An exploded view of a housing provided for some embodiments of the present application;

[0067] Fig. 22 An exploded view of a housing provided for some other embodiments of the present application;

[0068] Fig.23 for Fig.21 A schematic diagram of the structure of the housing shown;

[0069] Fig.24 A schematic diagram of the structure of a housing provided in some other embodiments of the present application;

[0070] Fig.25 for Fig.24 A cross-sectional view of the shell shown along the YZ plane;

[0071] Fig.26 for Fig.25 An expanded view of the housing is shown.

[0072] Icons: 1-shell; 11-shell; 111-first wall; 1111-pressure relief hole; 1112-first groove; 1112a-groove side; 1112b-first groove bottom; 1112c-groove bottom wall; 1112d-first area; 1112e-first side; 1112f-second side; 1113-first outer surface; 1114-second groove; 1115-first surface; 1116-protrusion; 112-second wall; 1121-first end; 1121a-first end surface; 1122-second end; 1122a-second end surface; 113-third wall; 114-fourth wall; 115-second welded portion; 12-end cover; 13-channel gap; 14-first space; 15-second space; 16-first half area; 17- The second half area; 2-electrode assembly; 21-main body; 211-sub-area; 22-ear; 3-pressure relief mechanism; 31-notched groove; 311-first arc segment; 312-first straight 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 weld print; 7-protective member; 10-battery cell; 20-housing; 201-first part; 202-second part; 100-battery; 200-controller; 300-motor; 1000-vehicle; W-mid section; X-first direction; Y-second direction; Z-thickness direction of the first wall. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0074] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0075] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0076] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0077] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0078] The term "plurality" used in the present application refers to two or more (including two).

[0079] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0080] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, and the like.

[0081] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode to reduce the risk of short circuit between the positive and negative electrodes, while allowing active ions to pass through.

[0082] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0083] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is disposed on either or both of the two facing surfaces of the positive electrode current collector.

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

[0085] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 (also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds, etc.

[0086] In some embodiments, the positive electrode may be a foamed metal. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, or a carbon foam. When the foamed metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foamed metal, but of course, the positive electrode active material may also be provided. As an example, a lithium source material, potassium metal or sodium metal may also be filled or / and deposited in the foamed metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[0087] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0088] 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, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. can be used. The foamed metal can be a foamed nickel, a foamed copper, a foamed aluminum, a foamed alloy, or a foamed carbon, etc. The composite current collector can include a polymer material base and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0089] 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.

[0090] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0091] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0092] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0093] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical stability and mechanical stability.

[0094] As an example, the material of the separator may include at least one of glass fiber, non-woven 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 may be attached to the surface of the positive and negative electrodes.

[0095] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transmit ions and isolate the positive and negative electrodes.

[0096] In some embodiments, the battery cell further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The electrolyte can be liquid, gel or solid. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0097] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0098] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0099] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0100] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0101] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, and the like.

[0102] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0103] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0104] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0105] In some embodiments, the electrode assembly is a laminate structure.

[0106] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be provided respectively, and the plurality of positive electrode sheets and the plurality of negative electrode sheets may be alternately stacked.

[0107] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0108] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded sections that are stacked.

[0109] As an example, a plurality of separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0110] As an example, the separator may be disposed continuously, and may be disposed between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0111] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0112] In some embodiments, the electrode assembly is provided with tabs, which can lead current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0113] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0114] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a polygonal battery, such as a hexagonal battery.

[0115] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0116] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0117] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are accommodated in the case.

[0118] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0119] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0120] The development of battery technology must take into account many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the reliability of battery cells must also be considered.

[0121] In battery technology, a pressure relief mechanism can be set in a battery cell to improve the reliability of the battery cell. The pressure relief mechanism on the battery cell has an important impact on the reliability of the battery. For example, when a short circuit or overcharge occurs, thermal runaway may occur inside the battery cell, causing a sudden increase in pressure or temperature. In this case, the pressure relief mechanism can release the internal pressure and temperature to the outside to reduce the probability of explosion or fire in the battery cell.

[0122] In a general battery cell, the battery cell includes a shell and an electrode assembly, the electrode assembly is contained in the shell, and the electrode assembly includes a main body and a tab, and the tab is provided at one or both ends of the main body along a preset direction. The shell is provided with only one pressure relief mechanism, and the pressure relief mechanism is located at one end of the shell along a preset direction. When the battery cell is in thermal runaway, the discharge medium inside the shell is discharged through the pressure relief mechanism to achieve the purpose of releasing the pressure inside the battery cell. In such a battery cell, when the length of the main body is greater than or equal to 400 mm, when the battery cell is in thermal runaway, the discharge medium generated in the area of ​​the main body close to the pressure relief mechanism can flow to the pressure relief mechanism, but the discharge medium generated in the area of ​​the main body far from the pressure relief mechanism is difficult to flow to the pressure relief mechanism, which is prone to untimely pressure relief, and the reliability of the battery cell is poor.

[0123] In view of this, an embodiment of the present application provides a battery cell, wherein N pressure relief mechanisms arranged along a first direction are arranged on the first wall portion of the outer shell, L ≥ 400 mm, N ≥ 2, and the main part of the electrode assembly is divided into N sub-regions continuously arranged along the first direction, and the lengths of each sub-region along the first direction are equal, and along the thickness direction of the first wall portion, the projection of each pressure relief mechanism is correspondingly located within a sub-region.

[0124] In such a battery cell, when the length of the main body is greater than or equal to 400 mm, each sub-region can correspond to a pressure relief mechanism on the outer shell, and each pressure relief mechanism can discharge the emission medium generated by the thermal runaway of a corresponding sub-region. If thermal runaway occurs in any sub-region, the emission medium generated by the thermal runaway can be quickly discharged through the corresponding pressure relief mechanism, which can effectively improve the timeliness of the pressure relief of the battery cell, and thus improve the reliability of the battery cell.

[0125] The battery cells described in the embodiments of the present application are suitable for batteries and electrical equipment using the battery cells.

[0126] Electrical equipment may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, electric tools, and the like. Vehicles may be fuel vehicles, gas vehicles, or new energy vehicles, and new energy vehicles may be pure electric vehicles, hybrid vehicles, or extended-range vehicles, and the like; spacecraft include airplanes, rockets, space shuttles, and spacecraft, and the like; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, and the like. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical equipment.

[0127] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0128] Please refer to Figure 1 , Figure 1 The schematic diagram of the structure of the vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 is provided with a battery 100 inside, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000, for example, the battery 100 can be used as an operating power source of the vehicle 1000.

[0129] The vehicle 1000 may further include a controller 200 and a motor 300 , wherein the controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, to meet the power requirements of starting, navigating, and driving the vehicle 1000 .

[0130] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0131] Please refer to Figure 2 , Figure 2 The exploded view of the battery 100 provided in some embodiments of the present application. The battery 100 includes a battery cell 10 and a box body 20, and the battery cell 10 is accommodated in the box body 20.

[0132] Among them, the box body 20 is a component for accommodating the battery cell 10. The box body 20 provides a storage space for the battery cell 10. The box body 20 can adopt a variety of structures. In some embodiments, the box body 20 may include a first part 201 and a second part 202, and the first part 201 and the second part 202 cover each other to define a storage space for accommodating the battery cell 10. The first part 201 and the second part 202 may be in a variety of shapes, such as a rectangular parallelepiped, a cylindrical shape, etc. The first part 201 may be a hollow structure with one side open, and the second part 202 may also be a hollow structure with one side open, and the open side of the second part 202 covers the open side of the first part 201, so as to form a box body 20 with a storage space. It is also possible that the first part 201 is a hollow structure with one side open, and the second part 202 is a plate-like structure, and the second part 202 covers the open side of the first part 201, so as to form a box body 20 with a storage space. The first part 201 and the second part 202 can be sealed by a sealing element, and the sealing element can be a sealing ring, a sealant, etc.

[0133] In the battery 100, there may be one or more battery cells 10. If there are more than one battery cell 10, the battery cells 10 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the battery cells 10 are both connected in series and in parallel. The battery modules may be connected in series, in parallel, or in a mixed connection to form a battery module, and then the battery modules may be connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 20. Alternatively, all the battery cells 10 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by all the battery cells 10 may be accommodated in the box 20.

[0134] In some embodiments, the battery 100 may further include a busbar, through which multiple battery cells 10 may be electrically connected to achieve series connection, parallel connection, or hybrid connection of multiple battery cells 10. The busbar may be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0135] Please refer to Figure 3 and Figure 4 , Figure 3 An axonometric view of a battery cell 10 provided in some embodiments of the present 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.

[0136] The housing 1 is a component for accommodating the electrode assembly 2 and electrolyte, etc. As an example, the housing 1 may include a shell 11 and an end cap 12 .

[0137] The housing 11 may be a hollow structure with an opening at one end, or a hollow structure with openings at opposite ends. The housing 11 may be in various shapes, such as a cylindrical shape, a prism shape, etc. The housing 11 may be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc.

