Battery cell, battery, and electric apparatus

Abstract

A battery cell, a battery, and an electric apparatus. The battery cell comprises a casing, an electrode assembly, and conductive components. The casing is provided with an electrode lead-out member. The electrode assembly is accommodated in the casing. The electrode assembly is of a cylindrical winding structure. The electrode assembly comprises a first electrode sheet, the first electrode sheet comprises a current collector and an active material layer, the current collector comprises a coating area coated with an active material layer and a tab not coated with the active material layer, and the coating area and the tab are arranged in a first direction. Each conductive component comprises a conductive main body and a bent portion, at least part of the conductive main body is connected to the tab to form a first connecting area, and the bent portion is configured to be electrically connected to the electrode lead-out member. The bent portion extends from the end of the conductive main body distant from the active material layer, and is continuously bent for multiple times. In the first direction, the bent portion entirely extends beyond the end part of the tab distant from the coating area.

Description

Battery cells, batteries, and electrical devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application 202310691862.2, filed on June 12, 2023, entitled “Battery Cell, Battery, and Electrical Device,” the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] With the development of new energy technology, batteries are used more and more widely, for example, in mobile phones, laptops, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and power tools.

[0005] The development of battery technology requires simultaneous consideration of multiple design factors, including performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge rate. Furthermore, battery reliability must be considered. Improving battery reliability is a key research topic in the battery field.

[0006] Summary of the Invention

[0007] The present application provides a battery cell, a battery, and an electrical device, which can improve reliability.

[0008] In a first aspect, the present application provides a battery cell comprising a housing, an electrode assembly and a conductive component. The housing is provided with an electrode lead-out piece. The electrode assembly is housed in the housing. The electrode assembly is a cylindrical wound structure. The electrode assembly comprises a first pole piece, the first pole piece comprising a current collector and an active material layer, the current collector comprising a coating area coated with an active material layer and a pole ear not coated with the active material layer, the coating area and the pole ear being arranged along a first direction. The conductive component comprises a conductive body and a bending portion, at least a portion of the conductive body is connected to the pole ear and forms a first connection area, and the bending portion is used to electrically connect to the electrode lead-out piece. The bending portion extends from one end of the conductive body away from the active material layer and is bent continuously multiple times. In the first direction, the bending portion as a whole extends beyond the end of the pole ear away from the coating area.

[0009] During the process of bending the conductive component to form the bent portion, the stress generated by the bending is transmitted to the tab through the first connection area. The tab and the conductive component are connected in the first connection area. Therefore, the first connection area is relatively strong and not easily deformed, which can reduce the stress transmitted to the junction between the tab and the coating area, thereby reducing the force on the active material layer, reducing the risk of active material shedding, and improving the reliability of the battery cell. The embodiments of the present application can reduce the risk of active material shedding and improve the reliability of the battery cell by connecting the conductive component to the tab and replacing the bending of the tab with the bending of the conductive component.

[0010] In some embodiments, the conductive component is wound into a cylindrical structure. The cylindrical conductive component has a larger flow area, which can reduce heat generation and improve the flow capacity of the battery cell.

[0011] In some embodiments, the conductive component is flattened to form a bent portion, and the bent portion forms a flattened end surface at one end away from the conductive body. The flattened end surface faces the electrode lead-out piece and is used to electrically connect to the electrode lead-out piece.

[0012] The flattened end surface can be used to contact and connect with other conductive structures to guide the current generated by the electrode assembly to the electrode lead. The flattened end surface is relatively flat, which can increase the direct contact area between the conductive component and other conductive structures, thereby improving the current carrying capacity.

[0013] In some embodiments, in the first direction, the first connection region and the bending portion are spaced apart.

[0014] During the process of bending the conductive component to form the bend, stress is transferred to the first connection area. Spacing the first connection area from the bend reduces the stress transferred to the first connection area, lowering the risk of connection failure between the conductive body and the tab. This embodiment of the present application also reduces the risk of bending the first connection area due to errors, improving the reliability of the connection between the conductive body and the tab.

[0015] In some embodiments, in the first direction, the minimum distance between the bending portion and the first connection area is D1, the maximum size of the bending portion is L1, and D1 and L1 satisfy: 0.5≤D1 / L1≤3.

[0016] Setting D1 / L1 to 0.5-3 can balance the stress on the first connection area and the space occupied by the conductive component. On the premise that the stress transmitted to the first connection area meets the requirements, the size of the conductive component can be reduced, thereby improving the space utilization and energy density of the battery cell.

[0017] In some embodiments, D1 is 1.5 mm-3.5 mm to balance the stress on the first connection area and the space occupied by the conductive component, reduce the risk of failure of the first connection area, and improve the space utilization and energy density of the battery cell.

[0018] In some embodiments, L1 is 1 mm to 3 mm to reduce the risk of the bent portion being welded through, reduce the stress transmitted to the first connection area, and improve the reliability and energy density of the battery cell.

[0019] In some embodiments, the conductive body is welded to the tab to form a first connection region. The battery cell further includes a reinforcement layer connected to the conductive body and covering at least a portion of the first connection region.

[0020] The reinforcement layer can enhance the strength of the electrode assembly in the first connection area, reducing the risk of cracking in the first connection area during the bending process of the bend; the reinforcement layer can also disperse the stress generated by bending, reduce the stress transmitted to the active material layer, and reduce the risk of active material shedding. In addition, after welding is completed, some particles will remain on the first connection area, and these particles may fall into the interior of the electrode assembly, causing a short circuit risk. The reinforcement layer can fix the particles on the first connection area, reduce the risk of particles falling into the electrode assembly, and improve reliability.

[0021] In some embodiments, the reinforcement layer includes an adhesive layer and a protective layer, with the protective layer bonded to the first connection region via the adhesive layer. The protective layer can block burrs on the second electrode piece, reducing the risk of the burrs conducting electricity to the first connection region and improving reliability. The adhesive layer can also fix particles remaining in the first connection region, reducing the risk of particles falling into the electrode assembly and improving reliability.

[0022] In some embodiments, the reinforcement layer is further connected to the active material layer and the portion of the tab located between the active material layer and the conductive body in the first direction. During the forming process of the bent portion, the reinforcement layer can connect the active material layer and the conductive body to the tab, thereby reducing the risk of active material shedding and the risk of failure of the first connection area, thereby improving the reliability of the battery cell.

[0023] In some embodiments, the elastic modulus of the reinforcement layer is greater than or equal to 0.2 MPa. The reinforcement layer has a high elastic modulus, which can support the first connection area during the forming process of the bent portion and during use of the battery cell, reducing deformation of the first connection area, reducing the risk of failure of the first connection area, and improving reliability.

[0024] In some embodiments, in the first direction, the minimum distance between the bend and the reinforcement layer is D2. The melting point of the reinforcement layer is T. T×D2 ≥ 150°C·mm. Limiting T×D2 to greater than or equal to 150°C·mm can reduce the risk of softening and falling off of the reinforcement layer during welding, thereby improving the reliability of the battery cell.

[0025] In some embodiments, T is greater than or equal to 150° C. to reduce the risk of softening and falling off of the reinforcement layer during welding and improve the reliability of the battery cell.

[0026] In some embodiments, the electrode assembly further includes a second electrode sheet and a separator, wherein the polarity of the first electrode sheet is opposite to that of the second electrode sheet, and the separator is used to separate the first electrode sheet from the second electrode sheet. In the first direction, a distance D3 between an edge of the reinforcing layer near the bend and an edge of the separator near the bend is less than or equal to 2 mm.

[0027] When the edge of the reinforcement layer near the bend extends beyond the edge of the separator near the bend, the larger the distance D3, the more additional space the reinforcement layer occupies in the first direction, and the lower the battery cell space utilization. When the edge of the separator near the bend extends beyond the edge of the reinforcement layer near the bend, the larger the distance D3, the smaller the reinforcement layer, and the higher the risk of the first connection area being exposed and puncturing the separator. Limiting D3 to less than or equal to 2 mm can reduce the risk of separator puncture and minimize energy density loss.

[0028] In some embodiments, the battery cell includes two conductive components, and at least a portion of the tab is located between conductive bodies of the two conductive components.

[0029] The two conductive components can increase the flow area, reduce heat generation, and enhance the flow capacity of the battery cell. The bent portions of the two conductive components are wound together to form a denser area, reducing the risk of particles falling into the electrode assembly through the gaps between the bent portions.

[0030] In some embodiments, when the bent portions of the two conductive components are flattened to be parallel to the first direction, a distance D4 between the ends of the two conductive components away from the active material layer in the first direction is 0 mm-6 mm.

