Battery cells, batteries, and electrical devices

Abstract

Embodiments of the present application provide a battery cell, a battery, and an electric device. The battery cell comprises a housing and an electrode assembly. The housing comprises a end wall and a side wall, wherein the end wall is installed at one end along a first direction of the side wall and the side wall is installed surrounding the end wall. An electrode assembly is accommodated within the housing, and a first flow path is formed between a tab at one end of the electrode assembly facing the end wall and the side wall. The end wall comprises a wall body and a contact portion, wherein a pressure relief mechanism is installed in the wall body and the contact portion is installed surrounding the outer edge of the wall body. Along the first direction, the contact portion protrudes from the wall body along a direction adjacent to the electrode assembly and contacts the tab directly or indirectly. The contact portion and the wall body jointly define a flow space, and a second flow path is installed in the contact portion, wherein the second flow path communicates the flow space and the first flow path. When thermal runaway occurs in the battery cell, the discharge generated from the electrode assembly rapidly flows into the current-conducting space through the second current-conducting passage on the contact part, thereby effectively improving the reliability of the battery cell.

Description

Technology Field

[0001] This application relates to the field of battery technology, specifically to battery cells, batteries, and electrical devices. Background Technology

[0002] In recent years, new energy vehicles have advanced rapidly, and in the field of electric vehicles, power batteries play an irreplaceable and important role as the power source for electric vehicles. With the active adoption of new energy vehicles, the demand for power battery products is increasing day by day. As the demand for batteries increases, it has placed higher demands on the reliability of battery cells. Therefore, improving the reliability of battery cells is an urgent challenge that must be addressed in battery technology. The problem to be solved

[0003] The embodiments of the present application provide a battery cell, a battery, and an electric device that can effectively improve the reliability of the battery cell. means of solving the problem

[0004] According to a first aspect, an embodiment of the present application provides a battery cell comprising a housing and an electrode assembly; the housing comprises a end wall and a side wall, the end wall is installed at one end along a first direction of the side wall, and the side wall is installed surrounding the end wall; the electrode assembly is accommodated within the housing, and one end of the electrode assembly facing the end wall has a tab, and a first flow path is formed between the tab and the side wall, wherein the end wall comprises a wall body and a contact portion, a pressure relief mechanism is installed in the wall body, and the contact portion is installed surrounding the outer edge of the wall body; along the first direction, the contact portion protrudes from the wall body along a direction adjacent to the electrode assembly and is in direct or indirect contact with the tab; the contact portion and the wall body jointly define a flow space, and a second flow path is installed in the contact portion, and the second flow path communicates the flow space and the first flow path.

[0005] In the technical solution described above, the contact portion of the end wall is contacted directly or indirectly to the tab, and the contact portion can restrict the electrode assembly and reduce the risk of the electrode assembly moving along a first direction within the housing. A second flow path is installed in the contact portion, and the second flow path communicates the flow space and the first flow path. When thermal runaway occurs in the battery cell, the discharge generated from the electrode assembly flows into the first flow path, and then the discharge can rapidly flow into the flow space through the second flow path on the contact portion. This rapidly increases the air pressure within the flow space, quickly reaching the burst pressure of the pressure release mechanism. This shortens the time from the occurrence of thermal runaway in the battery cell to the start of pressure release from the battery cell through the pressure release mechanism, thereby enabling the pressure release mechanism to operate in a timely manner, reducing the risk of battery cell explosion and ignition, and effectively improving the reliability of the battery cell.

[0006] In some embodiments, a plurality of second flow passages are installed in the contact portion, and the plurality of second flow passages are spaced apart along the circumferential direction of the contact portion. By allowing the discharge from the first flow passage to flow into the flow space from a plurality of second flow passages located at different positions, the rate at which the discharge from the first flow passage flows into the flow space is improved, and the time from the occurrence of thermal runaway of the battery cell to the start of pressure release of the battery cell through the pressure release mechanism is further shortened.

[0007] In some embodiments, along the first direction, the contact portion has a contact surface, the contact surface being the surface of the contact portion closest to the electrode assembly, and the second flow path is a notch groove that penetrates the contact portion along the radial direction of the contact portion and extends to the contact surface along the first direction. In this way, on the one hand, the difficulty of forming the second flow path can be reduced, and on the other hand, it is advantageous to increase the dimensions of the second flow path along the first direction to improve the speed at which the discharge in the first flow path flows into the flow space through the second flow path.

[0008] In some embodiments, the contact portion includes a plurality of protrusions, and the plurality of protrusions contact the tab directly or indirectly, and a second flow passage is formed between two adjacent protrusions along the circumferential direction of the contact portion. By forming a second flow passage between two adjacent protrusions, discharges within the first flow passage can flow into the flow space from a plurality of second flow passages located at different positions, thereby improving the speed at which discharges within the first flow passage flow into the flow space. Furthermore, the second flow passage having this structure is a notch groove formed in the contact portion, which not only reduces the difficulty of forming the second flow passage but is also advantageous for increasing the dimensions along the first direction of the second flow passage.

[0009] In some embodiments, the protrusion has a contact surface, and the contact surface is used to achieve an electrical connection between the end wall and the electrode assembly by contacting the tab directly or indirectly; along the first direction, the height of the protrusion is H; along the radial direction of the contact surface, the width of the contact surface is W; and 0.1W ≤ H ≤ 0.5W. By contacting the contact surface directly or indirectly with the tab, an electrical connection between the end wall and the electrode assembly can be achieved, and to achieve a stable current between the end wall and the electrode assembly, the contact surface generally has a constant width, and thus, the height of the protrusion is controlled within the range of 0.1W to 0.5W so that the dimensions along the first direction of the second current path can satisfy the current flow requirements, and so that the discharge in the first current path can be rapidly introduced into the current space through the second current path, thereby reducing the impact on the volumetric energy density of the battery cell caused by the height dimension of the protrusion being too large.

[0010] In some embodiments, along the first direction, the height of the protrusion is H, and 5mm ≥ H ≥ 0.5mm. By H ≥ 0.5mm, the dimension along the first direction of the second current path is made greater than or equal to 0.5mm so that the dimension along the first direction of the second current path satisfies the current flow requirements and allows the discharge within the first current path to flow rapidly into the current space through the second current path; by H ≤ 5mm so that the height of the protrusion is not too large, the space occupied by the protrusion along the first direction inside the housing is reduced, which is advantageous for improving the volumetric energy density of the battery cell. In this way, the current flow requirements of the second current path and the volumetric energy density requirements of the battery cell are considered together.

[0011] In some embodiments, the protrusions along the circumferential direction of the contact portion have opposing first and second portions; the projection of the outer edge of the portion wall along the first direction forms a first circle, and along the first direction, the centrifugal connecting line between the first portion and the first circle is a first connecting line, and the centrifugal connecting line between the second portion and the first circle is a second connecting line, and the angle between the first connecting line and the second connecting line is α, and 15° ≤ α ≤ 60°. By controlling α to 15° to 60°, more protrusions can be installed along the circumferential direction of the contact portion to form more second flow passages, thereby allowing discharges within the first flow passages to flow into the flow space at more locations.

[0012] In some embodiments, a plurality of protrusions are uniformly arranged along the circumferential direction of the contact portion. By allowing a plurality of second flow passages on the contact portion to be uniformly arranged along the circumferential direction of the contact portion, discharges within the second flow passages can be more uniformly introduced into the flow space within the plurality of flow passages, thereby further improving the speed at which discharges within the first flow passages are introduced into the flow space.

[0013] In some embodiments, a flow guide gap is formed between a side wall and a protrusion along the radial direction of the contact portion; the flow guide gap communicates with two adjacent second flow passages. The flow guide gap between the side wall and the protrusion can communicate with two adjacent second flow passages, and when a discharge in a first flow passage flows into a specific second flow passage, the discharge can flow through the flow guide gap to another adjacent second flow passage, thereby allowing the discharge in the first flow passage to flow into the flow space more quickly.

[0014] In some embodiments, the contact portion further comprises a main body portion, the main body portion is installed enclosed by the outer edge of the wall body and protrudes from the wall body along a direction adjacent to the electrode assembly, and along a first direction, the main body portion has a first surface facing the electrode assembly, and the protrusion is installed on the first surface. The main body portion serves to connect the wall body and the protrusion, and the main body portion is installed enclosed by the wall body and protrudes from the wall body along a direction adjacent to the electrode assembly, thereby effectively improving the deformation resistance capability of the end wall.

[0015] In some embodiments, along the first direction, the wall body has a second surface, the second surface 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. In this way, the distance between the second surface and the electrode assembly can be increased, the influence of the electrode assembly on the pressure release mechanism of the wall body can be reduced, and the dimensions of the current guide space along the first direction can be effectively increased.

[0016] In some embodiments, a first groove is provided in the contact portion; along a first direction, the main body portion has a third surface installed 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 in a direction closer to the electrode assembly to form a protrusion protruding from the first surface on one side of the main body portion facing the electrode assembly. By providing a first groove in the contact portion to form a protrusion, the difficulty of molding the protrusion can be effectively reduced, and the weight of the end wall can be effectively reduced.

[0017] In some embodiments, the first groove is a multi-stage groove, and along the first direction, the first groove among the adjacent two-stage grooves that is close to the electrode assembly is installed on the groove bottom surface of the first groove that is far from the electrode assembly. By setting the first groove as a multi-stage groove, the forming force applied to the end wall when forming each end groove is lowered, thereby reducing the risk of damage to the end wall due to excessive forming force when forming the first groove.

[0018] In some embodiments, the protrusion includes a first portion and a second portion, and the multi-stage groove includes a first portion and a second portion; the first portion is recessed from a third surface in a direction close to the electrode assembly to form a first portion protruding from the first surface on one side of the main body facing the electrode assembly, and along the first direction, the first portion has a fourth surface facing the electrode assembly; and the second portion is recessed from the bottom surface of the first portion in a direction close to the electrode assembly to form a second portion protruding from the fourth surface on one side of the first portion facing the electrode assembly. By installing the first portion groove in the main body, the first portion of the protrusion can be formed correspondingly, and by installing the second portion groove in the first portion, the second portion of the protrusion can be formed correspondingly, thereby reducing the difficulty of molding the protrusion.

[0019] In some embodiments, along the radial direction of the contact portion, the first portion has a first side of the inner surface facing the side wall, and the second portion has a second side of the inner surface facing the side wall, the first side is closer to the inner surface of the side wall than the second side, and a flow gap is formed between the second side and the inner surface of the side wall, and the flow gap communicates with two adjacent second flow passages. The flow gap between the second side and the inner surface of the side wall can communicate with two adjacent second flow passages, and when a discharge in the first flow passage flows into a specific second flow passage, the discharge can flow through the flow gap to another adjacent second flow passage, thereby allowing the discharge in the first flow passage to flow into the flow space more quickly.

