Battery cell, battery, and electric device

Abstract

A battery cell, a battery, and an electric device are disclosed. The battery cell includes a case, an electrode assembly, and an electrode terminal. The case includes a wall portion provided with an electrode lead-out hole. At least a portion of the electrode assembly is accommodated in the case, and the electrode assembly includes a tab. The electrode terminal is provided to the wall portion and covers at least a portion of the electrode lead-out hole. The electrode terminal is electrically connected to the tab. The electrode terminal is deformable in a case where an internal pressure or temperature of the case reaches a threshold value, so as to cause an internal space of the case to communicate with an external space via the electrode lead-out hole.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese patent application 202310389480.4, filed on April 12, 2023, entitled “Battery cell, battery and electrical device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of batteries, and in particular to a battery cell, a battery, and an electrical device. Background Technology

[0004] With the development of battery technology, battery cells are being applied in more and more fields, gradually replacing traditional fossil fuels in the automotive power sector. Battery cells can store chemical energy and controllably convert it into electrical energy. In recyclable battery cells, the active materials can be reactivated through charging after discharge, allowing for continued use.

[0005] Improving the reliability of individual battery cells is an important research direction in the industry. Summary of the Invention

[0006] This application provides a battery cell, a battery, and an electrical device that can improve reliability.

[0007] In a first aspect, this application provides a battery cell, including a casing, an electrode assembly, and electrode terminals. The casing includes a wall portion with electrode lead-out holes. At least a portion of the electrode assembly is housed within the casing, and the electrode assembly includes tabs. Electrode terminals are disposed on the wall portion and cover at least a portion of the electrode lead-out holes. The electrode terminals are electrically connected to the tabs. At least a portion of the electrode terminals can deform when the internal pressure or temperature of the casing reaches a threshold, thereby allowing the internal space of the casing to communicate with the external space through the electrode lead-out holes and venting gas from the casing.

[0008] When the internal pressure or temperature of the casing reaches a threshold, the above-mentioned technical solution can utilize the deformation of the electrode terminals to connect the internal space of the casing with the external space, thereby releasing the internal gas and internal pressure of the casing and reducing the risk of battery cell explosion. Compared with the solution of setting an additional pressure relief mechanism on the casing, the above-mentioned technical solution can also simplify the structure of the battery cell and reduce the cost of the battery cell.

[0009] In some embodiments, at least a portion of the electrode terminals can detach from the wall when the internal pressure or temperature of the housing reaches a threshold.

[0010] When at least a portion of the electrode terminal detaches from the wall, at least a portion of the electrode lead-out hole is no longer covered by the electrode terminal. The electrode lead-out hole can connect the internal space of the casing with the external space, thereby releasing the internal gas of the battery cell and reducing the internal pressure and temperature of the battery cell.

[0011] In some embodiments, the electrode terminal includes a protrusion that extends radially out of the wall of the electrode lead-out hole, the protrusion being located on the side of the wall facing the electrode assembly, and the protrusion being deformable when the internal pressure or temperature of the housing reaches a threshold.

[0012] During normal operation of a battery cell, the wall can prevent protrusions from emerging, reducing the risk of electrode terminals detaching from the electrode lead-out holes. When the internal pressure or temperature of the casing reaches a threshold, the protrusions can deform, causing the wall to no longer prevent them from emerging. This allows the electrode terminals to detach from the electrode lead-out holes, enabling communication between the internal and external spaces of the casing. Gas inside the casing can then escape through the electrode lead-out holes, thereby reducing the risk of battery cell explosion.

[0013] In some embodiments, the maximum dimension of the protrusion protruding from the electrode lead-out hole is L1, and the minimum distance between the periphery of the protrusion and the hole wall of the electrode lead-out hole is L2; ​​L1 and L2 satisfy: 0.1≤L1 / L2≤0.5.

[0014] Setting the L1 / L2 value to less than or equal to 0.5 allows for timely deformation when the internal pressure or temperature of the casing reaches a threshold, improving the reliability of the battery cell. Setting the L1 / L2 value to greater than or equal to 0.1 improves the stability of the electrode terminals on the wall, reducing the risk of electrode terminals detaching when the battery cell is subjected to external impact.

[0015] In some embodiments, the maximum dimension of the wall of the protruding electrode lead-out hole is L1, and the maximum thickness of the protruding part is T1; L1 and T1 satisfy: 0.25mm 2 ≤L1×T1≤25mm 2 .

[0016] The value of L1×T1 is limited to less than or equal to 25 mm. 2 This allows for timely deformation of the battery cell when the internal pressure or temperature of the casing reaches a threshold, improving the reliability of the individual battery cells. The value of L1×T1 is limited to greater than or equal to 0.25 mm. 2 This can improve the stability of the electrode terminals on the wall and reduce the risk of electrode terminals falling off when the battery cell is subjected to external impact.

[0017] In some embodiments, T1 is 0.5mm-5mm. Limiting T1 to 0.5mm-5mm allows for timely deformation when the internal pressure or temperature of the casing reaches a threshold, and reduces the risk of electrode terminals detaching when the battery cell is subjected to external impact.

[0018] In some embodiments, the thickness of at least a portion of the protrusion gradually decreases in the direction from the central axis of the electrode lead-out hole to the outer periphery of the protrusion.

[0019] By setting a variable thickness zone with gradually decreasing thickness on the protrusion, the protrusion can be more easily deformed under internal pressure, thereby releasing pressure in time and improving the reliability of the battery cell.

[0020] In some embodiments, the protrusion has a first surface facing the wall, the wall has a second surface facing the protrusion, the second surface is perpendicular to the thickness direction of the wall, the first surface is inclined relative to the second surface toward the electrode assembly, and in the thickness direction of the wall, the distance between the end of the first surface away from the electrode lead hole and the second surface is greater than the distance between the end of the first surface near the electrode lead hole and the second surface.

[0021] When the internal pressure or temperature of the casing reaches a threshold, the tilted first surface can guide the deformation of the protrusion, making it easier for the protrusion to pass through the electrode lead hole, thereby releasing pressure in time and improving the reliability of the battery cell.

[0022] In some embodiments, the electrode terminal includes a terminal body and a first limiting portion connected to each other. At least a portion of the terminal body is received in an electrode lead-out hole, and the first limiting portion is located on the side of the wall facing the electrode assembly and protrudes from the outer peripheral surface of the terminal body. The first limiting portion includes a protrusion.

[0023] By configuring the terminal body to extend into the electrode lead-out hole, it is easy to connect the electrode terminal to other components outside the battery cell. The wall portion forms a barrier against the protrusion, thereby preventing the electrode terminal from detaching from the inside of the housing.

[0024] In some embodiments, the first limiting portion has a weak portion, and the first limiting portion can be bent or broken along the weak portion when the internal pressure or temperature of the housing reaches a threshold.

[0025] By setting a weak part on the first limiting part, the difficulty of deformation of the first limiting part can be reduced when the internal pressure or temperature of the shell reaches a threshold, so that the first limiting part can be bent or broken at a preset position, thereby connecting the internal space of the shell with the external space through the electrode lead-out hole, reducing the risk of battery cell explosion.

[0026] In some embodiments, at least a portion of the projection of the weak portion in the thickness direction of the wall is located within the electrode lead-out hole.

[0027] The above technical solution can make the bend of the first limiting part closer to the electrode lead-out hole when the internal pressure or temperature of the shell reaches a threshold, thereby making it easier for the first limiting part to pass through the electrode lead-out hole.

[0028] In some embodiments, the first limiting portion includes a protrusion and a connecting portion, the connecting portion being used to connect the protrusion and the terminal body, and the projection of the connecting portion in the thickness direction of the wall portion being located between the outer peripheral surface of the terminal body and the wall of the electrode lead-out hole. A weak portion is provided in the connecting portion.

[0029] When the internal pressure or temperature of the housing reaches a threshold, the protrusion can be flipped over as the weak part bends to avoid the wall and pass through the electrode lead-out hole. By placing the weak part at the connection part, the limitation on the strength of the protrusion can be reduced, and the shape design of the protrusion can be more flexible.

[0030] In some embodiments, the electrode terminal is provided with a groove, and a weak portion is formed at the bottom of the groove. By forming the weak portion by creating a groove, the forming efficiency of the electrode terminal can be improved.

[0031] In some embodiments, a groove is provided on the surface of the first limiting portion facing the wall portion.

[0032] In some embodiments, a groove is provided on the surface of the first limiting portion away from the wall portion. When the internal pressure or temperature of the housing reaches a threshold, the groove can provide space for material flow, facilitating bending of the first limiting portion.