[0138] The end cap 12 is a component that closes the opening of the shell 11 to isolate the internal environment of the battery cell 10 from the external environment. The end cap 12 and the shell 11 together define a receiving space for accommodating the electrode assembly 2, the electrolyte and other components. The shape of the end cap 12 can be adapted to the shape of the shell 1. For example, the shell 11 is a rectangular parallelepiped structure, and the end cap 12 is a rectangular plate structure adapted to the shell 1. For another example, the shell 11 is a cylindrical structure, and the end cap 12 is a circular plate structure adapted to the shell 11. The material of the end cap 12 can also be a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The material of the end cap 12 and the shell 11 can be the same or different.

[0139] In the embodiment where the housing 11 is opened at one end, one end cap 12 may be provided. In the embodiment where the housing 11 is opened at two opposite ends, two end caps 12 may be provided, and 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 a receiving space.

[0140] The pressure relief mechanism 3 is a component for releasing the pressure inside the battery cell 10. When the pressure inside the battery cell 10 reaches a threshold, the discharge medium inside the battery cell 10 is discharged through the pressure relief mechanism 3 to achieve the purpose of pressure relief. The discharge medium includes but is not limited to: electrolyte, dissolved or split positive and negative electrode sheets, fragments of separators, gas generated by the reaction, flame, etc. The pressure relief mechanism 3 can be set on the housing 11 or on the end cover 12.

[0141] In some embodiments, the battery cell 10 may further include an electrode terminal 4, which is disposed on the housing 1 and is used to electrically connect to the tab 22 of the electrode assembly 2 to input or output the electrical energy of the battery cell 10. The electrode terminal 4 may be disposed on the shell 11 of the housing 1 or on the end cover 12 of the housing 1. The electrode terminal 4 and the tab 22 may be directly connected, for example, the electrode terminal 4 and the tab 22 are directly welded. The electrode terminal 4 and the tab 22 may also be indirectly connected, for example, the electrode terminal 4 and the tab 22 are indirectly connected through a current collecting member.

[0142] As an example, Figure 4As shown, the shell 11 is a hollow structure with openings formed at two opposite ends, and end covers 12 are provided at the opposite ends of the shell 11. Electrode terminals 4 are provided on the end covers 12 at both ends of the shell 11, and pole ears 22 are formed at the opposite ends of the electrode assembly 2. The pole ear 22 at one end of the electrode assembly 2 is a positive pole ear, and the pole ear 22 at the other end of the electrode assembly 2 is a negative pole ear. The electrode terminal 4 on one end cover 12 is electrically connected to the positive pole ear, and the electrode terminal 4 on the other end cover 12 is electrically connected to the negative pole ear.

[0143] Please refer to Figure 5 , Figure 5 A cross-sectional view of a battery cell 10 provided in some embodiments of the present application. The present application provides a battery cell 10, which includes a housing 1 and an electrode assembly 2. The housing 1 includes a first wall portion 111, and the first wall portion 111 is provided with N pressure relief mechanisms 3 arranged along a first direction X. The electrode assembly 2 is accommodated in the housing 1, and the electrode assembly 2 includes a main body 21 and a pole ear 22, and at least one end of the main body 21 is provided with a pole ear 22. The main body 21 includes a plurality of sub-regions 211, and along the first direction X, the plurality of sub-regions 211 are continuously arranged, the length of the main body 21 is L, and the length of the sub-region 211 is L1, L=L1×N, L≥400mm, N≥2; wherein, along the thickness direction Z of the first wall portion, the projection of each pressure relief mechanism 3 is correspondingly located in a sub-region 211, and the thickness direction Z of the first wall portion intersects with the first direction X.

[0144] The housing 1 may be cylindrical, prism-shaped, etc. The prism may be a triangular prism, a quadrangular prism, a pentagonal prism, a hexagonal prism, etc. The quadrangular prism may include a cuboid, a cube, etc. In the embodiment where the housing 1 is cylindrical, the first direction X may be parallel to the axial direction of the housing 1; in the embodiment where the housing 1 is a cuboid, the first direction X may be parallel to the length direction of the housing 1.

[0145] The first wall portion 111 may be the end cover 12 of the housing 1, and it is understood that the end cover 12 is provided with a pressure relief mechanism 3; the first wall portion 111 may also be at least one wall portion of the shell 11 in the housing 1, and it is understood that the housing 1 is provided with a pressure relief mechanism 3. The pressure relief mechanisms 3 on the first wall portion 111 may be two, three, four, five, six or more, so N may be 2, 3, 4, 5, 6, etc.

[0146] The pressure relief mechanism 3 is a component for releasing the pressure inside the battery cell 10. When the pressure inside the battery cell 10 reaches a threshold, the discharge medium inside the battery cell 10 is discharged through the pressure relief mechanism 3 to achieve the purpose of pressure relief. The discharge medium includes but is not limited to: electrolyte, dissolved or split positive and negative electrode sheets, fragments of separators, gas generated by the reaction, flame, etc. The pressure relief mechanism 3 and the first wall portion 111 can be integrally formed or separately provided.

[0147] The main body 21 has two opposite ends along a preset direction. The tab 22 may be disposed at one end of the main body 21, or at both opposite ends of the main body 21. The preset direction may be parallel to the first direction X, or may intersect with it. For example, the preset direction is perpendicular to the first direction X. As an example, the preset direction is parallel to the first direction X, that is, the tab 22 is disposed at least at one end of the main body 21 along the first direction X. Figure 5 In the illustrated embodiment, both ends of the main body 21 in the first direction X are provided with tabs 22, the tab 22 at one end is a positive tab, and the tab 22 at the other end is a negative tab. Both ends of the housing 1 are provided with electrode terminals 4, the electrode terminal 4 at one end of the housing 1 is electrically connected to the tab 22 at one end of the main body 21, and the electrode terminal 4 at the other end of the housing 1 is electrically connected to the tab 22 at the other end of the main body 21.

[0148] The electrode assembly 2 may include a positive electrode sheet, a negative electrode sheet and a separator. The electrode assembly 2 may be a winding structure formed by winding the positive electrode sheet, the separator and the negative electrode sheet, or a laminated structure formed by stacking the positive electrode sheet, the separator and the negative electrode sheet. The main body 21 may be a portion of the electrode assembly 2 corresponding to the region where the electrode sheet is coated with an active material layer. The positive electrode ear may be a portion of the positive electrode sheet that is not coated with a positive electrode active material layer, and the negative electrode ear may be a portion of the negative electrode sheet that is not coated with a negative electrode active material layer.

[0149] L=L1×N means that along the first direction X, the main body 21 is evenly divided into a plurality of sub-areas 211, the number of the sub-areas 211 is equal to the number of the pressure relief mechanisms 3 arranged on the first wall 111 along the first direction X, and the lengths of all the sub-areas 211 are equal. Taking N=2 as an example, there are two sub-areas 211 in the main body 21, and the length of each sub-area 211 along the first direction X is L1=L / 2.

[0150] L can be any point value among 400mm, 500mm, 600mm, 700mm, 800mm, 900mm, 1000mm, etc., or a range value between any two of them.

[0151] Along the thickness direction Z of the first wall portion, the projection of each pressure relief mechanism 3 is correspondingly located in a sub-region 211 . In other words, when observing along the thickness direction Z of the first wall portion, each pressure relief mechanism 3 is blocked by a corresponding sub-region 211 .

[0152] The thickness direction Z of the first wall portion may be perpendicular to the first direction X, or may be arranged at an acute angle or an obtuse angle. Figure 5 In the embodiment, the thickness direction Z of the first wall portion is perpendicular to the first direction X.

[0153] For a general battery cell 10, when the length of the main body 21 is greater than or equal to 400 mm, the large capacity requirement of the battery cell 10 can be met, but the pressure relief capacity is poor, and it is easy to cause untimely pressure relief. In this embodiment, the projection of each pressure relief mechanism 3 along the thickness direction Z of the first wall portion corresponds to a sub-region 211, so that each sub-region 211 can correspond to a pressure relief mechanism 3 on the shell 1, and each pressure relief mechanism 3 can discharge the emission medium generated by the thermal runaway of a corresponding sub-region 211. If any sub-region 211 of the main body 21 has thermal runaway, the emission medium generated by the thermal runaway can be quickly discharged through the corresponding pressure relief mechanism 3, which can effectively improve the timeliness of the pressure relief of the battery cell 10, and thus improve the reliability of the battery cell 10.

[0154] In some embodiments, the first wall portion 111 supports the main body portion 21 along the gravity direction.

[0155] The thickness direction Z of the first wall portion may be parallel to the gravity direction. The first wall portion 111 is a wall portion of the housing 1 supporting the main body portion 21 along the gravity direction, and the first wall portion 111 bears the gravity of the main body portion 21. The first wall portion 111 may directly contact the main body portion 21 to support the main body portion 21, or an intermediate piece may 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 piece, and the intermediate piece may be an insulating piece provided between the first wall portion 111 and the main body portion 21.

[0156] In this embodiment, the first wall portion 111 supports the main body portion 21 in the direction of gravity, and the discharge inside the housing 1 can be discharged from the bottom of the housing 1. Since the first wall portion 111 is the wall portion of the housing 1 that supports the main body portion 21, the first wall portion 111 is pressed by the main body portion 21, and the area inside the housing 1 near the first wall portion 111 is more likely to be blocked and suffocated, which is not conducive to the discharge of the discharge 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 discharge medium inside the housing 1 near the first wall portion 111, thereby improving the reliability of the battery cell 10.

