Battery monomer, battery and electric equipment

Abstract

The embodiment of the invention provides a battery monomer, a battery and electric equipment. The battery cell includes a housing and an electrode assembly. The shell comprises an end wall and a side wall, the end wall is arranged at one end, in the first direction, of the side wall, and the side wall surrounds the end wall. The electrode assembly is contained in the shell, and a first flow guide channel is formed between a tab at one end, facing the end wall, of the electrode assembly and the side wall. The end wall comprises a wall body and an abutting part, the wall body is provided with a pressure relief mechanism, and the abutting part is arranged on the outer edge of the wall body in a surrounding mode. In the first direction, the abutting portion protrudes from the wall body in the direction close to the electrode assembly and directly or indirectly abuts against the tab. The abutting part and the wall body jointly define a flow guide space, the abutting part is provided with a second flow guide channel, and the second flow guide channel communicates with the flow guide space and the first flow guide channel. When the single battery is in thermal runaway, emissions generated by the electrode assembly can quickly flow to the flow guide space through the second flow guide channel on the abutting part, so that the reliability of the single battery is effectively improved.

Description

Battery cells, batteries and electrical equipment

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery, and an electrical device.

[0002] In recent years, new energy vehicles have experienced rapid development. In the field of electric vehicles, power batteries, as the power source, play an irreplaceable and crucial role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also increasing. As the demand for batteries grows, higher requirements are placed on the reliability of individual battery cells. Therefore, how to improve the reliability of individual battery cells is an urgent problem to be solved in battery technology.

[0003] Summary of the Invention

[0004] This application provides a battery cell, a battery, and an electrical device, which can effectively improve the reliability of the battery cell.

[0005] In a first aspect, embodiments of this application provide a battery cell, including a housing and an electrode assembly; the housing includes an end wall and a side wall, the end wall being disposed at one end of the side wall along a first direction, and the side wall surrounding the end wall; the electrode assembly is housed within the housing, and the end of the electrode assembly facing the end wall has a tab, and a first flow channel is formed between the tab and the side wall; wherein, the end wall includes a wall body and an abutment portion, the wall body being provided with a pressure relief mechanism, and the abutment portion being disposed around the outer edge of the wall body; along the first direction, the abutment portion protrudes from the wall body in a direction close to the electrode assembly, and directly or indirectly abuts against the tab; the abutment portion and the wall body together define a flow space, and the abutment portion is provided with a second flow channel, the second flow channel connecting the flow space and the first flow channel.

[0006] In the above technical solution, the abutment portion of the end wall directly or indirectly abuts against the electrode tab. The abutment portion can restrict the electrode assembly and reduce the risk of the electrode assembly moving along the first direction within the casing. Since the abutment portion is provided with a second flow channel, which connects the flow space and the first flow channel, when a battery cell experiences thermal runaway, the emissions generated by the electrode assembly flow into the first flow channel. The emissions can then quickly flow into the flow space through the second flow channel on the abutment portion, causing the air pressure in the flow space to rise rapidly. This quickly reaches the burst pressure of the pressure relief mechanism, shortening the time from battery cell thermal runaway to the start of pressure relief by the pressure relief mechanism. This allows the pressure relief mechanism to be activated promptly, reducing the risk of battery cell explosion and fire, and effectively improving the reliability of the battery cell.

[0007] In some embodiments, the abutment portion is provided with a plurality of second flow channels, which are spaced apart circumferentially along the abutment portion. This allows the emissions in the first flow channel to enter the flow space through the plurality of second flow channels at different locations, increasing the rate at which the emissions in the first flow channel enter the flow space and further shortening the time from the thermal runaway of the battery cell to the start of pressure relief by the pressure relief mechanism.

[0008] In some embodiments, along the first direction, the abutment portion has an abutment surface, which is the surface of the abutment portion closest to the electrode assembly, and the second flow channel is a notch or groove that penetrates the abutment portion radially and extends to the abutment surface along the first direction. This reduces the molding difficulty of the second flow channel and facilitates increasing the size of the second flow channel along the first direction, thereby increasing the rate at which the discharge material in the first flow channel enters the flow space through the second flow channel.

[0009] In some embodiments, the abutment includes multiple protrusions that directly or indirectly abut against the tab. A second flow channel is formed between two adjacent protrusions along the circumferential direction of the abutment. By forming a second flow channel between two adjacent protrusions, the discharge material in the first flow channel can enter the flow space through multiple second flow channels at different locations, increasing the rate at which the discharge material enters the flow space from the first flow channel. Furthermore, the second flow channel in this structure is a notch or groove formed on the abutment, which reduces the molding difficulty of the second flow channel and facilitates increasing the size of the second flow channel along the first direction.

[0010] In some embodiments, the protrusion has an abutment surface for directly or indirectly abutting against the tab to achieve electrical connection between the end wall and the electrode assembly; the height of the protrusion is H along the first direction; the width of the abutment surface is W along the radial direction of the abutment; 0.1W≤H≤0.5W. By directly or indirectly abutting against the tab with the abutment surface, electrical connection between the end wall and the electrode assembly can be achieved. To achieve stable current flow between the end wall and the electrode assembly, the abutment surface generally has a certain width. Therefore, controlling the height of the protrusion within the range of 0.1W to 0.5W ensures that the dimensions of the second flow channel along the first direction meet the flow requirements, allowing the discharge in the first flow channel to quickly enter the flow space through the second flow channel, while also reducing the impact of excessive protrusion height on the volumetric energy density of the battery cell.

[0011] In some embodiments, the height of the protrusion along the first direction is H, where 5mm ≥ H ≥ 0.5mm. H ≥ 0.5mm ensures that the dimension of the second flow channel along the first direction is greater than or equal to 0.5mm, meeting the flow requirements and allowing emissions from the first flow channel to quickly enter the flow space. H ≤ 5mm prevents the protrusion from being too large, reducing the space occupied by the protrusion within the casing along the first direction and improving the volumetric energy density of the battery cell. This balances the flow requirements of the second flow channel with the volumetric energy density requirements of the battery cell.

[0012] In some embodiments, the protrusion has a first end and a second end opposite each other along the circumference of the abutment portion; the projection of the outer edge of the end wall along a first direction forms a first circle, and when viewed along the first direction, the line connecting the first end and the center of the first circle is the first connecting line, and the line connecting the second end and the center of the first circle is the second connecting line, the angle between the first connecting line and the second connecting line is α, 15°≤α≤60°. By controlling α between 15° and 60°, more protrusions can be provided along the circumference of the abutment portion to form more second guide channels, allowing the discharge in the first guide channel to enter the guide space from more positions.

[0013] In some embodiments, a plurality of protrusions are evenly arranged along the circumference of the abutment portion. This allows the plurality of second flow channels on the abutment portion to be evenly arranged along the circumference of the abutment portion, enabling the discharge in the second flow channels to enter the flow space more evenly from the plurality of flow channels, further increasing the rate at which the discharge in the first flow channel enters the flow space.

[0014] In some embodiments, a flow guiding gap is formed between the sidewall and the protrusion along the radial direction of the abutment portion; the flow guiding gap connects two adjacent second flow guiding channels. The flow guiding gap between the sidewall and the protrusion allows the two adjacent second flow guiding channels to connect, so that when the emissions in the first flow guiding channel flow towards one of the second flow guiding channels, the emissions can flow through the flow guiding gap to the other adjacent second flow guiding channel, allowing the emissions in the first flow guiding channel to enter the flow guiding space more quickly.

[0015] In some embodiments, the abutment portion further includes a body portion, which is disposed around the outer edge of the wall body and protrudes from the wall body in a direction close to the electrode assembly. Along a first direction, the body portion has a first surface facing the electrode assembly, and the protrusion is disposed on the first surface. The body portion serves to connect the wall body and the protrusion. The fact that the body portion is disposed around the wall body and protrudes from the wall body in a direction close to the electrode assembly effectively improves the deformation resistance of the end wall.

[0016] In some embodiments, along the first direction, the wall body has a second surface, which is the surface of the wall body closest to the electrode assembly, and the first surface is closer to the electrode assembly than the second surface. This increases the distance between the second surface and the electrode assembly, reduces the impact of the electrode assembly on the pressure relief mechanism on the wall body, and effectively increases the size of the flow guiding space along the first direction.

[0017] In some embodiments, the abutment portion is provided with a first groove; along a first direction, the body portion has a third surface disposed opposite to the first surface, the first surface being closer to the electrode assembly than the third surface, and the first groove is recessed from the third surface toward the electrode assembly to form a protrusion protruding from the first surface on the side of the body portion facing the electrode assembly. By forming the protrusion corresponding to the first groove on the abutment portion, the molding difficulty of the protrusion portion can be effectively reduced, and the weight of the end wall can be effectively reduced.

[0018] In some embodiments, the first groove is a multi-level groove, and along the first direction, the first-level groove closer to the electrode assembly in two adjacent grooves is disposed on the bottom surface of the first-level groove farther from the electrode assembly. By setting the first groove as a multi-level groove, the forming force on the end wall during the forming of each level groove is lower, reducing the risk of end wall damage due to excessive forming force during the forming of the first groove.