[0033] In some embodiments, the electrode terminal is provided with a recess. Along the thickness direction of the wall portion, the recess is recessed from the inside of the housing toward the outside of the housing; at least a portion of the recess is provided on the side of the terminal body facing the electrode tab.

[0034] When the internal pressure or temperature of the outer shell reaches a threshold, the first limiting part bends; the recess can provide space for the flow of material during the bending process of the first limiting part, thereby reducing the resistance of the bending of the first limiting part and enabling the first limiting part to pass through the electrode lead-out hole in time.

[0035] In some embodiments, the recess includes a first side surface and a second side surface. The first side surface is disposed on the outer side of the second side surface along the radial direction of the electrode lead-out hole. The first side surface is connected to the bottom surface of the recess and is inclined toward the side away from the central axis of the electrode terminal.

[0036] By tilting the first side, more space can be provided for material flow when the first limiting part bends, reducing the resistance to bending of the first limiting part.

[0037] In some embodiments, the recess includes a first side surface and a second side surface. The first side surface is disposed on the outer side of the second side surface along the radial direction of the electrode lead-out hole. The second side surface is connected to the bottom surface of the recess and is inclined toward the side close to the central axis of the electrode terminal.

[0038] By tilting the second side, the risk of interference between the second and first sides can be reduced when the first side deforms due to material flow, and the resistance to bending of the first limiting part can be decreased.

[0039] In some embodiments, the first limiting portion can be bent toward the recess when the internal pressure or temperature of the housing reaches a threshold.

[0040] When the internal pressure or temperature of the outer shell reaches a threshold, the first limiting part bends towards the concave part to allow the material to flow toward the concave part, reducing the resistance of the bending of the first limiting part and enabling the first limiting part to pass through the electrode lead-out hole in a timely manner.

[0041] In some embodiments, the first limiting portion is formed by folding a portion of the electrode terminal.

[0042] During assembly, the electrode terminal can be inserted into the interior of the housing through the electrode lead-out hole, and then a part of the electrode terminal can be folded over to form the first limiting part, thereby fixing the electrode terminal to the wall.

[0043] In some embodiments, the terminal body includes a terminal protrusion and a recess surrounding the terminal protrusion. In the thickness direction of the wall portion, the end face of the terminal protrusion facing the electrode is closer to the electrode than the first limiting portion.

[0044] The first limiting part is less likely to interfere with the contact between the terminal protrusion and other components, thereby reducing over-positioning and lowering the risk of poor contact between the terminal protrusion and other components due to unevenness of the first limiting part, thus improving the overcurrent capacity and reliability of the battery cell.

[0045] In some embodiments, the electrode terminal further includes a second limiting portion, which protrudes from the outer peripheral surface of the terminal body and is disposed outside the wall portion. At least a portion of the wall portion is located between the protrusion and the second limiting portion in the thickness direction of the wall portion. The wall portion may be confined between the first and second limiting portions to restrict relative movement between the electrode terminal and the wall portion.

[0046] In some embodiments, in the radial direction of the electrode lead-out hole, the end of the second limiting portion away from the terminal body extends beyond the end of the first limiting portion away from the terminal body.

[0047] In the radial direction of the electrode lead-out hole, the second limiting portion has a larger dimension than the first limiting portion. This increases the exposed area of ​​the electrode terminal, facilitating connection between the electrode terminal and external busbar components, increasing the connection area between the electrode terminal and the busbar component, and improving current carrying capacity. In the radial direction of the electrode lead-out hole, the first limiting portion has a larger dimension than the second limiting portion, making it more susceptible to deformation when the internal pressure or temperature of the casing reaches a threshold, thus allowing for timely pressure relief and improving the reliability of the battery cell.

[0048] In some embodiments, the first limiting part, the second limiting part, and the terminal body are integrally formed, which can improve the overall structural strength of the electrode terminal, reduce the internal resistance of the electrode terminal, and improve the overcurrent capacity.

[0049] In some embodiments, the battery cell further includes a seal, at least a portion of which is disposed between the first limiting portion and the wall portion. The seal may fill the gap between the first limiting portion and the wall portion to seal the electrode lead-out hole.

[0050] In some embodiments, the melting point of the electrode terminals is lower than that of the wall portion. When a short circuit, overcharge, or other event occurs, the internal temperature of the casing rises rapidly. The lower melting point of the electrode terminals compared to the wall portion allows the electrode terminals to melt or soften before the wall portion, facilitating directional pressure relief of the battery cell.

[0051] In some embodiments, the melting point of the electrode terminal is H1, the melting point of the wall is H2, and H2-H1≥300℃.

[0052] When phenomena such as short circuit or overcharge occur, the internal temperature of the casing is uneven. The above technical solution can make the melting point of the electrode terminals and the melting point of the wall part have a large difference, so as to reduce the risk of the wall part melting before the electrode terminals due to uneven internal temperature and improve the reliability of the battery cell.

[0053] In some embodiments, the electrode terminals are made of aluminum or copper, and the walls are made of steel.

[0054] By using steel as the primary material for the wall section, it gains excellent mechanical strength and high-temperature resistance, reducing the risk of melting and rupture during thermal runaway of the battery cell. The electrode terminals, made of a material with a low melting point, are more prone to softening and deformation during thermal runaway, allowing for timely connection between the internal and external spaces of the casing via electrode lead-out holes, thus reducing the risk of explosion and improving the reliability of the battery cell.

[0055] In some embodiments, the housing includes a housing and an end cap, one end of the housing having an opening and the end cap closing the opening; the housing includes a side wall and an end wall, the side wall surrounding the outside of the electrode assembly, the end wall being disposed opposite to the opening, and the wall portion being an end cap or an end wall.

[0056] The end cap or end wall is flatter than the side wall. By placing the electrode terminals on the end cap or end wall, the assembly efficiency of the battery cell can be improved.

[0057] In some embodiments, the projection of the wall portion along its own thickness direction is rectangular or annular.

[0058] Secondly, this application provides a battery comprising a plurality of battery cells provided in any of the embodiments of the first aspect.

[0059] Thirdly, this application provides an electrical device including the battery provided in the second aspect, the battery being used to provide electrical energy. Attached Figure Description

[0060] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0061] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0062] Figure 2 Explosion diagrams of batteries provided for some embodiments of this application;

[0063] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0064] Figure 4 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0065] Figure 5 for Figure 4 A cross-sectional schematic diagram of a single battery cell is shown.

[0066] Figure 6 for Figure 5 Enlarged view of the area within the circle;

[0067] Figure 7 This is a partial cross-sectional schematic diagram of the casing of a battery cell provided in some embodiments of this application;

[0068] Figure 8 A cross-sectional schematic diagram of the electrode terminals of a battery cell provided in some embodiments of the application;

[0069] Figure 9 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0070] Figure 10 for Figure 9 A schematic diagram of the electrode terminals shown;

[0071] Figure 11 A cross-sectional schematic diagram of the electrode terminals of a battery cell provided in other embodiments of this application;

[0072] Figure 12 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0073] Figure 13 for Figure 12 A cross-sectional schematic diagram of the electrode terminals shown;

[0074] Figure 14 A cross-sectional schematic diagram of the electrode terminals of a battery cell provided in other embodiments of this application;

[0075] Figure 15 A partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application;

[0076] Figure 16 for Figure 15 A cross-sectional schematic diagram of the electrode terminals shown;

[0077] Figure 17 This is a three-dimensional structural diagram of a battery cell provided in some other embodiments of this application.

[0078] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0080] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0081] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0082] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0083] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0084] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0085] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0086] In this application, "multiple" means two or more (including two).

[0087] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0088] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0089] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0090] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0091] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0092] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0093] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.80 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0094] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal may also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0095] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0096] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0097] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0098] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0099] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0100] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0101] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0102] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0103] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0104] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0105] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0106] Liquid electrolytes include electrolyte salts and solvents.

[0107] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0108] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more 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, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0109] Among them, gel electrolytes include a polymer-based electrolyte backbone network combined with an ionic liquid-lithium salt.

[0110] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0111] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0112] As an example, inorganic solid electrolytes can be one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphorus sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0113] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0114] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0115] In some implementations, the electrode assembly is a stacked structure.

[0116] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0117] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0118] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0119] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0120] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0121] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0122] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0123] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0124] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. This application does not have any particular limitations.

