Battery cell, battery, and electric device

Abstract

A battery cell (20), a battery (10), and an electric device, relating to the technical field of batteries. The battery cell (20) comprises: an electrode assembly (22) comprising a negative electrode sheet, the negative electrode sheet comprising a negative electrode active material which allows for reversible metal ion intercalation / deintercalation, and the negative electrode active material comprising a silicon element; a casing (21), an opening being formed in the casing (21), and the casing (21) being used for accommodating the electrode assembly (22); an end cover (23) covering the opening; and a current collector component (24) accommodated in the casing (21) and located on the side of the electrode assembly (22) facing the end cover (23), wherein the current collector component (24) is electrically connected to a tab of the electrode assembly (22) and the casing (21), the current collector component (24) comprises a current collector body (240) and an elastic portion (241), the current collector body (240) is of an annular structure, the elastic portion (241) is located on the inner side of the current collector body (240) and is connected to the current collector body (240), and at least part of the elastic portion (241) in the thickness direction of the end cover (23) protrudes out of the current collector body (240) and abuts against the end cover (23). The product is beneficial to taking into account the energy density and reliability of the battery cell (20).

Description

Battery cells, batteries and electrical devices Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0002] With the increasing severity of environmental pollution, the new energy industry has attracted more and more attention. In the new energy industry, battery technology is an important factor in its development.

[0003] The development of battery technology requires consideration of numerous design factors, such as energy density, cycle life, and reliability. Silicon-containing materials as negative electrode active materials contribute to higher energy density in battery cells. However, these cells exhibit a high expansion rate, which negatively impacts reliability. Therefore, developing a battery cell that balances energy density and reliability is a pressing technical challenge.

[0004] Summary of the Invention

[0005] The present application provides a battery cell, a battery, and an electrical device, which can take into account both the energy density and reliability of the battery cell.

[0006] In a first aspect, a battery cell is provided, comprising: an electrode assembly, comprising a negative electrode pole piece, the negative electrode pole piece comprising a negative electrode active material capable of reversibly extracting and embedding metal ions, the negative electrode active material comprising silicon; a shell, provided with an opening, the shell being used to accommodate the electrode assembly; an end cover, covering the opening; a current collecting member, accommodated in the shell and located on a side of the electrode assembly facing the end cover, the current collecting member being electrically connected to the electrode tab of the electrode assembly and the shell; wherein the current collecting member comprises a current collecting body and an elastic portion, the current collecting body being an annular structure, the elastic portion being located on the inner side of the current collecting body and connected to the current collecting body, and the elastic portion protruding from the current collecting body at least partially along the thickness direction of the end cover and abutting against the end cover.

[0007] In an embodiment of the present application, the current collecting member is located on the side of the electrode assembly facing the end cap and is electrically connected to the electrode tab and the shell of the electrode assembly. In this way, the electrical connection between the electrode assembly and the shell can be achieved through the current collecting member. The negative electrode active material in the battery cell includes silicon, the battery cell has a higher energy density and the degree of expansion of the electrode assembly in the battery cell is greater. The elastic portion in the current collecting member has the ability to elastically deform. When the electrode assembly expands, the elastic portion is compressed to provide space for the expansion of the electrode assembly. Moreover, the deformable elastic portion can weaken the squeezing effect on the electrode assembly compared to the non-deformable rigid component, thereby reducing the risk of the electrode assembly being squeezed, which is beneficial to improving the reliability of the battery cell. Therefore, the technical solution of the embodiment of the present application can take into account both the energy density and reliability of the battery cell.

[0008] In one possible implementation, the elastic portion is capable of deforming during the charge and discharge process of the battery cell. During the charge and discharge process of the battery cell, the electrode assembly expands. Since the elastic portion is capable of deforming during the charge and discharge process of the battery cell, the elastic portion can be compressed to provide space for the expansion of the electrode assembly, thereby reducing the risk of the electrode assembly being squeezed.

[0009] In a possible implementation, the end cover is provided with a first protrusion, the first protrusion protrudes toward the electrode assembly along a thickness direction of the end cover, and the first protrusion abuts against the elastic portion.

[0010] In the above technical solution, the provision of the first protrusion is conducive to improving the strength of the end cover, and the abutment between the first protrusion and the elastic portion is also conducive to reducing the size of the elastic portion protruding from the current collecting body.

[0011] In one possible implementation, the current collecting member further includes a central portion located inwardly of the elastic portion. Thus, the elastic portion is located between the central portion and the current collecting body, and the central portion corresponds to the center region of the electrode tab, thereby providing a certain degree of support for the tab.

[0012] In a possible implementation, the central portion abuts against the tab of the electrode assembly. In this way, the central portion can provide a certain support for the tab, which is beneficial for reducing the shaking of the electrode assembly in the housing.

[0013] In one possible implementation, the elastic portion includes a first piece, a second piece, and a center portion, the first piece is connected to the inner side of the current collecting body and extends obliquely toward the end cover, the second piece is connected to the outer side of the center portion and extends obliquely toward the end cover, the first piece and the second piece are connected at an angle greater than 0° and less than 180° to form a contact area, and the contact area abuts the end cover.

[0014] In the above technical solution, the central portion abuts against the electrode assembly, the abutting area formed by connecting the first sheet and the second sheet abuts against the end cover, and the elastic portion has the ability of elastic deformation. In this way, during the expansion of the electrode assembly, the abutting area is compressed to provide space for the expansion of the electrode assembly, and the central portion can play a softer supporting role for the electrode assembly, which can reduce the strength of the extrusion of the electrode assembly, thereby reducing the risks of powder loss, lithium precipitation, etc. caused by excessive extrusion of the electrode assembly.

[0015] In one possible implementation, the end cap includes an end cap body and a first protrusion. The first protrusion protrudes toward the electrode assembly along the thickness direction of the end cap, and the first protrusion abuts the abutment area. The provision of the first protrusion helps to increase the strength of the end cap and also facilitates the abutment between the end cap and the abutment area of ​​the elastic portion.

[0016] In a possible implementation, the elastic portion is provided with a first through hole penetrating the elastic portion along a thickness direction of the elastic portion, and the first through hole extends from the first sheet to the second sheet.

[0017] The provision of the first through hole is more conducive to the deformation of the elastic portion, thereby further reducing the risk of the electrode assembly being squeezed; in addition, the provision of the first through hole is also conducive to the discharge of internal high-temperature and high-pressure substances when the battery cell experiences thermal runaway.

[0018] In one possible implementation, there are multiple elastic portions, each spaced apart along the circumference of the current collecting body. This allows for a more even distribution of the elastic portions within the current collecting member, resulting in more uniform deformation of the multiple elastic portions, thereby more evenly alleviating the compressive forces acting on the electrode assembly and reducing the risk of varying degrees of compression in different regions of the electrode assembly. Furthermore, the spacing between adjacent elastic portions facilitates the formation of a smoother venting channel, facilitating the discharge of high-temperature, high-pressure materials within the battery cells during thermal runaway.

[0019] In one possible implementation, the current collecting component also includes a current collecting sheet connected to the current collecting body, a current collecting sheet is provided between two adjacent elastic parts, a side surface of the current collecting sheet facing away from the end cover is connected to the electrode tab of the electrode assembly, and the current collecting sheet and the elastic part are spaced apart.

[0020] In the above technical solution, the surface of the current collector facing away from the end cap is connected to the electrode assembly, allowing current from the electrode assembly to be transferred to the housing through the current collector. The current collector is spaced from the elastic portion, creating a clear venting channel between the two, facilitating the smooth discharge of emissions from the battery cells. Furthermore, a spacer is provided between the current collector and the elastic portion, allowing the current collector to move relative to the current collector body, reducing the risk of compression and tearing of the electrode assembly.

[0021] In one possible implementation, at least one current collecting sheet is welded to the electrode tab of the electrode assembly to form a plurality of welds, and the plurality of welds are spaced apart along the circumference of the current collecting body. The provision of the plurality of welds helps to enhance the connection strength between the electrode tab and the current collecting sheet.

[0022] In one possible implementation, the welding portion includes a first welding portion and two second welding portions, the first welding portion being located between the two second welding portions, and the length of the first welding portion being greater than the length of the second welding portion. In this way, the arrangement of the first and second welding portions adapts to the shape of the current collecting sheet, facilitating welding between the welding portions and the current collecting sheet.

[0023] In a possible implementation, the end cover is provided with an end cover body and a pressure relief mechanism, the pressure relief mechanism is located on the inner side of the end cover body, and the elastic portion abuts against the pressure relief mechanism.

