Battery monomer, battery and electric device

Abstract

A battery cell (20), a battery (10) and an electric device belong to the technical field of batteries. The battery cell (20) comprises: an electrode assembly (22) comprising a negative pole piece, the negative pole piece comprising a negative active material capable of reversibly deintercalating-intercalating metal ions, the negative active material comprising a silicon element; the shell (21) is provided with an opening, and the shell (21) is used for accommodating the electrode assembly (22); the end cover (23) covers the opening; the current collecting component (24) is accommodated in the shell (21) and is positioned on one side, facing the end cover (23), of the electrode assembly (22), and the current collecting component (24) is electrically connected to a tab of the electrode assembly (22) and the shell (21); wherein the current collecting component (24) comprises a current collecting body (240) and an elastic part (241), the current collecting body (240) is of an annular structure, the elastic part (241) is located on the inner side of the current collecting body (240) and connected with the current collecting body (240), and at least part, in the thickness direction of the end cover (23), of the elastic part (241) protrudes out of the current collecting body (240) and abuts against the end cover (23). The product contributes to the consideration of the energy density and reliability of the battery cells (20).

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery monomer, a battery and a power utilization device. BACKGROUND

[0002] With the increasing environmental pollution, new energy industry is attracting more and more attention. In the new energy industry, battery technology is an important factor for its development.

[0003] The development of battery technology needs to consider many design factors, such as energy density, cycle life, reliability, etc. Silicon-containing materials as negative active materials are beneficial to the energy density of the battery monomer, however, the battery monomer containing silicon material has a high expansion rate, and the high expansion rate has a certain influence on the improvement of the reliability of the battery monomer. Therefore, how to provide a battery monomer to balance the energy density and reliability of the battery monomer is an urgent technical problem to be solved. SUMMARY

[0004] The present application provides a battery monomer, a battery and a power utilization device, which can balance the energy density and reliability of the battery monomer.

[0005] In a first aspect, a battery monomer is provided, comprising: an electrode assembly comprising a negative electrode tab, the negative electrode tab comprising a negative active material capable of reversible deintercalation-intercalation of metal ions, the negative active material comprising silicon element; a shell provided with an opening, the shell being used for accommodating 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 tab of the electrode assembly and the shell; wherein the current collecting member comprises a current collecting body and an elastic part, the current collecting body is an annular structure, the elastic part is located on the inner side of the current collecting body and connected with the current collecting body, the elastic part protrudes from the current collecting body in at least part of the thickness direction of the end cover and abuts against the end cover.

[0006] In the embodiment of the present application, the current collecting member is located on the side of the electrode assembly facing the end cover and is electrically connected with the tab of the electrode assembly and the shell, so that the current collecting member can realize the electrical connection between the electrode assembly and the shell. The negative active material in the battery monomer includes silicon, the battery monomer has a high energy density, and the electrode assembly in the battery monomer has a greater degree of expansion. The elastic part in the current collecting member has the ability of elastic deformation, and when the electrode assembly expands, the elastic part is compressed to provide space for the expansion of the electrode assembly, and the deformable elastic part can weaken the extrusion of the electrode assembly compared with the non-deformable rigid part, thereby reducing the risk of the electrode assembly being extruded, thereby facilitating the improvement of the reliability of the battery monomer. Therefore, the technical scheme of the embodiment of the present application can balance the energy density and the reliability of the battery monomer.

[0007] In a possible implementation, the elastic part is capable of deforming in the charging and discharging process of the battery monomer. In the charging and discharging process of the battery monomer, the electrode assembly expands, and since the elastic part is capable of deforming in the charging and discharging process of the battery monomer, the elastic part can be compressed to provide space for the expansion of the electrode assembly, thereby reducing the risk of the electrode assembly being extruded.

[0008] In a possible implementation, the end cover is provided with a first protruding part protruding toward the electrode assembly along the thickness direction of the end cover, and the first protruding part abuts against the elastic part.

[0009] In the above technical scheme, the provision of the first protruding part facilitates the improvement of the strength of the end cover, and the abutment of the first protruding part and the elastic part also facilitates the reduction of the size of the elastic part protruding from the current collecting body.

[0010] In a possible implementation, the current collecting member further includes a center part located on the inner side of the elastic part. In this way, the elastic part is located between the center part and the current collecting body, and the center part corresponds to the central region of the tab of the electrode assembly, thereby facilitating the provision of a certain supporting effect for the tab.

[0011] In a possible implementation, the center part abuts against the tab of the electrode assembly. In this way, the center part can provide a certain supporting effect for the tab, thereby facilitating the reduction of the shaking of the electrode assembly in the shell.

[0012] In a possible implementation, the elastic part includes a first sheet, a second sheet and a center part, the first sheet is connected to the inner side of the current collecting body and extends obliquely toward the end cover, the second sheet is connected to the outer side of the center part and extends obliquely toward the end cover, the first sheet and the second sheet are connected at an included angle greater than 0° and less than 180° and form an abutment area, and the abutment area abuts against the end cover.

[0013] In the technical solution, the center part abuts against the electrode assembly, the abutting area formed by the connection of the first sheet and the second sheet abuts against the end cover, and the elastic part has the ability of elastic deformation, so that during the expansion of the electrode assembly, the abutting area is compressed to provide space for the expansion of the electrode assembly, and the center part can provide soft support to the electrode assembly, so as to reduce the strength of the extrusion of the electrode assembly and the risk of excessive extrusion of the electrode assembly, such as powder dropping and lithium precipitation.

[0014] In a possible implementation, the end cover comprises an end cover body and a first protruding part, the first protruding part protrudes towards the electrode assembly along the thickness direction of the end cover, and the first protruding part abuts against the abutting area. The first protruding part is beneficial to improving the strength of the end cover and facilitating the abutment of the end cover and the abutting area of the elastic part.

[0015] In a possible implementation, the elastic part is provided with a first through hole penetrating through the elastic part along the thickness direction of the elastic part, and the first through hole extends from the first sheet to the second sheet.

[0016] The first through hole is beneficial to the deformation of the elastic part, thereby further reducing the risk of extrusion of the electrode assembly; in addition, the first through hole is also beneficial to the discharge of high-temperature and high-pressure substances inside the battery cell during thermal runaway.

[0017] In a possible implementation, the elastic part is a plurality of elastic parts, and each elastic part is arranged at intervals along the circumferential direction of the current collecting body. In this way, the elastic parts are more uniformly distributed in the current collecting member, and the deformation of the plurality of elastic parts is more uniform, thereby facilitating more uniform relief of the extrusion force on the electrode assembly and reducing the risk that different regions of the electrode assembly are subjected to different degrees of extrusion. In addition, the interval between adjacent elastic parts is also beneficial to forming a relatively smooth exhaust passage and facilitating the discharge of high-temperature and high-pressure substances inside the battery cell during thermal runaway.

[0018] In a possible implementation, the current collecting member further comprises a current collecting sheet connected to the current collecting body, one current collecting sheet is arranged between two adjacent elastic parts, the side surface of the current collecting sheet away from the end cover is connected to the tab of the electrode assembly, and the current collecting sheet and the elastic part are spaced apart.

[0019] In the technical solution, the side surface of the current collector away from the end cover is connected with the electrode assembly, so that the current of the electrode assembly can be transmitted to the shell through the current collector; the current collector is spaced from the elastic part, so that the spacing area between the current collector and the elastic part can form a smooth exhaust passage, which is beneficial to the smooth discharge of the exhaust in the battery monomer. In addition, the spacing area is provided between the current collector and the elastic part, and the current collector can move relative to the current collector body, which is beneficial to reducing the risk of the electrode assembly being extruded and torn.

[0020] In a possible implementation, the at least one current collector is welded with the tab of the electrode assembly and forms a plurality of welding portions, and the plurality of welding portions are arranged at intervals along the circumference of the current collector body. By providing a plurality of welding portions, the connection strength between the tab and the current collector can be enhanced.

[0021] In a possible implementation, the welding portion includes a first welding portion and two second welding portions, the first welding portion is located between the two second welding portions, and the length of the first welding portion is greater than the length of the second welding portion. In this way, the first welding portion and the second welding portion are arranged to adapt to the shape of the current collector, facilitating the welding between the welding portion and the current collector.

[0022] 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 part abuts against the pressure relief mechanism.