[0125] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0126] In some embodiments, the battery can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0127] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0128] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0129] In some embodiments, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0130] In some embodiments, a single battery cell typically includes an electrode assembly, electrode terminals, and a housing. The electrode assembly is electrically connected to the outside via the electrode terminals. The housing accommodates the electrode assembly and provides support for it.

[0131] When short circuits or overcharging occur, thermal runaway may occur inside the battery cell, causing a sudden increase in internal pressure of the casing, which may lead to the risk of the battery cell exploding.

[0132] Based on the above considerations, this application provides a battery cell that, when the internal pressure or temperature of the casing reaches a threshold, utilizes the deformation of the electrode terminals to connect the internal space of the casing with the external space, thereby releasing the internal pressure of the battery cell and reducing the risk of battery cell explosion. Compared to solutions that additionally set pressure relief mechanisms on the casing, this application simplifies the structure of the battery cell.

[0133] The battery cells described in the embodiments of this application are applicable to batteries and electrical devices that use batteries.

[0134] The battery cell, battery, and electrical device disclosed in this application can be used in electrical devices that use batteries as a power source or in various energy storage systems that use batteries as energy storage elements. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., while spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0135] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0136] Figure 1 The diagram shows the structure of a vehicle provided in some embodiments of this application.

[0137] like Figure 1 As shown, a battery 2 is installed inside the vehicle 1. The battery 2 can be located at the bottom, front, or rear of the vehicle 1. The battery 2 can be used to power the vehicle 1; for example, the battery 2 can serve as the operating power source for the vehicle 1.

[0138] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0139] In some embodiments of this application, the battery 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0140] Figure 2 This is a schematic diagram of a battery explosion provided for some embodiments of this application. For example... Figure 2 As shown, battery 2 includes a housing 5 and battery cells ( Figure 2 (Not shown), the battery cells are housed inside the casing 5.

[0141] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0142] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0143] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0144] In battery 2, there can be one or more individual battery cells. If there are multiple individual battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple individual battery cells are connected in both series and parallel configurations. Multiple individual battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed within housing 5. Alternatively, multiple individual battery cells can first be connected in series, parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed configuration to form a whole and housed within housing 5.

[0145] A single battery cell can be the smallest unit that makes up a battery.

[0146] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0147] In some embodiments, such as Figure 3As shown, there are multiple battery cells 7, which are first connected in series, parallel, or a combination of both to form a battery module 6. These battery modules 6 are then connected in series, parallel, or a combination of both to form a whole, which is housed within the casing.

[0148] Multiple battery cells 7 in battery module 6 can be electrically connected through busbars to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6. There can be one or more busbars, each used to electrically connect at least two battery cells.

[0149] Figure 4 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application; Figure 5 for Figure 4 A cross-sectional schematic diagram of a single battery cell is shown. Figure 6 for Figure 5 Enlarged view of the area within the circle; Figure 7 This is a partial cross-sectional schematic diagram of the casing of a battery cell provided in some embodiments of this application; Figure 8 This is a cross-sectional schematic diagram of the electrode terminals of a battery cell provided in some embodiments of the application.

[0150] like Figures 4 to 8 As shown, this application provides a battery cell 7, which includes a housing 20, an electrode assembly 10, and other functional components (such as electrode terminals 30 disposed on the housing 20), at least a portion of the electrode assembly 10 being housed within the housing 20.

[0151] The outer shell 20 is a hollow structure, forming an internal space for accommodating the electrode assembly 10 and the electrolyte. The shape of the outer shell 20 can be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 is a cuboid structure, a cuboid outer shell can be used; if the electrode assembly 10 is a cylindrical structure, a cylindrical outer shell can be used.

[0152] As an example, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening and the end cap 22 for closing the opening.

[0153] The housing 21 is a component used to fit the end cap 22 to form the internal cavity of the battery cell 7. The formed internal cavity can be used to accommodate the electrode assembly 10, the electrolyte, and other components.

[0154] The housing 21 and the end cap 22 can be separate components. For example, an opening can be provided on the housing 21, and the end cap 22 can be used to close the opening to form an internal cavity for the battery cell 7.

[0155] The housing 21 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode assembly 10. The material of the housing 21 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and this application embodiment does not impose any special limitations on this.

[0156] The shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21. The material of the end cap 22 can be the same as or different from the material of the housing 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.), so that the end cap 22 is not easily deformed when subjected to compression and impact, so that the battery cell 7 can have higher structural strength and improve reliability.

[0157] The end cap 22 is connected to the housing 21 by welding, bonding, snap-fitting or other means.

[0158] The housing 21 may be open at one end or open at both ends. In some examples, the housing 21 may be a structure with an opening on one side, and one end cap 22 is provided to cover the housing 21. In other examples, the housing 21 may also be a structure with openings on both sides, and two end caps 22 are provided, with the two end caps 22 respectively covering the two openings of the housing 21.

[0159] The electrode terminal 30 can be used to electrically connect to the electrode assembly 10 for outputting or inputting electrical energy into the battery cell 7.

[0160] Electrode assembly 10 is a component in the battery cell 7 where electrochemical reactions occur. The housing 21 may contain one or more electrode assemblies 10.

[0161] As an example, the electrode assembly 10 includes a positive electrode and a negative electrode. The portions of the positive and negative electrode having active material constitute the main body of the electrode assembly 10, and the portions of the positive and negative electrode without active material each constitute a tab. The tab may include a positive tab and a negative tab. The positive and negative tabs may be located together at one end of the main body or at opposite ends of the main body.

[0162] During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals 30 to form a current loop.

[0163] In some embodiments, the battery cell 7 includes a housing 20, an electrode assembly 10, and electrode terminals 30. The housing 20 includes a wall 23 with an electrode lead-out hole 231. At least a portion of the electrode assembly 10 is housed within the housing 20, and the electrode assembly 10 includes tabs 11. The electrode terminals 30 are disposed on the wall 23 and cover at least a portion of the electrode lead-out hole 231, and are electrically connected to the tabs 11. At least a portion of the electrode terminals 30 can deform when the internal pressure or temperature of the housing 20 reaches a threshold, so that the internal space of the housing 20 communicates with the external space through the electrode lead-out hole 231, and allows gas inside the housing 20 to escape.

[0164] As an example, wall 23 can be end cap 22 or a wall of housing 21.

[0165] As an example, the shape of the wall portion 23 can be circular, rectangular, elliptical, or other shapes.

[0166] For example, the electrode lead-out hole 231 extends through the wall portion 23 so that the electrode terminal 30 can lead the electrical energy of the electrode assembly 10 to the outside of the housing 20. Alternatively, the electrode lead-out hole 231 extends through the wall portion 23 along the thickness direction Z of the wall portion 23.

[0167] The tab 11 electrically connected to the electrode terminal 30 can be either a positive tab or a negative tab.

[0168] The tab 11 can be directly connected to the electrode terminal 30, for example, by welding, abutting or other means. Alternatively, the tab 11 can also be indirectly connected to the electrode terminal 30 through other conductive components (e.g., current collector 40) to achieve electrical connection between the tab 11 and the electrode terminal 30.

[0169] The material of the electrode terminal 30 can be the same as or different from the material of the wall portion 23. As an example, the electrode terminal 30 and the wall portion 23 can be made of different materials, and the melting point of the electrode terminal 30 can be the same as or different from the melting point of the wall portion 23.

[0170] The electrode terminal 30 may cover only a portion of the electrode lead-out hole 231 or it may completely cover the electrode lead-out hole 231. As an example, the electrode terminal 30 may alone close the electrode lead-out hole 231 to isolate the internal space of the housing 20 from the external space and improve the sealing performance of the battery cell 7; alternatively, the electrode terminal 30 may also cooperate with other functional components (such as the seal 50) to jointly close the electrode lead-out hole 231 to isolate the internal space of the housing 20 from the external space and improve the sealing performance of the battery cell 7.

[0171] The threshold design varies depending on the design requirements. The threshold may depend on the materials of one or more of the positive electrode, negative electrode, electrolyte, and separator in the battery cell 7.

[0172] When the internal pressure or temperature of the housing 20 reaches a threshold, the deformation of the electrode terminal 30 includes, but is not limited to: bending, cracking, shrinkage, melting, etc.

[0173] When phenomena such as short circuit or overcharge occur, the electrolyte and active material react and release gas and heat.

[0174] In this embodiment, the deformation of the electrode terminal 30 may be triggered by the internal pressure of the housing 20 alone, or by the internal temperature of the housing 20 alone, or by a combination of the internal pressure and internal temperature of the housing 20.