[0024] In the above technical solution, the pressure relief mechanism is located on the inner side of the end cover body, which can reduce the risk of the pressure relief mechanism interfering with components outside the battery cell and being damaged, and is conducive to improving the long-term reliability of the pressure relief mechanism; the elastic part abuts against the pressure relief mechanism, facilitating the connection between the elastic part and the end cover.

[0025] In one possible implementation, the pressure relief mechanism is provided with a first protrusion, which protrudes toward the electrode assembly along the thickness direction of the end cap and abuts against the abutment area of ​​the elastic portion, thereby achieving a connection between the elastic portion and the end cap.

[0026] In one possible implementation, the end cap is provided with a scored groove, the area defined by the scored groove forming the pressure relief mechanism, and the first protrusion is located inside the scored groove and spaced apart from the scored groove. This facilitates the preparation of the scored groove and reduces adverse effects on the precision of the scored groove; it also helps reduce the risk of interference between the pressure relief mechanism and structures outside the battery cell.

[0027] In one possible implementation, a stopper is provided on the inner side of the housing, the current collecting member abuts against the stopper, and the electrode tab of the electrode assembly is electrically connected to the housing via the current collecting member. This not only limits the end cap, but also the current collecting member, thereby limiting the movement of the electrode assembly, reducing the amount of displacement of the electrode assembly within the housing along the thickness of the end cap, and lowering the risk of failure of the connection between the electrode tab and the current collecting member due to excessive displacement of the electrode assembly.

[0028] In a possible implementation, the current collecting member is welded to the housing, thereby achieving electrical connection between the current collecting member and the housing by welding.

[0029] In one possible implementation, the negative electrode active material includes at least one of elemental silicon, a silicon-oxygen compound, a silicon-carbon composite, a silicon-nitrogen composite, a silicon-containing alloy, or a silicon-oxygen-carbon composite. These negative electrode active materials have high specific capacities, and their use can help increase the energy density of the battery cell.

[0030] In one possible implementation, based on the total mass of the negative electrode active material, the silicon mass content A in the negative electrode active material satisfies the following: 1 wt% ≤ A ≤ 15 wt%. Alternatively, 2 wt% ≤ A ≤ 8 wt%. Thus, the negative electrode active material has an appropriate silicon mass content, thereby achieving a suitable expansion rate for the electrode assembly and facilitating normal use of the battery cell.

[0031] In a possible implementation, the electrode assembly further includes a positive electrode sheet and a separator, wherein the separator is located between the positive electrode sheet and the negative electrode sheet; the positive electrode sheet includes a positive electrode active material, and the chemical formula of the positive electrode active material satisfies: Li 1+a [Ni x Co y Mn z M b ]O2, M includes at least one of Zr, Al, Ti, Sb, Nb, Te, Mg, B, Ca, V, Ta or Sr, 0.1≥a≥-0.1, 1>x≥0.7, 0.3>y>0, 0.3>z>0, 0.3>b≥0, x+y+z+b=1.

[0032] The positive electrode active material conforming to the above chemical formula has a higher gram capacity, and thus a battery cell prepared using the above positive electrode active material has a higher energy density.

[0033] In a possible implementation, the shell is made of carbon steel or stainless steel. Steel shells are not easily corroded by electrolyte, which helps improve the reliability of the battery cell.

[0034] In a possible implementation, the battery cell is a cylindrical battery cell, so that the shape of the battery cell is compatible with the shape of the current collecting member, facilitating assembly of the battery cell.

[0035] In one possible implementation, the housing includes a cylindrical body and a cover connected to the cylindrical body. The cover and the cylindrical body are integral or separate structures. The cylindrical body is disposed around the periphery of the electrode assembly, and the cover is provided with an electrode lead-out hole. The battery cell also includes an electrode terminal, which is insulated and disposed in the electrode lead-out hole. In this way, one of the housing and the electrode terminal serves as the positive output electrode of the battery cell, and the other serves as the negative output electrode of the battery cell. At least a portion of the housing itself can serve as an output electrode of the battery cell, thereby eliminating an electrode terminal and simplifying the structure of the battery cell.

[0036] In a second aspect, a battery is provided, comprising a battery cell as described in the first aspect and any possible implementation thereof.

[0037] In a third aspect, an electrical device is provided, comprising the battery described in the second aspect.

[0038] In an embodiment of the present application, the current collecting member is located on the side of the electrode assembly facing the end cap and is electrically connected to the electrode tab and the shell of the electrode assembly. In this way, the electrical connection between the electrode assembly and the shell can be achieved through the current collecting member. The negative electrode active material in the battery cell includes silicon, the battery cell has a higher energy density and the electrode assembly in the battery cell expands to a greater extent. The elastic portion in the current collecting member has the ability to elastically deform. When the electrode assembly expands, the elastic portion is compressed to provide space for the expansion of the electrode assembly. Moreover, the deformable elastic portion can weaken the squeezing effect on the electrode assembly compared to the non-deformable rigid component, thereby reducing the risk of the electrode assembly being squeezed, which is beneficial to improving the reliability of the battery cell. Therefore, the technical solution of the embodiment of the present application can take into account both the energy density and reliability of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0040] FIG1 is a schematic structural diagram of a vehicle according to an embodiment of the present application;

[0041] FIG2 is a schematic structural diagram of a battery according to an embodiment of the present invention;

[0042] FIG3 is an exploded schematic diagram of the structure of a battery cell according to an embodiment of the present application;

[0043] FIG4 is a schematic structural diagram of a battery cell according to an embodiment of the present application;

[0044] FIG5 is a cross-sectional view of the battery cell in FIG4 along the AA direction;

[0045] FIG6 is an enlarged schematic diagram of area B in FIG5 ;

[0046] FIG7 is a schematic diagram of an electrode assembly according to an embodiment of the present application;

[0047] FIG8 is a schematic structural diagram of a current collecting component according to an embodiment of the present application;

[0048] FIG9 is a schematic structural diagram of a current collecting component according to an embodiment of the present application;

[0049] FIG10 is a schematic structural diagram of a current collecting component according to an embodiment of the present application;

[0050] FIG11 is a schematic structural diagram of an end cover according to an embodiment of the present application;

[0051] FIG12 is an exploded schematic diagram of the structure of a battery cell according to another embodiment of the present application;

[0052] FIG13 is a schematic structural diagram of a battery cell according to an embodiment of the present application;

[0053] FIG14 is a cross-sectional view of the battery cell along the A'-A' direction in FIG13;

[0054] FIG15 is an enlarged schematic diagram of region C in FIG14 .

[0055] In the drawings, the drawings are not drawn to scale.

[0056] Figure markings: 1: vehicle; 10: battery; 30: controller; 40: motor; 3: housing; 31: first housing; 32: second housing; 20: battery cell; 21: housing; 210: cylinder; 211: cover; 2111: electrode lead-out hole; 22: electrode assembly; 23: end cap; 24: current collecting member; 25: electrode terminal; 26: pressure relief mechanism; 261: notched groove; 240: current collecting body; 241: elastic part; 242: current collecting sheet; 2411: first sheet; 2412: second sheet; 2413: center part; 2414: abutment area; 2415: first through hole; 2401: first gap; 2402: second gap; 231: end cap body; 232: first protrusion. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0058] 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.

[0059] 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.

[0060] 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. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0061] 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.

[0062] 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.

[0063] In the embodiments of this application, identical reference numerals represent identical components, and for the sake of brevity, detailed descriptions of identical components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of 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 do not constitute any limitation on this application.

[0064] The term "multiple" in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0065] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0066] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0067] In some implementations, the battery cell in the embodiment of the present application may be a metal battery. Specifically, the metal battery may include a lithium metal secondary battery, a sodium metal battery, or a magnesium metal battery, etc., which is not limited in the embodiment of the present application.

[0068] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. During the charge and discharge process, active ions (such as lithium ions) move back and forth between the positive and negative electrode sheets. A separator, placed between the positive and negative electrode sheets, prevents short circuits between the positive and negative electrodes while allowing the active ions to pass through.

[0069] In some embodiments, the positive electrode sheet may include a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes a positive electrode active material. Optionally, the positive electrode film layer further includes a conductive agent and a binder.

[0070] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active membrane layer is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0071] As an example, the positive electrode current collector can be a metal foil, a foamed metal 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 foamed metal can be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. The composite current collector may include a polymer material base and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0072] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. 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.

[0073] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material. Optionally, the negative electrode film layer includes a conductive agent and a binder.