[0023] In the 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 being damaged due to interference with components other than the battery monomer, and is beneficial to improving the long-term reliability of the pressure relief mechanism; the elastic part abuts against the pressure relief mechanism, which facilitates the connection between the elastic part and the end cover.

[0024] In a possible implementation, a first protruding portion is arranged on the pressure relief mechanism, the first protruding portion protrudes towards the electrode assembly along the thickness direction of the end cover, and the first protruding portion abuts against the abutting area of the elastic part. In this way, the connection between the elastic part and the end cover is achieved.

[0025] In a possible implementation, the end cover is provided with a score groove, the area defined by the score groove forms the pressure relief mechanism, and the first protruding portion is located on the inner side of the score groove and is arranged at intervals with the score groove. In this way, the preparation of the score groove is facilitated, and the adverse effects of the precision of the score groove can be reduced; in addition, it is also beneficial to reduce the risk of interference between the pressure relief mechanism and structures other than the battery monomer.

[0026] In a possible implementation, an inner side of the shell is provided with a limiting portion, the current collecting member abuts against the limiting portion, and the tab of the electrode assembly is electrically connected to the shell through the current collecting member. In this way, the end cover is limited, and the current collecting member is also limited, so that the current collecting member can limit the movement of the electrode assembly, reduce the displacement of the electrode assembly in the thickness direction of the end cover in the shell, and reduce the risk that the tab of the electrode assembly is disconnected from the current collecting member due to excessive displacement.

[0027] In a possible implementation, the current collecting member is welded to the shell. In this way, the electrical connection between the current collecting member and the shell is achieved through welding.

[0028] In a possible implementation, the negative active material includes at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, a silicon-containing alloy, or a silicon-oxygen-carbon composite material. The negative active material has a high gram capacity, and the use of the negative active material is beneficial to improving the energy density of the battery cell.

[0029] In a possible implementation, based on the total mass of the negative active material, the mass content A of silicon in the negative active material satisfies 1wt%≤A≤15wt%. Optionally, 2wt%≤A≤8wt%. In this way, the negative active material has a suitable mass content of silicon, so that the electrode assembly has a relatively suitable expansion rate, and the normal use of the battery cell is facilitated.

[0030] In a possible implementation, the electrode assembly further includes a positive electrode sheet and a separator, the separator is located between the positive electrode sheet and the negative electrode sheet, and the positive electrode sheet includes a positive active material, a chemical formula of the positive 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, and x+y+z+b=1.

[0031] The positive active material satisfying the above chemical formula has a high gram capacity, so that the battery cell prepared by using the positive active material has a high energy density.

[0032] In a possible implementation, the material of the shell includes carbon steel or stainless steel. The steel shell is not easily corroded by the electrolyte, and is beneficial to improving the reliability of the battery cell.

[0033] In a possible implementation, the battery cell is a cylindrical battery cell. In this way, the shape of the battery cell and the shape of the current collecting member are matched, facilitating assembly of the battery cell.

[0034] In a possible implementation, the shell comprises a barrel and a cover connected to the barrel, the cover and the barrel are integrally formed or separately formed, the barrel is arranged around the outer periphery of the electrode assembly, and the cover is provided with an electrode lead-out hole; the battery cell further comprises an electrode terminal, and the electrode terminal is insulated and arranged in the electrode lead-out hole. In this way, one of the shell and the electrode terminal is the positive output pole of the battery cell, and the other is the negative output pole of the battery cell. At least part of the shell itself can serve as one output pole of the battery cell, so that one electrode terminal can be omitted, and the structure of the battery cell is facilitated to be simplified.

[0035] In a second aspect, a battery is provided, comprising the battery cell as in the first aspect and any possible implementation thereof.

[0036] In a third aspect, a power consumption device is provided, comprising the battery as in the second aspect.

[0037] In the embodiments of the present application, the current collecting member is located at the side of the electrode assembly facing the end cover and is electrically connected with the tab of the electrode assembly and the shell. In this way, the current collecting member can realize the electrical connection between the electrode assembly and the shell. The negative active material in the battery cell comprises silicon elements, the battery cell has a high energy density, and the electrode assembly in the battery cell has a greater degree of expansion. The elastic part in the current collecting member has the ability of elastic deformation. When the electrode assembly expands, the elastic part is compressed to provide space for the expansion of the electrode assembly. The deformable elastic part can weaken the extrusion effect on the electrode assembly compared with the non-deformable rigid part, so as to reduce the risk of the electrode assembly being extruded, thereby facilitating to improve the reliability of the battery cell. Therefore, the technical scheme of the embodiments of the present application can balance the energy density and the reliability of the battery cell. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by the drawings without paying creative labor.

[0039] Figure 1 A structural schematic diagram of a vehicle according to an embodiment of the present application;

[0040] Figure 2A structural diagram of a battery according to an embodiment of the present application;

[0041] Figure 3 An exploded structural diagram of a battery cell according to an embodiment of the present application;

[0042] Figure 4 A structural diagram of a battery cell according to an embodiment of the present application;

[0043] Figure 5 A structural diagram of a battery according to an embodiment of the present application; Figure 4 A cross-sectional view of the battery cell along the A-A direction in FIG. 1;

[0044] Figure 6 A structural diagram of a battery according to an embodiment of the present application; Figure 5 An enlarged diagram of the region B in FIG. 1;

[0045] Figure 7 A structural diagram of an electrode assembly according to an embodiment of the present application;

[0046] Figure 8 A structural diagram of a current collecting member according to an embodiment of the present application;

[0047] Figure 9 A structural diagram of a current collecting member according to an embodiment of the present application;

[0048] Figure 10 A structural diagram of a current collecting member according to an embodiment of the present application;

[0049] Figure 11 A structural diagram of an end cap according to an embodiment of the present application;

[0050] Figure 12 An exploded structural diagram of a battery cell according to another embodiment of the present application;

[0051] Figure 13 A structural diagram of a battery cell according to an embodiment of the present application;

[0052] Figure 14 A structural diagram of a battery according to an embodiment of the present application; Figure 13 A cross-sectional view of the battery cell along the A'-A' direction in FIG. 7;

[0053] Figure 15 A structural diagram of a battery according to an embodiment of the present application; Figure 14 An enlarged diagram of the region C in FIG. 7.

[0054] In the drawings, the drawings are not drawn according to the actual proportions.

[0055] Reference signs: 1: vehicle; 10: battery; 30: controller; 40: motor; 3: box; 31: first box; 32: second box; 20: battery cell; 21: shell; 210: cylinder; 211: cover; 2111: electrode lead-out hole; 212: limiting portion; 22: electrode assembly; 23: end cover; 24: current collecting member; 25: electrode terminal; 26: pressure relief mechanism; 261: score groove; 240: current collecting body; 241: elastic portion; 242: current collecting sheet; 2411: first sheet; 2412: second sheet; 2413: center portion; 2414: abutting region; 2415: first through hole; 2401: first gap; 2402: second gap; 231: end cover body; 232: first protruding portion. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be described below with reference to the drawings.

[0057] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0058] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the present application are only for the purpose of describing the specific embodiments of the present application, and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover not exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, and are not intended to describe a particular order or primary and secondary relationship.

[0059] In the present application, the phrase "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The phrase appears at various places in the specification does not necessarily refer to the same embodiment, nor is it mutually exclusive or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.

[0060] In the description of the present application, it should be noted that unless specifically stated and limited otherwise, the terms "mounting", "connected", "connection", "attach" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected, can be directly connected, or indirectly connected through an intermediate medium, and can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0061] The term "and / or" in the present application only describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally represents that the front and rear associated objects have an "or" relationship.

[0062] In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, the detailed description of the same components is omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, and the overall thickness, length, width and other dimensions of the integrated device are only exemplary and should not constitute any limitation on the present application.

[0063] "Multiple" appearing in the present application means more than two (including two), and similarly, "multiple groups" means more than two groups (including two groups), and "multiple pieces" means more than two pieces (including two pieces).

[0064] In the embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging.

[0065] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead-acid battery, etc. The embodiments of the present application are not limited in this regard.

[0066] In some implementations, the battery cell in the embodiments of the present application can be a metal battery, specifically, the metal battery can include a lithium metal secondary battery, a sodium metal battery, or a magnesium metal battery, etc. The embodiments of the present application are not limited in this regard.

