Battery cell, battery, and electric device

Abstract

Embodiments of the present application provide a battery cell, a battery, and an electric device. The battery cell comprises a casing, a first pressure relief mechanism, and a second pressure- relief mechanism. The casing is used for accommodating an electrode assembly. The first pressure relief mechanism and the second pressure relief mechanism are arranged on the casing at an interval, and the first pressure relief mechanism is started earlier than the second pressure relief mechanism. When the battery cell goes into thermal runaway, the first pressure relief mechanism is firstly started, such that a discharge medium positioned near the first pressure relief mechanism in the casing can be discharged through the first pressure relief mechanism; and as pressure in the casing is continuously increased and / or the started first pressure relief mechanism is blocked by the discharge medium, the second pressure relief mechanism is started, such that discharging of the discharge medium in the casing can be continued through the second pressure relief mechanism, thereby reducing the risk of aggravated thermal runaway reaction caused by heat and air pressure accumulation in the casing, and improving the reliability of the battery cell.

Description

Battery cells, batteries and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application (2023111199997) entitled “Battery Cell, Battery and Electrical Equipment” filed on September 1, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

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

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

[0006] Summary of the Invention

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

[0008] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell, a first pressure relief mechanism and a second pressure relief mechanism; the shell is used to accommodate an electrode assembly; the first pressure relief mechanism and the second pressure relief mechanism are arranged at intervals in the shell, and the first pressure relief mechanism is opened earlier than the second pressure relief mechanism.

[0009] In the above technical solution, the shell is provided with a first pressure relief mechanism and a second pressure relief mechanism, and the first pressure relief mechanism is opened earlier than the second pressure relief mechanism. When the battery cell thermally runs away, the first pressure relief mechanism can be opened first, and the emission medium inside the shell near the first pressure relief mechanism can be discharged through the first pressure relief mechanism. As the pressure inside the shell continues to increase and / or the opened first pressure relief mechanism is blocked by the emission medium, the second pressure relief mechanism can be opened, and the emission medium inside the shell can continue to be discharged through the second pressure relief mechanism, thereby reducing the risk of heat and air pressure accumulation inside the shell and aggravating the thermal runaway reaction, and improving the reliability of the battery cell.

[0010] In some embodiments, the opening pressure of the first pressure relief mechanism is P1, the opening pressure of the second pressure relief mechanism is P2, and P2-P1≥0.02 MPa. This allows a certain difference between the opening pressure of the second pressure relief mechanism and the opening pressure of the first pressure relief mechanism, which helps the first pressure relief mechanism open earlier than the second pressure relief mechanism.

[0011] In some embodiments, 0.05 MPa ≤ P2 - P1 ≤ 0.5 MPa. When P2 - P1 ≥ 0.05 MPa, the difference between the opening pressure of the second pressure relief mechanism and the opening pressure of the first pressure relief mechanism is further increased, delaying the opening of the second pressure relief mechanism. When P2 - P1 ≤ 0.5 MPa, the difference between the opening pressure of the second pressure relief mechanism and the opening pressure of the first pressure relief mechanism is not too large, reducing the risk of damage to the housing before the second pressure relief mechanism opens.

[0012] In some embodiments, the housing includes a first wall portion, which supports the electrode assembly along the direction of gravity, and at least one of the first and second pressure relief mechanisms is disposed on the first wall portion. Because the first wall portion is the portion of the housing that supports the electrode assembly and is compressed by the electrode assembly, the area within the housing near the first wall portion is more susceptible to blockage and air suffocation, hindering the discharge of the exhaust medium. However, disposing at least one of the first and second pressure relief mechanisms on the first wall portion further facilitates the discharge of the exhaust medium within the housing near the first wall portion, thereby improving the reliability of the battery cells.

[0013] In some embodiments, the first pressure relief mechanism is disposed on the first wall portion. The exhaust medium inside the housing near the first wall portion can be discharged through the first pressure relief mechanism that is activated first, thereby achieving timely pressure relief for the battery cells.

[0014] In some embodiments, the housing includes a shell and two end caps; the shell has openings formed at opposite ends; the two end caps respectively seal the openings at the ends of the shell; and the first wall is formed on the shell. The shell can provide more space for the pressure relief mechanism disposed on the first wall, thereby reducing the difficulty of molding the pressure relief mechanism.

[0015] In some embodiments, both the first and second pressure relief mechanisms are located on the first wall. This provides the housing with a stronger pressure relief capability, allowing the exhaust medium within the housing near the first wall to be discharged more quickly. In the event of thermal runaway of a battery cell, the exhaust medium within the housing can be discharged from the side of the housing, reducing the risk of damage to external components located outside the end cap.

[0016] In some embodiments, one of the first and second pressure relief mechanisms is disposed on the first wall, and the other is disposed on an end cap. Thus, the housing and the end cap both have pressure relief capabilities. When a battery cell experiences thermal runaway, causing both the first and second pressure relief mechanisms to activate, the exhaust medium within the battery cell can be discharged from the sides and ends of the housing.

[0017] In some embodiments, the two end caps are disposed opposite each other along a first direction, the electrode assembly includes a main body and a tab, and the tab is disposed at at least one end of the main body along the first direction; the housing includes a second wall portion, the second wall portion being disposed opposite the first wall portion, the first wall portion supporting the main body along the direction of gravity, a channel gap being formed between the second wall portion and the main body portion, and the channel gap being configured to connect spaces within the housing located at opposite ends of the main body along the first direction, where the first direction intersects the direction of gravity. Because the channel gap is formed between the second wall portion and the main body portion, and because the channel gap connects spaces within the housing located at opposite ends of the main body along the first direction, a discharge medium within the housing located at opposite ends of the main body portion can flow through the channel gap, thereby facilitating rapid discharge of the discharge medium within the housing. For example, the first pressure relief mechanism and the second pressure relief mechanism are both arranged on the first wall portion, or the first pressure relief mechanism is arranged on the end cover, and the second pressure relief mechanism is arranged on the first wall portion. When the first pressure relief mechanism is opened and the second pressure relief mechanism is not opened, the emission medium accumulated near the end of the main body close to the first pressure relief mechanism can be discharged through the first pressure relief mechanism, and the emission medium accumulated near the end of the main body away from the first pressure relief mechanism can flow through the channel gap to the end of the main body close to the first pressure relief mechanism, and finally be discharged through the first pressure relief mechanism, so that the emission medium inside the battery cell can be discharged quickly, thereby improving the timeliness of the pressure relief of the battery cell.

[0018] In some embodiments, the housing includes a shell and an end cap; an opening is formed at one end of the shell; the end cap seals the opening; the end cap is a first wall; or the wall of the shell opposite the end cap is the first wall. If the end cap is the first wall, it is located at the bottom of the shell and supports the electrode assembly. In the event of thermal runaway of the battery cell, the exhaust medium inside the shell can be discharged through the end cap located at the bottom of the shell. If the wall of the shell opposite the end cap is the first wall, it is located at the bottom of the shell and supports the electrode assembly. In the event of thermal runaway of the battery cell, the exhaust medium inside the shell can be discharged through the wall located at the bottom of the shell.

[0019] In some embodiments, one of the first and second pressure relief mechanisms is disposed on the end cap, and the other is disposed on the wall of the housing opposite the end cap. In the event of thermal runaway of a battery cell, the discharge medium accumulated within the housing at both ends of the electrode assembly can be rapidly discharged from the opposite ends of the housing, thereby enhancing the pressure relief capability of the battery cell.

[0020] In some embodiments, the housing includes a shell and an end cap. Along a first direction, at least one end of the housing is formed with an opening, and the end cap corresponds to the opening one-to-one, sealing the opening. The housing has a first half and a second half. Along the first direction, the portion from the mid-section of the housing to one end of the housing is the first half, and the portion from the mid-section of the housing to the other end of the housing is the second half, with the mid-section being perpendicular to the first direction. A first pressure relief mechanism is provided in the first half, and a second pressure relief mechanism is provided in the second half. Thus, both the first and second half of the housing are provided with pressure relief mechanisms. Upon activation of the first pressure relief mechanism, the exhaust medium of the first half can be discharged through the first pressure relief mechanism. Upon activation of the second pressure relief mechanism, the exhaust medium of the second half can be discharged through the second pressure relief mechanism, thereby improving the timeliness of pressure relief of the battery cells.

[0021] In some embodiments, the length of the housing along the first direction is L, where L ≥ 80 mm. This facilitates achieving the high-capacity requirements of the battery cells. Furthermore, when L ≥ 80 mm, providing a first pressure relief mechanism and a second pressure relief mechanism in the first and second half regions, respectively, can alleviate the problem of delayed pressure relief in the battery cells.

[0022] In some embodiments, the housing has openings formed at opposite ends along a first direction. Two end caps seal the openings at both ends of the housing, and the end caps are located in the first and second halves, respectively. A first pressure relief mechanism and a second pressure relief mechanism are disposed on each end cap; or both the first and second pressure relief mechanisms are disposed on the housing; or the first pressure relief mechanism is disposed on the end cap located in the first half, and the second pressure relief mechanism is disposed on the portion of the housing located in the second half; or the first pressure relief mechanism is disposed on the portion of the housing located in the first half, and the second pressure relief mechanism is disposed on the end cap located in the second half. If the first and second pressure relief mechanisms are disposed on the end caps, exhaust medium accumulated at both ends of the electrode assembly within the housing can be quickly discharged from the opposite ends of the housing. If both the first and second pressure relief mechanisms are disposed on the housing, exhaust medium within the housing can be discharged from the sides of the housing, reducing the risk of damage to external components located outside the end caps. If one of the first and second pressure relief mechanisms is disposed on the end cap and the other on the housing, exhaust medium within the housing can be discharged from the sides and ends of the housing.

[0023] In some embodiments, the battery cell further includes a first electrode terminal and a second electrode terminal of opposite polarity, both of which are electrically connected to the electrode assembly, and are disposed on two end caps. The two end caps are provided with the first electrode terminal and the second electrode terminal, respectively, to reduce the risk of interference between the first and second electrode terminals during assembly and the risk of short circuit between the first and second electrode terminals.

[0024] In some embodiments, an opening is formed at one end of the housing along a first direction, and one of the first and second pressure relief mechanisms is disposed on the end cap, while the other is disposed on the housing. This allows the housing and the end cap to have pressure relief capabilities, allowing emissions from the battery cells to be discharged in different directions in the event of thermal runaway.

[0025] In some embodiments, the housing includes a first wall portion disposed opposite the end cap along a first direction, with one of the end cap and the first wall portion located in the first half and the other in the second half. One of the first and second pressure relief mechanisms is disposed on the end cap, while the other is disposed on the first wall portion. In the event of thermal runaway of a battery cell, the discharge medium accumulated within the housing at both ends of the electrode assembly can be rapidly discharged from the opposite ends of the housing, thereby enhancing the pressure relief capability of the battery cell.

[0026] In some embodiments, the battery cell further includes a first electrode terminal and a second electrode terminal of opposite polarity, both of which are electrically connected to the electrode assembly and are disposed on the end cap. This reduces the difficulty of assembling the first and second electrode terminals and facilitates electrical connection of the first and second electrode terminals to external components. Furthermore, the first and second electrode terminals can share space on the end cap with the pressure relief mechanism on the end cap, eliminating the need for the pressure relief mechanism to occupy additional space outside the end cap.

[0027] In some embodiments, the housing includes a first wall portion, with a first pressure relief mechanism and a second pressure relief mechanism both disposed on the first wall portion. The first pressure relief mechanism is provided with a first scored groove, and the second pressure relief mechanism is provided with a second scored groove. The first scored groove and the second scored groove are spaced apart along a first direction. Along the first direction, the housing has a length L, a maximum span of the first scored groove is L1, and a maximum span of the second scored groove is L2. 0.2 ≤ (L1 + L2) / L ≤ 0.6. (L1 + L2) / L ≥ 0.2, which facilitates increasing the total pressure relief area of ​​the first and second pressure relief mechanisms on the first wall portion, thereby improving the pressure relief rate of the battery cells. (L1 + L2) / L ≤ 0.6, which ensures that the sum of the maximum spans of the first and second scored grooves along the first direction is not excessive, thereby reducing the dimensions of the first and second pressure relief mechanisms along the first direction and improving the strength of the first wall portion.

