Battery cell, battery and electric device

Abstract

The embodiments of the present application belong to the technical field of batteries. Provided are a battery cell, a battery and an electric device. The battery cell comprises a casing and an electrode assembly, wherein the casing comprises a first half area and a second half area; in the length direction of the casing, the part from a mid-cross section of the casing to one end of the casing is defined as the first half area, and the part from the mid-cross section of the casing to the other end of the casing is defined as the second half area; the length of the casing is L, with L≥80 mm; and the mid-cross section is perpendicular to the length direction. The electrode assembly is accommodated in the casing, and comprises a body portion and a tab, wherein the tab is provided at at least one end of the body portion in the length direction, with one part of the body portion being located in the first half area, and the other part thereof being located in the second half area. At least one pressure relief mechanism is provided in each of the first half area and the second half area; and the body portion is provided with a center hole, which penetrates the body portion in the length direction and is configured to bring an inner space of the first half area into communication with an inner space of the second half area. The reliability of the battery cell can be effectively improved.

Description

Battery cells, batteries and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application (2023111199910) 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, which includes a shell and an electrode assembly. The shell includes a first half-region and a second half-region. Along the length direction of the shell, the part from the middle cross-section of the shell to one end of the shell is the first half-region, and the part from the middle cross-section of the shell to the other end of the shell is the second half-region. The length of the shell is L, L≥80mm, and the middle cross-section is perpendicular to the length direction; the electrode assembly is accommodated in the shell, and the electrode assembly includes a main body and a pole ear. The main body is provided with a pole ear at least at one end along the length direction, a part of the main body is located in the first half-region, and the other part is located in the second half-region; wherein, the first half-region and the second half-region are both provided with at least one pressure relief mechanism, and the main body is provided with a center hole. The center hole passes through the main body along the length direction, and the center hole is used to connect the internal space of the first half-region with the internal space of the second half-region.

[0009] In the above technical solution, when the length of the housing is greater than or equal to 80 mm, pressure relief mechanisms are provided in both the first and second half regions. In the event of thermal runaway of a battery cell, pressure relief can be provided through the pressure relief mechanisms in the first and second half regions. This allows the exhaust medium in the first half region of the housing to be discharged more quickly through the pressure relief mechanism in the first half region, and the exhaust medium in the second half region of the housing to be discharged more quickly through the pressure relief mechanism in the second half region, thereby improving the timeliness of pressure relief in the battery cell and effectively improving the reliability of the battery cell. The central hole in the main body can serve as a flow channel for the exhaust medium within the housing. Exhaust medium at one end of the main body can be discharged through the pressure relief mechanism in the first half region, or it can flow through the central hole to the other end of the main body and be discharged through the pressure relief mechanism in the second half region, thereby improving the timeliness of pressure relief in the battery cell.

[0010] In some embodiments, the housing comprises a first end wall, a second end wall, and a side wall. The first end wall is located in the first half, and the second end wall is located in the second half. The first and second end walls are disposed opposite each other along the length direction, and the side wall surrounds the first and second end walls. Each of the first and second end walls is provided with at least one pressure relief mechanism. Furthermore, both the portion of the side wall located in the first half and the portion of the side wall located in the second half are provided with at least one pressure relief mechanism. Furthermore, both the portion of the side wall located in the first half and the second end wall are provided with at least one pressure relief mechanism. Furthermore, both the portion of the side wall located in the second half and the first end wall are provided with at least one pressure relief mechanism. If both the first and second end walls are provided with at least one pressure relief mechanism, the exhaust medium within the housing can be discharged from both ends of the housing, allowing the exhaust medium accumulated at both ends of the electrode assembly within the housing to be quickly discharged, thereby improving the reliability of the battery cells. If both the portion of the side wall located in the first half and the portion of the side wall located in the second half are provided with a pressure relief mechanism, the exhaust medium within the housing can be discharged from the sides of the housing, reducing the risk of the exhaust medium damaging external components connected to the ends of the battery cells. If the portion of the side wall located in the first half zone and the second end wall are both provided with a pressure relief mechanism, the discharge medium inside the shell can be discharged from the side and end of the shell, thereby improving the timeliness of the pressure relief of the battery cell; if the portion of the side wall located in the second half zone and the first end wall are both provided with a pressure relief mechanism, the discharge medium inside the shell can also be discharged from the side and end of the shell, thereby improving the timeliness of the pressure relief of the battery cell.

[0011] In some embodiments, the sidewall includes a first wall portion and a second wall portion disposed opposite each other, the first wall portion being configured to support the main body portion in the direction of gravity, and a channel gap being formed between the second wall portion and the main body portion, the channel gap being configured to connect spaces within the housing located at both ends of the main body portion along the length direction. Because the channel gap is formed between the first wall portion and the main body portion, and because the channel gap connects spaces within the housing located at both ends of the main body portion along the length direction, in the event of thermal runaway of a battery cell, if the pressure relief mechanism of the first half section is unable to promptly relieve pressure, the exhaust medium near the pressure relief mechanism of the first half section can flow through the channel gap to the pressure relief mechanism of the second half section for discharge through the pressure relief mechanism. Similarly, if the pressure relief mechanism of the second half section is unable to promptly relieve pressure, the exhaust medium near the pressure relief mechanism of the second half section can flow through the channel gap to the pressure relief mechanism of the first half section for discharge through the pressure relief mechanism.

[0012] In some embodiments, the first wall portion is provided with at least one pressure relief mechanism, so that when the battery cell experiences thermal runaway, the exhaust medium inside the housing can be discharged from the bottom of the battery cell.

[0013] In some embodiments, the first wall is provided with multiple pressure relief mechanisms, including a first pressure relief mechanism and a second pressure relief mechanism provided on the first wall, the first pressure relief mechanism being located in the first half region, and the second pressure relief mechanism being located in the second half region. If the thermal runaway region of the main body of the electrode assembly is located in the first half region, a large amount of exhaust medium may accumulate near the first pressure relief mechanism. If the exhaust medium cannot be discharged promptly through the first pressure relief mechanism, the exhaust medium may flow through the channel gap to the second pressure relief mechanism and be discharged through the second pressure relief mechanism, thereby improving the timeliness of pressure relief of the battery cells. If the thermal runaway region of the main body of the electrode assembly is located in the second half region, a large amount of exhaust medium may accumulate near the second pressure relief mechanism. If the exhaust medium cannot be discharged promptly through the second pressure relief mechanism, the exhaust medium may flow through the channel gap to the first pressure relief mechanism and be discharged through the first pressure relief mechanism, thereby improving the timeliness of pressure relief of the battery cells.

[0014] In some embodiments, the first pressure relief mechanism and the second pressure relief mechanism are symmetrically arranged about the mid-section of the housing. This ensures that the pressure relief areas of the first and second pressure relief mechanisms are equal, and the distances from the mid-section of the housing to the first and second pressure relief mechanisms along the length direction are equal. This allows both the first and second pressure relief mechanisms to provide effective pressure relief in the event of thermal runaway of the battery cells.

[0015] In some embodiments, the multiple pressure relief mechanisms further include a third pressure relief mechanism disposed on the first wall, with a portion of the third pressure relief mechanism located in the first half and another portion located in the second half. Thus, the central region of the first wall is also provided with a pressure relief mechanism, which facilitates the discharge of the exhaust medium located in the central region of the housing and improves the timeliness of pressure relief for the battery cells.

[0016] In some embodiments, at least one pressure relief mechanism is provided on the sidewall, with a portion of the at least one pressure relief mechanism located in the first half and another portion located in the second half. Thus, not only are pressure relief mechanisms provided in the first and second halves of the housing, but also in the middle region of the sidewall, which can improve the timeliness of pressure relief from the battery cells.

[0017] In some embodiments, the sidewall is provided with multiple pressure relief mechanisms, including a first pressure relief mechanism, a second pressure relief mechanism, and a third pressure relief mechanism. The first pressure relief mechanism is located in the first half, the second pressure relief mechanism is located in the second half, and a portion of the third pressure relief mechanism is located in the first half and the remaining portion is located in the second half. With the first, second, and third pressure relief mechanisms provided on the sidewall, the exhaust medium in the two end areas of the internal space of the housing can be discharged through the first and second pressure relief mechanisms, respectively, while the exhaust medium in the central area can be discharged through the third pressure relief mechanism, thereby improving the timeliness of pressure relief of the battery cells.

[0018] In some embodiments, the housing includes a shell and two end caps; the shell has openings at opposite ends along its length; the two end caps respectively seal the openings at both ends of the shell; the two end caps are respectively a first end wall and a second end wall. The shell is a hollow structure with openings at both ends, and the electrode assembly can be inserted into the shell through either end opening, which can improve the efficiency of inserting the electrode assembly into the shell.

[0019] In some embodiments, the housing includes a shell and an end cap; the shell has an opening formed at one end along its length; the end cap closes the opening; the end cap is a first end wall, and the wall of the shell opposite the end cap along its length is a second end wall. The shell is a hollow structure with an opening formed at one end, and the electrode assembly is accommodated within the shell. The end cap closes the shell opening to complete the assembly of the battery cell, effectively reducing the difficulty of battery cell assembly.

