Battery cell, battery apparatus, and electric device

Abstract

A battery cell (20), a battery apparatus (100), and an electric device. The battery cell (20) comprises a casing (2) and an electrode assembly (24). The casing (2) comprises a side wall (211) and a first wall (23), the side wall (211) being disposed around the first wall (23). The first wall (23) comprises a body portion (231) and a connection portion (232) connected to each other, wherein the body portion (231) is connected to the side wall (211), and the body portion (231) and the connection portion (232) are made of different materials. The electrode assembly (24) is accommodated in the casing (2), and the electrode assembly (24) is provided with a first tab (242). The connection portion (232) and the first tab (242) are made of the same material, and the connection portion (232) is connected to the first tab (242) by means of welding. The first wall (23) is configured to comprise the body portion (231) and the connection portion (232) connected to each other, and the connection portion (232) is connected to the first tab (242) by means of welding, such that the input or output of electric energy to / from the battery cell (20) can be realized by means of the first wall (23), the number of electrode terminals and the number of current collecting members can be reduced, the space occupied inside the battery cell (20) can be reduced, and energy density can be improved. The connection portion (232) and the first tab (242) are welded using the same material, such that the occurrence of welding cracks between the first wall (23) and the first tab (242) can be reduced, thereby improving the reliability of the battery cell (20).

Description

Battery cells, battery devices and electrical equipment

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese patent application filed on July 10, 2024, entitled “Battery Cell, Battery Device and Electrical Equipment” (application number: 2024216304735), the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] Batteries are widely used in the new energy field, such as in electric vehicles and new energy vehicles, which have become a new trend in the automotive industry. The development of battery technology must consider multiple design factors simultaneously, such as battery life, discharge capacity, and charge / discharge rate. Additionally, battery energy density also needs to be considered. However, the energy density of current batteries is relatively low.

[0005] Summary of the Invention

[0006] The purpose of this application is to provide a battery cell, a battery device, and an electrical appliance, which aims to improve the problem of low energy density of batteries in related technologies.

[0007] In a first aspect, embodiments of this application provide a battery cell, the battery cell including a housing and an electrode assembly, the housing including a side wall and a first wall, the side wall surrounding the first wall; the electrode assembly being housed within the housing, the electrode assembly having a first tab; wherein, the first wall includes a body portion and a connecting portion connected to each other, the body portion being connected to the side wall, the material of the body portion being different from the material of the connecting portion, the material of the connecting portion being the same as the material of the first tab, and the connecting portion being welded to the first tab.

[0008] In the above technical solution, by setting the first wall as an interconnected body and a connecting part, with the connecting part welded to the first electrode tab and the body connected to the side wall, an electrical connection between the electrode assembly and the first wall is achieved, thereby enabling the input or output of electrical energy from the battery cell through the first wall. On one hand, this reduces the number of electrode terminals and current collectors, lowering costs, reducing the space occupied within the battery cell, and increasing energy density. On the other hand, once the information acquisition device is electrically connected to the first wall, it can collect usage information from the battery cell, facilitating connection of the information acquisition device to the battery cell and data acquisition, reducing the difficulty of data acquisition from the battery cell, and further reducing manufacturing costs. In addition, by setting the material of the connecting part to be the same as that of the first electrode tab, on the one hand, it is easier to weld the connecting part to the first electrode tab, which helps to reduce the assembly difficulty between the first wall and the first electrode tab of the electrode assembly, thereby improving the assembly efficiency of the battery cell. On the other hand, it enables the first wall and the first electrode tab to be welded together with the same material, which can alleviate the phenomenon of different melting points and different coefficients of thermal expansion caused by welding the first wall and the first electrode tab with different materials. This can reduce the phenomenon of welding cracks between the first wall and the first electrode tab, which helps to reduce the risk of leakage of the battery cell and improve the reliability of the battery cell.

[0009] As an optional technical solution in this application embodiment, the body portion has an inner surface facing the electrode assembly, the body portion is provided with a receiving cavity, the receiving cavity extends to the inner surface, and the connecting portion is at least partially received within the receiving cavity.

[0010] In the above technical solution, the receiving cavity is recessed from the inner surface of the main body towards the first wall away from the electrode assembly. By at least partially accommodating the connecting part in the receiving cavity, the occupancy of the connecting part on the internal space of the battery cell is further reduced, which is beneficial to improving the energy density of the battery cell.

[0011] As an optional technical solution in this application embodiment, the receiving cavity is a receiving groove that is recessed from the inner surface in a direction away from the electrode assembly.

[0012] In the above technical solution, when the receiving cavity is a receiving tank located in the body, the electrolyte is less likely to leak from the receiving tank, which helps to reduce the risk of leakage of the battery cell and improve the reliability of the battery cell.

[0013] As an optional technical solution in this application embodiment, the body part further includes an outer surface opposite to the inner surface, and the receiving cavity is a through hole penetrating the inner surface and the outer surface.