[0019] In some embodiments, the protrusion includes a first portion and a second portion, and the multi-level groove includes a first-level groove and a second-level groove; the first-level groove is recessed from a third surface toward the electrode assembly to form a first portion protruding from the first surface on the side of the body portion facing the electrode assembly, and the first portion has a fourth surface facing the electrode assembly along a first direction; the second-level groove is recessed from the bottom of the first-level groove toward the electrode assembly to form a second portion protruding from the fourth surface on the side of the first portion facing the electrode assembly. By providing a first-level groove on the body portion, the first portion of the protrusion can be formed accordingly, and by providing a second-level groove on the first portion, the second portion of the protrusion can be formed accordingly, thereby reducing the molding difficulty of the protrusion.

[0020] In some embodiments, along the radial direction of the abutment portion, the first portion has a first side surface facing the inner circumferential surface of the sidewall, and the second portion has a second side surface facing the inner circumferential surface of the sidewall. The first side surface is closer to the inner circumferential surface of the sidewall than the second side surface. A flow guiding gap is formed between the second side surface and the inner circumferential surface of the sidewall, and the flow guiding gap connects two adjacent second flow guiding channels. The flow guiding gap between the second side surface and the inner circumferential surface of the sidewall can connect two adjacent second flow guiding channels. When the discharge in the first flow guiding channel flows concentratedly to a certain second flow guiding channel, the discharge can flow through the flow guiding gap to the other adjacent second flow guiding channel, so that the discharge in the first flow guiding channel can enter the flow guiding space more quickly.

[0021] In some embodiments, a second groove is provided on the side of the end wall opposite to the electrode assembly, corresponding to the position of the body portion, and the third surface is the bottom surface of the second groove. By providing a second groove on the end wall to correspondingly form the body portion, the molding difficulty of the body portion can be effectively reduced.

[0022] In some embodiments, the end wall and the side wall are separately provided, and at least a portion of the main body is accommodated within the side wall and forms a positioning fit with the side wall. By forming a positioning fit between the main body and the side wall, the assembly difficulty of the end wall and the side wall can be effectively improved.

[0023] In some embodiments, the end wall further includes an edge portion surrounding the outer edge of the body portion, and the edge portion abutting against one end of the side wall in the direction of the end wall toward the electrode assembly. The abutting of the edge portion against the side wall can limit the end wall, restricting the movement of the end wall in the direction close to the electrode assembly.

[0024] In some embodiments, the wall body and the abutment are integrally formed. This effectively improves the connection strength between the abutment and the wall body.

[0025] In some embodiments, along the first direction, the wall body has a fifth surface, which is the surface of the end wall furthest from the electrode assembly. The pressure relief mechanism is closer to the electrode assembly than the fifth surface. This increases the distance between the pressure relief mechanism and the external component when the fifth surface contacts the external component, reducing the impact of the external component on the pressure relief mechanism and reducing the risk of premature activation of the pressure relief mechanism due to the impact force of the external component.

[0026] In some embodiments, the wall body is provided with a third groove, which is recessed from the fifth surface toward the electrode assembly. A pressure relief groove is provided on the bottom wall of the third groove to form a pressure relief mechanism at a position corresponding to the pressure relief groove on the bottom wall of the third groove. By providing a third groove in the wall body that is recessed from the fifth surface toward the electrode assembly, and providing a pressure relief groove on the bottom wall of the third groove to correspondingly form a pressure relief mechanism, the pressure relief mechanism is made closer to the electrode assembly than the fifth surface, and the implementation method is simple.

[0027] In some embodiments, the wall body is provided with a pressure relief groove to form a pressure relief mechanism at a position corresponding to the pressure relief groove on the wall body. By providing a pressure relief groove on the wall body to form an integral pressure relief mechanism, the forming method of the pressure relief mechanism is simple and the reliability of the pressure relief mechanism is higher.

[0028] In some embodiments, the battery cell further includes a current collector, which is disposed between the end wall and the electrode assembly along a first direction. The current collector electrically connects the electrode assembly and the end wall, and the abutment portion directly abuts against the current collector, which in turn directly abuts against the electrode tab. The current collector enables electrical connection between the electrode assembly and the end wall, reducing the difficulty of electrical connection between the electrode assembly and the end wall.

[0029] In some embodiments, the electrode assembly is provided with a first central hole, and the current collector is provided with a second central hole, the second central hole connecting the first central hole and the flow guiding space. In the event of thermal runaway of a battery cell, emissions generated by the electrode assembly can sequentially pass through the first and second central holes into the flow guiding space, further shortening the time from thermal runaway of the battery cell to the start of pressure relief by the pressure relief mechanism, allowing the pressure relief mechanism to be activated more promptly.

[0030] In some embodiments, the housing includes a shell and an end cap; the shell has an opening at at least one end along a first direction; the end cap closes the opening; wherein at least one end cap is an end wall, and the shell includes a side wall. The fact that at least one end cap is an end wall allows for the provision of a pressure relief mechanism, reducing the difficulty of molding or installing the pressure relief mechanism, and also allows a second flow channel to be disposed on the end cap, reducing the difficulty of molding the second flow channel.

[0031] In some embodiments, the battery cell is a cylindrical battery cell.

[0032] Secondly, embodiments of this application provide a battery, including the battery cell provided in any one of the embodiments of the first aspect.

[0033] Thirdly, embodiments of this application also provide an electrical device, including a battery cell improved in any of the embodiments of the first aspect, wherein the battery cell is used to provide electrical energy to the electrical device.

[0034] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0036] Figure 2 is an exploded view of a battery provided in some embodiments of this application;

[0037] Figure 3 is an exploded view of a single battery cell provided in some embodiments of this application;

[0038] Figure 4 is a cross-sectional view of the battery cell shown in Figure 3;

[0039] Figure 5 is a partial enlarged view of the battery cell shown in Figure 4;

[0040] Figure 6 is a schematic diagram of the end wall structure shown in Figure 5;

[0041] Figure 7 is an AA sectional view of the end wall shown in Figure 6;

[0042] Figure 8 is a view of the end wall shown in Figure 7 from direction B;

[0043] Figure 9 is a partially enlarged view of a battery cell provided in some other embodiments of this application;

[0044] Figure 10 is a magnified view of a portion of point C in Figure 9;

[0045] Figure 11 is a schematic diagram of the end wall structure shown in Figure 9;

[0046] Figure 12 is a DD cross-sectional view of the end wall shown in Figure 11.

[0047] Icons: 1-Outer shell; 11-Shell; 12-End cap; 13-End wall; 131-Wall body; 1311-Second surface; 1312-Fifth surface; 1313-Sixth surface; 1314-Third groove; 13141-Bottom wall of the third groove; 1315-Reinforcing rib; 1316-Pressure relief groove; 132-Abutting part; 1321-Second flow channel; 1322-Abutting surface; 1323-Protrusion; 13231-First end; 13232-Second end; 13233-First part; 13233a-Fourth surface; 13233b-First side surface; 13234-Second part; 13234a-Second side surface; 1324-Body part; 13241-First surface; 13242-Third surface; 1325-First groove; 13251-First stage groove; 13252-Second stage groove; 133-Guiding space; 134-Second groove; 135-Edge portion; 14-Side wall; 141-Inner circumferential surface; 2-Electrode assembly; 21-Electrode tab; 22-Main body portion; 23-First central hole; 3-Electrode terminal; 4-Current collector; 41-Second central hole; 5-Pressure relief mechanism; 6-First guiding channel; 7-Guiding gap; 10-Battery cell; 20-Box; 201-First box; 202-Second box; 100-Battery; 200-Controller; 300-Motor; 1000-Vehicle; Q-First circle; U-First connecting line; V-Second connecting line; X-First direction; Y-Circumferential direction of the abutment portion; Z-Radial direction of the abutment portion.

[0048] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0050] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0051] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation" and "connection" should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0052] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0053] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0054] In this application, "multiple" means two or more (including two).

[0055] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0056] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0057] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, reduces the risk of short circuits while allowing active ions to pass through.

[0058] In some embodiments, the positive electrode can be a positive electrode sheet, which may include a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0059] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0060] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0061] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0062] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0063] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative current collector.

[0064] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0065] As an example, the negative electrode sheet may include a negative current collector and a negative active material disposed on at least one surface of the negative current collector.

[0066] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0067] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0068] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0069] In some embodiments, the separator is a separator membrane. The separator membrane can be any known porous structure separator membrane with good chemical and mechanical stability.

[0070] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0071] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0072] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0073] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0074] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0075] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0076] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0077] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0078] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0079] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0080] In some embodiments, the electrode assembly is a wound structure. The positive electrode and the negative electrode are wound into a wound structure.

[0081] In some implementations, the electrode assembly is a stacked structure.

[0082] As an example, multiple positive and negative electrode plates can be set, and multiple positive and multiple negative electrode plates can be stacked alternately.

[0083] As an example, multiple positive electrode sheets can be set, and negative electrode sheets are folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments.

[0084] As an example, both the positive and negative electrode sheets are folded to form multiple stacked folded segments.

[0085] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0086] As an example, the separator can be continuously arranged between any adjacent positive or negative electrode plates by folding or rolling.

[0087] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0088] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0089] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0090] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells, such as hexagonal prismatic battery cells.

[0091] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0092] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0093] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0094] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0095] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0096] In some embodiments, to improve the reliability of a battery cell, a pressure relief mechanism can generally be provided on the end wall of the battery cell's casing. In the event of thermal runaway of the battery cell, the pressure inside the battery cell can be released through the pressure relief mechanism.

[0097] A pressure relief mechanism is a component or part that is activated to release internal pressure when the internal pressure of a battery cell reaches a predetermined threshold. This threshold design varies depending on design requirements. The threshold may depend on the materials of one or more of the components in the battery cell: the positive electrode, the negative electrode, the electrolyte, and the separator.