[0020] In some embodiments, the housing includes a first wall portion, the first wall portion being provided with a plurality of pressure relief mechanisms spaced apart along the length, each pressure relief mechanism being provided with a scored groove. Along the length, the sum of the maximum spans of the scored grooves of the plurality of pressure relief mechanisms is L1, satisfying the following: 0.2 ≤ L1 / L ≤ 0.6. L1 / L ≥ 0.2, thereby increasing the sum of the maximum spans of the scored grooves of the plurality of pressure relief mechanisms on the first wall portion along the length, thereby increasing the total pressure relief area of ​​the plurality of pressure relief mechanisms on the first wall portion, and thereby facilitating an improvement in the pressure relief rate of the battery cells. L1 / L ≤ 0.6, thereby limiting the sum of the maximum spans of the scored grooves of the plurality of pressure relief mechanisms on the first wall portion along the length, and thereby facilitating an improvement in the strength of the first wall portion.

[0021] In some embodiments, the battery cell further includes a support member disposed within the central hole and supported by the wall of the central hole. The provision of the support member can reduce the risk of central hole collapse. On the one hand, it can keep the central hole unobstructed, allowing the discharge medium at one end of the main body to flow through the central hole to the other end of the main body. On the other hand, it can reduce the risk of lithium deposition caused by central hole collapse.

[0022] In some embodiments, the support member is an adhesive layer adhered to the wall surface of the central hole. The support member is not easily separated from the wall surface of the central hole, and the support member can better support and strengthen the central hole.

[0023] In some embodiments, an electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. The separator is disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, separator, and negative electrode sheet are wound to form a wound structure. The separator defines a central hole, and the support member is connected to the separator. Thus, before the electrode assembly is formed, the support member can be connected to the separator. After the positive electrode sheet, separator, and negative electrode sheet are wound to form the electrode assembly, the support member is located within the central hole and supports the wall surface of the central hole. This reduces the difficulty of arranging the support member within the central hole.

[0024] In some embodiments, the diameter of the central hole is D, satisfying the following conditions: 3 mm ≤ D ≤ 8 mm. D ≥ 3 mm allows the central hole to have a larger diameter, enabling the discharge medium located at one end of the main body within the housing to flow more quickly through the central hole to the other end of the main body. D ≤ 8 mm prevents the central hole from being too large, reducing the risk of the central hole collapsing.

[0025] In some embodiments, the battery cell further includes an electrode terminal and a current collecting member. The electrode terminal is disposed on the housing, and the current collecting member is disposed on a side of the main body facing the electrode terminal. The current collecting member connects the electrode terminal and the tab. The current collecting member is provided with a first through hole that communicates with the central hole. This prevents the current collecting member from blocking the central hole, allowing the discharged medium entering the central hole to flow smoothly to the pressure relief mechanism.

[0026] In some embodiments, along the length direction, the projection of the hole wall of the first through hole is at least partially located inside the central hole, thereby reducing the obstruction of the flow collecting member on the discharge medium in the central hole, so that the discharge medium in the central hole can quickly flow through the first through hole to the pressure relief mechanism.

[0027] In some embodiments, the pressure relief mechanism is integrally formed with the corresponding wall portion of the housing. This increases the reliability of the pressure relief mechanism, eliminates the need for a connection process between the pressure relief mechanism and the housing, and reduces the production cost of the battery cell.

[0028] In some embodiments, the pressure relief mechanism is provided separately from the housing, the housing is provided with a pressure relief hole, and the pressure relief mechanism is mounted on the housing and covers the pressure relief hole. The pressure relief mechanism is a component independent of the housing, and the pressure relief mechanism and the housing can be manufactured and assembled separately, which reduces production difficulty and improves efficiency.

[0029] In some embodiments, the housing is in the shape of a rectangular parallelepiped.

[0030] In some embodiments, the housing is cylindrical, and the axial direction of the housing is parallel to the length direction.

[0031] In some embodiments, L is greater than or equal to 160 mm. When the length of the housing is greater than or equal to 160 mm, it is more difficult to timely release pressure from the battery cells in the event of thermal runaway. However, providing pressure relief mechanisms in both the first and second half areas of the housing can alleviate the problem of delayed pressure relief from the battery cells.

[0032] 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.

[0033] 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

[0034] 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.

[0035] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0036] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0037] FIG3 is an axonometric view of a battery cell (with a rectangular outer shell) provided in some embodiments of the present application;

[0038] FIG4 is an exploded view of the battery cell shown in FIG3 ;

[0039] FIG5 is a view of the battery cell shown in FIG3 taken along the direction of arrow A;

[0040] FIG6 is an axonometric view of a battery cell (with a rectangular outer shell) provided in some other embodiments of the present application;

[0041] FIG7 is an exploded view of the battery cell shown in FIG6 ;

[0042] FIG8 is an axonometric view of a battery cell (with a rectangular outer shell) provided in some other embodiments of the present application;

[0043] FIG9 is an axonometric view of a battery cell (with a rectangular outer shell) provided in some other embodiments of the present application;

[0044] FIG10 is a cross-sectional view of a battery cell (with a rectangular outer shell) provided in some embodiments of the present application;

[0045] FIG11 is a cross-sectional view of a battery cell (with a rectangular outer shell) provided in some other embodiments of the present application;

[0046] FIG12 is an axonometric view of a battery cell (with a cylindrical housing) provided in some embodiments of the present application;

[0047] FIG13 is an exploded view of a battery cell (with a cylindrical housing) provided in some embodiments of the present application;

[0048] FIG14 is an axonometric view of a battery cell (with a cylindrical outer shell) provided in some other embodiments of the present application;

[0049] FIG15 is a cross-sectional view of a battery cell (with a cylindrical housing) provided in some embodiments of the present application;

[0050] FIG16 is an axonometric view of a housing provided in some embodiments of the present application;

[0051] FIG17 is a cross-sectional view of the housing shown in FIG16 taken along the XY plane;

[0052] FIG18 is an enlarged view of the housing shown in FIG17 at position B;

[0053] FIG19 is a partially enlarged view of the housing provided in some other embodiments of the present application.

[0054] Icons: 1-housing; 11-shell; 12-end cover; 13-first half; 14-second half; 15-first end wall; 16-second end wall; 17-side wall; 171-first wall portion; 172-second wall portion; 173-third wall portion; 174-fourth wall portion; 175-score groove; 176-weak area; 177-pressure relief hole; 2-electrode assembly; 21-main body; 211-center hole; 22-electrode ear; 3-pressure relief mechanism; 3a-first pressure relief mechanism; 3b-second Pressure relief mechanism; 3c-third pressure relief mechanism; 31-pressure relief zone; 4-electrode terminal; 5-channel gap; 51-first space; 52-second space; 6-connecting block; 7-support member; 8-current collecting member; 81-first through hole; 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-length direction. DETAILED DESCRIPTION

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] The term "plurality" used in this application refers to two or more (including two).

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.).

[0067] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0068] 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.

[0069] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0070] 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.).

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical and mechanical stability.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0082] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0083] 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.

[0084] 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.

[0085] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0086] 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.

[0087] In some embodiments, the electrode assembly is a laminate structure.

[0088] 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.

[0089] 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.

[0090] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0091] 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.

[0092] 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.

[0093] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0102] 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.

[0103] 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.

[0104] In a typical battery cell, the outer shell of the battery cell is equipped with only one pressure relief mechanism, located at one end of the outer shell along its length. In the event of thermal runaway of the battery cell, the pressure relief mechanism releases the exhaust medium inside the outer shell to relieve the pressure inside the battery cell. However, when the length of the battery cell outer shell is greater than or equal to 80 mm, the exhaust medium in the half of the outer shell near the pressure relief mechanism can flow quickly to the pressure relief mechanism along the length of the outer shell, but the exhaust medium in the half of the outer shell far from the pressure relief mechanism has difficulty flowing to the pressure relief mechanism. This can easily lead to delayed pressure relief and poor reliability of the battery cell.

[0105] In view of this, an embodiment of the present application provides a battery cell, in which, when the length of the shell is greater than or equal to 80 mm, the shell is divided into a first half zone and a second half zone. Along the length direction of the shell, the part from the middle cross-section of the shell to one end of the shell is the first half zone, and the part from the middle cross-section of the shell to the other end of the shell is the second half zone, and at least one pressure relief mechanism is provided in both the first half zone and the second half zone.

[0106] In such a battery cell, when the battery cell thermally runs away, pressure relief can be performed through the pressure relief mechanism of the first half zone and the pressure relief mechanism of the second half zone, so that the emission medium in the first half zone within the shell can be discharged more quickly through the pressure relief mechanism of the first half zone, and the emission medium in the second half zone within the shell can be discharged more quickly through the pressure relief mechanism of the second half zone, thereby improving the timeliness of pressure relief of the battery cell and effectively improving the reliability of the battery cell.

[0107] The battery cells described in the embodiments of the present application are suitable for batteries and electrical equipment using the battery cells.

[0108] 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.

[0109] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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 also 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.

[0115] 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.

[0116] 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.

[0117] 3 and 4 , FIG3 is an isometric view of a battery cell 10 provided in some embodiments of the present application; FIG4 is an exploded view of the battery cell 10 shown in FIG3 . The battery cell 10 may include a housing 1 , an electrode assembly 2 , and a pressure relief mechanism 3 .

[0118] 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 .

[0119] 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.