[0020] In some embodiments, a second groove is installed at a position corresponding to the main body on one side of the end wall facing away from the electrode assembly, and the third surface is the bottom surface of the second groove. By installing the second groove on the end wall and forming the main body correspondingly, the difficulty of molding the main body can be effectively reduced.

[0021] In some embodiments, the end wall and the side wall are installed as powder, and at least a portion of the main body is received within the side wall to form a positional interlock with the side wall. By forming a positional interlock with the side wall, the difficulty of assembling the end wall and the side wall can be effectively reduced.

[0022] In some embodiments, the end wall further includes an edge portion, which is installed surrounding the outer edge of the main body portion, and the edge portion contacts one end of the side wall along the direction in which the end wall faces the electrode assembly. The end wall can be restricted by contacting the edge portion to the side wall and by restricting the end wall to move along the direction in which it is close to the electrode assembly.

[0023] In some embodiments, the wall body and the joint are molded integrally. In this way, the connection strength between the joint and the wall body can be effectively improved.

[0024] In some embodiments, along the first direction, the wall body has a fifth surface, the fifth surface is the surface of the end wall furthest from the electrode assembly, and the pressure release mechanism is closer to the electrode assembly than the fifth surface. When the fifth surface contacts the external member, the distance between the pressure release mechanism and the external member is increased, thereby reducing the influence of the external member on the pressure release mechanism and reducing the risk of premature operation of the pressure release mechanism due to the impact force of the external member.

[0025] In some embodiments, a third groove is installed in the wall body, and the third groove is recessed in a direction close to the electrode assembly from the fifth surface, and a pressure release groove is installed in the bottom wall of the third groove to form a pressure release mechanism at a position where the bottom wall of the third groove corresponds to the pressure release groove. By installing the third groove, which is recessed in a direction facing the electrode assembly from the fifth surface, in the wall body, and installing the pressure release groove in the bottom wall of the third groove to form a corresponding pressure release mechanism, the pressure release mechanism is implemented closer to the electrode assembly than the fifth surface, and the implementation method is simple.

[0026] In some embodiments, a pressure release groove is installed in the wall body to form a pressure release mechanism at a position corresponding to the pressure release groove. By installing a pressure release groove in the wall body and forming an integrated pressure release mechanism accordingly, the molding method of the pressure release mechanism is simple, and the reliability of the pressure release mechanism is higher.

[0027] In some embodiments, the battery cell further comprises a current collector, the current collector is installed between a side wall and an electrode assembly along a first direction, the current collector is electrically connected to the electrode assembly and the side wall, the contact portion is directly contacted to the current collector, and the current collector is directly contacted to a tab. By implementing an electrical connection between the electrode assembly and the side wall through the current collector, the difficulty of the electrical connection between the electrode assembly and the side wall can be reduced.

[0028] In some embodiments, a first central hole is installed in the electrode assembly and a second central hole is installed in the current collector, and the second central hole communicates with the first central hole and the current guide space. When thermal runaway occurs in the battery cell, the discharge generated from the electrode assembly can sequentially pass through the first central hole and the second central hole and flow into the current guide space, thereby further shortening the time from the occurrence of thermal runaway in the battery cell to the start of pressure release of the battery cell through the pressure release mechanism, so that the pressure release mechanism can operate more timely.

[0029] In some embodiments, the housing comprises a case and an end cover; the case has an opening formed at at least one end along a first direction; and the end cover closes the opening; wherein at least one end cover is a single wall and the case comprises a side wall. The at least one end cover is a single wall, which allows a pressure relief mechanism to be installed in the at least one end cover, thereby reducing the difficulty of forming or mounting the pressure relief mechanism, and allows a second flow path to be installed in the end cover, thereby reducing the difficulty of forming the second flow path.

[0030] In some embodiments, the battery cell is a cylindrical battery cell.

[0031] According to a second aspect, an embodiment of the present application provides a battery comprising a battery cell provided in any one embodiment according to a first aspect.

[0032] According to a third aspect, an embodiment of the present application further provides an electric device comprising a battery cell provided in any one embodiment according to a first aspect, wherein the battery cell is used to provide electric energy to the electric device. Brief explanation of the drawing

[0033] In order to explain the technical solution of the embodiments of the present application more clearly, the drawings to be used in the embodiments are briefly introduced below. The following drawings represent only some embodiments of the present application and should not be considered as limiting the scope. It should be understood by those skilled in the art that other related drawings may be obtained from these drawings under the premise of not striving to create an inventive step. FIG. 1 is a schematic diagram of the structure of a vehicle provided in some embodiments of the present application. FIG. 2 is an exploded view of a battery provided in some embodiments of the present application. FIG. 3 is an exploded view of a battery cell provided in some embodiments of the present application. Figure 4 is a cross-sectional view of the battery cell shown in Figure 3. Figure 5 is a local enlarged view of the battery cell shown in Figure 4. Figure 6 is a schematic diagram of the structure of the short wall shown in Figure 5. Figure 7 is a cross-sectional view of the AA wall shown in Figure 6. Figure 8 is a drawing of the B direction of the short wall shown in Figure 7. FIG. 9 is a local enlarged view of a battery cell provided in some other embodiments of the present application. Figure 10 is a local enlarged view of part C in Figure 9. Figure 11 is a schematic diagram of the structure of the short wall shown in Figure 9. Fig. 12 is a DD cross-sectional view of the short wall shown in Fig. 11. Specific details for implementing the invention

[0034] In order to make the purpose, technical solution, and advantages of the embodiments of the present application clearer, the technical solution of the embodiments of the present application is described below in conjunction with the drawings of the embodiments of the present application in a clear and complete manner. It is obvious that the described embodiments are only some, not all, of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without striving to create an inventive step fall within the scope of protection of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used in this application shall have the same meaning as commonly understood by those skilled in the art to which this application pertains. Terms used in the specification claimed in this application are intended merely to describe specific embodiments and are not intended to limit this application. The terms “comprising” and “comprising,” and any variations thereof, in the specification, claims, and brief description of the drawings of this application are intended to cover non-exclusive inclusions. Terms such as “first,” “second,” etc., in the specification and claims of this application or in the drawings are used to distinguish different objects, rather than to describe a specific order or priority relationship.

[0036] The term “Examples” as used in this application means that specific features, structures, or characteristics described in conjunction with the Examples may be included in at least one Example of this application. The appearance of this phrase in various places within the specification does not necessarily refer to the same Example, nor are they independent or alternative Examples mutually exclusive from other Examples.

[0037] In the description of this application, unless otherwise explicitly defined and limited, the terms “mounting” and “connection” should be understood in a broad sense, for example, as fixed connections, detachable connections, or integral connections; and it should be explained that a person skilled in the art may understand the specific meaning of the terms described above in this application depending on the specific circumstances.

[0038] In this application, the term “and / or” merely describes an association describing related objects and indicates that there may be three types of relationships; for example, A and / or B may represent three cases where A exists alone, A and B exist simultaneously, or B exists alone. Additionally, in this application, the letter “ / ” generally indicates that the related objects before and after it are in an “or” relationship.

[0039] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of simplification, detailed descriptions of the same components in other embodiments are omitted. It should be understood that the dimensions, such as thickness, length, and width of the various components of the embodiments of this application illustrated in the drawings, and the overall thickness, length, and width of the integrated device, are merely illustrative descriptions and do not constitute any limitations to this application.

[0040] The term “plural” as used in this application refers to two or more (including two).

[0041] In an embodiment of the present application, the battery cell may be a secondary battery, and the secondary battery refers to a battery cell that can be continuously used by activating the active material through a method of charging the battery cell after it has been discharged.

[0042] Battery cells include, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium-metal batteries, sodium-metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc.

[0043] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell, active ions (e.g., lithium ions) are reciprocally inserted and removed between the positive and negative electrodes. The separator is installed between the positive and negative electrodes to reduce the risk of a short circuit between them while allowing active ions to pass through.

[0044] In some embodiments, the anode may be an anode sheet, and the anode sheet may include an anode current collector and an anode active material installed on at least one surface of the anode current collector.

[0045] As an example, the positive current collector has two opposing surfaces in its own thickness direction, and the positive active material is installed on one or both of the two opposing surfaces of the positive current collector.

[0046] As an example, the positive current collector may use a metal foil or a composite current collector. For example, as a metal foil, surface silver-plated aluminum, surface silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. may be used. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0047] As an example, the positive electrode active material may comprise at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound thereof. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. Such positive electrode active materials may be used alone or in combination of two or more. Here, examples of lithium-containing phosphates include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (also called LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of lithium transition metal oxides include lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (NCM 333 Also known as), LiNi 0.5 Co 0.2 Mn 0.3 O2 (NCM 523 Also known as), LiNi 0.5 Co 0.25 Mn 0.25 O2 (NCM 211 Also known as), LiNi 0.6 Co 0.2 Mn 0.2 O2 (NCM 622 Also known as), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM 811 Also known as), lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05It may include at least one of O2) and their modified compounds, but is not limited thereto.

[0048] In some embodiments, the anode may use a foamed metal. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. When a foamed metal is used as the anode, the anode active material may not be installed on the surface of the foamed metal, or, of course, the anode active material may be installed. As an example, a lithium raw material, potassium metal, or sodium metal may be filled or / and deposited within the foamed metal, and the lithium raw material is a lithium metal and / or a lithium-rich material.

[0049] In some embodiments, the cathode may be a cathode sheet, and the cathode sheet may include a cathode current collector.

[0050] As an example, the negative current collector may use a metal foil, foamed metal, or composite current collector. For example, as the metal foil, silver-surfaced aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc., may be used. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. The composite current collector may include a polymer material substrate and a metal layer. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material substrate (e.g., a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0051] As an example, the cathode sheet may include a cathode current collector and a cathode active material installed on at least one surface of the cathode current collector.

[0052] As an example, the cathode current collector has two opposing surfaces in its own thickness direction, and the cathode active material is installed on either or both of the two opposing surfaces of the cathode current collector.

[0053] For example, the negative electrode active material may be a negative electrode active material for a battery cell known in the art. As an example, the negative electrode active material may include at least one of materials such as synthetic graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titaniumate. The silicon-based material may be selected from at least one of silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of tin, tin oxide compounds, and tin alloys. However, the present 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. Such negative electrode active materials may be used individually or in combination of two or more types.

[0054] In some embodiments, the material of the positive current collector may be aluminum, and the material of the negative current collector may be copper.

[0055] In some embodiments, the separation member is a separation membrane. Any known porous structure separation membrane with excellent chemical and mechanical stability may be selected as the separation membrane.

[0056] 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 thin film or a multilayer composite thin film. If the separator is a multilayer composite thin film, the material of each layer may be the same or different. The separating member may be a separate member located between the positive and negative electrodes, or it may be attached to the surface of the positive and negative electrodes.

[0057] In some embodiments, the separating member is a solid electrolyte. The solid electrolyte is installed between the anode and the cathode and serves to transport ions and separate the anode and the cathode.