[0014] In the above technical solution, when the receiving cavity is a through hole that penetrates the inner and outer surfaces, it is convenient to connect the connecting part and the first electrode tab by through welding, which helps to reduce the assembly difficulty between the first wall and the first electrode tab of the electrode assembly, thereby improving the assembly efficiency of the battery cell.

[0015] As an optional technical solution in this application embodiment, the connecting part is completely accommodated within the accommodating cavity.

[0016] In the above technical solution, by making the connecting part completely accommodated in the cavity, it is beneficial to reduce the space occupied by the connecting part in the internal space of the battery cell and to improve the energy density of the battery cell.

[0017] As an optional technical solution in this application embodiment, the surface of the connecting portion facing the electrode assembly is flush with the inner surface.

[0018] In the above technical solution, by making the surface of the connecting part facing the electrode assembly flush with the inner surface of the body part, it is possible to reduce the space occupied by the connecting part in the internal space of the battery cell, which is beneficial to improving the energy density of the battery cell, and also facilitates the welding of the connecting part and the first electrode tab, which is beneficial to improving the welding quality of the connecting part and the first electrode tab.

[0019] As an optional technical solution in this application embodiment, the outer peripheral surface of the connecting part is welded to the cavity wall surface of the receiving cavity.

[0020] In the above technical solution, when the outer peripheral surface of the connecting part is welded to the cavity wall, high welding quality can be achieved simply by matching the shape and size of the connecting part with the shape and size of the cavity. Matching the shape and size of the connecting part with the shape and size of the cavity is relatively simple. Therefore, welding the outer peripheral surface of the connecting part to the cavity wall improves welding quality. Furthermore, butt welding can be used when welding the outer peripheral surface of the connecting part to the cavity wall. Butt welding requires less heat, making the connecting part and the main body less prone to deformation during welding, thus further improving welding quality.

[0021] As an optional technical solution in this application embodiment, the connecting portion protrudes from the inner surface along the direction of the first wall toward the electrode assembly.

[0022] In the above technical solution, by making the connecting part protrude out of the receiving cavity, it is convenient to weld the part of the connecting part protruding out of the receiving cavity to the first electrode ear.

[0023] As an optional technical solution in this application embodiment, the outer peripheral surface of the connecting part is welded to the inner surface.

[0024] In the above technical solution, by welding the inner surface of the body part to the outer peripheral surface of the connecting part, the body part and the connecting part are connected by fillet weld, so as to realize the welded connection between the body part and the connecting part. The first wall with this structure can achieve a greater penetration depth at a lower welding power, which is beneficial to improving the welding effect between the connecting part and the body part, thereby effectively improving the connection stability between the connecting part and the body part.

[0025] As an optional technical solution in this application embodiment, the connecting part is welded to the electrode tab to form a first solder mark. Along the thickness direction of the first wall, the connecting part and the electrode tab are stacked, and the electrode tab and the connecting part have an overlapping area, with the first solder mark located in the overlapping area.

[0026] In the above technical solution, the welding connection and the first electrode tab can be penetrated from the side of the first wall away from the electrode assembly, which helps to reduce the welding difficulty and improve the welding quality.

[0027] As an optional technical solution in this application embodiment, the first electrode is a negative electrode.

[0028] In the above technical solution, when the first tab is a negative tab, the first wall can serve as the negative electrode of the battery cell, so as to realize the input or output of electrical energy of the battery cell.

[0029] As an optional technical solution in this application embodiment, the material of the connecting part includes copper, and the material of the body part includes iron.

[0030] In the above technical solution, the connecting part and the first electrode are made of the same material, both of which are copper. The body part is made of iron to give it higher strength, thereby helping to resist external forces and protect the internal components of the battery cell.

[0031] As an optional technical solution in this application embodiment, the battery cell includes an electrode terminal, which is insulated from the housing; the electrode assembly further includes a second tab, which has the opposite polarity to the first tab, and is electrically connected to the electrode terminal.

[0032] In the above technical solution, the first wall can be electrically connected to the first electrode tab, the electrode terminal can be electrically connected to the second electrode tab, the first wall can serve as the positive or negative electrode of the battery cell, and the electrode terminal can serve as the negative or positive electrode of the battery cell, so as to output the electrical energy of the battery cell.

[0033] As an optional technical solution in this application embodiment, the outer shell includes a housing and an end cap, the housing having an opening; the end cap is connected to the housing and closes the opening; wherein, the first wall is the end cap, and the body portion is connected to the housing.

[0034] In the above technical solution, when the end cap is the first wall, the connecting part is welded to the first pole lug and the main body is welded to the shell, which facilitates assembly and makes manufacturing simple and convenient.

[0035] As an optional technical solution in this application embodiment, both the body and the shell are made of steel.