[0157] In some embodiments, please refer to Figure 5 The housing 1 further includes a second wall portion 112. The first wall portion 111 and the second wall portion 112 are arranged opposite to each other along the thickness direction Z of the first wall portion. The first wall portion 111 supports the main body portion 21 along the gravity direction. 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 space located at both ends of the main body portion 21 along the first direction X inside the housing 1.

[0158] The first wall portion 111 and the second wall portion 112 are two opposite wall portions of the housing 1 . The thicknesses of the first wall portion 111 and the second wall portion 112 may be equal or different.

[0159] The 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 housing 1 are respectively the first space 14 and the second space 15. The channel gap 13 connects the first space 14 and the second space 15. When the battery cell 10 thermally runs away, 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.

[0160] In this embodiment, the channel gap 13 can connect the spaces inside the shell 1 at both ends of the main body 21 along the first direction X. When a sub-area 211 located at one end of the main body 21 undergoes 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-area 211, and can also flow to the other end of the main body 21 through the channel gap 13 and be discharged through the pressure relief mechanism 3 corresponding to the sub-area 211 at the other end of the main body 21, so that the discharge medium inside the battery cell 10 can be quickly discharged, thereby improving the timeliness of the pressure relief of the battery cell 10.

[0161] In some embodiments, please refer to Figure 6 , Figure 6 for Figure 5 The cross-sectional view of the housing 1 shown is cut along the YZ plane, and the housing 1 further includes a third wall portion 113 and a fourth wall portion 114, which are arranged opposite to each other along the second direction Y, and the first wall portion 111 connects the third wall portion 113 and the fourth wall portion 114, and a plane formed by the intersection of the thickness direction Z of the first wall portion and the first direction X intersects the second direction Y. The thickness of the third wall portion 113 and the thickness of the fourth wall portion 114 are both less than the thickness of the first wall portion 111.

[0162] A plane formed by the intersection of the thickness direction Z of the first wall and the first direction X intersects the second direction Y, so that the thickness direction Z of the first wall, the first direction X and the second direction Y are not coplanar.

[0163] The thickness of the first wall portion 111 may be equal to the thickness of the second wall portion 112 ; the thickness of the first wall portion 111 may be different from the thickness of the second wall portion 112 , for example, the thickness of the first wall portion 111 is greater than the thickness of the second wall portion 112 .

[0164] 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.

[0165] In this embodiment, the thickness of the third wall portion 113 and the thickness of the fourth wall portion 114 are both smaller than the thickness of the first wall portion 111, which can increase the thickness of the first wall portion 111, improve the deformation resistance of the first wall portion 111, and reduce the risk of excessive deformation of the first wall portion 111 due to expansion of the battery cell 10, thereby reducing the impact of the deformation of the first wall portion 111 on the pressure relief mechanism 3, reducing the risk of the pressure relief mechanism 3 starting to relieve pressure prematurely, and increasing the service life of the pressure relief mechanism 3.

[0166] In some embodiments, the sum of the predetermined pressure relief areas of N pressure relief mechanisms 3 is S1. Along the thickness direction Z of the first wall portion, the first wall portion 111 has a first outer surface 1113 away from the main body portion 21. The area of ​​the first outer surface 1113 is S2, and 0.05≤S1 / S2≤0.55.

[0167] The predetermined pressure relief areas of the N pressure relief mechanisms 3 may be equal, or the predetermined pressure relief areas of at least two pressure relief mechanisms 3 may be different. The predetermined pressure relief area of ​​the pressure relief mechanism 3 is the maximum area that the pressure relief mechanism 3 is expected to be able to open.

[0168] Taking the first wall portion 111 as an example, two pressure relief mechanisms 3 arranged along the first direction X are provided. It can be understood that N=2, and the predetermined pressure relief area of ​​one pressure relief mechanism 3 is S 11 , the predetermined pressure relief area of ​​the other pressure relief mechanism 3 is S 12 , S1=S 11 +S 12 The area of ​​the first outer surface 1113 is the area of ​​the region defined by the outer edge of the first outer surface 1113 .

[0169] As an example, the first wall portion 111 is a rectangular wall portion, and the first outer surface 1113 of the first wall portion 111 is a rectangle. The length and width of the first outer surface 1113 of the first wall portion 111 are measured, and the length and width of the first outer surface 1113 are multiplied to calculate the area of ​​the first outer surface 1113 of the first wall portion 111. 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 can be connected to the outer surface of the third wall portion 113 through a rounded surface, and the first outer surface 1113 of the first wall portion 111 can be connected to the outer surface of the fourth wall portion 114 through another rounded surface.

[0170] In this embodiment, S1 / S2 can be any point value among 0.05, 0.1, 0.13, 0.15, 0.18, 0.2, 0.23, 0.25, 0.28, 0.3, 0.33, 0.35, 0.38, 0.4, 0.43, 0.45, 0.48, 0.5, 0.53, 0.55, etc., or a range value between any two of them.

[0171] In this embodiment, S1 / S2≥0.05, so that the total pressure relief area of ​​the N pressure relief mechanisms 3 is larger, which is beneficial to improving the pressure relief rate of the battery cell 10 and improving the timeliness of the pressure relief of the battery cell 10; S1 / S2≤0.55 is beneficial to improving the strength of the first wall portion 111.

[0172] In some embodiments, 0.15≤S1 / S2≤0.35.

[0173] In this embodiment, S1 / S2 can be any point value among 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, etc., or a range value between any two of them.

[0174] In some embodiments, the predetermined pressure relief areas of the N pressure relief mechanisms 3 are equal.

[0175] Taking the example that the first wall portion 111 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.

[0176] In this embodiment, the predetermined pressure relief areas of the N pressure relief mechanisms 3 are equal, so that the pressure relief capacities of all the pressure relief mechanisms 3 on the first wall portion 111 are substantially consistent, and the difficulty of forming each pressure relief mechanism 3 can be reduced.

[0177] In some embodiments, please refer to Figure 7 , Figure 7 for Figure 5 The battery cell 10 is shown in the A-direction view. The housing 1 includes a first half area 16 and a second half area 17. Along the first direction X, the portion from the middle section W of the housing 1 to one end of the housing 1 is the first half area 16, and the portion from the middle section W of the housing 1 to the other end of the housing 1 is the second half area 17. Both the first half area 16 and the second half area 17 are provided with at least one pressure relief mechanism 3. The first direction X is perpendicular to the middle section W.

[0178] Along the first direction X, the shell 1 has two opposite end faces, the distances from the middle section W of the shell 1 to the two end faces are equal, the portion of the shell 1 from one end face to the middle section W is the first half section 16, and the portion of the shell 1 from the other end face to the middle section W is the second half section 17. In the embodiment of the shell 11 being a hollow structure with an opening formed at one end along the first direction X, the surface of the end cover 12 facing the outside of the shell 1 may be one end face of the shell 1, and the surface of the wall portion of the shell 11 opposite to the end cover 12 facing the outside of the shell 1 may be the other end face of the shell 1. In the embodiment of the shell 11 being a hollow structure with openings formed at opposite ends along the first direction X, the surface of one end cover 12 facing the outside of the shell 1 may be one end face of the shell 1, and the surface of the other end cover 12 facing the outside of the shell 1 may be the other end face of the shell 1.

[0179] The first half area 16 may be provided with one pressure relief mechanism 3 or multiple pressure relief mechanisms 3 ; the second half area 17 may be provided with one pressure relief mechanism 3 or multiple pressure relief mechanisms 3 .

[0180] When the battery cell 10 is in thermal runaway, pressure relief can be performed through the pressure relief mechanism 3 of the first half zone 16 and the pressure relief mechanism 3 of the second half zone 17, so that the emission medium in the first half zone 16 in the outer shell 1 can be discharged more quickly through the pressure relief mechanism 3 of the first half zone 16, and the emission medium in the second half zone 17 in the outer shell 1 can be discharged more quickly through the pressure relief mechanism 3 of the second half zone 17, thereby improving the timeliness of pressure relief of the battery cell 10.

[0181] In some embodiments, only two pressure relief mechanisms 3 are disposed on the first wall portion 111 , and the two pressure relief mechanisms 3 are located in the first half area 16 and the second half area 17 , respectively.

[0182] It can be understood that, among the two pressure relief mechanisms 3 , one pressure relief mechanism 3 is disposed at the portion of the first wall portion 111 located in the first half zone 16 , and the other pressure relief mechanism 3 is disposed at the portion of the first wall portion 111 located in the second half zone 17 .

[0183] In this embodiment, only two pressure relief mechanisms 3 are provided on the first wall portion 111, so that there are not too many pressure relief mechanisms 3 on the first wall portion 111. While achieving rapid pressure relief of the battery cell 10, the manufacturing cost of the battery cell 10 is reduced, which has better economy.

[0184] In some embodiments, please refer to Figure 7 The pressure relief mechanism 3 is provided with a notched groove 31 , and along the first direction X, the length of the housing 1 is L2 , and the minimum distance between the notched grooves 31 of two adjacent pressure relief mechanisms 3 is L3 , L2 > L, L3 / L2 ≥ 1 / 6.