[0031] The larger D4 is, the greater the difference in the size of the two conductive components during the bending process. In this embodiment, D4 is limited to 0mm-6mm, which can reduce the risk of tearing due to excessive compression of a single conductive component, improve the current carrying capacity, and enhance the reliability of the battery cell.

[0032] In some embodiments, when the bent portions of the two conductive components are flattened to be parallel to the first direction, the ends of the two conductive components away from the active material layer are offset in the first direction.

[0033] When bending two conductive components, one conductive component is compressed first, and after a period of time, both conductive components are compressed simultaneously. This embodiment of the application can reduce the pressure required to bend the conductive components, thereby reducing the force on the active material layer and reducing the risk of active material falling off.

[0034] In some embodiments, the conductive bodies of the two conductive components are connected to the tabs to form a first connection region, so as to increase the overall structural strength and improve the current carrying capacity.

[0035] In some embodiments, in the first direction, a portion of the conductive body extends beyond the end of the tab away from the coating region; portions of two conductive bodies extending beyond the tab in the first direction are connected to form a second connection region.

[0036] During the bending process, the second connection area can act as a barrier, reducing the stress transferred to the first connection area, minimizing deformation of the tab and reducing the risk of active material loss. The second connection area can also transmit current between the two conductive bodies, improving the current consistency of the two conductive parts.

[0037] In some embodiments, the second connection region is spaced apart from the bend in the first direction. This spacing reduces stress transmitted to the second connection region, lowering the risk of connection failure between the two conductive bodies. This embodiment also reduces the risk of bending the second connection region due to errors, improving the reliability of the connection between the two conductive bodies.

[0038] In some embodiments, the current collector includes an insulating substrate and a conductive layer, wherein the conductive layer is disposed on a surface of the insulating substrate, and the active material layer is coated on the conductive layer. The coated region includes the portion of the conductive layer coated with the active material layer, and the tab includes the portion of the conductive layer not coated with the active material layer. The conductive body is connected to the conductive layer.

[0039] Compared to current collectors made of metal foil, current collectors with a multi-layer structure that includes an insulating substrate have a lower weight when compared to current collectors made of the same thickness, further improving the energy density of the battery cell. The thinner the conductive layer, the smaller the burr produced at the puncture site when the current collector is pierced by an external structure. This reduces the risk of burrs piercing the separator, thereby reducing the possibility of short circuits and improving the reliability of the battery cell.

[0040] In some embodiments, the tab is welded to the conductive body to form a first connection region. The current collector includes two conductive layers, which are disposed on either side of the insulating substrate. The first connection region connects the conductive body and the two conductive layers.

[0041] The first connection region can electrically connect the two conductive layers, and the current collected by the two conductive layers can be transmitted outward through the conductive component, thereby improving the current-carrying capacity of the battery cell.

[0042] In some embodiments, the battery cell includes two conductive components, at least a portion of the tab is located between the conductive bodies of the two conductive components, the tab and the two conductive bodies are welded to form a first connection region, and the first connection region connects the two conductive bodies and the two conductive layers.

[0043] In the first connection area, the two conductive bodies and the two conductive layers are electrically connected, and the current collected by the two conductive layers can be transmitted outward through the two conductive components, thereby improving the current flow capacity of the battery cell.

[0044] In some embodiments, the first connection area includes a plurality of solder joints. By providing a plurality of separately arranged solder joints, heat accumulation can be reduced during the soldering process, temperature rise can be lowered, and soldering performance can be improved.

[0045] In some embodiments, the number of welding points is k; the capacity of the battery cell is C; the thickness of the conductive layer is t; the welding points form a welding surface on the surface of the conductive body away from the conductive layer, and the perimeter of the welding surface is L2. k, C, t and L2 satisfy: 0.1mm 2 / mAh≤(t×k×L2) / C≤1mm 2 / mAh.

[0046] t, k, and L2 are all positively correlated with the current capacity between the conductive layer and the conductive component. The larger C is, the higher the current capacity requirement of the battery cell for the first connection area. In addition, t, k, and L2 are also positively correlated with the connection strength between the conductive layer and the conductive component. The larger t×k×L2 is, the higher the connection strength between the conductive layer and the conductive component is, and the lower the risk of cracking of the weld during the bending forming process of the bending portion. (t×k×L2) / C is limited to greater than or equal to 0.1mm 2 / mAh to meet the requirements of overcurrent capacity, improve the connection strength between the conductive layer and the conductive parts, and reduce the risk of solder joint cracking.

[0047] t×k×L2 is also positively correlated with the space occupied by the first connection area. The larger t×k×L2 is, the more space the first connection area occupies. (t×k×L2) / C is defined as less than or equal to 1 mm 2 / mAh, in order to reduce the loss of energy density while meeting the requirements of overcurrent capability.

[0048] In some embodiments, L2 is 0.8 mm to 6 mm to reduce the welding area and reduce heat accumulation during welding.

[0049] In some embodiments, the battery cell further includes a current collecting component connected to the electrode lead-out member. The current collecting component is welded to the bent portion. The bent portion is bent into multiple sections, which can be wound to form a compact structure. This allows the current collecting component to tightly abut and weld against the bent portion, improving weld strength and current handling capacity.

[0050] In some embodiments, the bend portion is provided with a weakening structure. By providing the weakening structure, the conductive component can be guided to bend at a predetermined position, thereby reducing the stress generated during the forming process of the bend portion, and reducing the risk of tab deformation and the risk of active material layer shedding.

[0051] In some embodiments, the bent portion is formed into a weak structure by opening a through hole, and the hole opening process is simple and easy to implement.

[0052] In a second aspect, the present application provides a battery comprising a plurality of battery cells provided by any embodiment of the first aspect.

[0053] In a third aspect, the present application provides an electrical device, comprising a battery cell provided by any embodiment of the first aspect, wherein the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0055] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0056] FIG2 is a schematic diagram of an explosion of a battery provided in some embodiments of the present application;

[0057] FIG3 is an exploded schematic diagram of the battery module shown in FIG2 ;

[0058] FIG4 is an exploded schematic diagram of a battery cell provided in some embodiments of the present application;

[0059] FIG5 is a partial cross-sectional schematic diagram of a battery cell provided in some embodiments of the present application;

[0060] FIG6 is a schematic structural diagram of an electrode assembly of a battery cell provided in some embodiments of the present application after partial expansion;

[0061] FIG7 is an enlarged schematic diagram of the frame in FIG5;

[0062] FIG8 is a schematic diagram of a first pole piece and a conductive component of a battery cell before winding, provided in some embodiments of the present application;

[0063] FIG9 is a schematic cross-sectional view taken along line AA in FIG8 ;

[0064] FIG10 is an enlarged schematic diagram of the circle frame in FIG8;

[0065] FIG11 is a partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of the present application;

[0066] FIG12 is a partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of the present application;

[0067] FIG13 is an enlarged schematic diagram of the circle frame of FIG12;

[0068] FIG14 is a schematic diagram of the first pole piece and the conductive component of FIG12 before winding;

[0069] FIG15 is a schematic partial cross-sectional view of a battery cell provided in some embodiments of the present application.

[0070] In the accompanying drawings, the drawings are not necessarily drawn to scale.

[0071] The reference numerals are as follows:

[0072] 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Housing; 5a. First housing portion; 5b. Second housing portion; 5c. Accommodation space; 6. Battery module; 7. Battery cell;

[0073] 10. Electrode assembly; 11. First pole piece; 111. Current collector; 111a. Insulating substrate; 111b. Conductive layer; 1111. Coating area; 1112. Tab; 112. Active material layer; 12. Second pole piece; 13. Separator; 13a. Edge;

[0074] 20. Housing; 20a. Electrode lead-out member; 21. Shell; 22. End cap; 23. Electrode terminal;

[0075] 30. Conductive component; 31. Conductive body; 32. Bend portion; 321. Flattened end surface; 322. Weak structure; 323. Through hole;

[0076] 40. First connection area; 41. Welding point; 41a. Welding surface;

[0077] 50. Current collecting components;

[0078] 60, reinforcement layer; 61, adhesive layer; 62, protective layer; 60a, edge;

[0079] 70. Second connection area;

[0080] Z, first direction; V, winding direction; X, winding axis. DETAILED DESCRIPTION

[0081] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0082] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0083] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0084] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0085] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0086] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0087] In the embodiments of this application, "parallel" includes not only absolute parallelism but also approximately parallelism as commonly understood in engineering practice. Similarly, "perpendicular" also includes not only absolute perpendicularity but also approximately perpendicularity as commonly understood in engineering practice. For example, if the angle between two directions is 85°-90°, they are considered perpendicular; if the angle between two directions is 0°-5°, they are considered parallel.

[0088] The term "plurality" used in this application refers to two or more (including two).