[0067] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. During the charging and discharging process of the battery cell, active ions (such as lithium ions) are inserted and extracted between the positive electrode sheet and the negative electrode sheet. The separator is arranged between the positive electrode sheet and the negative electrode sheet, which can prevent the positive and negative electrodes from short-circuiting, and at the same time, the active ions can pass through.

[0068] In some embodiments, the positive electrode tab can include a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, the positive electrode film layer including a positive electrode active material. Optionally, the positive electrode film layer further includes a conductive agent and a binder.

[0069] As an example, the positive electrode current collector has two surfaces opposite in the thickness direction thereof, and the positive electrode film layer is disposed on either one or both of the two surfaces of the positive electrode current collector.

[0070] As an example, the positive electrode current collector can employ a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. can be employed. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, or a foam carbon, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0071] As an example, the positive electrode active material can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material can also be used. These positive electrode active materials can be used alone only one or two or more can be used in combination. Among them, examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFeP04 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnP04), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.

[0072] In some embodiments, the negative electrode tab can include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, the negative electrode film layer including a negative electrode active material. Optionally, the negative electrode film layer includes a conductive agent and a binder.

[0073] As an example, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode film layer is disposed on either one or both of the two surfaces of the negative electrode current collector.

[0074] As an example, the negative current collector can employ a metal foil, a foam metal, or a composite current collector. For example, as a metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, or the like can be employed. The composite current collector can include a polymer material base layer and a metal layer. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, or a foam carbon, or the like. The composite current collector can be formed by forming a metal material (copper, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, or the like) on a polymer material base material (such as a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0075] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode tab and the negative electrode tab.

[0076] In some embodiments, the separator is a separator film. The type of the separator film is not particularly limited in the present application, and any publicly known porous structure separator film having good chemical stability and mechanical stability can be used.

[0077] As an example, the main material of the separator film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride, and ceramic.

[0078] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive electrode tab and the negative electrode tab, and functions to transport ions and separate the positive electrode and the negative electrode.

[0079] In some embodiments, the battery cell further includes an electrolyte, which functions to conduct ions between the positive electrode and the negative electrode. The type of the electrolyte is not particularly limited in the present application, and can be selected as needed. The electrolyte can be in a liquid state, a gel state, or a solid state.

[0080] In some embodiments, the electrode assembly is provided with a tab, which can lead current out of the electrode assembly. The tab includes a positive tab and a negative tab.

[0081] In some embodiments, the battery cell can include a case. The case is used to package the electrode assembly and the electrolyte, and the like. The case can be a steel case, an aluminum case, a plastic case (such as a polypropylene case), a composite metal case (such as a copper-aluminum composite case), or an aluminum-plastic film, or the like.

[0082] The battery mentioned in the embodiments of the present application can include one or more battery cells to provide a single physical module with higher voltage and capacity. When there are a plurality of battery cells, the plurality of battery cells are connected in series, in parallel, or in a mixed connection through a bus member.

[0083] In some embodiments, the battery can be a battery pack, which can include a case and battery cells, the battery cells or battery modules being housed in the case.

[0084] In some embodiments, the case can be part of a chassis structure of a vehicle. For example, part of the case can be at least part of a floor of the vehicle, or part of the case can be at least part of a cross beam and a longitudinal beam of the vehicle.

[0085] In some embodiments, the battery can be located in an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0086] The development of battery technology needs to consider various design factors, such as energy density, cycle life, discharge capacity, charge-discharge rate, reliability, etc. In some settings, a material containing silicon is selected as a negative active material to prepare a battery cell to improve the energy density of the battery cell. However, although such a battery cell has a higher energy density, the expansion problem of the battery cell during use is more prominent due to the higher expansion rate of the silicon-containing material. Therefore, how to provide a battery cell to reduce the adverse effects of high expansion rate on the battery cell, while taking into account the energy density and reliability of the battery cell, is a technical problem to be solved.

[0087] Therefore, the embodiments of the present application provide a battery cell, which includes a silicon-containing negative active material, and a current collecting member in the battery cell includes an elastic portion protruding from a current collecting body, the elastic portion abutting against an end cover of the battery cell. Since the elastic portion has the ability of elastic deformation, during the expansion of the electrode assembly, the elastic portion can be compressed to provide a buffer space for the expansion of the electrode assembly, reducing the risk of the electrode assembly being squeezed, thereby facilitating the consideration of the energy density and reliability of the battery cell.

[0088] The technical solutions described in the embodiments of the present application are applicable to various battery-using electrical equipment.

[0089] The electrical equipment can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, and an electric tool, etc. The vehicle can be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile, etc. The spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy, and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, etc. The embodiments of the present application do not specially limit the above electrical equipment.

[0090] For ease of explanation, the following embodiments use a vehicle as an example of electrical equipment.

[0091] For example, such as Figure 1 The diagram shown is a structural schematic of a vehicle according to one embodiment of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A motor 40, a controller 30, and a battery 10 can be installed inside vehicle 1. The controller 30 controls the battery 10 to supply power to the motor 40. For example, the battery 10 can be installed at the bottom, front, or rear of vehicle 1. The battery 10 can be used to power vehicle 1; for example, it can serve as the operating power source for vehicle 1's electrical system, such as meeting the power requirements for starting, navigation, and operation. In another embodiment of this application, the battery 10 can not only serve as the operating power source for vehicle 1 but also as the driving power source, replacing or partially replacing gasoline or natural gas to provide driving power to vehicle 1.

[0092] To meet diverse power demands, battery 10 may include multiple individual battery cells 20. The number of individual battery cells 20 can be set arbitrarily according to different power requirements. Multiple individual battery cells 20 can be connected in series, parallel, or a combination thereof to achieve greater capacity or power. Since each battery 10 may contain a large number of individual battery cells 20, for ease of installation, the individual battery cells 20 can be grouped, with each group forming a battery module. The number of individual battery cells 20 included in a battery module is unlimited and can be set according to requirements. A battery may include multiple battery modules, which can be connected in series, parallel, or a combination thereof.

[0093] For example, such as Figure 2 The diagram shown is a structural schematic of a battery according to an embodiment of this application. The battery 10 may include multiple battery cells 20. The battery 10 may also include a housing 3, which has a hollow interior, housing the multiple battery cells 20. For example, the multiple battery cells 20 may be connected in parallel, series, or a combination thereof and then placed inside the housing 3. The housing 3 may include a first housing 31 and a second housing 32, which are closed to each other to form the housing 3. The first housing 31 and the second housing 32 may both be hollow structures with an opening at one end; alternatively, the first housing 31 may be a plate-like structure, and the second housing 32 may be a hollow structure with an opening at one end.

[0094] Optionally, the battery 10 can further include other structures, which are not described herein. For example, the battery 10 can further include a current collecting component for realizing electrical connection between the plurality of battery cells 20, such as parallel connection, series connection or mixed connection. Specifically, the current collecting component can realize the electrical connection between the battery cells 20 by connecting the electrode terminals of the battery cells 20. Further, the current collecting component can be fixed to the electrode terminals of the battery cells 20 by welding. The electrical energy of the plurality of battery cells 20 can be further led out through the box 3 by a conductive mechanism. Optionally, the conductive mechanism can also belong to the current collecting component.

[0095] Figure 3 An exploded schematic view of a structure of a battery cell according to an embodiment of the present application, Figure 4 A schematic view of a battery cell according to an embodiment of the present application, Figure 5 A cross-sectional view of the battery cell in Figure 4 along the A-A direction, Figure 6 A schematic view of the region B in Figure 5 .

[0096] In an embodiment of the present application, for example, as shown in Figures 3 to 6 , the battery cell 20 includes a housing 21, an electrode assembly 22, an end cover 23 and a current collecting member 24.

[0097] The housing 21 is provided with an opening for accommodating the electrode assembly 22 and the current collecting member 24.

[0098] The housing 21 can be a hollow structure with an opening at one end or a hollow structure with openings at both ends. As an example, in combination with Figure 3 , the housing 21 is a hollow structure with an opening at one end, and the end cover 23 is used to cover the opening of the housing 21.

[0099] The material of the housing 21 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The housing 21 can have various shapes, such as a cylinder, a cuboid, etc. As an example, in an embodiment of the present application, the material of the housing 21 is steel, and the housing 21 is a cylinder.