[0175] As an example, as gas accumulates inside the casing 20, the internal pressure of the casing 20 may reach or even exceed a pressure threshold. When the internal pressure of the casing 20 reaches the threshold, the electrode terminal 30 deforms under the action of the internal pressure, so that the internal space of the casing 20 is connected to the external space through the electrode lead-out hole 231. The gas inside the casing 20 can be discharged through the electrode lead-out hole 231, thereby reducing the risk of battery cell 7 explosion.

[0176] As an example, when the electrolyte and active material react and rapidly release heat, the internal temperature of the casing 20 will rise, which will also cause the internal pressure of the casing 20 to rise. When the internal temperature of the casing 20 reaches a threshold, the electrode terminal 30 can deform under the action of temperature and pressure, so that the internal space of the casing 20 is connected to the external space through the electrode lead-out hole 231. The gas inside the casing 20 can be discharged through the electrode lead-out hole 231, thereby reducing the risk of the battery cell 7 exploding.

[0177] When the internal pressure or temperature of the casing 20 reaches a threshold, this embodiment of the application can utilize the deformation of the electrode terminals 30 to connect the internal space of the casing 20 with the external space, thereby releasing the internal gas and internal pressure of the casing 20 and reducing the risk of the battery cell 7 exploding. Compared to the solution of additionally setting a pressure relief mechanism on the casing 20, this embodiment of the application can also simplify the structure of the battery cell 7 and reduce the cost of the battery cell.

[0178] In some embodiments, at least a portion of the electrode terminal 30 may detach from the wall portion 23 when the internal pressure or temperature of the housing 20 reaches a threshold.

[0179] When the internal pressure or temperature of the housing 20 reaches a threshold, the electrode terminal 30 may be completely detached from the wall 23, or only partially detached from the wall 23.

[0180] At least a portion of the electrode terminal 30 is detached from the wall portion 23, which means that at least a portion of the electrode terminal 30 is no longer bound by the wall portion 23 and can deviate from the initial set position.

[0181] When at least a portion of the electrode terminal 30 detaches from the wall portion 23, at least a portion of the electrode lead-out hole 231 is no longer covered by the electrode terminal 30. The electrode lead-out hole 231 can connect the internal space and the external space of the housing 20, thereby releasing the internal gas of the battery cell 7 and reducing the internal pressure and temperature of the battery cell 7.

[0182] In some embodiments, the electrode terminal 30 can be completely detached from the wall portion 23 when the internal pressure or temperature of the housing 20 reaches a threshold.

[0183] When a short circuit or overcharge occurs, the electrode terminal 30 can detach from the wall 23 so that the electrode lead hole 231 is no longer blocked by the electrode terminal 30, thereby increasing the gas release rate and reducing the risk of battery cell 7 explosion.

[0184] In some embodiments, the housing 20 includes a housing 21 and an end cap 22, one end of the housing 21 having an opening, and the end cap 22 covering the opening. The housing 21 includes a side wall 212 and an end wall 211, the side wall 212 surrounding the outside of the electrode assembly 10, the end wall 211 being disposed opposite to the opening, and the wall portion 23 being either the end cap 22 or the end wall 211.

[0185] There may be one or more sidewalls 212. In some examples, there may be one sidewall 212 and it may be a cylindrical structure. In other examples, there may be multiple sidewalls 212 and they may be connected sequentially along the circumference of the electrode assembly 10; for example, there may be four sidewalls 212, which may be connected sequentially to form a rectangular structure.

[0186] In some embodiments, the battery cell 7 is a cylindrical battery cell with a single sidewall 212 in a cylindrical structure. Since the end cap 22 or end wall 211 is flatter than the sidewall 212, the assembly efficiency of the battery cell 7 can be improved by placing the electrode terminal 30 on the end cap 22 or end wall 211.

[0187] In some embodiments, the housing 21 is an integrally formed structure, and the wall portion 23 is an end wall 211.

[0188] In some embodiments, the melting point of the electrode terminal 30 is lower than the melting point of the wall portion 23.

[0189] When a short circuit or overcharge occurs, the internal temperature of the casing 20 will rise rapidly. The electrode terminal 30 has a lower melting point than the wall portion 23, which allows the electrode terminal 30 to melt or soften before the wall portion 23, thus facilitating directional pressure relief of the battery cell 7.

[0190] In addition, when welding the electrode terminal 30 to other components, the lower melting point of the electrode terminal 30 material helps to reduce the welding temperature, while the relatively higher melting point of the wall 23 material can reduce the adverse effects of the welding process on the wall 23, thereby reducing the risk of electrolyte leakage.

[0191] In some embodiments, the melting point of the electrode terminal 30 is H1, and the melting point of the wall portion 23 is H2, with H2-H1 ≥ 300°C.

[0192] When a short circuit or overcharge occurs, the internal temperature of the casing 20 is uneven. In this embodiment, the melting point of the electrode terminal 30 and the melting point of the wall 23 can be significantly different, so as to reduce the risk that the wall 23 melts before the electrode terminal 30 due to uneven internal temperature and improve the reliability of the battery cell 7.

[0193] Optionally, H2-H1 ≥ 500℃.

[0194] In some embodiments, the electrode terminal 30 is made of aluminum or copper, and the wall portion 23 is made of steel. As an example, the wall portion 23 may be made of stainless steel, nickel-plated steel, or other steel-based materials.

[0195] By using steel as the primary material for the wall portion 23, it gains excellent mechanical strength and high-temperature resistance, reducing the risk of melting and rupture during thermal runaway of the battery cell 7. The electrode terminals 30 are made of a material with a low melting point, making them more prone to softening and deformation during thermal runaway of the battery cell 7. This allows for timely communication between the internal and external spaces of the casing 20 via the electrode lead-out holes 231, reducing the risk of explosion and improving the reliability of the battery cell 7.

[0196] In some embodiments, the battery cell 7 further includes a current collector 40, which connects the electrode terminal 30 and the tab 11. Optionally, when the internal pressure or temperature of the housing 20 reaches a threshold, the electrode terminal 30 is disconnected from the current collector 40 and detached from the wall 23.

[0197] In some embodiments, the current collector 40 can be connected to the tab 11 by welding, abutting, bonding or other means, and connected to the electrode terminal 30 by welding, abutting, bonding or other means, so as to realize the electrical connection between the electrode terminal 30 and the tab 11.

[0198] The current collector 40 is made of a conductive material, for example, the current collector 40 is made of a conductive metal.

[0199] In some embodiments, the surface of the current collector 40 facing away from the wall portion 23 abuts against the tab 11, and the surface of the current collector 40 facing the wall portion 23 abuts against the electrode terminal 30.

[0200] In some embodiments, the current collector 40 is welded to the tab 11. As an example, the current collector 40 is connected to the tab 11 by ultrasonic welding, laser welding or other welding methods.

[0201] In some embodiments, the main material of the current collector 40 is the same as the main material of the tab 11.

[0202] In some examples, the main material of the current collector 40 is aluminum, and the main material of the tab 11 is aluminum; for example, the current collector 40 is made of aluminum alloy, and the tab 11 is made of aluminum foil.

[0203] In other examples, the main material of the current collector 40 is copper, and the main material of the tab 11 is copper; for example, the current collector 40 is made of copper alloy, and the tab 11 is made of copper foil. Having the same main material for both the current collector 40 and the tab 11 can improve the welding strength between them, reduce resistance, and increase current carrying capacity.

[0204] In some embodiments, the current collector 40 is welded to the electrode terminal 30. As an example, the current collector 40 is connected to the electrode terminal 30 by laser welding, resistance welding, ultrasonic torque welding or other welding methods.

[0205] In some embodiments, the main material of the current collector 40 is the same as the main material of the electrode terminal 30.

[0206] In some examples, the main material of the current collector 40 is aluminum, and the main material of the electrode terminal 30 is aluminum; for example, both the electrode terminal 30 and the current collector 40 are made of aluminum alloy.

[0207] In other examples, the main material of the current collector 40 is copper, and the main material of the electrode terminal 30 is copper; for example, both the electrode terminal 30 and the current collector 40 are made of copper alloy.

[0208] In some embodiments, when the internal temperature of the housing 20 reaches a threshold, the strength of the solder joint between the electrode terminal 30 and the current collector 40 decreases, and under the action of the internal pressure of the housing 20, the electrode terminal 30 and the current collector 40 tear, so as to release the current collector 40 from the electrode terminal 30 and allow the electrode terminal 30 to detach from the wall portion 23.