[0036] In the above technical solution, by making the body and casing of steel, the high strength of steel provides greater strength to the casing, thus helping to resist external forces and protect the internal components of the battery cell. Furthermore, the body and casing are welded together using the same material, mitigating the differences in melting points and coefficients of thermal expansion caused by welding materials that are different. This reduces the likelihood of welding cracks between the body and casing, thus lowering the risk of leakage from the battery cell and improving its reliability.

[0037] As an optional technical solution in this application embodiment, the battery cell is a cylindrical battery cell.

[0038] Secondly, embodiments of this application also provide a battery device, which includes the aforementioned battery cell.

[0039] Thirdly, embodiments of this application also provide an electrical device, the electrical device including the aforementioned battery cell, the battery cell being used to provide electrical energy to the electrical device. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 is a structural schematic diagram of a vehicle provided in some embodiments of this application;

[0042] Figure 2 is an exploded view of a battery device provided in some embodiments of this application;

[0043] Figure 3 is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0044] Figure 4 is an exploded view of a single battery cell provided in some embodiments of this application;

[0045] Figure 5 is an exploded view of the first wall provided in some embodiments of this application;

[0046] Figure 6 is a partial cross-sectional view of a battery cell provided in some embodiments of this application;

[0047] Figure 7 is a schematic diagram of the structure of a battery cell provided in some other embodiments of this application;

[0048] Figure 8 is a partial cross-sectional view of a battery cell provided in some other embodiments of this application;

[0049] Figure 9 is a partial cross-sectional view of a battery cell provided in some embodiments of this application.

[0050] Icons: 10-Box; 11-First part; 12-Second part; 20-Battery cell; 2-Outer shell; 21-Shell; 211-Side wall; 212-Bottom wall; 22-End cap; 23-First wall; 231-Main body; 2311-Inner surface; 2312-Receiving cavity; 232-Connecting part; 2321-Outer peripheral surface; 24-Electrode assembly; 241-Main body; 242-First tab; 243-Second tab; 25-First solder mark; 26-Second solder mark; 100-Battery device; 200-Controller; 300-Motor; 1000-Vehicle. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0053] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0054] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0055] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0056] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0057] In this application, "multiple" means two or more (including two).

[0058] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0059] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0060] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0061] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0062] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0063] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0064] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05At least one of O2 and its modified compounds.

[0065] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0066] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0067] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0068] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0069] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0070] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0071] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0072] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0073] In some embodiments, the separator is a separator membrane. The separator membrane can be of various types, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0074] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0075] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0076] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0077] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0078] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0079] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0080] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0081] As an example, polymer solid electrolytes can be polyether (polyoxyethylene), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0082] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0083] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0084] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0085] In some implementations, the electrode assembly is a stacked structure.

[0086] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0087] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0088] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0089] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0090] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0091] In some embodiments, the electrode assembly can be cylindrical, flat, or polygonal, etc.

[0092] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0093] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0094] As an example, a battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include, but are not limited to, square battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0095] The battery device mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity.

[0096] In some embodiments, the battery device can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0097] In some embodiments, the battery device may be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0098] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0099] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0100] Batteries are widely used in the new energy field, such as in electric vehicles and new energy vehicles, which have become a new trend in the automotive industry. The development of battery technology must consider multiple design factors simultaneously, such as battery life, discharge capacity, and charge / discharge rate. Additionally, battery energy density also needs to be considered. However, the energy density of current batteries is relatively low.

[0101] In existing technologies, current collectors are typically used to connect the electrode terminals and the tabs of the electrode assembly to achieve the input or output of electrical energy in a single battery cell. However, both the electrode terminals and the current collectors occupy internal space within the battery cell, resulting in a lower energy density for the battery cell.

[0102] Therefore, this application provides a battery cell, which includes a casing and an electrode assembly. The casing includes a sidewall and a first wall, with the sidewall surrounding the first wall. The first wall includes a body portion and a connecting portion connected to each other. The body portion is connected to the sidewall, and the materials of the body portion and the connecting portion are different. The electrode assembly is housed within the casing and has a first electrode tab. The connecting portion is made of the same material as the first electrode tab, and the connecting portion is welded to the first electrode tab.

[0103] By configuring the first wall as an interconnected body and connecting part, with the connecting part welded to the first electrode tab and the body connected to the side wall, an electrical connection between the electrode assembly and the first wall is achieved, enabling the input or output of electrical energy from the battery cell through the first wall. On one hand, this reduces the number of electrode terminals and current collectors, lowering costs, reducing the space occupied within the battery cell, and increasing energy density. On the other hand, once the information acquisition device is electrically connected to the first wall, it can collect usage information from the battery cell, facilitating connection of the device to the battery cell and data acquisition, reducing the difficulty of data collection from the battery cell, and further lowering manufacturing costs. In addition, by setting the material of the connecting part to be the same as that of the first electrode tab, on the one hand, it is easier to weld the connecting part to the first electrode tab, which helps to reduce the assembly difficulty between the first wall and the first electrode tab of the electrode assembly, thereby improving the assembly efficiency of the battery cell. On the other hand, it enables the first wall and the first electrode tab to be welded together with the same material, which can alleviate the phenomenon of different melting points and different coefficients of thermal expansion caused by welding the first wall and the first electrode tab with different materials. This can reduce the phenomenon of welding cracks between the first wall and the first electrode tab, which helps to reduce the risk of leakage of the battery cell and improve the reliability of the battery cell.