[0120] The end cap 12 is a component that closes the opening of the shell 11 to isolate the internal environment of the battery cell 10 from the external environment. The end cap 12 and the shell 11 together define a storage space for accommodating the electrode assembly 2, electrolyte and other components. The shape of the end cap 12 can be adapted to the shape of the shell 1. For example, the shell 11 is a rectangular parallelepiped structure, and the end cap 12 is a rectangular plate structure adapted to the shell 1. For another example, the shell 11 is a cylindrical structure, and the end cap 12 is a circular plate structure adapted to the shell 11. The material of the end cap 12 can also be a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, plastic, etc. The material of the end cap 12 and the shell 11 can be the same or different.

[0121] 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.

[0122] The pressure relief mechanism 3 is a component that releases pressure from the battery cell 10. When the internal pressure of the battery cell 10 reaches a threshold, the pressure relief mechanism 3 discharges the exhaust medium from the battery cell 10 to achieve the purpose of pressure relief. Exhaust media include, but are not limited to, electrolyte, dissolved or split positive and negative electrode sheets, separator fragments, reaction gases, flames, etc. The pressure relief mechanism 3 can be located in the housing 11 or the end cap 12.

[0123] 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 8.

[0124] As an example, as shown in Figure 4, the shell 11 is a hollow structure with openings formed at opposite ends. End covers 12 are provided at the opposite ends of the shell 11. Electrode terminals 4 are provided on the end covers 12 at both ends of the shell 11. Pole ears 22 are formed at the opposite ends of the electrode assembly 2. The pole ear 22 at one end of the electrode assembly 2 is a positive pole ear, and the pole ear 22 at the other end of the electrode assembly 2 is a negative pole ear. The electrode terminal 4 on one end cover 12 is electrically connected to the positive pole ear, and the electrode terminal 4 on the other end cover 12 is electrically connected to the negative pole ear.

[0125] Please refer to Figures 3 to 5. Figure 5 is a view of the battery cell 10 shown in Figure 3 taken along the direction A. This embodiment of the present application provides a battery cell 10, comprising a housing 1. The housing 1 comprises a first half region 13 and a second half region 14. Along the length direction Z of the housing 1, the portion from the mid-section W of the housing 1 to one end of the housing 1 constitutes the first half region 13, and the portion from the mid-section W of the housing 1 to the other end of the housing 1 constitutes the second half region 14. The length of the housing 1 is L, L ≥ 80 mm, and the mid-section W is perpendicular to the length direction Z. The first half region 13 and the second half region 14 are both provided with a pressure relief mechanism 3.

[0126] The housing 1 may be cylindrical, prismatic, or the like. The prism may be a triangular prism, a quadrangular prism, a pentagonal prism, a hexagonal prism, or the like. The quadrangular prism may include a rectangular parallelepiped, a cube, or the like. In embodiments where the housing 1 is cylindrical, the axial direction of the housing 1 is the longitudinal direction Z of the housing 1 . In embodiments where the housing 1 is a rectangular parallelepiped, the length of the housing 1 is greater than or equal to the height and width of the housing 1 .

[0127] It is understood that along the length direction Z of the housing 1, the midsection W is located in the middle of the housing, and the distance from the midsection W to both ends of the housing 1 is equal. Along the length direction Z of the housing 1, the housing 1 has two opposing end surfaces, the maximum distance between the two end surfaces being the length of the housing 1, and the distance from the midsection W to the two end surfaces is 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 protrusion or a recess, the length of the housing 1 is measured based on the planar area of ​​the end surface. In embodiments where the housing 11 is a hollow structure with an opening at one end along the length direction Z, the surface of the end cap 12 facing the exterior of the housing 1 may be one end surface of the housing 1, and the surface of the wall of the housing 11 opposing the end cap 12 facing the exterior of the housing 1 may be the other end surface of the housing 1. In embodiments where the housing 11 is a hollow structure with openings at both opposing ends along the length direction Z, the surface of one end cap 12 facing the exterior of the housing 1 may be one end surface of the housing 1, and the surface of the other end cap 12 facing the exterior of the housing 1 may be the other end surface of the housing 1.

[0128] The first half section 13 may be provided with one or more pressure relief mechanisms 3; the second half section 14 may be provided with one or more pressure relief mechanisms 3. The pressure relief mechanism 3 may be part of the housing 1 or a separate component from the housing 1. It is understood that the pressure relief mechanism 3 provided in the first half section 13 is entirely located in the first half section 13, while the pressure relief mechanism 3 provided in the second half section 14 is entirely located in the second half section 14.

[0129] In this embodiment, L can be any one 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.

[0130] In an embodiment of the present application, when the length of the outer shell 1 is greater than or equal to 80 mm, a pressure relief mechanism 3 is provided in both the first half zone 13 and the second half zone 14. When the battery cell 10 thermally runs away, pressure relief can be performed through the pressure relief mechanism 3 of the first half zone 13 and the pressure relief mechanism 3 of the second half zone 14, so that the emission medium in the first half zone 13 of the outer shell 1 can be discharged more quickly through the pressure relief mechanism 3 of the first half zone 13, and the emission medium in the second half zone 14 of the outer shell 1 can be discharged more quickly through the pressure relief mechanism 3 of the second half zone 14, thereby shortening the path of the emission medium in the outer shell 1 to flow to the pressure relief mechanism 3, improving the timeliness of pressure relief of the battery cell 10, and thereby effectively improving the reliability of the battery cell 10.

[0131] In some embodiments, referring to Figures 3-9 , Figure 6 is an isometric view of a battery cell 10 (housing 1 is a rectangular parallelepiped) provided in other embodiments of the present application; Figure 7 is an exploded view of the battery cell 10 shown in Figure 6 ; Figure 8 is an isometric view of a battery cell 10 (housing 1 is a rectangular parallelepiped) provided in still other embodiments of the present application; and Figure 9 is an isometric view of a battery cell 10 (housing 1 is a rectangular parallelepiped) provided in still other embodiments of the present application. The housing 1 has a first end wall 15 , a second end wall 16 , and side walls 17 . The first end wall 15 is located in the first half 13 , and the second end wall 16 is located in the second half 14 . The first end wall 15 and the second end wall 16 are disposed opposite each other along the longitudinal direction Z of the housing 1 , and the side walls 17 surround the first end wall 15 and the second end wall 16 .

[0132] The first end wall 15 and the second end wall 16 are both provided with at least one pressure relief mechanism 3; and / or, the portion of the side wall 17 located in the first half area 13 and the portion of the side wall 17 located in the second half area 14 are both provided with at least one pressure relief mechanism 3; and / or, the portion of the side wall 17 located in the first half area 13 and the second end wall 16 are both provided with at least one pressure relief mechanism 3; and / or, the portion of the side wall 17 located in the second half area 14 and the first end wall 15 are both provided with at least one pressure relief mechanism 3.

[0133] The first end wall 15 and the second end wall 16 are two opposing walls of the housing 1 along the longitudinal direction Z. The first end wall 15 can be the end cap 12, and the second end wall 16 and side wall 17 can be integrally formed to form the housing 11. Alternatively, the second end wall 16 can be the end cap 12, and the first end wall 15 and side wall 17 can be integrally formed to form the housing 11. Alternatively, both the first end wall 15 and the second end wall 16 can be the end cap 12, and the side wall 17 can be the housing 11. It is understood that a portion of the side wall 17 is located in the first half 13, and another portion of the side wall 17 is located in the second half 14. In embodiments where the housing 1 is rectangular, both the first end wall 15 and the second end wall 16 can be rectangular plate-like structures, and the side wall 17 can be a hollow rectangular structure. In embodiments where the housing 1 is cylindrical, both the first end wall 15 and the second end wall 16 can be circular plate-like structures, and the side wall 17 can be a hollow cylindrical structure.

[0134] In an embodiment in which the portion of the side wall 17 located in the first half 13 and the portion of the side wall 17 located in the second half 14 are both provided with a pressure relief mechanism 3, the portion of the side wall 17 located in the first half 13 may be provided with one or more pressure relief mechanisms 3, the portion of the side wall 17 located in the second half 14 may be provided with one or more pressure relief mechanisms 3, and the first end wall 15 and the second end wall 16 may be provided with a pressure relief mechanism 3 or not. As an example, as shown in Figures 3 and 4, the portion of the side wall 17 located in the first half 13 and the portion of the side wall 17 located in the second half 14 are both provided with a pressure relief mechanism 3, while the first end wall 15 and the second end wall 16 are not provided with a pressure relief mechanism 3.

[0135] In the embodiment where both the first end wall 15 and the second end wall 16 are provided with a pressure relief mechanism 3, the first end wall 15 may be provided with one or more pressure relief mechanisms 3; the second end wall 16 may be provided with one or more pressure relief mechanisms 3; and the housing 11 may be provided with a pressure relief mechanism 3 or not. As an example, as shown in Figures 6 and 7, both the first end wall 15 and the second end wall 16 are provided with a pressure relief mechanism 3, while the housing 11 is not provided with a pressure relief mechanism 3.