[0074] As an example, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0075] As an example, the negative electrode current collector may be a metal foil, a metal foam, or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. may be used. The composite current collector may include a polymer material base layer and a metal layer. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, etc. The composite current collector may 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.).

[0076] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode sheet and the negative electrode sheet.

[0077] 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.

[0078] As an example, the main material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] The battery mentioned in the embodiments of the present application may include one or more battery cells to provide a single physical module with higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in hybrid through a busbar.

[0084] In some embodiments, the battery may be a battery pack, which may include a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0085] 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.

[0086] In some embodiments, the battery may be located in an energy storage device, such as an energy storage container or an energy storage cabinet.

[0087] The development of battery technology requires simultaneous consideration of multiple design factors, such as energy density, cycle life, discharge capacity, charge / discharge rate, and reliability. In some configurations, silicon-containing materials are selected as the negative electrode active material in the preparation of battery cells to increase their energy density. However, while these battery cells have a high energy density, the high expansion rate of the silicon-containing material exacerbates the expansion problem during use. Therefore, providing a battery cell that reduces the adverse effects of the high expansion rate on the battery cell while balancing its energy density and reliability is a pressing technical challenge.

[0088] In light of this, embodiments of the present application provide a battery cell comprising a silicon-containing negative electrode active material. A current collecting member in the battery cell includes an elastic portion protruding from the current collecting body, the elastic portion abutting against an end cap of the battery cell. Because the elastic portion is elastically deformable, it can be compressed during expansion of the electrode assembly, providing a buffer for the electrode assembly's expansion and reducing the risk of compression, thereby balancing the energy density and reliability of the battery cell.

[0089] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use batteries.

[0090] Electrically powered devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and power tools. Vehicles may include fuel-powered vehicles, gas-powered vehicles, or new energy vehicles. New energy vehicles may include pure electric vehicles, hybrid vehicles, or extended-range vehicles. Spacecraft include aircraft, rockets, space shuttles, and spacecraft. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. The present application does not impose any specific restrictions on the aforementioned electrical devices.

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

[0092] For example, as shown in FIG1 , which is a structural diagram of a vehicle according to an embodiment of the present application, the vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A motor 40, a controller 30 and a battery 10 may be provided inside the vehicle 1, and the controller 30 is used to control the battery 10 to power the motor 40. For example, a battery 10 may be provided at the bottom, front or rear of the vehicle 1. The battery 10 may be used to power the vehicle 1, for example, the battery 10 may be used as an operating power source for the vehicle 1, for the circuit system of the vehicle 1, for example, for the working power requirements during the start-up, navigation and operation of the vehicle 1. In another embodiment of the present application, the battery 10 may not only be used as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0093] In order to meet different power requirements, the battery 10 may include multiple battery cells. According to different power requirements, the number of battery cells 20 can be set to any value. Multiple battery cells 20 can be connected in series, parallel or mixed to achieve a larger capacity or power. Since the number of battery cells 20 included in each battery 10 may be large, for ease of installation, the battery cells 20 can be grouped, and each group of battery cells 20 constitutes a battery module. The number of battery cells 20 included in the battery module is not limited and can be set according to requirements. The battery may include multiple battery modules, which can be connected in series, parallel or mixed.

[0094] For example, as shown in FIG2 , which is a schematic structural diagram of a battery according to an embodiment of the present application, the battery 10 may include a plurality of battery cells 20. The battery 10 may also include a casing 3, the interior of the casing 3 being a hollow structure, and the plurality of battery cells 20 being accommodated in the casing 3. For example, the plurality of battery cells 20 are connected in parallel, in series, or in a mixed combination and placed in the casing 3. The casing 3 may include a first casing 31 and a second casing 32, which cover each other to form the casing 3. The first casing 31 and the second casing 32 may both be hollow structures with an opening at one end; or the first casing 31 may be a plate-like structure, and the second casing 32 may be a hollow structure with an opening at one end.

[0095] Optionally, the battery 10 may also include other structures, which will not be described in detail here. For example, the battery 10 may also include a busbar component, which is used to achieve electrical connection between multiple battery cells 20, such as parallel connection, series connection, or mixed connection. Specifically, the busbar component can achieve electrical connection between the battery cells 20 by connecting the electrode terminals of the battery cells 20. Furthermore, the busbar component can be fixed to the electrode terminals of the battery cells 20 by welding. The electrical energy of the multiple battery cells 20 can be further led out through the box 3 through the conductive mechanism. Optionally, the conductive mechanism may also belong to the busbar component.

[0096] Figure 3 is an exploded schematic diagram of the structure of a battery cell according to an embodiment of the present application, Figure 4 is a schematic diagram of a battery cell according to an embodiment of the present application, Figure 5 is a cross-sectional view of the battery cell along the AA direction in Figure 4, and Figure 6 is an enlarged schematic diagram of area B in Figure 5.

[0097] In one embodiment of the present application, for example, as shown in FIG. 3 to FIG. 6 , the battery cell 20 includes: a housing 21 , an electrode assembly 22 , an end cover 23 and a current collecting member 24 .

[0098] The case 21 is provided with an opening, and is used to accommodate the electrode assembly 22 and the current collecting member 24 .

[0099] The housing 21 may be a hollow structure with an opening at one end or a hollow structure with openings at both ends. As an example, as shown in FIG3 , the housing 21 is a hollow structure with an opening at one end, and the end cap 23 is used to cover the opening of the housing 21 .

[0100] The housing 21 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The housing 21 can be in various shapes, such as a cylinder, a cuboid, etc. As an example, in the embodiment of the present application, the housing 21 is made of steel and is cylindrical.

[0101] The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. The electrode assembly 22 includes a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer. The positive electrode film layer is coated on the surface of the positive electrode current collector. The current collector not coated with the positive electrode film layer protrudes from the current collector coated with the positive electrode film layer. The current collector not coated with the positive electrode film layer serves as the positive electrode tab. The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer. The negative electrode film layer is coated on the surface of the negative electrode current collector. The current collector not coated with the negative electrode film layer protrudes from the current collector coated with the negative electrode film layer. The current collector not coated with the negative electrode film layer serves as the negative electrode tab. The positive electrode sheet, separator, and negative electrode sheet can be formed into the electrode assembly 22 by winding or stacking.

[0102] As an example, the positive electrode sheet, separator, and negative electrode sheet are wound into an electrode assembly 22. In the wound electrode assembly 22, the area provided with the positive electrode film layer and / or the negative electrode film layer can be referred to as the main body of the electrode assembly 22, and the area not provided with the positive electrode film layer and the negative electrode film layer is referred to as the tab of the electrode assembly 22. Figure 7 is a schematic diagram of an electrode assembly according to an embodiment of the present application. For example, as shown in Figure 7, the electrode assembly 22 includes a tab 221 and a main body 222. Along the axial direction of the cylindrical electrode assembly 22 (e.g., the z direction in Figure 7), the tab 221 is closer to the current collecting member 24 than the main body 222.

[0103] The negative electrode plate includes a negative electrode current collector and a negative electrode film layer arranged on at least one side surface of the negative electrode current collector. The negative electrode film layer includes a negative electrode active material that can reversibly extract and embed metal ions. The negative electrode active material includes silicon.

[0104] Metal ions can reversibly be extracted from or reversibly embedded in the negative electrode active material. As an example, in a lithium-ion battery cell, lithium ions can reversibly be embedded in or extracted from the negative electrode active material. As another example, in a sodium-ion battery cell, sodium ions can reversibly be embedded in or extracted from the negative electrode active material.

[0105] The negative electrode active material includes silicon. For example, the negative electrode active material can be a silicon-based material.

[0106] Optionally, the negative electrode active material further includes carbon, for example, the negative electrode active material is a silicon-carbon composite material.

[0107] In addition to the negative electrode active material, the negative electrode film layer may also include a conductive agent and a binder. As an example, during the preparation of the negative electrode sheet, the negative electrode active material, the conductive agent, and the binder are mixed to form a slurry, which is then coated on the negative electrode current collector to form the negative electrode film layer.

[0108] The end cap 23 is used to cover the opening of the housing 21 to isolate the internal environment of the battery cell 20 from the external environment. The end cap 23 covers the opening of the housing 21 and together with the housing 21 define a sealed space for accommodating the electrode assembly 22, electrolyte, and current collecting member 24.