[0104] The technical solutions described in the embodiments of this application are applicable to batteries and electrical devices that use batteries.

[0105] Electrical equipment can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical equipment.

[0106] For ease of explanation, the following embodiments will use a vehicle 1000 as an example of electrical equipment.

[0107] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 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 battery device 100 is installed inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0108] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0109] Please refer to Figure 2, which is an exploded view of a battery device 100 provided in some embodiments of this application. The battery device 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 jointly define the space. Alternatively, the first portion 11 and the second portion 12 may both be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0110] In the battery device 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel connections. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can also consist of multiple battery cells 20 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is also housed within the housing 10. The battery device 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0111] Each battery cell 20 can be a secondary battery cell or a primary battery cell; it can also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0112] Please refer to Figures 3, 4, 5, and 6. Figure 3 is a structural schematic diagram of a battery cell 20 provided in some embodiments of this application. Figure 4 is an exploded view of a battery cell 20 provided in some embodiments of this application. Figure 5 is an exploded view of a first wall 23 provided in some embodiments of this application. Figure 6 is a partial cross-sectional view of a battery cell 20 provided in some embodiments of this application. This application provides a battery cell 20, which includes a housing 2 and an electrode assembly 24. The housing 2 includes a side wall 211 and a first wall 23, with the side wall 211 surrounding the first wall 23. The first wall 23 includes a body portion 231 and a connecting portion 232 connected to each other. The body portion 231 is connected to the side wall 211, and the materials of the body portion 231 and the connecting portion 232 are different. The electrode assembly 24 is housed within the housing 2 and has a first tab 242. The connecting portion 232 is made of the same material as the first tab 242, and the connecting portion 232 is welded to the first tab 242.

[0113] Battery cell 20 refers to the smallest unit that makes up battery device 100.

[0114] The outer casing 2 includes an end cap 22 and a housing 21, the housing 21 having an opening, and the end cap 22 being connected to the housing 21 and closing the opening.

[0115] End cap 22 refers to a component that covers the opening of housing 21 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 22 can be adapted to the shape of housing 21 to fit it. Optionally, end cap 22 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 22 is less prone to deformation under pressure and impact, enabling battery cell 20 to have higher structural strength and improved safety performance. The material of end cap 22 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, battery cell 20 also includes an insulating member disposed inside end cap 22. The insulating member can be used to isolate the electrical connection portion 232 within housing 21 from end cap 22 to reduce the risk of short circuit. For example, the insulating member can be plastic, rubber, etc.

[0116] The housing 21 is a component used to cooperate with the end cap 22 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 24, electrolyte, and other components. The housing 21 and the end cap 22 can be independent components. An opening can be provided on the housing 21, and the end cap 22 closes the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 22 and the housing 21 can be integrated. Specifically, the end cap 22 and the housing 21 can form a common mating surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 21, the end cap 22 closes the housing 21. The housing 21 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode assembly 24. The material of the housing 21 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special limitations on this.

[0117] Electrode assembly 24 is the component in the battery cell 20 where electrochemical reactions occur. The casing 2 may contain one or more electrode assemblies 24. Electrode assembly 24 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body 241 of the electrode assembly 24, while the portions of the positive and negative electrode sheets without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body 241 or separately at both ends of the main body 241. During the charging and discharging process of the battery device 100, the positive and negative active materials react with the electrolyte.

[0118] In embodiments where the housing 21 has an opening at only one end, the end cap 22 can serve as the first wall 23, and the side wall 211 can be part of the housing 21. Alternatively, the bottom wall 212 of the housing 21 opposite to the end cap 22 can serve as the first wall 23, with the side wall 211 and the first wall 23 integrally formed to constitute the housing 21. In embodiments where both opposite ends of the housing 21 have openings, one of the two end caps 22 can serve as the first wall 23, and the side wall 211 can be the housing 21.

[0119] The sidewall 211 can be cylindrical, making the battery cell 20 a cylindrical battery cell; the sidewall 211 can also be cuboid, making the battery cell 20 a prismatic battery cell or a blade battery cell. The sidewall 211 and the first wall 23 can be integrally formed, constituting the housing 21, with the end of the sidewall 211 away from the first wall 23 forming an opening in the housing 21; alternatively, the sidewall 211 and the first wall 23 can be separate components, with the first wall 23 serving as an end cap 22, and the end of the sidewall 211 near the first wall 23 forming an opening in the housing 21. In embodiments where the sidewall 211 and the first wall 23 are separate components, the first wall 23 and the sidewall 211 can be connected by welding, bonding, or roll sealing.