[0136] In the embodiment where the portion of the side wall 17 located in the first half 13 and the second end wall 16 are both provided with a pressure relief mechanism 3, the portion of the side wall 17 located in the first half 13 may be provided with one or more pressure relief mechanisms 3, the second end wall 16 may be provided with one or more pressure relief mechanisms 3, and the portion of the side wall 17 located in the second half 14 and the first end wall 15 may or may not be provided with a pressure relief mechanism 3. As an example, as shown in FIG8 , the portion of the side wall 17 located in the first half 13 and the second end wall 16 are both provided with a pressure relief mechanism 3, while the portion of the side wall 17 located in the second half 14 and the first end wall 15 are not provided with a pressure relief mechanism 3.

[0137] In the embodiment where the portion of the side wall 17 located in the second half 14 and the first end wall 15 are both provided with a pressure relief mechanism 3, the portion of the side wall 17 located in the second half 14 may be provided with one or more pressure relief mechanisms 3, the first end wall 15 may be provided with one or more pressure relief mechanisms 3, and the portion of the side wall 17 located in the first half 13 and the second end wall 16 may or may not be provided with a pressure relief mechanism 3. As an example, as shown in FIG9 , the portion of the side wall 17 located in the second half 14 and the first end wall 15 are both provided with a pressure relief mechanism 3, while the portion of the side wall 17 located in the first half 13 and the second end wall 16 are not provided with a pressure relief mechanism 3.

[0138] If both the first end wall 15 and the second end wall 16 are provided with a pressure relief mechanism 3, in the event of thermal runaway of the battery cell 10, the exhaust medium within the housing 1 can be discharged from both ends of the housing 1, allowing the exhaust medium accumulated within the housing 1 at both ends of the electrode assembly 2 to be quickly discharged, thereby improving the reliability of the battery cell 10. If both the portion of the side wall 17 located in the first half region 13 and the portion of the side wall 17 located in the second half region 14 are provided with a pressure relief mechanism 3, the exhaust medium within the housing 1 can be discharged from the side of the housing 1, reducing the risk of the exhaust medium damaging external components connected to the ends of the battery cell 10. These external components may include a busbar connected to the electrode terminal 4, a temperature sensing element, a voltage sensing element, and the like. If the portion of the side wall 17 located in the first half zone 13 and the second end wall 16 are both provided with a pressure relief mechanism 3, the discharge medium inside the shell 1 can be discharged from the side and end of the shell 1, thereby improving the timeliness of the pressure relief of the battery cell 10; if the portion of the side wall 17 located in the second half zone 14 and the first end wall 15 are both provided with a pressure relief mechanism 3, the discharge medium inside the shell 1 can also be discharged from the side and end of the shell 1, thereby improving the timeliness of the pressure relief of the battery cell 10.

[0139] In some embodiments, please refer to FIG10 , which is a cross-sectional view of a battery cell 10 (housing 1 is a rectangular parallelepiped) provided in some embodiments of the present application. Battery cell 10 also includes an electrode assembly 2, which is housed within housing 1. Electrode assembly 2 includes a main body 21 and a tab 22. Main body 21 is provided with tab 22 at at least one end along the longitudinal direction Z of housing 1. A portion of main body 21 is located in first half 13, and another portion is located in second half 14. Sidewall 17 includes a first wall 171 and a second wall 172 disposed opposite each other. First wall 171 is configured to support main body 21 in the direction of gravity. A channel gap 5 is formed between second wall 172 and main body 21. Channel gap 5 is configured to connect the spaces within housing 1 located at both ends of main body 21 along the longitudinal direction Z of housing 1.

[0140] Along the length direction Z of the housing 1, the main body 21 can be provided with a tab 22 at one end, or at both ends. As an example, in Figure 10, the main body 21 is provided with a tab 22 at both ends, with the tab 22 at one end being the positive tab and the tab 22 at the other end being the negative tab. Both the first end wall 15 and the second end wall 16 are provided with an electrode terminal 4. The electrode terminal 4 on the first end wall 15 is electrically connected to the tab 22 at one end of the main body 21, and the electrode terminal 4 on the second end wall 16 is electrically connected to the tab 22 at the other end of the main body 21.

[0141] 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.

[0142] The first wall 171 and the second wall 172 are two opposing walls of the side wall 17. The first wall 171 is the wall portion of the side wall 17 that supports the main body 21 in the direction of gravity. The first wall 171 bears the gravity of the main body 21. The first wall 171 and the second wall 172 are arranged opposite each other in the direction of gravity of the main body 21. The thickness of the first wall 171 and the second wall 172 can be equal or different, for example, the thickness of the first wall 171 is greater than the thickness of the second wall 172. The first wall 171 can directly contact the main body 21 to support the main body 21, or an intermediate member can be provided between the first wall 171 and the main body 21, so that the first wall 171 supports the main body 21 through the intermediate member. The intermediate member can be an insulating member provided between the first wall 171 and the main body 21.

[0143] A channel gap 5 is formed between the second wall portion 172 and the main body 21. Inside the housing 1, along the longitudinal direction Z of the housing 1, the spaces at either end of the main body 21 are a first space 51 and a second space 52, respectively. The channel gap 5 connects the first space 51 and the second space 52. The first space 51 is located in the first half 13, and the second space 52 is located in the second half 14. In the event of thermal runaway of the battery cell 10, the exhaust medium from one of the first and second spaces 51, 52 can flow to the other through the channel gap 5.

[0144] In this embodiment, since a channel gap 5 is formed between the first wall portion 171 and the main body portion 21, and the channel gap 5 is connected to the space inside the shell 1 located at both ends of the main body portion 21 along the length direction Z of the shell 1, when the battery cell 10 thermally runs away, if the pressure relief mechanism 3 of the first half area 13 cannot release pressure in time, the discharge medium near the pressure relief mechanism 3 of the first half area 13 can flow through the channel gap 5 to the pressure relief mechanism 3 of the second half area 14 to be discharged through the pressure relief mechanism 3; similarly, if the pressure relief mechanism 3 of the second half area 14 cannot release pressure in time, the discharge medium near the pressure relief mechanism 3 of the second half area 14 can flow through the channel gap 5 to the pressure relief mechanism 3 of the first half area 13 to be discharged through the pressure relief mechanism 3.

[0145] In some embodiments, please continue to refer to FIG. 10 , the first wall portion 171 is provided with at least one pressure relief mechanism 3 .

[0146] The first wall portion 171 may be provided with one pressure relief mechanism 3 or multiple pressure relief mechanisms 3 .

[0147] When the battery cell 10 thermally runs away, the exhaust medium inside the housing 1 may be discharged from the bottom of the battery cell 10 .

[0148] In some embodiments, please continue to refer to Figure 10. The first wall portion 171 is provided with multiple pressure relief mechanisms 3. The multiple pressure relief mechanisms 3 include a first pressure relief mechanism 3a and a second pressure relief mechanism 3b provided on the first wall portion 171. The first pressure relief mechanism 3a is located in the first half area 13, and the second pressure relief mechanism 3b is located in the second half area 14.

[0149] It is possible that only two pressure relief mechanisms 3 are provided on the first wall portion 171, and the two pressure relief mechanisms 3 are respectively the first pressure relief mechanism 3a and the second pressure relief mechanism 3b; it is also possible that three or more pressure relief mechanisms 3 are provided on the first wall portion 171, and the two pressure relief mechanisms 3 are respectively the first pressure relief mechanism 3a and the second pressure relief mechanism 3b.

[0150] In this embodiment, if the thermal runaway area of ​​the main body 21 of the electrode assembly 2 is located in the first half zone 13, a large amount of discharge medium will accumulate near the first pressure relief mechanism 3a. If the discharge medium cannot be discharged in time through the first pressure relief mechanism 3a, the discharge medium can flow to the second pressure relief mechanism 3b through the channel gap 5 and be discharged through the second pressure relief mechanism 3b to improve the timeliness of pressure relief of the battery cell 10; if the thermal runaway area of ​​the main body 21 of the electrode assembly 2 is located in the second half zone 14, a large amount of discharge medium will accumulate near the second pressure relief mechanism 3b. If the discharge medium cannot be discharged in time through the second pressure relief mechanism 3b, the discharge medium can flow to the first pressure relief mechanism 3a through the channel gap 5 and be discharged through the first pressure relief mechanism 3a to improve the timeliness of pressure relief of the battery cell 10.

[0151] In some embodiments, the first pressure relief mechanism 3a and the second pressure relief mechanism 3b are symmetrically arranged with respect to the middle section W of the housing 1. This ensures that the pressure relief areas of the first pressure relief mechanism 3a and the second pressure relief mechanism 3b are equal, and the distances from the first pressure relief mechanism 3a and the second pressure relief mechanism 3b to the middle section W of the housing 1 along the length direction Z are equal. Therefore, both the first pressure relief mechanism 3a and the second pressure relief mechanism 3b can provide good pressure relief effects when a battery cell experiences thermal runaway.

[0152] In some embodiments, referring to FIG11 , which is a cross-sectional view of a battery cell 10 according to another embodiment of the present application, the plurality of pressure relief mechanisms 3 further includes a third pressure relief mechanism 3 c disposed on the first wall portion 171 , with a portion of the third pressure relief mechanism 3 c located in the first half 13 and another portion located in the second half 14 .

[0153] In this embodiment, in addition to the first and second pressure relief mechanisms 3a and 3b, the first wall portion 171 also includes a third pressure relief mechanism 3c. The pressure relief mechanism 3 intersects the mid-section W, which divides the pressure relief mechanism 3 into two parts: one located in the first half 13 and the other located in the second half 14.