[0058] In some embodiments, the battery cell further comprises an electrolyte, and the electrolyte serves to conduct ions between the positive electrode and the negative electrode. The electrolyte may be in a liquid state, a gel state, or a solid state. Here, the liquid electrolyte comprises an electrolyte salt and a solvent.

[0059] In some embodiments, the electrolyte salt may comprise at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bistrifluoromethanesulfonylimide, lithium trifluoromethanesulfonylimide, lithium difluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalate)borate, lithium bis(oxalate)borate, lithium difluoro(oxalate)phosphate, and lithium tetrafluoro(oxalate)phosphate.

[0060] In some embodiments, the solvent may comprise at least one of ethylene carbonate, propylene carbonate, ethylmethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, tetramethylene sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be selected from ether solvents. The ether-based solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0061] Here, the gel electrolyte comprises a framework network in which a polymer incorporated into an ionic liquid-lithium salt serves as the electrolyte.

[0062] Here, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0063] As an example, polymeric solid electrolytes may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, homoionic polymer, polyionic liquid-lithium salt, cellulose, etc.

[0064] As an example, inorganic solid electrolytes may include one or more of oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superion conductor (lithium germanium phosphorus, sulfur silver germanium ore), amorphous sulfide) and halide solid electrolytes, nitride solid electrolytes and hydride solid electrolytes.

[0065] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte as a filler to a polymeric solid electrolyte.

[0066] In some embodiments, the electrode assembly is a wound structure. The positive electrode sheet and the negative electrode sheet are wound in a wound structure.

[0067] In some embodiments, the electrode assembly has a laminated structure.

[0068] As an example, multiple anode sheets and multiple cathode sheets can be installed, and multiple anode sheets and multiple cathode sheets are installed by stacking them alternately.

[0069] As an example, multiple anode sheets can be installed, and cathode sheets are stacked to form a stacked fragment installed in multiple layers, and one anode sheet is clamped between adjacent stacked fragments.

[0070] As an example, both the positive and negative sheets are laminated to form a laminated section installed with multiple layers.

[0071] As an example, multiple separating members may be installed, each installed between any adjacent positive or negative sheet.

[0072] As an example, the separating member can be installed continuously and is installed between any adjacent anode or cathode sheet in a stacked or wound manner.

[0073] In some embodiments, the shape of the electrode assembly may be cylindrical, flat, or polygonal, etc.

[0074] In some embodiments, a tap is installed in the electrode assembly and the tap can conduct current from the electrode assembly. The tap includes a positive tap and a negative tap.

[0075] In some embodiments, the battery cell may include a housing. The housing is used to seal and package components such as an electrode assembly and an electrolyte. The housing may be a steel case, an aluminum case, a plastic case (e.g., polypropylene), a composite metal case (e.g., a copper-aluminum composite housing), or an aluminum-plastic film, etc.

[0076] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft pack battery cell, or a battery cell of other shapes, wherein the prismatic battery cell includes a rectangular battery cell, a blade-shaped battery cell, and a polygonal prismatic battery cell, and the polygonal prismatic battery cell is, for example, a hexagonal prismatic battery cell.

[0077] The battery mentioned in the embodiments of the present application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0078] In some embodiments, the battery may be a battery module, and when there are multiple battery cells, multiple battery cells are arranged and fixed to form a single battery module.

[0079] In some embodiments, the battery may be a battery pack, the battery pack includes a box body and a battery cell, and the battery cell or battery module is accommodated in the box body.

[0080] In some embodiments, the box body may be used as part of the chassis structure of a vehicle. For example, a part of the box body may be at least part of the vehicle floor, or a part of the box body may be at least part of the vehicle's transverse and longitudinal beams.

[0081] In some embodiments, the battery may be an energy storage device. The energy storage device includes an energy storage container, an energy storage electric cabinet, etc.

[0082] In some embodiments, to improve the reliability of the battery cell, a pressure release mechanism may generally be installed on the end wall of the battery cell housing, and the pressure inside the battery cell may be released through the pressure release mechanism when the battery cell undergoes thermal runaway.

[0083] A pressure release mechanism refers to a component or element that operates to release internal pressure when the internal pressure of a battery cell reaches a preset threshold. The design of this threshold varies according to design requirements. The threshold may vary depending on one or more materials among the positive sheet, negative sheet, electrolyte, and separator in the battery cell.

[0084] The term "operation" as used in this application means that the pressure relief mechanism is activated to an operating state or a certain state to release the internal pressure of the battery cell. The operation caused by the pressure relief mechanism may include, but is not limited to, the rupture, crushing, cracking, or opening of at least a part of the pressure relief mechanism. When the pressure relief structure operates, high-temperature, high-pressure material inside the battery cell is discharged from the operating part to the outside as an exhaust. In this way, the battery cell is allowed to release pressure at a controllable pressure, thereby potentially avoiding more serious accidents.

[0085] The effluents from the battery cell mentioned in the embodiments of the present application include, but are not limited to, electrolyte, dissolved or fragmented positive and negative electrode sheets, fragments of the separator, high-temperature and high-pressure gas generated by the reaction, flame, etc.

[0086] In a conventional battery cell, a contact portion protruding in a direction adjacent to the electrode assembly can be formed on the end wall where the pressure relief mechanism is installed, and the purpose of reducing the movement of the electrode assembly within the housing is achieved by making direct or indirect contact with the tab of the electrode assembly through this contact portion. However, since the contact portion makes direct or indirect contact with the tab of the electrode assembly, when thermal runaway occurs in the battery cell, it is difficult for the discharge between the electrode assembly and the side wall of the housing to reach the end wall area where the pressure relief mechanism is installed. Consequently, the pressure relief mechanism fails to operate in a timely manner, creating a risk of battery cell explosion or ignition and affecting the reliability of the battery cell.

[0087] To address the problem of low reliability of the battery cell, an embodiment of the present application provides a battery cell, wherein the end wall of the housing comprises a wall body and a contact portion, a pressure relief mechanism is installed in the wall body, and the contact portion is installed enclosed by the outer edge of the wall body. The contact portion protrudes from the wall body along a direction adjacent to the electrode assembly and contacts the electrode assembly directly or indirectly, and a first current passage is formed between the electrode assembly and the side wall of the housing. The contact portion and the wall body jointly define a current space, and a second current passage is installed in the contact portion, and the second current passage communicates the current space and the first current passage.

[0088] In such a battery cell, a second current passage is installed at the contact portion, and the second current passage connects the current space and the first current passage. When thermal runaway occurs in the battery cell, the discharge generated from the electrode assembly flows into the first current passage, and then the discharge can rapidly flow into the current space through the second current passage on the contact portion. This rapidly increases the air pressure within the current space, quickly reaching the burst pressure of the pressure release mechanism. This shortens the time from the occurrence of thermal runaway in the battery cell to the start of pressure release from the battery cell through the pressure release mechanism, thereby enabling the pressure release mechanism to operate in a timely manner, reducing the risk of battery cell explosion and ignition, and effectively improving the reliability of the battery cell.

[0089] The battery cell described in the embodiments of the present application is applied to a battery and an electrical device using the battery cell.

[0090] Electric devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and power tools. Vehicles may be fuel vehicles, natural gas vehicles, or new energy vehicles, and new energy vehicles may be pure electric vehicles, hybrid vehicles, or range-extended vehicles; spacecraft include aircraft, rockets, space shuttles, and spacecraft; electric toys include stationary or mobile electric toys such as game consoles, electric car toys, electric ship toys, and electric airplane toys; and 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 electric drills, concrete vibrators, and electric planers.

[0091] For convenience of explanation, the following embodiments are described by using an electric device as a vehicle.

[0092] Referring to FIG. 1, FIG. 1 is a schematic diagram of the structure of a vehicle (1000) provided in some embodiment of the present application. A battery (100) is installed inside the vehicle (1000), and the battery (100) may be installed in the bottom part, the head part, or the tail part of the vehicle (1000). The battery (100) may be used to supply power to the vehicle (1000), and, for example, the battery (100) may be used as the working power source of the vehicle (1000).

[0093] The vehicle (1000) may also include a controller (200) and a motor (300), and the controller (200) is used to control the battery (100) to supply power to the motor (300), for example, for power required for operation during starting, navigation, and driving of the vehicle (1000).

[0094] In some embodiments of the present application, the battery (100) can be used not only as an operating power source for the vehicle (1000), but also as a driving power source for the vehicle (1000), and provides driving power to the vehicle (1000) by replacing or partially replacing fuel or natural gas.

[0095] Referring to FIG. 2, FIG. 2 is an exploded view of a battery (100) provided in some embodiment of the present application. The battery (100) includes a battery cell (10) and a box body (20), and the battery cell (10) is accommodated within the box body (20).

[0096] Here, the box body (20) is a member that accommodates the battery cell (10), the box body (20) provides a receiving space for the battery cell (10), and the box body (20) can use various structures. In some embodiments, the box body (20) may include a first box body (201) and a second box body (202), and the first box body (201) and the second box body (202) cover each other to define a receiving space for accommodating the battery cell (10). The first box body (201) and the second box body (202) may have various shapes, such as a rectangular prism, a cylinder, etc. The first box body (201) may be a hollow structure with one side open, and the second box body (202) may also be a hollow structure with one side open, and the open side of the second box body (202) is covered by the open side of the first box body (201), that is, forms a box body (20) having a receiving space. The first box body (201) may be a hollow structure with one side open, and the second box body (202) may be a plate-like structure, and the second box body (202) is covered by the open side of the first box body (201), that is, forms a box body (20) having a receiving space. The first box body (201) and the second box body (202) may be sealed through a sealing element, and the sealing element may be a sealing ring, a sealing adhesive, etc.

[0097] In the battery (100), the battery cell (10) may be one or multiple. If there are multiple battery cells (10), the multiple battery cells (10) may be connected in series, parallel, or mixed, and a mixed connection refers to the multiple battery cells (10) having both series and parallel connections. The multiple battery cells (10) may first form a battery module by connecting them in series, parallel, or mixed, and then the multiple battery modules may be connected again in series, parallel, or mixed to form a whole and accommodated within a box (20). Alternatively, all battery cells (10) may be directly connected in series, parallel, or mixed, and then the whole composed of all battery cells (10) may be accommodated within a box (20).

[0098] Referring to FIGS. 3 and FIGS. 4, FIG. 3 is an exploded view of a battery cell (10) provided in some embodiment of the present application; FIG. 4 is a cross-sectional view of the battery cell (10) shown in FIG. 3. The battery cell (10) may include a housing (1) and an electrode assembly (2), and the electrode assembly (2) is accommodated within the housing (1).

[0099] In some embodiments, the housing (1) may include a case (11) and an end cover (12), the case (11) has an opening, and the end cover (12) closes the opening of the case (11).

[0100] The case (11) is a member for accommodating the electrode assembly (2), and the case (11) may be a hollow structure forming an opening at one end, or the case (11) may be a hollow structure forming openings at both opposing ends. The case (11) may have various shapes, such as a cylindrical shape or a prismatic shape. The material of the case (11) may be of various types, such as copper, iron, aluminum, steel, or aluminum alloy.