[0109] The shape of the end cap 23 can be compatible with the shape of the housing 21. For example, if the housing 21 is a rectangular parallelepiped structure, the end cap 23 can be a rectangular plate-shaped structure that matches the housing 21. For another example, if the housing 21 is a cylindrical structure, the end cap 23 can be a circular plate-shaped structure that matches the housing 21. The end cap 23 can also be made of various materials. For example, the end cap 23 can be made of a metal material such as copper, iron, aluminum, steel, or an aluminum alloy. The material of the end cap 23 can be the same as or different from that of the housing 21. As an example, the material of the end cap 23 is copper.

[0110] In the battery cell 20, there can be one or two end caps 23. If the housing 21 is a hollow structure with an opening at one end, one end cap 23 is provided accordingly; if the housing 21 is a hollow structure with openings at both ends, two end caps 23 are provided accordingly. The two end caps 23 respectively cover the two openings of the housing 21. One of the positive and negative tabs of the electrode assembly 22 is electrically connected to one end cap 23, and the other is electrically connected to the housing 21. In the embodiment where the housing 21 is a hollow structure with an opening at one end, an electrode terminal 25 can be provided at the end of the housing 21 facing away from the end cap 23. The electrode terminal 25 is insulated from the housing 21. One of the positive and negative tabs of the electrode assembly 22 is electrically connected to the housing 21, and the other is electrically connected to the electrode terminal 25.

[0111] The current collecting member 24 is housed within the housing 21 and is located on the side of the electrode assembly 22 facing the end cap 23. The current collecting member 24 is electrically connected to the electrode assembly 22 and the housing 21. Thus, the housing 21 serves as an output terminal of the battery cell 20. Specifically, the current collecting member 24 is electrically connected to the tab 221 of the electrode assembly 22 and the housing 21.

[0112] The current collecting member 24 can be a disc-shaped member disposed between the end cap 23 and the electrode assembly 22. For example, the housing 21 is cylindrical and the current collecting member 24 is a disc structure. The current collecting member 24 can be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc.

[0113] Figure 8 is a schematic diagram of the structure of a current collecting component according to an embodiment of the present application, Figure 9 is a schematic diagram of the structure of a current collecting component according to an embodiment of the present application, and Figure 10 is a schematic diagram of the structure of a current collecting component according to an embodiment of the present application. Figures 8 to 10 are schematic diagrams of the structure of the current collecting component from different perspectives.

[0114] As shown in Figures 7 to 10, the current collecting component 24 includes a current collecting body 240 and an elastic portion 241. The current collecting body 240 is an annular structure. The elastic portion 241 is located on the inner side of the current collecting body 240 and is connected to the current collecting body 240. At least part of the elastic portion 241 protrudes from the current collecting body 240 along the thickness direction of the end cover 23 and abuts against the end cover 23.

[0115] Along the thickness direction of the end cover 23 , the elastic portion 241 protrudes relative to the current collecting body 240 in a direction away from the electrode assembly 22 and abuts against the end cover 23 .

[0116] Along the thickness direction of the end cap 23, the elastic portion 241 may partially protrude from the current collecting body 240 and abut against the end cap 23, or may completely protrude from the current collecting body 240 and abut against the end cap 23. By providing that the elastic portion 241 at least partially protrudes from the current collecting body 240 along the thickness direction of the end cap 23, the abutment of the elastic portion 241 and the end cap 23 is facilitated.

[0117] When the negative active material in the negative electrode sheet includes silicon, the negative active material can accommodate more metal ions, effectively increasing the energy density of the battery cell. Furthermore, this can increase the deformation of the electrode assembly 22 within the battery cell during use. In particular, during charging of the battery cell, metal ions embedding in the negative active material of the negative electrode sheet can cause the electrode assembly 22 to expand in volume, thereby increasing the pressure exerted by the electrode assembly 22 on the end cap 23 of the battery cell. By providing the elastic portion 241, the deformable elastic portion 241 can reduce the compressive effect on the electrode assembly 22 compared to a non-deformable rigid component. Furthermore, the elastic portion 241 can be compressed, thereby providing space for the electrode assembly 22 to expand.

[0118] During the assembly of the battery cell 20, a compressive force can be applied between the current collecting member 24 and the end cap 23. After the battery cell 20 is assembled, the elastic portion 241 of the current collecting member 24 abuts against the end cap 23. The elastic portion 241 is elastically deformable. When the electrode assembly 22 expands, the elastic portion 241 can be compressed, thereby providing a buffer for the expansion of the electrode assembly 22 and reducing the risk of the electrode assembly 22 being squeezed. Furthermore, compared to non-deformable rigid components, the deformable elastic portion 241 can weaken the squeezing effect on the electrode assembly 22, thereby further reducing the risk of the electrode assembly 22 being squeezed, reducing the risk of powder loss and lithium deposition caused by squeezing the electrode assembly 22, and improving the reliability of the battery cell.

[0119] Furthermore, since the elastic portion 241 is in tight contact with the end cap 23 when the battery cell 20 is assembled, the elastic portion 241 can still contact the end cap 23 even if the electrode assembly 22 contracts during the subsequent charge and discharge process of the battery cell 20 .

[0120] In this embodiment of the present application, the current collecting member 24 is located on the side of the electrode assembly 22 facing the end cap 23 and is connected to the electrode assembly 22 and the housing 21. This allows for electrical connection between the electrode assembly 22 and the housing 21 via the current collecting member 24. The negative electrode active material includes silicon, and the battery cell 20 has a high energy density. Furthermore, the electrode assembly 22 within the battery cell 20 expands more rapidly. The elastic portion 241 in the current collecting member 24 is elastically deformable. When the electrode assembly 22 expands, the elastic portion 241 is compressed, providing space for the electrode assembly 22 to expand, thereby reducing the risk of the electrode assembly 22 being squeezed. Furthermore, the deformable elastic portion 241, compared to a non-deformable rigid component, can weaken the squeezing effect on the electrode assembly 22, further reducing the risk of squeezing the electrode assembly 22 and the risk of powder loss and lithium deposition caused by squeezing, thereby improving the reliability of the battery cell. Therefore, the technical solutions of this embodiment of the present application help improve the reliability of the battery cell 20.

[0121] In some embodiments, the elastic portion 241 can be deformed during the charge and discharge process of the battery cell.

[0122] During the charge and discharge process of the battery cell, the electrode assembly 22 expands and contracts. When the electrode assembly 22 expands, the elastic portion 241 can be compressed to provide space for the expansion of the electrode assembly 22; when the electrode assembly 22 contracts, the elastic portion 241 can return from the compressed state to the uncompressed state (or from a more compressed state to a less compressed state).

[0123] In this embodiment, the elastic portion 241 can deform during the charge and discharge process of the battery cell, thereby providing space for the expansion of the electrode assembly 22; and when the electrode assembly 22 contracts, it is also beneficial for the elastic portion 241 to return to its original state.

[0124] In some embodiments, the end cover 23 is provided with a first protrusion 232 . The first protrusion 232 protrudes toward the electrode assembly 22 along the thickness direction of the end cover 23 . The first protrusion 232 abuts against the elastic portion 241 .

[0125] In the above technical solution, the provision of the first protrusion 232 is conducive to improving the strength of the end cover 23 , and the abutment between the first protrusion 232 and the elastic portion 241 is also conducive to reducing the size of the elastic portion 241 protruding from the current collecting body 240 .

[0126] In some embodiments, the current collecting member 24 further includes a central portion 2413 located inside the elastic portion 241 .

[0127] Because the current collecting body 240 is annular in structure, the elastic portion 241 is located inside the current collecting body 240 and connected to the current collecting body 240, and the central portion 2413 is located inside the elastic portion 241. Thus, the central portion 2413 is substantially the central area of ​​the current collecting member 24. Since the current collecting member 24 is electrically connected to the tab 221, the central portion 2413 substantially corresponds to the central area of ​​the tab 221 of the electrode assembly 22.

[0128] As an example, the central portion 2413 is connected to the elastic portion 241 , so that the central portion 2413 , the elastic portion 241 and the current collecting body 240 can be connected to form a whole.

[0129] As an example, when the electrode assembly 22 expands, the central portion 2413 abuts against the tab 221 .

[0130] As another example, when the electrode assembly 22 is contracted, a gap exists between the central portion 2413 and the tab 221 .

[0131] As an example, during the charge and discharge process of the battery cell, the central portion 2413 always contacts the tab 221 .

[0132] In this embodiment, the elastic portion 241 is located between the central portion 2413 and the current collecting body 240 , and the central portion 2413 corresponds to the central area of ​​the tab 221 of the electrode assembly 22 , thereby providing a certain support for the tab 221 .