[0098] The term "actuation" as used in this application refers to the activation or actuation of the pressure relief mechanism to a certain state, thereby releasing the internal pressure of the battery cell. The actions of the pressure relief mechanism may include, but are not limited to, at least a portion of the mechanism rupturing, breaking, tearing, or opening. When the pressure relief mechanism is actuated, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the actuated portion. This method allows for pressure relief of the battery cell under controlled pressure, thereby preventing potentially more serious accidents.

[0099] The emissions from battery cells mentioned in the embodiments of this application include, but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of the separator, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0100] In a typical battery cell, a protruding abutment is formed on the end wall where a pressure relief mechanism is located, protruding towards the electrode assembly. This abutment directly or indirectly abuts against the electrode assembly's tabs to reduce the movement of the electrode assembly within the casing. However, because the abutment directly or indirectly abuts against the electrode assembly's tabs, in the event of thermal runaway in the battery cell, the discharge between the electrode assembly and the side wall of the casing may not reach the area where the pressure relief mechanism is located on the end wall. This prevents the pressure relief mechanism from activating in time, increasing the risk of battery cell explosion and fire, and affecting the reliability of the battery cell.

[0101] To address the issue of poor reliability in battery cells, this application provides a battery cell whose casing includes a wall body and abutment portion on its end wall. The wall body is equipped with a pressure relief mechanism, and the abutment portion is disposed around the outer edge of the wall body. The abutment portion protrudes from the wall body in a direction close to the electrode assembly and directly or indirectly abuts against the electrode assembly. A first flow channel is formed between the electrode assembly and the side wall of the casing. The abutment portion and the wall body together define a flow guiding space, and the abutment portion is provided with a second flow guiding channel, which connects the flow guiding space and the first flow guiding channel.

[0102] In such a battery cell, a second flow channel is provided in the abutment part, which connects the flow space and the first flow channel. When the battery cell experiences thermal runaway, the emissions generated by the electrode assembly flow into the first flow channel. The emissions can then quickly flow into the flow space through the second flow channel on the abutment part, causing the air pressure in the flow space to rise rapidly. This quickly reaches the burst pressure of the pressure relief mechanism, shortening the time from the battery cell's thermal runaway to the start of pressure relief through the pressure relief mechanism. This allows the pressure relief mechanism to be activated in a timely manner, reducing the risk of battery cell explosion and fire, and effectively improving the reliability of the battery cell.

[0103] The battery cells described in this application are applicable to batteries and electrical devices that use battery cells.

[0104] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.

[0105] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0106] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application. A battery 100 is disposed inside the vehicle 1000, and the battery 100 may be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000.

[0107] The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, for the power needs of the vehicle 1000 during startup, navigation and driving.

[0108] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0109] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of this application. The battery 100 includes a battery cell 10 and a housing 20, with the battery cell 10 housed within the housing 20.

[0110] The housing 20 is a component that houses the battery cell 10, providing a space for the battery cell 10. The housing 20 can adopt various structures. In some embodiments, the housing 20 may include a first housing 201 and a second housing 202, which overlap each other to define a space for accommodating the battery cell 10. The first housing 201 and the second housing 202 can have various shapes, such as cuboid or cylindrical. The first housing 201 can be a hollow structure open on one side, and the second housing 202 can also be a hollow structure open on one side, with the open side of the second housing 202 overlapping the open side of the first housing 201, thus forming a housing 20 with a accommodating space. Alternatively, the first housing 201 can be a hollow structure open on one side, and the second housing 202 can be a plate-like structure, with the second housing 202 overlapping the open side of the first housing 201, thus forming a housing 20 with a accommodating space. The first housing 201 and the second housing 202 can be sealed by a sealing element, such as a sealing ring or sealant.

[0111] In battery 100, there can be one or more battery cells 10. If there are multiple battery cells 10, they can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 10 are connected in both series and parallel. Alternatively, multiple battery cells 10 can be first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules can be connected in series, parallel, or in a mixed manner to form a whole, which is then housed within the housing 20. Another option is that all battery cells 10 can be directly connected in series, parallel, or in a mixed manner, and then the whole consisting of all battery cells 10 is housed within the housing 20.

[0112] Please refer to Figures 3 and 4. Figure 3 is an exploded view of a battery cell 10 provided in some embodiments of this application; Figure 4 is a cross-sectional view of the battery cell 10 shown in Figure 3. The battery cell 10 may include a housing 1 and an electrode assembly 2, the electrode assembly 2 being housed within the housing 1.

[0113] In some embodiments, the housing 1 may include a housing 11 and an end cap 12, the housing 11 having an opening and the end cap 12 closing the opening of the housing 11.

[0114] The housing 11 is a component used to house the electrode assembly 2. The housing 11 can be a hollow structure with an opening at one end, or a hollow structure with openings at both opposite ends. The housing 11 can be in various shapes, such as cylindrical or cuboid. The housing 11 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy.

[0115] End cap 12 is a component that closes the opening of housing 11 to isolate the internal environment of battery cell 10 from the external environment. End cap 12 and housing 11 together define a storage space for accommodating electrode assembly 2, electrolyte, and other components. End cap 12 can be connected to housing 11 by welding or roll sealing to close the opening of housing 11. The shape of end cap 12 can be adapted to the shape of housing 1. For example, if housing 11 is a cuboid structure, end cap 12 can be a rectangular plate structure adapted to housing 1; or if housing 11 is cylindrical, end cap 12 can be a circular plate structure adapted to housing 11. The material of end cap 12 can also be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The materials of end cap 12 and housing 11 can be the same or different.

[0116] In an embodiment where the housing 11 has an opening at one end, one end cap 12 may be provided accordingly. In an embodiment where the housing 11 has openings at both opposite ends, two end caps 12 may be provided accordingly. The two end caps 12 respectively close the two openings of the housing 11, and the two end caps 12 and the housing 11 together define the receiving space.

[0117] In some embodiments, the battery cell 10 may further include electrode terminals 3, which are disposed on the housing 1 and are used for electrical connection with the tabs 21 of the electrode assembly 2 to input or output electrical energy of the battery cell 10. The electrode terminals 3 may be disposed on the housing 11 of the housing 1 or on the end cap 12 of the housing 1. The electrode terminals 3 and the tabs 21 may be directly connected, for example, by welding. Alternatively, the electrode terminals 3 and the tabs 21 may be indirectly connected, for example, through a current collector 4. The current collector 4 may be a metallic conductor, such as copper, iron, aluminum, steel, or aluminum alloy.

[0118] As an example, in the embodiments shown in Figures 3 and 4, the battery cell 10 is a cylindrical battery cell, the housing 11 has an opening at only one end, and there is one end cap 12 that closes the opening of the housing 11. Electrode terminals 3 are provided on the walls of the housing 11 opposite to the end cap 12. The electrode assembly 2 has tabs 21 at both opposite ends. The tab 21 at one end of the electrode assembly 2 is the positive tab, and the tab 21 at the other end is the negative tab. The electrode terminal 3 is electrically connected to the positive tab through a current collector 4, and the end cap 12 is electrically connected to the negative tab through another current collector 4.

[0119] Please refer to Figures 5 and 6. Figure 5 is a partially enlarged view of the battery cell 10 shown in Figure 4; Figure 6 is a structural schematic diagram of the end wall 13 shown in Figure 5. This application provides a battery cell 10, which includes a housing 1 and an electrode assembly 2. The housing 1 includes an end wall 13 and a side wall 14. The end wall 13 is disposed at one end of the side wall 14 along a first direction X, and the side wall 14 surrounds the end wall 13. The electrode assembly 2 is housed within the housing 1. The end of the electrode assembly 2 facing the end wall 13 has a tab 21, and a first flow channel 6 is formed between the tab 21 and the side wall 14. The end wall 13 includes a wall body 131 and an abutment portion 132. The wall body 131 is provided with a pressure relief mechanism 5, and the abutment portion 132 is disposed around the outer edge of the wall body 131. Along the first direction X, the abutment portion 132 protrudes from the wall body 131 in a direction close to the electrode assembly 2 and directly or indirectly abuts against the tab 21. The abutment part 132 and the wall body 131 together define the flow guiding space 133. The abutment part 132 is provided with a second flow guiding channel 1321, which connects the flow guiding space 133 and the first flow guiding channel 6.

[0120] In embodiments where the housing 11 has an opening at only one end, the end cap 12 can serve as the end wall 13, and the side wall 14 can be part of the housing 11; alternatively, the wall portion of the housing 11 opposite to the end cap 12 can serve as the end wall 13, with the side wall 14 and the end wall 13 integrally formed to constitute the housing 11. In embodiments where both opposite ends of the housing 11 have openings, at least one of the two end caps 12 can serve as the end wall 13, and the side wall 14 can be the housing 11.

[0121] The sidewall 14 can be cylindrical, making the battery cell 10 a cylindrical battery cell; the sidewall 14 can also be cuboid, making the battery cell 10 a prismatic battery cell 10 or a blade battery cell 10. The sidewall 14 and the endwall 13 can be integrally formed, constituting the housing 11, with the end of the sidewall 14 away from the endwall 13 along the first direction X forming an opening in the housing 11; alternatively, the sidewall 14 and the endwall 13 can be separate components, with the endwall 13 serving as an end cap 12, and the end of the sidewall 14 near the endwall 13 along the first direction X forming an opening in the housing 11. In embodiments where the sidewall 14 and the endwall 13 are separate components, the endwall 13 and the sidewall 14 can be connected by welding, bonding, or roll sealing.