[0101] The end cover (12) is a component that isolates the internal environment of the battery cell (10) from the external environment by closing the opening of the case (11). The end cover (12) and the case (11) jointly define a receiving space for accommodating the electrode assembly (2), electrolyte, and other components. The end cover (12) may be connected to the case (11) by means of welding or rolling to close the opening of the case (11). The shape of the end cover (12) may match the shape of the housing (1); for example, the case (11) may have a rectangular parallepiped structure and the end cover (12) may have a rectangular plate structure that matches the housing (1); and for example, the case (11) may have a cylindrical structure and the end cover (12) may have a circular plate structure that matches the case (11). The material of the end cover (12) can be of various types, such as copper, iron, aluminum, steel, aluminum alloy, etc., and the material of the end cover (12) and the case (11) may be the same or different.

[0102] In an embodiment where the case (11) has an opening formed at one end, the end cover (12) can be installed as a single unit in correspondence. In an embodiment where the case (11) has openings formed at both opposing ends, two end covers (12) can be installed in correspondence, and the two end covers (12) each close the two openings of the case (11), and the two end covers (12) and the case (11) jointly define the receiving space.

[0103] In some embodiments, the battery cell (10) may also include an electrode terminal (3) installed on the housing (1), and the electrode terminal (3) is used to be electrically connected to a tab (21) of the electrode assembly (2) to input or output electrical energy of the battery cell (10). The electrode terminal (3) may be installed on the case (11) of the housing (1) and may also be installed on the end cover (12) of the housing (1). The electrode terminal (3) and the tab (21) may be directly connected, for example, the electrode terminal (3) and the tab (21) are welded. The electrode terminal (3) and the tab (21) may also be indirectly connected, for example, the electrode terminal (3) and the tab (21) are indirectly connected through a current collector (4). The current collector (4) may be a metal conductor such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0104] As an example, in the embodiment illustrated in FIGS. 3 and 4, the battery cell (10) is a cylindrical battery cell, the case (11) has an opening formed only at one end, and there is one end cover (12) which closes the opening of the case (11), and an electrode terminal (3) is installed on the wall of the case (11) facing the end cover (12). Both opposing ends of the electrode assembly (2) have tabs (21), the tab (21) at one end of the electrode assembly (2) is a positive tab, and the tab (21) at the other end is a negative tab, and the electrode terminal (3) is electrically connected to the positive tab through one current collector (4), and the end cover (12) is electrically connected to the negative tab through another current collector (4).

[0105] Referring to FIGS. 5 and FIGS. 6, FIG. 5 is a local enlarged view of the battery cell (10) shown in FIG. 4; FIG. 6 is a schematic diagram of the structure of the end wall (13) shown in FIG. 5. An embodiment of the present application provides a battery cell (10), the battery cell (10) comprises a housing (1) and an electrode assembly (2). The housing (1) comprises an end wall (13) and a side wall (14), the end wall (13) is installed at one end along a first direction (X) of the side wall (14), and the side wall (14) is installed surrounding the end wall (13). The electrode assembly (2) is accommodated within the housing (1), and one end of the electrode assembly (2) facing the end wall (13) has a tab (21), and a first flow path (6) is formed between the tab (21) and the side wall (14). The end wall (13) includes a wall body (131) and a contact portion (132), a pressure release mechanism (5) is installed in the wall body (131), and the contact portion (132) is installed surrounding the outer edge of the wall body (131). Along the first direction (X), the contact portion (132) protrudes from the wall body (131) along a direction adjacent to the electrode assembly (2) and contacts the tab (21) directly or indirectly. The contact portion (132) and the wall body (131) jointly define a current-conducting space (133), and a second current-conducting passage (1321) is installed in the contact portion (132), and the second current-conducting passage (1321) connects the current-conducting space (133) with the first current-conducting passage (6).

[0106] In an embodiment where the case (11) forms an opening at only one end, the end cover (12) may be made into a short wall (13) and the side wall (14) may be made into part of the case (11); or the wall portion of the case (11) facing the end cover (12) may be made into a short wall (13), and the side wall (14) and the short wall (13) may be formed integrally to form the case (11). In an embodiment where the case (11) forms openings at both opposing ends, at least one of the two end covers (12) may be made into a short wall (13) and the side wall (14) may be made into the case (11).

[0107] The side wall (14) may be cylindrical, so that the battery cell (10) is a cylindrical battery cell; the side wall (14) may be rectangular, so that the battery cell (10) is a rectangular battery cell (10) or a blade-shaped battery cell (10). The side wall (14) and the end wall (13) may be formed integrally, and the side wall (14) and the end wall (13) constitute a case (11), and one end of the side wall (14) extending away from the end wall (13) along the first direction (X) forms an opening of the case (11); the side wall (14) and the end wall (13) may be installed as powder, and the end wall (13) is an end cover (12), and one end of the side wall (14) extending close to the end wall (13) along the first direction (X) forms an opening of the case (11). In an embodiment where the side wall (14) and the end wall (13) are installed as powder, the end wall (13) and the side wall (14) can be connected by means such as welding, bonding, or rolling.

[0108] The electrode assembly (2) may additionally include a main body portion, and a tap (21) is installed at at least one end along the first direction (X) of the main body portion (22). The first flow path (6) may be a gap formed between the outer surface of the tap (21) and the inner surface (141) of the side wall (14). After the electrode assembly (2) is assembled in the housing (1), a gap communicating with the first flow path (6) may be formed between the outer surface of the main body portion (22) and the inner surface (141) of the side wall (14), and discharges generated due to thermal runaway of the electrode assembly (2) may flow into the first flow path (6) through this gap. Of course, if an insulating film is coated on the outer surface of the main body portion (22), a gap communicating with the first flow path (6) may be formed between the outer surface of the insulating film and the inner surface (141) of the side wall (14). Here, the inner surface (141) of the side wall (14) is the surface of the side wall (14) facing the electrode assembly (2), and the inner surface (141) can be extended in one full circle along the circumferential direction of the opening of the case (11). It can be understood that if the side wall (14) is cylindrical, the inner surface (141) of the side wall (14) is cylindrical; and if the side wall (14) is rectangular, the inner surface (141) of the side wall (14) is rectangular.

[0109] The wall body (131) and the contact portion (132) may be integrally molded and may be installed and connected as a powder. The pressure release mechanism (5) may be a pressure release member installed as a powder with the wall body (131), and the pressure release member may be mounted on the wall body (131), and the pressure release member may be an explosion-proof sheet, a pressure release valve, etc.; the pressure release mechanism (5) may be a structure integrally molded with the wall body (131), and for example, the pressure release mechanism (5) is a weak part formed in the wall body (131). The weak part may be formed by installing a groove in the wall body (131), or the weak part may be formed by performing local heat treatment on the wall body (131) to weaken the strength of this local area.

[0110] The contact portion (132) may be an annular structure that surrounds the outer edge of the wall body (131), and the annular structure may be a circular ring structure, a rectangular ring structure, etc. After the contact portion (132) is contacted directly or indirectly to the tab (21) of the electrode assembly (2), the contact portion (132) and the electrode assembly (2) may be electrically connected or insulatedly connected, and the tab (21) may be a positive tab or a negative tab. When the contact portion (132) is contacted directly to the tab (21) of the electrode assembly (2), the contact portion (132) is made to come into direct contact with the tab (21) of the electrode assembly (2), for example, the contact portion (132) is contacted directly to the tab (21) of the end of the electrode assembly (2) to realize an electrical connection between the end wall (13) and the electrode assembly (2); When the contact portion (132) is indirectly contacted to the tab (21) of the electrode assembly (2), an intermediate member is installed between the contact portion (132) and the electrode assembly (2), and this intermediate member may be an insulating member or a conductive member. For example, when the current collecting member (4) is used as the intermediate member, the contact portion (132) is indirectly contacted to the tab (21) at the end of the electrode assembly (2) through the current collecting member (4), thereby enabling an electrical connection between the end wall (13) and the electrode assembly (2).

[0111] A current-conducting space (133), jointly defined by a wall body (131) and a contact portion (132), corresponds to a pressure release mechanism (5), and after the pressure release mechanism (5) is activated, the discharge located within the current-conducting space (133) can be discharged to the outside of the battery cell (10) through the pressure release mechanism (5). Along the first direction (X), an opening is formed in the current-conducting space (133) at one end of the contact portion (132) adjacent to the electrode assembly (2), and after the contact portion (132) is directly or indirectly contacted to the electrode assembly (2), the opening is covered. When the contact portion (132) is directly contacted to the electrode assembly (2), the opening of the current-conducting space (133) is covered by the electrode assembly (2); When the contact portion (132) is indirectly contacted to the electrode assembly (2) through the intermediate member, it can be understood that the opening of the current-conducting space (133) is covered by the intermediate member.

[0112] The second flow path (1321) on the joint portion (132) may be one or multiple. If there are multiple second flow paths (1321), the multiple flow paths may be uniformly distributed along the circumferential direction (Y) of the joint portion, or they may be non-uniformly distributed along the circumferential direction (Y) of the joint portion. Here, the circumferential direction (Y) of the joint portion may be the circumferential direction of a circle surrounding a centerline extending along the first direction (X).

[0113] The second flow passage (1321) may be a through hole that penetrates the contact portion (132) along the radial direction (Z) of the contact portion, or a notch groove that penetrates the contact portion (132) along the radial direction (Z) of the contact portion and extends to one end of the contact portion (132) adjacent to the electrode assembly (2) along the first direction (X).

[0114] In an embodiment of the present application, the contact portion (132) of the end wall (13) is in direct or indirect contact with the tab (21) of the electrode assembly (2), and the contact portion (132) can restrict the electrode assembly (2) and reduce the risk of the electrode assembly (2) moving along the first direction (X) within the housing (1). A second flow path (1321) is installed in the contact portion (132) and the second flow path (1321) is connected to the flow space (133) and the first flow path (6). When thermal runaway occurs in the battery cell (10), the discharge generated from the electrode assembly (2) flows into the first flow path (6), and then the discharge can rapidly flow into the flow space (133) through the second flow path (1321) on the contact portion (132), thereby rapidly increasing the air pressure within the flow space (133) and rapidly reaching the burst pressure of the pressure release mechanism (5). This shortens the time from the occurrence of thermal runaway in the battery cell (10) until the pressure release of the battery cell (10) through the pressure release mechanism (5) begins, thereby allowing the pressure release mechanism (5) to operate in a timely manner, reducing the risk of explosion and ignition of the battery cell (10) and effectively improving the reliability of the battery cell (10).

[0115] In some embodiments, referring to FIG. 6, a plurality of second flow passages (1321) are installed in the joint portion (132), and the plurality of second flow passages (1321) are installed spaced apart along the circumferential direction (Y) of the joint portion.

[0116] The second flow passage (1321) on the contact portion (132) may be 2, 3, 4, 5, 6 or more.