[0028] In some embodiments, the housing includes a first wall portion, and the first and second pressure relief mechanisms are both disposed on the first wall portion. The first wall portion has a first outer surface facing away from the electrode assembly. The area of ​​the first outer surface is S. The predetermined pressure relief area of ​​the first pressure relief mechanism is S1, and the predetermined pressure relief area of ​​the second pressure relief mechanism is S2, satisfying the following conditions: 0.05 ≤ (S1 + S2) / S ≤ 0.55. (S1 + S2) / S ≥ 0.05, resulting in a larger total pressure relief area for the first and second pressure relief mechanisms, which is beneficial for increasing the pressure relief rate and timeliness of the pressure relief of the battery cells. (S1 + S2) / S ≤ 0.55, which is beneficial for increasing the strength of the first wall portion.

[0029] In some embodiments, 0.15≤(S1+S2) / S≤0.35.

[0030] In some embodiments, the first pressure relief mechanism includes a first weakened area and a first pressure relief area. The first pressure relief area is configured to open when the first weakened area ruptures. The area of ​​the first pressure relief area is S1. When the first pressure relief mechanism is opened, the first pressure relief area can open with the first weakened area as the boundary, thereby increasing the pressure relief area of ​​the first pressure relief mechanism.

[0031] In some embodiments, the first pressure relief mechanism is provided with a first notch groove, and the first pressure relief mechanism forms a first weakened area in the region where the first notch groove is provided. Providing the first notch groove on the first pressure relief mechanism simplifies the formation of the first weakened area, thereby reducing the difficulty of forming the first weakened area.

[0032] In some embodiments, the first scored groove is a groove extending along a closed trajectory and is disposed around the first pressure relief area. During activation of the first pressure relief mechanism, the first pressure relief area can be separated from the housing, thereby increasing the pressure relief area of ​​the first pressure relief mechanism and improving the pressure relief rate of the battery cell.

[0033] In some embodiments, the second pressure relief mechanism includes a second weakened area and a second pressure relief area. The second pressure relief area is configured to open when the second weakened area ruptures. The area of ​​the second pressure relief area is S2. When the second pressure relief mechanism is opened, the second pressure relief area can open with the second weakened area as the boundary, thereby increasing the pressure relief area of ​​the second pressure relief mechanism.

[0034] In some embodiments, the second pressure relief mechanism is provided with a second scored groove, and the second pressure relief mechanism forms a second weak zone in the area where the second scored groove is provided. By providing the second scored groove on the second pressure relief mechanism to form the second weak zone, the second weak zone is formed in a simple manner, thereby reducing the difficulty of forming the second weak zone.

[0035] In some embodiments, the second scored groove is a groove extending along a closed trajectory and is disposed around the second pressure relief area. When the second pressure relief mechanism is activated, the second pressure relief area can be separated from the housing, thereby increasing the pressure relief area of ​​the second pressure relief mechanism and improving the pressure relief rate of the battery cell.

[0036] In some embodiments, the predetermined pressure relief area of ​​the first pressure relief mechanism is S1, and the predetermined pressure relief area of ​​the second pressure relief mechanism is S2, satisfying: S1-S2≥50mm 2 This allows the first pressure relief mechanism to open its valve earlier than the second pressure relief mechanism. In the event of thermal runaway of a battery cell, pressure can be released first through the first pressure relief mechanism, which has a larger pressure relief area. This reduces the risk of a rapid increase in pressure or temperature inside the housing and improves the reliability of the battery cell.

[0037] In some embodiments, S1-S2≥100 mm 2 .

[0038] 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.

[0039] 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

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0041] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0042] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0043] FIG3 is an exploded view of a battery cell provided in some embodiments of the present application;

[0044] FIG4 is a cross-sectional view of the battery cell shown in FIG3 ;

[0045] FIG5 is a view of the battery cell shown in FIG4 taken along the direction of arrow A;

[0046] FIG6 is an exploded view of a battery cell provided in some other embodiments of the present application;

[0047] FIG7 is a cross-sectional view of the battery cell shown in FIG6;

[0048] FIG8 is a schematic structural diagram of the housing shown in FIG7 ;

[0049] FIG9 is an isometric view of a battery cell (one end of the housing is opened) provided in some embodiments of the present application;

[0050] FIG10 is an exploded view of the battery cell shown in FIG9 ;

[0051] FIG11 is a schematic structural diagram of the housing shown in FIG10 ;

[0052] FIG12 is an isometric view of a battery cell (one end of the housing is opened) provided in some other embodiments of the present application;

[0053] FIG13 is an isometric view of a battery cell (with openings formed at opposite ends of the housing) provided in some embodiments of the present application;

[0054] FIG14 is an isometric view of a battery cell (with openings formed at opposite ends of the housing) provided in some other embodiments of the present application;

[0055] FIG15 is an isometric view of a battery cell (with openings formed at opposite ends of the housing) provided in some further embodiments of the present application;

[0056] FIG16 is an isometric view of a battery cell (with openings formed at opposite ends of the housing) provided in yet other embodiments of the present application;

[0057] FIG17 is a schematic structural diagram of a housing provided in some embodiments of the present application;

[0058] FIG18 is a BB cross-sectional view of the housing shown in FIG17 ;

[0059] FIG19 is a partial enlarged view of a portion C of the housing shown in FIG18 ;

[0060] FIG20 is a partial view of a first wall portion provided in some embodiments of the present application;

[0061] FIG21 is a partial view of a first wall portion provided in some other embodiments of the present application;

[0062] FIG22 is a partial view of the first wall portion provided in some further embodiments of the present application.

[0063] Icons: 1-housing; 1a-first half; 1b-second half; 11-housing; 12-end cover; 13-first wall; 131-first outer surface; 14-second wall; 15-third wall; 151-second outer surface; 16-fourth wall; 161-third outer surface; 17-channel gap; 171-first space; 172-second space; 18-fifth wall; 2-electrode assembly; 21-main body; 22-electrode ear; 3-pressure relief mechanism; 31-first pressure relief mechanism; 311-first notch; 3111-first arc segment; 3112-first straight segment; 3113-second straight segment; 31 14-third straight line segment; 3115-fourth straight line segment; 3116-fifth straight line segment; 3117-first connecting line; 3118-second connecting line; 312-first weak area; 313-first pressure relief area; 32-second pressure relief mechanism; 321-second notch groove; 4-electrode terminal; 41-first electrode terminal; 42-second electrode terminal; 5-current collecting 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-third direction. DETAILED DESCRIPTION

[0064] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0065] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0066] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0067] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0068] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0069] The term "plurality" used in this application refers to two or more (including two).

[0070] 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.

[0071] Battery cells include but are not limited to lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0072] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process, active ions (such as lithium ions) move back and forth between the positive and negative electrodes. A separator, placed between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0073] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0074] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0075] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0076] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0077] In some embodiments, a positive electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, among others. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0078] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0079] As an example, the negative electrode current collector can be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium can be used. The metal foam can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0080] 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.

[0081] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0082] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0083] 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.

[0084] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical and mechanical stability.

[0085] As an example, the separator can be made of at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. In the case of a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0086] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0087] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0088] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0089] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0090] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0091] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0092] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0093] 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.

[0094] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0095] 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.

[0096] In some embodiments, the electrode assembly is a laminate structure.

[0097] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0098] 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.

[0099] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0100] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0101] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0102] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0103] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0104] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0105] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. Prismatic battery cells include square-shell battery cells, blade-shaped battery cells, and polygonal prismatic batteries. Polygonal prismatic batteries are, for example, hexagonal prismatic batteries.

[0106] 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.

[0107] 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.

[0108] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0109] 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.

[0110] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0111] The development of battery technology must take into account multiple design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the reliability of battery cells must also be considered.

[0112] In battery technology, pressure relief mechanisms can be installed in battery cells to improve their reliability. These mechanisms have a significant impact on battery reliability. For example, short circuits and overcharging can cause thermal runaway within the battery cell, leading to a sudden increase in pressure or temperature. In these situations, the pressure relief mechanism releases internal pressure and temperature, reducing the likelihood of explosion or fire.

[0113] In a typical battery cell, the cell comprises a housing and an electrode assembly. The electrode assembly is housed within the housing and comprises a main body and tabs, with tabs provided at one or both ends of the main body along a predetermined direction. The housing is provided with only one pressure relief mechanism, located at one end of the housing along the predetermined direction. In the event of thermal runaway of the battery cell, this pressure relief mechanism discharges the exhaust medium within the housing to relieve pressure within the battery cell. In such a battery cell, the housing is provided with only one pressure relief mechanism, resulting in insufficient pressure relief capacity, untimely pressure relief, and poor reliability of the battery cell.

[0114] In view of this, an embodiment of the present application provides a battery cell, wherein a first pressure relief mechanism and a second pressure relief mechanism are provided on the outer shell, the first pressure relief mechanism and the second pressure relief mechanism are arranged at an interval, and the first pressure relief mechanism is opened earlier than the second pressure relief mechanism. In this way, the pressure relief capacity of the outer shell is enhanced. When the battery cell thermally runs away, the first pressure relief mechanism can be opened first, and the exhaust medium located near the first pressure relief mechanism inside the outer shell can be discharged through the first pressure relief mechanism. As the pressure inside the outer shell continues to increase and / or the opened first pressure relief mechanism is blocked by the exhaust medium, the second pressure relief mechanism can be opened, and the exhaust medium inside the outer shell can continue to be discharged through the second pressure relief mechanism, thereby reducing the risk of heat and air pressure accumulation inside the outer shell exacerbating the thermal runaway reaction and improving the reliability of the battery cell.

[0115] The battery cells described in the embodiments of the present application are suitable for batteries and electrical equipment using the battery cells.

[0116] Electrical equipment can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and electric tools, etc. Vehicles can be fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical equipment.

[0117] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0118] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of the present application. A battery 100 is disposed within vehicle 1000. Battery 100 can be located at the bottom, front, or rear of vehicle 1000. Battery 100 can be used to power vehicle 1000, for example, as an operating power source for vehicle 1000.

[0119] The vehicle 1000 may further include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0120] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0121] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a battery cell 10 and a housing 20, wherein the battery cell 10 is accommodated in the housing 20.

[0122] The housing 20 is a component that houses the battery cells 10 and provides a storage space for the battery cells 10. The housing 20 can have various structures. In some embodiments, the housing 20 can include a first portion 201 and a second portion 202, which overlap to define a storage space for the battery cells 10. The first portion 201 and the second portion 202 can have various shapes, such as a rectangular parallelepiped or a cylindrical shape. The first portion 201 can be a hollow structure with one side open, and the second portion 202 can be a hollow structure with one side open. The open side of the second portion 202 overlaps the open side of the first portion 201, thereby forming the housing 20 with a storage space. Alternatively, the first portion 201 can be a hollow structure with one side open, and the second portion 202 can be a plate-like structure. The second portion 202 overlaps the open side of the first portion 201, thereby forming the housing 20 with a storage space. The first portion 201 and the second portion 202 can be sealed by a sealing element, which can be a sealing ring, sealant, etc.

[0123] In the battery 100, there can be one or more battery cells 10. If there are multiple battery cells 10, the multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 10. Multiple battery cells 10 can be connected in series, parallel, or in a hybrid connection to form a battery module, which can then be connected in series, parallel, or in a hybrid connection to form a single unit and housed within the housing 20. Alternatively, all battery cells 10 can be directly connected in series, parallel, or in a hybrid connection, and then the entire unit formed by all battery cells 10 can be housed within the housing 20.