[0122] The electrode assembly 2 may further include a main body 22, with a tab 21 disposed at at least one end along the first direction X. The first flow channel 6 may be a gap formed between the outer peripheral surface of the tab 21 and the inner peripheral surface 141 of the sidewall 14. After the electrode assembly 2 is installed in the housing 1, a gap communicating with the first flow channel 6 may also be formed between the outer peripheral surface of the main body 22 and the inner peripheral surface 141 of the sidewall 14, through which emissions generated by thermal runaway of the electrode assembly 2 may enter the first flow channel 6. Of course, if the outer periphery of the main body 22 is covered with an insulating film, a gap communicating with the first flow channel 6 may be formed between the outer peripheral surface of the insulating film and the inner peripheral surface 141 of the sidewall 14. The inner peripheral surface 141 of the sidewall 14 is the surface of the sidewall 14 facing the electrode assembly 2, and the inner peripheral surface 141 may extend circumferentially around the opening of the housing 11. It is understandable that if the sidewall 14 is cylindrical, the inner circumferential surface 141 of the sidewall 14 is cylindrical; if the sidewall 14 is cuboid, the inner circumferential surface 141 of the sidewall 14 is cuboid.

[0123] The wall body 131 and the abutment part 132 can be integrally formed or they can be separate and connected. The pressure relief mechanism 5 can be a pressure relief component separately formed from the wall body 131, which is installed on the wall body 131. The pressure relief component can be an explosion-proof plate, a pressure relief valve, etc.; the pressure relief mechanism 5 can also be an integrally formed structure with the wall body 131. For example, the pressure relief mechanism 5 can be a weak part formed on the wall body 131. The weak part can be formed by setting a groove on the wall body 131, or by performing local heat treatment on the wall body 131 to weaken the strength of the local area, thereby forming a weak part.

[0124] The abutment portion 132 can be an annular structure surrounding the outer edge of the wall body 131. The annular structure can be a circular ring, a rectangular ring, etc. After the abutment portion 132 directly or indirectly abuts against the tab 21 of the electrode assembly 2, the abutment portion 132 and the electrode assembly 2 can be electrically connected or insulated. The tab 21 can be a positive or negative tab. If the abutment portion 132 directly abuts against the tab 21 of the electrode assembly 2, the abutment portion 132 and the tab 21 of the electrode assembly 2 are in direct contact. For example, the abutment portion 132 directly abuts against the tab 21 at the end of the electrode assembly 2 to achieve an electrical connection between the end wall 13 and the electrode assembly 2. If the abutment portion 132 indirectly abuts against the tab 21 of the electrode assembly 2, an intermediate component is provided between the abutment portion 132 and the electrode assembly 2. This intermediate component can be an insulating component or a conductive component. Taking the current collector 4 as an example, the abutment 132 can indirectly abut against the tab 21 at the end of the electrode assembly 2 through the current collector 4, so as to realize the electrical connection between the end wall 13 and the electrode assembly 2.

[0125] The flow guiding space 133, defined by the wall body 131 and the abutment portion 132, corresponds to the pressure relief mechanism 5. After the pressure relief mechanism 5 is actuated, the discharge within the flow guiding space 133 can be discharged to the outside of the battery cell 10 through the pressure relief mechanism 5. Along the first direction X, the flow guiding space 133 has an opening at the end of the abutment portion 132 near the electrode assembly 2. After the abutment portion 132 directly or indirectly abuts against the electrode assembly 2, the opening is covered. It can be understood that if the abutment portion 132 directly abuts against the electrode assembly 2, the opening of the flow guiding space 133 is covered by the electrode assembly 2; if the abutment portion 132 indirectly abuts against the electrode assembly 2 through an intermediate member, the opening of the flow guiding space 133 is covered by the intermediate member.

[0126] The second guide channel 1321 on the abutment part 132 can be one or more. If there are multiple second guide channels 1321, the multiple guide channels can be evenly distributed along the circumferential direction Y of the abutment part, or they can be non-uniformly distributed along the circumferential direction Y of the abutment part. The circumferential direction Y of the abutment part can be the circumferential direction of a circle surrounding a centerline extending along the first direction X.

[0127] The second flow channel 1321 can be a through hole that penetrates the abutment portion 132 radially Z-directed through the abutment portion, or it can be a notch groove that penetrates the abutment portion 132 radially Z-directed through the abutment portion and extends along the first direction X to one end of the abutment portion 132 near the electrode assembly 2.

[0128] In this embodiment, the abutment portion 132 of the end wall 13 directly or indirectly abuts against the tab 21 of the electrode assembly 2. The abutment portion 132 can restrict the electrode assembly 2, reducing the risk of the electrode assembly 2 moving along the first direction X within the housing 1. Since the abutment portion 132 is provided with a second flow channel 1321, which connects the flow space 133 and the first flow channel 6, when the battery cell 10 experiences thermal runaway, the emissions generated by the electrode assembly 2 flow into the first flow channel 6. The emissions can then quickly flow into the flow space 133 through the second flow channel 1321 on the abutment portion 132, causing the air pressure in the flow space 133 to rise rapidly. This quickly reaches the burst pressure of the pressure relief mechanism 5, shortening the time from the thermal runaway of the battery cell 10 to the start of pressure relief by the pressure relief mechanism 5. This allows the pressure relief mechanism 5 to be activated in a timely manner, reducing the risk of the battery cell 10 exploding or catching fire, and effectively improving the reliability of the battery cell 10.

[0129] In some embodiments, please continue to refer to FIG6, the abutment portion 132 is provided with a plurality of second flow channels 1321, and the plurality of second flow channels 1321 are arranged at Y intervals along the circumferential direction of the abutment portion.

[0130] The second flow channel 1321 on the abutment part 132 can be two, three, four, five, six or more.

[0131] As an example, the plurality of second guide channels 1321 on the abutment portion 132 are evenly distributed along the circumferential direction Y of the abutment portion, that is, the angle between any two adjacent second guide channels 1321 along the circumferential direction Y of the abutment portion is equal. Taking four second guide channels 1321 on the abutment portion 132 as an example, the distance between any two adjacent second guide channels 1321 along the circumferential direction Y of the abutment portion is 90°.

[0132] In this embodiment, the abutment portion 132 is provided with a plurality of second guide channels 1321 spaced at Y intervals along the circumference of the abutment portion, so that the discharge in the first guide channel 6 can enter the guide space 133 from the plurality of second guide channels 1321 at different positions, thereby increasing the rate at which the discharge in the first guide channel 6 enters the guide space 133 and further shortening the time from the thermal runaway of the battery cell 10 to the start of pressure relief of the battery cell 10 through the pressure relief mechanism 5.

[0133] In some embodiments, please continue to refer to FIG6. Along the first direction X, the abutment portion 132 has an abutment surface 1322, the abutment surface 1322 being the surface of the abutment portion 132 closest to the electrode assembly 2, and the second flow channel 1321 being a notch groove that penetrates the abutment portion 132 along the radial direction Z and extends to the abutment surface 1322 along the first direction X.

[0134] The abutment surface 1322 is both the surface of the abutment portion 132 closest to the electrode assembly 2 and the surface of the entire end wall 13 closest to the electrode assembly 2. The radial direction Z of the abutment portion is perpendicular to the first direction X. The notch groove penetrates the abutment portion 132 along the radial direction Z, thereby realizing the connection between the second flow channel 1321 and the flow channel 133 and the first flow channel 6. The notch groove extends to the abutment surface 1322 along the first direction X. The notch groove can be formed by recessing from the abutment surface 1322 in a direction away from the electrode assembly 2, and the notch groove forms a groove opening on the abutment surface 1322.

[0135] In an embodiment where the abutment portion 132 directly abuts against the tab 21 of the electrode assembly 2, the abutment surface 1322 may directly contact the tab 21 at the end of the electrode assembly 2, and the tab 21 may cover the notch groove formed in the abutment surface 1322; in an embodiment where the abutment portion 132 and the electrode assembly 2 indirectly abut against the electrode assembly 2 through an intermediate member, the abutment surface 1322 may directly contact the intermediate member, and the intermediate member may cover the notch groove formed in the abutment surface 1322.

[0136] In this embodiment, the second flow channel 1321 is a notch groove that penetrates the abutment portion 132 radially along the abutment portion and extends to the abutment surface 1322 along the first direction X. On the one hand, it can reduce the molding difficulty of the second flow channel 1321, and on the other hand, it is beneficial to increase the size of the second flow channel 1321 along the first direction X, thereby increasing the rate at which the discharge in the first flow channel 6 enters the flow space 133 through the second flow channel 1321.

[0137] In some embodiments, please continue to refer to Figures 5 and 6. The abutment portion 132 includes a plurality of protrusions 1323. The plurality of protrusions 1323 directly or indirectly abut against the tabs 21 of the electrode assembly 2. Along the circumferential Y direction of the abutment portion, a second flow channel 1321 is formed between two adjacent protrusions 1323.

[0138] The protrusions 1323 in the abutment portion 132 can be two, three, four, five, or more. The number of second flow channels 1321 is equal to the number of protrusions 1323, and they are alternately arranged along the circumferential Y direction of the abutment portion. As an example, the multiple protrusions 1323 in the abutment portion 132 are evenly distributed along the circumferential Y direction of the abutment portion, meaning that the angle between any two adjacent protrusions 1323 along the circumferential Y direction of the abutment portion is equal. Taking four protrusions 1323 in the abutment portion 132 as an example, the distance between any two adjacent protrusions 1323 along the circumferential Y direction of the abutment portion is 90°.