[0133] The central portion 2413 may have a disc-shaped structure or an irregular sheet-shaped structure.

[0134] As an example, a through hole penetrating the central portion 243 is provided on the central portion 243 , so that the central portion 243 is weaker and more easily broken when thermal runaway occurs in the battery cell 20 .

[0135] In some embodiments, the central portion 2413 abuts against the tab 221 of the electrode assembly 22. In this way, the central portion 2413 can provide a certain support for the tab 221, which is beneficial for reducing the shaking of the electrode assembly 22 in the housing 21.

[0136] In addition, when the central portion 2413 is connected to the elastic portion 241 , deformation of the elastic portion 241 can drive the central portion 2413 to move, thereby reducing the risk of the central portion 2413 severely squeezing the tab 221 when the electrode assembly 22 expands.

[0137] In some embodiments, the elastic portion 241 includes a first piece 2411 and a second piece 2412, the first piece 2411 is connected to the inner side of the current collecting body 240 and extends obliquely toward the end cover 23, the second piece 2412 is connected to the outer side of the central portion 2413 and extends obliquely toward the end cover 23, the first piece 2411 and the second piece 2412 are connected at an angle greater than 0° and less than 180° and form a contact area 2414, and the contact area 2414 abuts against the end cover 23.

[0138] The angle between the first piece 2411 and the second piece 2412 can be 10°, 20°, 30°, 60°, 80°, 90°, 100°, 120°, 160° or any value within the above range.

[0139] As an example, the first piece 2411 and the second piece 2412 are both strip-shaped structures. As another example, the first piece 2411 is a strip-shaped structure, and the second piece 2412 is a ring-shaped structure.

[0140] As an example, along the thickness direction of the end cover 23, the current collecting body 240 and the central portion 2413 are flush. In other words, the current collecting body 240 and the central portion 2413 are on the same plane.

[0141] The first sheet 2411 and the second sheet 2412 both protrude relative to the central portion 2413 toward the end cap 23. The connection between the first sheet 2411 and the second sheet 2412 forms an abutment area 2414, which abuts the end cap 23. When the electrode assembly 22 expands, the electrode assembly 22 expands toward the end cap 23, causing the electrode assembly 22 to press against the central portion 2413. The central portion 2413 moves toward the end cap 23, which in turn drives the first sheet 2411 and the second sheet 2412 to move toward the end cap 23. The elastic portion 241 elastically deforms, thereby providing space for the expansion of the electrode assembly 22.

[0142] In the above technical solution, the center portion 2413 abuts against the electrode assembly 22, the abutment area 2414 formed by connecting the first sheet 2411 and the second sheet 2412 abuts against the end cover 23, and the elastic portion 241 has the ability of elastic deformation. In this way, during the expansion of the electrode assembly 22, the abutment area 2414 is compressed to provide space for the expansion of the electrode assembly 22, and the center portion 2413 can play a softer supporting role for the electrode assembly 22, which can reduce the strength of the extrusion of the electrode assembly 22, thereby reducing the risks of powder loss, lithium precipitation, etc. caused by excessive extrusion of the electrode assembly 22.

[0143] In some embodiments, the end cap 23 includes an end cap body 231 and a first protrusion 232 . The first protrusion 232 protrudes toward the electrode assembly 22 along the thickness direction of the end cap 23 . The first protrusion 232 abuts against the abutment area 2414 .

[0144] The end cover body 231 may be a plate-shaped structure. As an example, the end cover body 231 is a circular plate-shaped structure.

[0145] The first protrusion 232 may be a protrusion provided on the end cover body 231 . For example, the first protrusion 232 is a protrusion provided on the end cover body 231 , and the protrusion protrudes toward the electrode assembly 22 .

[0146] The provision of the first protrusion 232 is beneficial to improving the strength of the end cover 23 and also beneficial to reducing the distance between the end cover 23 and the abutment area 2414 along the thickness direction of the end cover 23, thereby facilitating the abutment between the end cover 23 and the abutment area 2414 of the elastic portion 241.

[0147] In some embodiments, the elastic portion 241 is provided with a first through hole 2415 penetrating the elastic portion 241 along a thickness direction of the elastic portion 241 , and the first through hole 2415 extends from the first piece 2411 to the second piece 2412 .

[0148] As an example, the first through hole 2415 may be in the shape of an elongated strip. Alternatively, the first through hole 2415 may also be in the shape of a circle, a triangle, or an irregular shape.

[0149] Optionally, independent first through holes 2415 may be provided on the first sheet 2411 and the second sheet 2412 , respectively. The embodiments of the present application include but are not limited to this.

[0150] The provision of the first through hole 2415 facilitates deformation of the elastic portion 241, thereby further reducing the risk of compression of the electrode assembly 22. In addition, the provision of the first through hole 2415 facilitates the discharge of high-temperature and high-pressure substances inside the battery cell 20 when thermal runaway occurs.

[0151] In some embodiments, there are multiple elastic portions 241 , and each elastic portion 241 is arranged at intervals along the circumference of the current collecting body 240 .

[0152] As an example, the first sheet 2411 and the second sheet 2412 are both strip-shaped structures. The current collecting member 24 includes a plurality of first sheets 2411 and a plurality of second sheets 2412. The plurality of first sheets 2411 and the plurality of second sheets 2412 are spaced apart along the circumference of the current collecting body 240. As an example, the current collecting member 24 includes three first sheets 2411 and three second sheets 2412.

[0153] As another example, the first sheet 2411 is a strip-shaped structure, the second sheet 2412 is annular, and the current collecting member 24 includes multiple first sheets 2411 and one second sheet 2412. The multiple first sheets 2411 are spaced apart along the circumference of the second sheet 2412 and connected to the second sheet 2412. The multiple first sheets 2411 are also spaced apart along the circumference of the current collecting body 240. As an example, the current collecting member 24 includes three first sheets 2411 and one second sheet 2412.

[0154] As an example, there are three elastic portions 241 , and the angle between two adjacent elastic portions 241 is 120°.

[0155] The presence of multiple elastic portions 241 makes their distribution within the current collecting member 24 more uniform, resulting in more uniform deformation of the multiple elastic portions 241. This helps to more evenly alleviate the compressive forces exerted on the electrode assembly 22 and reduces the risk of varying degrees of compression in different areas of the electrode assembly 22. Furthermore, the spacing between adjacent elastic portions 241 facilitates the formation of a smoother venting channel, facilitating the discharge of high-temperature, high-pressure materials within the battery cells 20 during thermal runaway.

[0156] In some embodiments, the current collecting component 24 also includes a current collecting piece 242 connected to the current collecting body 240, and a current collecting piece 242 is provided between two adjacent elastic parts 241. The side surface of the current collecting piece 242 facing away from the end cover 23 is connected to the electrode ear of the electrode assembly 22, and the current collecting piece 242 and the elastic part 241 are spaced apart.

[0157] As an example, a current collecting piece 242 is provided between two adjacent first pieces 2411. The current collecting piece 242 is spaced apart from the first piece 2411, and the current collecting piece 241 is spaced apart from the second piece 2412. For example, a second gap 2402 is provided between the current collecting piece 242 and the second piece 2412 of the elastic portion 241, and a first gap 2401 is provided between the current collecting piece 242 and the first piece 2411 of the elastic portion 241. The second gap 2402 may be a through hole extending through the current collecting member 24, and the first gap 2401 may be a through hole extending through the current collecting member 24.

[0158] The current collecting sheet 242 has two surfaces facing each other along its thickness direction, wherein the surface of the current collecting sheet 242 facing the electrode assembly 22 (also referred to as the surface facing away from the end cap 23) is connected to the electrode tab 221 of the electrode assembly 22. Specifically, the current collecting sheet 242 can be connected to the electrode tab 221 by welding.

[0159] The current collecting piece 242 may have a fan-shaped structure, so that the shape of the current collecting piece 242 is compatible with the shapes of the current collecting body 240 and the elastic member 241 .

[0160] In the above technical solution, the surface of the current collecting sheet 242 facing away from the end cap 23 is connected to the electrode assembly 22. In this way, the current of the electrode assembly 22 can be transmitted to the housing through the current collecting sheet 242. The current collecting sheet 242 is spaced apart from the elastic portion 241. In this way, the gap between the current collecting sheet 242 and the elastic portion 241 can form a smooth exhaust channel, which facilitates the smooth discharge of emissions from the battery cell 2020. In addition, the gap between the current collecting sheet 242 and the elastic portion 241 allows the current collecting sheet 242 to move relative to the current collecting body 240, which helps reduce the risk of the electrode assembly 22 being squeezed or torn.