[0124] In some embodiments, the battery 100 may further include a busbar component, through which the multiple battery cells 10 can be electrically connected to each other, thereby enabling series connection, parallel connection, or hybrid connection of the multiple battery cells 10. The busbar component may be a metal conductor, such as copper, iron, aluminum, stainless steel, or aluminum alloy.

[0125] Please refer to Figure 3, which is an exploded view of a battery cell 10 provided in some embodiments of the present application. The battery cell 10 may include a housing 1, an electrode assembly 2, and a pressure relief mechanism 3.

[0126] 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 .

[0127] The housing 11 may be a hollow structure with an opening at one end, or may be a hollow structure with openings at opposite ends. The housing 11 may have various shapes, such as a cylindrical or prismatic shape. The housing 11 may be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc.

[0128] The end cap 12 is a component that closes the opening of the shell 11 to isolate the internal environment of the battery cell 10 from the external environment. The end cap 12 and the shell 11 together define a storage space for accommodating the electrode assembly 2, electrolyte and other components. The end cap 12 and the shell 11 can be connected by rolling, welding, etc. 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.

[0129] In an embodiment where the housing 11 is open at one end, one end cap 12 may be provided. In an embodiment where the housing 11 is open at two opposite ends, two end caps 12 may be provided, each of which closes the two openings of the housing 11, and the two end caps 12 and the housing 11 together define a receiving space.

[0130] 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 pressure relief mechanism 3 can be used to discharge the discharge medium inside the battery cell 10 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, gases generated by the reaction, flames, etc. The pressure relief mechanism 3 can be provided in the housing 11 or in the end cover 12. At least two pressure relief mechanisms 3 can be provided in the battery cell 10. It is understood that in the battery cell 10, there can be two, three, four, five or more pressure relief mechanisms 3.

[0131] In some embodiments, the battery cell 10 may further include an electrode terminal 4, which is disposed on the outer casing 1 and is used to electrically connect to the tab 22 of the electrode assembly 2 to input or output electrical energy from the battery cell 10. The electrode terminal 4 may be disposed on the shell 11 of the outer casing 1 or on the end cap 12 of the outer casing 1. The electrode terminal 4 and the tab 22 may be directly connected, for example, by direct welding. The electrode terminal 4 and the tab 22 may also be indirectly connected, for example, by indirect connection via the current collecting member 5.

[0132] As an example, as shown in Figure 3, the shell 11 is a hollow structure with openings formed at opposite ends. End covers 12 are provided at the opposite ends of the shell 11. Electrode terminals 4 are provided on the end covers 12 at both ends of the shell 11. Pole ears 22 are formed at the opposite ends of the electrode assembly 2. The pole ear 22 at one end of the electrode assembly 2 is a positive pole ear, and the pole ear 22 at the other end of the electrode assembly 2 is a negative pole ear. The electrode terminal 4 on one end cover 12 is electrically connected to the positive pole ear, and the electrode terminal 4 on the other end cover 12 is electrically connected to the negative pole ear.

[0133] Please refer to Figure 4, which is a cross-sectional view of the battery cell 10 shown in Figure 3. This embodiment of the present application provides a battery cell 10 comprising a housing 1, a first pressure relief mechanism 31, and a second pressure relief mechanism 32. The housing 1 is configured to accommodate the electrode assembly 2. The first pressure relief mechanism 31 and the second pressure relief mechanism 32 are spaced apart from each other in the housing 1, with the first pressure relief mechanism 31 opening earlier than the second pressure relief mechanism 32.

[0134] The housing 1 can be cylindrical, prismatic, or other shapes. The prismatic device can be a triangular prism, a quadrangular prism, a pentagonal prism, a hexagonal prism, or other shapes. The quadrangular prism can include a rectangular parallelepiped. The first and second pressure relief mechanisms 31, 32 are two pressure relief mechanisms 3 within the battery cell 10. In the event of thermal runaway of the battery cell 10, the first pressure relief mechanism 31 opens before the second pressure relief mechanism 32. The first pressure relief mechanism 31 can be closer to the thermal runaway region of the electrode assembly 2 than the second pressure relief mechanism 32. The second pressure relief mechanism 32 can open after a preset time has passed since the first pressure relief mechanism 31 opened. For example, after the first pressure relief mechanism 31 opens, the pressure within the housing 1 continues to increase, and the pressure near the second pressure relief mechanism 32 reaches the opening pressure of the second pressure relief mechanism 32, at which point the second pressure relief mechanism 32 opens. As an example, the preset time is 1 to 8 minutes, for example, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, etc. It is also possible that after the first pressure relief mechanism 31 is opened, the second pressure relief mechanism 32 is not opened. For example, after the first pressure relief mechanism 31 is opened, as the emissions inside the shell 1 are discharged, the thermal runaway reaction of the electrode assembly 2 does not continue to spread, and the pressure near the second pressure relief mechanism 32 never reaches the opening pressure of the second pressure relief mechanism 32, and the second pressure relief mechanism 32 is not opened.

[0135] The first pressure relief mechanism 31 and the wall portion corresponding to the housing 1 can be integrally formed, or they can be provided separately from the wall portion corresponding to the housing 1, with the first pressure relief mechanism 31 mounted on this wall portion. The second pressure relief mechanism 32 and the wall portion corresponding to the housing 1 can be integrally formed, or they can be provided separately from the wall portion corresponding to the housing 1, with the second pressure relief mechanism 32 mounted on this wall portion.

[0136] The first pressure relief mechanism 31 and the second pressure relief mechanism 32 are spaced apart from each other in the housing 1 , that is, the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are independently disposed, with a distance between them and no contact or direct connection. Both the first pressure relief mechanism 31 and the second pressure relief mechanism 32 can be used to relieve pressure within the battery cell 10 . The opening pressure of the first pressure relief mechanism 31 and the opening pressure of the second pressure relief mechanism 32 can be different. For example, the opening pressure of the first pressure relief mechanism 31 can be lower than the opening pressure of the second pressure relief mechanism 32, so that the first pressure relief mechanism 31 opens before the second pressure relief mechanism 32 . The opening pressure of the first pressure relief mechanism 31 and the opening pressure of the second pressure relief mechanism 32 can also be equal. In this case, when the battery cell 10 thermally runs away, the pressure inside the housing 1 near the first pressure relief mechanism 31 can be higher than the pressure near the second pressure relief mechanism 32, so that the first pressure relief mechanism 31 opens before the second pressure relief mechanism 32. The opening pressure of the first pressure relief mechanism 31 can also be referred to as the detonation pressure of the first pressure relief mechanism 31. The pressure inside the housing 1 near the first pressure relief mechanism 31 at the moment the first pressure relief mechanism 31 is just opened is the opening pressure of the first pressure relief mechanism 31. The opening pressure of the second pressure relief mechanism 32 can also be referred to as the detonation pressure of the second pressure relief mechanism 32. It is the pressure inside the housing 1 near the second pressure relief mechanism 32 at the moment the second pressure relief mechanism 32 is just opened.

[0137] When determining the opening status of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 in the battery cell 10, the battery cell 10 can be fully charged with 1C at room temperature (25°C±2°C) and left to stand for 1 hour. Then, a needle penetration test can be performed in accordance with GB / T31485-2015 to put the battery cell 10 in a thermal runaway state. The opening sequence of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 can be recorded using a camera.

[0138] In this embodiment, the shell 1 is provided with a first pressure relief mechanism 31 and a second pressure relief mechanism 32, and the first pressure relief mechanism 31 is opened earlier than the second pressure relief mechanism 32. When the battery cell 10 thermally runs away, the first pressure relief mechanism 31 can be opened first, and the emission medium located near the first pressure relief mechanism 31 inside the shell 1 can be discharged through the first pressure relief mechanism 31. As the pressure inside the shell 1 continues to increase and / or the opened first pressure relief mechanism 31 is blocked by the emission medium, the second pressure relief mechanism 32 can be opened, and the emission medium inside the shell 1 can continue to be discharged through the second pressure relief mechanism 32, thereby reducing the risk of heat and air pressure accumulation inside the shell 1 and aggravating the thermal runaway reaction, thereby improving the reliability of the battery cell 10.

[0139] In addition, since the first pressure relief mechanism 31 opens earlier than the second pressure relief mechanism 32, after the first pressure relief mechanism 31 is opened and before the second pressure relief mechanism 32 is opened, the emissions inside the shell 1 located in the first pressure relief mechanism 31 can only be discharged through the first pressure relief mechanism 31, which can reduce the risk of emissions near the first pressure relief mechanism 31 spreading to other areas and causing aggravated thermal runaway.

[0140] In some embodiments, the opening pressure of the first pressure relief mechanism 31 is P1, the opening pressure of the second pressure relief mechanism 32 is P2, and P2-P1≥0.02 MPa.

[0141] In this embodiment, P2-P1 can be any point value among 0.02Mpa, 0.05Mpa, 0.08Mpa, 0.1Mpa, 0.2Mpa, 0.3Mpa, 0.4Mpa, 0.5Mpa, 0.6Mpa, 0.7Mpa, 0.8Mpa, 0.9Mpa, 1Mpa, etc., or a range value between any two of them.

[0142] A method for measuring the opening pressure of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 is as follows: a first air pipe is connected to the housing 1 near the first pressure relief mechanism 31, and the maximum distance between the connection position of the first air pipe and the housing 1 and the first pressure relief mechanism 31 is not greater than 15 mm; a second air pipe is connected to the housing 1 near the second pressure relief mechanism 32, and the maximum distance between the connection position of the second air pipe and the housing 1 and the second pressure relief mechanism 32 is not greater than 15 mm, and the first air pipe and the second air pipe are connected to a first air pressure sensor and a second air pressure sensor, respectively; the battery cell 10 can be fully charged with 1C at room temperature (25°C±2°C) and left to stand for 1 hour, and then a needle penetration test is performed in accordance with GB / T31485-2015 to put the battery cell 10 in a thermal runaway state, and the pressure of the first pressure relief mechanism 31 when it is just opened is obtained by the first air pressure sensor to obtain the opening pressure of the first pressure relief mechanism 31, and the pressure of the second pressure relief mechanism 32 when it is just opened is obtained by the second air pressure sensor to obtain the opening pressure of the second pressure relief mechanism 32.

[0143] In this embodiment, a certain difference exists between the opening pressure of the second pressure relief mechanism 32 and the opening pressure of the first pressure relief mechanism 31 , which is conducive to enabling the first pressure relief mechanism 31 to open earlier than the second pressure relief mechanism 32 .

[0144] In some embodiments, 0.05 MPa ≤ P2 - P1 ≤ 0.5 MPa.

[0145] In this embodiment, P2-P1 can be any point value among 0.05Mpa, 0.08Mpa, 0.12Mpa, 0.15Mpa, 0.18Mpa, 0.2Mpa, 0.22Mpa, 0.25Mpa, 0.28Mpa, 0.3Mpa, 0.32Mpa, 0.35Mpa, 0.38Mpa, 0.4Mpa, 0.42Mpa, 0.45Mpa, 0.48Mpa, 0.5Mpa, etc., or a range value between any two of them.

[0146] In this embodiment, P2-P1≥0.05 MPa further increases the difference between the opening pressure of the second pressure relief mechanism 32 and the opening pressure of the first pressure relief mechanism 31, delaying the opening of the second pressure relief mechanism 32 and fully utilizing the pressure relief of the first pressure relief mechanism 31. P2-P1≤0.5 MPa prevents a significant difference between the opening pressure of the second pressure relief mechanism 32 and the opening pressure of the first pressure relief mechanism 31, thereby reducing the risk of damage to the housing 1 before the second pressure relief mechanism 32 opens.

[0147] In some embodiments, referring to FIG. 4 , the housing 1 includes a first wall 13 , which supports the electrode assembly 2 along the direction of gravity. At least one of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 is disposed on the first wall 13 .