[0139] The protrusion 1323 is located inside the side wall 14. The protrusion 1323 can contact the inner surface of the side wall 14, and the two can also have a gap.

[0140] By forming a second flow channel 1321 between two adjacent protrusions 1323, the discharge in the first flow channel 6 can enter the flow space 133 from multiple second flow channels 1321 at different positions, increasing the rate at which the discharge in the first flow channel 6 enters the flow space 133. Furthermore, the second flow channel 1321 in this structure is a notch or groove formed on the abutment portion 132, which reduces the molding difficulty of the second flow channel 1321 and facilitates increasing the size of the second flow channel 1321 along the first direction X.

[0141] In some embodiments, please refer to FIG7, which is a cross-sectional view AA of the end wall 13 shown in FIG6. The protrusion 1323 has an abutment surface 1322, which is used to directly or indirectly abut against the tab 21 to achieve electrical connection between the end wall 13 and the electrode assembly 2. Along the first direction X, the height of the protrusion 1323 is H; along the radial direction Z of the abutment, the width of the abutment surface 1322 is W; 0.1W≤H≤0.5W.

[0142] In an embodiment where the abutment surface 1322 directly abuts against the tab 21 of the electrode assembly 2, the abutment surface 1322 may directly contact the tab 21 at the end of the electrode assembly 2 to achieve an electrical connection between the end wall 13 and the electrode assembly 2; in an embodiment where the abutment surface 1322 and the electrode assembly 2 indirectly abut against the tab 21 of the electrode assembly 2 through an intermediate component, the abutment surface 1322 may directly contact the intermediate component, the intermediate component being a conductive component, and the end wall 13 and the tab 21 of the electrode assembly 2 may be electrically connected through the intermediate component.

[0143] The height of the protrusion 1323 is equal to the depth of the notch (second flow channel 1321).

[0144] It is understandable that 0.1≤H / W≤0.5, and H / W can take any point value or a range between any two of the following: 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5.

[0145] By directly or indirectly abutting the tab 21 of the electrode assembly 2 with the abutting surface 1322, an electrical connection between the end wall 13 and the electrode assembly 2 can be achieved. In order to achieve stable overcurrent between the end wall 13 and the electrode assembly 2, the abutting surface 1322 generally has a certain width. Therefore, by controlling the height of the protrusion 1323 within the range of 0.1W to 0.5W, the dimensions of the second flow channel 1321 along the first direction X can meet the flow requirements, allowing the discharge in the first flow channel 6 to quickly enter the flow space 133 through the second flow channel 1321. At the same time, the impact of the excessive height of the protrusion 1323 on the volumetric energy density of the battery cell 10 can be reduced.

[0146] In some embodiments, along the first direction X, the height of the protrusion 1323 is H, where 5mm ≥ H ≥ 0.5mm.

[0147] H can be any one of the following values: 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, 5mm, or a range between any two.

[0148] In this embodiment, H ≥ 0.5 mm, ensuring that the dimension of the second flow channel 1321 along the first direction X is greater than or equal to 0.5 mm, thus meeting the flow requirements and allowing the discharge material in the first flow channel 6 to quickly enter the flow space 133 through the second flow channel 1321; H ≤ 5 mm, preventing the height of the protrusion 1323 from being too large, reducing the space occupied by the protrusion 1323 along the first direction X, which is beneficial to improving the volumetric energy density of the battery cell 10. In this way, both the flow requirements of the second flow channel 1321 and the volumetric energy density requirements of the battery cell 10 are considered.

[0149] In some embodiments, please refer to FIG8, which is a B-direction view of the end wall 13 shown in FIG7. Along the circumferential Y direction of the abutment portion, the protrusion 1323 has a first end 13231 and a second end 13232. The projection of the outer edge of the end wall 13 along the first direction X forms a first circle Q. When viewed along the first direction X, the line connecting the center of the first end 13231 and the first circle Q is the first connecting line U, and the line connecting the center of the second end 13232 and the first circle Q is the second connecting line V. The angle between the first connecting line U and the second connecting line V is α, where 15°≤α≤60°.

[0150] The angle between the first line U and the second line V is the central angle of the protrusion 1323. Both the first line U and the second line V are straight lines.

[0151] α can take any point value from 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, and 60°, or a range between any two.

[0152] By controlling α between 15° and 60°, more protrusions 1323 can be provided along the circumferential Y direction of the abutment to form more second guide channels 1321, so that the discharge in the first guide channel 6 can enter the guide space 133 from more positions.

[0153] In some embodiments, please continue to refer to Figure 8, along the circumferential Y direction of the abutment portion, a plurality of protrusions 1323 are evenly arranged.

[0154] It is understood that, along the circumferential Y direction of the abutment portion, the angle between any two adjacent protrusions 1323 is equal, and the angle β between any two adjacent protrusions 1323 is 360° / N, where N is the number of protrusions 1323. In the embodiment shown in Figure 8, N = 4, and β = 90°.

[0155] In this embodiment, multiple protrusions 1323 are evenly arranged along the circumferential Y direction of the abutment portion, so that multiple second guide channels 1321 on the abutment portion 132 can be evenly arranged along the circumferential Y direction of the abutment portion, so that the discharge in the second guide channel 1321 can enter the guide space 133 more evenly from the multiple guide channels, further increasing the rate at which the discharge in the first guide channel 6 enters the guide space 133.

[0156] In some embodiments, please refer to Figures 9 and 10. Figure 9 is a partially enlarged view of the battery cell 10 provided in other embodiments of this application; Figure 10 is a partially enlarged view of point C in Figure 9. A flow guiding gap 7 is formed between the sidewall 14 and the protrusion 1323 along the radial direction Z of the abutment portion. The flow guiding gap 7 connects two adjacent second flow guiding channels 1321.

[0157] The flow guide gap 7 is formed between the inner peripheral surface 141 of the sidewall 14 and the surface of the protrusion 1323 facing the inner peripheral surface 141 of the sidewall 14. Alternatively, the protrusion 1323 may not contact the inner peripheral surface 141 of the sidewall 14, thus forming the flow guide gap 7 between the protrusion 1323 and the sidewall 14. Or, a portion of the protrusion 1323 may contact the inner peripheral surface 141 of the sidewall 14, while another portion may not contact the inner peripheral surface 141 of the sidewall 14, thus forming the flow guide gap 7 between the protrusion 1323 and the sidewall 14.

[0158] The flow guide gap 7 between the side wall 14 and the protrusion 1323 can connect two adjacent second flow guide channels 1321. When the discharge in the first flow guide channel 6 flows to a certain second flow guide channel 1321, the discharge can flow through the flow guide gap 7 to another adjacent second flow guide channel 1321, so that the discharge in the first flow guide channel 6 can enter the flow guide space 133 more quickly.

[0159] For example, when the battery cell 10 experiences thermal runaway, if the thermal runaway area of ​​the electrode assembly 2 is close to a certain second flow channel 1321, the emissions generated by the thermal runaway of the electrode assembly 2 will flow towards the second flow channel 1321. If the second flow channel 1321 cannot guide the emissions into the flow space 133 in time, the emissions that do not enter the flow space 133 in time can flow through the flow gap 7 to another adjacent second flow channel 1321, and then quickly enter the flow space 133.

[0160] In some embodiments, please refer to Figures 10-12. Figure 11 is a structural schematic diagram of the end wall 13 shown in Figure 9; Figure 12 is a DD cross-sectional view of the end wall 13 shown in Figure 11. The abutment portion 132 also includes a body portion 1324, which is disposed around the outer edge of the wall body 131 and protrudes from the wall body 131 in a direction close to the electrode assembly 2. Along the first direction X, the body portion 1324 has a first surface 13241 facing the electrode assembly 2, and a protrusion 1323 is disposed on the first surface 13241.

[0161] The body portion 1324 may be an annular structure surrounding the outer edge of the wall body 131. The first surface 13241 may be the surface of the body portion 1324 closest to the electrode assembly 2 along the first direction X. A protrusion 1323 is provided on the first surface 13241 such that the protrusion 1323 extends from the first surface 13241 in the direction close to the electrode assembly 2. The second flow channel 1321 between two adjacent protrusions 1323 is a notch groove, and the bottom surface of the notch groove is located on the first surface 13241.

[0162] The main body 1324 and the wall body 131 can be integrally formed; the main body 1324 and the wall body 131 can also be separately provided and connected to each other, and the connection method can be welding, bonding, etc.; the protrusion 1323 and the main body 1324 can be integrally formed; the protrusion 1323 and the main body 1324 can also be separately provided and connected to each other, and the connection method can be welding, bonding, etc.

[0163] In this embodiment, the body portion 1324 serves to connect the wall body 131 and the protrusion 1323. The body portion 1324 is disposed around the wall body 131 and protrudes from the wall body 131 in a direction close to the electrode assembly 2, which can effectively improve the deformation resistance of the end wall 13.

[0164] In some embodiments, please continue to refer to Figures 10-12. Along the first direction X, the wall body 131 has a second surface 1311, which is the surface of the wall body 131 closest to the electrode assembly 2. The first surface 13241 is closer to the electrode assembly 2 than the second surface 1311.