[0089] In the embodiment of the present application, the battery cell may be a secondary battery cell. A secondary battery cell refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0090] The battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-hydrogen battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc., and the embodiments of the present application are not limited to this.

[0091] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions (such as lithium ions) are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0092] 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.

[0093] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0094] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0095] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and at least one of its modified compounds, etc.

[0096] In some embodiments, the negative electrode may be a negative electrode sheet, which 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.

[0097] As an example, the negative electrode current collector can be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium can be used. The metal foam can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

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

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

[0100] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0101] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode sheet and the negative electrode sheet.

[0102] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical and mechanical stability can be selected.

[0103] As an example, the primary 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 positioned 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, which is disposed between the positive electrode and the negative electrode, and serves to transport ions and 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 specifically limit the type of electrolyte, and the electrolyte can be selected based on needs. The electrolyte can be liquid, gel, or solid.

[0106] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[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 difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0108] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent can also be an ether solvent. Ether solvents can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0109] The gel electrolyte consists of a polymer-based electrolyte framework 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, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0112] As an example, the inorganic solid electrolyte can be an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphide, germanium silver sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0113] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0114] In some embodiments, the electrode assembly is a wound structure. Optionally, the electrode assembly is a cylindrical wound structure.

[0115] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0116] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0117] As an example, the battery cells may be cylindrical, prismatic, soft-pack or other shaped battery cells. Prismatic battery cells include square-shell, blade-shaped, and polygonal batteries. Polygonal batteries may be, for example, hexagonal batteries.

[0118] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0119] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0120] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0121] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0122] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0123] In a cylindrical electrode assembly, the tabs usually need to be flattened, smoothed or other processes to bend the ends of the tabs and form a dense area. The dense area can be used to connect with other conductive structures to conduct the electrical energy generated by the electrode assembly.

[0124] However, during the bending process, the stress on the tab is transferred to the active material layer of the electrode assembly, causing the active material to fall out. Once the active material falls into the electrode assembly, it may pierce the separator, causing risks such as short circuits and affecting the reliability of the battery cell.

[0125] In view of this, an embodiment of the present application provides a technical solution, which reduces the force on the active material layer, reduces the risk of active material falling off, and improves the reliability of the battery cell by connecting a conductive component to the electrode tab and replacing the bending of the electrode tab with the bending of the conductive component.

[0126] The electrode assembly described in the embodiments of the present application is suitable for use in batteries and electrical devices using batteries.

[0127] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may include fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles may include pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0128] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device.

[0129] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0130] As shown in FIG1 , a battery 2 is provided inside the vehicle 1. The battery 2 may be provided at the bottom, head, or tail of the vehicle 1. The battery 2 may be used to power the vehicle 1. For example, the battery 2 may serve as an operating power source for the vehicle 1.

[0131] The vehicle 1 may further include a controller 3 and a motor 4 . The controller 3 is used to control the battery 2 to supply power to the motor 4 , for example, to meet the power requirements of the vehicle 1 during startup, navigation, and driving.

[0132] In some embodiments of the present application, the battery 2 can not only serve as the operating power source of the vehicle 1, but also serve as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0133] Figure 2 is an exploded view of a battery according to some embodiments of the present invention. As shown in Figure 2, the battery 2 includes a housing 5 and a battery cell (not shown), which is housed within the housing 5. A battery cell is the smallest unit of a battery.

[0134] The housing 5 is used to house battery cells and can have various structures. In some embodiments, the housing 5 can include a first housing portion 5a and a second housing portion 5b. The first housing portion 5a and the second housing portion 5b overlap each other, and the first housing portion 5a and the second housing portion 5b together define a storage space 5c for accommodating the battery cells. The second housing portion 5b can be a hollow structure with one end open. The first housing portion 5a is a plate-like structure, and the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. The first housing portion 5a and the second housing portion 5b can also be hollow structures with one end open. The open side of the first housing portion 5a overlaps the open side of the second housing portion 5b to form the housing 5 with the storage space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0135] In order to improve the sealing performance after the first box body 5a and the second box body 5b are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 5a and the second box body 5b.

[0136] Assuming that the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a can also be called an upper box cover, and the second box body portion 5b can also be called a lower box body.

[0137] In battery 2, there can be one or more battery cells. If there are multiple battery cells, they can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections. Multiple battery cells can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire battery module can be housed within housing 5. Alternatively, multiple battery cells can be first connected in series, in parallel, or in a hybrid configuration to form a battery module 6, and then multiple battery modules 6 can be connected in series, in parallel, or in a hybrid configuration to form a single unit housed within housing 5.

[0138] FIG3 is a schematic diagram of an explosion of the battery module shown in FIG2 .

[0139] As shown in FIG3 , in some embodiments, there are multiple battery cells 7, which are first connected in series, in parallel, or in hybrid to form a battery module 6. The multiple battery modules 6 are then connected in series, in parallel, or in hybrid to form a whole and housed in a box.

[0140] The multiple battery cells 7 in the battery module 6 can be electrically connected via a busbar component to achieve parallel connection, series connection, or mixed connection of the multiple battery cells 7 in the battery module 6 .

[0141] The battery cell 7 may be a cylindrical battery cell, a square battery cell, or a battery cell of other shapes.

[0142] Figure 4 is an exploded schematic diagram of a battery cell provided in some embodiments of the present application; Figure 5 is a partial cross-sectional schematic diagram of a battery cell provided in some embodiments of the present application; Figure 6 is a structural schematic diagram of an electrode assembly of a battery cell provided in some embodiments of the present application after partial expansion; Figure 7 is an enlarged schematic diagram of the box in Figure 5.

[0143] 4 to 7 , some embodiments of the present application provide a battery cell 7 comprising a housing 20, an electrode assembly 10, and a conductive component 30. The housing 20 is provided with an electrode lead 20a. The electrode assembly 10 is housed within the housing 20. The electrode assembly 10 is a cylindrical wound structure.

[0144] The electrode assembly 10 includes a first electrode sheet 11, which includes a current collector 111 and an active material layer 112. The current collector 111 includes a coating area 1111 coated with the active material layer 112 and a pole ear 1112 not coated with the active material layer 112. The coating area 1111 and the pole ear 1112 are arranged along a first direction Z.

[0145] The conductive component 30 includes a conductive body 31 and a bent portion 32. At least a portion of the conductive body 31 is connected to the electrode tab 1112 and forms a first connection region 40. The bent portion 32 is used to electrically connect to the electrode lead 20a. The bent portion 32 extends from the end of the conductive body 31 away from the active material layer 112 and bends continuously multiple times. In the first direction Z, the bent portion 32 extends entirely beyond the end of the electrode tab 1112 away from the coating region 1111.

[0146] The housing 20 is a hollow structure, and a space is formed inside the housing to accommodate the electrode assembly 10 and the electrolyte. The shape of the housing 20 can be determined according to the specific shape of the electrode assembly 10. For example, the housing 20 can be a rectangular parallelepiped housing.

[0147] As an example, the housing 20 includes a shell 21 and an end cover 22 . The shell 21 has an opening, and the end cover 22 is used to cover the opening.

[0148] The housing 21 is a component used to cooperate with the end cover 22 to form an internal cavity of the battery cell 7. The formed internal cavity can be used to accommodate the electrode assembly 10, electrolyte and other components.

[0149] The housing 21 and the end cap 22 may be separate components. For example, an opening may be provided on the housing 21 , and the end cap 22 may be placed over the opening to form an internal cavity of the battery cell 7 .

[0150] The housing 21 can have various shapes and sizes, such as a rectangular parallelepiped, a 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 housing 21 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and the present embodiment does not impose any particular limitation on this.

[0151] 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 (e.g., copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.). In this way, the end cap 22 is less likely to deform when subjected to compression or collision, thereby providing the battery cell 7 with higher structural strength and improved reliability.

[0152] The end cover 22 is connected to the housing 21 by welding, bonding, clamping or other methods.

[0153] The housing 21 may be open at one end or at both ends. In some examples, the housing 21 may be open at one end, with one end cap 22 provided to cover the housing 21. In other examples, the housing 21 may be open at both ends, with two end caps 22 provided to cover the two openings of the housing 21, respectively.

[0154] The electrode lead-out member 20a can be used to electrically connect the electrode assembly 10 to an external circuit to enable charging and discharging of the electrode assembly 10. Optionally, the electrode lead-out member 20a can be used to connect to a busbar component.

[0155] The form of the electrode lead-out member 20a can be set according to design requirements.

[0156] For example, in some examples, the housing 21 is electrically connected to the tab 1112 of the first electrode piece 11 , and the housing 21 may serve as the electrode lead-out member 20 a .