[0117] As an example, a plurality of second flow passages (1321) on the joint portion (132) are uniformly distributed along the circumferential direction (Y) of the joint portion, that is, the angle between each of two adjacent second flow passages (1321) along the circumferential direction (Y) of the joint portion is the same. Taking the case where there are four second flow passages (1321) on the joint portion (132) as an example, each of two adjacent second flow passages (1321) along the circumferential direction (Y) of the joint portion is 90°.

[0118] In this embodiment, a plurality of second flow passages (1321) are installed in the contact portion (132) at spaced intervals along the circumferential direction (Y) of the contact portion, so that the discharge from the first flow passage (6) can flow into the flow space (133) from the plurality of second flow passages (1321) located at different positions, thereby increasing the speed at which the discharge from the first flow passage (6) flows into the flow space (133) and further shortening the time from the occurrence of thermal runaway of the battery cell (10) until the start of pressure release of the battery cell (10) through the pressure release mechanism (5).

[0119] In some embodiments, continuing to refer to FIG. 6, along the first direction (X), the contact portion (132) has a contact surface (1322), the contact surface (1322) is the surface of the contact portion (132) closest to the electrode assembly (2), and the second flow path (1321) is a notch groove that penetrates the contact portion along the radial direction (Z) of the contact portion (132) and extends to the contact surface (1322) along the first direction (X).

[0120] The contact surface (1322) is the surface of the contact 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 contact portion is perpendicular to the first direction (X). A notch groove penetrates the contact portion (132) along the radial direction of the contact portion, so that the second current passage (1321) communicates with the current space (133) and the first current passage (6). The notch groove extends along the first direction (X) to the contact surface (1322), and the notch groove can be formed by being sunken from the contact surface (1322) along the direction opposite to the electrode assembly (2), and the notch groove forms a groove in the contact surface (1322).

[0121] In an embodiment where the contact portion (132) is directly contacted to the tab (21) of the electrode assembly (2), the contact surface (1322) is in direct contact with the tab (21) of the end of the electrode assembly (2), and the tab (21) can cover the groove of the notch groove formed on the contact surface (1322); in an embodiment where the contact portion (132) is indirectly contacted to the tab (21) of the electrode assembly (2) through an intermediate member, the contact surface (1322) is in direct contact with the intermediate member, and the intermediate member can cover the groove of the notch groove formed on the contact surface (1322).

[0122] In this embodiment, the second flow passage (1321) is a notch groove that penetrates the contact portion (132) along the radial direction (Z) of the contact portion (132) and extends to the contact surface (1322) along the first direction (X). This is advantageous in that, on one hand, it can reduce the difficulty of forming the second flow passage (1321), and on the other hand, it increases the dimensions of the second flow passage (1321) along the first direction (X), thereby improving the speed at which the discharge within the first flow passage (6) flows into the flow space (133) through the second flow passage (1321).

[0123] In some embodiments, continuing to refer to FIG. 5 and FIG. 6, the contact portion (132) includes a plurality of protrusions (1323), the plurality of protrusions (1323) contact directly or indirectly with the tab (21) of the electrode assembly (2), and a second flow path (1321) is formed between two adjacent protrusions (1323) along the circumferential direction (Y) of the contact portion.

[0124] The protrusions (1323) of the joint portion (132) may be 2, 3, 4, 5 or more. The number of the second flow passage (1321) and the protrusions (1323) are the same, and the second flow passage (1321) and the protrusions (1323) are installed alternately along the circumferential direction (Y) of the joint portion. As an example, the multiple protrusions (1323) of the joint portion (132) are uniformly distributed along the circumferential direction (Y) of the joint portion, that is, the angle between each pair of adjacent protrusions (1323) along the circumferential direction (Y) of the joint portion is the same. Taking the case where there are 4 protrusions (1323) of the joint portion (132) as an example, the angle between each pair of adjacent protrusions (1323) along the circumferential direction (Y) of the joint portion is 90°.

[0125] The protrusion (1323) is located within the side wall (14), and the protrusion (1323) may come into contact with the inner surface of the side wall (14) and may have a gap between the two.

[0126] By forming a second flow passage (1321) between two adjacent protrusions (1323), the discharge from the first flow passage (6) can flow into the flow space (133) from multiple second flow passages (1321) located at different positions, thereby improving the speed at which the discharge from the first flow passage (6) flows into the flow space (133). In addition, the second flow passage (1321) having this structure is a notch groove formed in the contact portion (132), which not only reduces the difficulty of forming the second flow passage (1321) but is also advantageous for increasing the dimensions along the first direction (X) of the second flow passage (1321).

[0127] In some embodiments, referring to FIG. 7, FIG. 7 is a cross-sectional view AA of the end wall (13) shown in FIG. 6. The protrusion (1323) has a contact surface (1322), and the contact surface (1322) is used to make an electrical connection between the end wall (13) and the electrode assembly (2) by making contact directly or indirectly with the tap (21). Along the first direction (X), the height of the protrusion (1323) is H; along the radial direction (Z) of the contact, the width of the contact surface (1322) is W; and 0.1W ≤ H ≤ 0.5W.

[0128] In an embodiment where the contact surface (1322) is in direct contact with the tab (21) of the electrode assembly (2), the contact surface (1322) is in direct contact with the tab (21) of the end of the electrode assembly (2), and an electrical connection between the end wall (13) and the electrode assembly (2) can be realized; in an embodiment where the contact surface (1322) is indirectly contacted with the tab (21) of the electrode assembly (2) through an intermediate member, the contact surface (1322) is in direct contact with the intermediate member, the intermediate member is a conductive member, and the end wall (13) and the tab (21) of the electrode assembly (2) can be electrically connected through the intermediate member.

[0129] The height of the protrusion (1323) is equal to the depth of the notch groove (second flow passage (1321)).

[0130] It can be understood that 0.1≤H / W≤0.5, and H / W can be any one point value among 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 or a range value between any two.

[0131] By directly or indirectly contacting the contact surface (1322) with the tab (21) of the electrode assembly (2), an electrical connection between the end wall (13) and the electrode assembly (2) can be realized, and to realize a stable current between the end wall (13) and the electrode assembly (2), the contact surface (1322) generally has a constant width, and thus, the height of the protrusion (1323) is controlled within the range of 0.1W to 0.5W so that the dimensions along the first direction (X) of the second current passage (1321) can satisfy the current flow requirements, and the discharge within the first current passage (6) can be rapidly introduced into the current space (133) through the second current passage (1321), thereby reducing the impact on the volume energy density of the battery cell (10) by preventing the height dimension of the protrusion (1323) from being too large.

[0132] In some embodiments, along the first direction (X), the height of the protrusion (1323) is H, and 5mm≥H≥0.5mm.

[0133] H can be any one point value of 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, or a range value between any two.

[0134] In this embodiment, H≥0.5mm, so that the dimension along the first direction (X) of the second current passage (1321) is greater than or equal to 0.5mm, thereby satisfying the current flow requirements, and allowing the discharge within the first current passage (6) to flow rapidly into the current space (133) through the second current passage (1321); and H≤5mm, so that the height of the protrusion (1323) is not too large, thereby reducing the space occupied by the protrusion (1323) along the first direction (X) inside the housing (1), which is advantageous for improving the volumetric energy density of the battery cell (10). In this way, the current flow requirements of the second current passage (1321) and the volumetric energy density requirements of the battery cell (10) are considered together.

[0135] In some embodiments, referring to FIG. 8, FIG. 8 is a drawing of the B direction of the end wall (13) shown in FIG. 7. Along the circumferential direction (Y) of the joint, the protrusion (1323) has opposing first end (13231) and second end (13232). The projection of the outer edge of the end wall (13) along the first direction (X) forms a first circle (Q), and along the first direction (X), the centrifugal connecting line between the first end (13231) and the first circle (Q) is a first connecting line (U), and the centrifugal connecting line between the second end (13232) and the first circle (Q) is a second connecting line (V), and the angle between the first connecting line (U) and the second connecting line (V) is α, and 15° ≤ α ≤ 60°.

[0136] The angle between the first connecting line (U) and the second connecting line (V) is the centrifugal angle of the protrusion (1323), and both the first connecting line (U) and the second connecting line (V) are straight lines.

[0137] α can take any one point value of 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, or a range value between any two.

[0138] By controlling α to 15° to 60°, more protrusions (1323) can be installed along the circumferential direction (Y) of the contact part to form more second flow passages (1321), allowing the discharge from the first flow passage (6) to flow into the flow space (133) at more locations.

[0139] In some embodiments, referring to FIG. 8, a plurality of protrusions (1323) are uniformly arranged along the circumferential direction (Y) of the contact portion.

[0140] It can be understood that the angle between each of two adjacent protrusions (1323) along the circumferential direction (Y) of the contact portion is the same, and the angle between each of two adjacent protrusions (1323) is β=360° / N, where N is the number of protrusions (1323). In the embodiment illustrated in FIG. 8, N=4 and β=90°.

[0141] In this embodiment, a plurality of protrusions (1323) are uniformly arranged along the circumferential direction (Y) of the contact portion, so that a plurality of second flow passages (1321) on the contact portion (132) can be uniformly arranged along the circumferential direction (Y) of the contact portion, thereby allowing the discharge within the second flow passages (1321) to flow more uniformly into the flow space (133) within the plurality of flow passages, and further improving the speed at which the discharge within the first flow passage (6) flows into the flow space (133).

[0142] In some embodiments, with reference to FIG. 9 and FIG. 10, FIG. 9 is a local enlarged view of a battery cell (10) provided in another embodiment of the present application; FIG. 10 is a local enlarged view of portion C in FIG. 9. A current gap (7) is formed between the side wall (14) and the protrusion (1323) along the radial direction (Z) of the contact portion. The current gap (7) communicates with two adjacent second current passages (1321).

[0143] A flow gap (7) is formed between the inner surface (141) of the side wall (14) and the surface of the protrusion (1323) facing the inner surface (141) of the side wall (14). A flow gap (7) can be formed between the protrusion (1323) and the side wall (14) by the protrusion (1323) not contacting the inner surface (141) of the side wall (14), and a flow gap (7) can be formed between the protrusion (1323) and the side wall (14) by a part of the protrusion (1323) contacting the inner surface (141) of the side wall (14) and another part not contacting the inner surface (141) of the side wall (14).

[0144] The flow gap (7) between the side wall (14) and the protrusion (1323) can connect two adjacent second flow passages (1321), and when the discharge in the first flow passage (6) flows into a specific second flow passage (1321), the discharge can flow through the flow gap (7) to another adjacent second flow passage (1321), thereby allowing the discharge in the first flow passage (6) to flow into the flow space (133) more quickly.

[0145] For example, when thermal runaway occurs in a battery cell (10), if the thermal runaway area of ​​the electrode assembly (2) approaches a specific second flow path (1321), the discharge generated by the thermal runaway of the electrode assembly (2) flows intensively into this second flow path (1321). When this second flow path (1321) fails to guide the discharge into the flow space (133) in a timely manner, the discharge that failed to flow into the flow space (133) in a timely manner flows into an adjacent second flow path (1321) through the flow gap (7), and can further flow into the flow space (133) quickly.