[0100] The electrode assembly 22 is a component in which an electrochemical reaction occurs in the battery cell 20. The electrode assembly 22 includes a positive electrode tab, a negative electrode tab, and a separator between the positive electrode tab and the negative electrode tab. The positive electrode tab includes a positive electrode current collector and a positive electrode film layer coated on a surface of the positive electrode current collector, and the current collector on which the positive electrode film layer is not coated protrudes from the current collector on which the positive electrode film layer is coated, and the current collector on which the positive electrode film layer is not coated serves as a positive electrode tab. The negative electrode tab includes a negative electrode current collector and a negative electrode film layer coated on a surface of the negative electrode current collector, and the current collector on which the negative electrode film layer is not coated protrudes from the current collector on which the negative electrode film layer is coated, and the current collector on which the negative electrode film layer is not coated serves as a negative electrode tab. The positive electrode tab, the separator, and the negative electrode tab can be formed into the electrode assembly 22 by winding or stacking.

[0101] As an example, the positive electrode tab, the separator, and the negative electrode tab are wound into the electrode assembly 22, and a region in which the positive electrode film layer and / or the negative electrode film layer is provided in the electrode assembly 22 after winding can be referred to as a main body portion of the electrode assembly 22, and a region in which the positive electrode film layer and the negative electrode film layer are not provided is referred to as a tab of the electrode assembly 22. Figure 7 A schematic view of an electrode assembly according to an embodiment of the present application is shown. For example, as shown in FIG. 1, the electrode assembly 22 includes a tab 221 and a main body portion 222, and the tab 221 is closer to the current collecting member 24 than the main body portion 222 in the axial direction of the cylindrical electrode assembly 22 (for example, the z direction in FIG. 1). Figure 7 Figure 7

[0102] The negative electrode tab includes a negative electrode current collector and a negative electrode film layer provided on at least one side surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material capable of reversibly deintercalating and intercalating metal ions, and the negative electrode active material includes a silicon element.

[0103] The metal ions can be reversibly deintercalated from the negative electrode active material or reversibly intercalated into the negative electrode active material. As an example, in a lithium ion battery cell, lithium ions can be reversibly intercalated into or deintercalated from the negative electrode active material. As another example, in a sodium ion battery cell, sodium ions can be reversibly intercalated into or deintercalated from the negative electrode active material.

[0104] The negative electrode active material includes a silicon element. For example, the negative electrode active material can be a silicon-based material.

[0105] Optionally, the negative electrode active material further includes a carbon element. For example, the negative electrode active material is a silicon-carbon composite material.

[0106] In addition to the negative electrode active material, the negative electrode film layer can further include a conductive agent and a binder. As an example, in the process of preparing the negative electrode tab, the negative electrode active material, the conductive agent, and the binder are mixed to prepare a slurry, and the slurry is coated on the negative electrode current collector to prepare the negative electrode film layer. ​​

[0107] The end cover 23 is used to cover the opening of the shell 21 to isolate the internal environment of the battery cell 20 from the external environment. The end cover 23 covers the opening of the shell 21, and the end cover 23 and the shell 21 together define a sealed space for accommodating the electrode assembly 22, the electrolyte, and the current collecting member 24.

[0108] The shape of the end cover 23 can be adapted to the shape of the shell 21, for example, the shell 21 is a cuboid structure, and the end cover 23 is a rectangular plate structure adapted to the shell 21, or for example, the shell 21 is a cylindrical structure, and the end cover 23 is a circular plate structure adapted to the shell 21. The material of the end cover 23 can also be various, for example, the end cover 23 can be a metal material, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cover 23 can be the same as or different from the material of the shell 21. As an example, the material of the end cover 23 is copper.

[0109] In the battery cell 20, the end cover 23 can be one or two. If the shell 21 is a hollow structure with an opening at one end, one end cover 23 is correspondingly provided; if the shell 21 is a hollow structure with openings at both ends, two end covers 23 are correspondingly provided, and the two end covers 23 cover the two openings of the shell 21, respectively, one of the positive and negative tabs of the electrode assembly 22 is electrically connected to one end cover 23, and the other is electrically connected to the shell 21. In the embodiment in which the shell 21 is a hollow structure with an opening at one end, the end of the shell 21 away from the end cover 23 can be provided with an electrode terminal 25, and the electrode terminal 25 is insulatedly connected to the shell 21, one of the positive and negative tabs of the electrode assembly 22 is electrically connected to the shell 21, and the other is electrically connected to the electrode terminal 25.

[0110] The current collecting member 24 is accommodated in the shell 21 and located at the side of the electrode assembly 22 facing the end cover 23, and the current collecting member 24 is electrically connected to the electrode assembly 22 and the shell 21. In this way, the shell 21 can serve as one output pole of the battery cell 20. Specifically, the current collecting member 24 is electrically connected to the tabs 221 of the electrode assembly 22 and the shell 21.

[0111] The current collecting member 24 can be a disc-shaped member arranged between the end cover 23 and the electrode assembly 22, for example, the shell 21 is a cylinder, 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.

[0112] Figure 8 A structural schematic view of the current collecting member of an embodiment of the present application, Figure 9 A structural schematic view of the current collecting member of an embodiment of the present application, Figure 10 A structural schematic view of the current collecting member of an embodiment of the present application. Figures 8 to 10Structural schematic diagrams of the current collecting members for different viewing angles, respectively.

[0113] In combination Figures 7 to 10 As shown, the current collecting member 24 includes a current collecting body 240 and an elastic portion 241, the current collecting body 240 is in a ring structure, the elastic portion 241 is located on the inner side of the current collecting body 240 and connected with the current collecting body 240, the elastic portion 241 protrudes from the current collecting body 240 in at least part of the thickness direction of the end cover 23 and abuts against the end cover 23.

[0114] In the thickness direction of the end cover 23, the elastic portion 241 protrudes from the current collecting body 240 in a direction away from the electrode assembly 22 and abuts against the end cover 23 relative to the current collecting body 240.

[0115] In the thickness direction of the end cover 23, the elastic portion 241 can partially protrude from the current collecting body 240 and abut against the end cover 23, or can fully protrude from the current collecting body 240 and abut against the end cover 23. By setting the elastic portion 241 to protrude from the current collecting body 240 in at least part of the thickness direction of the end cover 23, the abutment of the elastic portion 241 and the end cover 23 is facilitated.

[0116] In the case that the negative electrode active material in the negative electrode sheet includes silicon element, the negative electrode active material can accommodate more metal ions, which can effectively increase the energy density of the battery monomer; in addition, it also increases the deformation amount of the electrode assembly 22 in the battery monomer during use, especially during the charging process of the battery monomer, the metal ions are embedded into the negative electrode active material of the negative electrode sheet, which causes the volume expansion of the electrode assembly 22, and further increases the pressure of the electrode assembly 22 on the end cover 23 of the battery monomer. By setting the elastic portion 241, the deformable elastic portion 241 can weaken the extrusion effect on the electrode assembly 22 compared with the non-deformable rigid part; and the elastic portion 241 can be compressed to provide space for the expansion of the electrode assembly 22.

[0117] During the assembly process of the battery monomer 20, a pressing force can be set between the current collecting member 24 and the end cover 23, and the elastic portion 241 of the current collecting member 24 abuts against the end cover 23 after the assembly of the battery monomer 20 is completed. The elastic portion 241 has the ability of elastic deformation, in the case that the electrode assembly 22 expands, the elastic portion 241 can be compressed, so that the elastic portion 241 can provide a buffer space for the expansion of the electrode assembly 22, and reduce the risk of the electrode assembly 22 being extruded; and the deformable elastic portion 241 can weaken the extrusion effect on the electrode assembly 22 compared with the non-deformable rigid part, so as to further reduce the risk of the electrode assembly 22 being extruded, reduce the risk of the electrode assembly 22 being extruded, such as powder falling and lithium precipitation, and improve the reliability of the battery monomer.

[0118] In addition, since the elastic part 241 is in abutting contact with the end cover 23 when the battery monomer is assembled, even if the electrode assembly 22 shrinks during the subsequent charging and discharging process of the battery monomer 20, the elastic part 241 can still abut against the end cover 23.