[0165] Along the first direction X, the wall body 131 has a sixth surface 1313 facing the electrode assembly 2, and the body portion 1324 extends from the sixth surface 1313 in a direction closer to the electrode assembly 2. The second surface 1311 and the sixth surface 1313 can be the same surface or different surfaces. In the embodiment shown in FIG12, the second surface 1311 and the sixth surface 1313 are different surfaces, and along the first direction X, the second surface 1311 is closer to the electrode assembly 2 than the sixth surface 1313.

[0166] In this embodiment, the first surface 13241 is closer to the electrode assembly 2 than the second surface 1311, which can increase the distance between the second surface 1311 and the electrode assembly 2, reduce the influence of the electrode assembly 2 on the pressure relief mechanism 5 on the wall body 131, and effectively increase the size of the flow guiding space 133 along the first direction X.

[0167] In some embodiments, referring to FIG10, the abutment portion 132 is provided with a first groove 1325. Along the first direction X, the body portion 1324 has a third surface 13242 disposed opposite to the first surface 13241. The first surface 13241 is closer to the electrode assembly 2 than the third surface 13242. The first groove 1325 is recessed from the third surface 13242 toward the electrode assembly 2 to form a protrusion 1323 protruding from the first surface 13241 on the side of the body portion 1324 facing the electrode assembly 2.

[0168] The first groove 1325 corresponds one-to-one with the protrusion 1323. The first groove 1325 can be formed on the abutment 132 by stamping. By stamping the first groove 1325 on the third surface 13242, the protrusion 1323 protruding from the first surface 13241 of the body part 1324 can be formed accordingly, so that the protrusion 1323 and the body part 1324 are integrally formed. The first groove 1325 can be a single-level groove, which can be formed by a single stamping during the processing; the first groove 1325 can also be a multi-level groove, which can be formed step by step by multiple stampings during the processing.

[0169] By forming the protrusion 1323 by providing the first groove 1325 on the abutment portion 132, the forming difficulty of the protrusion 1323 can be effectively reduced, and the weight of the end wall 13 can be effectively reduced.

[0170] In some embodiments, please continue to refer to FIG10. The first groove 1325 is a multi-level groove. Along the first direction X, the first-level groove closer to the electrode assembly 2 in two adjacent grooves is disposed on the bottom surface of the first-level groove away from the electrode assembly 2.

[0171] It is understood that the first groove 1325 is a stepped groove. The first groove 1325 can be a two-level groove, a three-level groove, a four-level groove, a five-level groove, etc. As an example, in the embodiment shown in FIG10, the first groove 1325 is a two-level groove.

[0172] By setting the first groove 1325 as a multi-level groove, the forming force on the end wall 13 is lower when forming each level of groove, which reduces the risk of the end wall 13 being damaged due to excessive forming force when forming the first groove 1325.

[0173] In some embodiments, the protrusion 1323 includes a first portion 13233 and a second portion 13234, and the multi-level groove includes a first-level groove 13251 and a second-level groove 13252. The first-level groove 13251 is recessed from the third surface 13242 toward the electrode assembly 2 to form a first portion 13233 protruding from the first surface 13241 on the side of the body portion 1324 facing the electrode assembly 2. Along the first direction X, the first portion 13233 has a fourth surface 13233a facing the electrode assembly 2. The second-level groove 13252 is recessed from the bottom of the first-level groove 13251 toward the direction toward the electrode assembly 2 to form a second portion 13234 protruding from the fourth surface 13233a on the side of the first portion 13233 facing the electrode assembly 2.

[0174] It should be noted that the protrusion 1323 may include only the first part 13233 and the second part 13234, or it may include other parts besides the first part 13233 and the second part 13234. If the protrusion 1323 includes only the first part 13233 and the second part 13234, along the first direction, the sum of the heights of the first part 13233 and the second part 13234 is equal to the height H of the protrusion 1323. The multi-level groove may include only the first-level groove 13251 and the second-level groove 13252, or it may include other levels of grooves besides the first-level groove 13251 and the second-level groove 13252. Taking the multi-level groove including only the first-level groove 13251 and the second-level groove 13252 as an example, both the first-level groove 13251 and the second-level groove 13252 can be stamped. During the forming process, a first-level groove 13251 can be stamped out on the third surface 13242 to form a first part 13233 protruding from the first surface 13241; then a second-level groove 13252 can be stamped out on the bottom surface of the first-level groove 13251 to form a second part 13234 protruding from the fourth surface 13233a of the first part 13233, thus finally forming the first groove 1325 and the protrusion 1323.

[0175] The first part 13233 and the second part 13234 are both located inside the side wall 14. The first part 13233 can contact the inner surface of the side wall 14, and there can also be a gap between them. The second part 13234 can contact the inner surface of the side wall 14, and there can also be a gap between them.

[0176] In this embodiment, by providing a first-level groove 13251 on the body portion 1324, a first portion 13233 of the protrusion 1323 can be formed accordingly, and by providing a second-level groove 13252 on the first portion 13233, a second portion 13234 of the protrusion 1323 can be formed accordingly, thereby reducing the molding difficulty of the protrusion 1323.

[0177] In some embodiments, referring to FIG10, along the radial direction Z of the abutment portion, the first portion 13233 has a first side surface 13233b facing the inner peripheral surface 141 of the sidewall 14, and the second portion 13234 has a second side surface 13234a facing the inner peripheral surface 141 of the sidewall 14. The first side surface 13233b is closer to the inner peripheral surface 141 of the sidewall 14 than the second side surface 13234a. A flow guiding gap 7 is formed between the second side surface 13234a and the inner peripheral surface 141 of the sidewall 14, and the flow guiding gap 7 connects two adjacent second flow guiding channels 1321.

[0178] A flow guiding gap 7 is formed between the second side surface 13234a and the inner peripheral surface 141 of the side wall 14, meaning that the second side surface 13234a and the inner peripheral surface 141 of the side wall 14 are not in contact. Of course, a flow guiding gap 7 can also be formed between the first side surface 13233b and the inner peripheral surface 141 of the side wall 14, or they can be in direct contact.

[0179] As an example, both the first side surface 13233b and the second side surface 13234a are arc surfaces whose central axis extends along the first direction X, and the central axis of both the first side surface 13233b and the second side surface 13234a coincides with the central axis of the inner circumferential surface 141 of the side wall 14.

[0180] In this embodiment, the flow guide gap 7 between the second side surface 13234a and the inner peripheral surface 141 of the side wall 14 can connect two adjacent second flow guide channels 1321. When the discharge in the first flow guide channel 6 flows to a certain second flow guide channel 1321, the discharge can flow to another adjacent second flow guide channel 1321 through the flow guide gap 7, so that the discharge in the first flow guide channel 6 can enter the flow guide space 133 more quickly.

[0181] In some embodiments, please continue to refer to FIG10, a second groove 134 is provided on the side of the end wall 13 away from the electrode assembly 2 and corresponding to the body portion 1324, and the third surface 13242 is the bottom surface of the second groove 134.

[0182] As an example, the second groove 134 has the same shape as the body portion 1324, both being annular structures.

[0183] The second groove 134 can be formed on the end wall 13 by stamping. By stamping the second groove 134 on one side of the end wall 13, a corresponding groove 1324 can be formed on the other side of the end wall 13, thus achieving integral forming of the wall body 131 and the body body 1324. During forming, the second groove 134 can be stamped on the end wall 13 first, and then the first groove 1325 can be stamped on the bottom surface of the second groove 134.

[0184] In this embodiment, the body portion 1324 is formed by providing a second groove 134 on the end wall 13, which effectively reduces the molding difficulty of the body portion 1324.

[0185] In some embodiments, please continue to refer to FIG10, the end wall 13 and the side wall 14 are separately provided, and at least a portion of the body portion 1324 is accommodated in the side wall 14 and forms a positioning fit with the side wall 14.

[0186] The end wall 13 and the side wall 14 are separate parts, meaning that the end wall 13 and the side wall 14 are not integrally formed. As an example, the end wall 13 is the end cap 12 in the outer shell 1, and the end wall 13 and the side wall 14 are welded together.

[0187] The portion of the body portion 1324 housed within the side wall 14 forms a positioning fit with the side wall 14, such that the outer peripheral surface of the body portion 1324 is in contact with the inner peripheral surface 141 of the side wall 14. As an example, the portion of the body portion 1324 housed within the side wall 14 forms an interference fit with the side wall 14.

[0188] In this embodiment, the positioning fit between the body portion 1324 and the side wall 14 effectively reduces the assembly difficulty of the end wall 13 and the side wall 14. Taking the welding connection between the end wall 13 and the side wall 14 as an example, during the assembly process, after the positioning fit between the body portion 1324 and the side wall 14 is formed, it is easier to weld the end wall 13 and the side wall 14 together, reducing the welding difficulty and improving the welding quality.

[0189] In some embodiments, please continue to refer to FIG10, the end wall 13 further includes an edge portion 135, which is disposed around the outer edge of the body portion 1324, and the edge portion 135 abuts against one end of the side wall 14 in the direction of the end wall 13 pointing toward the electrode assembly 2.

[0190] The edge portion 135 is an annular structure surrounding the outer edge of the body portion 1324. The outer edge of the edge portion 135 is the outer edge of the end wall 13.

[0191] As an example, the sidewall 14 is part of the housing 1, the housing 1 has an opening at only one end along the first direction X, and the edge portion 135 abuts against the end of the housing 1 with the opening in the direction of the end wall 13 pointing toward the electrode assembly 2, and the edge portion 135 is welded to the sidewall 14.

[0192] In this embodiment, the edge portion 135 abuts against the sidewall 14 to limit the end wall 13 and restrict the end wall 13 from moving in the direction close to the electrode assembly 2.