[0120] The body portion 231 is the part of the first wall 23 used to connect with the side wall 211. The connecting portion 232 is the part of the first wall 23 used to weld with the first electrode 242 to achieve electrical connection with the first electrode 242. The body portion 231 and the connecting portion 232 are connected, and the connection method between the connecting portion 232 and the body portion 231 can be various, such as snap-fit, bolted connection, laser welding connection, plating connection, friction welding connection, or ultrasonic connection, etc.

[0121] The material of the body portion 231 is different from that of the connecting portion 232; that is, the main components of the body portion 231 and the connecting portion 232 are different. Specifically, the main component of the body portion 231 is the component comprising 50% or more of its composition, and similarly, the main component of the connecting portion 232 is the component comprising 50% or more of its composition. The connecting portion 232 can also be made of various materials, such as copper or aluminum. If the first electrode tab 242 is a positive electrode tab, then the material of the first electrode tab 242 is usually aluminum. Since the material of the connecting portion 232 is the same as that of the first electrode tab 242, the main component of the connecting portion 232 is aluminum, and its content is 50% or more. If the first electrode tab 242 is a negative electrode tab, then the material of the first electrode tab 242 is usually copper. Since the material of the connecting portion 232 is the same as that of the first electrode tab 242, the main component of the connecting portion 232 is copper, and its content is 50% or more. In other words, the difference in material between the connecting part 232 and the body part 231 means that the main components of the connecting part 232 and the body part 231 are different. For example, if both the connecting part 232 and the body part 231 are made of a single material, such as copper or aluminum, then the connecting part 232 and the body part 231 are composed of different metallic elements. If the connecting part 232 and the body part 231 are made of an alloy or mixed material, such as aluminum alloy or steel, then the difference in material between the connecting part 232 and the body part 231 means that their main components are different, that is, the components with a content of more than 50% in the alloy or mixed material are different. Optionally, the material of the body part 231 can be iron, aluminum, steel, or aluminum alloy, etc.

[0122] The first tab 242 can be either a positive or a negative tab. When the first tab 242 is a positive tab, the first wall 23 can serve as the positive electrode of the battery cell 20. When the first tab 242 is a negative tab, the first wall 23 can serve as the negative electrode of the battery cell 20.

[0123] The material of the first tab 242 is the same as that of the connecting part 232; that is, the main components of the first tab 242 and the connecting part 232 are the same. Specifically, the main component of the first tab 242 comprises 50% or more of its components, and similarly, the main component of the connecting part 232 comprises 50% or more of its components. The material of the first tab 242 can also be various, such as copper or aluminum. If the first tab 242 is a positive tab, its material is usually aluminum, and the main component of the connecting part 232 is also aluminum, with a content of 50% or more. If the first tab 242 is a negative tab, its material is usually copper, and the main component of the connecting part 232 is also copper, with a content of 50% or more. In other words, the fact that the material of the connecting part 232 is the same as that of the first electrode 242 means that the main components of the connecting part 232 are the same as those of the first electrode 242. For example, if the connecting part 232 and the first electrode 242 are both made of a single material, such as copper or aluminum, then the materials of the connecting part 232 and the first electrode 242 are composed of the same metallic elements. If the connecting part 232 and the first electrode 242 are made of an alloy or mixed material, such as aluminum alloy or steel, then the materials of the connecting part 232 and the first electrode 242 are different because the main components of the connecting part 232 and the first electrode 242 are different, that is, the components with a content of more than 50% in the alloy or mixed material are different.

[0124] By configuring the first wall 23 as an interconnected body portion 231 and a connecting portion 232, with the connecting portion 232 welded to the first electrode tab 242 and the body portion 231 connected to the side wall 211, an electrical connection is achieved between the electrode assembly 24 and the first wall 23. This allows for the input or output of electrical energy from the battery cell 20 through the first wall 23. On one hand, this reduces the number of electrode terminals and current collectors, lowering costs, reducing the space occupied within the battery cell 20, and increasing energy density. On the other hand, once the information acquisition device is electrically connected to the first wall 23, it can collect usage information from the battery cell 20. This facilitates the connection of the information acquisition device to the battery cell 20 and data acquisition, reducing the difficulty of data acquisition from the battery cell 20 and further lowering manufacturing costs. Furthermore, by setting the material of the connecting part 232 to be the same as that of the first tab 242, on the one hand, it is easier to weld the connecting part 232 and the first tab 242 together, which helps to reduce the assembly difficulty between the first wall 23 and the first tab 242 of the electrode assembly 24, thereby improving the assembly efficiency of the battery cell 20. On the other hand, it enables the first wall 23 and the first tab 242 to be welded together with the same material, thereby alleviating the phenomenon of different melting points and different coefficients of thermal expansion caused by welding the first wall 23 and the first tab 242 with different materials. This can reduce the phenomenon of welding cracks between the first wall 23 and the first tab 242, which helps to reduce the risk of leakage of the battery cell 20 and improve the reliability of the battery cell 20.