[0119] In the embodiment of the present application, the current collecting member 24 is located on the side of the electrode assembly 22 facing the end cover 23 and is connected with the electrode assembly 22 and the shell 21, so that the current collecting member 24 can realize the electrical connection between the electrode assembly 22 and the shell 21. The negative active material includes silicon elements, the battery monomer 20 has a high energy density, and the electrode assembly 22 in the battery monomer 20 has a greater degree of expansion. The elastic part 241 in the current collecting member 24 has the ability of elastic deformation, and when the electrode assembly 22 expands, the elastic part 241 is compressed to provide space for the expansion of the electrode assembly 22, thereby reducing the risk of the electrode assembly 22 being extruded; and the deformable elastic part 241 can weaken the extrusion of the electrode assembly 22 compared with the non-deformable rigid part, thereby further reducing the risk of the electrode assembly 22 being extruded, reducing the risk of powder falling and lithium precipitation caused by the extrusion of the electrode assembly 22, and improving the reliability of the battery monomer. Therefore, the technical scheme of the embodiment of the present application is beneficial to improve the reliability of the battery monomer 20.

[0120] In some embodiments, the elastic part 241 can be deformed during the charging and discharging process of the battery monomer.

[0121] During the charging and discharging process of the battery monomer, the electrode assembly 22 expands and shrinks. In the case of expansion of the electrode assembly 22, the elastic part 241 can be compressed to provide space for the expansion of the electrode assembly 22; in the case of shrinkage of the electrode assembly 22, the elastic part 241 can return from the compressed state to the uncompressed state (or from a greater compression degree to a smaller compression degree).

[0122] In this embodiment, the elastic part 241 can be deformed during the charging and discharging process of the battery monomer, thereby providing space for the expansion of the electrode assembly 22; and in the case of shrinkage of the electrode assembly 22, it is also beneficial to the elastic part 241 to return to the original state.

[0123] In some embodiments, the end cover 23 is provided with a first protruding part 232 protruding along the thickness direction of the end cover 23 towards the electrode assembly 22, and the first protruding part 232 abuts against the elastic part 241.

[0124] In the above technical scheme, the provision of the first protruding part 232 is beneficial to improve the strength of the end cover 23, and the abutment of the first protruding part 232 and the elastic part 241 is also beneficial to reduce the size of the elastic part 241 protruding from the current collecting body 240.

[0125] In some embodiments, the current collecting member 24 further comprises a center portion 2413 located inside the elastic portion 241.

[0126] Since the current collecting body 240 is in a ring structure, the elastic portion 241 is located inside the current collecting body 240 and connected with the current collecting body 240, and the center portion 2413 is located inside the elastic portion 241, so that the center portion 2413 is substantially the central region of the current collecting member 24. Since the current collecting member 24 is electrically connected with the tab 221, the center portion 2413 substantially corresponds to the central region of the tab 221 of the electrode assembly 22.

[0127] As an example, the center portion 2413 is connected with the elastic portion 241, so that the center portion 2413, the elastic portion 241 and the current collecting body 240 can be connected to form an integral whole.

[0128] As an example, in the case of expansion of the electrode assembly 22, the center portion 2413 abuts against the tab 221.

[0129] As another example, in the case of contraction of the electrode assembly 22, there is a gap between the center portion 2413 and the tab 221.

[0130] As an example, in the process of charging and discharging of the battery cell, the center portion 2413 always abuts against the tab 221.

[0131] In this embodiment, the elastic portion 241 is located between the center portion 2413 and the current collecting body 240, and the center portion 2413 corresponds to the central region of the tab 221 of the electrode assembly 22, thereby facilitating to provide certain support to the tab 221.

[0132] The center portion 2413 can have a disc structure or an irregular sheet structure.

[0133] As an example, the center portion 2413 is provided with a through hole penetrating through the center portion 2413, so that the center portion 2413 is more fragile and is more likely to break when the battery cell 20 is in thermal runaway.

[0134] In some embodiments, the center portion 2413 abuts against the tab 221 of the electrode assembly 22. In this way, the center portion 2413 can provide certain support to the tab 221, which is conducive to reducing the swing of the electrode assembly 22 in the case of the battery cell 20.

[0135] In addition, in the case that the center portion 2413 is connected with the elastic portion 241, the deformation of the elastic portion 241 can drive the center portion 2413 to move, so that the risk of excessive extrusion of the center portion 2413 to the tab 221 when the electrode assembly 22 expands can be reduced.

[0136] In some embodiments, the elastic part 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 towards the end cover 23, the second piece 2412 is connected to the outer side of the center part 2413 and extends obliquely towards the end cover 23, the first piece 2411 and the second piece 2412 are connected at an included angle greater than 0° and less than 180° and form an abutting area 2414, the abutting area 2414 abuts against the end cover 23.

[0137] The included 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.

[0138] As an example, the first piece 2411 and the second piece 2412 are both in a strip structure. As another example, the first piece 2411 is in a strip structure and the second piece 2412 is in a ring structure.

[0139] As an example, along the thickness direction of the end cover 23, the current collecting body 240 and the center part 2413 are flush. That is, the current collecting body 240 and the center part 2413 are on the same plane.

[0140] The first piece 2411 and the second piece 2412 both protrude towards the end cover 23 relative to the center part 2413, the connection of the first piece 2411 and the second piece 2412 forms the abutting area 2414, the abutting area 2414 abuts against the end cover 23. In the case of expansion of the electrode assembly 22, the electrode assembly 22 expands towards the end cover 23, and then the electrode assembly 22 presses the center part 2413, the center part 2413 moves towards the end cover 23, and then drives the first piece 2411 and the second piece 2412 to move towards the end cover 23, the elastic part 241 deforms elastically and provides space for the expansion of the electrode assembly 22.

[0141] In the above technical solution, the center part 2413 abuts against the electrode assembly 22, the abutting area 2414 formed by the connection of the first piece 2411 and the second piece 2412 abuts against the end cover 23, and the elastic part 241 has the ability of elastic deformation, so that in the process of expansion of the electrode assembly 22, the abutting area 2414 is compressed to provide space for the expansion of the electrode assembly 22, and the center part 2413 can play a soft supporting role on the electrode assembly 22, which can reduce the strength of the extrusion on the electrode assembly 22, thereby reducing the risk of excessive extrusion of the electrode assembly 22, such as powder dropping and lithium precipitation.

[0142] In some embodiments, the end cover 23 comprises an end cover body 231 and a first protrusion 232 protruding towards the electrode assembly 22 along a thickness direction of the end cover 23, and the first protrusion 232 abuts against the abutting region 2414.

[0143] The end cover body 231 can be a plate structure, and as an example, the end cover body 231 is a circular plate structure.

[0144] The first protrusion 232 can 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 towards the electrode assembly 22.

[0145] The provision of the first protrusion 232 is conducive to improving the strength of the end cover 23, and is also conducive to reducing the distance between the end cover 23 and the abutting region 2414 along the thickness direction of the end cover 23, thereby facilitating the abutment of the end cover 23 against the abutting region 2414 of the elastic portion 241.

[0146] In some embodiments, the elastic portion 241 is provided with a first through hole 2415 penetrating through the elastic portion 241 along a thickness direction of the elastic portion 241, and the first through hole 2415 extends from the first sheet 2411 to the second sheet 2412.

[0147] As an example, the first through hole 2415 can be in the shape of a long strip. Alternatively, the first through hole 2415 can also be in the shape of a circle, a triangle, and an irregular shape.

[0148] Alternatively, independent first through holes 2415 can also be provided on the first sheet 2411 and the second sheet 2412 respectively, and the embodiments of the present application include but are not limited to this.

[0149] The provision of the first through hole 2415 is more conducive to the deformation of the elastic portion 241, thereby being conducive to further reducing the risk of the electrode assembly 22 being extruded. In addition, the provision of the first through hole 2415 is also conducive to the discharge of internal high-temperature and high-pressure substances when the battery monomer 20 is in thermal runaway.

[0150] In some embodiments, the elastic portion 241 is a plurality of elastic portions, and each elastic portion 241 is arranged along a circumferential direction of the current collecting body 240.

[0151] As an example, the first sheet 2411 and the second sheet 2412 are both in the shape of a strip, the current collecting member 24 comprises a plurality of first sheets 2411 and a plurality of second sheets 2412, and the plurality of first sheets 2411 and the plurality of second sheets 2412 are arranged along the circumferential direction of the current collecting body 240. As an example, the current collecting member 24 comprises three first sheets 2411 and three second sheets 2412.