[0146] In some embodiments, with reference to FIGS. 10 to 12, FIG. 11 is a schematic diagram of the structure of the end wall (13) shown in FIG. 9; FIG. 12 is a DD cross-sectional view of the end wall (13) shown in FIG. 11. The joint portion (132) further comprises a main body portion (1324), the main body portion (1324) is installed enclosed by the outer edge of the wall main body (131) and protrudes from the wall main body (131) along a direction adjacent to the electrode assembly (2), and along a first direction (X), the main body portion (1324) has a first surface (13241) facing the electrode assembly (2), and a protrusion (1323) is installed on the first surface (13241).

[0147] The main body (1324) may be an annular structure installed around the outer edge of the wall main body (131). The first surface (13241) may be the surface of the main body (1324) closest to the electrode assembly (2) along the first direction (X). A protrusion (1323) is installed on the first surface (13241) so that the protrusion (1323) extends from the first surface (13241) along the direction closest to the electrode assembly (2). The second flow path (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).

[0148] The main body (1324) and the wall body (131) may be formed integrally; the main body (1324) and the wall body (131) may be installed as powder and connected to each other, and the method of connecting the two may be welding, bonding, etc.; the protrusion (1323) and the main body (1324) may be formed integrally; the protrusion (1323) and the main body (1324) may be installed as powder and connected to each other, and the method of connecting the two may be welding, bonding, etc.

[0149] In this embodiment, the main body (1324) serves to connect the wall body (131) and the protrusion (1323), and the main body (1324) is installed surrounded by the wall body (131) and protrudes from the wall body (131) along a direction close to the electrode assembly (2), thereby effectively improving the deformation resistance ability of the end wall (13).

[0150] In some embodiments, continuing to refer to FIGS. 10 to 12, along the first direction (X), the wall body (131) has a second surface (1311), the second surface (1311) is the surface of the wall body (131) closest to the electrode assembly (2), and the first surface (13241) is closer to the electrode assembly (2) than the second surface (1311).

[0151] 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 close to the electrode assembly (2), and the second surface (1311) and the sixth surface (1313) may be the same surface or different surfaces. In the embodiment illustrated in FIG. 12, 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).

[0152] In this embodiment, the first surface (13241) is closer to the electrode assembly (2) than the second surface (1311), thereby increasing the distance between the second surface (1311) and the electrode assembly (2), reducing the influence of the electrode assembly (2) on the pressure release mechanism (5) of the wall body (131), and effectively increasing the dimensions along the first direction (X) of the current guide space (133).

[0153] In some embodiments, referring to FIG. 10, a first groove (1325) is installed in the contact portion (132). Along the first direction (X), the main body portion (1324) has a third surface (13242) installed opposite to the first surface (13241), the first surface (13241) is closer to the electrode assembly (2) than the third surface (13242), and the first groove (1325) is recessed from the third surface (13242) in a direction closer to the electrode assembly (2) to form a protrusion (1323) protruding from the first surface (13241) on one side of the main body portion (1324) facing the electrode assembly (2).

[0154] The first groove (1325) corresponds to the protrusion (1323) individually. The first groove (1325) can be formed on the contact portion (132) through stamping. The first groove (1325) is formed on the third surface (13242) by stamping to correspond to the protrusion (1323) protruding from the first surface (13241) of the main body portion (1324), so that the protrusion (1323) and the main body portion (1324) can be formed integrally. The first groove (1325) may be a single groove and can be formed into the first groove (1325) through a single stamping during the processing process; the first groove (1325) may be a multi-stage groove and can be formed into a multi-stage groove step by step through multiple stampings during the processing process.

[0155] By forming a protrusion (1323) by installing a first groove (1325) in the joint portion (132), the difficulty of forming the protrusion (1323) can be effectively reduced, and the weight of the end wall (13) can be effectively reduced.

[0156] In some embodiments, continuing to refer to FIG. 10, the first groove (1325) is a multi-stage groove, and along the first direction (X), the first stage groove that is close to the electrode assembly (2) among the adjacent two stage grooves is installed on the bottom surface of the first stage groove that is away from the electrode assembly (2).

[0157] It can be understood that the first groove (1325) is a stepped groove. The first groove (1325) may be a 2-step groove, a 3-step groove, a 4-step groove, a 5-step groove, etc. As an example, in the embodiment illustrated in FIG. 10, the first groove (1325) is a 2-step groove.

[0158] By setting the first groove (1325) as a multi-stage groove, the forming force applied to the end wall (13) when forming each end groove is lowered, thereby reducing the risk of damage to the end wall (13) due to excessive forming force when forming the first groove (1325).

[0159] In some embodiments, the protrusion (1323) includes a first portion (13233) and a second portion (13234), and the multi-stage groove includes a first stage groove (13251) and a second stage groove (13252). The first stage groove (13251) is recessed from the third surface (13242) in a direction close to the electrode assembly (2) to form a first portion (13233) protruding from the first surface (13241) on one side of the main body portion (1324) facing the electrode assembly (2), and along the first direction (X), the first portion (13233) has a fourth surface (13233a) facing the electrode assembly (2). The second stage groove (13252) is recessed from the bottom surface of the first stage groove (13251) in a direction close to the electrode assembly (2) to form a second part (13234) protruding from the fourth surface (13233a) on one side of the first part (13233) facing the electrode assembly (2).

[0160] It must be explained that the protrusion (1323) may include only the first part (13233) and the second part (13234), or it may include other parts other than the first part (13233) and the second part (13234). If the protrusion (1323) includes only the first part (13233) and the second part (13234), the sum of the heights of the first part (13233) and the second part (13234) along the first direction is equal to the height (H) of the protrusion (1323). The multi-stage groove may include only the first stage groove (13251) and the second stage groove (13252), or it may include other stage grooves other than the first stage groove (13251) and the second stage groove (13252). For example, in the case where the multi-stage groove includes only the first stage groove (13251) and the second stage groove (13252), both the first stage groove (13251) and the second stage groove (13252) can be formed by stamping. During forming, the first stage groove (13251) is stamped on the third surface (13242) to form a corresponding first part (13233) protruding from the first surface (13241); then, the second stage groove (13252) is stamped on the groove bottom surface of the first stage groove (13251) to form a corresponding second part (13234) protruding from the fourth surface (13233a) of the first part (13233), thereby finally forming the first groove (1325) and the protrusion (1323).

[0161] The first part (13233) and the second part (13234) are both located within the side wall (14), and the first part (13233) may be in contact with the inner surface of the side wall (14) and may have a gap between them, and the second part (13234) may be in contact with the inner surface of the side wall (14) and may have a gap between them.

[0162] In this embodiment, by installing a first step groove (13251) in the main body (1324), a first part (13233) of the protrusion (1323) can be formed accordingly, and by installing a second step groove (13252) in the first part (13233), a second part (13234) of the protrusion (1323) can be formed accordingly, thereby reducing the difficulty of molding the protrusion (1323).

[0163] In some embodiments, continuing to refer to FIG. 10, along the radial direction (Z) of the contact portion, the first portion (13233) has a first side (13233b) of the inner surface (141) facing the side wall (14), and the second portion (13234) has a second side (13234a) of the inner surface (141) facing the side wall (14), the first side (13233b) is closer to the inner surface (141) of the side wall (14) than the second side (13234a), and a flow gap (7) is formed between the second side (13234a) and the inner surface (141) of the side wall (14), and the flow gap (7) connects two adjacent second flow passages (1321).

[0164] A current-conducting gap (7) is formed between the second side (13234a) and the inner surface (141) of the side wall (14), that is, the second side (13234a) and the inner surface (141) of the side wall (14) do not come into contact. Of course, a current-conducting gap (7) may be formed between the first side (13233b) and the inner surface (141) of the side wall (14), or they may come into direct contact.

[0165] As an example, the first side (13233b) and the second side (13234a) are both arc planes with a central axis extending along the first direction (X), and the central axis of both the first side (13233b) and the second side (13234a) overlaps with the central axis of the inner surface (141) of the side wall (14).

[0166] In this embodiment, the flow gap (7) between the second side (13234a) and the inner surface (141) of the side wall (14) can connect two adjacent second flow passages (1321), and when the discharge in the first flow passage (6) flows into a specific second flow passage (1321), the discharge can flow into another adjacent second flow passage (1321) through the flow gap (7), thereby allowing the discharge in the first flow passage (6) to flow into the flow space (133) more quickly.

[0167] In some embodiments, referring to FIG. 10, a second groove (134) is installed at a position corresponding to the main body part (1324) on one side of the end wall (13) facing away from the electrode assembly (2), and a third surface (13242) is the bottom surface of the groove of the second groove (134).

[0168] As an example, the shape of the second groove (134) and the main body (1324) are identical, and both have an annular structure.

[0169] The second groove (134) can be formed on the end wall (13) by stamping. The second groove (134) is formed by stamping on one side of the end wall (13) and is formed corresponding to the main body part (1324) on the other side of the end wall (13), so that the wall main body (131) and the main body part (1324) can be formed as a single unit. When 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).

[0170] In this embodiment, by installing a second groove (134) in the end wall (13) and forming the main body part (1324) in correspondence, the difficulty of molding the main body part (1324) can be effectively reduced.

[0171] In some embodiments, referring to FIG. 10, the end wall (13) and the side wall (14) are installed as a single piece, and at least a portion of the main body (1324) is received within the side wall (14) to form a positional interlock with the side wall (14).

[0172] The end wall (13) and the side wall (14) are installed as separate parts, that is, the end wall (13) and the side wall (14) are two parts that are not integrally formed. As an example, the end wall (13) is the end cover (12) of the housing (1), and the end wall (13) is welded to the side wall (14) to be connected.

[0173] The portion of the main body (1324) accommodated within the side wall (14) forms a positional interlock with the side wall (14) so ​​that the outer surface of the main body (1324) comes into contact with the inner surface (141) of the side wall (14). As an example, the portion of the main body (1324) accommodated within the side wall (14) forms an interference fit with the side wall (14).

[0174] In this embodiment, by forming a positional interlock with the side wall (14) on the main body (1324), the difficulty of assembling the end wall (13) and the side wall (14) can be effectively reduced. For example, in the case where the end wall (13) and the side wall (14) are connected by welding, after the main body (1324) forms a positional interlock with the side wall (14) during the assembly process, the end wall (13) and the side wall (14) can be welded together more easily, thereby reducing the difficulty of welding both and improving the quality of welding both.

[0175] In some embodiments, continuing to refer to FIG. 10, the end wall (13) additionally includes an edge portion (135), the edge portion (135) is installed surrounding the outer edge of the main body portion (1324), and the edge portion (135) is in contact with one end of the side wall (14) along the direction in which the end wall (13) faces the electrode assembly (2).