[0154] In this embodiment, a pressure relief mechanism 3 is also provided in the middle area of ​​the first wall portion 171 , which is beneficial for the discharge of the discharge medium located in the middle area of ​​the housing 1 and can improve the timeliness of the pressure relief of the battery cell 10 .

[0155] In some embodiments, referring to Figures 11 and 12 , Figure 12 is an isometric view of a battery cell 10 (housing 1 is cylindrical) provided in some embodiments of the present application. At least one pressure relief mechanism 3 is provided on the side wall 17 . A portion of the at least one pressure relief mechanism 3 on the side wall 17 is located in the first half 13 , and another portion is located in the second half 14 .

[0156] The pressure relief mechanism 3 , part of which is located in the first half area 13 and the other part of which is located in the second half area 14 , can be one or more. If there are more than one pressure relief mechanism 3 , the multiple pressure relief mechanisms 3 can be arranged at intervals along the circumference of the side wall 17 .

[0157] In this embodiment, not only the first half area 13 and the second half area 14 of the housing 1 are provided with a pressure relief mechanism 3 , but also the middle area of ​​the side wall 17 of the housing 1 is provided with a pressure relief mechanism 3 , which can improve the timeliness of pressure relief of the battery cell 10 .

[0158] In some embodiments, please continue to refer to Figures 11 and 12. The side wall 17 is provided with multiple pressure relief mechanisms 3, and the multiple pressure relief mechanisms 3 include a first pressure relief mechanism 3a, a second pressure relief mechanism 3b and a third pressure relief mechanism 3c. The first pressure relief mechanism 3a is located in the first half area 13, the second pressure relief mechanism 3b is located in the second half area 14, and a part of the third pressure relief mechanism 3c is located in the first half area 13, and the other part is located in the second half area 14.

[0159] There may be one or more first pressure relief mechanisms 3a on the side wall 17. If there are multiple first pressure relief mechanisms 3a on the side wall 17, the multiple first pressure relief mechanisms 3a may be spaced apart along the circumference of the side wall 17, or may be spaced apart along the length direction Z of the shell 1. There may be one or more second pressure relief mechanisms 3b on the side wall 17. If there are multiple second pressure relief mechanisms 3b on the side wall 17, the multiple second pressure relief mechanisms 3b may be spaced apart along the circumference of the side wall 17, or may be spaced apart along the length direction Z of the shell 1. There may be one or more third pressure relief mechanisms 3c on the side wall 17. If there are multiple third pressure relief mechanisms 3c on the side wall 17, the multiple third pressure relief mechanisms 3c may be spaced apart along the circumference of the side wall 17.

[0160] In the embodiment shown in Figure 11 , the side wall 17 is in the shape of a rectangular parallelepiped. In the embodiment shown in Figure 12 , the side wall 17 is in the shape of a cylinder.

[0161] In this embodiment, a first pressure relief mechanism 3a, a second pressure relief mechanism 3b and a third pressure relief mechanism 3c are provided on the side wall 17. The discharge medium in the two end areas of the internal space of the shell 1 can be discharged through the first pressure relief mechanism 3a and the second pressure relief mechanism 3b respectively, and the discharge medium in the middle area can be discharged through the third pressure relief mechanism 3c, thereby improving the timeliness of the pressure relief of the battery cell 10.

[0162] In some embodiments, referring to Figures 10-12 , the housing 1 includes a shell 11 and two end caps 12 . The shell 11 has openings formed at opposite ends along the length direction Z of the shell 1 . The two end caps 12 respectively close the openings at the ends of the shell 11 . The two end caps 12 are respectively a first end wall 15 and a second end wall 16 .

[0163] It can be understood that the shell 11 is a hollow structure with openings formed at two opposite ends, and the shell 11 is the side wall 17 of the outer shell 1 .

[0164] It should be noted that, in this embodiment, both end covers 12 may be provided with a pressure relief mechanism 3, so that both the first half zone 13 and the second half zone 14 are provided with a pressure relief mechanism 3; or one end cover 12 may be provided with a pressure relief mechanism 3, and the shell 11 may be provided with a pressure relief mechanism 3, and the pressure relief mechanism 3 provided on the end cover 12 may be located in the first half zone 13, and the pressure relief mechanism 3 provided on the shell 11 may be located in the second half zone 14, or the pressure relief mechanism 3 provided on the end cover 12 may be located in the second half zone 14, and the pressure relief mechanism 3 provided on the shell 11 may be located in the first half zone 13; or a plurality of pressure relief mechanisms 3 may be provided on the shell 11, and a part of the pressure relief mechanisms 3 on the shell 11 may be located in the first half zone 13, and another part of the pressure relief mechanisms 3 may be located in the second half zone 14.

[0165] In this embodiment, the shell 11 is a hollow structure with openings at both ends. The electrode assembly 2 can be inserted into the shell from any end of the shell 11, which can improve the efficiency of the electrode assembly 2 being inserted into the shell.

[0166] In some embodiments, please refer to Figure 13, which is an exploded view of a battery cell 10 (housing 1 is cylindrical) provided in some embodiments of the present application. Housing 1 includes a shell 11 and an end cap 12. Shell 11 has an opening formed at one end along the length direction Z of housing 1, and end cap 12 closes the opening of shell 11. End cap 12 is a first end wall 15, and the wall of housing 11 opposite end cap 12 along the length direction Z of housing 1 is a second end wall 16.

[0167] It can be understood that the shell 11 is a hollow structure with an opening formed at one end, and the side wall 17 and the second end wall 16 of the outer shell 1 constitute the shell 11 .

[0168] It should be noted that, in this embodiment, the end cover 12 and the wall of the shell 11 opposite to the end cover 12 may be provided with a pressure relief mechanism 3, so that the first half area 13 and the second half area 14 are both provided with a pressure relief mechanism 3; the end cover 12 and the shell 11 may be provided with a pressure relief mechanism 3, or the end cover 12 and the side wall 17 may be provided with a pressure relief mechanism 3, the pressure relief mechanism 3 on the end cover 12 is located in the first half area 13 (not shown in FIG13 ), and the pressure relief mechanism 3 on the side wall 17 is located in the second half area 13 (not shown in FIG13 ). Zone 14; it is also possible that the wall portion opposite to the end cover 12 of the shell 11 and the side wall 17 are both provided with a pressure relief mechanism 3, the pressure relief mechanism 3 on the wall portion opposite to the end cover 12 of the shell 11 is located in the second half zone 14, and the pressure relief mechanism 3 on the side wall 17 is located in the first half zone 13 (not shown in Figure 13); it is also possible that a plurality of pressure relief mechanisms 3 are provided on the side wall 17 of the shell 11, a part of the pressure relief mechanisms 3 on the side wall 17 are located in the first half zone 13, and another part of the pressure relief mechanisms 3 are located in the second half zone 14.

[0169] As an example, in Figure 13, the side wall 17 of the shell 11 is provided with a first pressure relief mechanism 3a, a second pressure relief mechanism 3b and a third pressure relief mechanism 3c, the first pressure relief mechanism 3a is located in the first half area 13, the second pressure relief mechanism 3b is located in the second half area 14, and a part of the third pressure relief mechanism 3c is located in the first half area 13, and the other part is located in the second half area 14.

[0170] In this embodiment, the shell 11 is a hollow structure with an opening at one end. The electrode assembly 2 is accommodated in the shell 11. The opening of the shell 11 is closed by the end cover 12, and the assembly of the battery cell 10 can be completed, which can effectively reduce the difficulty of assembling the battery cell 10.

[0171] In some embodiments, please continue to refer to Figure 5, the shell 1 includes a first wall portion 171, and the first wall portion 171 is provided with a plurality of pressure relief mechanisms 3 arranged at intervals along the length direction Z. The pressure relief mechanisms 3 are provided with notched grooves 175. Along the length direction, the sum of the maximum spans of the notched grooves 175 of the plurality of pressure relief mechanisms 3 is L1, satisfying: 0.2≤L1 / L≤0.6.

[0172] The maximum span of the scored groove 175 along the longitudinal direction Z is the distance between the two most distant locations of the scored groove 175 along the longitudinal direction Z. The maximum spans of the scored grooves 175 along the longitudinal direction Z of all pressure relief mechanisms 3 on the first wall portion 171 may be equal, or the maximum spans of the scored grooves 175 along the longitudinal direction Z of at least two pressure relief mechanisms 3 on the first wall portion 171 may be different. The scored groove 175 may be a groove extending along a closed trajectory, which may be circular, rectangular, or the like; or it may be a groove along a non-closed trajectory, which may be linear, arc-shaped, U-shaped, H-shaped, V-shaped, L-shaped, Y-shaped, or the like. The scored groove 175 may be located on the inner side of the pressure relief mechanism 3 (the side of the pressure relief mechanism 3 facing the interior of the housing 1 along the thickness direction of the first wall portion) or on the outer side of the pressure relief mechanism 3 (the side of the pressure relief mechanism 3 facing away from the interior of the housing 1 along the thickness direction of the first wall portion). It should be noted that, among the multiple pressure relief mechanisms 3 of the first wall portion 171, the notched grooves 175 of some of the pressure relief mechanisms 3 can be arranged on the inner side of the pressure relief mechanism 3, and the notched grooves 175 of another part of the pressure relief mechanisms 3 can be arranged on the outer side of the pressure relief mechanism 3, or the notched grooves 175 of all the pressure relief mechanisms 3 can be arranged on the inner side of the pressure relief mechanism 3, or the notched grooves 175 of all the pressure relief mechanisms 3 can be located on the outer side of the pressure relief mechanism 3.