[0185] The maximum distance between the end faces at both ends of the housing 1 along the first direction X is the length of the housing 1. If the two end faces of the housing 1 are planes, the length of the housing 1 along the first direction X is measured with the two end faces as a reference; if one or both end faces of the housing 1 are formed with convex or concave portions, the length of the housing 1 along the first direction X is measured with the plane area of ​​the end face as a reference. The distance between the two closest positions of the notched grooves 31 of two adjacent pressure relief mechanisms 3 is the minimum distance between the notched grooves 31 of two adjacent pressure relief mechanisms 3.

[0186] L3 / L2 can be any point value among 1 / 6, 1 / 5, 1 / 4, 1 / 3, 1 / 2, 2 / 3, etc., or any range value between two points.

[0187] In this embodiment, L3 / L2≥1 / 6, so that the minimum distance between the notched grooves of two adjacent pressure relief mechanisms 3 is not too small, so that each pressure relief mechanism 3 can correspond to a larger area of ​​the main body 21, fully utilizing each pressure relief mechanism 3 and improving the timeliness of pressure relief of the battery cell 10.

[0188] In some embodiments, L3 / L2≥1 / 4.

[0189] In this embodiment, L3 / L2 can be any point value among 1 / 4, 1 / 3, 5 / 12, 1 / 2, 7 / 12, 2 / 3, etc., or a range value between any two of them.

[0190] In this embodiment, the distance between two adjacent pressure relief mechanisms 3 is further increased. If only two pressure relief mechanisms 3 are provided on the first wall portion 111, the two pressure relief mechanisms 3 are closer to the ends of the shell 11 along the first direction X, which is more conducive to the rapid discharge of the discharge medium located at the two ends of the main body 21 in the shell 11.

[0191] In some embodiments, L2 ≥ 500 mm; and / or, L3 ≥ 300 mm.

[0192] L2 can be any point value of 500mm, 550mm, 600mm, 650mm, 750mm, 800mm, etc., or a range value between any two of them. L3 can be any point value of 300mm, 330mm, 350mm, 380mm, 400mm, 430mm, 450mm, etc., or a range value between any two of them.

[0193] L2≥500mm, the housing 1 is relatively large in the first direction X, and 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, and the discharge medium in a 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.

[0194] In some embodiments, please refer to Figure 7 Along the first direction X, the length of the housing 1 is L2, the pressure relief mechanism 3 is provided with a notched groove 31, and the sum of the maximum spans of the notched grooves 31 of the N pressure relief mechanisms 3 along the first direction X is D1, 0.2≤D1 / L2≤0.6.

[0195] The maximum span of the notched groove 31 along the first direction X is the distance between the two farthest positions of the notched groove 31 along the first direction X. The maximum spans of the notched grooves 31 of the N pressure relief mechanisms 3 on the first wall portion 111 along the first direction X may be equal, or the maximum spans of the notched grooves 31 of at least two pressure relief mechanisms 3 on the first wall portion 111 along the first direction X may be different. The notched groove 31 may be a groove extending along a closed trajectory, which may be circular, rectangular, etc.; the notched groove 31 may also be a groove along a non-closed trajectory, which may be linear, arc-shaped, U-shaped, H-shaped, V-shaped, L-shaped, X-shaped, Y-shaped, etc. The notched groove 31 may be located on the inner side of the pressure relief mechanism 3 (the side of the pressure relief mechanism 3 facing the main body 21 along the thickness direction Z of the first wall portion), or on the outer side of the pressure relief mechanism 3 (the side of the pressure relief mechanism 3 facing away from the main body 21 along the thickness direction Z of the first wall portion). It should be noted that, among the multiple pressure relief mechanisms 3 of the first wall portion 111, the notched grooves 31 of some of the pressure relief mechanisms 3 may be located on the inner side of the pressure relief mechanisms 3, and the notched grooves 31 of other parts of the pressure relief mechanisms 3 may be located on the outer side of the pressure relief mechanisms 3; or the notched grooves 31 of all the pressure relief mechanisms 3 may be located on the inner side of the pressure relief mechanisms 3; or the notched grooves 31 of all the pressure relief mechanisms 3 may be located on the outer side of the pressure relief mechanisms 3.

[0196] For example, when only two pressure relief mechanisms 3 are provided on the first wall portion 111 , the maximum span of the notched groove 31 of one pressure relief mechanism 3 along the first direction X is D2 , and the maximum span of the notched groove 31 of the other pressure relief mechanism 3 along the first direction X is D3 , and D1 = D2 + D3 .

[0197] In this embodiment, D1 / L2 can be any point value among 0.2, 0.23, 0.25, 0.28, 0.3, 0.33, 0.35, 0.38, 0.4, 0.43, 0.45, 0.48, 0.5, 0.53, 0.55, 0.58, 0.6, etc., or a range value between any two of them.

[0198] In this embodiment, D1 / L2≥0.2, so that the sum of the maximum spans of the notched grooves 31 of the multiple pressure relief mechanisms 3 on the first wall portion 111 along the first direction X is large, which can increase the total pressure relief area of ​​the multiple pressure relief mechanisms 3 on the first wall portion 111, which is beneficial to improving the pressure relief rate of the battery cell 10. D1 / L2≤0.6, so that the sum of the maximum spans of the notched grooves 31 of the multiple 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.

[0199] In some embodiments, please refer to Figure 8 , Figure 8 for Figure 6 The partial enlarged view of the housing 1 is shown. The pressure relief mechanism 3 is provided with a notch groove 31 , and a weak portion 32 is formed in the region where the notch groove 31 is provided. The weak portion 32 is configured to be able to rupture to release the pressure inside the battery cell 10 .

[0200] The weak portion 32 is a portion of the pressure relief mechanism 3 that is lower in strength than other regions. After the notched groove 31 is provided on the pressure relief mechanism 3, the remaining portion of the pressure relief mechanism 3 corresponding to the notched groove 31 is the weak portion 32, and the bottom wall of the notched groove 31 may be the weak portion 32. When the battery cell 10 is in thermal runaway, the pressure relief mechanism 3 may be ruptured at the weak portion 32 to release the pressure inside the battery cell 10.

[0201] In this embodiment, a weak portion 32 is formed in the corresponding area of ​​the pressure relief mechanism 3 by providing a notch groove 31. The method of forming the weak portion 32 is simple. The weak portion 32 is a weaker area in the pressure relief mechanism 3. The weak portion 32 is more easily destroyed when the battery cell 10 is in thermal runaway, so as to release pressure in time.

[0202] In some embodiments, please refer to Figure 8 , along the thickness direction Z of the first wall portion, the notch of the notch groove 31 is away from the main body portion 21 ( Figure 8 not shown).

[0203] As an example, the notched groove 31 is disposed on the outer side of the pressure relief mechanism 3 so that the notch of the notched groove 31 faces the main body 21 .

[0204] In this embodiment, the notch of the notched groove 31 is away from the main body 21. If the pressure relief mechanism 3 and the first wall portion 111 are integrally formed, it is convenient to process the notched groove 31 on the first wall portion 111. If the pressure relief mechanism 3 and the first wall portion 111 are separately arranged, it is convenient to install the pressure relief mechanism 3 on the first wall portion 111.

[0205] In some other embodiments, along the thickness direction Z of the first wall portion, the notch of the notch groove 31 faces the main body portion 21 .

[0206] As an example, the notched groove 31 is disposed on the inner side of the pressure relief mechanism 3 so that the notch of the notched groove 31 faces the main body 21 .

[0207] In this embodiment, the notch of the notch groove 31 faces the main body 21 , so that the weak portion 32 is not easily torn when the first wall portion 111 is deformed due to the expansion of the battery cell 10 , thereby improving the long-term reliability of the pressure relief mechanism 3 .

[0208] In some embodiments, the pressure relief mechanism 3 includes a pressure relief area 33 , and the pressure relief area 33 is configured to be opened when the weak portion 32 is broken.

[0209] The pressure relief area 33 is a portion of the pressure relief mechanism 3 that can be opened after the weak portion 32 is split. The pressure relief area 33 can be set along the edge of the weak portion 32. When the pressure is released, the pressure relief area 33 can be opened by turning over or detaching. The area of ​​the pressure relief area 33 is the predetermined pressure relief area of ​​the pressure relief mechanism 3.

[0210] In this embodiment, the notched groove 31 can be a groove extending along a closed trajectory; the notched groove 31 can also be a groove extending along a non-closed trajectory, and the non-closed trajectory can be arc-shaped, U-shaped, H-shaped, V-shaped, L-shaped, Y-shaped, X-shaped, etc.

[0211] In this embodiment, the weak portion 32 defines a pressure relief area 33 . During pressure relief, the pressure relief area 33 can be opened with the weak portion 32 as a boundary, thereby increasing the pressure relief area of ​​the pressure relief mechanism 3 .

[0212] In some embodiments, please refer to Fig. 9 , Fig. 9 The partial view of the first wall portion 111 provided in some embodiments of the present application. The notched groove 31 is a groove extending along a closed track, and the notched groove 31 is arranged around the pressure relief area 33 .