[0157] In other examples, the end cap 22 is electrically connected to the electrode tab 1112 of the first electrode piece 11 , and the end cap 22 can serve as the electrode lead-out member 20 a .

[0158] In some other examples, the housing 20 further includes an electrode terminal 23, which can be mounted on the housing 21 or the end cap 22. The electrode terminal 23 is electrically connected to the tab 1112 of the first electrode sheet 11, and the electrode lead-out member 20a can include the electrode terminal 23.

[0159] The electrode assembly 10 is a component where electrochemical reactions occur in the battery cell 7. One or more electrode assemblies 10 may be contained in the housing 20.

[0160] The electrode assembly 10 includes a first electrode plate 11 and a second electrode plate 12. The polarity of the first electrode plate 11 is opposite to that of the second electrode plate 12. If the first electrode plate 11 is a positive electrode plate, the second electrode plate 12 is a negative electrode plate; if the first electrode plate 11 is a negative electrode plate, the second electrode plate 12 is a positive electrode plate. Optionally, the electrode assembly 10 also includes a separator 13, which is used to insulate and isolate the first electrode plate 11 from the second electrode plate 12.

[0161] The electrode assembly 10 is a wound structure. Exemplarily, the first electrode sheet 11, the separator 13, and the second electrode sheet 12 are wound together along a winding direction V to form a cylindrical wound structure.

[0162] The electrode assembly 10 of the embodiment of the present application is generally cylindrical, and its shape allows deviations from conventional cognition, and does not require the shape of the electrode assembly 10 to be absolutely cylindrical.

[0163] The current collector 111 has two surfaces facing each other in its thickness direction, and at least one surface of the current collector 111 is coated with an active material layer 112. As an example, the current collector 111 may be a metal foil, a composite current collector 111 or other current collecting structures.

[0164] The active material layer 112 includes active materials. For example, if the first electrode sheet 11 is a positive electrode sheet, the active material layer 112 includes positive electrode active materials. If the first electrode sheet 11 is a negative electrode sheet, the active material layer 112 includes negative electrode active materials.

[0165] The active material layer 112 can be used to generate an electrochemical reaction with the electrolyte to generate current. The coating area 1111 can collect the current generated by the active material layer 112 and guide the current to the electrode lead-out member 20 a through the tab 1112 and the conductive component 30 .

[0166] Both surfaces of the tab 1112 are not covered by the active material layer 112. The surface of the tab 1112 may not be provided with a coating, or may be coated with other coatings that do not contain active materials.

[0167] The tab 1112 may extend from an end of the coating region 1111 along the first direction Z. Optionally, the first direction Z is perpendicular to the winding direction V.

[0168] There may be one or more tabs 1112. In some examples, there may be one tab 1112 that is wound multiple times along the winding direction V. In other examples, there may be multiple tabs 1112 that are spaced apart along the winding direction V.

[0169] The tab 1112 has two surfaces facing each other along its thickness direction, and a conductive component 30 is connected to at least one surface of the tab 1112. In some examples, the tab 1112 is connected to one conductive component 30; in other examples, the tab 1112 is connected to two conductive components 30 at the same time, with the two conductive components 30 connected to two surfaces of the tab 1112 respectively.

[0170] The conductive body 31 may be entirely connected to the tab 1112 or only partially connected to the tab 1112. Alternatively, a portion of the conductive body 31 is stacked and connected to the tab 1112 in the thickness direction of the tab 1112.

[0171] The conductive body 31 can be connected to the tab 1112 by welding, bonding or other methods.

[0172] The first connection region 40 may be a continuous region, or may include a plurality of sub-regions spaced apart from each other.

[0173] In the first direction Z, the end of the conductive body 31 away from the active material layer 112 may extend beyond the electrode tab 1112 or may be flush with the end of the electrode tab 1112 away from the coating region 1111 .

[0174] In the first direction Z, the bend portion 32 extends from the end of the conductive body 31 away from the active material layer 112 and extends entirely beyond the end of the tab 1112 away from the coating region 1111. In the radial direction of the electrode assembly 10, the bend portion 32 does not overlap with the tab 1112.

[0175] As an example, during the molding process of the battery cell 7 , a portion of the conductive component 30 may be bent by kneading, flattening, squeezing or other processes to form a bent portion 32 .

[0176] Compared to the bend portion 32 , the conductive body 31 generally extends along the first direction Z. As an example, a portion of the conductive body 31 may be tilted at a smaller angle relative to the first direction Z. For example, the angle between the tilted portion of the conductive body 31 and the first direction Z may be less than 10°.

[0177] The bending portion 32 is bent continuously for multiple times. Optionally, the bending portion 32 is bent into an S-shape, a wave shape or other shapes.

[0178] The bending portion 32 and the first connecting area 40 may be arranged adjacent to each other or spaced apart.

[0179] The bent portion 32 may be directly connected to the electrode lead-out member 20 a or indirectly connected to the electrode lead-out member 20 a through other conductive structures.

[0180] In the embodiment of the present application, during the process of bending the conductive component 30 to form the bent portion 32, the stress generated by the bending is transmitted to the tab 1112 through the first connection area 40; the tab 1112 and the conductive component 30 are connected at the first connection area 40. Therefore, the first connection area 40 has high strength and is not easily deformed, which can reduce the stress transmitted to the junction of the tab 1112 and the coating area 1111, thereby reducing the force on the active material layer 112, reducing the risk of active material shedding, and improving the reliability of the battery cell 7. The embodiment of the present application reduces the risk of active material shedding and improves the reliability of the battery cell 7 by connecting the conductive component 30 to the tab 1112 and replacing the bending of the tab 1112 with the bending of the conductive component 30.

[0181] In some embodiments, the conductive component 30 is wound into a cylindrical structure. The cylindrical conductive component 30 has a larger flow area, which can reduce heat generation and improve the flow capacity of the battery cell 7.

[0182] In some embodiments, the winding axis X of the electrode assembly 10 is parallel to the first direction Z, and the conductive component 30 is wound around the winding axis X for multiple turns to form a cylindrical structure.

[0183] In some embodiments, a central hole is formed at the winding center of the conductive component 30 .

[0184] In some embodiments, the conductive component 30 is flattened to form a bent portion 32, and the end of the bent portion 32 away from the conductive body 31 forms a flattened end surface 321, which faces the electrode lead-out member 20a and is used to electrically connect to the electrode lead-out member 20a.

[0185] The flattened end surface 321 can be used to contact and connect with other conductive structures to guide the current generated by the electrode assembly 10 to the electrode lead 20a. The flattened end surface 321 is relatively flat, which can increase the direct contact area between the conductive component 30 and other conductive structures and improve the current carrying capacity.

[0186] In some embodiments, the battery cell 7 further includes a current collecting component 50 , which is connected to the electrode lead-out member 20 a .

[0187] Optionally, the current collecting component 50 is connected to the electrode lead-out member 20 a by welding, clamping, bonding or other means to achieve electrical connection between the current collecting component 50 and the electrode lead-out member 20 a.

[0188] In some embodiments, the current collecting component 50 is welded to the bent portion 32. The bent portion 32 is bent into multiple sections, which can be wound to form a dense structure, so that the current collecting component 50 can be tightly abutted and welded to the bent portion 32, improving welding strength and current flow capacity.

[0189] In some embodiments, the current collecting component 50 abuts against the flattened end surface 321 of the bent portion 32 .

[0190] In some embodiments, the current collecting component 50 and the bent portion 32 are connected by laser welding. The bent portion 32 is relatively dense, which can reduce the risk of laser leakage during welding, reduce the possibility of the separator 13 being burned by the laser, and improve the reliability of the battery cell 7.

[0191] In some embodiments, in the first direction Z, the first connection region 40 is spaced apart from the bending portion 32 .

[0192] During the process of bending the conductive component 30 to form the bent portion 32, stress is transmitted to the first connection region 40. Spacing the first connection region 40 from the bent portion 32 can reduce the stress transmitted to the first connection region 40, thereby lowering the risk of connection failure between the conductive body 31 and the tab 1112. This embodiment of the present application also reduces the risk of bending the first connection region 40 due to errors, thereby improving the reliability of the connection between the conductive body 31 and the tab 1112.

[0193] In some embodiments, in the first direction Z, the minimum distance between the bent portion 32 and the first connecting region 40 is D1, and the maximum dimension of the bent portion 32 is L1. D1 and L1 satisfy: 0.5≤D1 / L1≤3.

[0194] The larger D1 is, the smaller the stress transmitted to the first connection area 40 during the forming process of the bent portion 32, but the larger the space occupied by the conductive component 30 in the first direction Z, and the lower the energy density of the battery cell 7. Conversely, the smaller D1 is, the greater the stress transmitted to the first connection area 40 during the forming process of the bent portion 32, but the smaller the space occupied by the conductive component 30 in the first direction Z, and the higher the energy density of the battery cell 7.