[0193] In some embodiments, the wall body 131 and the abutment portion 132 are integrally formed.

[0194] As an example, a second groove 134 is provided on the side of the end wall 13 away from the electrode assembly 2, corresponding to the abutment portion 132, and the second groove 134 is formed by stamping.

[0195] In embodiments where the end wall 13 also includes an edge portion 135, the edge portion 135, the abutment portion 132, and the wall body 131 can be integrally formed.

[0196] In this embodiment, the wall body 131 and the abutment part 132 are integrally formed, which can effectively improve the connection strength between the abutment part 132 and the wall body 131.

[0197] In some embodiments, referring to FIG12, along the first direction X, the wall body 131 has a fifth surface 1312, which is the surface of the end wall 13 furthest from the electrode assembly 2, and the pressure relief mechanism 5 is closer to the electrode assembly 2 than the fifth surface 1312 (not shown in FIG12).

[0198] The fifth surface 1312 may be the end face of one end of the battery cell 10 along the first direction X. The fifth surface 1312 is used to contact external components. In the embodiment where the end wall 13 is electrically connected to the electrode assembly 2, the end wall 13 serves as an output electrode of the battery cell 10, and the external component may be a busbar component for electrical connection with the end wall 13; in the embodiment where the end wall 13 is insulated from the electrode assembly 2, the end wall 13 may be a component located in the bottom region of the battery cell 10, and the external component may be the housing 20 in the battery 100. After the battery cell 10 is placed inside the housing 20, the fifth surface 1312 may serve as the lower end face of the battery cell 10 and contact the housing 20.

[0199] It should be noted that, in this embodiment, the pressure relief mechanism 5 can be a pressure relief component that is separately provided from the wall body 131, or the pressure relief mechanism 5 can be a structure integrally formed with the wall body 131.

[0200] In this embodiment, the pressure relief mechanism 5 is closer to the electrode assembly 2 than the fifth surface 1312, which increases the distance between the pressure relief mechanism 5 and the external component when the fifth surface 1312 contacts the external component, reduces the impact of the external component on the pressure relief mechanism 5, and reduces the risk of the pressure relief mechanism 5 being prematurely activated by the impact force of the external component.

[0201] In some embodiments, please continue to refer to FIG12, the wall body 131 is provided with a third groove 1314, the third groove 1314 is recessed from the fifth surface 1312 toward the direction close to the electrode assembly 2, and the bottom wall 13141 of the third groove is provided with a pressure relief groove 1316, so that a pressure relief mechanism 5 is formed at the position corresponding to the bottom wall 13141 of the third groove and the pressure relief groove 1316.

[0202] The third groove 1314 can be stamped into the wall body 131. The projection of the third groove 1314 along the first direction X can be rectangular, circular, elliptical, etc. The bottom wall 13141 of the third groove is the part of the wall body 131 located at the bottom of the third groove 1314 along the depth direction of the third groove 1314.

[0203] The pressure relief groove 1316 can be set on the side of the bottom wall 13141 of the third groove facing the electrode assembly 2, or it can be set on the side of the bottom wall 13141 of the third groove away from the electrode assembly 2.

[0204] By providing a pressure relief groove 1316 on the bottom wall 13141 of the third groove, a pressure relief mechanism 5 is integrally formed with the wall body 131. The pressure relief mechanism 5 is the bottom wall of the pressure relief groove 1316, which is the portion of the bottom wall 13141 of the third groove located at the bottom of the pressure relief groove 1316 along the depth direction of the pressure relief groove 1316.

[0205] As an example, as shown in Figure 12, the bottom wall 13141 of the third groove has a recess on the side facing away from the electrode assembly 2. A reinforcing rib 1315 is formed on the side of the bottom wall 13141 facing the electrode assembly 2, corresponding to the recess. The reinforcing rib 1315 is approximately X-shaped along the first direction X. The surface of the end of the reinforcing rib 1315 facing the electrode assembly 2 is the surface of the wall body 131 closest to the electrode assembly 2 (second surface 1311). The pressure relief groove 1316 is an annular groove surrounding the outside of the reinforcing rib 1315, defining a pressure relief area. The reinforcing rib 1315 is located within the pressure relief area. When the battery cell 10 is depressurized, the wall body 131 will crack along the pressure relief groove 1316, thereby opening the pressure relief area. The reinforcing rib 1315 strengthens the pressure relief area, improves its resistance to deformation, and reduces the risk of premature failure of the pressure relief mechanism 5 due to fatigue caused by deformation of the pressure relief area caused by changes in the internal pressure of the battery cell 10.

[0206] In this embodiment, by providing a third groove 1314 recessed from the fifth surface 1312 toward the electrode assembly 2 in the wall body 131, and providing a pressure relief groove 1316 in the bottom wall 13141 of the third groove to form a corresponding pressure relief mechanism 5, the pressure relief mechanism 5 is closer to the electrode assembly 2 than the fifth surface 1312, and the implementation method is simple.

[0207] In some embodiments, the wall body 131 is provided with a pressure relief groove 1316 to form a pressure relief mechanism 5 at a position corresponding to the pressure relief groove 1316 on the wall body 131.

[0208] There are various forming methods for the pressure relief groove 1316, such as stamping, laser etching, and milling. The pressure relief groove 1316 can be a groove extending along a closed trajectory, which can be a circular trajectory, a rectangular trajectory, etc.; the pressure relief groove 1316 can also be a groove extending along a non-closed trajectory, which can be an H-shaped trajectory, a V-shaped trajectory, a C-shaped trajectory, a Y-shaped trajectory, etc.

[0209] An integrated pressure relief mechanism 5 is formed by setting a pressure relief groove 1316 on the wall body 131. The forming method of the pressure relief mechanism 5 is simple and the reliability of the pressure relief mechanism 5 is higher.

[0210] In some embodiments, please continue to refer to FIG9, the battery cell 10 may further include a current collector 4, which is disposed between the end wall 13 and the electrode assembly 2 along the first direction X. The current collector 4 is electrically connected to the electrode assembly 2 and the end wall 13. The abutment portion 132 directly abuts against the current collector 4, and the current collector 4 directly abuts against the tab 21.

[0211] The current collector 4 is a conductive component that enables the electrical connection between the electrode assembly 2 and the end wall 13. The current collector 4 is located inside the housing 1 and between the end wall 13 and the electrode assembly 2. The current collector 4 can be welded to the tab 21 at the end of the electrode assembly 2, or it can be welded to the abutment part 132.

[0212] In this embodiment, the abutment part 132 indirectly abuts against the tab 21 of the electrode assembly 2 through the current collector 4. The current collector 4 enables the electrical connection between the electrode assembly 2 and the end wall 13, reducing the difficulty of the electrical connection between the electrode assembly 2 and the end wall 13.

[0213] In some embodiments, the electrode assembly 2 is provided with a first central hole 23, and the current collecting member 4 is provided with a second central hole 41, the second central hole 41 connecting the first central hole 23 and the current guiding space 133.

[0214] As an example, electrode assembly 2 is a wound structure, with the first central hole 23 located at the winding center of the wound structure. Both the first central hole 23 and the second central hole 41 are cylindrical holes, and the first central hole 23 and the second central hole 41 are coaxially arranged, with the diameter of the first central hole 23 being larger than the diameter of the second central hole 41.

[0215] When the battery cell 10 experiences thermal runaway, the emissions generated by the electrode assembly 2 can sequentially enter the flow guiding space 133 through the first central hole 23 and the second central hole 41, further shortening the time from the thermal runaway of the battery cell 10 to the start of pressure relief by the pressure relief mechanism 5, so that the pressure relief mechanism 5 can be activated more promptly.

[0216] In some embodiments, the housing 1 includes a housing 11 and an end cap 12. The housing 11 has an opening at at least one end along a first direction X, and the end cap 12 closes the opening. At least one end cap 12 is an end wall 13, and the housing 11 includes a side wall 14.

[0217] The housing 11 may have an opening at only one end along the first direction X, with one end cap 12 correspondingly provided. Alternatively, the housing 11 may have openings at both ends along the first direction X, with two end caps 12 correspondingly provided. The two end caps 12 respectively close the two opposite openings of the housing 11. One end cap 12 may be an end wall 13, or both end caps 12 may be end walls 13. It is understood that the end wall 13 and the side wall 14 are separately provided.

[0218] In this embodiment, at least one end cap 12 is an end wall 13, which enables at least one end cap 12 to be provided with a pressure relief mechanism 5, reducing the molding or installation difficulty of the pressure relief mechanism 5, and enabling the second flow channel 1321 to be provided on the end cap 12, reducing the molding difficulty of the second flow channel 1321.

[0219] In some embodiments, the battery cell 10 is a cylindrical battery cell.

[0220] It is understood that the battery cell 10 is cylindrical, and the axis of the battery cell 10 is parallel to the first direction X.

[0221] This application provides a battery 100, including the battery cell 10 provided in any of the above embodiments.

[0222] This application also provides an electrical device, including a battery cell 10 as described in any of the above embodiments, wherein the battery cell 10 is used to provide electrical energy to the electrical device.