[0213] It can be understood that the notched groove 31 is an annular groove arranged around the pressure relief area 33 .

[0214] As an example, Fig. 9 As shown, the notched groove 31 includes two first arc segments 311 and two first straight segments 312, the two first straight segments 312 are arranged in parallel, one first arc segment 311, one first straight segment 312, another first arc segment 311 and another first straight segment 312 are connected end to end, and the center angles of the two first arc segments 311 are both 180°. The area of ​​the pressure relief zone 33 (the predetermined pressure relief area of ​​the pressure relief mechanism 3) is S 13 , S 13 =a×b+π×a 2 / 4. Wherein, a is the distance between the inner side of one first straight line segment 312 and the inner side of another first straight line segment 312, and b is the length of the first straight line segment 312. Both a and b can be measured on the surface where the notch of the notch groove 31 is located.

[0215] In this embodiment, the notched groove 31 is a groove extending along a closed trajectory. During the pressure relief process, after the pressure relief mechanism 3 is split along the notched groove 31 , the pressure relief area 33 can be separated from the first wall portion 111 , thereby increasing the pressure relief area and improving the pressure relief rate of the battery cell 10 .

[0216] In some embodiments, please refer to Fig.10 and Fig.11 , Fig.10 Partial views of the first wall portion 111 provided for some other embodiments of the present application; Fig.11 The partial view of the first wall portion 111 provided for some other embodiments of the present application. The notched groove 31 is a groove extending along a non-closed track.

[0217] As an example, Fig.10 As shown, the notched groove 31 is an H-shaped groove, and the notched groove 31 includes a second straight line segment 313 and two third straight line segments 314. The two third straight line segments 314 are arranged in parallel, one end of the second straight line segment 313 is connected to the midpoint of one third straight line segment 314, and the other end of the second straight line segment 313 is connected to the midpoint of another third straight line segment 314. The area of ​​the pressure relief zone 33 (the predetermined pressure relief area of ​​the pressure relief mechanism 3) is S 13 , S 13 =2×c×d. Wherein, 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 the end. Both c and d can be measured on the surface where the notch of the notch groove 31 is located.

[0218] As an example, Fig.11As shown, the notched groove 31 is a double Y-shaped groove, and the notched groove 31 includes a fourth straight line segment 315 and a fifth straight line segment 316. Both ends of the fourth straight line segment 315 are connected to two fifth straight line segments 316 set at a non-zero angle. Along the length direction of the fourth straight line segment 315, the two fifth straight line segments 316 located at one end of the fourth straight line segment 315 are symmetrically arranged with the two fifth straight line segments 316 located at the other end of the fourth straight line segment 315. Along the width direction of the fourth straight line segment 315, the two fifth straight line segments 316 located on one side of the fourth straight line segment 315 are symmetrically arranged with the two fifth straight line segments 316 located on the other side of the fourth straight line segment 315. Along the length direction of the fourth straight line segment 315, the line connecting the free ends of the two fifth straight line segments 316 is a first line 317; along the width direction of the fourth straight line segment 315, the line connecting the free ends of the two fifth straight line segments 316 is a second line 318. The area of ​​the pressure relief zone 33 (the predetermined pressure relief area of ​​the pressure relief mechanism 3) is S 13 , S 13 =(f+g)×e+k×h. Wherein, f is the length of the fourth straight line segment 315, g is the length of the first line 317, e is the distance between the first line 317 and the side of the fourth straight line segment 315 facing the first line 317, k is the length of the second line 318, and h is the distance between the connection position of the two fifth straight line segments 316 located at one end of the fourth straight line segment 315 facing the second line 318 and the second line 318. f, g, e, k and h can all be measured on the surface where the notch of the notch groove 31 is located.

[0219] In some embodiments, please refer to Figure 6 and Figure 8 The pressure relief mechanism 3 and the first wall portion 111 are integrally formed.

[0220] In the embodiment where the pressure relief mechanism 3 is provided with a notched groove 31 , the pressure relief mechanism 3 may be composed of a weak portion 32 and a pressure relief area 33 , and the weak portion 32 , the pressure relief area 33 and the first wall portion 111 may be integrally formed, thereby achieving integral formation of the pressure relief mechanism 3 and the first wall portion 111 .

[0221] As an example, the housing 1 may include a first wall portion 111, a second wall portion 112, a third wall portion 113, and a fourth wall portion 114. The first wall portion 111 and the second wall portion 112 are arranged opposite to 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 to 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 in sequence, and the thickness direction Z of the first wall portion, the first direction X, and the second direction Y are perpendicular to each other. The third wall portion 113 and the fourth wall portion 114 may be the wall portions with the largest outer surface area in the housing 1.

[0222] In this embodiment, the pressure relief mechanism 3 and the first wall portion 111 are integrally formed, the reliability of the pressure relief mechanism 3 is higher, the connection process between the pressure relief mechanism 3 and the first wall portion 111 is omitted, and the production cost of the battery cell 10 can be reduced.

[0223] In some embodiments, please refer to Fig.12 and Fig.13 , Fig.12 An exploded view of a battery cell 10 provided in some other embodiments of the present application; Fig.13 for Fig.12 The cross-sectional view of the battery cell 10 is shown. The pressure relief mechanism 3 is disposed separately from the first wall portion 111 . The first wall portion 111 is provided with a pressure relief hole 1111 . The pressure relief mechanism 3 is mounted on the first wall portion 111 and covers the pressure relief hole 1111 .

[0224] The pressure relief mechanism 3 and the housing 1 are two separate components, which are separately molded and then installed together. The pressure relief mechanism 3 can be a component such as an explosion-proof plate, an explosion-proof valve, a safety valve, etc. The pressure relief mechanism 3 can be installed on the first wall portion 111 by bonding, welding, etc. When the battery cell 10 is thermally runaway, the pressure relief mechanism 3 opens at least part of the pressure relief hole 1111, and the discharge medium inside the battery cell 10 is discharged through the pressure relief hole 1111 to release the pressure inside the battery cell 10.

[0225] The pressure relief mechanism 3 covers the pressure relief hole 1111, and the pressure relief mechanism 3 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 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 can be located on the side of the pressure relief hole 1111 facing away from the main body 21 along the thickness direction Z of the first wall. If the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 facing the main body 21 along the thickness direction Z of the first wall, the pressure relief mechanism 3 separates the pressure relief hole 1111 from the internal space of the shell 1. When the battery cell 10 is in thermal runaway, the pressure relief mechanism 3 is destroyed, the pressure relief hole 1111 is connected to the internal space of the shell 1, and the discharge medium inside the shell 1 can be discharged through the pressure relief hole 1111. If the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 away from the main body 21 along the thickness direction Z of the first wall portion, the pressure relief hole 1111 is connected with the internal space of the outer shell 1, and the pressure relief mechanism 3 separates the pressure relief hole 1111 from the external space of the outer shell 1. When the battery cell 10 thermally runs away, the pressure relief mechanism 3 is destroyed, and the pressure relief hole 1111 connects the internal space of the outer shell 1 with the external space of the outer shell 1, and the discharge medium inside the outer shell 1 can be discharged through the pressure relief hole 1111.

[0226] As an example, Fig.12 and Fig.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 body whose strength in at least a part of the area is less than that of the first wall portion 111, and the explosion-proof plate covers the pressure relief hole 1111. When the battery cell 10 is in thermal runaway, the explosion-proof plate is at least partially destroyed, thereby opening at least part of the pressure relief hole 1111 to release the pressure inside the battery cell 10.

[0227] In this embodiment, the pressure relief mechanism 3 is a component independent of the housing 1 , and the pressure relief mechanism 3 and the housing 1 can be produced and assembled separately, with low production difficulty and high efficiency.

[0228] In some embodiments, please refer to Fig.14 and Fig.15 , Fig.14 for Fig.13 A partial enlarged view of the battery cell 10 is shown; Fig.15 for Fig.14 1 is a cross-sectional view of the first wall portion 111 shown in FIG. The first wall portion 111 is provided with a first groove 1112, the first groove 1112 includes a groove side surface 1112a and a first groove bottom surface 1112b, the groove side surface 1112a is arranged around the first groove bottom surface 1112b, the pressure relief hole 1111 is arranged on the first groove bottom surface 1112b, and the pressure relief mechanism 3 is arranged in the first groove 1112 and abuts against the first groove bottom surface 1112b. A gap 5 is formed between the groove side surface 1112a and the pressure relief mechanism 3 along at least a portion of the circumference of the first groove 1112.