[0148] The first wall 13 is a wall portion of the housing 1 that supports the electrode assembly 2 in the direction of gravity. The first wall 13 can bear the gravity of the electrode assembly 2. In the housing 1, the end cap 12 can be the first wall 13, or a wall portion in the shell 11 can be the first wall 13.

[0149] In this embodiment, the first pressure relief mechanism 31 and the second pressure relief mechanism 32 may both be arranged on the first wall portion 13; the first pressure relief mechanism 31 may be arranged on the first wall portion 13, and the second pressure relief mechanism 32 may not be arranged on the first wall portion 13; or the second pressure relief mechanism 32 may be arranged on the first wall portion 13, and the first pressure relief mechanism 31 may not be arranged on the first wall portion 13.

[0150] In this embodiment, since the first wall portion 13 is the wall portion in the outer shell 1 that supports the electrode assembly 2, at least one of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 is arranged on the first wall portion 13, so that the exhaust inside the outer shell 1 can be discharged from the bottom of the outer shell 1.

[0151] Since the first wall portion 13 is pressed by the electrode assembly 2, the area inside the shell 1 near the first wall portion 13 is more prone to blockage and air suffocation, which is not conducive to the discharge of the emission medium. However, setting at least one of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 on the first wall portion 13 is more conducive to the discharge of the emission medium inside the shell 1 near the first wall portion 13, thereby improving the reliability of the battery cell 10.

[0152] In some embodiments, please continue to refer to FIG. 4 , the first pressure relief mechanism 31 is disposed on the first wall portion 13 .

[0153] In this embodiment, the second pressure relief mechanism 32 may be provided on the first wall portion 13 , or the first wall portion 13 may not be provided.

[0154] In this embodiment, the first pressure relief mechanism 31 is provided on the first wall 13 , and the discharge medium inside the housing 1 near the first wall 13 can be discharged through the first pressure relief mechanism 31 opened first, thereby achieving timely pressure relief of the battery cell 10 .

[0155] In some embodiments, please continue to refer to Figure 4. The housing 1 includes a shell 11 and two end covers 12. Openings are formed at opposite ends of the shell 11. The two end covers 12 respectively close the openings at both ends of the shell 11. The first wall portion 13 is formed on the shell 11.

[0156] It is understood that the housing 11 is a hollow structure with openings formed at opposite ends. If only one of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 is disposed on the first wall portion 13 , the other may be disposed on another wall portion of the housing 11 or on one end cover 12 .

[0157] The two end caps 12 of the housing 1 are arranged opposite to each other along the first direction X. In an embodiment in which the electrode assembly 2 is a wound structure, the extension direction of the winding centerline of the electrode assembly 2 may be parallel to the first direction X.

[0158] In this embodiment, the first wall portion 13 forms a shell 11 , and the shell 11 can provide more space for the pressure relief mechanism 3 disposed on the first wall portion 13 , thereby reducing the difficulty of forming the pressure relief mechanism 3 .

[0159] It should be noted that, in other embodiments, when there are two end covers 12 in the housing 1 , one end cover 12 may serve as the first wall portion 13 that supports the electrode assembly 2 .

[0160] In some embodiments, referring to FIG. 5 , FIG. 5 is a view of the battery cell 10 shown in FIG. 4 taken along the arrow A. The first pressure relief mechanism 31 and the second pressure relief mechanism 32 are both disposed on the first wall portion 13 .

[0161] The first pressure relief mechanism 31 and the first wall portion 13 may be integrally formed, or they may be provided as separate components and connected, for example, by welding. The second pressure relief mechanism 32 and the first wall portion 13 may be integrally formed, or they may be provided as separate components and connected, for example, by welding. If both the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are provided as separate components from the first wall portion 13, they may be installed on the same side of the first wall portion 13 along the thickness direction of the first wall portion 13, or they may be installed on different sides of the first wall portion 13.

[0162] As an example, along the first direction X, the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are arranged at intervals.

[0163] In this embodiment, both the first and second pressure relief mechanisms 31, 32 are located on the first wall 13, giving the housing 11 a stronger pressure relief capability and enabling faster discharge of the exhaust medium within the housing 1 near the first wall 13. In the event of thermal runaway of the battery cell 10, the exhaust medium within the housing 1 can be discharged from the side of the housing 11, reducing the risk of damage to external components located outside the end cap 12. These external components may include a busbar connected to the electrode terminal 4, a temperature sensing element, a voltage sensing element, and the like.

[0164] In some embodiments, referring to Figures 6 and 7 , Figure 6 is an exploded view of a battery cell 10 provided in other embodiments of the present application; and Figure 7 is a cross-sectional view of the battery cell 10 shown in Figure 6 . One of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 is disposed on the first wall portion 13 , and the other is disposed on one of the end caps 12 .

[0165] The first pressure relief mechanism 31 may be provided on the first wall portion 13 , and the second pressure relief mechanism 32 may be provided on one end cover 12 ; or the second pressure relief mechanism 32 may be provided on the first wall portion 13 , and the first pressure relief mechanism 31 may be provided on one end cover 12 .

[0166] As an example, in Figures 6 and 7, the first pressure relief mechanism 31 is provided on the first wall portion 13, and the second pressure relief mechanism 32 is provided on one end cap 12. Along the first direction X, the first pressure relief mechanism 31 can be centrally located on the first wall portion 13, or the midpoint of the first pressure relief mechanism 31 can be offset from the midpoint of the first wall portion 13.

[0167] In this embodiment, the shell 11 and one end cover 12 both have pressure relief capabilities. When the battery cell 10 thermally runs away and the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are both opened, the discharge medium inside the battery cell 10 can be discharged from the side and end of the shell 1.

[0168] In some embodiments, please refer to Figures 7 and 8. Figure 8 is a schematic structural diagram of the housing 11 shown in Figure 7. Two end caps 12 are arranged relative to each other along a first direction X. The electrode assembly 2 includes a main body 21 and a tab 22. The tab 22 is provided at at least one end of the main body 21 along the first direction X. The housing 11 includes a second wall 14, which is arranged opposite to the first wall 13. The first wall 13 supports the main body 21 along the direction of gravity. A channel gap 17 is formed between the second wall 14 and the main body 21. The channel gap 17 is configured to connect the spaces within the housing 1 located at both ends of the main body 21 along the first direction X, where the first direction X intersects the direction of gravity.

[0169] Along the first direction X, the main body 21 may be provided with a tab 22 at only one end, or at both ends.

[0170] As an example, in Figure 7, the main body 21 is provided with tabs 22 at both ends along the first direction X. The tab 22 at one end is the positive tab, and the tab 22 at the other end is the negative tab. Both end caps 12 are provided with electrode terminals 4. The electrode terminal 4 on one end cap 12 is electrically connected to the positive tab, and the electrode terminal 4 on the other end cap 12 is electrically connected to the negative tab. The first direction X can be perpendicular to the direction of gravity, or it can be arranged at an acute or obtuse angle.

[0171] The electrode assembly 2 may include a positive electrode sheet, a negative electrode sheet, and a separator. The electrode assembly 2 may be a wound structure formed by winding the positive electrode sheet, separator, and negative electrode sheet, or a laminated structure formed by stacking the positive electrode sheet, separator, and negative electrode sheet. The main body 21 may be the portion of the electrode assembly 2 corresponding to the area of ​​the electrode sheet coated with the active material layer. The positive electrode tab may be the portion of the positive electrode sheet not coated with the positive electrode active material layer, and the negative electrode tab may be the portion of the negative electrode sheet not coated with the negative electrode active material layer.

[0172] The first wall 13 and the second wall 14 are two opposing walls of the housing 1. The first wall 13 supports the main body 21 in the direction of gravity. The thicknesses of the first and second walls 13, 14 can be equal or unequal. The first wall 13 can directly contact the main body 21 to support it. Alternatively, an intermediate member can be provided between the first wall 13 and the main body 21 to support the main body 21. The intermediate member can be an insulating member provided between the first wall 13 and the main body 21.

[0173] A channel gap 17 is formed between the second wall portion 14 and the main body 21. The spaces within the housing 1 located at both ends of the main body 21 along the first direction X are a first space 171 and a second space 172, respectively. First space 171 is formed between one end of the main body 21 and one end cap 12, while second space 172 is formed between one end of the main body 21 and the other end cap 12. Channel gap 17 connects first space 171 and second space 172. In the event of thermal runaway of the battery cell 10, the discharged medium from one of the first and second spaces 171, 172 can flow to the other through the gap.

[0174] As an example, as shown in FIG8 , the housing 11 may further include a third wall portion 15 and a fourth wall portion 16 . The first wall portion 13 and the second wall portion 14 are arranged relative to each other along a second direction Y, which is parallel to the direction of gravity. The third wall portion 15 and the fourth wall portion 16 are arranged relative to each other along a third direction Z. The first wall portion 13 , the third wall portion 15 , the second wall portion 14 , and the fourth wall portion 16 are connected end to end in sequence, and the first direction X, the second direction Y, and the third direction Z are perpendicular to each other. The distance between the inner surface of the first wall portion 13 and the inner surface of the second wall portion 14 is greater than the distance between the inner surface of the third wall portion 15 and the inner surface of the fourth wall portion 16 . In some embodiments, the thickness of the third wall portion 15 and the thickness of the fourth wall portion 16 are both less than the thickness of the first wall portion 13 , and the thickness of the second wall portion 14 is equal to the thickness of the first wall portion 13 . In other embodiments, the thicknesses of the first wall portion 13 , the second wall portion 14 , the third wall portion 15 , and the fourth wall portion 16 are equal.

[0175] In this embodiment, since a channel gap 17 is formed between the second wall portion 14 and the main body portion 21, and the channel gap 17 connects the space inside the shell 1 located at both ends of the main body portion 21 along the first direction X, the discharge medium inside the shell 1 located at both ends of the main body portion 21 can flow to each other through the channel gap 17, which is conducive to the rapid discharge of the discharge medium inside the shell 1. For example, the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are both arranged on the first wall portion 13, or the first pressure relief mechanism 31 is arranged on the end cover 12, and the second pressure relief mechanism 32 is arranged on the first wall portion 13. When the first pressure relief mechanism 31 is opened and the second pressure relief mechanism 32 is not opened, the emission medium accumulated near the end of the main body 21 close to the first pressure relief mechanism 31 can be discharged through the first pressure relief mechanism 31, and the emission medium accumulated near the end of the main body 21 away from the first pressure relief mechanism 31 can flow to the end of the main body 21 close to the first pressure relief mechanism 31 through the channel gap 17, and finally be discharged through the first pressure relief mechanism 31, so that the emission medium inside the battery cell 10 can be discharged quickly, thereby improving the timeliness of the pressure relief of the battery cell 10.

[0176] In some embodiments, please refer to Figures 9-11. Figure 9 is an isometric view of a battery cell 10 (one end of the housing 11 forms an opening) provided in some embodiments of the present application; Figure 10 is an exploded view of the battery cell 10 shown in Figure 9; and Figure 11 is a schematic structural diagram of the housing 11 shown in Figure 10. The outer shell 1 includes a housing 11 and an end cap 12. The housing 11 forms an opening at one end, and the end cap 12 closes the opening. The end cap 12 is a first wall 13; or, the wall of the housing 11 opposite the end cap 12 is the first wall 13.

[0177] The housing 11 has an opening at one end along the first direction X. The housing 11 has a wall portion opposite to the end cap 12 along the first direction X. In an embodiment in which the electrode assembly 2 has a wound structure, the extension direction of the winding centerline of the electrode assembly 2 may be parallel to the first direction X.

[0178] In the embodiment where the end cap 12 is the first wall portion 13, the end cap 12 supports the electrode assembly 2 in the direction of gravity, and at least one of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 is disposed on the end cap 12. Taking the first pressure relief mechanism 31 disposed on the end cap 12 as an example, the second pressure relief mechanism 32 can be disposed on the end cap 12 or on the housing 11.