[0152] As another example, the first piece 2411 is in a strip shape, and the second piece 2412 is in a circular ring shape. The current collecting member 24 includes a plurality of first pieces 2411 and one second piece 2412. The plurality of first pieces 2411 are arranged along the circumference of the second piece 2412 and connected to the second piece 2412. The plurality of first pieces 2411 are also arranged along the circumference of the current collecting body 240. As an example, the current collecting member 24 includes three first pieces 2411 and one second piece 2412.

[0153] As an example, the elastic part 241 is three, and the included angle between the two adjacent elastic parts 241 is 120°.

[0154] The elastic part 241 is multiple, and the distribution of the elastic part 241 in the current collecting member 24 is more uniform, and the deformation of the multiple elastic parts 241 is more uniform, thereby facilitating more uniform relief of the compression force received by the electrode assembly 22 and reducing the risk that different regions of the electrode assembly 22 receive different degrees of compression. In addition, the spacing between adjacent elastic parts 241 also facilitates the formation of a relatively smooth exhaust passage, which is conducive to the discharge of high-temperature and high-pressure substances inside the battery cell 20 during thermal runaway.

[0155] In some embodiments, the current collecting member 24 further includes a current collecting piece 242 connected to the current collecting body 240. One current collecting piece 242 is arranged 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 tab of the electrode assembly 22, and the current collecting piece 242 and the elastic part 241 are spaced apart.

[0156] As an example, one current collecting piece 242 is arranged between two adjacent first pieces 2411. The current collecting piece 242 is spaced apart from the first piece 2411 and spaced apart from the second piece 2412. For example, a second gap 2402 is arranged between the current collecting piece 242 and the second piece 2412 of the elastic part 241, and a first gap 2401 is arranged between the current collecting piece 242 and the first piece 2411 of the elastic part 241. The second gap 2402 can be a through hole penetrating the current collecting member 24, and the first gap 2401 can be a through hole penetrating the current collecting member 24.

[0157] The current collecting piece 242 has two surfaces opposite in the thickness direction thereof. The side surface of the current collecting piece 242 facing the electrode assembly 22 (which can also be referred to as the side surface facing away from the end cover 23) is connected to the tab 221 of the electrode assembly 22. Specifically, the current collecting piece 242 can be connected to the tab 221 by welding.

[0158] The current collecting piece 242 can have a fan shape, so that the shape of the current collecting piece 242 is adapted to the shapes of the current collecting body 240 and the elastic part 241.

[0159] In the technical solution, the side surface of the current collecting sheet 242 away from the end cover 23 is connected with the electrode assembly 22, so that the current of the electrode assembly 22 can be transmitted to the shell through the current collecting sheet 242; the current collecting sheet 242 is spaced from the elastic part 241, so that the spacing area between the current collecting sheet 242 and the elastic part 241 can form a smooth exhaust passage, which is beneficial to the smooth exhaust of the exhaust in the battery monomer 20. In addition, the spacing area is arranged between the current collecting sheet 242 and the elastic part 241, and the current collecting sheet 242 can move relative to the current collecting body 240, which is beneficial to reducing the risk of the electrode assembly 22 being extruded and torn.

[0160] In some embodiments, the current collecting member 24 includes a current collecting body 240, an elastic part 241, a center part 2413, and a current collecting sheet 242. The current collecting sheet 242 and the elastic part 241 are both connected with the circular ring-shaped current collecting body 240, the center part 2413 is connected with the elastic part 241 and located on the inner side of the elastic part 241, and the elastic part 241 and the current collecting sheet 242 are spaced. In this way, the center part 2413 and the elastic part 241 are connected as a whole, and the elastic part 241 and the current collecting sheet 242 are both connected with the current collecting body 240, thereby forming the current collecting member 24.

[0161] In some embodiments, at least one current collecting sheet 242 is welded with the tab 221 of the electrode assembly 22 and forms a plurality of welding parts 2421, and the plurality of welding parts 2421 are arranged along the circumference of the current collecting body 240. Through the arrangement of the plurality of welding parts 2421, it is beneficial to enhance the connection strength between the tab 221 and the current collecting sheet 242.

[0162] As an example, the welding part 2421 can be a welding mark formed by welding the current collecting sheet 242 with the tab 221.

[0163] As an example, the current collecting member 24 includes three current collecting sheets 242, the three current collecting sheets 242 are welded with the tab 221 to form three welding parts 2421, and the three welding parts 2421 are arranged along the circumference of the current collecting body 240.

[0164] As an example, the welding part 2421 has an elliptical structure.

[0165] In some embodiments, the welding part 2421 includes a first welding part 24211 and two second welding parts 24212, the first welding part 24211 is located between the two second welding parts 24212, and the length of the first welding part 24211 is greater than the length of the second welding part 24212. In this way, the arrangement of the first welding part 24211 and the second welding part 24212 is adapted to the shape of the current collecting sheet 242, which is beneficial to the welding between the welding part 2421 and the current collecting sheet 242.

[0166] In some embodiments, 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 at the inner side of the end cover body 231, and the elastic portion 241 abuts against the pressure relief mechanism 26.

[0167] The pressure relief mechanism 26 is an element or component for being actuated when the internal pressure or temperature of the battery cell 20 reaches a predetermined threshold value, to release the internal pressure or temperature of the battery cell 20. The predetermined threshold value can be adjusted according to different design requirements. For example, the predetermined threshold value can depend on the material of one or more of the positive electrode plate, the negative electrode plate, the electrolyte, and the separator in the battery cell.

[0168] "Actuated" means that the pressure relief mechanism 26 generates an action or is activated to a certain state, so that the internal pressure and temperature of the battery cell 20 can be released. The action generated by the pressure relief mechanism 26 can include but is not limited to at least one of the following: the pressure relief mechanism 26 is broken, cracked, torn or opened, etc. When the pressure relief mechanism 26 is actuated, the high-temperature and high-pressure substances in the interior of the battery cell 20 are discharged outward from the actuated part as the discharge. In this way, the battery cell 20 can be pressure-released and temperature-released under controllable pressure or temperature, thereby reducing the risk of a more serious accident.

[0169] The discharge from the battery cell 20 mentioned in the embodiments of the present application includes but is not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, fragments of current collecting members 24, high-temperature and high-pressure gases generated by reactions, flames, etc.

[0170] The pressure relief mechanism 26 can be in a separate structure with the end cover 23, for example, the pressure relief mechanism 26 is an independent component mounted on the end cover 23. The pressure relief mechanism 26 can be a component such as a rupture disc, a burst disc, a gas valve, a pressure relief valve or a safety valve mounted on the end cover 23, and can specifically adopt a pressure-sensitive or temperature-sensitive element or structure.

[0171] The pressure relief mechanism 26 can be in an integrated 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, 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 gas generated by the battery cell 20 is too much to cause the internal pressure to rise and reach a threshold value, or the heat generated by the reaction inside the battery cell 20 causes the internal temperature of the battery cell 20 to rise and reach a threshold value, the pressure relief mechanism 26 can break at the notch to cause the inside and outside of the battery cell 20 to be communicated, and the gas pressure and temperature are released outward through the cracking of the pressure relief mechanism 26, thereby avoiding the explosion of the battery cell 20. As an example, the end cover 23 is provided with a notch groove, and the area defined by the notch groove forms the pressure relief mechanism 26.

[0172] In the technical solution, the pressure relief mechanism 26 is located at the inner side of the end cover body 231, which can reduce the risk of the pressure relief mechanism 26 being damaged due to interference with components other than the battery monomer 20, and is conducive to improving the long-term reliability of the pressure relief mechanism 26; the elastic part 241 abuts against the pressure relief mechanism 26, which facilitates the connection between the elastic part 241 and the end cover 23.

[0173] As an example, the abutting area 2414 of the elastic part 241 abuts against the pressure relief mechanism 26, thereby facilitating the abutment between the elastic part 241 and the end cover 23. In addition, when the pressure relief mechanism 26 is actuated, the exhaust passage (for example, the first interval 2401 and the second interval 2402) formed by the current collecting member 24 can also facilitate the discharge of the exhaust in the battery monomer 20.

[0174] In some embodiments, the pressure relief mechanism 26 is provided with a first protruding part 232, which protrudes towards the electrode assembly 22 along the thickness direction of the end cover 23, and the first protruding part 232 abuts against the abutting area 2414 of the elastic part 241. In this way, the connection between the elastic part 241 and the end cover 23 is achieved.