[0195] Assuming the density of the bent portion 32 meets the requirements, the larger L1 is, the greater the pressure required to bend the conductive component 30, the greater the stress transmitted to the first connection area 40 during the bending process, and the larger the space occupied by the bent portion 32. Conversely, the smaller L1 is, the smaller the pressure required to bend the conductive component 30 is, the smaller the stress transmitted to the first connection area 40 during the bending process, but the risk of the bent portion 32 being welded through is higher.

[0196] In the embodiment of the present application, D1 / L1 is set to 0.5-3, which can balance the stress on the first connection area 40 and the space occupied by the conductive component 30. On the premise that the stress transmitted to the first connection area 40 meets the requirements, the size of the conductive component 30 is reduced, thereby improving the space utilization and energy density of the battery cell 7.

[0197] Optionally, the value of D1 / L1 is 0.5, 0.7, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8 or 3.

[0198] In some embodiments, D1 is 1.5 mm to 3.5 mm. Optionally, D1 is 1.5 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, or 3.5 mm.

[0199] The embodiment of the present application can balance the stress on the first connection area 40 and the space occupied by the conductive component 30, reduce the risk of failure of the first connection area 40, and improve the space utilization and energy density of the battery cell 7.

[0200] In some embodiments, L1 is 1 mm to 3 mm. Alternatively, L1 is 1 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, or 3 mm.

[0201] The embodiment of the present application can reduce the risk of the bent portion 32 being welded through, and reduce the stress transmitted to the first connection area 40 , thereby improving the reliability and energy density of the battery cell 7 .

[0202] In some embodiments, the minimum distance between the bent portion 32 and the isolating member 13 is greater than or equal to 1.5 mm in the first direction Z. This embodiment of the present application can reduce the heat transferred to the isolating member 13 during welding of the bent portion 32 , thereby lowering the risk of burns to the isolating member 13 and improving reliability.

[0203] In some embodiments, the conductive body 31 is welded to the tab 1112 to form a first connection region 40 . Optionally, the conductive body 31 is connected to the tab 1112 by ultrasonic welding.

[0204] In some embodiments, the battery cell 7 further includes a reinforcement layer 60 , which is connected to the conductive body 31 and covers at least a portion of the first connection region 40 .

[0205] The reinforcement layer 60 may cover the entire first connection area 40 or only a portion of the first connection area 40. Optionally, the reinforcement layer 60 completely covers the first connection area 40.

[0206] The reinforcement layer 60 may be provided only on the conductive body 31 , or may be provided on both the conductive body 31 and the tab 1112 .

[0207] The reinforcement layer 60 can enhance the strength of the electrode assembly in the first connection area 40, reducing the risk of cracking in the first connection area 40 during the bending process of the bend portion 32. The reinforcement layer 60 can also disperse the stress generated by bending, reducing the stress transmitted to the active material layer 112, and reducing the risk of active material shedding. In addition, after welding is completed, some particles will remain on the first connection area 40. These particles may fall into the interior of the electrode assembly 10 and cause a short circuit risk. The reinforcement layer 60 can fix the particles on the first connection area 40, reducing the risk of particles falling into the electrode assembly 10 and improving reliability.

[0208] In some embodiments, the reinforcement layer 60 includes an insulating material, which can improve insulation and reduce the risk of short circuits.

[0209] In some embodiments, the reinforcement layer 60 includes an adhesive. For example, the adhesive may include at least one of epoxy resin, acrylate, and styrene-butadiene rubber. Alternatively, the reinforcement layer 60 is formed by applying a colloid.

[0210] In some embodiments, the reinforcement layer 60 further includes ceramic particles, which may include at least one of boehmite, silicon oxide, and zirconium oxide. The ceramic particles may enhance the puncture strength and insulation of the reinforcement layer 60.

[0211] In some embodiments, the reinforcement layer 60 includes an adhesive and ceramic particles. For example, the adhesive, ceramic particles, and solvent are mixed into a slurry, which is then applied to the pole piece 11 and the conductive component 30 . The slurry is cured to form the reinforcement layer 60 .

[0212] In some embodiments, the reinforcement layer 60 further includes a color recognition agent, such as charcoal, Prussian blue, or the like.

[0213] In some embodiments, the reinforcement layer 60 is further connected to the active material layer 112 and a portion of the tab 1112 located between the active material layer 112 and the conductive body 31 in the first direction Z.

[0214] During the forming process of the bending portion 32 , the reinforcing layer 60 can connect the active material layer 112 and the conductive body 31 to the tab 1112 , thereby reducing the risk of active material falling off and the risk of failure of the first connection area 40 , and improving the reliability of the battery cell 7 .

[0215] During the molding process of the first electrode sheet 11, the active material layer 112 is generally rolled to increase the compaction density of the active material layer 112. During rolling, the coating area 1111 is subjected to stress, while the tab 1112 is not. This causes stress concentration at the junction of the coating area 1111 and the tab 1112. In some embodiments, the reinforcement layer 60 can cover the junction of the coating area 1111 and the tab 1112, thereby reducing the risk of cracking of the current collector 111 and improving the flow capacity.

[0216] In some embodiments, the strength of the reinforcement layer 60 is greater than the strength of the tab 1112, which in turn is greater than the strength of the conductive body 31. Compared to the tab 1112 and the conductive body 31, the reinforcement layer 60 is less susceptible to deformation, and can effectively support the first connection region 40, reducing deformation of the first connection region 40, lowering the risk of failure of the first connection region 40, and improving reliability.

[0217] In some embodiments, the elastic modulus of the reinforcement layer 60 is greater than or equal to 0.2 MPa.

[0218] As an example, the elastic modulus of the reinforcement layer 60 refers to the Young's modulus of the reinforcement layer 60 .

[0219] The reinforcement layer 60 has a high elastic modulus, which can support the first connection area 40 during the forming process of the bending portion 32 and the use of the battery cell 7, reduce the deformation of the first connection area 40, reduce the risk of failure of the first connection area 40, and improve reliability.

[0220] Optionally, the elastic modulus of the reinforcement layer 60 may be greater than or equal to 0.5 MPa.

[0221] Optionally, the elastic modulus of the reinforcement layer 60 may be 0.2 MPa, 0.3 MPa, 0.5 MPa, 0.8 MPa, 1 MPa, 2 MPa, or 5 MPa.

[0222] In some embodiments, in the first direction Z, the minimum distance between the bending portion 32 and the reinforcement layer 60 is D2. The melting point of the reinforcement layer 60 is T. T×D2≥150° C.·mm.

[0223] The bent portion 32 can be connected to other structures (such as a current collecting component) by welding. During the welding process, heat is conducted to the reinforcement layer 60.

[0224] The smaller D2 is, the more heat is conducted to the reinforcing layer 60 during welding, the higher the temperature of the reinforcing layer 60 is, and the higher the risk of the reinforcing layer 60 softening or falling off is; the larger D2 is, the less heat is conducted to the reinforcing layer 60 during welding, and the lower the risk of the reinforcing layer 60 softening or falling off is.

[0225] The smaller T is, the higher the risk of the reinforcing layer 60 softening and falling off when heated; the larger T is, the lower the risk of the reinforcing layer 60 softening and falling off when heated.

[0226] In the embodiment of the present application, T×D2 is limited to be greater than or equal to 150° C.·mm, which can reduce the risk of softening and falling off of the reinforcement layer 60 during the welding process and improve the reliability of the battery cell 7.

[0227] Optionally, T×D2 is greater than or equal to 500° C.·mm.

[0228] Alternatively, T×D2 is 150°C·mm, 250°C·mm, 350°C·mm, 450°C·mm, 500°C·mm, 600°C·mm, 800°C·mm, 1000°C·mm, 1500°C·mm or 2000°C·mm.

[0229] In some embodiments, T is greater than or equal to 150° C. to reduce the risk of softening and falling off of the reinforcement layer 60 during welding and improve the reliability of the battery cell 7 .

[0230] Alternatively, T is 150°C, 170°C, 180°C, 200°C, 250°C, 300°C, 400°C, 500°C, 700°C, 900°C, 1000°C, 1500°C, 1800°C or 2000°C.

[0231] In some embodiments, the dimension of the reinforcement layer 60 in the first direction Z may be 1 mm-10 mm.

[0232] Optionally, the dimension of the reinforcement layer 60 in the first direction Z may be 2.5 mm-5 mm.