[0173] In an embodiment where the sidewall 17 of the housing 1 is a hollow rectangular parallelepiped structure, the first wall portion 171 may be any wall portion of the sidewall 17. As an example, in FIG5 , the first wall portion 171 is the wall portion of the sidewall 17 that supports the main body 21 in the direction of gravity. In an embodiment where the sidewall 17 of the housing 1 is a hollow cylindrical structure, the entire sidewall 17 may serve as the first wall portion 171.

[0174] Taking the case where only two pressure relief mechanisms 3 are provided on the first wall portion 171 as an example, the maximum span of the notched groove 175 of one pressure relief mechanism 3 along the length direction Z is L2, and the maximum span of the notched groove 175 of the other pressure relief mechanism 3 along the length direction Z is L3, L1=L2+L3.

[0175] L1 / 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 of values ​​between any two of them.

[0176] In this embodiment, L1 / L ≥ 0.2, which increases the sum of the maximum spans of the notched grooves 175 of the multiple pressure relief mechanisms 3 on the first wall portion 171 along the length direction Z. This increases the total pressure relief area of ​​the multiple pressure relief mechanisms 3 on the first wall portion 171, thereby improving the pressure relief rate of the battery cell 10. L1 / L ≤ 0.6 prevents the sum of the maximum spans of the notched grooves 175 of the multiple pressure relief mechanisms 3 on the first wall portion 171 along the length direction Z from being too large, thereby improving the strength of the first wall portion 171.

[0177] In some embodiments, please refer to Figures 14 and 15. Figure 14 is an isometric view of a battery cell 10 (housing 1 is cylindrical) provided in other embodiments of the present application; Figure 15 is a cross-sectional view of a battery cell 10 (housing 1 is cylindrical) provided in some embodiments of the present application. The battery cell 10 also includes an electrode assembly 2, which is housed within the housing 1. The electrode assembly 2 includes a main body 21 and a tab 22. The main body 21 is provided with a tab 22 at at least one end along the longitudinal direction Z of the housing 1. A portion of the main body 21 is located in the first half 13, and another portion is located in the second half 14. The main body 21 is provided with a central hole 211, which extends through the main body 21 along the longitudinal direction Z of the housing 1. The central hole 211 is used to connect the interior space of the first half 13 with the interior space of the second half 14.

[0178] In this embodiment, the housing 1 can be cylindrical, prismatic, or other shapes. The pressure relief mechanism 3 located in the first half 13 can be disposed on the first end wall 15 or the side wall 17; the pressure relief mechanism 3 located in the second half 14 can be disposed on the second end wall 16 or the side wall 17. As an example, as shown in FIG14 , the side wall 17 is provided with two pressure relief mechanisms: a first pressure relief mechanism 3a and a second pressure relief mechanism 3b. The first pressure relief mechanism 3a is disposed in the first half 13, and the second pressure relief mechanism 3b is disposed in the second half 14.

[0179] Along the length direction Z of the shell 1, one end of the center hole 211 extends to one end of the main body 21, and one end of the center hole 211 extends to the other end of the main body 21 to penetrate the main body 21. The center hole 211 can be a circular hole, a polygonal hole, etc. The cross-section of the hole wall of the circular hole is circular, and the cross-section of the hole wall of the polygonal hole is polygonal. The polygon can be a triangle, a quadrilateral, a pentagon, a hexagon, etc. The cross-section referred to here is perpendicular to the length direction Z of the shell 1. The tab 22 at the end of the main body 21 does not block the center hole 211. The electrode assembly 2 can be a wound structure formed by winding a positive electrode sheet, a separator, and a negative electrode sheet. After the electrode assembly 2 is formed by winding, a center hole 211 is formed corresponding to the center position of the electrode assembly 2. The electrode assembly 2 can also be a laminated structure formed by stacking a positive electrode sheet, a separator, and a negative electrode sheet, and the center hole 211 can be machined at the center position of the electrode assembly 2.

[0180] As an example, as shown in FIG15 , along the length direction Z of the housing 1 , tabs 22 are provided at both ends of the main body 21. Electrode terminals 4 are provided on both the first end wall 15 and the second end wall 16. The tab 22 at one end of the main body 21 is electrically connected to the electrode terminal 4 on the first end wall 15, while the tab 22 at the other end of the main body 21 is electrically connected to the electrode terminal 4 on the second end wall 16. The electrode terminals 4 on the first end wall 15 and the electrode terminals 4 on the second end wall 16 have opposite polarities. Optionally, two electrode terminals 4 are provided on the first end wall 15, connected by a connecting block 6 located on the side of the first end wall 15 facing away from the main body 21. Two electrode terminals 4 are provided on the second end wall 16, connected by another connecting block 6 located on the side of the second end wall 16 facing away from the main body 21. The connecting block 6 is a conductor and can be made of copper, iron, aluminum, an aluminum alloy, steel, or the like.

[0181] In this embodiment, the center hole 211 of the main body 21 can serve as a flow channel for the discharge medium inside the shell 1. The discharge medium at one end of the main body 21 can be discharged through the pressure relief mechanism 3 of the first half area 13, and can also flow to the other end of the main body 21 through the center hole 211 and be discharged through the pressure relief mechanism 3 of the second half area 14, thereby improving the timeliness of pressure relief of the battery cell 10.

[0182] In some embodiments, referring to FIG. 15 , the battery cell 10 further includes a support member 7 . The support member 7 is disposed in the central hole 211 and supported on the wall surface of the central hole 211 .

[0183] The support member 7 contacts the wall surface of the center hole 211 and provides support for the wall surface. The support member 7 can be made of metal, such as copper, iron, aluminum, aluminum alloy, steel, etc.; the support member 7 can also be made of non-metallic materials, such as plastic or rubber. A channel can be formed inside the support member 7 to keep the center hole 211 unobstructed. The support member 7 can be a hollow cylindrical member or a winding member wound within the center hole 211. The support member 7 can be fixed to the wall surface to ensure that the support member 7 contacts the wall surface of the center hole 211.

[0184] In this embodiment, the provision of the support member 7 can reduce the risk of collapse of the center hole 211. On the one hand, it can keep the center hole 211 unobstructed, so that the discharge medium at one end of the main body 21 can flow through the center hole 211 to the other end of the main body 21. On the other hand, it can reduce the risk of lithium deposition caused by the collapse of the center hole 211.

[0185] In some embodiments, the support member 7 is an adhesive layer adhered to the wall surface of the central hole 211 .

[0186] The adhesive layer can be a solid layer formed by solidifying the glue applied to the hole wall, or it can be an adhesive tape, adhesive strip, etc. adhered to the hole wall.

[0187] In this embodiment, the support member 7 is not easily separated from the wall surface of the central hole 211 , and the support member 7 can provide better support and reinforcement for the central hole 211 .

[0188] In some embodiments, the electrode assembly 2 includes a positive electrode sheet, a negative electrode sheet and an isolating member. The isolating member is arranged between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the isolating member and the negative electrode sheet are wound to form a winding structure. The isolating member defines a center hole 211, and the support member 7 is connected to the isolating member.

[0189] It can be understood that the wall surface of the central hole 211 is a part of the surface of the isolation element.

[0190] The support member 7 and the spacer can be connected in a variety of ways, such as hot melt connection, bonding, etc. Taking the spacer as an adhesive layer as an example, the support member 7 and the spacer are bonded. As an example, the support member 7 is a winding member wound in the center hole 211.

[0191] In this embodiment, before the electrode assembly 2 is formed, the support member 7 can be connected to the isolation member first. After the positive electrode sheet, isolation member and negative electrode sheet are wound to form the electrode assembly 2, the support member 7 is located in the center hole 211 and supports the hole wall of the center hole 211. In this way, the difficulty of arranging the support member 7 in the center hole 211 can be reduced.

[0192] In other embodiments, the central hole 211 may be defined by the positive electrode sheet or the negative electrode sheet, and the support member 7 may be connected to the positive electrode sheet or the negative electrode sheet.

[0193] In some embodiments, the diameter of the center hole 211 is D, which satisfies: 3 mm ≤ D ≤ 8 mm.

[0194] It should be noted that, in the embodiment where the center hole 211 is a circular hole, the diameter of the cross section of the hole wall of the center hole 211 is the diameter of the center hole 211; when the center hole 211 is a polygonal hole, the diameter of the circumscribed circle of the cross section of the hole wall of the center hole 211 is the diameter of the center hole 211.

[0195] D can be any point value among 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, or a range value between any two of them.

[0196] In this embodiment, D ≥ 3 mm, so that the center hole 211 has a larger aperture, so that the discharge medium inside the shell 1 at one end of the main body 21 can flow more quickly through the center hole 211 to the other end of the main body 21; D ≤ 8 mm, so that the aperture of the center hole 211 is not too large, reducing the risk of collapse of the center hole 211.