[0175] As an example, the first protruding part 232 is arranged in the area defined by the pressure relief mechanism 26, and the first protruding part 232 abuts against the abutting area 2414 of the elastic part 241. In this way, the position of the first protruding part 232 corresponds to the abutting area 2414, and the first protruding part 232 is far away from the edge of the end cover 23, which facilitates the processing of the first protruding part 232.

[0176] Figure 11 The structure of the end cover of an embodiment of the present application is shown in the figure. In some embodiments, for example, in combination with the figures shown in Figure 7 and Figure 11 As shown, the end cover 23 is provided with a score groove 261, and the area defined by the score groove 261 forms the pressure relief mechanism 26. The first protruding part 232 is located at the inner side of the score groove 261 and is arranged in a spaced manner with the score groove 261.

[0177] As an example, the score groove 261 is annular with a notch. The thickness of the area of the end cover 23 provided with the score groove 261 is smaller than the thickness of the area not provided with the score groove 261, so that the end cover 23 is broken at the score groove 261 when thermal runaway occurs.

[0178] In the above embodiments, the first protruding part 232 is arranged in a spaced manner with the score groove 261, which facilitates the preparation of the score groove 261 and can reduce the adverse effects of the precision of the score groove 261. In addition, the provision of the score groove 261 is also conducive to reducing the risk of interference between the pressure relief mechanism 26 and structures other than the battery monomer 20.

[0179] In some embodiments, the current collecting member 24 is welded with the shell 21. The current collecting member 24 can be directly welded with the shell 21, or can be welded with the shell 21 through a special structure provided on the current collecting member 24.

[0180] Figure 12 An exploded schematic view of a structure of a battery cell according to another embodiment of the present application, Figure 13 A schematic view of a structure of a battery cell according to another embodiment of the present application, Figure 14 A cross-sectional view of the battery cell in Figure 13 A schematic view of a structure of a battery cell according to another embodiment of the present application, Figure 15 A schematic view of a structure of a battery cell according to another embodiment of the present application, Figure 14 An enlarged schematic view of the region C in

[0181] In some embodiments, the current collecting member 24 is welded with the shell 21. The current collecting member 24 can be directly welded with the shell 21, or can be welded with the shell 21 through a special structure provided on the current collecting member 24. Figures 12 to 15 As shown in FIG. 2, the inner side surface of the shell 21 is provided with a limiting portion 212, and the current collecting member 24 abuts against the limiting portion 212, and the tab 221 of the electrode assembly 22 is electrically connected with the shell 21 through the current collecting member 24.

[0182] The inner side surface of the shell 21 refers to the inner side surface of the side wall of the shell 21 extending along the thickness direction of the end cover 23. Understandably, the inner side surface extends substantially along the thickness direction of the end cover 23. In the embodiment in which the shell 21 is a cylinder, the inner side surface of the shell 21 is a cylindrical surface. In the embodiment in which the shell 21 is a cuboid, the inner side surface of the shell 21 includes four side surfaces located at different positions and connected in sequence.

[0183] The inner side surface of the shell 21 is provided with the limiting portion 212. Understandably, the limiting portion 212 protrudes from the inner side surface. The limiting portion 212 is a structure for limiting the movement of the end cover 23 towards the electrode assembly 22. The current collecting member 24 abuts against the side of the limiting portion 212 facing the electrode assembly 22, and the current collecting member 24 is located at the side of the electrode assembly 22 facing the end cover 23. Understandably, in the thickness direction of the end cover 23, the limiting portion 212 is located between the electrode assembly 22 and the end cover 23. The limiting portion 212 and the shell 21 can be an integrally formed structure, or can be a structure formed separately and then connected together, for example, the limiting portion 212 is welded with the shell 21. The limiting portion 212 can have various structures, for example, the limiting portion 212 is a boss protruding from the inner side surface of the shell 21, or for example, the limiting portion 212 is an annular structure extending along the circumferential direction of the shell 21.

[0184] Through the provision of the limiting portion 212, the end cover 23 can be limited, and the current collecting member 24 can also be limited, so that the current collecting member 24 can limit the movement of the electrode assembly 22, reduce the displacement of the electrode assembly 22 in the shell 21 along the thickness direction of the end cover 23, and reduce the risk of the connection between the tab of the electrode assembly 22 and the current collecting member 24 being invalid due to the excessive displacement of the electrode assembly 22.

[0185] In some embodiments, the end cover 23 is welded to the shell 21.

[0186] In some embodiments, the battery cell 20 further includes a current collector 27. The current collector 27 can have a different structure from the current collector member 24, and the current collector 27 can be a disc. The current collector 27 and the current collector member 24 are respectively located at two ends of the shell 21 and connected to electrodes of opposite polarity. As an example, the current collector 27 is connected to a positive electrode tab, and the current collector member 24 is connected to a negative electrode tab.

[0187] In some embodiments, the battery cell 20 further includes an insulating member 28 for isolating the electrode terminal 25 from the shell 21.

[0188] In some embodiments, the negative electrode active material includes at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, a silicon-containing alloy, or a silicon-oxygen-carbon composite material. In this way, the battery cell can have a higher energy density.

[0189] 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: 1wt%≤A≤15wt%; optionally, 2wt%≤A≤8wt%. For example, A is 1wt%, 2wt%, 3wt%, 6wt%, 8wt%, 15wt%, or any value within the above range.

[0190] In addition to the negative electrode active material, the negative electrode film layer can optionally include a conductive agent and a binder.

[0191] As an example, the conductive agent in the negative electrode film layer can include one or more of super conductive carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0192] As an example, the binder in the negative electrode film layer can include one or more of styrene butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (e.g., polyacrylic acid PAA, polymethylacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0193] In some embodiments, the negative electrode active material can further include other auxiliary agents. As an example, the other auxiliary agents can include a thickening agent, such as sodium carboxymethyl cellulose (CMC), PTC thermistor material, etc.

[0194] As an example, the mass of silicon in the negative electrode active material can be tested by inductively coupled plasma emission spectrometry (ICP).

[0195] In the negative active material, the silicon element has a suitable mass content, so that the electrode assembly 22 has a relatively suitable expansion rate, facilitating normal use of the battery monomer 20.

[0196] In some embodiments, the positive electrode sheet includes a positive active material, the chemical formula of the positive 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.

[0197] a can be -0.1, -0.04, 0, 0.04, 0.1 or any value within the above range, x can be 0.7, 0.75, 0.8, 0.9, 0.95, 0.96 or any value within the above range, y can be 0.1, 0.2 or any value within the above range, z can be 0.1, 0.2 or any value within the above range, b can be 0, 0.1, 0.2 or any value within the above range. As an example, b is 0, the positive active material includes LiNi 0.8 Co 0.1 Mn 0.1 O2. As another example, b>0, the positive active material includes LiNi 0.7 Co 0.1 Mn 0.1 Al 0.1 O2.

[0198] The positive active material satisfying the above chemical formula can be referred to as a high-nickel ternary material, and the high-nickel ternary material is matched with the silicon-containing negative active material, which is beneficial to improve the energy density of the battery monomer. In addition, compared with a ternary material with a lower nickel content or a material such as lithium iron phosphate, the high-nickel ternary material has a higher gram capacity, so that under the same capacity, the use of the high-nickel ternary material is beneficial to reduce the total mass of the positive active material, thereby being beneficial to further improve the energy density of the battery monomer.

[0199] It should be noted that the battery cell will be accompanied by Li deintercalation and consumption during the charging and discharging process, and the molar content of Li is different when the battery cell is discharged to different states. In the enumeration of the positive active material in the embodiments of the present application, the molar content of Li is the initial state of the material, and the positive active material is applied to the battery system. After charging and discharging cycle, the molar content of Li will change. In the enumeration of the positive active material in the embodiments of the present application, the molar content of O is only the theoretical state value, and the lattice oxygen release will cause the change of the molar content of oxygen. The actual molar content of O will appear to be floating.

[0200] In some embodiments, the positive active material includes at least one of 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 O2.

[0201] In some embodiments, the negative active material includes a composite material of silicon and graphite, or a mixture of silicon and graphite. Among them, the graphite can be natural graphite or artificial graphite.

[0202] As an example, the negative active material is a mixture of silicon-carbon material and artificial graphite, wherein the mass content of artificial graphite is about 95%, the mass content of silicon-carbon material is about 5%, and the mass ratio of silicon in the silicon-carbon material is about 50%, based on the total mass of the negative active material.