[0161] In some embodiments, the current collecting member 24 includes a current collecting body 240, an elastic portion 241, a central portion 2413, and a current collecting piece 242. The current collecting piece 242 and the elastic portion 241 are both connected to the annular current collecting body 240, the central portion 2413 is connected to the elastic portion 241 and is located inside the elastic portion 241, and the elastic portion 241 is spaced apart from the current collecting piece 242. Thus, the central portion 2413 and the elastic portion 241 are connected as a whole, and the elastic portion 241 and the current collecting piece 242 are both connected to the current collecting body 240, thereby forming the current collecting member 24.

[0162] In some embodiments, at least one current collecting piece 242 is welded to the tab 221 of the electrode assembly 22 to form a plurality of welds 2421. The plurality of welds 2421 are spaced apart along the circumference of the current collecting body 240. The provision of the plurality of welds 2421 facilitates enhancing the connection strength between the tab 221 and the current collecting piece 242.

[0163] As an example, the welding portion 2421 may be a weld mark formed by welding the current collecting piece 242 and the tab 221 .

[0164] As an example, the current collecting member 24 includes three current collecting pieces 242 . The three current collecting pieces 242 are welded to the tabs 221 to form three welding portions 2421 . The three welding portions 2421 are spaced apart along the circumference of the current collecting body 240 .

[0165] As an example, the welding portion 2421 has an elliptical structure.

[0166] In some embodiments, the welding portion 2421 includes a first welding portion 24211 and two second welding portions 24212. The first welding portion 24211 is located between the two second welding portions 24212, and the length of the first welding portion 24211 is greater than the length of the second welding portion 24212. In this way, the arrangement of the first welding portion 24211 and the second welding portion 24212 is adapted to the shape of the current collecting piece 242, facilitating welding between the welding portion 2421 and the current collecting piece 242.

[0167] In some embodiments, the end cover 23 includes an end cover body 231 and a pressure relief mechanism 26 . The pressure relief mechanism 26 is located inside the end cover body 231 , and the elastic portion 241 abuts against the pressure relief mechanism 26 .

[0168] The pressure relief mechanism 26 is a component or element that is activated when the pressure or temperature within the battery cell 20 reaches a predetermined threshold, thereby releasing the pressure or temperature within the battery cell 20. This predetermined threshold can be adjusted based on different design requirements. For example, the predetermined threshold may depend on the material of one or more of the positive electrode sheet, negative electrode sheet, electrolyte, and separator in the battery cell.

[0169] "Actuation" means that the pressure relief mechanism 26 is activated or activated to a certain state, thereby allowing the internal pressure and temperature of the battery cell 20 to be released. The action produced by the pressure relief mechanism 26 may include, but is not limited to: at least a portion of the pressure relief mechanism 26 is ruptured, broken, torn, or opened, etc. When the pressure relief mechanism 26 is actuated, the high-temperature and high-pressure substances inside the battery cell 20 are discharged outward from the actuated part as exhaust. In this way, the pressure and temperature of the battery cell 20 can be relieved under controllable pressure or temperature, thereby reducing the risk of potentially more serious accidents.

[0170] The emissions from the battery cells 20 mentioned in the embodiments of the present application include but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, fragments of the current collecting components 24, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0171] The pressure relief mechanism 26 can be a separate structure from the end cover 23. For example, the pressure relief mechanism 26 is an independent component installed on the end cover 23. The pressure relief mechanism 26 can be a component such as an explosion-proof valve, explosion-proof disk, air valve, pressure relief valve, or safety valve installed on the end cover 23, and can specifically adopt a pressure-sensitive or temperature-sensitive element or structure.

[0172] The pressure relief mechanism 26 can be an integral structure with the end cover 23. For example, the pressure relief mechanism 26 is a part of the end cover 23. For example, the pressure relief mechanism can be formed by providing a notch on the end cover 23, and the thickness of the notch is significantly smaller than the thickness of other areas of the end cover 23. The notch is the weakest position of the pressure relief mechanism. When the battery cell 20 generates too much gas, causing the internal pressure to rise and reach a threshold, or when the internal reaction of the battery cell 20 generates heat, causing the internal temperature of the battery cell 20 to rise and reach a threshold, the pressure relief mechanism 26 can rupture at the notch, causing the inside and outside of the battery cell 20 to communicate with each other, and the gas pressure and temperature are released outward through the rupture of the pressure relief mechanism 26, thereby preventing the battery cell 20 from exploding. As an example, a notch groove is provided on the end cover 23, and the area defined by the notch groove forms the pressure relief mechanism 26.

[0173] In the above technical solution, the pressure relief mechanism 26 is located on the inner side of the end cover body 231, which can reduce the risk of the pressure relief mechanism 26 interfering with components outside the battery cell 2020 and being damaged, and is beneficial to improving the long-term reliability of the pressure relief mechanism 26; the elastic part 241 abuts against the pressure relief mechanism 26, facilitating the connection between the elastic part 241 and the end cover 23.

[0174] As an example, the abutment area 2411 of the elastic portion 241 abuts against the pressure relief mechanism 26, thereby facilitating abutment between the elastic portion 241 and the end cap 23. Furthermore, when the pressure relief mechanism 26 is actuated, exhaust within the battery cell 20 is facilitated to be discharged through the exhaust passages (e.g., the first and second spacers 2401, 2402) formed by the current collecting member 24.

[0175] In some embodiments, the pressure relief mechanism 26 is provided with a first protrusion 232, which protrudes toward the electrode assembly 22 along the thickness direction of the end cap 23. The first protrusion 232 abuts against the abutment area 2414 of the elastic portion 241. In this way, the connection between the elastic portion 241 and the end cap 23 is achieved.

[0176] As an example, a first protrusion 232 is provided within the area defined by the pressure relief mechanism 26, and the first protrusion 232 abuts against the abutment area 2414 of the elastic portion 241. Thus, the position of the first protrusion 232 corresponds to the abutment area 2414, and the first protrusion 232 is farther from the edge of the end cap 23, facilitating the processing of the first protrusion 232.

[0177] Figure 11 is a schematic diagram of the structure of an end cap according to one embodiment of the present application. In some embodiments, for example, as shown in conjunction with Figures 7 and 11 , end cap 23 is provided with a notched groove 261. The area defined by notched groove 261 forms pressure relief mechanism 26. First protrusion 232 is located inside notched groove 261 and spaced apart from it.

[0178] As an example, the notched groove 261 is annular with a gap. The thickness of the region of the end cap 23 provided with the notched groove 261 is smaller than the thickness of the region not provided with the notched groove 261. Therefore, when thermal runaway occurs, the notched groove 261 of the end cap 23 is more likely to rupture.

[0179] In the above embodiment, the first protrusion 232 is spaced apart from the notched groove 261, which facilitates the preparation of the notched groove 261 and reduces the adverse effects on the accuracy of the notched groove 261. In addition, the setting of the notched groove 261 is also beneficial in reducing the risk of interference between the pressure relief mechanism 26 and structures outside the battery cell 20.

[0180] In some embodiments, the current collecting member 24 is welded to the housing 21. The current collecting member 24 can be directly welded to the housing 21, or can be welded to the housing 21 through a special structure provided on the current collecting member 24.

[0181] Figure 12 is a schematic exploded view of the structure of a battery cell according to another embodiment of the present application, Figure 13 is a schematic view of the structure of a battery cell according to another embodiment of the present application, Figure 14 is a cross-sectional view of the battery cell in Figure 13 along the A'-A' direction, and Figure 15 is an enlarged schematic view of area C in Figure 14.

[0182] In some embodiments, as shown in Figures 12 to 15, a limiting portion 211 is convexly provided on the inner side surface of the shell 21, and the current collecting component 24 abuts against the limiting portion 211. The tab 221 of the electrode assembly 22 is electrically connected to the shell 21 through the current collecting component 24.

[0183] The inner side surface of the housing 21 refers to the inner surface of the side wall of the housing 21 extending along the thickness direction of the end cap 23. It is understood that the inner side surface extends substantially along the thickness direction of the end cap 23. In embodiments where the housing 21 is cylindrical, the inner side surface of the housing 21 is a cylindrical surface. In embodiments where the housing 21 is a rectangular parallelepiped, the inner side surface of the housing 21 includes four side surfaces located in different directions and connected end to end.