[0179] In the embodiment where the wall portion of the housing 11 opposing the end cap 12 is the first wall portion 13, the wall portion of the housing 11 opposing the end cap 12 supports the electrode assembly 2 in the direction of gravity, and at least one of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 is disposed on the wall portion of the housing 11 opposing the end cap 12. Taking the example of the first pressure relief mechanism 31 being disposed on the wall portion of the housing 11 opposing the end cap 12, the second pressure relief mechanism 32 may be disposed on the end cap 12, or on the wall portion of the housing 11 surrounding the opening.

[0180] As an example, the electrode assembly 2 includes a main body 21 and tabs 22. Two tabs 22 are provided at one end of the main body 21 along a first direction X. The two tabs 22 are a positive tab and a negative tab, respectively. Two electrode terminals 4 are provided on the end cap 12. One electrode terminal 4 is electrically connected to the positive tab via a current collecting member 5, and the other electrode terminal 4 is electrically connected to the negative tab via another current collecting member 5.

[0181] In the embodiment shown in Figures 9-11, along the first direction X, the wall portion of the housing 11 opposite the end cap 12 is the first wall portion 13. The housing 11 includes a second wall portion 14, one end of which is connected to the first wall portion 13 and the other end of which extends to the opening of the housing 11. The first pressure relief mechanism 31 is disposed on the first wall portion 13, and the second pressure relief mechanism 32 is disposed on the second wall portion 14. In other embodiments, the second pressure relief mechanism 32 may be disposed on the first wall portion 13, and the first pressure relief mechanism 31 may be disposed on the second wall portion 14.

[0182] As an example, the housing 11 may further include a third wall portion 15, a fourth wall portion 16, and a fifth wall portion 18. The second wall portion 14, the third wall portion 15, the fourth wall portion 16, and the fifth wall portion 18 are connected end to end in sequence. The second wall portion 14, the third wall portion 15, the fourth wall portion 16, and the fifth wall portion 18 are arranged around the first wall portion 13. The second wall portion 14 and the fourth wall portion 16 are arranged opposite each other along the second direction Y, and the third wall portion 15 and the fifth wall portion 18 are arranged opposite each other along the third direction Z. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other. The distance between the inner surface of the second wall portion 14 and the inner surface of the fourth wall portion 16 is greater than the distance between the inner surface of the third wall portion 15 and the inner surface of the fifth wall portion 18.

[0183] If the end cover 12 is the first wall portion 13, the end cover 12 is located at the bottom of the outer shell 1 and supports the electrode assembly 2. When the battery cell 10 thermally runs away, the discharge medium inside the outer shell 1 can be discharged through the end cover 12 located at the bottom of the outer shell 1; if the wall portion of the shell 11 opposite to the end cover 12 is the first wall portion 13, the wall portion is located at the bottom of the outer shell 1 and supports the electrode assembly 2. When the battery cell 10 thermally runs away, the discharge medium inside the outer shell 1 can be discharged through the bottom portion located at the bottom of the outer shell 1.

[0184] In some embodiments, please refer to Figure 12, which is an isometric view of a battery cell 10 (with an opening formed at one end of the housing 11) provided in other embodiments of the present application. One of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 is disposed on the end cap 12, and the other is disposed on the wall of the housing 11 opposite the end cap 12.

[0185] The first pressure relief mechanism 31 may be provided on the end cover 12 , and the second pressure relief mechanism 32 may be provided on the wall opposite to the shell 11 and the end cover 12 ; or the second pressure relief mechanism 32 may be provided on the end cover 12 , and the first pressure relief mechanism 31 may be provided on the wall opposite to the shell 11 and the end cover 12 .

[0186] As an example, in FIG. 12 , the wall portion of the housing 11 opposite to the end cover 12 is the first wall portion 13 , the first pressure relief mechanism 31 is provided on the first wall portion 13 , and the second pressure relief mechanism 32 is provided on the end cover 12 .

[0187] In this embodiment, when the battery cell 10 thermally runs away, the discharge medium accumulated at both ends of the electrode assembly 2 inside the housing 1 can be quickly discharged from the opposite ends of the housing 1, thereby enhancing the pressure relief capability of the battery cell 10.

[0188] In some embodiments, please refer to Figures 12-16. Figure 13 is an isometric view of a battery cell 10 (with openings formed at opposite ends of the housing 11) provided in some embodiments of the present application; Figure 14 is an isometric view of a battery cell 10 (with openings formed at opposite ends of the housing 11) provided in other embodiments of the present application; Figure 15 is an isometric view of a battery cell 10 (with openings formed at opposite ends of the housing 11) provided in still other embodiments of the present application; and Figure 16 is an isometric view of a battery cell 10 (with openings formed at opposite ends of the housing 11) provided in yet other embodiments of the present application. The housing 1 includes a housing 11 and an end cap 12. Along a first direction X, at least one end of the housing 11 is formed with an opening. The end cap 12 corresponds to the opening and seals the opening. The housing 1 has a first half 1a and a second half 1b. Along the first direction X, the portion from the mid-section W of the housing 1 to one end of the housing 1 constitutes the first half 1a, and the portion from the mid-section W of the housing 1 to the other end of the housing 1 constitutes the second half 1b. The mid-section W is perpendicular to the first direction X. The first pressure relief mechanism 31 is disposed in the first half area 1 a , and the second pressure relief mechanism 32 is disposed in the second half area 1 b .

[0189] In this embodiment, the housing 1 may be cylindrical, prismatic, or other shapes. The housing 11 may be a hollow structure with an opening at one end, or a hollow structure with openings at two opposing ends. Along the first direction X, the midsection W is located in the middle of the housing 1, and the distances from the midsection W to the two ends of the housing 1 are equal.

[0190] In this embodiment, the first half zone 1a and the second half zone 1b of the shell 11 are both provided with a pressure relief mechanism 3. After the first pressure relief mechanism 31 is opened, the emission medium of the first half zone 1a can be discharged through the first pressure relief mechanism 31. After the second pressure relief mechanism 32 is opened, the emission medium of the second half zone 1b can be discharged through the second pressure relief mechanism 32, thereby improving the timeliness of pressure relief of the battery cell 10.

[0191] In some embodiments, along the first direction X, the length of the housing 1 is L, where L is ≥ 80 mm.

[0192] Along the first direction X, the housing 1 has two opposing end surfaces. The maximum distance between the two end surfaces is the length of the housing 1, and the distances from the mid-section W to the two end surfaces are equal. If the two end surfaces of the housing 1 are planar, the length of the housing 1 is measured based on the two end surfaces; if one or both end surfaces of the housing 1 have a convex or concave portion, the length of the housing 1 is measured based on the planar area of ​​the end surface. In an embodiment in which the housing 11 is a hollow structure with an opening at one end, the surface of the end cap 12 facing the exterior of the housing 1 along the first direction X can be one end surface of the housing 1, and the surface of the wall of the housing 11 and the end cap 12 facing the exterior of the housing 1 along the first direction X can be the other end surface of the housing 1. In an embodiment in which the housing 11 is a hollow structure with openings at opposite ends, the surface of one end cap 12 facing the exterior of the housing 1 along the first direction X can be one end surface of the housing 1, and the surface of the other end cap 12 facing the exterior of the housing 1 along the first direction X can be the other end surface of the housing 1.

[0193] In this embodiment, L can be any one of the point values ​​of 80mm, 100mm, 140mm, 160mm, 180mm, 200mm, 240mm, 260mm, 280mm, 300mm, 340mm, 360mm, 380mm, 400mm, 440mm, 460mm, 480mm, 500mm, 540mm, 560mm, 580mm, and 600mm, or a range value between any two of them.

[0194] In this embodiment, L≥80mm is conducive to achieving the large capacity requirement of the battery cell 10. In addition, when L≥80mm, the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are respectively provided in the first half area 1a and the second half area 1b, which can alleviate the problem of untimely pressure relief of the battery cell 10.

[0195] In some embodiments, L ≥ 160 mm.

[0196] In this embodiment, L can be any one of 160mm, 170mm, 180mm, 190mm, 200mm, 210mm, 220mm, 230mm, 240mm, 250mm, 260mm, 270mm, 280mm, 290mm, 300mm, 310mm, 320mm, 330mm, 340mm, 350mm, 360mm, 370mm, 380mm, 390mm, 400mm, 410mm, 420mm, 430mm, 440mm, 450mm, 460mm, 470mm, 480mm, 490mm, 500mm, 510mm, 520mm, 530mm, 540mm, 550mm, 560mm, 570mm, 580mm, 590mm, or 600mm, or a range value between any two of them.

[0197] For a typical battery cell 10, when the length of the housing 1 is greater than or equal to 160 mm, the pressure relief capability of the battery cell 10 is poor, and it is easy to experience delayed pressure relief. However, in the embodiment of the present application, the first pressure relief mechanism 31 is disposed in the first half 1a of the housing 1, and the second pressure relief mechanism 32 is disposed in the second half 1b of the housing 1. Moreover, the first pressure relief mechanism 31 is activated before the second pressure relief mechanism 32. Even when the length of the housing 1 is greater than or equal to 160 mm, the battery cell 10 can achieve timely pressure relief.

[0198] In some embodiments, referring to Figures 13-16 , openings are formed at opposite ends of the housing 11 along a first direction X. Two end caps 12 respectively seal the openings at both ends of the housing 11, and the two end caps 12 are located in the first half 1a and the second half 1b, respectively. A first pressure relief mechanism 31 and a second pressure relief mechanism 32 are respectively disposed on the two end caps 12; or, both the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are disposed on the housing 11; or, the first pressure relief mechanism 31 is disposed on the end cap 12 located in the first half 1a, and the second pressure relief mechanism 32 is disposed on the portion of the housing 11 located in the second half 1b; or, the first pressure relief mechanism 31 is disposed on the portion of the housing 11 located in the first half 1a, and the second pressure relief mechanism 32 is disposed on the end cap 12 located in the second half 1b.

[0199] It can be understood that a portion of the shell 11 is located in the first half area 1 a , and another portion of the shell 11 is located in the second half area 1 b .

[0200] In the embodiment shown in FIG13 , the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are respectively located in the two end covers 12 , so that the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are respectively located in the first half zone 1 a and the second half zone 1 b .

[0201] In the embodiment shown in FIG14 , the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are both disposed on the housing 11. The first pressure relief mechanism 31 is disposed on the portion of the housing 11 located in the first half 1a, and the second pressure relief mechanism 32 is disposed on the portion of the housing 11 located in the second half 1b, so that the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are located in the first half 1a and the second half 1b, respectively. The first pressure relief mechanism 31 and the second pressure relief mechanism 32 can be disposed on two walls of the housing 11, or on the same wall of the housing 11. For example, the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are both disposed on the first wall 13 of the housing 11 that supports the electrode assembly 2.

[0202] In the embodiment shown in Figure 15, the first pressure relief mechanism 31 is arranged on the end cover 12 located in the first half area 1a, and the second pressure relief mechanism 32 is arranged on the part of the shell 11 located in the second half area 1b, so that the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are respectively located in the first half area 1a and the second half area 1b.

[0203] In the embodiment shown in FIG. 16 , the first pressure relief mechanism 31 is provided at the portion of the housing 11 located in the first half 1 a , and the second pressure relief mechanism 32 is provided at the end cover 12 located in the second half 1 b .

[0204] If the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are respectively provided on the two end caps 12, the exhaust medium accumulated at the ends of the electrode assembly 2 within the housing 1 can be quickly discharged from the opposite ends of the housing 1. If the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are both provided on the shell 11, the exhaust medium within the housing 1 can be discharged from the sides of the housing 1, reducing the risk of damage to external components located outside the end caps 12 caused by the exhaust. If one of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 is provided on the end cap 12 and the other is provided on the shell 11, the exhaust medium within the housing 1 can be discharged from the sides and ends of the housing 1.