[0125] Referring to Figures 3, 4, 5, and 6, in some embodiments, the body portion 231 has an inner surface 2311 facing the electrode assembly 24, and the body portion 231 is provided with a receiving cavity 2312 extending to the inner surface 2311. The connecting portion 232 is at least partially received within the receiving cavity 2312.

[0126] The inner surface 2311 refers to the surface of the body portion 231 facing the electrode assembly 24. The receiving cavity 2312 is recessed from the inner surface 2311 of the body portion 231 in a direction away from the electrode assembly 24 and away from the first wall 23. In some embodiments, the receiving cavity 2312 is a receiving groove provided on the inner surface 2311. In other embodiments, the receiving cavity 2312 is a through hole penetrating the body portion 231 along the thickness direction of the first wall 23. Referring to Figures 3, 4, 5, and 6, the thickness direction of the first wall 23 is the X direction shown in the figures.

[0127] The connecting part 232 may be partially contained within the receiving cavity 2312 and partially protrude from the receiving cavity 2312, or the connecting part 232 may be completely contained within the receiving cavity 2312.

[0128] The receiving cavity 2312 is recessed from the inner surface 2311 of the body portion 231 toward the first wall 23 away from the electrode assembly 24. By at least partially accommodating the connecting portion 232 in the receiving cavity 2312, the occupation of the connecting portion 232 on the internal space of the battery cell 20 is further reduced, which is beneficial to improving the energy density of the battery cell 20.

[0129] Referring to Figures 3, 4, 5 and 6, in some embodiments, the receiving cavity 2312 is a receiving groove recessed from the inner surface 2311 in a direction away from the electrode assembly 24.

[0130] The receiving groove can be formed in various ways, such as stamping or cold heading. Taking the stamping method as an example, the receiving groove can be stamped on the inner surface 2311 of the body 231 along the direction of the electrode assembly 24 pointing to the first wall 23.

[0131] When the receiving cavity 2312 is a receiving tank provided in the body part 231, the electrolyte is less likely to leak from the receiving tank, which helps to reduce the risk of leakage of the battery cell 20 and improve the reliability of the battery cell 20.

[0132] Referring to Figures 4, 5, 7 and 8, in some embodiments, the body portion 231 also includes an outer surface opposite to the inner surface 2311, and the receiving cavity 2312 is a through hole penetrating the inner surface 2311 and the outer surface.

[0133] The outer surface is the surface of the body 231 that is opposite to the electrode assembly 24. The inner surface 2311 and the outer surface are disposed opposite each other along the thickness direction of the first wall 23.

[0134] The receiving cavity 2312 is a through hole, and the receiving cavity 2312 penetrates the inner surface 2311 and the outer surface of the body part 231 along the thickness direction of the first wall 23.

[0135] When the receiving cavity 2312 is a through hole that penetrates the inner surface 2311 and the outer surface, it is convenient to connect the connecting part 232 and the first electrode tab 242 by through welding, which helps to reduce the assembly difficulty between the first wall 23 and the first electrode tab 242 of the electrode assembly 24, thereby improving the assembly efficiency of the battery cell 20.

[0136] Please refer to Figures 4, 5, 7 and 8. In some embodiments, the connecting portion 232 is completely accommodated within the receiving cavity 2312.

[0137] By completely accommodating the connecting part 232 within the receiving cavity 2312, it is beneficial to reduce the space occupied by the connecting part 232 within the battery cell 20 and to improve the energy density of the battery cell 20.

[0138] Referring to Figures 4, 5, 7 and 8, in some embodiments, the surface of the connection portion 232 facing the electrode assembly 24 is flush with the inner surface 2311.

[0139] The surface of the connecting portion 232 facing the electrode assembly 24 is also the surface of the connecting portion 232 that is closest to the electrode assembly 24 along the thickness direction of the first wall 23. The surface of the connecting portion 232 facing the electrode assembly 24 is flush with the inner surface 2311, which can also be understood as the surface of the connecting portion 232 facing the electrode assembly 24 and the inner surface 2311 of the body portion 231 being located in the same plane.

[0140] By making the surface of the connecting part 232 facing the electrode assembly 24 flush with the inner surface 2311 of the body part 231, the space occupied by the connecting part 232 in the internal space of the battery cell 20 can be reduced, which is beneficial to improving the energy density of the battery cell 20. It also facilitates the welding of the connecting part 232 and the first tab 242, which is beneficial to improving the welding quality of the connecting part 232 and the first tab 242.

[0141] Please refer to Figures 4, 5, 7 and 8. In some embodiments, the outer peripheral surface 2321 of the connecting portion 232 is welded to the cavity wall surface of the receiving cavity 2312.