[0184] The inner side surface of the shell 21 is provided with a limiting portion 211. It is understood that the limiting portion 211 protrudes from the inner side surface. The limiting portion 211 is a structure of the shell 21 that limits the end cover 23 from moving in the direction close to the electrode assembly 22. The current collecting member 24 abuts against the side of the limiting portion 211 facing the electrode assembly 22, and the current collecting member 24 is located on the side of the electrode assembly 22 facing the end cover 23. It is understood that in the thickness direction of the end cover 23, the limiting portion 211 is located between the electrode assembly 22 and the end cover 23. The limiting portion 211 and the shell 21 can be an integrally formed structure, or a structure that is formed separately and then connected together, for example, the limiting portion 211 is welded to the shell 21. The limiting portion 211 can have various structures, for example, the limiting portion 211 is a boss protruding from the inner side surface of the shell 21, and for example, the limiting portion 211 is an annular structure extending along the circumference of the shell 21.

[0185] By setting the limiting portion 211, not only the end cover 23 can be limited, but also the current collecting component 24 can be limited, so that the current collecting component 24 can limit the movement of the electrode assembly 22, reducing the displacement of the electrode assembly 22 in the shell 21 along the thickness direction of the end cover 23, and reducing the risk of failure of the connection between the electrode lug of the electrode assembly 22 and the current collecting component 24 due to excessive displacement of the electrode assembly 22.

[0186] In some embodiments, the end cover 23 is connected to the housing 21 by welding.

[0187] In some embodiments, the battery cell 20 further includes a current collecting plate 27. This current collecting plate 27 can have a different structure than the current collecting member 24 and can be a circular disc. The current collecting plate 27 and the current collecting member 24 are located at opposite ends of the housing 21 and connected to electrodes of opposite polarity. For example, the current collecting plate 27 is connected to the positive electrode tab, while the current collecting member 24 is connected to the negative electrode tab.

[0188] In some embodiments, the battery cell 20 further includes an insulating member 28 , which is used to isolate the electrode terminal 25 from the housing 21 .

[0189] In some embodiments, the negative electrode active material includes at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, silicon-containing alloys, or silicon-oxygen-carbon composite materials. In this way, the battery cell can have a higher energy density.

[0190] In some embodiments, the mass content A of silicon in the negative electrode active material, based on the total mass of the negative electrode active material, satisfies the following: 1 wt% ≤ A ≤ 15 wt%; alternatively, 2 wt% ≤ A ≤ 8 wt%. For example, A is 1 wt%, 2 wt%, 3 wt%, 6 wt%, 8 wt%, 15 wt%, or any value within the foregoing ranges.

[0191] In addition to the negative electrode active material, the negative electrode film layer may optionally include a conductive agent and a binder.

[0192] As an example, the conductive agent in the negative electrode film layer may include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0193] As an example, the binder in the negative electrode film layer may include one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA) and carboxymethyl chitosan (CMCS).

[0194] In some embodiments, the negative electrode active material may further include other additives, such as thickeners, such as sodium carboxymethyl cellulose (CMC), PTC thermistor materials, and the like.

[0195] As an example, the quality of silicon in the negative electrode active material can be measured by inductively coupled plasma emission spectroscopy (ICP).

[0196] In the negative electrode active material, the silicon element has an appropriate mass content, so that the electrode assembly 22 has a relatively appropriate expansion rate, which facilitates the normal use of the battery cell 20.

[0197] In some embodiments, the positive electrode sheet includes a positive electrode active material, the chemical formula of the positive electrode active material satisfies: Li 1+a [Ni x Co y Mn z M b ]O2, M includes at least one of Zr, Al, Ti, Sb, Nb, Te, Mg, B, Ca, V, Ta or Sr, 0.1≥a≥-0.1, 1>x≥0.7, 0.3>y>0, 0.3>z>0, 0.3>b≥0, x+y+z+b=1.

[0198] a may be -0.1, -0.04, 0, 0.04, 0.1 or any value within the above ranges, x may be 0.7, 0.75, 0.8, 0.9, 0.95, 0.96 or any value within the above ranges, y may be 0.1, 0.2 or any value within the above ranges, z may be 0.1, 0.2 or any value within the above ranges, and b may be 0, 0.1, 0.2 or any value within the above ranges. As an example, b is 0, and the positive electrode active material includes LiNi 0.8 Co 0.1 Mn 0.1 As another example, b>0, the positive electrode active material includes LiNi 0.7 Co 0.1 Mn 0.1 Al 0.1 O2.

[0199] Positive electrode active materials that satisfy the above chemical formula are called high-nickel ternary materials. Combining high-nickel ternary materials with silicon-containing negative electrode active materials can help improve the energy density of battery cells. Furthermore, compared to ternary materials with lower nickel content or materials such as lithium iron phosphate, high-nickel ternary materials have higher gram capacity. Therefore, at the same capacity, using high-nickel ternary materials can help reduce the total mass of the positive electrode active material, thereby further improving the energy density of the battery cells.

[0200] It should be noted that the battery cells are accompanied by Li deintercalation and consumption during the charge and discharge process, and the molar content of Li in the battery cells is different when discharged to different states. In the examples of the present application, the molar content of Li in the list of positive electrode active materials is the initial state of the material. The positive electrode active materials are used in the battery system, and the molar content of Li will change after the charge and discharge cycle. In the examples of the present application, the molar content of O in the list of positive electrode active materials is only a theoretical state value. The release of oxygen from the lattice will cause the molar content of oxygen to change, and the actual molar content of O will fluctuate.

[0201] In some embodiments, the positive electrode active material includes: LiNi 0.90 Co 0.06 Mn 0.04 O2、LiNi 0.7 Co 0.1 Mn 0.2 O2、LiNi 0.7 Co 0.2 Mn 0.1 O2 or LiNi 0.8 Co 0.1 Mn 0.1 At least one of O2.

[0202] In some embodiments, the negative electrode active material includes a composite material of silicon and graphite, or a mixture of silicon and graphite, wherein the graphite can be natural graphite or artificial graphite.

[0203] As an example, the negative electrode active material is a mixture of silicon-carbon material and artificial graphite, wherein, based on the total mass of the negative electrode active material, the mass content of artificial graphite is about 95%, the mass content of silicon-carbon material is about 5%, and the mass content of silicon in the silicon-carbon material is about 50%.

[0204] As an embodiment, the positive electrode active material is LiNi 0.90 Co 0.06 Mn 0.04 O2, the negative electrode active material is a mixture of silicon carbon material and graphite. Further, as another example, the positive electrode active material is LiNi 0.90 Co 0.06 Mn 0.04 O2, the negative electrode active material is a mixture of silicon-carbon material and graphite, and based on the total mass of the negative electrode active material, the mass content of artificial graphite is about 95%, the mass content of silicon-carbon material is about 5%, and the mass content of silicon in the silicon-carbon material is about 50%.

[0205] In the above embodiment, the arrangement of the positive electrode active material and the negative electrode active material can enable the battery cell 20 to have a higher energy density.

[0206] In some embodiments, the housing 21 is made of carbon steel or stainless steel.

[0207] Selecting carbon steel or stainless steel can reduce the risk of electrolyte corrosion of the housing 21. For example, in some embodiments, the housing 21 is electrically connected to the negative electrode tab and is in a low potential state. The steel housing 21 is not easily corroded by the electrolyte in this low potential state.

[0208] In some embodiments, the battery cell 20 is a cylindrical battery cell 20 , so that the shape of the current collecting member 24 matches the shape of the battery cell 20 , facilitating assembly of the battery cell 20 .

[0209] In some embodiments, the shell 21 includes a cylinder 210 and a cover 211 connected to the cylinder 210. The cover 211 and the cylinder 210 are formed as an integral or separate structure. The cylinder 210 is arranged around the outer periphery of the electrode assembly 22, and the cover 211 is provided with an electrode lead-out hole 2111; the battery cell 20 also includes an electrode terminal 25, and the electrode terminal 25 is insulated and arranged in the electrode lead-out hole 2111.

[0210] As an example, the cover body 211 and the cylinder body 210 are an integrally formed structure.

[0211] As another example, the cover 211 and the barrel 210 are separate molding structures. The cover 211 can be disc-shaped, and the barrel 210 can be cylindrical.

[0212] In this embodiment, one of the shell 21 and the electrode terminal 25 is the positive output pole of the battery cell 20, and the other is the negative output pole of the battery cell 20. At least a portion of the shell 21 itself can serve as an output pole of the battery cell 20, thereby eliminating an electrode terminal, which is beneficial to simplifying the structure of the battery cell 20.