[0203] As an example, the positive active material is LiNi 0.90 Co 0.06 Mn 0.04 O2, and the negative active material is a mixture of silicon-carbon material and graphite. Further, as another example, the positive active material is LiNi 0.90 Co 0.06 Mn 0.04 O2, and the negative active material is a mixture of silicon-carbon material and graphite, and the mass content of artificial graphite is about 95%, the mass content of silicon-carbon material is about 5%, and the mass ratio of silicon in the silicon-carbon material is about 50%, based on the total mass of the negative active material.

[0204] In the above embodiments, the arrangement of the positive active material and the negative active material can make the battery cell 20 have a higher energy density.

[0205] In some embodiments, the material of the shell 21 comprises carbon steel or stainless steel.

[0206] The use of carbon steel or stainless steel can reduce the risk of corrosion of the shell 21 by electrolyte. For example, in some embodiments, the shell 21 is electrically connected to the negative tab, and the shell 21 is in a low potential state. The steel shell 21 is not easily corroded by electrolyte in the low potential state.

[0207] In some embodiments, the battery cell 20 is a cylindrical battery cell 20. In this way, the shape of the current collecting member 24 is adapted to the shape of the battery cell 20, facilitating assembly of the battery cell 20.

[0208] In some embodiments, the shell 21 comprises a barrel 210 and a cover 211 connected to the barrel 210. The cover 211 and the barrel 210 are integrally formed or separately formed. The barrel 210 surrounds the outer periphery of the electrode assembly 22. The cover 211 is provided with an electrode lead-out hole 2111. The battery cell 20 further comprises an electrode terminal 25, which is insulated and arranged in the electrode lead-out hole 2111.

[0209] As an example, the cover 211 and the barrel 210 are integrally formed.

[0210] As another example, the cover 211 and the barrel 210 are separately formed. The cover 211 can be disc-shaped, and the barrel 210 can be cylindrical.

[0211] In this embodiment, one of the shell 21 and the electrode terminal 25 is the positive output terminal of the battery cell 20, and the other is the negative output terminal of the battery cell 20. At least part of the shell 21 itself can serve as one output terminal of the battery cell 20, so that one electrode terminal can be omitted, which is beneficial to simplify the structure of the battery cell 20.

[0212] The embodiments of the present application provide a battery, which comprises the battery cell 20 in any of the above embodiments.

[0213] The embodiments of the present application provide a use electric device, which comprises the battery in any of the above embodiments.

[0214] In an embodiment of the present application, the battery cell 20 comprises an electrode assembly 22, a housing 21, an end cover 23 and a current collecting member 24. The housing 21 is used to accommodate the electrode assembly 22 and the current collecting member 24, and the housing 21 has an opening, and the end cover 23 is used to cover the opening. The current collecting member 24 is connected with 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 active material in the battery cell 20 comprises silicon element, and the battery cell 20 has high energy density and high expansion. The current collecting member 24 comprises a current collecting body 240 and an elastic part 241, the current collecting body 240 is annular structure, the elastic part 241 is located at the inner side of the current collecting body 240 and connected with the current collecting body 240, the elastic part 241 protrudes from the current collecting body 240 and abuts against the end cover 23. Through the above arrangement, the battery cell 20 has high energy density, and the influence of high expansion rate of the active material on the battery cell 20 can be reduced, the electrode assembly 22 is extruded, so that the risk of powder falling and lithium precipitation is low, and the battery cell 20 has high reliability and high energy density.

[0215] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to the application without departing from the scope thereof, and equivalent parts can be substituted therefor. In particular, the technical features mentioned in each of the embodiments can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: Electrode assembly (22) includes a negative electrode sheet, the negative electrode sheet including a negative electrode active material capable of reversibly extracting and inserting metal ions, the negative electrode active material including silicon element; The housing (21) is provided with an opening, and the housing (21) is used to accommodate the electrode assembly (22); End cap (23) that covers the opening; A current collector (24) is housed within the housing (21) and located on the side of the electrode assembly (22) facing the end cap (23). The current collector (24) is 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 part (241). The current collecting body (240) is an annular structure. The elastic part (241) is located inside the current collecting body (240) and connected to the current collecting body (240). At least a portion of the elastic part (241) protrudes from the current collecting body (240) along the thickness direction of the end cap (23) and abuts against the end cap (23). The current collection member (24) also includes a central portion (2413), which is located inside the elastic portion (241).

2. The battery cell according to claim 1, characterized in that, The elastic part (241) can deform during the charging and discharging process of the battery cell.

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

4. The battery cell according to claim 1, characterized in that, The central portion (2413) abuts against the tab (221) of the electrode assembly (22).

5. The battery cell according to claim 1, characterized in that, The elastic part (241) includes a first piece (2411) and a second piece (2412). The first piece (2411) is connected to the inner side of the current collection body (240) and extends obliquely toward the end cap (23). The second piece (2412) is connected to the outer side of the center part (2413) and extends obliquely toward the end cap (23). The first piece (2411) and the second piece (2412) are connected at an angle greater than 0° and less than 180° to form an abutment area (2414), which abuts against the end cap (23).

6. The battery cell according to claim 5, characterized in that, The end cap (23) includes an end cap body (231) and a first protrusion (232), the first protrusion (232) protruding toward the electrode assembly (22) along the thickness direction of the end cap (23), and the first protrusion (232) abutting against the abutting area (2414).

7. The battery cell according to claim 5, characterized in that, The elastic part (241) is provided with a first through hole (2415) extending through the elastic part (241) along the thickness direction of the elastic part (241), and the first through hole (2415) extends from the first piece (2411) to the second piece (2412).

8. The battery cell according to claim 1, characterized in that, There are multiple elastic parts (241), and each elastic part (241) is arranged at circumferential intervals along the current collection body (240).

9. The battery cell according to claim 8, characterized in that, The current collecting component (24) further includes a current collecting plate (242) connected to the current collecting body (240). A current collecting plate (242) is provided between two adjacent elastic parts (241). The side surface of the current collecting plate (242) facing away from the end cap (23) is connected to the tab (221) of the electrode assembly (22), and the current collecting plate (242) and the elastic part (241) are spaced apart.

10. The battery cell according to claim 9, characterized in that, At least one of the current collector plates (242) is welded to the tab (221) of the electrode assembly (22) to form a plurality of welded portions (2421), the plurality of welded portions (2421) being arranged circumferentially spaced along the current collector body (240).

11. The battery cell according to claim 10, characterized in that, The welding part (2421) includes a first welding part (24211) and two second welding parts (24212). The first welding part (24211) is located between the two second welding parts (24212), and the length of the first welding part (24211) is greater than the length of the second welding parts (24212).

12. The battery cell according to claim 1, characterized in that, The end cap (23) is provided with an end cap body (231) and a pressure relief mechanism (26). The pressure relief mechanism (26) is located inside the end cap body (231), and the elastic part (241) abuts against the pressure relief mechanism (26).

13. The battery cell according to claim 12, 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 cap (23), and the first protrusion (232) abuts against the contact area (2414) of the elastic part (241).

14. The battery cell according to claim 13, characterized in that, The end cap (23) is provided with a groove (261), and the area defined by the groove (261) forms the pressure relief mechanism (26). The first protrusion (232) is located inside the groove (261) and is spaced apart from the groove (261).

15. The battery cell according to claim 1, characterized in that, The inner side of the housing (21) is provided with a limiting part (212), the current collecting member (24) abuts against the limiting part (212), and the electrode tab (221) of the electrode assembly (22) is electrically connected to the housing (21) through the current collecting member (24).

16. The battery cell according to claim 15, characterized in that, The current collection component (24) is welded to the housing (21).

17. The battery cell according to claim 1, characterized in that, The shell (21) is made of carbon steel or stainless steel.

18. The battery cell according to claim 1, characterized in that, The battery cell is cylindrical.

19. The battery cell according to any one of claims 1-18, characterized in that, The housing (21) includes a cylindrical body (210) and a cover (211) connected to the cylindrical body (210). The cover (211) and the cylindrical body (210) are integral or separate structures. The cylindrical body (210) is arranged around the outer periphery of the electrode assembly (22). The cover (211) is provided with an electrode lead-out hole (2111). The battery cell also includes an electrode terminal (25), which is insulated from the electrode lead-out hole (2111).

20. A battery, characterized in that, include: The battery cell as described in any one of claims 1-19.

21. An electrical appliance, characterized in that, include: The battery as claimed in claim 20.

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