[0197] In some embodiments, please continue to refer to Figure 15. The battery cell 10 also includes an electrode terminal 4 and a current collecting component 8. The electrode terminal 4 is arranged on the outer shell 1, and the current collecting component 8 is arranged on the side of the main body 21 facing the electrode terminal 4. The current collecting component 8 connects the electrode terminal 4 and the tab 22. The current collecting component 8 is provided with a first through hole 81, and the first through hole 81 is connected to the center hole 211.

[0198] The current collecting member 8 can be a metal conductor, such as copper, iron, aluminum, steel, or an aluminum alloy. The current collecting member 8 can be a current collecting plate disposed between the electrode terminal 4 and the tab 22, or a transition piece folded between the electrode terminal 4 and the tab 22. The first through hole 81 can be a circular hole, a polygonal hole, or the like.

[0199] As an example, in the embodiment shown in Figure 15, along the length direction Z of the outer shell 1, the pole ear 22 at one end of the main body 21 is connected to the electrode terminal 4 on the first end wall 15 through a current collecting component 8, and the pole ear 22 at the other end of the main body 21 is connected to the electrode terminal 4 on the second end wall 16 through another current collecting component 8, so as to realize the electrical connection between the electrode terminal 4 on the first end wall 15 and the second end wall 16 and the electrode assembly 2.

[0200] In this embodiment, the current collecting member 8 is provided with a first through hole 81 , so that the current collecting member 8 is unlikely to block the central hole 211 , and the discharge medium entering the central hole 211 can smoothly flow to the pressure relief mechanism 3 .

[0201] In some embodiments, please continue to refer to FIG. 15 , along the length direction Z of the housing 1 , the projection of the hole wall of the first through hole 81 is at least partially located within the central hole 211 .

[0202] As an example, the first through hole 81 and the center hole 211 are both circular holes, and the first through hole 81 and the center hole 211 are coaxially arranged. The diameter of the first through hole 81 is smaller than the diameter of the center hole 211, so that the projection of the hole wall surface of the first through hole 81 along the length direction Z of the shell 1 is entirely located within the center hole 211.

[0203] In this embodiment, the projection of the hole wall of the first through hole 81 is at least partially located in the center hole 211, reducing the obstruction of the collecting component 8 on the discharge medium in the center hole 211, so that the discharge medium in the center hole 211 can quickly flow through the first through hole 81 to the pressure relief mechanism 3.

[0204] In some embodiments, referring to Figures 16-18 , Figure 16 is an isometric view of a housing 1 provided in some embodiments of the present application; Figure 17 is a cross-sectional view of the housing 1 shown in Figure 16 ; and Figure 18 is a partial enlarged view of the housing 1 at point B shown in Figure 17 . Pressure relief mechanism 3 is provided with a notched groove 175 . A weakened area 176 is formed in the region where notched groove 175 is provided. Weakened area 176 is configured to rupture to release pressure within battery cell 10 .

[0205] The weak area 176 is a portion of the pressure relief mechanism 3 that is weaker than other areas. After the notch 175 is formed on the pressure relief mechanism 3, the remaining portion of the pressure relief mechanism 3 corresponding to the notch 175 is the weak area 176, which can be the bottom wall of the notch 175.

[0206] The scoring groove 175 can be formed in various ways, such as stamping, milling, laser etching, etc. The extending direction of the scoring groove 175 is the same as the extending direction of the weak area 176 .

[0207] In this embodiment, a weak area 176 is formed in the corresponding area of ​​the pressure relief mechanism 3 by providing a notched groove 175. The method for forming the weak area 176 is simple. The weak area 176 is a weaker area in the pressure relief mechanism 3. The weak area 176 is more easily destroyed in the event of thermal runaway of the battery cell 10, thereby releasing the pressure inside the battery cell 10.

[0208] In some embodiments, the pressure relief mechanism 3 includes a pressure relief area 31 , and the weakened area 176 is provided along an edge of the pressure relief area 31 . The pressure relief area 31 is configured to be opened when the weakened area 176 ruptures.

[0209] The pressure relief area 31 is the portion of the pressure relief mechanism 3 that can be opened after being split along the weak area 176. During pressure relief, the pressure relief area 31 can be opened in a flipping or detaching manner.

[0210] In this embodiment, the notched groove 175 may be a groove extending along a closed track; the notched groove 175 may also be a groove extending along a non-closed track, and the non-closed track may be arc-shaped, U-shaped, H-shaped, V-shaped, L-shaped, etc.

[0211] In this embodiment, the weak area 176 defines the pressure relief area 31 . During pressure relief, the pressure relief area 31 can be opened with the weak area 176 as the boundary, thereby increasing the pressure relief area of ​​the pressure relief mechanism 3 .

[0212] In some embodiments, the score groove 175 is a groove extending along a closed trajectory.

[0213] The notched groove 175 is an annular groove, which may be a rectangular annular groove, a circular annular groove, etc. The rectangular annular groove is a groove extending along a rectangular track, and the circular annular groove is a groove extending along a circular track.

[0214] During the pressure relief process, the pressure relief region 31 of the pressure relief mechanism 3 can be separated from the housing 1 after the pressure relief mechanism 3 is split along the notched groove 175 , thereby increasing the pressure relief area and improving the pressure relief rate of the battery cell 10 .

[0215] In some embodiments, please continue to refer to Figures 16 to 18, the pressure relief mechanism 3 is integrally formed with the corresponding wall portion of the housing 1.

[0216] In the embodiment where the pressure relief mechanism 3 is provided on the first end wall 15, the pressure relief mechanism 3 on the first end wall 15 is integrally formed with the first end wall 15. In the embodiment where the pressure relief mechanism 3 is provided on the second end wall 16, the pressure relief mechanism 3 on the second end wall 16 is integrally formed with the second end wall 16. In the embodiment where the pressure relief mechanism 3 is provided on the side wall 17, the pressure relief mechanism 3 on the side wall 17 is integrally formed with the corresponding wall portion of the side wall 17. If the side wall 17 is cylindrical, the pressure relief mechanism 3 is integrally formed with the side wall 17. If the side wall 17 is rectangular, the wall portion of the side wall 17 where the pressure relief mechanism 3 is provided is integrally formed with the pressure relief mechanism 3.

[0217] As an example, as shown in Figures 16-18, the side wall 17 includes a first wall portion 171, a second wall portion 172, a third wall portion 173, and a fourth wall portion 174. The first wall portion 171 and the second wall portion 172 are arranged relative to each other along a first direction X, and the third wall portion 173 and the fourth wall portion 174 are arranged relative to each other along a second direction Y. The first wall portion 171, the third wall portion 173, the second wall portion 172, and the fourth wall portion 174 are connected end to end, and the longitudinal direction Z, the first direction X, and the second direction Y of the housing 1 are perpendicular to each other. The third wall portion 173 and the fourth wall portion 174 can be the wall portion with the largest outer surface area in the housing 1. The first wall portion 171 can be used to support the main body portion 21 (not shown in Figure 17) along the direction of gravity, and the first direction X is parallel to the direction of gravity. The first wall portion 171 is provided with a pressure relief mechanism 3, which is integrally formed with the first wall portion 171.

[0218] In an embodiment in which the pressure relief mechanism 3 is provided with a notched groove 175, the weak area 176 and the pressure relief area 31 may constitute the pressure relief mechanism, and the weak area 176, the pressure relief area 31 and the corresponding wall portion of the outer shell 1 may be integrally formed, thereby enabling the pressure relief mechanism 3 and the corresponding wall portion of the outer shell 1 to be integrally formed.

[0219] In this embodiment, the pressure relief mechanism 3 is integrally formed with the corresponding wall portion of the housing 1 , which increases the reliability of the pressure relief mechanism 3 and eliminates the connection process between the pressure relief mechanism 3 and the housing 1 , thereby reducing the production cost of the battery cell 10 .

[0220] In some embodiments, please refer to FIG19 , which is a partial enlarged view of the housing 1 provided in some other embodiments of the present application. The pressure relief mechanism 3 is provided separately from the housing 1 , and the housing 1 is provided with a pressure relief hole 177 . The pressure relief mechanism 3 is installed on the housing 1 and covers the pressure relief hole 177 .

[0221] The pressure relief mechanism 3 and the housing 1 are two separate components that are molded separately and then assembled together. The pressure relief mechanism 3 can be a component such as an explosion-proof disk, explosion-proof valve, or safety valve. Taking the first wall portion 171 of the housing as an example, the pressure relief mechanism 3 can be mounted to the first wall portion 171 by bonding, welding, or other methods. When the battery cell 10 experiences thermal runaway, the pressure relief mechanism 3 opens at least a portion of the pressure relief holes 177, allowing the exhaust medium within the battery cell 10 to be discharged through the pressure relief holes 177, thereby relieving the pressure within the battery cell 10.

[0222] As an example, as shown in Figure 19, the pressure relief mechanism 3 is a bursting disc mounted on the first wall portion 171. The bursting disc is a sheet with at least a portion of its strength being less than that of the first wall portion 171. The bursting disc covers the pressure relief holes 177 and is welded to the first wall portion 171. When a battery cell 10 experiences thermal runaway, the bursting disc is at least partially destroyed, thereby opening at least a portion of the pressure relief holes 177 to release pressure within the battery cell 10. The pressure relief mechanism 3 can be provided with a notched groove 175 to form a corresponding weak area 176.