[0209] In some embodiments, when the internal pressure or temperature of the housing 20 reaches a threshold, the solder joint between the electrode terminal 30 and the current collector 40 tears, while the solder joint between the tab 11 and the current collector 40 maintains a fixed connection between the tab 11 and the current collector 40, thereby reducing the risk of the current collector 40 blocking the electrode lead-out hole 231.

[0210] In some embodiments, the electrode terminal 30 includes a protrusion 311 that protrudes radially from the wall 231a of the electrode lead-out hole 231, the protrusion 311 being located on the side of the wall 23 facing the electrode assembly 10.

[0211] The radial direction of the electrode lead-out hole 231 can be a direction passing through the central axis X of the electrode lead-out hole 231 and perpendicular to the central axis X of the electrode lead-out hole 231. Optionally, the central axis X of the electrode lead-out hole 231 is parallel to the thickness direction Z of the wall portion 23.

[0212] The central axis X of the electrode lead-out hole 231 is a single, virtual line. As an example, the electrode lead-out hole 231 is rotationally symmetrical about the central axis.

[0213] In some examples, the electrode lead-out hole 231 may be a circular hole, and the radial direction of the electrode lead-out hole 231 may be the radius direction of the electrode lead-out hole 231; in other examples, the electrode lead-out hole 231 may be a square hole, and the radial direction of the electrode lead-out hole 231 may be the radius direction of the circumcircle of the electrode lead-out hole 231.

[0214] The protrusion 311 protrudes from the wall 231a of the electrode lead-out hole 231, which can mean that the projection of the protrusion 311 does not overlap with the projection of the electrode lead-out hole 231 in the thickness direction Z of the wall 23.

[0215] There may be one or more protrusions 311. In some examples, there is one protrusion 311 and it is annular; in other examples, there are multiple protrusions 311, which are spaced apart circumferentially along the electrode lead-out hole 231.

[0216] During normal operation of the battery cell 7, the wall portion 23 can stop the protrusion 311 to reduce the risk of the electrode terminal 30 coming out of the electrode lead hole 231.

[0217] In some embodiments, the protrusion 311 can deform when the internal pressure or temperature of the housing 20 reaches a threshold.

[0218] The deformation of the protrusion 311 includes, but is not limited to, fracture, bending, melting, etc.

[0219] When the internal pressure or temperature of the housing 20 reaches a threshold, the protrusion 311 can deform so that the wall 23 no longer blocks the protrusion 311, and the electrode terminal 30 can be dislodged from the electrode lead-out hole 231, thereby connecting the internal space of the housing 20 with the external space through the electrode lead-out hole 231. The gas inside the housing 20 can be discharged through the electrode lead-out hole 231, thereby reducing the risk of battery cell 7 explosion.

[0220] For example, when the internal pressure or temperature of the housing 20 reaches a threshold, the electrode terminal 30 moves outward through the electrode lead-out hole 231 under the action of the internal pressure; during the movement of the electrode terminal 30, the protrusion 311 folds and deforms under the resistance of the wall portion 23 so that the protrusion 311 can pass through the electrode lead-out hole 231.

[0221] In some embodiments, the maximum dimension of the protrusion 311 protruding from the wall 231a of the electrode lead-out hole 231 is L1, and the minimum distance between the periphery 23a of the wall 23 and the wall 231a of the electrode lead-out hole 231 is L2. L1 and L2 satisfy: 0.1≤L1 / L2≤0.5.

[0222] As an example, L1 can be the maximum dimension by which the protrusion 311 protrudes beyond the wall 231a of the electrode lead-out hole 231 in the radial direction. As an example, L2 can be the minimum distance between the periphery 23a of the wall portion 23 and the wall 231a of the electrode lead-out hole 231 in the radial direction.

[0223] As an example, when the wall portion 23 is an end cap 22, the periphery 23a of the wall portion 23 can be the outer periphery of the end cap 22; when the wall portion 23 is an end wall 211, the periphery 23a of the wall portion 23 can be the connection between the end wall 211 and the side wall 212.

[0224] The value of L1 / L2 is positively correlated with the area of ​​the protrusion 311 blocked by the wall 23; the larger L1 / L2 is, the more difficult it is for the protrusion 311 to deform under the action of internal pressure; the smaller L1 / L2 is, the lower the stability of the electrode terminal 30 on the wall 23.

[0225] In this embodiment, the value of L1 / L2 is limited to less than or equal to 0.5, which allows for timely deformation when the internal pressure or temperature of the casing 20 reaches a threshold, thereby improving the reliability of the battery cell 7. In another embodiment, the value of L1 / L2 is limited to greater than or equal to 0.1, which improves the stability of the electrode terminals 30 on the wall 23 and reduces the risk of the electrode terminals 30 detaching when the battery cell 7 is subjected to external impact.

[0226] Optionally, the value of L1 / L2 is 0.1, 0.2, 0.3, 0.4 or 0.5.

[0227] Optionally, the value of L1 / L2 is 0.2-0.3.

[0228] In some embodiments, the maximum dimension of the wall 231a of the protrusion 311 protruding from the electrode lead-out hole 231 is L1, and the maximum thickness of the protrusion 311 is T1. L1 and T1 satisfy: 0.25mm 2 ≤L1×T1≤25mm2 .

[0229] Both L1 and T1 affect the difficulty of deforming the protrusion 311. The larger L1 is, the higher the strength of the protrusion 311, and the more difficult it is to deform the protrusion 311; similarly, the larger T1 is, the higher the strength of the protrusion 311, and the more difficult it is to deform the protrusion 311.

[0230] In this embodiment, the value of L1×T1 is limited to less than or equal to 25mm. 2 This allows for timely deformation of the battery cell 7 when the internal pressure or temperature of the outer casing 20 reaches a threshold, improving the reliability of the battery cell 7. In this embodiment, the value of L1×T1 is defined as greater than or equal to 0.25 mm. 2 This can improve the stability of the electrode terminal 30 on the wall 23 and reduce the risk of the electrode terminal 30 falling off when the battery cell 7 is subjected to external impact.

[0231] Optionally, the value of L1×T1 is 0.25mm. 2 0.5mm 2 1mm 2 5mm 2 8mm 2 10mm 2 15mm 2 20mm 2 Or 25mm 2 .

[0232] Optionally, the value of L1×T1 is 1 mm. 2 ≤L1×T1≤5mm 2 .

[0233] In some embodiments, T1 is 0.5mm-5mm. As an example, T1 is 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 4mm or 5mm.

[0234] In this embodiment, T1 is limited to 0.5mm-5mm, which allows for timely deformation when the internal pressure or temperature of the casing 20 reaches a threshold, and reduces the risk of the electrode terminal 30 falling off when the battery cell 7 is subjected to external impact.

[0235] In some embodiments, L1 is 0.5mm-5mm. As an example, L1 is 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 4mm or 5mm.

[0236] In some embodiments, the direction from the central axis X of the electrode lead-out hole 231 to the outer periphery 311a of the protrusion 311 is such that the thickness of at least a portion of the protrusion 311 gradually decreases.

[0237] The protrusion 311 includes a variable thickness region with gradually decreasing thickness. The thickness of the variable thickness region is greatest at the end near the central axis X of the electrode lead hole 231, and smallest at the end near the outer periphery 311a of the protrusion 311.

[0238] By providing a variable thickness region with gradually decreasing thickness on the protrusion 311, this application makes it easier for the protrusion 311 to deform under internal pressure, thereby releasing pressure in time and improving the reliability of the battery cell 7.

[0239] In some embodiments, the protrusion 311 has a first surface 311b facing the wall portion 23, the wall portion 23 has a second surface 232 facing the protrusion 311, the second surface 232 is perpendicular to the thickness direction Z of the wall portion 23, and the first surface 311b is inclined relative to the second surface 232 toward the electrode assembly 10.

[0240] For example, in the thickness direction Z of the wall portion 23, the distance between the end of the first surface 311b away from the electrode lead-out hole 231 and the second surface 232 is greater than the distance between the end of the first surface 311b near the electrode lead-out hole 231 and the second surface 232.

[0241] When the internal pressure or temperature of the housing 20 reaches a threshold, the inclined first surface 311b can guide the deformation of the protrusion 311, making it easier for the protrusion 311 to pass through the electrode lead hole 231, thereby releasing pressure in time and improving the reliability of the battery cell 7.