[0233] Optionally, the dimension of the reinforcement layer 60 in the first direction Z may be 1 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4.5 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0234] In some embodiments, in the first direction Z, the area of ​​the active material layer 112 that faces away from the current collector 111 and is covered by the reinforcement layer 60 is 0.5 mm to 1 mm. Alternatively, in the first direction Z, the area of ​​the active material layer 112 that faces away from the current collector 111 and is covered by the reinforcement layer 60 is 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm.

[0235] The reinforcing layer 60 can fix the active material layer 112 to reduce the shedding of the active material.

[0236] In some embodiments, the thickness of the reinforcement layer 60 is 3 μm-100 μm. Optionally, the thickness of the reinforcement layer 60 is 3 μm, 5 μm, 10 μm, 20 μm, 30 μm, 50 μm, 70 μm, 80 μm, 90 μm or 10 μm.

[0237] In some embodiments, the electrode assembly 10 further includes a second electrode piece 12 and an isolating member 13 . The polarity of the first electrode piece 11 is opposite to that of the second electrode piece 12 . The isolating member 13 is used to separate the first electrode piece 11 from the second electrode piece 12 .

[0238] In some embodiments, in the first direction Z, a distance D3 between an edge 60 a of the reinforcement layer 60 close to the bending portion 32 and an edge 13 a of the isolation member 13 close to the bending portion 32 is less than or equal to 2 mm.

[0239] When the edge of the reinforcing layer 60 near the bend 32 extends beyond the edge of the separator 13 near the bend 32, the larger the distance D3, the more additional space the reinforcing layer 60 occupies in the first direction Z, and the lower the space utilization of the battery cell 7. When the edge of the separator 13 near the bend 32 extends beyond the edge of the reinforcing layer 60 near the bend 32, the larger the distance D3, the smaller the size of the reinforcing layer 60, and the higher the risk of the first connection area 40 being exposed and puncturing the separator 13.

[0240] The present application defines D3 as less than or equal to 2 mm, which can reduce the risk of the separator 13 being punctured and reduce the loss of energy density.

[0241] 8 is a schematic diagram of a first electrode sheet and a conductive component of a battery cell before winding provided in some embodiments of the present application; FIG9 is a schematic cross-sectional view taken along line AA in FIG8 ; and FIG10 is an enlarged schematic diagram of the circle frame in FIG8 .

[0242] Please refer to FIG. 5 to FIG. 10 . In some embodiments, the battery cell 7 includes two conductive components 30 , and at least a portion of the tab 1112 is located between the conductive bodies 31 of the two conductive components 30 .

[0243] The two conductive components 30 can increase the flow area, reduce heat generation, and enhance the flow capacity of the battery cell 7. The bent portions 32 of the two conductive components 30 are wound together to form a more compact area (e.g., a flattened area), reducing the risk of particles falling into the electrode assembly 10 through the gaps between the bent portions 32.

[0244] In some embodiments, when the bent portions 32 of the two conductive components 30 are flattened to be parallel to the first direction Z, a distance D4 between the ends of the two conductive components 30 away from the active material layer 112 in the first direction Z is 0 mm-6 mm.

[0245] For example, the electrode assembly 10 may be disassembled and the first electrode sheet 11 may be unfolded. Then, the bent portion 32 of the conductive component 30 may be flattened again using a device, and then the distance D4 may be measured.

[0246] The larger D4 is, the greater the difference in the size of the two conductive components 30 during the bending process. In this embodiment, D4 is limited to 0mm-6mm, which can reduce the risk of tearing due to excessive compression of a single conductive component 30, improve the current carrying capacity, and enhance the reliability of the battery cell 7.

[0247] Optionally, D4 is 0 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm or 6 mm.

[0248] In some embodiments, when the bent portions 32 of the two conductive components 30 are flattened to be parallel to the first direction Z, the difference in size between the two conductive components 30 along the first direction Z is 0 mm to 6 mm. Optionally, the ends of the two conductive components 30 close to the active material layer 112 are aligned in the first direction Z.

[0249] In some embodiments, when the bent portions 32 of the two conductive components 30 are flattened to be parallel to the first direction Z, the ends of the two conductive components 30 away from the active material layer 112 are offset in the first direction Z. Exemplarily, D4 is greater than 0 mm.

[0250] When bending the two conductive components 30, one conductive component 30 is compressed first, and after a period of time, both conductive components 30 are compressed simultaneously. This embodiment of the present application can reduce the pressure required to bend the conductive components 30, thereby reducing the force on the active material layer 112 and reducing the risk of active material shedding.

[0251] In some embodiments, D4 is 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, or 5 mm.

[0252] In some embodiments, when the bent portions 32 of the two conductive components 30 are flattened to be parallel to the first direction Z, the size of each conductive component 30 along the first direction Z is greater than or equal to 3 mm.

[0253] In some embodiments, the conductive bodies 31 of the two conductive components 30 are connected to the tabs 1112 to form a first connection region 40 , so as to enhance the overall structural strength and improve the current carrying capacity.

[0254] In some embodiments, the current collector 111 includes an insulating substrate 111a and a conductive layer 111b. The conductive layer 111b is disposed on the surface of the insulating substrate 111a, and the active material layer 112 is coated on the conductive layer 111b. The coated area 1111 includes the portion of the conductive layer 111b coated with the active material layer 112, and the tab 1112 includes the portion of the conductive layer 111b not coated with the active material layer 112. The conductive body 31 is connected to the conductive layer 111b.

[0255] Exemplarily, the tab 1112 also includes a portion of the insulating base 111 a that does not overlap with the active material layer 112 , and the coating region 1111 also includes a portion of the insulating base 111 a that corresponds to the active material layer 112 .

[0256] The conductive layer 111b can be provided on one side of the insulating substrate 111a or on two opposite sides of the insulating substrate 111a. Alternatively, the conductive layer 111b is provided on both sides of the insulating substrate 111a, and the surfaces of the two conductive layers 111b are coated with the active material layer 112.

[0257] Alternatively, the insulating base 111 a may include a polymer material, and the polymer material includes polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene or polyethylene.

[0258] The conductive layer 111 b may include a metal material, and the metal material includes aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.

[0259] As an example, a metal material is deposited onto the surface of the insulating base 111 a and forms the conductive layer 111 b .

[0260] When the thickness is the same, the multi-layered current collector 111 including the insulating substrate 111a is lighter than a current collector made of metal foil, thereby further improving the energy density of the battery cell 7. The conductive layer 111b has a smaller thickness. When the current collector 111 is punctured by an external structure, the conductive layer 111b produces smaller burrs at the punctured location. This reduces the risk of the burr piercing the separator 13, thereby reducing the possibility of a short circuit and improving the reliability of the battery cell 7.

[0261] The conductive layer 111b is thin and has low strength. If the tab 1112 is bent directly (for example, flattened), the conductive layer 111b is easily damaged during the bending process, affecting the current carrying capacity of the conductive layer 111b. In addition, if the conductive layer 111b is damaged, welding leaks may also occur when the tab 1112 is welded to the current collecting component. The embodiment of the present application can reduce the risk of deformation and damage of the conductive layer 111b by transferring the conductive component 30 to the tab 1112, improve the conductive performance of the conductive layer 111b, and reduce the risk of welding leaks.

[0262] In some embodiments, the thickness of the conductive layer 111b may be 0.5 μm-5 μm. Alternatively, the thickness of the conductive layer 111b may be 1 μm-3 μm.

[0263] In some embodiments, the thickness of the current collector 111 may be 2 μm to 50 μm. Alternatively, the thickness of the current collector 111 may be 4 μm to 20 μm.

[0264] In some embodiments, the thickness of the conductive component 30 is 2 μm-30 μm. Alternatively, the thickness of the conductive component 30 is 3 μm-20 μm.

[0265] In some embodiments, the thickness of the conductive feature 30 is greater than the thickness of the conductive layer 111 b .

[0266] In some embodiments, the tab 1112 is welded to the conductive body 31 to form a first connection region 40. The current collector 111 includes two conductive layers 111b, which are disposed on either side of the insulating base 111a. The first connection region 40 connects the conductive body 31 and the two conductive layers 111b.

[0267] The first connection region 40 can electrically connect the two conductive layers 111 b , and the current collected by the two conductive layers 111 b can be transmitted outward through the conductive component 30 , thereby improving the current-carrying capacity of the battery cell 7 .

[0268] In some embodiments, the battery cell 7 includes two conductive components 30, and at least a portion of the tab 1112 is located between the conductive bodies 31 of the two conductive components 30. The tab 1112 and the two conductive bodies 31 are welded to form a first connection region 40, which connects the two conductive bodies 31 and the two conductive layers 111b.

[0269] In the first connection area 40 , the two conductive bodies 31 and the two conductive layers 111 b are electrically connected. The current collected by the two conductive layers 111 b can be transmitted outward through the two conductive components 30 , thereby improving the current carrying capacity of the battery cell 7 .