[0205] In some embodiments, please continue to refer to Figures 13-16. The battery cell 10 also includes a first electrode terminal 41 and a second electrode terminal 42 with opposite polarities. The first electrode terminal 41 and the second electrode terminal 42 are both electrically connected to the electrode assembly 2 (not shown in Figures 13-16). The first electrode terminal 41 and the second electrode terminal 42 are respectively arranged on the two end covers 12.

[0206] As an example, along the first direction X, the main body 21 of the electrode assembly 2 is provided with pole ears 22 at both opposite ends. The pole ear 22 at one end of the main body 21 is a positive pole ear, and the other end is a negative pole ear. One of the positive pole ear and the negative pole ear is electrically connected to the first electrode terminal 41, and the other is electrically connected to the second electrode terminal 42.

[0207] The two end caps 12 are respectively provided with a first electrode terminal 41 and a second electrode terminal 42, which reduces the risk of interference between the first and second electrode terminals 41, 42 during assembly and reduces the risk of short circuiting between the first and second electrode terminals 41, 42. As shown in FIG13 , in an embodiment where the first and second pressure relief mechanisms 31, 32 are respectively provided on the two end caps 12, the first pressure relief mechanism 31 and the first electrode terminal 41 can share the space of one end cap 12, eliminating the need for the first pressure relief mechanism 31 to occupy additional space outside the end cap 12. The second pressure relief mechanism 32 and the second electrode terminal 42 can share the space of the other end cap 12, eliminating the need for the second pressure relief mechanism 32 to occupy additional space outside the end cap 12.

[0208] In some embodiments, referring to FIG. 12 , an opening is formed at one end of the housing 11 along the first direction X. One of the first pressure relief mechanism 31 and the second pressure relief mechanism 32 is disposed on the end cover 12 , and the other is disposed on the housing 11 .

[0209] The first pressure relief mechanism 31 may be provided on the end cover 12 , and the second pressure relief mechanism 32 may be provided on the housing 11 ; or the second pressure relief mechanism 32 may be provided on the end cover 12 , and the first pressure relief mechanism 31 may be provided on the housing 11 .

[0210] As an example, in FIG. 12 , the first pressure relief mechanism 31 is provided on the housing 11 , and the second pressure relief mechanism 32 is provided on the end cover 12 .

[0211] In this embodiment, the housing 11 and the end cover 12 have pressure relief capabilities. When the battery cell 10 experiences thermal runaway, the exhaust inside the battery cell 10 can be discharged from different directions.

[0212] Continuing with FIG. 12 , in some embodiments, housing 11 includes a first wall portion 13 disposed opposite end cap 12 along a first direction X. One of end cap 12 and first wall portion 13 is located in first half 1a, and the other is located in second half 1b. One of first pressure relief mechanism 31 and second pressure relief mechanism 32 is disposed on end cap 12, while the other is disposed on first wall portion 13.

[0213] The first pressure relief mechanism 31 may be provided on the end cover 12 , and the second pressure relief mechanism 32 may be provided on the first wall portion 13 ; or the second pressure relief mechanism 32 may be provided on the end cover 12 , and the first pressure relief mechanism 31 may be provided on the first wall portion 13 .

[0214] 12 , the first pressure relief mechanism 31 is provided on the first wall 13, and the second pressure relief mechanism 32 is provided on the end cover 12. The first wall 13 is located at the bottom of the housing 11 and supports the main body 21 along the gravity direction (not shown in FIG12 ).

[0215] In this embodiment, both the end cover 12 and the first wall portion 13 are provided with a pressure relief mechanism 3. When the battery cell 10 thermally runs away, the discharge medium accumulated at both ends of the electrode assembly 2 inside the shell 1 can be quickly discharged from the opposite ends of the shell 1, thereby enhancing the pressure relief capability of the battery cell 10.

[0216] In some embodiments, please continue to refer to Figure 12, the battery cell 10 also includes a first electrode terminal 41 and a second electrode terminal 42 with opposite polarities, the first electrode terminal 41 and the second electrode terminal 42 are both electrically connected to the electrode assembly 2, and the first electrode terminal 41 and the second electrode terminal 42 are both arranged on the end cover 12.

[0217] Along the first direction X, two tabs 22 (not shown in FIG12 ) are provided at one end of the main body 21 . The two tabs 22 are respectively a positive tab and a negative tab. One of the positive tab and the negative tab is electrically connected to the first electrode terminal 41 , and the other is electrically connected to the second electrode terminal 42 .

[0218] In this embodiment, the first and second electrode terminals 41, 42 are both disposed on the end cap 12, which simplifies assembly and facilitates electrical connection between the first and second electrode terminals 41, 42 and external components, such as a busbar assembly for electrically connecting multiple battery cells 10. Furthermore, the first and second electrode terminals 41, 42 can share space within the end cap 12 with the pressure relief mechanism 3 on the end cap 12, eliminating the need for the pressure relief mechanism 3 to occupy additional space outside the end cap 12.

[0219] In some embodiments, please refer to FIG17 , which is a schematic structural diagram of a housing 1 provided in some embodiments of the present application. Housing 1 includes a first wall portion 13 , with a first pressure relief mechanism 31 and a second pressure relief mechanism 32 both disposed on first wall portion 13 . First pressure relief mechanism 31 is provided with a first notched groove 311 , and second pressure relief mechanism 32 is provided with a second notched groove 321 . First notched groove 311 and second notched groove 321 are spaced apart along a first direction X. Along the first direction X, housing 1 has a length L, a maximum span of first notched groove 311 is L1, and a maximum span of second notched groove 321 is L2, where 0.2 ≤ (L1 + L2) / L ≤ 0.6.

[0220] It can be understood that the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are provided on the same wall portion of the housing.

[0221] Along the first direction X, the housing 1 has two opposing end surfaces, and the maximum distance between the two end surfaces is the length of the housing 1. In an embodiment in which the housing 11 is a hollow structure with an opening at one end, the surface of the end cap 12 facing the outside of the housing 1 along the first direction X can be one end surface of the housing 1, and the surface of the wall portion of the housing 11 and the end cap 12 facing the outside of the housing 1 along the first direction X can be the other end surface of the housing 1. In an embodiment in which the housing 11 is a hollow structure with openings at opposite ends, the surface of one end cap 12 facing the outside of the housing 1 along the first direction X can be one end surface of the housing 1, and the surface of the other end cap 12 facing the outside of the housing 1 along the first direction X can be the other end surface of the housing 1. As an example, in FIG. 17 , there are two end caps 12 in the housing 1, and the outer surfaces of the two end caps 12 are the two opposing end surfaces of the housing 1 along the first direction X.

[0222] The maximum span of the first score groove 311 along the first direction X is the distance between the two positions of the first score groove 311 that are farthest apart along the first direction X. The maximum span of the second score groove 321 along the first direction X is the distance between the two positions of the second score groove 321 that are farthest apart along the first direction X. It can be L1=L2, L1>L2, or L1<L2.

[0223] The first notched groove 311 and / or the second notched groove 321 can be a groove extending along a closed trajectory, which can be circular, rectangular, etc.; the first notched groove 311 and / or the second notched groove 321 can also be a groove along a non-closed trajectory, which can be straight, arc-shaped, U-shaped, H-shaped, V-shaped, L-shaped, Y-shaped, X-shaped, etc. The first notched groove 311 can be arranged on the inner side of the first pressure relief mechanism 31 (the side of the first pressure relief mechanism 31 facing the electrode assembly 2 along the thickness direction of the first wall portion 13), and the first notched groove 311 can also be arranged on the outer side of the first pressure relief mechanism 31 (the side of the first pressure relief mechanism 31 facing away from the electrode assembly 2 along the thickness direction of the first wall portion 13); the second notched groove 321 can be arranged on the inner side of the second pressure relief mechanism 32 (the side of the second pressure relief mechanism 32 facing the electrode assembly 2 along the thickness direction of the first wall portion 13), and the second notched groove 321 can also be arranged on the outer side of the second pressure relief mechanism 32 (the side of the second pressure relief mechanism 32 facing away from the electrode assembly 2 along the thickness direction of the first wall portion 13).

[0224] In this embodiment, (L1+L2) / L 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.

[0225] In this embodiment, (L1+L2) / L≥0.2, which helps increase the total pressure relief area of ​​the first and second pressure relief mechanisms 31 and 32 on the first wall portion 13 and improves the pressure relief rate of the battery cell 10. (L1+L2) / L≤0.6 prevents the sum of the maximum spans of the first and second score grooves 311 and 321 along the first direction X from being too large, thus reducing the dimensions of the first and second pressure relief mechanisms 31 and 32 along the first direction X and improving the strength of the first wall portion 13.

[0226] In some embodiments, please refer to Figures 17 and 18. Figure 18 is a BB cross-sectional view of the housing 1 shown in Figure 17. The housing 1 includes a first wall portion 13. The first pressure relief mechanism 31 and the second pressure relief mechanism 32 are both disposed on the first wall portion 13. The first wall portion 13 has a first outer surface 131 facing away from the electrode assembly 2 (not shown in Figures 17 and 18). The area of ​​the first outer surface 131 is S. The predetermined pressure relief area of ​​the first pressure relief mechanism 31 is S1, and the predetermined pressure relief area of ​​the second pressure relief mechanism 32 is S2, satisfying the following: 0.05≤(S1+S2) / S≤0.55.

[0227] The predetermined pressure relief area of ​​the first pressure relief mechanism 31 is the maximum area that the first pressure relief mechanism 31 is expected to be able to open; the predetermined pressure relief area of ​​the second pressure relief mechanism 32 is the maximum area that the second pressure relief mechanism 32 is expected to be able to open. It can be S1 = S2, S1 < S2, or S1 > S2.

[0228] Taking the first wall portion 13 as a rectangular wall portion as an example, the first outer surface 131 is a rectangle. The length and width of the first outer surface 131 are measured, and the area of ​​the first outer surface 131 can be calculated by multiplying the length and width of the first outer surface 131.

[0229] The first pressure relief mechanism 31 and the first wall portion 13 can be integrally formed or separately formed. The second pressure relief mechanism 32 and the first wall portion 13 can be integrally formed or separately formed. If the first pressure relief mechanism 31 and the first wall portion 13 are separately formed, a first pressure relief hole can be provided in the first wall portion 13, and the first pressure relief mechanism 31 can be mounted on the first wall portion 13 and cover the first pressure relief hole. If the second pressure relief mechanism 32 and the first wall portion 13 are separately formed, a second pressure relief hole can be provided in the first wall portion 13, and the second pressure relief mechanism 32 can be mounted on the second wall portion 14 and cover the second pressure relief hole.

[0230] As an example, in FIG18 , the housing 1 includes a first wall 13, a second wall 14, a third wall 15, and a fourth wall 16. The first wall 13, the third wall 15, the second wall 14, and the fourth wall 16 are connected end to end to form a housing 11 having openings at both ends. The third wall 15 has a second outer surface 151 facing away from the electrode assembly 2, and the fourth wall 16 has a third outer surface 161 facing away from the electrode assembly 2. The first outer surface 131 and the second outer surface 151 can be connected by a rounded surface, and the first outer surface 131 and the third outer surface 161 can be connected by another rounded surface.

[0231] In this embodiment, (S1+S2) / S 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.

[0232] In this embodiment, (S1+S2) / S≥0.05, so that the total pressure relief area of ​​the first pressure relief mechanism 31 and the second pressure relief mechanism 32 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) / S≤0.55, which is beneficial to improving the strength of the first wall portion 13.

[0233] In some embodiments, 0.15≤(S1+S2) / S≤0.35.

[0234] In this embodiment, (S1+S2) / S 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.

[0235] In some embodiments, please refer to FIG19 , which is a partial enlarged view of point C of the housing 1 shown in FIG18 . The first pressure relief mechanism 31 includes a first weak area 312 and a first pressure relief area 313 . The first pressure relief area 313 is configured to open when the first weak area 312 ruptures. The area of ​​the first pressure relief area 313 is S1 .