[0229] The first groove 1112 can be formed on the first wall portion 111 in a variety of ways, such as stamping, milling, laser etching, etc. The groove side 1112a is a closed structure extending along the circumference of the first groove 1112. Along the depth direction of the first groove 1112, the notch of the first groove 1112 is arranged opposite to the first groove bottom surface 1112b, and the depth direction of the first groove 1112 can be parallel to the thickness direction Z of the first wall portion. The first groove 1112 can be a polygonal groove, a circular groove, etc. If the first groove 1112 is a polygonal groove, the cross-section of the groove side 1112a is a polygon, and the first groove bottom surface 1112b can be a polygon; if the first groove 1112 is circular, the cross-section of the groove side 1112a is circular, and the first groove bottom surface 1112b can be circular. Among them, the cross-section of the groove side 1112a is perpendicular to the depth direction of the first groove 1112. The groove side surface 1112a may include multiple side surfaces, and along the circumference of the first groove 1112, the multiple side surfaces are connected end to end in sequence. The side surface may be a surface parallel to the thickness direction Z of the first wall portion, and the side surface may be perpendicular to the first groove bottom surface 1112b; the side surface may also be an inclined surface arranged at an obtuse angle to the first groove bottom surface 1112b. Of course, the side surface may be a plane or an arc surface. If the side surface is an arc surface, the side surface may be an arc surface whose center line is parallel to the thickness direction Z of the first wall portion, or an arc surface whose center line is perpendicular to the thickness direction Z of the first wall portion.

[0230] The pressure relief mechanism 3 is arranged in the groove. The pressure relief mechanism 3 can be completely located in the first groove 1112, or a part of it can be located in the first groove 1112 and a part of it can be located outside the first groove 1112. There are many ways to connect the pressure relief mechanism 3 and the first wall portion 111, such as welding, bonding, etc. The pressure relief mechanism 3 can directly contact the bottom surface 1112b of the first groove, so that the pressure relief mechanism 3 directly abuts against the bottom surface 1112b of the first groove; the pressure relief mechanism 3 can also indirectly abut against the bottom surface 1112b of the first groove through an intermediate piece. For example, the pressure relief mechanism 3 is welded to the bottom wall 1112c of the first groove 1112, so that the pressure relief mechanism 3 contacts the bottom surface 1112b of the first groove, and the pressure relief mechanism 3 directly abuts against the bottom surface 1112b of the first groove; for another example, the pressure relief mechanism 3 is bonded to the bottom wall 1112c of the first groove 1112 through an adhesive layer, and the pressure relief mechanism 3 indirectly abuts against the bottom surface 1112b of the first groove through the adhesive layer.

[0231] The circumference of the first groove 1112 surrounds the depth direction of the first groove 1112, and the circumference of the notch of the first groove 1112 is the circumference of the first groove 1112. A gap 5 may be formed between the groove side surface 1112a along a part of the circumference of the first groove 1112 and the pressure relief mechanism 3, or a gap 5 may be formed between the groove side surface 1112a along the entire 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 along the circumference of the pressure relief mechanism 3. If a gap 5 is formed between a portion of the groove side surface 1112a along the circumference of the first groove 1112 and the outer circumferential surface 34 of the pressure relief mechanism 3, and no gap 5 is formed between the other portion of the groove side surface 1112a along the circumference of the first groove 1112 and the outer circumferential surface 34 of the pressure relief mechanism 3, then a gap 5 is formed between a portion of the groove side surface 1112a along the circumference of the first groove 1112 and the pressure relief mechanism 3, and the gap 5 is a non-closed structure extending along the circumference of the first groove 1112; if a gap 5 is formed between the groove side surface 1112a and the outer circumferential surface 34 of the pressure relief mechanism 3 along the entire circumference of the first groove 1112, then a gap 5 is formed between the groove side surface 1112a and the pressure relief mechanism 3 along the entire circumference of the first groove 1112, and the gap 5 is a closed structure extending along the circumference of the first groove 1112, that is, the gap 5 is an annular gap.

[0232] As an example, the pressure relief mechanism 3 is provided with a notched groove 31 to form a corresponding weak portion 32 ( Fig.14 and Fig.15 not shown).

[0233] When the first wall portion 111 is deformed due to the expansion of the battery cell 10, the gap 5 between the pressure relief mechanism 3 and the groove side 1112a can provide a buffer space for the pressure relief mechanism 3, thereby reducing the risk of the groove side 1112a squeezing the pressure relief mechanism 3 and causing deformation of the pressure relief mechanism 3, thereby reducing the risk of the pressure relief mechanism 3 opening prematurely during normal use of the battery cell 10 and increasing the service life of the pressure relief mechanism 3.

[0234] In some embodiments, please refer to Fig.16 and Fig.17 , Fig.16 An assembly diagram of the pressure relief mechanism 3 and the first wall portion 111 provided in some embodiments of the present application; Fig.17 for Fig.16 The schematic diagram of the structure of the first wall portion 111 is shown. The groove side surface 1112a includes a first area 1112d with a gap 5 formed with the pressure relief mechanism 3. Along the circumference of the first groove 1112, the length of the first area 1112d is L4, and the circumference of the groove side surface 1112a is L5, which satisfies: 0.2≤L4 / L5≤1.

[0235] The length of the first area 1112d is the total length of the portion of the groove side surface 1112a that forms the gap 5 with the pressure relief mechanism 3 along the circumferential direction of the first groove 1112. When measuring the length of the first area 1112d and the circumference of the groove side surface 1112a, the measurement can be performed along the edge of the groove side surface 1112a located at the notch position of the first groove 1112.

[0236] L4 / L5 can be any point value of 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, etc., or a range value between any two of them.

[0237] As an example, the groove side surface 1112a includes two first side surfaces 1112e and two second side surfaces 1112f, the two first side surfaces 1112e are arranged oppositely along the second direction Y, the two second side surfaces 1112f are arranged oppositely along the first direction X, and 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. 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, a gap 5 is formed between the two first side surfaces 1112e and the pressure relief mechanism 3, and only a portion of each second side surface 1112f forms a gap 5 with the pressure relief mechanism 3. It can be understood that the parts of the two second side surfaces 1112f and the pressure relief mechanism 3 forming the gap 5 and the two first side surfaces 1112e constitute the first area 1112d, and along the circumference of the first groove 1112, the total length of the parts of the two second side surfaces 1112f and the pressure relief mechanism 3 forming the gap 5 and the two first side surfaces 1112e is the length of the first area 1112d, and the total length of the two first side surfaces 1112e and the two second side surfaces 1112f is the circumference of the groove side surface 1112a.

[0238] In this embodiment, 0.2≤L4 / L5≤1, so that a gap 5 is formed between the longer part of the groove side 1112a in the circumferential direction and the pressure relief mechanism 3, reducing the extrusion range of the groove side 1112a on the pressure relief mechanism 3 when the first wall portion 111 is deformed, and further reducing the risk of the pressure relief mechanism 3 opening prematurely during normal use of the battery cell 10.

[0239] In some embodiments, please refer to Fig.18 , Fig.18 The assembly diagram of the pressure relief mechanism 3 and the first wall portion 111 provided in some other embodiments of the present application. A gap 5 is formed between the groove side surface 1112a and the pressure relief mechanism 3 along the entire circumference of the first groove 1112.

[0240] It can be understood that the gap 5 formed between the groove side surface 1112a and the outer peripheral surface 34 of the pressure relief mechanism 3 is an annular gap extending along the circumference of the first groove 1112. In this embodiment, the first area 1112d is the groove side surface 1112a, and L4 / L5=1.

[0241] In this embodiment, there is a gap 5 around the entire circumference of the groove side 1112a and the pressure relief mechanism 3. The gap 5 is an annular structure surrounding the pressure relief mechanism 3, further reducing the squeezing effect of the groove side 1112a on the pressure relief mechanism 3 when the first wall portion 111 is deformed, and further reducing the risk of the pressure relief mechanism 3 opening prematurely during normal use of the battery cell 10.

[0242] In some embodiments, please refer to Fig.19 , Fig.19 Partial views of battery cells 10 provided in some other embodiments of the present application. The pressure relief mechanism 3 is welded to the groove bottom wall 1112 c of the first groove 1112 to form a first weld mark 6 .

[0243] The groove bottom wall 1112c of the first groove 1112 is a solid part of the pressure relief mechanism 3 located below the first groove bottom surface 1112b along the depth direction of the first groove 1112 and having a thickness. The first weld mark 6 is a welding area formed between the pressure relief mechanism 3 and the groove bottom wall 1112c, and the first weld mark 6 can be formed by melting a part of the pressure relief mechanism 3 and a part of the groove bottom wall 1112c together. The weld mark can be an annular structure extending along the circumference of the pressure relief mechanism 3, or a multi-segment structure arranged at intervals along the circumference of the pressure relief mechanism 3, or a long strip structure extending along a straight track.

[0244] In this embodiment, the pressure relief mechanism 3 is welded to the groove bottom wall 1112 c of the first groove 1112 , so that the pressure relief mechanism 3 is fixed to the first wall portion 111 , thereby improving the connection strength between the pressure relief mechanism 3 and the first wall portion 111 .

[0245] In some embodiments, along the thickness direction Z of the first wall portion, the projection of the first welded portion 6 is entirely located on the pressure relief mechanism 3 .

[0246] Observing along the thickness direction Z of the first wall portion, the welded portion is entirely located within the region defined by the outer edge of the pressure relief mechanism 3, and the welded portion has no portion located outside the region defined by the outer edge of the pressure relief mechanism 3. The welded portion has a portion located at the pressure relief mechanism 3 and a portion located at the groove bottom wall 1112c.