[0242] In some embodiments, the protrusion 311 has a third surface 311c facing away from the wall portion 23, and the third surface 311c is parallel to the second surface 232. The thickness of the protrusion 311 gradually decreases in the direction from the central axis X of the electrode lead-out hole 231 to the outer periphery 311a of the protrusion 311.

[0243] In some embodiments, the electrode terminal 30 includes a terminal body 32 and a first limiting portion 31 connected to each other. At least a portion of the terminal body 32 is received in the electrode lead-out hole 231. The first limiting portion 31 is located on the side of the wall portion 23 facing the electrode assembly 10 and protrudes from the outer peripheral surface 321 of the terminal body 32. The first limiting portion 31 includes a protrusion 311.

[0244] The first limiting part 31 may include only the protrusion 311, or it may include other parts besides the protrusion 311.

[0245] There may be one or more first limiting parts 31. Optionally, there may be one first limiting part 31, and the first limiting part 31 may be a ring structure.

[0246] By configuring the terminal body 32 to extend into the electrode lead-out hole 231, it is easy to connect the electrode terminal 30 to other components outside the battery cell 7. The wall portion 23 forms a block against the protrusion 311, thereby preventing the electrode terminal 30 from detaching from the inside of the housing 20.

[0247] In some embodiments, the electrode terminal 30 further includes a second limiting portion 33, which protrudes from the outer peripheral surface 321 of the terminal body 32 and is disposed on the outer side of the wall portion 23. In the thickness direction Z of the wall portion 23, at least a portion of the wall portion 23 is located between the protrusion 311 and the second limiting portion 33.

[0248] The wall portion 23 may be positioned between the first limiting portion 31 and the second limiting portion 33 to restrict the relative movement between the electrode terminal 30 and the wall portion 23.

[0249] In some embodiments, in the radial direction of the electrode lead-out hole 231, the end of the second limiting portion 33 away from the terminal body 32 extends beyond the end of the first limiting portion 31 away from the terminal body 32.

[0250] In the radial direction of the electrode lead-out hole 231, the second limiting portion 33 has a larger size than the first limiting portion 31. This increases the exposed area of ​​the electrode terminal 30, facilitating connection between the electrode terminal 30 and external busbar components, increasing the connection area between the electrode terminal 30 and the busbar component, and improving the current carrying capacity. In the radial direction of the electrode lead-out hole 231, the first limiting portion 31 has a larger size than the second limiting portion 33, making it more prone to deformation when the internal pressure or temperature of the casing 20 reaches a threshold, thereby allowing for timely pressure relief and improving the reliability of the battery cell 7.

[0251] In some embodiments, the first limiting part 31, the second limiting part 33, and the terminal body 32 are integrally formed. The embodiments of this application can improve the overall structural strength of the electrode terminal 30, reduce the internal resistance of the electrode terminal 30, and improve its overcurrent capacity.

[0252] In some embodiments, the battery cell 7 further includes a seal 50, at least a portion of which is disposed between the first limiting portion 31 and the wall portion 23.

[0253] As an example, the electrode terminal 30 and the seal 50 together separate the internal space and the external space of the housing 20 to improve the sealing of the battery cell 7.

[0254] The seal 50 can fill the gap between the first limiting part 31 and the wall part 23 to seal the electrode lead-out hole 231.

[0255] In some embodiments, the portion of the seal 50 sandwiched between the first limiting portion 31 and the wall portion 23 is compressed to seal the electrode lead-out hole 231.

[0256] In some embodiments, a portion of the seal 50 is disposed between the second limiting portion 33 and the wall portion 23.

[0257] In some embodiments, a portion of the seal 50 is disposed in the electrode lead-out hole 231 and separates the hole wall 231a of the electrode lead-out hole 231 from the terminal body 32.

[0258] In some embodiments, the seal 50 is made of an insulating material. The seal 50 can insulate the wall portion 23 from the electrode terminal 30.

[0259] In some embodiments, the battery cell 7 further includes an insulating member 60 disposed on the surface of the wall 23 facing the electrode assembly 10. The insulating member 60 can be used to insulate at least a portion of the electrode assembly 10 from the wall 23.

[0260] In some embodiments, the projection of the wall portion 23 along its thickness direction Z is annular. Optionally, the battery cell 7 is a cylindrical battery cell.

[0261] Figure 9 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of this application; Figure 10 for Figure 9 A schematic diagram of the electrode terminals is shown.

[0262] like Figure 9 and Figure 10 As shown, in some embodiments, the first limiting part 31 is provided with a weak part 313, and the first limiting part 31 can be bent or broken along the weak part 313 when the internal pressure or temperature of the outer shell 20 reaches a threshold.

[0263] The weak portion 313 is the part of the first limiting portion 31 with relatively low strength, and it is the part of the first limiting portion 31 that is prone to breakage or bending. For example, the strength of the weak portion 313 is less than the strength of the portion of the first limiting portion 31 near the weak portion 313.

[0264] In some examples, this application may create grooves, grooves, through holes, or other structures in a predetermined area of ​​the first limiting portion 31 to reduce the local strength of the first limiting portion 31, thereby forming a weak portion 313 on the first limiting portion 31. For example, a thinning process may be performed on a predetermined area of ​​the first limiting portion 31, and the thinned portion of the first limiting portion 31 forms the weak portion 313. In other examples, a material treatment may be performed on a predetermined area of ​​the first limiting portion 31 to make the strength of this area weaker than the strength of other areas; in other words, this area is the weak portion 313.

[0265] As an example, the weak portion 313 may be entirely provided on the protrusion 311, or it may be only partially provided on the protrusion 311. In an alternative example, the weak portion 313 may be entirely provided on the portion of the first limiting portion 31 other than the protrusion 311.

[0266] By providing a weak part 313 on the first limiting part 31, the difficulty of deformation of the first limiting part 31 can be reduced when the internal pressure or temperature of the outer casing 20 reaches a threshold, so that the first limiting part 31 can be bent or broken at a preset position, thereby allowing the internal space of the outer casing 20 to be connected to the external space through the electrode lead-out hole 231, reducing the risk of battery cell 7 explosion.

[0267] In some embodiments, at least a portion of the projection of the weak portion 313 onto the thickness direction Z of the wall portion 23 lies within the electrode lead-out hole 231.

[0268] The projection of the weak part 313 in the thickness direction Z overlaps at least partially with the projection of the electrode lead-out hole 231 in the thickness direction Z.

[0269] In this embodiment, when the internal pressure or temperature of the outer casing 20 reaches a threshold, the bend of the first limiting part 31 can be brought closer to the electrode lead-out hole 231, thereby making it easier for the first limiting part 31 to pass through the electrode lead-out hole 231.

[0270] In some embodiments, the first limiting portion 31 includes a protrusion 311 and a connecting portion 312. The connecting portion 312 is used to connect the protrusion 311 and the terminal body 32. The projection of the connecting portion 312 in the thickness direction Z of the wall portion 23 is located between the outer peripheral surface 321 of the terminal body 32 and the hole wall 231a of the electrode lead-out hole 231. A weak portion 313 is provided in the connecting portion 312.

[0271] In some examples, a portion of the connection 312 is a weak portion 313; in alternative embodiments, the entire connection 312 is a weak portion 313.

[0272] The projection of the weak part 313 in the thickness direction Z of the wall part 23 is entirely located within the electrode lead-out hole 231.

[0273] For example, when the internal pressure or temperature of the housing 20 reaches a threshold, the protrusion 311 can be flipped as the weak portion 313 bends to avoid the wall portion 23 and pass through the electrode lead-out hole 231. By providing the weak portion 313 in the connecting portion 312 in this embodiment, the limitation on the strength of the protrusion 311 can be reduced, and the shape design of the protrusion 311 can be more flexible.

[0274] For example, when the internal pressure or temperature of the housing 20 reaches a threshold, the first limiting part 31 can break along the weak part 313 so that the wall part 23 no longer binds the terminal body 32 through the protrusion 311, thereby allowing the terminal body 32 to pass through the electrode lead-out hole 231.

[0275] In some embodiments, the electrode terminal 30 is provided with a groove 314, and a weak portion 313 is formed at the bottom of the groove 314. By forming the weak portion 313 by providing a groove 314, the forming efficiency of the electrode terminal 30 can be improved.

[0276] In some embodiments, the groove 314 is provided on the surface of the first limiting portion 31 away from the wall portion 23.

[0277] When the internal pressure or temperature of the outer casing 20 reaches a threshold, the groove 314 can provide space for the flow of material, which helps to achieve the bending of the first limiting part 31.