[0270] In some embodiments, the first connection region 40 includes a plurality of solder joints 41 .

[0271] The welding spot 41 may be circular, rectangular, triangular, trapezoidal, elliptical, polygonal or other shapes.

[0272] By providing a plurality of separately arranged welding points 41 , heat accumulation can be reduced during the welding process, temperature rise can be lowered, and welding performance can be improved.

[0273] In some embodiments, each solder joint 41 connects two conductive bodies 31 and two conductive layers 111 b .

[0274] In some embodiments, ultrasonic welding is performed on the overlapping area of ​​the conductive component 30 and the conductive layer 111b while applying pressure to melt and squeeze out the insulating base 111a. Welding spots 41 can pass through the insulating base 111a to connect the two conductive layers 111b.

[0275] In some embodiments, the plurality of welding points 41 of the first connection region 40 are arranged in an array along the winding direction V and the first direction Z.

[0276] In some embodiments, a dimension D5 of the first connection region 40 along the first direction Z is 1 mm to 5 mm. Optionally, D5 is 2 mm to 4 mm.

[0277] As an example, D5 is 1 mm, 2 mm, 3 mm, 4 mm or 5 mm.

[0278] In some embodiments, the number of welding points 41 is k; the capacity of the battery cell 7 is C; the thickness of the conductive layer 111b is t; the welding points 41 form a welding surface 41a on the surface of the conductive body 31 away from the conductive layer 111b, and the perimeter of the welding surface 41a is L2. k, C, t and L2 satisfy: 0.1mm 2 / mAh≤(t×k×L2) / C≤1mm 2 / mAh.

[0279] t, k, and L2 are all positively correlated with the current flow capacity between the conductive layer 111b and the conductive component 30. For example, when t and k are constant, a larger L2 indicates a larger weld area between the conductive body 31 and the conductive layer 111b, and a stronger current flow capacity between the conductive layer 111b and the conductive component 30. When t and L2 are constant, a larger k indicates a larger area of ​​the first connection region 40, and a stronger current flow capacity between the conductive layer 111b and the conductive component 30. When L2 and k are constant, a larger t indicates a smaller resistance of the conductive layer 111b, and a stronger current flow capacity between the conductive layer 111b and the conductive component 30.

[0280] The larger C is, the higher the requirement of the battery cell 7 on the current-carrying capacity of the first connection area 40 is.

[0281] In addition, t, k, and L2 are also positively correlated with the connection strength between the conductive layer 111b and the conductive component 30. The larger t×k×L2 is, the higher the connection strength between the conductive layer 111b and the conductive component 30 is, and the lower the risk of cracking of the solder joint 41 during the bending forming process of the bending portion 32.

[0282] In the embodiment of the present application, (t×k×L2) / C is limited to be greater than or equal to 0.1 mm 2 / mAh, so as to meet the requirements of overcurrent capacity, improve the connection strength between the conductive layer 111b and the conductive component 30, and reduce the risk of cracking of the solder joint 41.

[0283] t×k×L2 is also positively correlated with the space occupied by the first connection area 40 . The larger t×k×L2 is, the more space the first connection area 40 occupies and the lower the energy density of the battery cell 7 .

[0284] In the embodiment of the present application, (t×k×L2) / C is limited to less than or equal to 1 mm 2 / mAh, in order to reduce the loss of energy density while meeting the requirements of overcurrent capability.

[0285] In some embodiments, L2 is 0.8 mm to 6 mm. In the present embodiment, L2 is limited to be greater than or equal to 0.8 mm to increase the flow capacity at a single weld point 41. L2 is limited to be less than or equal to 6 mm to reduce the welding area and reduce heat accumulation during welding.

[0286] Optionally, L2 is 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 4 mm, 5 mm or 6 mm.

[0287] FIG11 is a schematic partial cross-sectional view of a battery cell provided in some other embodiments of the present application.

[0288] 11 , in some embodiments, a portion of the conductive body 31 extends beyond the tab 1112 and away from the end of the coating region 1111 in the first direction Z. The portions of the two conductive bodies 31 extending beyond the tab 1112 in the first direction Z are connected to form a second connection region 70 .

[0289] During the forming process of the bent portion 32, the second connection region 70 can act as a barrier, reducing the stress transmitted to the first connection region 40, minimizing deformation of the tab 1112, and reducing the risk of active material shedding. The second connection region 70 can also transmit current between the two conductive bodies 31, improving the current consistency of the two conductive components 30.

[0290] In some embodiments, the two conductive bodies 31 are welded to form a second connection region 70 .

[0291] In some embodiments, the first connection region 40 and the second connection region 70 are formed in the same welding process.

[0292] In some embodiments, in the first direction Z, the second connection region 70 is spaced apart from the bending portion 32 .

[0293] Distancing the second connection region 70 from the bent portion 32 can reduce stress transmitted to the second connection region 70, lowering the risk of connection failure between the two conductive bodies 31. This embodiment of the present application also reduces the risk of bending the second connection region 70 due to errors, improving the reliability of the connection between the two conductive bodies 31.

[0294] In some embodiments, the reinforcement layer 60 also covers the second connection region 70 .

[0295] In some embodiments, in the first direction Z, a total dimension D6 of the first connection region 40 and the second connection region 70 is 2 mm to 10 mm. Optionally, D6 is 2 mm to 5 mm.

[0296] The larger D6 is, the larger the space occupied by the first connection area 40 and the second connection area 70 in the first direction Z; the smaller D6 is, the smaller the connection strength between the tab 1112 and the two conductive components 30 is.

[0297] The embodiment of the present application can improve the connection strength between the tab 1112 and the two conductive components 30, reduce the risk of connection failure between the tab 1112 and the conductive components 30, and reduce the loss of energy density.

[0298] Figure 12 is a partial cross-sectional schematic diagram of a battery cell provided in some other embodiments of the present application; Figure 13 is an enlarged schematic diagram of the circle frame in Figure 12; and Figure 14 is a schematic diagram of the first electrode and conductive component in Figure 12 before winding.

[0299] 12 to 14 , in some embodiments, the bent portion 32 is provided with a weak structure 322 .

[0300] The strength of the weak structure 322 is relatively weak compared to the strength of other parts of the bend portion 32. The weak structure 322 is a portion of the bend portion 32 that is easily deformed. In this embodiment, the weak structure 322 can be formed by thinning a predetermined area of ​​the bend portion 32, performing a material treatment on the predetermined area of ​​the bend portion 32, heating the predetermined area of ​​the bend portion 32, or performing a hole-forming process on the predetermined area of ​​the bend portion 32, or by other methods.

[0301] By providing the weak structure 322 , the conductive component 30 can be guided to bend at a preset position, thereby reducing stress generated during the forming process of the bent portion 32 , and lowering the risk of deformation of the tab 1112 and the risk of the active material layer 112 falling off.

[0302] In some embodiments, the bending portion 32 forms a weak structure 322 by defining a through hole 323 .

[0303] By forming the through hole 323, the cross-sectional area of ​​the bent portion 32 can be reduced to form a weak structure 322. The hole forming process is simple and easy to implement.

[0304] In some embodiments, there are multiple through holes 323. Optionally, the multiple through holes 323 are spaced apart along the winding direction V; after the first pole piece 11 is flattened, the multiple through holes 323 are spaced apart along the length direction of the first pole piece 11.

[0305] In some embodiments, the through hole 323 is spaced apart from the first connection region 40 .

[0306] FIG15 is a schematic partial cross-sectional view of a battery cell provided in some embodiments of the present application.

[0307] As shown in FIG. 15 , the reinforcement layer 60 includes an adhesive layer 61 and a protective layer 62 . The protective layer 62 is bonded to the pole piece 11 and the conductive component 30 through the adhesive layer 61 .

[0308] The protective layer 62 can block the burrs of the second electrode 12, reduce the risk of the burrs 12 being connected to the first connection area 40, and improve reliability; the glue layer 61 can fix the particles remaining in the first connection area 40, reduce the risk of particles falling into the electrode assembly, and improve reliability.

[0309] In some embodiments, the hardness of the protective layer 62 is greater than the hardness of the conductive component 30. The protective layer 62 has a higher hardness to reduce the risk of being pierced by burrs.

[0310] In some embodiments, the protective layer 62 is made of insulating plastic.

[0311] In some embodiments, the material of the protective layer 62 is PET (polyethylene terephthalate).

[0312] In some embodiments, the reinforcement layer 60 comprises tape.

[0313] According to some embodiments of the present application, the present application further provides a battery comprising a plurality of battery cells 7 according to any one of the above embodiments.