[0247] In this embodiment, the pressure relief mechanism 3 can be welded to the groove bottom wall 1112c of the first groove 1112 by penetration welding. The welding method is simple, and the first welded portion 6 formed after welding can pass through the pressure relief mechanism 3 and be embedded in the groove bottom wall 1112c of the first groove 1112, which can improve the connection strength between the pressure relief mechanism 3 and the first wall portion 111. In addition, since the projection of the first welded portion 6 along the thickness direction Z of the first wall portion is located on the pressure relief mechanism 3, the first welded portion 6 does not protrude from the edge of the pressure relief mechanism 3, and the first welded portion 6 is not located in the gap 5 between the pressure relief mechanism 3 and the groove side surface 1112a, which reduces the risk of the groove side surface 1112a squeezing the pressure relief mechanism 3 through the first welded portion 6 when the first wall portion 111 is deformed.

[0248] In some embodiments, please refer to Fig.19 Along the thickness direction Z of the first wall portion, the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 away from the main body 21 .

[0249] It is understandable that, along the thickness direction Z of the first wall portion, the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 away from the inside of the housing 1. The side of the pressure relief hole 1111 away from the inside of the housing 1 is the side of the pressure relief hole 1111 facing the outside of the housing 1.

[0250] In this embodiment, the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 away from the main body 21 . The pressure relief mechanism 3 can be installed on the outside of the first wall 111 , making it more convenient to install the pressure relief mechanism 3 .

[0251] In some embodiments, the battery cell 10 further includes a protective member 7 . Along the thickness direction Z of the first wall portion, the protective member 7 is located on a side of the pressure relief mechanism 3 away from the main body 21 , and the protective member 7 covers the first groove 1112 .

[0252] Along the thickness direction Z of the first wall portion, the side of the pressure relief mechanism 3 away from the main body 21 is the outside of the pressure relief mechanism 3. The protective member 7 covers the first groove 1112, so that the notch of the first groove 1112 is blocked by the protective member 7, and along the thickness direction Z of the first wall portion, the projection of the notch of the first groove 1112 is all located on the protective member 7. The protective member 7 can be a flat plate structure, and the protective member 7 can be made of metal, such as copper, iron, aluminum, steel, aluminum alloy, etc. The protective member 7 can also be made of non-metallic materials, such as plastic, rubber, etc. The protective member 7 is fixed to the first wall portion 111, and the protective member 7 can be fixed to the first wall portion 111 by welding, bonding, etc.

[0253] In this embodiment, the protective member 7 can protect the pressure relief mechanism 3 and reduce the risk of foreign substances (impurities, electrolyte) entering the first groove 1112 and corroding the pressure relief mechanism 3.

[0254] In some embodiments, along the thickness direction Z of the first wall portion, the first wall portion 111 has a first outer surface 1113 that faces away from the main body portion 21, the first outer surface 1113 is provided with a second groove 1114, the first groove 1112 is arranged on the bottom surface of the second groove 1114, and the protective member 7 is at least partially accommodated in the second groove 1114.

[0255] The first outer surface 1113 of the first wall portion 111 may be the surface of the first wall portion 111 that is farthest from the main body portion 21 in the thickness direction. The bottom surface of the second groove 1114 may be the first surface 1115, the first groove 1112 is disposed on the first surface 1115, and the protective member 7 may abut against the first surface 1115 so that the protective member 7 covers the first groove 1112. The second groove 1114 may be a polygonal groove, a circular groove, etc. The protective member 7 may be partially accommodated in the second groove 1114, or may be completely located in the second groove 1114.

[0256] In this embodiment, the first wall portion 111 is provided with a second groove 1114, and the protective member 7 is at least partially located in the second groove 1114, which can reduce the height of the protective member 7 protruding from the first outer surface 1113 of the first wall portion 111 and reduce the space occupied by the protective member 7 outside the shell 1.

[0257] In some embodiments, please refer to Fig. 20 , Fig. 20 The partial view of the battery cell 10 provided in some embodiments of the present application is shown in FIG.

[0258] It can be understood that the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 facing the inside of the housing 1 .

[0259] In this embodiment, the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 facing the main body 21. The pressure relief mechanism 3 can be installed on the inner side of the first wall portion 111. The first wall portion 111 can protect the pressure relief mechanism 3 and reduce the risk of the first wall portion 111 being damaged by external components.

[0260] In some embodiments, the battery cell 10 further includes a protective member 7 . Along the thickness direction Z of the first wall portion, the protective member 7 is located on a side of the pressure relief hole 1111 away from the main body portion 21 and covers the pressure relief hole 1111 .

[0261] Along the thickness direction Z of the first wall portion, the side of the pressure relief hole 1111 away from the main body portion 21 is the side of the pressure relief hole 1111 facing the outside of the housing 1. Along the thickness direction Z of the first wall portion, the pressure relief mechanism 3 and the protective member 7 are respectively located on both sides of the pressure relief hole 1111, the pressure relief mechanism 3 is located on the side of the pressure relief hole 1111 facing the inside of the housing 1, and the protective member 7 is located on the side of the pressure relief hole 1111 away from the inside of the housing 1.

[0262] The protective member 7 covers the pressure relief hole 1111 , and the protective member 7 blocks the pressure relief hole 1111 . Along the thickness direction Z of the first wall portion, the projection of the hole wall surface of the pressure relief hole 1111 can be entirely located on the protective member 7 .

[0263] As an example, along the thickness direction Z of the first wall portion, a protrusion 1116 arranged around the pressure relief hole 1111 is formed on the side of the first wall portion 111 away from the electrode assembly 2 , and the protective member 7 is fixed to the protrusion 1116 to cover the pressure relief hole 1111 .

[0264] In this embodiment, the protective member 7 can protect the pressure relief mechanism 3 and reduce the risk of external substances (impurities, electrolyte) entering the pressure relief hole 1111 and corroding the pressure relief mechanism 3.

[0265] In some embodiments, please refer to Fig.21 and Fig. 22 , Fig.21 An exploded view of a housing 1 provided in some embodiments of the present application; Fig. 22 Exploded diagram of a housing 1 provided in some other embodiments of the present application. The housing 1 comprises a shell 11 and an end cover 12. The shell 11 is formed with an opening at at least one end along the first direction X, and the shell 11 comprises a first wall portion 111. The end cover 12 corresponds to the opening one by one, and the end cover 12 closes the opening.

[0266] The first wall portion 111 is formed on the housing 11, and the first wall portion 111 is at least a part of the housing 11. The housing 11 may be cylindrical, polygonal, or the like. In an embodiment in which the housing 11 is cylindrical, the entire cylindrical side wall of the housing 11 may be used as the first wall portion 111; in an embodiment in which the housing 11 is polygonal, one of the walls of the housing 11 may be used as the first wall portion 111. As an example, in Fig.21 and Fig. 22 In the embodiment, the shell 11 is in a rectangular parallelepiped shape, and one wall portion of the shell 11 is a first wall portion 111 .

[0267] exist Fig.21 In the illustrated embodiment, the housing 11 is a hollow structure with openings formed at both ends along the first direction X; Fig. 22 In the illustrated embodiment, the housing 11 is a hollow structure with an opening formed at one end along the first direction X.

[0268] When assembling the battery cell 10, the electrode assembly 2 can be first installed in the housing 11, and then the opening of the housing 11 can be closed by the end cover 12, so that the assembly of the battery cell 10 is 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 when the battery cell 10 is depressurized by the pressure relief mechanism 3 on the components outside the end cover 12, which can be a busbar component, a detection component, etc. electrically connected to the electrode terminal 4 on the end cover 12.

[0269] In some embodiments, please refer to Fig.21 , openings are formed at opposite ends of the shell 11 along the first direction X.

[0270] It can be understood that there are two end covers 12 in the housing 1 , and the two end covers 12 respectively close the two openings of the housing 11 .

[0271] As an example, along the first direction X, the main body 21 ( Fig.21 Both ends of the Fig.21 The two end caps 12 of the housing 1 are provided with electrode terminals 4 ( Fig.21 (not shown), along the first direction X, the electrode terminal 4 on one end cover 12 is electrically connected to the pole tab 22 at one end of the main body 21, and the electrode terminal 4 on the other end cover 12 is electrically connected to the pole tab 22 at the other end of the main body 21.

[0272] In this embodiment, openings are formed at both opposite ends of the shell 11 along the first direction X. When assembling the battery cell 10 , the electrode assembly 2 can enter the shell 11 from any end of the shell 11 , which can effectively improve the assembly efficiency of the battery cell 10 .

[0273] In some embodiments, please refer to Fig.23 , Fig.23 for Fig.21 The schematic diagram of the structure of the housing 11 is shown. The housing 11 is an integrally formed structure.

[0274] As an example, the housing 1 may include a first wall portion 111, a second wall portion 112, a third wall portion 113, and a fourth wall portion 114. The first wall portion 111 and the second wall portion 112 are arranged opposite to each other along the thickness direction Z of the first wall portion, the third wall portion 113 and the fourth wall portion 114 are arranged opposite to 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 in sequence, and the thickness direction Z of the first wall portion, the first direction X, and the second direction Y are perpendicular to each other. The first wall portion 111, the second wall portion 112, the third wall portion 113, and the fourth wall portion 114 are integrally formed. The housing 1 may be formed from a sheet material by stamping or stretching.