[0176] The edge portion (135) is an annular structure installed around the outer edge of the main body portion (1324). The outer edge of the edge portion (135) is the outer edge of the end wall (13).

[0177] As an example, the side wall (14) is part of the housing (1), and the housing (1) forms an opening only at one end along the first direction (X), and the edge portion (135) is in contact with the end of the housing (1) that forms an opening in the direction in which the end wall (13) faces the electrode assembly (2), and the edge portion (135) is welded to the side wall (14) and connected.

[0178] In this embodiment, the edge portion (135) is attached to the side wall (14) to limit the end wall (13), and the end wall (13) can be limited to move along the direction close to the electrode assembly (2).

[0179] In some embodiments, the wall body (131) and the contact portion (132) are formed integrally.

[0180] As an example, a second groove (134) is installed at a position corresponding to the contact portion (132) on one side of the end wall (13) facing the electrode assembly (2), and the second groove (134) is formed by stamping.

[0181] In an embodiment in which the end wall (13) additionally includes an edge portion (135), the edge portion (135), the contact portion (132), and the wall body (131) can be formed integrally.

[0182] In this embodiment, the wall body (131) and the joint portion (132) are integrally molded so that the connection strength between the joint portion (132) and the wall body (131) can be effectively improved.

[0183] In some embodiments, continuing to refer to FIG. 12, along the first direction (X), the wall body (131) has a fifth surface (1312), the fifth surface (1312) is the surface of the end wall (13) furthest from the electrode assembly (2), and the pressure release mechanism (5) is closer to the electrode assembly (2) than the fifth surface (1312) (not shown in FIG. 12).

[0184] The fifth surface (1312) may be a cross-section along the first direction (X) of the battery cell (10). The fifth surface (1312) is used to contact an external member. In an embodiment where the end wall (13) is electrically connected to the electrode assembly (2), the end wall (13) acts as one output electrode of the battery cell (10), and the external member may be a bus member for electrically connecting to the end wall (13); in an embodiment where the end wall (13) is insulated from the electrode assembly (2), the end wall (13) may be a member located in the bottom region of the battery cell (10), and the external member may be a box body (20) within the battery (100), and after the battery cell (10) is placed within the box body (20), the fifth surface (1312) may act as the bottom surface of the battery cell (10) and contact the box body (20).

[0185] In this embodiment, it must be explained that the pressure release mechanism (5) may be a pressure release member installed in powder form with the wall body (131), and the pressure release mechanism (5) may be a structure formed integrally with the wall body (131).

[0186] In this embodiment, the pressure release mechanism (5) is closer to the electrode assembly (2) than to the fifth surface (1312), thereby increasing the distance between the pressure release mechanism (5) and the external member when the fifth surface (1312) contacts the external member, reducing the influence of the external member on the pressure release mechanism (5), and reducing the risk of premature operation of the pressure release mechanism (5) due to the impact force of the external member.

[0187] In some embodiments, referring to FIG. 12, a third groove (1314) is installed in the wall body (131), and the third groove (1314) is recessed in a direction close to the electrode assembly (2) from the fifth surface (1312), and a pressure release groove (1316) is installed in the groove bottom wall (13141) of the third groove so that the groove bottom wall (13141) of the third groove forms a pressure release mechanism (5) at a position corresponding to the pressure release groove (1316).

[0188] The third groove (1314) can be formed by stamping on the wall body (131). The projection of the third groove (1314) along the first direction (X) can be rectangular, circular, elliptical, etc. The groove bottom wall (13141) of the third groove is a part of the wall body (131) located at the bottom of the third groove (1314) along the depth direction of the third groove (1314).

[0189] The pressure release groove (1316) may be installed on one side of the bottom wall (13141) of the third groove facing the electrode assembly (2), and may also be installed on one side of the bottom wall (13141) of the third groove facing away from the electrode assembly (2).

[0190] By installing a pressure release groove (1316) on the bottom wall (13141) of the third groove, a pressure release mechanism (5) is formed in conjunction with the wall body (131) and formed integrally with the wall body (131). The pressure release mechanism (5) is the bottom wall of the pressure release groove (1316), and the bottom wall of the pressure release groove (1316) is a part of the bottom wall (13141) of the third groove located at the bottom of the pressure release groove (1316) along the depth direction of the pressure release groove (1316).

[0191] As an example, as illustrated in FIG. 12, a recess is installed on one side of the bottom wall (13141) of the third groove facing away from the electrode assembly (2), and a reinforcing rib (1315) is formed on one side of the bottom wall (13141) of the third groove facing the electrode assembly (2) at a position corresponding to the recess. The reinforcing rib (1315) is approximately X-shaped, and along the first direction (X), the surface of one end of the reinforcing rib (1315) facing the electrode assembly (2) is the surface (second surface (1311)) of the wall body (131) closest to the electrode assembly (2). The pressure release groove (1316) is an annular groove, and the pressure release groove (1316) is surrounded on the outside of the reinforcing rib (1315). The pressure release groove (1316) defines a pressure release area, and the reinforcing rib (1315) is located in the pressure release area. When the battery cell (10) releases pressure, the wall body (131) cracks along the pressure release groove (1316) to open the pressure release area. Reinforcing ribs (1315) are used to reinforce the pressure release area, thereby improving the deformation resistance of the pressure release area and reducing the risk of the pressure release mechanism (5) rupturing prematurely due to fatigue caused by deformation of the pressure release area due to internal pressure changes of the battery cell (10).

[0192] In this embodiment, a third groove (1314) is installed in the wall body (131) in a direction facing the electrode assembly (2) from the fifth surface (1312), and a pressure release groove (1316) is installed in the groove bottom wall (13141) of the third groove to form a corresponding pressure release mechanism (5), thereby implementing the pressure release mechanism (5) closer to the electrode assembly (2) than the fifth surface (1312), and the implementation method is simple.

[0193] In some embodiments, a pressure release groove (1316) is installed in the wall body (131) so that the wall body (131) forms a pressure release mechanism (5) at a position corresponding to the pressure release groove (1316).

[0194] The forming method of the pressure release groove (1316) is varied, such as forming by stamping, forming by laser etching, forming by milling, etc. The pressure release groove (1316) may be a groove extending along a closed trajectory, and the closed trajectory may be a circular trajectory, a rectangular trajectory, etc.; the pressure release groove (1316) may be a groove extending along a non-closed trajectory, and the non-closed trajectory may be an H-shaped trajectory, a V-shaped trajectory, a C-shaped trajectory, a Y-shaped trajectory, etc.

[0195] By installing a pressure release groove (1316) in the wall body (131) and forming an integrated pressure release mechanism (5) in correspondence, the molding method of the pressure release mechanism (5) is simple and the reliability of the pressure release mechanism (5) is higher.

[0196] In some embodiments, continuing to refer to FIG. 9, the battery cell (10) may additionally include a current collecting member (4), the current collecting member (4) is installed between the end wall (13) and the electrode assembly (2) along the first direction (X), the current collecting member (4) is electrically connected to the electrode assembly (2) and the end wall (13), the contact portion (132) is directly contacted to the current collecting member (4), and the current collecting member (4) is directly contacted to the tab (21).

[0197] The current collecting member (4) is a conductive member that implements an electrical connection between the electrode assembly (2) and the end wall (13). The current collecting member (4) is located within the housing (1) and is positioned between the end wall (13) and the electrode assembly (2). The current collecting member (4) can be connected by welding to the tab (21) at the end of the electrode assembly (2), and the current collecting member (4) can also be connected by welding to the joint (132).

[0198] In this embodiment, the contact portion (132) is indirectly contacted to the tab (21) of the electrode assembly (2) through the current collecting member (4), and by implementing an electrical connection between the electrode assembly (2) and the end wall (13) through the current collecting member (4), the difficulty of the electrical connection between the electrode assembly (2) and the end wall (13) can be reduced.

[0199] In some embodiments, a first central hole (23) is installed in the electrode assembly (2), and a second central hole (41) is installed in the current collecting member (4), and the second central hole (41) is connected to the first central hole (23) and the current-conducting space (133).

[0200] As an example, the electrode assembly (2) is a wound structure, and the first central hole (23) is located at the 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 installed coaxially, and the pore size of the first central hole (23) is larger than the pore size of the second central hole (41).

[0201] When thermal runaway occurs in the battery cell (10), the discharge generated from the electrode assembly (2) can sequentially pass through the first central hole (23) and the second central hole (41) and flow into the flow path space (133), thereby further shortening the time from the occurrence of thermal runaway in the battery cell (10) until the pressure release of the battery cell (10) through the pressure release mechanism (5) begins, so that the pressure release mechanism (5) can operate more promptly.

[0202] In some embodiments, the housing (1) includes a case (11) and an end cover (12). An opening is formed at at least one end along a first direction (X) of the case (11), and the end cover (12) closes the opening. At least one end cover (12) is a side wall (13), and the case (11) includes a side wall (14).

[0203] The case (11) may have an opening formed at only one end along the first direction (X), and the end cover (12) may be installed as a single unit in correspondence. The case (11) may have openings formed at both ends along the first direction (X), and two end covers (12) may be installed in correspondence, and the two end covers (12) each close the two opposing openings of the case (11), and one end cover (12) may be a single wall (13), or both end covers (12) may be single walls (13). It can be understood that the single wall (13) and the side wall (14) are installed as separate units.

[0204] In this embodiment, at least one end cover (12) is a wall (13), and a pressure release mechanism (5) is installed on at least one end cover (12) to reduce the difficulty of molding or mounting the pressure release mechanism (5), and a second flow path (1321) is installed on the end cover (12) to reduce the difficulty of molding the second flow path (1321).

[0205] In some embodiments, the battery cell (10) is a cylindrical battery cell.

[0206] It can be understood that the battery cell (10) is cylindrical and the axial direction of the battery cell (10) is parallel to the first direction (X).

[0207] An embodiment of the present application provides a battery (100) comprising a battery cell (10) provided in any one of the embodiments described above.

[0208] An embodiment of the present application provides an electric device comprising a battery cell (10) provided in any one of the embodiments described above, wherein the battery cell (10) is used to provide electric energy to the electric device.

[0209] Additionally, referring to FIGS. 3 through 7, an embodiment of the present application further provides a cylindrical battery cell comprising a housing (1), an electrode assembly (2), and a current collector (4), wherein both the electrode assembly (2) and the current collector (4) are accommodated within the housing (1). The housing (1) comprises a case (11) and an end cover (12), wherein the case (11) forms an opening only at one end along a first direction (X), the end cover (12) closes the opening, and the first direction (X) is parallel to the axial direction of the housing (1). The electrode assembly (2) comprises a main body (22) and a tab (21), wherein the tab (21) is installed 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. An electrode terminal (3) is installed on the wall of the case (11) facing the end cover (12), and the electrode terminal (3) and the positive tab are electrically connected through one current collecting member (4), and the end cover (12) and the negative tab are electrically connected through another current collecting member (4).