[0236] The first weak zone 312 is a weaker area in the first pressure relief mechanism 31. The first weak zone 312 can be formed in the first pressure relief mechanism 31 in a variety of ways. For example, a local area of ​​the first pressure relief mechanism 31 can be annealed to reduce the strength of the area, thereby forming the first weak zone 312. Another example is machining a groove in the first pressure relief mechanism 31 to form the first weak zone 312 in the area of ​​the groove.

[0237] The first pressure relief zone 313 may be an area defined by the first weak zone 312 . When the first weak zone 312 is broken, the first pressure relief zone 313 may be opened by flipping or detaching. The area of ​​the first pressure relief zone 313 is the predetermined pressure relief area of ​​the first pressure relief mechanism 31 .

[0238] In embodiments where the first pressure relief mechanism 31 is integrally formed with the first wall portion 13, the first weakened area 312 and the first pressure relief area 313 can be integrally formed with the first wall portion 13, thereby achieving integral formation of the first pressure relief mechanism 31 and the first wall portion 13. In embodiments where the first pressure relief mechanism 31 is provided separately from the first wall portion 13, the first pressure relief mechanism 31 can be a sheet-shaped explosion-proof disk, with the first weakened area 312 partially formed in the explosion-proof disk.

[0239] In this embodiment, when the first pressure relief mechanism 31 is opened, the first pressure relief area 313 can be opened with the first weak area 312 as a boundary, thereby increasing the pressure relief area of ​​the first pressure relief mechanism 31 .

[0240] In some embodiments, the first pressure relief mechanism 31 is provided with a first notch groove 311 , and the first pressure relief mechanism 31 forms a first weak area 312 in the area where the first notch groove 311 is provided.

[0241] In this embodiment, the first scored groove 311 can be a groove extending along a closed trajectory; the first scored groove 311 can also be a groove extending along a non-closed trajectory. The non-closed trajectory can be in the shape of an arc, U, H, V, L, Y, X, etc. After the first scored groove 311 is provided in the first pressure relief mechanism 31, the remaining portion of the first pressure relief mechanism 31 corresponding to the first scored groove 311 is the first weak zone 312.

[0242] In this embodiment, the first weak area 312 is formed by providing the first notch groove 311 on the first pressure relief mechanism 31 . The forming method of the first weak area 312 is simple, which reduces the difficulty of forming the first weak area 312 .

[0243] In some embodiments, please refer to FIG20 , which is a partial view of the first wall portion 13 provided in some embodiments of the present application. The first notched groove 311 is a groove extending along a closed trajectory, and the first notched groove 311 is disposed around the first pressure relief area 313 .

[0244] As an example, as shown in FIG20 , the first notch groove 311 includes two first arc segments 3111 and two first straight segments 3112. The two first straight segments 3112 are arranged in parallel. One first arc segment 3111, one first straight segment 3112, another first arc segment 3111, and another first straight segment 3112 are connected end to end. The central angle of the two first arc segments 3111 is 180°. The area of ​​the first pressure relief zone 313 (the predetermined pressure relief area of ​​the first pressure relief mechanism 31) is S1, S1 = a×b+π×a 2 Wherein, a is the distance between the inner side of one first straight line segment 3112 and the inner side of another first straight line segment 3112 , and b is the length of the first straight line segment 3112 . Both a and b can be measured on the surface where the notch of the first notch groove 311 is located.

[0245] In this embodiment, the first notched groove 311 is a groove extending along a closed trajectory. During the opening process of the first pressure relief mechanism 31, the first pressure relief area 313 can be separated from the shell 1, thereby increasing the pressure relief area of ​​the first pressure relief mechanism 31 and improving the pressure relief rate of the battery cell 10.

[0246] In some embodiments, please refer to Figures 21 and 22. Figure 21 is a partial view of the first wall portion 13 provided in some other embodiments of the present application; Figure 22 is a partial view of the first wall portion 13 provided in some other embodiments of the present application. The scored groove is a groove extending along a non-closed trajectory.

[0247] As an example, as shown in FIG21 , the first scored groove 311 is an H-shaped groove. The first scored groove 311 includes a second straight segment 3113 and two third straight segments 3114. The two third straight segments 3114 are arranged in parallel. One end of the second straight segment 3113 is connected to the midpoint of one third straight segment 3114, and the other end of the second straight segment 3113 is connected to the midpoint of the other third straight segment 3114. The area of ​​the first pressure relief zone 313 (the predetermined pressure relief area of ​​the first pressure relief mechanism 31) is S1, where S1 = 2×c×d. Here, c is the distance between the inner side of one third straight segment 3114 and the inner side of the other third straight segment 3114, and d is the distance between one end of the third straight segment 3114 and the side of the second straight segment 3113 facing the end. Both c and d can be measured from the surface where the notch of the first scored groove 311 is located.

[0248] As an example, as shown in FIG22 , first score groove 311 is a double Y-shaped groove. First score groove 311 includes a fourth straight segment 3115 and a fifth straight segment 3116. Two fifth straight segments 3116 are connected at both ends of fourth straight segment 3115 at a non-zero angle. Along the length of fourth straight segment 3115, the two fifth straight segments 3116 at one end of the fourth straight segment 3115 are symmetrically arranged with the two fifth straight segments 3116 at the other end of the fourth straight segment 3115. Along the width of fourth straight segment 3115, the two fifth straight segments 3116 on one side of the fourth straight segment 3115 are symmetrically arranged with the two fifth straight segments 3116 on the other side of the fourth straight segment 3115. Along the length of fourth straight segment 3115, the free ends of the two fifth straight segments 3116 are connected as a first line 3117. Along the width of fourth straight segment 3115, the free ends of the two fifth straight segments 3116 are connected as a second line 3118. The area of ​​the first pressure relief zone 313 (the predetermined pressure relief area of ​​the first pressure relief mechanism 31) is S1, where S1 = (f + g) × e + k × h. Here, f is the length of the fourth straight line segment 3115, g is the length of the first connecting line 3117, e is the distance between the first connecting line 3117 and the side of the fourth straight line segment 3115 facing the first connecting line 3117, k is the length of the second connecting line 3118, and h is the distance between the connecting point of the two fifth straight line segments 3116 located at the end of the fourth straight line segment 3115 facing the second connecting line 3118 and the second connecting line 3118. f, g, e, k, and h can all be measured on the surface where the notch of the first notch groove 311 is located.

[0249] In some embodiments, the second pressure relief mechanism 32 includes a second weak area and a second pressure relief area. The second pressure relief area is configured to open when the second weak area ruptures. The area of ​​the second pressure relief area is S2.

[0250] The second weak zone is a weaker area in the second pressure relief mechanism 32. The second weak zone can be formed in the second pressure relief mechanism 32 in a variety of ways. For example, a local area of ​​the second pressure relief mechanism 32 can be annealed to reduce the strength of the area to form the second weak zone. Another example is machining a groove in the second pressure relief mechanism 32 to form the second weak zone in the area of ​​the groove.

[0251] The thickness of the second weak area may be equal to or different from the thickness of the first weak area 312. For example, the thickness of the first weak area 312 is smaller than the thickness of the second weak area.

[0252] The second pressure relief zone may be an area defined by the second weak zone. When the second weak zone is broken, the second pressure relief zone may be opened by flipping or detaching. The area of ​​the second pressure relief zone is the predetermined pressure relief area of ​​the second pressure relief mechanism 32 .

[0253] In an embodiment where the second pressure relief mechanism 32 is integrally formed with the first wall portion 13, the second weak zone and the second pressure relief zone can be integrally formed with the first wall portion 13, thereby achieving integral formation of the second pressure relief mechanism 32 with the first wall portion 13. In an embodiment where the second pressure relief mechanism 32 is provided separately from the first wall portion 13, the second pressure relief mechanism 32 can be a sheet-shaped explosion-proof disk, with the explosion-proof disk partially forming the second weak zone.

[0254] When the second pressure relief mechanism 32 is opened, the second pressure relief area can be opened with the second weak area as the boundary, thereby increasing the pressure relief area of ​​the second pressure relief mechanism 32 .

[0255] In some embodiments, the second pressure relief mechanism 32 is provided with a second notch groove 321 , and the second pressure relief mechanism 32 forms a second weak zone in the area where the second notch groove 321 is provided.

[0256] In this embodiment, the second scored groove 321 can be a groove extending along a closed trajectory; the second scored groove 321 can also be a groove extending along a non-closed trajectory. After the second pressure relief mechanism 32 is provided with the first scored groove 311, the remaining portion of the second pressure relief mechanism 32 corresponding to the first scored groove 311 serves as the second weak zone.

[0257] In this embodiment, the second weak area is formed by providing the second notched groove 321 on the second pressure relief mechanism 32 . The second weak area is formed in a simple manner, which reduces the difficulty of forming the second weak area.

[0258] In some embodiments, the second notched groove 321 is a groove extending along a closed track, and the second notched groove 321 is disposed around the second pressure relief area.

[0259] In this embodiment, the shape of the second notch groove 321 can be the same as that of the first notch groove 311, the shape of the second pressure relief area can be the same as that of the first pressure relief area 313, and the calculation method of the second pressure relief area can be the same as that of the first pressure relief area 313, which will not be repeated here.

[0260] During the opening process of the second pressure relief mechanism 32 , the second pressure relief area can be separated from the housing 1 , thereby increasing the pressure relief area of ​​the second pressure relief mechanism 32 and improving the pressure relief rate of the battery cell 10 .

[0261] In some embodiments, the second score groove 321 is a groove extending along a non-closed trajectory.

[0262] In this embodiment, the second scored groove 321 can have the same shape as the first scored groove 311, for example, both being H-shaped grooves or double Y-shaped grooves. The shape of the second pressure relief area can also be the same as the shape of the first pressure relief area 313. The calculation method for the second pressure relief area can be the same as the calculation method for the first pressure relief area 313, and will not be repeated here.

[0263] In some embodiments, the predetermined pressure relief area of ​​the first pressure relief mechanism 31 is S1, and the predetermined pressure relief area of ​​the second pressure relief mechanism 32 is S2, satisfying: S1-S2≥50mm 2 .

[0264] S1-S2 can be 50mm 2 , 80mm 2 , 100mm 2 , 120mm 2 , 150mm 2 , 180mm 2 , 200mm 2 , etc. or any range of values ​​between them.

[0265] In this embodiment, S1-S2≥50mm 2 This facilitates the first pressure relief mechanism 31 opening before the second pressure relief mechanism 32. In the event of thermal runaway of the battery cell 10, pressure can be relieved first through the first pressure relief mechanism 31, which has a larger pressure relief area. This reduces the risk of a rapid increase in pressure or temperature within the housing 1 and improves the reliability of the battery cell 10.

[0266] In some embodiments, S1-S2≥100 mm 2 .

[0267] In this embodiment, S1-S2 can be 100mm 2 , 110mm 2 , 120mm 2 , 130mm 2 , 140mm 2 , 150mm 2 , 160mm 2 , 170mm 2 , 180mm 2 , 190mm 2 , 200mm 2 Any point value or any range of values ​​between the two.

[0268] An embodiment of the present application provides a battery 100 , comprising the battery cell 10 provided in any one of the above embodiments.

[0269] An embodiment of the present application provides an electrical device, comprising a battery cell 10 provided by any one of the above embodiments, and the battery cell 10 is used to provide electrical energy to the electrical device.