[0278] Figure 11 This is a cross-sectional schematic diagram of the electrode terminals of a battery cell provided in some other embodiments of this application.

[0279] like Figure 11 As shown, in some embodiments, the groove 314 is provided on the surface of the first limiting portion 31 facing the wall portion 23.

[0280] In some embodiments, the surface of the first limiting portion 31 facing away from the wall portion 23 abuts against the current collecting member 40. By providing a groove 314 on the surface of the first limiting portion 31 facing the wall portion 23, the influence of the groove 314 on the contact area between the first limiting portion 31 and the current collecting member 40 can be reduced, thereby improving the flow capacity.

[0281] In some embodiments, a portion of the seal 50 is filled within the groove 314.

[0282] In some embodiments, the surface of the first limiting portion 31 facing the wall portion 23 is provided with a groove 314, and the surface of the first limiting portion 31 away from the wall portion 23 is also provided with a groove 314, and a weak portion 313 is formed between the two grooves 314.

[0283] Figure 12 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of this application; Figure 13 for Figure 12 The diagram shows a cross-sectional view of the electrode terminals.

[0284] like Figure 12 and Figure 13As shown, in some embodiments, the electrode terminal 30 is provided with a recess 34. Along the thickness direction Z of the wall portion 23, the recess 34 is recessed from the inside of the housing 20 toward the outside of the housing 20. At least a portion of the recess 34 is provided on the side of the terminal body 32 facing the tab 11.

[0285] When the internal pressure or temperature of the outer shell 20 reaches a threshold, the first limiting part 31 bends; the recess 34 can provide space for the flow of material during the bending process of the first limiting part 31, thereby reducing the resistance of the bending of the first limiting part 31 and enabling the first limiting part 31 to pass through the electrode lead-out hole 231 in time.

[0286] In some embodiments, the recess 34 includes a first side surface 341 and a second side surface 342. The first side surface 341 is disposed on the outer side of the second side surface 342 along the radial direction of the electrode lead-out hole 231. The first side surface 341 is connected to the bottom surface 343 of the recess 34 and is inclined toward the side away from the central axis Y of the electrode terminal 30.

[0287] For example, the first side 341 being located outside the second side 342 can mean that, along the radial direction of the electrode lead-out hole 231, the first side 341 is located on the side of the second side 342 away from the central axis Y of the electrode terminal 30.

[0288] The bottom surface 343 of the recess 34 can be a plane or a curved surface. For example, the first side surface 341 and the second side surface 342 are respectively connected to the two ends of the bottom surface 343.

[0289] For example, the central axis Y of the electrode terminal 30 may be parallel to the central axis X of the electrode lead-out hole 231.

[0290] Optionally, the central axis Y of the electrode terminal 30 may coincide with the central axis X of the electrode lead-out hole 231. Of course, due to process errors, the central axis Y of the electrode terminal 30 may also deviate from the central axis X of the electrode lead-out hole 231 by a certain distance.

[0291] By tilting the first side 341, more space can be provided for the flow of material when the first limiting part 31 is bent, thus reducing the resistance to bending of the first limiting part 31.

[0292] In some embodiments, the recess 34 includes a first side surface 341 and a second side surface 342. The first side surface 341 is disposed on the outer side of the second side surface 342 along the radial direction of the electrode lead-out hole 231. The second side surface 342 is connected to the bottom surface 343 of the recess 34 and is inclined toward the side close to the central axis Y of the electrode terminal 30.

[0293] By tilting the second side 342, the risk of interference between the second side 342 and the first side 341 can be reduced when the first side 341 deforms due to material flow, and the resistance to bending of the first limiting part 31 can be reduced.

[0294] In some embodiments, a first side surface 341 is connected to the bottom surface 343 of the recess 34 and is inclined toward the side away from the central axis Y of the electrode terminal 30, and a second side surface 342 is connected to the bottom surface 343 of the recess 34 and is inclined toward the side close to the central axis Y of the electrode terminal 30.

[0295] In some embodiments, the first limiting portion 31 can be bent toward the recess 34 when the internal pressure or temperature of the housing 20 reaches a threshold.

[0296] When the internal pressure or temperature of the outer casing 20 reaches a threshold, the first limiting part 31 bends toward the recess 34 so that the material flows toward the recess 34, reducing the resistance of the bending of the first limiting part 31, and allowing the first limiting part 31 to pass through the electrode lead-out hole 231 in time.

[0297] In some embodiments, the first limiting portion 31 is formed by folding a portion of the electrode terminal 30.

[0298] During assembly, the electrode terminal 30 can be inserted into the interior of the housing 20 through the electrode lead-out hole 231, and then a part of the electrode terminal 30 can be folded over to form the first limiting part 31, thereby fixing the electrode terminal 30 to the wall part 23.

[0299] In some embodiments, when the electrode terminal 30 extends into the interior of the housing 20 from the outside through the electrode lead-out hole 231, the electrode terminal 30 can be squeezed from the inside to bend a portion of the electrode terminal 30 and form a flange-shaped first limiting portion 31.

[0300] A recess 34 may be formed in the part of the electrode terminal 30 that is pressed by an external workpiece.

[0301] In some embodiments, the terminal body 32 includes a terminal protrusion 322, and a recess 34 is disposed around the terminal protrusion 322. In the thickness direction Z of the wall portion 23, the end face 322a of the terminal protrusion 322 facing the tab 11 is closer to the tab 11 than the first limiting portion 31.

[0302] In this embodiment, the first limiting part 31 is less likely to interfere with the contact between the terminal protrusion 322 and other components (such as the tab 11 or the current collector 40), thereby reducing over-positioning, reducing the risk of poor contact between the terminal protrusion 322 and other components due to the unevenness of the first limiting part 31, and improving the overcurrent capacity and reliability of the battery cell 7.

[0303] Figure 14 A cross-sectional schematic diagram of the electrode terminals of a battery cell provided in other embodiments of this application;

[0304] like Figure 14 As shown, in some embodiments, the terminal body 32 has a recess 34 on the side facing the tab 11, and the first limiting part 31 has a weak part 313.

[0305] By simultaneously providing the weak part 313 and the recess 34, the resistance to bending of the first limiting part 31 can be further reduced when the internal pressure or temperature of the outer shell 20 reaches a threshold, so that the first limiting part 31 can pass through the electrode lead-out hole 231 in a timely manner.

[0306] Figure 15 A partial cross-sectional schematic diagram of a battery cell provided for other embodiments of this application; Figure 16 for Figure 15 The diagram shows a cross-sectional view of the electrode terminals.

[0307] like Figure 15 and Figure 16 As shown, in some embodiments, the electrode terminal 30 includes a terminal body 32, a first limiting portion 31, and a second limiting portion 33; at least a portion of the terminal body 32 is accommodated in the electrode lead-out hole 231; the first limiting portion 31 is located on the side of the wall portion 23 facing the electrode assembly 10 and protrudes from the outer peripheral surface 321 of the terminal body 32; the first limiting portion 31 is located on the side of the wall portion 23 away from the electrode assembly 10 and protrudes from the outer peripheral surface 321 of the terminal body 32; in the thickness direction Z, at least a portion of the wall portion 23 is sandwiched between the first limiting portion 31 and the second limiting portion 33.

[0308] In some embodiments, the first limiting portion 31 is provided with a groove 314 to form a weak portion 313.

[0309] In some embodiments, the terminal body 32 is provided with a through hole 323, which can be used to inject electrolyte. In some embodiments, the electrode terminal 30 further includes a sealing plate 35, which is connected to the terminal body 32 and seals the through hole 323.

[0310] In some embodiments, the terminal body 32, the first limiting part 31, and the second limiting part 33 are an integral structure, and the sealing plate 35 is welded to the terminal body 32.

[0311] In some embodiments, the through hole 323 is a stepped hole. At least a portion of the sealing plate 35 is accommodated within the through hole 323 and abuts against the stepped surface.

[0312] Figure 17 This is a three-dimensional structural diagram of a battery cell provided in some other embodiments of this application.

[0313] like Figure 17 As shown, in some embodiments, the projection of the wall portion 23 along its own thickness direction Z is rectangular.

[0314] In some embodiments, the battery cell 7 is a square battery cell.

[0315] In some embodiments, the wall portion 23 is an end cap 22.

[0316] According to some embodiments of this application, this application also provides a battery including a plurality of battery cells 7 of any of the above embodiments.

[0317] According to some embodiments of this application, this application also provides an electrical device, including a battery cell 7 of any of the above embodiments, wherein the battery cell 7 is used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems that utilize the battery cell 7.