[0210] Here, the end cover (12) is the end wall (13) of the housing (1), and the case (11) includes a side wall (14) surrounding the end wall (13), and a first current passage (6) is formed between the negative tab of the electrode assembly (2) and the side wall (14). The end wall (13) includes a wall body (131) and a contact portion (132), and a pressure release groove (1316) is installed in the wall body (131) so that the wall body (131) forms a pressure release mechanism (5) at a position corresponding to the pressure release groove (1316), and the contact portion (132) is installed surrounding the outer edge of the wall body (131). Along the first direction (X), the contact portion (132) protrudes from the wall body (131) along the direction adjacent to the electrode assembly (2) and is directly contacted to the current collecting member (4). The connecting portion (132) and the wall body (131) jointly define a flow space (133), and a second flow passage (1321) is installed in the connecting portion (132), and the second flow passage (1321) connects the flow space (133) and the first flow passage (6).

[0211] The contact portion (132) includes a main body portion (1324) and a plurality of protrusions (1323), the main body portion (1324) is installed surrounded by the outer edge of the wall main body (131) and protrudes from the wall main body (131) along a direction close to the electrode assembly (2), and along a first direction (X), the main body portion (1324) has a first surface (13241) facing the electrode assembly (2), and the protrusions (1323) are installed on the first surface (13241) and the protrusions (1323) are in direct contact with the current collector member (4). A second groove (134) is installed at a position corresponding to the main body part (1324) on one side of the end wall (13) facing the electrode assembly (2), and a first groove (1325) is installed in the contact part (132). Along the first direction (X), the first groove (1325) is sunk from the bottom surface of the second groove (134) toward the electrode assembly (2) to form a protrusion (1323) protruding from the first surface (13241) on one side of the main body part (1324) facing the electrode assembly (2). A plurality of protrusions (1323) are uniformly distributed along the circumferential direction (Y) of the contact part, and a second flow path (1321) is formed between two adjacent protrusions (1323). Along the first direction (X), the height of the protrusion (1323) is H, and the protrusion (1323) has a contact surface (1322) that is in direct contact with the current collector (4), and along the radial direction (Z) of the contact portion, the width of the contact surface (1322) is W; 0.1W≤H≤0.5W, 5mm≥H≥0.5mm.

[0212] It should be explained that the embodiments of the present application and the features in the embodiments can be combined with one another, unless they conflict.

[0213] The above embodiments are intended only to illustrate the technical solutions of the present application and are not intended to limit the present application; various modifications and changes are possible to those skilled in the art. All modifications, equivalent substitutions, improvements, etc., made within the gist and principles of the present application shall be included within the scope of protection of the present application. Explanation of the symbols

[0214] 1-Housing; 11-Case; 12-End cover; 13-Side wall; 131-Wall body; 1311-Second surface; 1312-Fifth surface; 1313-Sixth surface; 1314-Third groove; 13141-Floor wall of the groove of the third groove; 1315-Reinforcing rib; 1316-Pressure release groove; 132-Contact part; 1321-Second flow passage; 1322-Contact surface; 1323-Protrusion; 13231-First step; 13232-Second step; 13233-First part; 13233a-Fourth surface; 13233b-First side; 13234-Second part; 13234a-Second side; 1324-Body part; 13241-1st surface; 13242-3rd surface; 1325-1st groove; 13251-1st stage groove; 13252-2nd stage groove; 133-Current conduction space; 134-2nd groove; 135-Edge portion; 14-Side wall; 141-Inner circumference; 2-Electrode assembly; 21-Tap; 22-Body portion; 23-1st central hole; 3-Electrode terminal; 4-Current collector; 41-2nd central hole; 5-Pressure relief mechanism; 6-1st current conduction passage; 7-Current conduction gap; 10-Battery cell; 20-Box body; 201-1st box body; 202-2nd box body; 100-Battery; 200-Controller; 300-Motor; 1000-Vehicle; Q-1st circle; U-1st connecting line; V-2nd connecting line; X-1st direction; Y-Circumferential direction of the weld; Z-Radical direction of the weld.

Claims

Claim 1 A battery cell comprising: a housing including a end wall and a side wall, wherein the end wall is installed at one end along a first direction of the side wall and the side wall is installed surrounding the end wall; an electrode assembly accommodated within the housing, wherein one end of the electrode assembly facing the end wall has a tab and a first flow path is formed between the tab and the side wall, wherein the end wall comprises a wall body and a contact portion, wherein a pressure release mechanism is installed in the wall body and the contact portion is installed surrounding the outer edge of the wall body; wherein, along the first direction, the contact portion protrudes from the wall body along a direction adjacent to the electrode assembly and is directly or indirectly contacted with the tab; wherein the contact portion and the wall body jointly define a flow path space, and a second flow path is installed in the contact portion, and the second flow path is connected to the flow path space and the first flow path. Claim 2 A battery cell according to claim 1, wherein a plurality of the second current passages are installed in the joint portion, and the plurality of the second current passages are installed spaced apart along the circumferential direction of the joint portion. Claim 3 A battery cell according to claim 1 or 2, wherein, along the first direction, the contact portion has a contact surface, the contact surface is the surface of the contact portion closest to the electrode assembly, and the second flow path is a notch groove that penetrates the contact portion along the radial direction of the contact portion and extends to the contact surface along the first direction. Claim 4 A battery cell according to any one of claims 1 to 3, wherein the contact portion comprises a plurality of protrusions that contact the tab directly or indirectly, and a second flow path is formed between two adjacent protrusions along the circumferential direction of the contact portion. Claim 5 In claim 4, the protrusion has a contact surface, the contact surface is used to make direct or indirect contact with the tab to make an electrical connection between the end wall and the electrode assembly; along the first direction, the height of the protrusion is H; along the radial direction of the contact portion, the width of the contact surface is W; and a battery cell having 0.1W ≤ H ≤ 0.5W. Claim 6 A battery cell according to claim 4 or 5, wherein along the first direction, the height of the protrusion is H and 5mm≥H≥0.5mm. Claim 7 A battery cell according to any one of claims 4 to 6, wherein along the circumferential direction of the contact portion, the protrusion has opposing first and second portions; the projection of the outer edge of the portion wall along the first direction forms a first circle, and along the first direction, the centrifugal connecting line between the first portion and the first circle is a first connecting line, the centrifugal connecting line between the second portion and the first circle is a second connecting line, and the angle between the first connecting line and the second connecting line is α, and 15° ≤ α ≤ 60°. Claim 8 A battery cell according to any one of claims 4 to 7, wherein a plurality of the protrusions are uniformly arranged along the circumferential direction of the contact portion. Claim 9 A battery cell according to any one of claims 4 to 8, wherein a flow guide gap is formed between the side wall and the protrusion along the radial direction of the contact portion; and the flow guide gap connects two adjacent second flow guide passages. Claim 10 A battery cell according to any one of claims 4 to 9, wherein the contact portion further comprises a body portion installed enclosed by the outer edge of the wall body and protruding from the wall body along a direction adjacent to the electrode assembly, and along the first direction, the body portion has a first surface facing the electrode assembly, and the protrusion is installed on the first surface. Claim 11 In claim 10, along the first direction, the wall body has a second surface, the second surface 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, a battery cell. Claim 12 A battery cell according to claim 10 or 11, wherein a first groove is installed in the contact portion; along a first direction, the main body portion has a third surface installed 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 in a direction closer to the electrode assembly to form the protrusion protruding from the first surface on one side of the main body portion facing the electrode assembly. Claim 13 A battery cell according to claim 12, wherein the first groove is a multi-stage groove, and along the first direction, the first groove adjacent to the electrode assembly among the adjacent two-stage grooves is installed on the groove bottom surface of the first groove away from the electrode assembly. Claim 14 A battery cell according to claim 13, wherein the protrusion comprises a first portion and a second portion, and the multi-stage groove is recessed from the third surface in a direction adjacent to the electrode assembly to form the first portion protruding from the first surface on one side of the main body portion facing the electrode assembly, and along the first direction, the first portion has a first stage groove having a fourth surface facing the electrode assembly; and a second stage groove is recessed from the bottom surface of the first stage groove in a direction adjacent to the electrode assembly to form the second portion protruding from the fourth surface on one side of the first portion facing the electrode assembly. Claim 15 A battery cell according to claim 14, wherein, along the radial direction of the contact portion, the first portion has a first side of an inner surface facing the side wall, and the second portion has a second side of an inner surface facing the side wall, the first side is closer to the inner surface of the side wall than the second side, and a current gap is formed between the second side and the inner surface of the side wall, and the current gap connects two adjacent second current passages. Claim 16 A battery cell according to any one of claims 12 to 15, wherein one side of the end wall facing away from the electrode assembly has a second groove installed at a position corresponding to the main body, and the third surface is the bottom surface of the second groove. Claim 17 A battery cell according to any one of claims 10 to 16, wherein the end wall and the side wall are installed as powder, and at least a portion of the main body is received within the side wall to form a positional interlock with the side wall. Claim 18 A battery cell according to claim 17, wherein the end wall further comprises an edge portion, said edge portion is installed surrounding the outer edge of the main body portion, said edge portion is in contact with one end of the side wall along the direction in which the end wall faces the electrode assembly. Claim 19 A battery cell according to any one of claims 1 to 18, wherein the wall body and the contact portion are integrally molded. Claim 20 A battery cell according to any one of claims 1 to 19, wherein, along the first direction, the wall body has a fifth surface, the fifth surface 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. Claim 21 A battery cell according to claim 20, wherein a third groove is installed in the wall body, the third groove is recessed from the fifth surface in a direction close to the electrode assembly, and a pressure release groove is installed in the groove bottom wall of the third groove so that the groove bottom wall of the third groove forms the pressure release mechanism at a position corresponding to the pressure release groove. Claim 22 A battery cell according to any one of claims 1 to 20, wherein a pressure release groove is installed in the wall body and the wall body forms the pressure release mechanism at a position corresponding to the pressure release groove. Claim 23 A battery cell according to any one of claims 1 to 22, wherein the battery cell further comprises a current collecting member installed between the end wall and the electrode assembly along the first direction, the current collecting member being electrically connected to the electrode assembly and the end wall, the contact portion being directly contacted to the current collecting member, and the current collecting member being directly contacted to the tab. Claim 24 A battery cell according to claim 23, wherein a first central hole is installed in the electrode assembly and a second central hole is installed in the current collecting member, and the second central hole communicates with the first central hole and the current-conducting space. Claim 25 A battery cell according to any one of claims 1 to 24, wherein the housing comprises a case having an opening formed at least one end along the first direction; and an end cover closing the opening, wherein at least one of the end covers is the end wall and the case comprises the side wall. Claim 26 A battery cell according to any one of claims 1 to 25, wherein the battery cell is a cylindrical battery cell. Claim 27 A battery comprising a battery cell according to any one of claims 1 to 26. Claim 28 An electric device comprising a battery cell according to any one of claims 1 to 26, wherein the battery cell is used to provide electric energy to the electric device.

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