[0314] According to some embodiments of the present application, the present application further provides an electrical device comprising a battery cell 7 according to any of the above embodiments, the battery cell 7 being used to provide power to the electrical device. The electrical device may be any of the aforementioned devices or systems using the battery cell 7.

[0315] 4 to 10 , an embodiment of the present application provides a cylindrical battery cell 7 , which includes a housing 20 , an electrode assembly 10 , a current collecting component 50 , and two conductive components 30 .

[0316] The housing 20 includes a shell 21, an end cap 22, and an electrode terminal 23. The shell 21 has an opening at one end along the first direction Z. The end cap 22 is used to cover the opening. The shell 21 has a bottom wall opposite to the end cap 22. The electrode terminal 23 is mounted on the bottom wall.

[0317] The electrode assembly 10 is housed in the housing 20 and includes a first electrode 11, a second electrode 12, and a separator 13. The polarity of the first electrode 11 is opposite to that of the second electrode 12. The separator 13 is used to insulate the first electrode 11 from the second electrode 12.

[0318] The first pole piece 11 , the separator 13 and the second pole piece 12 are wound together along a winding direction V to form a cylindrical winding structure.

[0319] The first electrode sheet 11 includes a current collector 111 and an active material layer 112 . The current collector 111 includes a coating area 1111 coated with the active material layer 112 and a tab 1112 not coated with the active material layer 112 . The coating area 1111 and the tab 1112 are arranged along a first direction Z. The tab 1112 is located on a side of the coating area 1111 close to the electrode terminal 23 .

[0320] The current collector 111 includes an insulating substrate 111a and a conductive layer 111b. The conductive layer 111b is disposed on the surface of the insulating substrate 111a, and the active material layer 112 is coated on the conductive layer 111b. The coated area 1111 includes the portion of the conductive layer 111b coated with the active material layer 112, and the tab 1112 includes the portion of the conductive layer 111b not coated with the active material layer 112.

[0321] The conductive component 30 includes a conductive body 31 and a bent portion 32. At least a portion of the tab 1112 is located between the conductive bodies 31 of the two conductive components 30. The tab 1112 and the two conductive bodies 31 are welded together to form a first connection region 40. The first connection region 40 includes a plurality of weld points 41, each of which connects the two conductive layers 111b and the two conductive bodies 31.

[0322] The bent portion 32 extends from the end of the conductive body 31 away from the active material layer 112 and bends continuously multiple times. In the first direction Z, the bent portion 32 extends entirely beyond the end of the tab 1112 away from the coated area 1111. Exemplarily, the bent portion 32 is formed by flattening the conductive component 30; the bent portions 32 of the two conductive components 30 form a dense region with a flattened end surface 321 facing the electrode terminal 23.

[0323] The current collecting member is located between the electrode terminal 23 and the flattened end surface 321 , and the current collecting member is welded to the electrode terminal 23 and the flattened end surface 321 .

[0324] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. A battery cell, comprising: A housing provided with an electrode lead-out member; an electrode assembly, contained in the housing, the electrode assembly being a cylindrical winding structure, the electrode assembly comprising a first pole sheet, the first pole sheet comprising a current collector and an active material layer, the current collector comprising a coating area coated with the active material layer and a pole ear not coated with the active material layer, the coating area and the pole ear being arranged along a first direction; and A conductive component, comprising a conductive body and a bent portion, at least a portion of the conductive body is connected to the electrode tab to form a first connection area, and the bent portion is used to be electrically connected to the electrode lead-out member; The bent portion extends from one end of the conductive body away from the active material layer and is bent continuously for multiple times; in the first direction, the bent portion as a whole exceeds the end of the electrode tab away from the coating area.

2. The cylindrical battery cell according to claim 1, wherein: The conductive component is wound into a cylindrical structure.

3. The battery cell according to claim 1 or 2, wherein: The conductive component is flattened to form the bent portion, and one end of the bent portion away from the conductive body forms a flattened end surface, which faces the electrode lead-out member and is used for electrical connection with the electrode lead-out member.

4. The battery cell according to any one of claims 1 to 3, wherein: In the first direction, the first connection area and the bending portion are spaced apart.

5. The battery cell according to claim 4, wherein: In the first direction, the minimum distance between the bending portion and the first connecting area is D1, the maximum size of the bending portion is L1, and D1 and L1 satisfy: 0.5≤D1 / L1≤3.

6. The battery cell according to claim 5, wherein: D1 is 1.5mm-3.5mm.

7. The battery cell according to claim 5 or 6, wherein: L1 is 1mm-3mm.

8. The battery cell according to any one of claims 1 to 7, wherein: The conductive body is welded to the electrode lug to form the first connection area; The battery cell further includes a reinforcement layer connected to the conductive body and covering at least a portion of the first connection region.

9. The battery cell according to claim 8, wherein: The reinforcement layer includes an adhesive layer and a protective layer, and the protective layer is bonded to the first connection area through the adhesive layer.

10. The battery cell according to claim 8 or 9, wherein: The reinforcing layer is also connected to the active material layer and a portion of the electrode tab located between the active material layer and the conductive body in the first direction.

11. The battery cell according to any one of claims 8 to 10, wherein: The elastic modulus of the reinforcement layer is greater than or equal to 0.2 MPa.

12. The battery cell according to any one of claims 8 to 11, wherein: In the first direction, the minimum distance between the bending portion and the reinforcement layer is D2; The melting point of the reinforcement layer is T; 150℃·mm≤T×D2.

13. The battery cell according to claim 12, wherein: T is greater than or equal to 150°C.

14. The battery cell according to any one of claims 8 to 13, wherein: The electrode assembly further includes a second pole piece and a separator, the polarity of the first pole piece is opposite to the polarity of the second pole piece, and the separator is used to separate the first pole piece from the second pole piece; In the first direction, a distance between an edge of the reinforcing layer close to the bending portion and an edge of the isolating member close to the bending portion is less than or equal to 2 mm. 15 . The battery cell according to claim 1 , comprising two of the conductive components, wherein at least a portion of the tab is located between the conductive bodies of the two conductive components.

16. The battery cell according to claim 15, wherein: When the bent portions of the two conductive components are flattened to be parallel to the first direction, a distance between the ends of the two conductive components away from the active material layer in the first direction is 0 mm-6 mm.

17. The battery cell according to claim 16, wherein: When the bent portions of the two conductive members are flattened to be parallel to the first direction, the ends of the two conductive members away from the active material layer are offset in the first direction.

18. The battery cell according to any one of claims 15 to 17, wherein: The conductive bodies of the two conductive components are connected to the electrode tabs to form a first connection region.

19. The battery cell according to claim 18, wherein: In the first direction, a portion of the conductive body extends beyond the electrode tab and is away from an end of the coating region; portions of two conductive bodies extending beyond the electrode tab in the first direction are connected to form a second connection region.

20. The battery cell according to claim 19, wherein: In the first direction, the second connection area is spaced apart from the bending portion.

21. The battery cell according to any one of claims 1 to 20, wherein: The current collector comprises an insulating substrate and a conductive layer, wherein the conductive layer is disposed on the surface of the insulating substrate, and the active material layer is coated on the conductive layer; The coating area includes a portion of the conductive layer coated with the active material layer, and the tab includes a portion of the conductive layer not coated with the active material layer; The conductive body is connected to the conductive layer.

22. The battery cell according to claim 21, wherein: The tab is welded to the conductive body to form a first connection area; The current collector comprises two conductive layers, and the two conductive layers are respectively arranged on both sides of the insulating substrate; The first connection region connects the conductive body and the two conductive layers.

23. The battery cell according to claim 22, comprising two of the conductive components, wherein at least a portion of the tab is located between the conductive bodies of the two conductive components; The electrode tab and the two conductive bodies are welded to form the first connection region, and the first connection region connects the two conductive bodies and the two conductive layers.

24. The battery cell according to claim 22 or 23, wherein: The first connection area includes a plurality of welding spots.

25. The battery cell according to claim 24, wherein: The number of the welding points is k; the capacity of the battery cell is C; the thickness of the conductive layer is t; the welding points form a welding surface on the surface of the conductive body away from the conductive layer, and the perimeter of the welding surface is L2; k, C, t and L2 satisfy: 0.1mm 2 / mAh≤(t×k×L2) / C≤1mm 2 / mAh。 26. The battery cell according to claim 25, wherein: L2 is 0.8mm-6mm.

27. The battery cell according to any one of claims 1 to 26, further comprising a current collecting component connected to the electrode lead-out member; The current collecting component is welded to the bent portion.

28. The battery cell according to any one of claims 1 to 27, wherein: The bending portion is provided with a weak structure.

29. The battery cell according to claim 28, wherein: The bending portion forms the weak structure by providing a through hole.

30. A battery comprising a plurality of battery cells according to any one of claims 1 to 29.

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

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