[0142] When the receiving cavity 2312 is a receiving groove, the cavity wall surface of the receiving cavity 2312 is the side surface of the receiving groove. When the receiving cavity 2312 is a through hole, the cavity wall surface of the receiving cavity 2312 is the hole wall surface of the through hole.

[0143] Referring to Figure 8, in the embodiment shown in Figure 8, the outer peripheral surface 2321 of the connecting portion 232 is welded to the cavity wall surface of the receiving cavity 2312 to form a second weld mark 26. Optionally, butt welding is used when welding the outer peripheral surface 2321 of the connecting portion 232 to the cavity wall surface of the receiving cavity 2312.

[0144] When the outer peripheral surface 2321 of the connecting part 232 is welded to the cavity wall of the receiving cavity 2312, a high welding quality can be achieved simply by matching the shape and size of the connecting part 232 with the shape and size of the receiving cavity 2312. Matching the shape and size of the connecting part 232 with the shape and size of the receiving cavity 2312 is relatively simple. Therefore, welding the outer peripheral surface 2321 of the connecting part 232 to the cavity wall of the receiving cavity 2312 is beneficial for improving welding quality. Furthermore, butt welding can be used when welding the outer peripheral surface 2321 of the connecting part 232 to the cavity wall of the receiving cavity 2312. Butt welding requires less heat, making the connecting part 232 and the body part 231 less prone to deformation during welding, thus further improving welding quality.

[0145] Please refer to Figure 9, which is a partial cross-sectional view of a battery cell 20 provided in some embodiments of this application. In some embodiments, the connecting portion 232 protrudes from the inner surface 2311 along the direction of the first wall 23 toward the electrode assembly 24.

[0146] Please refer to Figure 9. In the embodiment shown in Figure 9, a portion of the connecting portion 232 is accommodated within the receiving cavity 2312, while another portion of the connecting portion 232 is located outside the receiving cavity 2312.

[0147] Along the thickness direction of the first wall 23, the connecting portion 232 has a first surface facing the electrode assembly 24. When the connecting portion 232 protrudes from the inner surface 2311 along the direction of the first wall 23 toward the electrode assembly 24, the first surface is closer to the electrode assembly 24 than the inner surface 2311.

[0148] By making the connecting portion 232 protrude out of the receiving cavity 2312, it is convenient to weld the portion of the connecting portion 232 protruding out of the receiving cavity 2312 to the first electrode tab 242.

[0149] Referring to Figure 9, in some embodiments, the outer peripheral surface 2321 of the connecting portion 232 is welded to the inner surface 2311.

[0150] The main body 231 and the connecting part 232 can be connected by fillet welding to achieve welding between the outer peripheral surface 2321 of the connecting part 232 and the inner surface 2311 of the main body 231.

[0151] By welding the inner surface 2311 of the body part 231 to the outer peripheral surface 2321 of the connecting part 232, the body part 231 and the connecting part 232 are connected by fillet weld, thereby achieving a welded connection between the body part 231 and the connecting part 232. The first wall 23 with this structure can achieve a greater penetration depth at a lower welding power, which is beneficial to improving the welding effect between the connecting part 232 and the body part 231, thereby effectively improving the connection stability between the connecting part 232 and the body part 231.

[0152] Referring to Figure 9, in some embodiments, the connecting portion 232 is welded to the electrode tab to form a first solder mark 25. Along the thickness direction of the first wall 23, the connecting portion 232 and the electrode tab are stacked, and the electrode tab and the connecting portion 232 have an overlapping area. The first solder mark 25 is located in the overlapping area.

[0153] The first solder mark 25 is the solder mark formed by welding the connecting part 232 to the electrode tab.

[0154] The connecting portion 232 and the electrode tab are stacked along the thickness direction of the first wall 23, and the electrode tab and the connecting portion 232 have an overlapping area. The overlapping area refers to the region where the electrode tab and the connecting portion 232 overlap. In some embodiments, the projection of the electrode tab along the thickness direction of the first wall 23 is completely located within the connecting portion 232, in which case the entire electrode tab is located within the overlapping area. In other embodiments, the projection of the connecting portion 232 along the thickness direction of the first wall 23 is completely located within the electrode tab, in which case the entire connecting portion 232 is located within the overlapping area.

[0155] The first solder mark 25 is located in the overlapping area; in other words, the connector 232 and the tab are soldered in the overlapping area. Optionally, the connector 232 and the tab are through-welded.

[0156] The welding connection 232 and the first electrode tab 242 can be penetrated from the side of the first wall 23 away from the electrode assembly 24, which helps to reduce welding difficulty and improve welding quality.

[0157] In some embodiments, the first electrode 242 is a negative electrode.

[0158] The first electrode 242 is the negative electrode, and the material of the first electrode 242 can be copper. The material of the connecting part 232 can also be copper.