[0223] In this embodiment, the pressure relief mechanism 3 is a component independent of the housing 1 . The pressure relief mechanism 3 and the housing 1 can be produced and assembled separately, which reduces production difficulty and increases efficiency.

[0224] In some embodiments, referring to FIG. 3 to FIG. 11 , the housing 1 is in the shape of a cuboid.

[0225] In some embodiments, referring to FIG. 12 to FIG. 15 , the housing 1 is cylindrical, and the axial direction of the housing 1 is parallel to the length direction Z.

[0226] In some embodiments, L ≥ 160 mm.

[0227] 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.

[0228] When the length of the shell 1 is greater than or equal to 160 mm, it is more difficult for the battery cell 10 to achieve timely pressure relief during thermal runaway. However, in this embodiment, the first half area 13 and the second half area 14 of the shell 1 are both provided with a pressure relief mechanism 3, which can alleviate the situation where the battery cell 10 is not relieved of pressure in a timely manner.

[0229] An embodiment of the present application provides a battery 100 , comprising the battery cell 10 provided in any one of the above embodiments.

[0230] 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.

[0231] In addition, as shown in Figures 14 and 15, an embodiment of the present application further provides a battery cell 10, comprising a housing 1, an electrode assembly 2, a pressure relief mechanism 3, and a current collecting member 8. The housing 1 is cylindrical and includes a first half 13 and a second half 14. Along the length direction Z of the housing 1, the portion from the mid-section W of the housing 1 to one end of the housing 1 constitutes the first half 13, and the portion from the mid-section W of the housing 1 to the other end of the housing 1 constitutes the second half 14. The length of the housing 1 is L, where L is ≥ 80 mm. The housing 1 includes a shell 11 and two end caps 12. Along the length direction Z of the housing 1, openings are formed at opposite ends of the housing 11. The two end caps 12 respectively seal the two openings of the housing 11. The housing 11 is provided with a first pressure relief mechanism 3a and a second pressure relief mechanism 3b. The first pressure relief mechanism 3a is located in the first half 13, and the second pressure relief mechanism 3b is located in the second half 14. 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 length direction Z of the housing 1. A portion of the main body 21 is located in the first half 13, and the other portion is located in the second half 14. Both end caps 12 are provided with electrode terminals 4. The tab 22 at one end of the main body 21 is electrically connected to the electrode terminal 4 on one end cap 12 via a current collecting member 8, and the tab 22 at the other end of the main body 21 is electrically connected to the electrode terminal 4 on the other end cap 12 via another current collecting member 8.

[0232] The electrode assembly 2 comprises a positive electrode sheet, a negative electrode sheet, and a separator. The positive, separator, and negative electrode sheets are wound together to form a wound structure. The main body 21 has a central hole 211 extending through the main body 21 along the length direction Z of the outer shell 1. The separator defines the central hole 211, which connects the interior space of the first half section 13 with the interior space of the second half section 14. A support member 7 is disposed within the central hole 211 and is supported by the wall of the central hole 211. The support member 7 is a layer of adhesive adhered to the wall of the central hole 211. The diameter of the central hole 211 is D, with a range of 3 mm ≤ D ≤ 8 mm. Both current collecting members 8 are provided with a first through hole 81, which communicates with the central hole 211. The first through hole 81 and the central hole 211 are both circular holes and coaxially arranged. The diameter of the first through hole 81 is smaller than that of the central hole 211.

[0233] 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.

[0234] 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 shell, comprising a first half region and a second half region, wherein along the length direction of the shell, a portion from the middle section of the shell to one end of the shell is the first half region, and a portion from the middle section of the shell to the other end of the shell is the second half region, the length of the shell is L, L ≥ 80 mm, and the middle section is perpendicular to the length direction; an electrode assembly, contained in the housing, the electrode assembly comprising a main body and a tab, the tab being disposed at at least one end of the main body along the length direction, a portion of the main body being located in the first half region, and another portion of the main body being located in the second half region; Wherein, the first half zone and the second half zone are each provided with at least one pressure relief mechanism, and the main body is provided with a central hole, which penetrates the main body along the length direction, and is used to connect the internal space of the first half zone with the internal space of the second half zone.

2. The battery cell according to claim 1, wherein: The housing comprises a first end wall, a second end wall and a side wall, the first end wall is located in the first half area, the second end wall is located in the second half area, the first end wall and the second end wall are arranged opposite to each other along the length direction, and the side wall is arranged around the first end wall and the second end wall; The first end wall and the second end wall are both provided with at least one pressure relief mechanism; and / or, the portion of the side wall located in the first half zone and the portion of the side wall located in the second half zone are both provided with at least one pressure relief mechanism; and / or, the portion of the side wall located in the first half zone and the second end wall are both provided with at least one pressure relief mechanism; and / or, the portion of the side wall located in the second half zone and the first end wall are both provided with at least one pressure relief mechanism.

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

4. The battery cell according to claim 3, wherein: in, The first wall portion is provided with at least one pressure relief mechanism.

5. The battery cell according to claim 4, wherein: The first wall portion is provided with a plurality of the pressure relief mechanisms, including a first pressure relief mechanism and a second pressure relief mechanism provided on the first wall portion, the first pressure relief mechanism is located in the first half area, and the second pressure relief mechanism is located in the second half area.

6. The battery cell according to claim 5, wherein: The first pressure relief mechanism and the second pressure relief mechanism are symmetrically arranged with respect to a middle section of the housing.

7. The battery cell according to claim 5 or 6, wherein: The plurality of pressure relief mechanisms further include a third pressure relief mechanism disposed on the first wall portion, a portion of the third pressure relief mechanism being located in the first half area, and another portion of the third pressure relief mechanism being located in the second half area.

8. The battery cell according to any one of claims 2 to 7, wherein: The side wall is provided with at least one pressure relief mechanism, and a portion of the at least one pressure relief mechanism on the side wall is located in the first half area, and another portion is located in the second half area.

9. The battery cell according to claim 8, wherein: The side wall is provided with a plurality of pressure relief mechanisms, including a first pressure relief mechanism, a second pressure relief mechanism and a third pressure relief mechanism. The first pressure relief mechanism is located in the first half area, the second pressure relief mechanism is located in the second half area, a part of the third pressure relief mechanism is located in the first half area, and the other part is located in the second half area.

10. The battery cell according to any one of claims 2 to 9, wherein: The housing comprises: The shell has openings formed at two opposite ends along the length direction; Two end covers, the two end covers respectively closing the openings at both ends of the shell; Wherein, the two end covers are respectively the first end wall and the second end wall.

11. The battery cell according to any one of claims 2 to 9, wherein: The housing comprises: A shell having an opening formed at one end along the length direction; an end cap for closing the opening; The end cover is the first end wall, and along the length direction, the wall portion of the shell body opposite to the end cover is the second end wall.

12. The battery cell according to any one of claims 1 to 11, wherein: The shell includes a first wall portion, the first wall portion is provided with a plurality of pressure relief mechanisms arranged at intervals along the length direction, the pressure relief mechanisms are provided with notched grooves, and along the length direction, the sum of the maximum spans of the notched grooves of the plurality of pressure relief mechanisms is L1, satisfying: 0.2≤L1 / L≤0.

6.

13. The battery cell according to any one of claims 1 to 11, wherein: The battery cell further includes a support member, which is disposed in the central hole and supported on a hole wall surface of the central hole.

14. The battery cell according to claim 13, wherein: The support member is a glue layer adhered to the hole wall surface of the central hole.

15. The battery cell according to claim 13 or 14, wherein: The electrode assembly includes a positive electrode sheet, a negative electrode sheet and a separator, wherein the separator is disposed between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet, the separator and the negative electrode sheet are wound to form a winding structure, the separator defines the center hole, and the support member is connected to the separator.

16. The battery cell according to any one of claims 1 to 15, wherein: The diameter of the center hole is D, which satisfies: 3mm≤D≤8mm.

17. The battery cell according to any one of claims 1 to 15, wherein: The battery cell further includes an electrode terminal and a current collecting member, wherein the electrode terminal is disposed on the shell, the current collecting member is disposed on a side of the main body facing the electrode terminal, the current collecting member connects the electrode terminal and the electrode tab, and the current collecting member is provided with a first through hole, which is connected to the central hole.

18. The battery cell according to claim 17, wherein: Along the length direction, a projection of a hole wall surface of the first through hole is at least partially located within the central hole.

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

20. The battery cell according to any one of claims 1 to 18, wherein: The pressure relief mechanism is separately arranged from the shell, the shell is provided with a pressure relief hole, and the pressure relief mechanism is installed on the shell and covers the pressure relief hole.

21. The battery cell according to any one of claims 1 to 20, wherein: The shell is in the shape of a cuboid.

22. The battery cell according to any one of claims 1, 2 and 8-20, wherein: The shell is cylindrical, and the axial direction of the shell is parallel to the length direction.

23. The battery cell according to any one of claims 1 to 22, wherein: L≥160mm.

24. A battery comprising the battery cell according to any one of claims 1 to 23.

25. An electrical device, comprising the battery cell according to any one of claims 1 to 23, wherein the battery cell is used to provide electrical energy to the electrical device.

Images