[0275] In this embodiment, the shell 11 is an integrally formed structure, which can improve the strength of the shell 11 , improve the anti-destruction ability of the shell 11 , and improve the service life of the shell 11 .

[0276] In some embodiments, please refer to Figure 24-26 , Fig.24 A schematic diagram of the structure of the housing 11 provided in some other embodiments of the present application; Fig.25 for Fig.24 The cross-sectional view of the housing 11 shown is taken along the YZ plane; Fig.26 for Fig.25 The shell 11 is shown in an expanded view. The shell 11 is formed by bending a plate, and along the circumference of the opening of the shell 11, the first and second ends of the plate are connected to each other.

[0277] Taking the case where the housing 11 includes the first wall portion 111 , the third wall portion 113 , the second wall portion 112 and the fourth wall portion 114 as an example, the first wall portion 111 , the third wall portion 113 , the second wall portion 112 and the fourth wall portion 114 are sequentially arranged along the circumferential direction of the opening.

[0278] Along the circumference of the opening, the first and second ends of the plate are respectively a first end 1121 and a second end 1122. Fig.26 As shown, before the shell 11 is formed, the plate has two opposite end faces, the two end faces are the first end face 1121a and the second end face 1122a, the portion of the plate offset from the first end face 1121a in the direction close to the second end face 1122a within the region of the first preset distance L6 is the first end 1121 of the plate, and the length of the first end 1121 is equal to the first preset distance L6; the portion of the plate offset from the second end face 1122a in the direction close to the first end face 1121a within the region of the second preset distance L7 is the second end 1122 of the plate, and the length of the second end 1122 is equal to the second preset distance L7. The first preset distance L6 and the second preset distance L7 may be equal or different.

[0279] The two ends of the plate (the first end 1121 and the second end 1122) can be connected in a variety of ways, such as welding, bonding, hot melt connection, etc. The connection position of the two ends can be located on a wall portion of the shell 11, for example, the connection position of the two ends is located on the first wall portion 111, the second wall portion 112, the third wall portion 113 or the fourth wall portion 114; the connection position of the two ends can also be located at the intersection of two adjacent walls of the shell 11, and the intersection is the corner area of ​​the shell 11.

[0280] When forming the shell 11 , it is only necessary to bend the plate and connect the two ends of the plate to each other. The forming method of the shell 11 is simple and can effectively reduce the difficulty of forming the shell 11 .

[0281] In some embodiments, two ends of the plate are connected by welding to form a second weld print 115 .

[0282] The second weld mark 115 is formed at the welding position of the two ends, and the second weld mark 115 can be the part where the two ends are melted together. If the first end face 1121a and the second end face 1122a are arranged opposite to 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 penetration welding.

[0283] In this embodiment, the two ends of the plate are welded and connected, so that the two ends have good connection strength and are more firmly connected.

[0284] In some embodiments, the housing 11 further includes a second wall portion 112 , and the first wall portion 111 and the second wall portion 112 are disposed opposite to each other along the thickness direction Z of the first wall portion. The second weld print portion 115 is located on the second wall portion 112 .

[0285] As an example, the first and second ends of the plate together form the second wall portion 112 , that is, a portion of the second wall portion 112 is the first end portion 1121 , and another portion of the second wall portion 112 is the second end portion 1122 .

[0286] In this embodiment, the second weld mark 115 is located on the second wall 112, so that the second weld mark 115 and the pressure relief mechanism 3 are located on two opposite walls of the shell 11, reducing the influence 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 the embodiment where the third wall 113 and the fourth wall 114 are the walls with the largest outer surface area in the shell 1, when the electrode assembly 2 expands, the first wall 111 and the second wall 112 are less affected by the electrode assembly 2 than the third wall 113 and the fourth wall 114, and the deformation of the first wall 111 and the second wall 112 is less than the deformation of the third wall 113 and the fourth wall 114. Since the second weld mark 115 is located on the second wall 112, the influence of the expansion of the electrode assembly 2 on the second weld mark 115 can be reduced, and the risk of the shell 11 being damaged from the position of the second weld mark 115 due to the expansion of the electrode assembly 2 is reduced.

[0287] In some embodiments, the housing 1 is in a rectangular parallelepiped shape, and the first direction X is parallel to the length direction of the housing 1 .

[0288] As an example, the length of the housing 1 is greater than or equal to the height and width of the housing 1 .

[0289] In this embodiment, the housing 1 is in the shape of a rectangular parallelepiped, and the housing 1 is simple in structure and easy to form. When the battery cell 10 is applied to the battery 100, the housing 1 of the battery cell 10 is in the shape of a rectangular parallelepiped, which can reduce the installation gap between the battery cells 10 and is conducive to improving the volume energy density of the battery 100.

[0290] The embodiment of the present application provides a battery 100 , which is the battery cell 10 provided by any one of the above embodiments.

[0291] An embodiment of the present application provides an electrical device, and a battery cell 10 provided by any one of the above embodiments, wherein the battery cell 10 is used to provide electrical energy to the electrical device.

[0292] The embodiment of the present application also provides a battery cell 10, including a shell 1 and an electrode assembly 2, wherein the electrode assembly 2 is accommodated in the shell 1. The shell 1 is a rectangular parallelepiped, and includes a shell 11 and two end caps 12. Along the first direction X, both opposite ends of the shell 11 are formed with openings, and each end cap 12 closes an 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. 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 in sequence. The first wall portion 111 and the second wall portion 112 are arranged oppositely along the thickness direction Z of the first wall portion, and the third wall portion 113 and the fourth wall portion 114 are arranged oppositely along the 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 a tab 22. The tabs 22 are provided at opposite ends of the main body 21 along the first direction X. The two end caps 12 are provided with electrode terminals 4. The tab 22 at one end of the main body 21 is electrically connected to the electrode terminal 4 on one end cap 12, and the tab 22 at the other end of the main body 21 is electrically connected to the electrode terminal 4 on the other end cap 12. The first wall 111 supports the main body 21 along the gravity direction, and a channel gap 13 is formed between the second wall 112 and the main body 21. The channel gap 13 is configured to connect the space inside the housing 1 at both ends of the main body 21 along the first direction X. The thickness of the first wall 111 is equal to the thickness of the second wall 112, and the thickness of the third wall 113 and the thickness of the fourth wall 114 are both less than the thickness of the first wall 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 a plurality of sub-areas 211. The plurality of sub-areas 211 are continuously arranged along the first direction X. The length of the main body portion 21 is L, and the length of the sub-area 211 is L1. L=L1×N, L≥400mm, and N=2. Along the thickness direction Z of the first wall portion, the projection of each pressure relief mechanism 3 is correspondingly located in a sub-area 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 away from the main body portion 21. The area of ​​the first outer surface 1113 is S2, and 0.05≤S1 / S2≤0.55.

[0293] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0294] The above embodiments are only used to illustrate the technical solution of the present application and are not used to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: The housing comprises a first wall portion, wherein the first wall portion is provided with N pressure relief mechanisms arranged along a first direction; An electrode assembly is contained in the housing, wherein the electrode assembly is a winding structure formed by winding a positive electrode sheet, a separator and a negative electrode sheet, or the electrode assembly is a laminated structure formed by stacking a positive electrode sheet, a separator and a negative electrode sheet; the electrode assembly comprises a main body and a tab, at least one end of the main body is provided with the tab, the main body comprises a plurality of sub-regions, and along the first direction, the plurality of sub-regions are continuously arranged, the length of the main body is L, and the length of the sub-region is L1, L=L1×N, L≥400mm, and N≥2; Wherein, along the thickness direction of the first wall portion, the projection of each of the pressure relief mechanisms is correspondingly located within one of the sub-regions, and the thickness direction of the first wall portion intersects with the first direction.

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

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

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

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

55.

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

35.

7. The battery cell according to claim 5, characterized in that: The predetermined pressure relief areas of the N pressure relief mechanisms are equal.

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

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

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

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

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

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

6.

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

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

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

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

18. The battery cell according to any one of claims 1 to 13, characterized in that: The pressure relief mechanism is integrally formed with the first wall portion.

19. The battery cell according to any one of claims 1 to 13, characterized in that: The pressure relief mechanism is separately provided with the first wall portion, the first wall portion is provided with a pressure relief hole, and the pressure relief mechanism is installed on the first wall portion and covers the pressure relief hole.

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

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

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

23. The battery cell according to claim 20, characterized in that: The pressure relief mechanism is welded to the bottom wall of the first groove to form a first weld mark.

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

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

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

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

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

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

30. The battery cell according to any one of claims 1 to 13, characterized in that: The housing comprises: A housing, at least one end of which is formed with an opening along the first direction, and the housing includes the first wall portion; The end covers correspond to the openings one by one, and the end covers close the openings.

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

32. The battery cell according to claim 30, characterized in that The shell is an integrally formed structure.

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

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

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

36. The battery cell according to any one of claims 1 to 13, characterized in that: The shell is in a rectangular parallelepiped shape, and the first direction is parallel to the length direction of the shell.

37. A battery, characterized in that: Comprising the battery cell according to any one of claims 1-36.

38. An electrical device, characterized in that: It comprises a battery cell as described in any one of claims 1 to 36, and the battery cell is used to provide electrical energy to the electrical device.

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