[0270] Referring to Figures 3 and 4 , an embodiment of the present application further provides a battery cell 10. The battery cell 10 includes a housing 1, an electrode assembly 2, a first pressure relief mechanism 31, and a second pressure relief mechanism 32. The electrode assembly 2 is housed within the housing 1. The first pressure relief mechanism 31 and the second pressure relief mechanism 32 are disposed on the housing 1, with the first pressure relief mechanism 31 opening earlier than the second pressure relief mechanism 32. The housing 1 includes a shell 11 and two end caps 12. The shell 11 has openings at opposite ends along a first direction X. The two end caps 12 respectively seal the openings at both ends of the shell 11. The electrode assembly 2 includes a main body 21 and tabs 22. Tabs 22 are disposed at opposite ends of the main body 21 along the first direction X. One end cap 12 is provided with a first electrode terminal 41, and the other end cap 12 is provided with a second electrode terminal 42. The tab 22 at one end of the main body 21 is electrically connected to the first electrode terminal 41, and the tab 22 at the other end of the main body 21 is electrically connected to the second electrode terminal 42. The shell 11 includes a first wall portion 13 and a second wall portion 14. The first wall portion 13 supports the main body portion 21 along the direction of gravity. The first pressure relief mechanism 31 and the second pressure relief mechanism 32 are both arranged on the first wall portion 13. A channel gap 17 is formed between the main body portion 21 and the second wall portion 14. The channel gap 17 is configured to connect the spaces inside the shell 1 at both ends of the main body portion 21 along the first direction X. The first direction X is perpendicular to the direction of gravity.

[0271] Referring to Figures 6 and 7 , an embodiment of the present application further provides a battery cell 10. The battery cell 10 includes a housing 1, an electrode assembly 2, a first pressure relief mechanism 31, and a second pressure relief mechanism 32. The electrode assembly 2 is housed within the housing 1. The first pressure relief mechanism 31 and the second pressure relief mechanism 32 are spaced apart from each other in the housing 1, with the first pressure relief mechanism 31 opening earlier than the second pressure relief mechanism 32. The housing 1 includes a shell 11 and two end caps 12. The shell 11 has openings at opposite ends along a first direction X, and the two end caps 12 respectively seal the openings at both ends of the shell 11. The electrode assembly 2 includes a main body 21 and tabs 22. Tabs 22 are provided at opposite ends of the main body 21 along the first direction X. One end cap 12 is provided with a first electrode terminal 41, and the other end cap 12 is provided with a second electrode terminal 42. The tab 22 at one end of the main body 21 is electrically connected to the first electrode terminal 41, and the tab 22 at the other end of the main body 21 is electrically connected to the second electrode terminal 42. The shell 11 includes a first wall portion 13 and a second wall portion 14 arranged opposite to each other. The first wall portion 13 supports the main body portion 21 along the direction of gravity. The first pressure relief mechanism 31 is arranged on the first wall portion 13, and the second pressure relief mechanism 32 is arranged on an end cover 12. A channel gap 17 is formed between the main body portion 21 and the second wall portion 14. The channel gap 17 is configured to connect the spaces inside the shell 1 at both ends of the main body portion 21 along the first direction X, where the first direction X is perpendicular to the direction of gravity.

[0272] Referring to FIG12 , an embodiment of the present application further provides a battery cell 10 comprising a housing 1, an electrode assembly 2, a first pressure relief mechanism 31, and a second pressure relief mechanism 32. The electrode assembly 2 is housed within the housing 1, and the first pressure relief mechanism 31 and the second pressure relief mechanism 32 are spaced apart from each other in the housing 1. The first pressure relief mechanism 31 is activated earlier than the second pressure relief mechanism 32. The housing 1 comprises a shell 11 and an end cap 12. The shell 11 has an opening at one end along a first direction X, and the end cap 12 seals the opening of the shell 11. The electrode assembly 2 (not shown in FIG12 ) comprises a main body 21 (not shown in FIG12 ) and a tab 22 (not shown in FIG12 ). Two tabs 22 are provided at the end of the main body 21 facing the end cap 12 along the first direction X. The end cap 12 is provided with a first electrode terminal 41 and a second electrode terminal 42. One tab 22 is electrically connected to the first electrode terminal 41, and the other tab 22 is electrically connected to the second electrode terminal 42. The shell 11 includes a first wall portion 13 , which is arranged opposite to the end cover 12 along the first direction X. The first wall portion 13 supports the main body 21 along the gravity direction. The first pressure relief mechanism 31 is arranged on the first wall portion 13 , and the second pressure relief mechanism 32 is arranged on the end cover 12 .

[0273] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0274] The above embodiments are intended only to illustrate the technical solutions of this application and are not intended to limit this application. Those skilled in the art will appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application are intended to be within the scope of protection of this application.

Claims

1. A battery cell, comprising: A housing for accommodating an electrode assembly; The first pressure relief mechanism and the second pressure relief mechanism are arranged at intervals on the housing, and the first pressure relief mechanism is opened earlier than the second pressure relief mechanism.

2. The battery cell according to claim 1, wherein: The opening pressure of the first pressure relief mechanism is P1, the opening pressure of the second pressure relief mechanism is P2, and P2-P1≥0.02Mpa.

3. The battery cell according to claim 2, wherein: 0.05Mpa≤P2-P1≤0.5Mpa.

4. The battery cell according to any one of claims 1 to 3, wherein: The housing includes a first wall portion, the first wall portion supports the electrode assembly along a gravity direction, and at least one of the first pressure relief mechanism and the second pressure relief mechanism is disposed on the first wall portion.

5. The battery cell according to claim 4, wherein: The first pressure relief mechanism is disposed on the first wall portion.

6. The battery cell according to claim 4 or 5, wherein: The housing comprises: A shell having openings formed at opposite ends; Two end covers, respectively closing the openings at both ends of the shell; The first wall portion is formed on the housing.

7. The battery cell according to claim 6, wherein: The first pressure relief mechanism and the second pressure relief mechanism are both arranged on the first wall portion.

8. The battery cell according to claim 6, wherein: One of the first pressure relief mechanism and the second pressure relief mechanism is disposed on the first wall portion, and the other is disposed on one of the end covers.

9. The battery cell according to any one of claims 6 to 8, wherein: The two end caps are arranged opposite to each other along a first direction, the electrode assembly comprises a main body and a tab, and the tab is arranged at least at one end of the main body along the first direction; The shell includes a second wall portion, which is arranged opposite to the first wall portion, and the first wall portion supports the main body along the direction of gravity. A channel gap is formed between the second wall portion and the main body, and the channel gap is configured to connect the space inside the shell located at both ends of the main body along the first direction, and the first direction intersects with the direction of gravity.

10. The battery cell according to claim 4 or 5, wherein: The housing comprises: A shell having an opening formed at one end; an end cap for closing the opening; Wherein, the end cover is the first wall portion; or, the wall portion of the shell body opposite to the end cover is the first wall portion.

11. The battery cell according to claim 10, wherein: One of the first pressure relief mechanism and the second pressure relief mechanism is arranged on the end cover, and the other is arranged on a wall portion of the housing opposite to the end cover.

12. The battery cell according to any one of claims 1 to 11, wherein: The housing comprises a shell and an end cover, and along a first direction, at least one end of the shell is formed with an opening, and the end cover corresponds to the opening one by one, and the end cover closes the opening; The shell has a first half area and a second half area, along the first direction, the portion from the middle section of the shell to one end of the shell is the first half area, the portion from the middle section of the shell to the other end of the shell is the second half area, and the middle section is perpendicular to the first direction; Wherein, the first pressure relief mechanism is arranged in the first half area, and the second pressure relief mechanism is arranged in the second half area.

13. The battery cell according to claim 12, wherein: Along the first direction, the length of the shell is L, and L≥80 mm.

14. The battery cell according to claim 12 or 13, wherein: Along the first direction, the shell has openings formed at two opposite ends, and the two end covers respectively close the openings at the two ends of the shell, and the two end covers are respectively located in the first half area and the second half area; The first pressure relief mechanism and the second pressure relief mechanism are respectively arranged on the two end covers; or, the first pressure relief mechanism and the second pressure relief mechanism are both arranged on the shell; or, the first pressure relief mechanism is arranged on the end cover located in the first half zone, and the second pressure relief mechanism is arranged on the part of the shell located in the second half zone; or, the first pressure relief mechanism is arranged on the part of the shell located in the first half zone, and the second pressure relief mechanism is arranged on the end cover located in the second half zone.

15. The battery cell according to claim 14, wherein: The battery cell further includes a first electrode terminal and a second electrode terminal with opposite polarities, the first electrode terminal and the second electrode terminal are both electrically connected to the electrode assembly, and the first electrode terminal and the second electrode terminal are respectively disposed on the two end caps.

16. The battery cell according to claim 12 or 13, wherein: The opening is formed at one end of the shell along the first direction, and one of the first pressure relief mechanism and the second pressure relief mechanism is disposed on the end cover, and the other is disposed on the shell.

17. The battery cell according to claim 16, wherein: Along the first direction, the housing includes a first wall portion disposed opposite to the end cover, one of the end cover and the first wall portion is located in the first half area, and the other is located in the second half area; One of the first pressure relief mechanism and the second pressure relief mechanism is disposed on the end cover, and the other is disposed on the first wall portion.

18. The battery cell according to claim 16 or 17, wherein: The battery cell further includes a first electrode terminal and a second electrode terminal with opposite polarities, the first electrode terminal and the second electrode terminal are both electrically connected to the electrode assembly, and the first electrode terminal and the second electrode terminal are both disposed on the end cap.

19. The battery cell according to any one of claims 1 to 7 and 10 to 13, wherein: The housing comprises a first wall portion, the first pressure relief mechanism and the second pressure relief mechanism are both arranged on the first wall portion, the first pressure relief mechanism is provided with a first notch groove, and the second pressure relief mechanism is provided with a second notch groove; The first notch groove and the second notch groove are spaced apart along a first direction. Along the first direction, the length of the shell is L, the maximum span of the first notch groove is L1, the maximum span of the second notch groove is L2, and 0.2≤(L1+L2) / L≤0.

6.

20. The battery cell according to any one of claims 1 to 7, 10 to 13 and 19, wherein: The shell includes a first wall portion, and the first pressure relief mechanism and the second pressure relief mechanism are both arranged on the first wall portion. The first wall portion has a first outer surface facing away from the electrode assembly, the area of ​​the first outer surface is S, the predetermined pressure relief area of ​​the first pressure relief mechanism is S1, and the predetermined pressure relief area of ​​the second pressure relief mechanism is S2, satisfying: 0.05≤(S1+S2) / S≤0.

55.

21. The battery cell according to claim 20, wherein: 0.15≤(S1+S2) / S≤0.

35.

22. The battery cell according to claim 20 or 21, wherein: The first pressure relief mechanism includes a first weak area and a first pressure relief area. The first pressure relief area is configured to be able to open when the first weak area is broken. The area of ​​the first pressure relief area is S1.

23. The battery cell according to claim 22, wherein: The first pressure relief mechanism is provided with a first notch groove, and the first pressure relief mechanism forms the first weak area in the area where the first notch groove is provided.

24. The battery cell according to claim 23, wherein: The first notched groove is a groove extending along a closed track, and the first notched groove is arranged around the first pressure relief area.

25. The battery cell according to any one of claims 20 to 24, wherein: The second pressure relief mechanism includes a second weak area and a second pressure relief area, the second pressure relief area is configured to be able to open when the second weak area is broken, and the area of ​​the second pressure relief area is S2.

26. The battery cell according to claim 25, wherein: The second pressure relief mechanism is provided with a second notch groove, and the second pressure relief mechanism forms the second weak area in the area where the second notch groove is provided.

27. The battery cell according to claim 26, wherein: The second notched groove is a groove extending along a closed track, and the second notched groove is arranged around the second pressure relief area.

28. The battery cell according to any one of claims 1 to 27, wherein: The predetermined pressure relief area of ​​the first pressure relief mechanism is S1, and the predetermined pressure relief area of ​​the second pressure relief mechanism is S2, satisfying: S1-S2≥50mm 2 .

29. The battery cell according to claim 28, wherein: S1-S2≥100mm 2 。 30. A battery comprising the battery cell according to any one of claims 1 to 29.

31. An electrical device, comprising a battery cell as claimed in any one of claims 1 to 29, wherein the battery cell is used to provide electrical energy to the electrical device.

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