[0213] An embodiment of the present application provides a battery, comprising the battery cell 20 in any of the above embodiments.

[0214] An embodiment of the present application provides an electrical device, comprising the battery in any of the above embodiments.

[0215] In one embodiment of the present application, a battery cell 20 includes an electrode assembly 22, a housing 21, an end cap 23, and a current collecting member 24. The housing 21 is used to accommodate the electrode assembly 22 and the current collecting member 24. The housing 21 has an opening, and the end cap 23 is used to cover the opening. The current collecting member 24 is connected to the electrode assembly 22 and the housing 21, respectively, so that the electrode assembly 22 and the housing 21 are electrically connected through the current collecting member 24. The negative electrode active material in the battery cell 20 includes silicon, and the battery cell 20 has a high energy density and high expansion. The current collecting member 24 includes a current collecting body 240 and an elastic portion 241. The current collecting body 240 is an annular structure. The elastic portion 241 is located on the inner side of the current collecting body 240 and is connected to the current collecting body 240. The elastic portion 241 protrudes from the current collecting body 240 toward the end cap 23 and abuts against the end cap 23. Through the above-mentioned arrangement, the battery cell 20 can have a higher energy density while reducing the impact of the high expansion rate of the active material on the battery cell 20. The risk of the electrode assembly 22 being squeezed, thereby causing powder loss and lithium deposition, is lower, and the battery cell 20 has higher reliability and higher energy density.

[0216] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted 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 encompasses all technical solutions within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: An electrode assembly (22) includes a negative electrode plate, wherein the negative electrode plate includes a negative electrode active material capable of reversibly extracting and inserting metal ions, and the negative electrode active material includes silicon; A shell (21) is provided with an opening, and the shell (21) is used to accommodate the electrode assembly (22); an end cover (23) covering the opening; a current collecting member (24), housed in the housing (21) and located on a side of the electrode assembly (22) facing the end cover (23), the current collecting member (24) being electrically connected to the tab (221) of the electrode assembly (22) and the housing (21); The current collecting component (24) includes a current collecting body (240) and an elastic portion (241), wherein the current collecting body (240) is an annular structure, and the elastic portion (241) is located on the inner side of the current collecting body (240) and connected to the current collecting body (240), and the elastic portion (241) protrudes from the current collecting body (240) at least partially along the thickness direction of the end cover (23) and abuts against the end cover (23).

2. The battery cell according to claim 1, wherein: The elastic portion (241) can be deformed during the charge and discharge process of the battery cell.

3. The battery cell according to claim 1 or 2, characterized in that: The end cover (23) is provided with a first protrusion (232), the first protrusion (232) protruding toward the electrode assembly (22) along the thickness direction of the end cover (23), and the first protrusion (232) abuts against the elastic part (241).

4. The battery cell according to any one of claims 1 to 3, characterized in that: The current collecting member (24) further includes a central portion (2413), and the central portion (2413) is located inside the elastic portion (241).

5. The battery cell according to claim 4, characterized in that The central portion (2413) abuts against the tab (221) of the electrode assembly (22).

6. The battery cell according to claim 4 or 5, characterized in that: The elastic portion (241) includes a first piece (2411) and a second piece (2412), wherein the first piece (2411) is connected to the inner side of the current collecting body (240) and extends obliquely toward the end cover (23), and the second piece (2412) is connected to the outer side of the central portion (2413) and extends obliquely toward the end cover (23). The first piece (2411) and the second piece (2412) are connected at an angle greater than 0° and less than 180° to form a contact area (2414), and the contact area (2414) contacts the end cover (23).

7. The battery cell according to claim 6, characterized in that The end cover (23) comprises an end cover body (231) and a first protrusion (232), wherein the first protrusion (232) protrudes toward the electrode assembly (22) along the thickness direction of the end cover (23), and the first protrusion (232) abuts against the abutment area (2414).

8. The battery cell according to claim 6 or 7, characterized in that: The elastic portion (241) is provided with a first through hole (2415) penetrating the elastic portion (241) along the thickness direction of the elastic portion (241), and the first through hole (2415) extends from the first piece (2411) to the second piece (2412).

9. The battery cell according to any one of claims 1 to 8, characterized in that: There are a plurality of elastic parts (241), and each elastic part (241) is arranged at intervals along the circumference of the current collecting body (240).

10. The battery cell according to claim 9, characterized in that: The current collecting component (24) further includes a current collecting sheet (242) connected to the current collecting body (240), one current collecting sheet (242) being provided between two adjacent elastic portions (241), a surface of the current collecting sheet (242) facing away from the end cover (23) being connected to the electrode tab (221) of the electrode assembly (22), and the current collecting sheet (242) and the elastic portion (241) being spaced apart.

11. The battery cell according to claim 10, characterized in that At least one current collecting piece (242) is welded to the electrode tab (221) of the electrode assembly (22) to form a plurality of welding portions (2421), and the plurality of welding portions (2421) are arranged at intervals along the circumference of the current collecting body (240).

12. The battery cell according to claim 11, characterized in that The welding portion (2421) includes a first welding portion (24211) and two second welding portions (24212), the first welding portion (24211) is located between the two second welding portions (24212), and the length of the first welding portion (24211) is greater than the length of the second welding portion (24212).

13. The battery cell according to any one of claims 1 to 12, characterized in that: The end cover (23) is provided with an end cover body (231) and a pressure relief mechanism (26). The pressure relief mechanism (26) is located inside the end cover body (231), and the elastic portion (241) abuts against the pressure relief mechanism (26).

14. The battery cell according to claim 13, characterized in that The pressure relief mechanism (26) is provided with a first protrusion (232), which protrudes toward the electrode assembly (22) along the thickness direction of the end cover (23), and abuts against the abutment area (2414) of the elastic part (241).

15. The battery cell according to claim 14, characterized in that The end cover (23) is provided with a notched groove (261), and the area defined by the notched groove (261) forms the pressure relief mechanism (26), and the first protrusion (232) is located inside the notched groove (261) and is spaced apart from the notched groove (261).

16. The battery cell according to any one of claims 1 to 15, characterized in that: A limiting portion (211) is convexly provided on the inner side surface of the shell (21), the current collecting component (24) abuts against the limiting portion (211), and the tab (221) of the electrode assembly (22) is electrically connected to the shell (21) through the current collecting component (24).

17. The battery cell according to claim 16, characterized in that The current collecting component (24) is welded to the housing (21).

18. The battery cell according to any one of claims 1 to 17, characterized in that: The negative electrode active material includes at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, silicon-containing alloys, or silicon-oxygen-carbon composite materials.

19. The battery cell according to claim 18, characterized in that Based on the total mass of the negative electrode active material, the mass content A of the silicon element in the negative electrode active material satisfies: 1 wt %≤A≤15 wt %.

20. The battery cell according to claim 19, characterized in that Based on the total mass of the negative electrode active material, the mass content A of the silicon element in the negative electrode active material satisfies: 2 wt %≤A≤8 wt %.

21. The battery cell according to any one of claims 1 to 20, characterized in that: The electrode assembly (22) further comprises a positive electrode sheet and a separator, wherein the separator is located between the positive electrode sheet and the negative electrode sheet; The positive electrode plate includes a positive electrode active material, the chemical formula of which satisfies: Li 1+a [Ni x Co y Mn z M b ]O2, M includes at least one of Zr, Al, Ti, Sb, Nb, Te, Mg, B, Ca, V, Ta or Sr, 0.1≥a≥-0.1, 1>x≥0.7, 0.3>y>0, 0.3>z>0, 0.3>b≥0, x+y+z+b=1.

22. The battery cell according to any one of claims 1 to 21, characterized in that: The material of the housing (21) includes carbon steel or stainless steel.

23. The battery cell according to any one of claims 1 to 22, characterized in that: The battery cell is a cylindrical battery cell.

24. The battery cell according to any one of claims 1 to 23, characterized in that: The housing (21) comprises a cylinder (210) and a cover (211) connected to the cylinder (210); the cover (211) and the cylinder (210) are integrally or separately formed; the cylinder (210) is arranged around the outer periphery of the electrode assembly (22); and the cover (211) is provided with an electrode lead-out hole (2111); The battery cell further includes an electrode terminal (25), and the electrode terminal (25) is insulated and arranged in the electrode lead-out hole (2111).

25. A battery, characterized in that: include: The battery cell according to any one of claims 1 to 24.

26. An electrical device, characterized in that: include: The battery according to claim 25.

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