[0223] Furthermore, referring to Figures 3-7, this embodiment of the application also provides a cylindrical battery cell, including a housing 1, an electrode assembly 2, and a current collector 4, both of which are housed within the housing 1. The housing 1 includes a shell 11 and an end cap 12. The shell 11 has an opening at only one end along a first direction X, and the end cap 12 closes the opening. The first direction X is parallel to the axial direction of the housing 1. The electrode assembly 2 includes a main body 22 and tabs 21. Tabs 21 are provided at both ends of the main body 22 along the first direction X, and the tabs 21 at both ends of the main body 22 are a positive tab and a negative tab, respectively. Electrode terminals 3 are provided on the wall portion of the shell 11 opposite to the end cap 12. The electrode terminals 3 are electrically connected to the positive tab through a current collector 4, and the end cap 12 is electrically connected to the negative tab through another current collector 4.

[0224] The end cap 12 is the end wall 13 of the outer shell 1. The outer shell 11 includes side walls 14 surrounding the end wall 13. A first flow channel 6 is formed between the negative electrode tab of the electrode assembly 2 and the side wall 14. The end wall 13 includes a wall body 131 and an abutment portion 132. The wall body 131 is provided with a pressure relief groove 1316 to form a pressure relief mechanism 5 at a position corresponding to the pressure relief groove 1316. The abutment portion 132 is arranged around the outer edge of the wall body 131. Along the first direction X, the abutment portion 132 protrudes from the wall body 131 in the direction close to the electrode assembly 2 and directly abuts against the current collecting member 4. The abutment portion 132 and the wall body 131 together define a flow guiding space 133. The abutment portion 132 is provided with a second flow guiding channel 1321, which connects the flow guiding space 133 and the first flow guiding channel 6.

[0225] The abutment portion 132 includes a body portion 1324 and a plurality of protrusions 1323. The body portion 1324 is disposed around the outer edge of the wall body 131 and protrudes from the wall body 131 in a direction close to the electrode assembly 2. In the first direction X, the body portion 1324 has a first surface 13241 facing the electrode assembly 2. The protrusions 1323 are disposed on the first surface 13241 and directly abut against the current collector 4. A second groove 134 is provided on the side of the end wall 13 away from the electrode assembly 2, corresponding to the position of the body portion 1324. The abutment portion 132 is provided with a first groove 1325. In the first direction X, the first groove 1325 is recessed from the bottom surface of the second groove 134 in a direction close to the electrode assembly 2, so as to form a protrusion 1323 protruding from the first surface 13241 on the side of the body portion 1324 facing the electrode assembly 2. Multiple protrusions 1323 are evenly distributed along the circumferential Y direction of the abutment, and a second flow channel 1321 is formed between two adjacent protrusions 1323. The height of the protrusion 1323 along the first direction X is H; the protrusion 1323 has an abutment surface 1322 that directly abuts against the flow collecting member 4, and the width of the abutment surface 1322 along the radial direction Z of the abutment is W; 0.1W≤H≤0.5W, 5mm≥H≥0.5mm.

[0226] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0227] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit this application. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

A single battery cell, comprising: The housing includes an end wall and a side wall, the end wall being disposed at one end of the side wall along a first direction, and the side wall surrounding the end wall; An electrode assembly is housed within the housing. One end of the electrode assembly facing the end wall has a tab, and a first flow channel is formed between the tab and the side wall. The end wall includes a wall body and abutment portions. The wall body is provided with a pressure relief mechanism, and the abutment portions are arranged around the outer edge of the wall body. Along the first direction, the abutment portions protrude from the wall body in a direction close to the electrode assembly and directly or indirectly abut against the tab. The abutment portions and the wall body together define a flow space, and the abutment portions are provided with a second flow channel, which connects the flow space and the first flow channel. The battery cell as described in claim 1, wherein, The abutting part is provided with a plurality of second flow channels, which are spaced apart along the circumference of the abutting part. The battery cell as described in claim 1 or 2, wherein, Along the first direction, the abutting portion has an abutting surface, which is the surface of the abutting portion closest to the electrode assembly, and the second flow channel is a notch groove that penetrates the abutting portion radially and extends along the first direction to the abutting surface. The battery cell according to any one of claims 1-3, wherein, The abutting part includes: a plurality of protrusions that directly or indirectly abut against the tab, and a second flow channel is formed between two adjacent protrusions along the circumference of the abutting part. The battery cell as described in claim 4, wherein, The protrusion has a contact surface for directly or indirectly contacting the tab to achieve electrical connection between the end wall and the electrode assembly; the height of the protrusion is H along the first direction; the width of the contact surface is W along the radial direction of the contact portion. 0.1W≤H≤0.5W. The battery cell as described in claim 4 or 5, wherein, Along the first direction, the height of the protrusion is H, where 5mm ≥ H ≥ 0.5mm. The battery cell according to any one of claims 4-6, wherein, Along the circumference of the abutment portion, the protrusion has a first end and a second end opposite to each other; the projection of the outer edge of the end wall along the first direction forms a first circle, and when viewed along the first direction, the line connecting the first end and the center of the first circle is a first line, and the line connecting the second end and the center of the first circle is a second line, and the angle between the first line and the second line is α, where 15°≤α≤60°. The battery cell according to any one of claims 4-7, wherein, Along the circumference of the abutment portion, a plurality of protrusions are evenly arranged. The battery cell according to any one of claims 4-8, wherein, Along the radial direction of the abutment portion, a flow guiding gap is formed between the sidewall and the protrusion; the flow guiding gap connects two adjacent second flow guiding channels. The battery cell according to any one of claims 4-9, wherein, The abutment portion further includes: a body portion, which is disposed around the outer edge of the wall body and protrudes from the wall body in a direction close to the electrode assembly. Along the first direction, the body portion has a first surface facing the electrode assembly, and the protrusion is disposed on the first surface. The battery cell as described in claim 10, wherein, Along the first direction, the wall body has a second surface, which is the surface of the wall body closest to the electrode assembly, and the first surface is closer to the electrode assembly than the second surface. The battery cell as described in claim 10 or 11, wherein, The abutment portion is provided with a first groove; along the first direction, the body portion has a third surface disposed opposite to the first surface, the first surface being closer to the electrode assembly than the third surface, and the first groove being recessed from the third surface toward the electrode assembly to form a protrusion protruding from the first surface on the side of the body portion facing the electrode assembly. The battery cell as described in claim 12, wherein, The first groove is a multi-level groove. Along the first direction, the first-level groove of two adjacent grooves that is closer to the electrode assembly is located on the bottom surface of the first-level groove that is farther away from the electrode assembly. The battery cell as described in claim 13, wherein, The protrusion includes a first portion and a second portion, and the multi-level groove includes: a first-level groove that is recessed from the third surface toward the electrode assembly to form a first portion protruding from the first surface on the side of the body portion facing the electrode assembly, the first portion having a fourth surface facing the electrode assembly along the first direction; and a second-level groove that is recessed from the bottom of the first-level groove toward the electrode assembly to form a second portion protruding from the fourth surface on the side of the first portion facing the electrode assembly. The battery cell as described in claim 14, wherein, Along the radial direction of the abutment portion, the first portion has a first side surface facing the inner circumferential surface of the sidewall, and the second portion has a second side surface facing the inner circumferential surface of the sidewall. The first side surface is closer to the inner circumferential surface of the sidewall than the second side surface. A flow guiding gap is formed between the second side surface and the inner circumferential surface of the sidewall, and the flow guiding gap connects two adjacent second flow guiding channels. The battery cell according to any one of claims 12-15, wherein, A second groove is provided on the side of the end wall opposite to the electrode assembly, corresponding to the body portion, and the third surface is the bottom surface of the second groove. The battery cell according to any one of claims 10-16, wherein, The end wall and the side wall are separately provided, and at least a portion of the main body is accommodated in the side wall and forms a positioning fit with the side wall. The battery cell as described in claim 17, wherein, The end wall also includes an edge portion, which is disposed around the outer edge of the body portion and abuts against one end of the side wall in the direction of the end wall toward the electrode assembly. The battery cell according to any one of claims 1-18, wherein, The wall body and the abutment part are integrally formed. The battery cell as described in any one of claims 1-19, wherein, Along the first direction, the wall body has a fifth surface, which is the surface of the end wall furthest from the electrode assembly, and the pressure relief mechanism is closer to the electrode assembly than the fifth surface. The battery cell as described in claim 20, wherein, The wall body is provided with a third groove, which is recessed from the fifth surface toward the electrode assembly. The bottom wall of the third groove is provided with a pressure relief groove, so as to form the pressure relief mechanism at the position corresponding to the pressure relief groove on the bottom wall of the third groove. The battery cell according to any one of claims 1-20, wherein, The wall body is provided with a pressure relief groove, so that the pressure relief mechanism is formed at the position of the wall body corresponding to the pressure relief groove. The battery cell according to any one of claims 1-22, wherein, The battery cell further includes: a current collector, disposed along the first direction between the end wall and the electrode assembly, the current collector being electrically connected to the electrode assembly and the end wall, the abutment portion directly abutting against the current collector, and the current collector directly abutting against the tab. The battery cell as described in claim 23, wherein, The electrode assembly is provided with a first central hole, and the current collecting component is provided with a second central hole, the second central hole connecting the first central hole and the current guiding space. The battery cell according to any one of claims 1-24, wherein, The outer casing includes: a housing having an opening at at least one end along the first direction; an end cap closing the opening; wherein at least one of the end caps is the end wall, and the housing includes the side wall. The battery cell as described in any one of claims 1-25, wherein, The battery cell is a cylindrical battery cell. A battery comprising a battery cell as described in any one of claims 1-26. An electrical device includes a battery cell as described in any one of claims 1-26, the battery cell being used to provide electrical energy to the electrical device.

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