[0318] Reference Figures 5 to 8 This application provides a cylindrical battery cell 7, which includes a housing 20, an electrode assembly 10, an electrode terminal 30, a current collector 40, and a sealing element 50.

[0319] The housing 20 includes a housing 21 and an end cap 22. One end of the housing 21 has an opening, and the end cap 22 closes to the opening. The housing 21 includes a side wall 212 and an end wall 211. The side wall 212 surrounds the outside of the electrode assembly 10, and the end wall 211 is disposed opposite to the opening. The end wall 211 is provided with an electrode lead-out hole 231.

[0320] The electrode assembly 10 is housed within the housing 20 and includes a tab 11. The electrode terminal 30 is disposed on the end wall 211 and electrically connected to the tab 11 via a current collector 40.

[0321] The electrode terminal 30 includes a terminal body 32, a first limiting portion 31, and a second limiting portion 33. At least a portion of the terminal body 32 is accommodated in the electrode lead-out hole 231. The first limiting portion 31 is located on the side of the end wall 211 facing the electrode assembly 10 and protrudes from the outer peripheral surface 321 of the terminal body 32. The first limiting portion 31 is located on the side of the end wall 211 away from the electrode assembly 10 and protrudes from the outer peripheral surface 321 of the terminal body 32. In the thickness direction Z, at least a portion of the end wall 211 is located between the first limiting portion 31 and the second limiting portion 33.

[0322] The seal 50 separates the electrode terminal 30 from the end wall 211. The electrode terminal 30 and the seal 50 together cover the electrode lead-out hole 231 to seal the electrode lead-out hole 231.

[0323] When the internal pressure or temperature of the housing 20 reaches a threshold, the first limiting part 31 can be bent and deformed, and the electrode terminal 30 is completely separated from the end wall 211, thereby connecting the internal space of the housing 20 with the external space through the electrode lead-out hole 231 and releasing the gas inside the housing 20.

[0324] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: The outer casing includes a wall portion, wherein the wall portion is provided with electrode lead-out holes; An electrode assembly, at least a portion of which is housed within the housing and includes tabs; An electrode terminal is disposed on the wall portion and covers at least a portion of the electrode lead-out hole, and the electrode terminal is electrically connected to the electrode tab; Wherein, at least a portion of the electrode terminals can deform when the internal pressure or temperature of the housing reaches a threshold, so that the internal space of the housing is connected to the external space through the electrode lead-out hole, and the gas inside the housing is released.

2. The battery cell of claim 1, wherein, At least a portion of the electrode terminals can detach from the wall when the internal pressure or temperature of the housing reaches the threshold.

3. The battery cell of claim 1, wherein, The electrode terminal includes a protrusion that extends radially out of the wall of the electrode lead-out hole, the protrusion being located on the side of the wall facing the electrode assembly, and the protrusion being deformable when the internal pressure or temperature of the housing reaches the threshold.

4. The battery cell of claim 3, wherein, The maximum dimension of the protrusion protruding from the wall of the electrode lead-out hole is L1, and the minimum distance between the periphery of the wall and the wall of the electrode lead-out hole is L2. L1 and L2 satisfy: 0.1≤L1 / L2≤0.

5.

5. The battery cell according to claim 3, characterized in that, The maximum dimension of the protrusion protruding from the wall of the electrode lead-out hole is L1, and the maximum thickness of the protrusion is T1; L1 and T1 satisfy: 0.25mm 2 ≤L1×T1≤25mm 2 .

6. The battery cell of claim 5, wherein, T1 is 0.5mm-5mm.

7. The battery cell of claim 3, wherein, From the central axis of the electrode lead-out hole toward the outer periphery of the protrusion, the thickness of at least a portion of the protrusion gradually decreases.

8. The battery cell of claim 3, wherein, The protrusion has a first surface facing the wall, and the wall has a second surface facing the protrusion. The second surface is perpendicular to the thickness direction of the wall. The first surface is inclined relative to the second surface toward the electrode assembly. In the thickness direction of the wall, the distance between the end of the first surface away from the electrode lead-out hole and the second surface is greater than the distance between the end of the first surface near the electrode lead-out hole and the second surface.

9. The battery cell of claim 3, wherein, The electrode terminal includes a terminal body and a first limiting portion connected to each other. At least a portion of the terminal body is accommodated in the electrode lead-out hole. The first limiting portion is located on the side of the wall facing the electrode assembly and protrudes from the outer peripheral surface of the terminal body. The first limiting portion includes the protrusion.

10. The battery cell of claim 9, wherein, The first limiting part has a weak part, and the first limiting part can be bent or broken along the weak part when the internal pressure or temperature of the shell reaches the threshold.

11. The battery cell of claim 10, wherein, At least a portion of the projection of the weak portion in the thickness direction of the wall is located within the electrode lead-out hole.

12. The battery cell of claim 11, wherein, The first limiting part includes a protrusion and a connecting part. The connecting part is used to connect the protrusion and the terminal body. The projection of the connecting part in the thickness direction of the wall is located between the outer peripheral surface of the terminal body and the hole wall of the electrode lead-out hole. The weak point is located at the connecting part.

13. The battery cell of claim 10, wherein, The electrode terminal is provided with a groove, and the weak part is formed at the bottom of the groove.

14. The battery cell of claim 13, wherein, The groove is provided on the surface of the first limiting portion facing the wall portion; and / or The groove is provided on the surface of the first limiting portion away from the wall portion.

15. The battery cell of claim 10, wherein, The electrode terminal is provided with a recess, which is recessed from the inside of the housing toward the outside of the housing along the thickness direction of the wall portion, and at least a portion of the recess is provided on the side of the terminal body facing the tab.

16. The battery cell of claim 15, wherein, The recess includes a first side and a second side. The first side is located on the outer side of the second side along the radial direction of the electrode lead-out hole. The first side is connected to the bottom surface of the recess and is inclined toward the side away from the central axis of the electrode terminal.

17. The battery cell of claim 15, wherein, The recess includes a first side and a second side. The first side is located on the outer side of the second side along the radial direction of the electrode lead-out hole. The second side is connected to the bottom surface of the recess and is inclined toward the side close to the central axis of the electrode terminal.

18. The battery cell of claim 15, wherein, The first limiting part can be bent toward the recess when the internal pressure or temperature of the outer shell reaches the threshold.

19. The battery cell of claim 15, wherein, The first limiting portion is formed by folding a portion of the electrode terminal.

20. The battery cell according to claim 15, characterized in that, The terminal body includes a terminal protrusion, and the recess is disposed around the terminal protrusion; In the thickness direction of the wall portion, the end face of the terminal protrusion facing the electrode tab is closer to the electrode tab than the first limiting portion.

21. The battery cell according to any one of claims 9-20, characterized in that, The electrode terminal further includes a second limiting portion, which protrudes from the outer peripheral surface of the terminal body and is disposed on the outer side of the wall portion; In the thickness direction of the wall portion, at least a portion of the wall portion is located between the protrusion and the second limiting portion.

22. The battery cell according to claim 21, characterized in that, In the radial direction of the electrode lead-out hole, the end of the second limiting portion away from the terminal body extends beyond the end of the first limiting portion away from the terminal body.

23. The battery cell according to claim 21, characterized in that, The first limiting part, the second limiting part, and the terminal body are integrally formed.

24. The battery cell of any one of claims 9-20, wherein, It also includes a seal, at least a portion of which is disposed between the first limiting portion and the wall portion.

25. The battery cell according to claim 1, characterized in that, The melting point of the electrode terminal is lower than the melting point of the wall portion.

26. The battery cell according to claim 25, characterized in that, The melting point of the electrode terminal is H1, and the melting point of the wall is H2, where H2-H1≥300℃.

27. The battery cell according to claim 1, characterized in that, The electrode terminals are made of aluminum or copper, and the wall is made of steel.

28. The battery cell according to claim 1, characterized in that, The housing includes a shell and an end cap. One end of the shell has an opening, and the end cap covers the opening. The shell includes a side wall and an end wall. The side wall surrounds the outside of the electrode assembly, and the end wall is disposed opposite to the opening. The wall portion is either the end cap or the end wall.

29. The battery cell according to claim 1, characterized in that, The projection of the wall portion along its own thickness direction is rectangular or circular.

30. A battery, comprising: It includes multiple battery cells according to any one of claims 1-29.

31. An electrical device, characterized in that, Includes the battery according to claim 30, the battery being used to provide electrical energy.

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