[0159] When the first tab 242 is the negative tab, the first wall 23 can serve as the negative electrode of the battery cell 20, so as to realize the input or output of electrical energy of the battery cell 20.

[0160] In some embodiments, the connecting portion 232 is made of copper, and the body portion 231 is made of iron.

[0161] Optionally, the body part 231 is made of steel, and the material of the body part 231 can be low carbon steel, medium carbon steel, or high carbon steel.

[0162] The connecting part 232 and the first electrode 242 are made of the same material, both of which are copper. The body part 231 is made of iron to give it higher strength, thereby helping it resist external forces and protect the internal components of the battery cell 20.

[0163] In some embodiments, the electrode terminals are insulated from the housing 2. The electrode assembly 24 also includes a second tab 243, which has the opposite polarity to the first tab 242, and is electrically connected to the electrode terminals.

[0164] The electrode terminals are components used for electrical connection with the second tab 243 of the electrode assembly 24 to input or output electrical energy from the battery cell 20. The electrode terminals are insulated from and mounted on the first wall 23, meaning that the electrode terminals are insulated from and isolated from the first wall 23.

[0165] The second tab 243 is either the negative or positive tab described above. In some embodiments, the second tab 243 is directly connected to the electrode terminal. In other embodiments, the battery cell 20 further includes a current collector, which is connected to the second tab 243 and the second electrode terminal to direct electrical energy from the electrode assembly 24 to the electrode terminal or receive electrical energy introduced from the electrode terminal.

[0166] The first tab 242 and the second tab 243 have opposite polarities. For example, when the first tab 242 is the positive tab, the second tab 243 is the negative tab. In this case, the first wall 23 serves as the positive electrode of the battery cell 20, and the electrode terminal serves as the negative electrode of the battery cell 20. When the first tab 242 is the negative tab, the second tab 243 is the positive tab. In this case, the first wall 23 serves as the negative electrode of the battery cell 20, and the electrode terminal serves as the positive electrode of the battery cell 20.

[0167] The first wall 23 can be electrically connected to the first tab 242, and the electrode terminal can be electrically connected to the second tab 243. The first wall 23 can serve as the positive or negative electrode of the battery cell 20, and the electrode terminal can serve as the negative or positive electrode of the battery cell 20, so as to output the electrical energy of the battery cell 20.

[0168] Please refer to Figures 3 and 4 again. The outer casing 2 includes a housing and an end cap 22. The housing has an opening, and the end cap 22 is connected to the housing and closes the opening. The first wall 23 is the end cap 22, and the body portion 231 is connected to the housing.

[0169] In an embodiment where the housing 21 has an opening at only one end, the end cap 22 serves as the first wall 23, and the side wall 211 is part of the housing 21. In this case, the body portion 231 can be welded to the side wall 211.

[0170] In an embodiment where openings are formed at both opposite ends of the housing 21, one of the two end caps 22 can serve as the first wall 23, the side wall 211 is the housing 21, and the body portion 231 can be welded to the housing.

[0171] When the end cap 22 is the first wall 23, the connecting part 232 is welded to the first pole lug 242, and the main body 231 is welded to the shell, which facilitates assembly and makes manufacturing simple and convenient.

[0172] In some embodiments, both the body portion 231 and the housing are made of steel.

[0173] For example, the steel material can be carbon steel, alloy steel, or stainless steel, etc.

[0174] In some embodiments, the steel material is carbon steel or stainless steel.

[0175] For example, carbon steel can be low-carbon steel, medium-carbon steel, or high-carbon steel.

[0176] By making the main body 231 and the casing of steel, the high strength of steel gives the casing 2 greater strength, which helps resist external forces and protects the internal components of the battery cell 20. Furthermore, the main body 231 and the casing are welded together using the same material. This mitigates the differences in melting points and coefficients of thermal expansion that can occur when welding the main body 231 and the casing using different materials. This reduces the likelihood of welding cracks between the main body 231 and the casing, thus lowering the risk of leakage from the battery cell 20 and improving its reliability.

[0177] Please refer to Figures 3 and 4. In some embodiments, the battery cell 20 is a cylindrical battery cell.

[0178] This application embodiment also provides a battery device 100, which includes the aforementioned battery cell 20.

[0179] This application embodiment also provides an electrical device, which includes the aforementioned battery cell 20, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0180] Please refer to Figures 3 to 9 for some embodiments of this application.

[0181] This application provides a battery cell 20, which includes a housing 2 and an electrode assembly 24. The housing 2 includes a side wall 211 and a first wall 23, with the side wall 211 surrounding the first wall 23. The first wall 23 includes a body portion 231 and a connecting portion 232 connected to each other. The body portion 231 is connected to the side wall 211, and the materials of the body portion 231 and the connecting portion 232 are different. The electrode assembly 24 is housed within the housing 2 and has a first tab 242. The connecting portion 232 is made of the same material as the first tab 242 and is welded to the first tab 242. By configuring the first wall 23 as an interconnected body portion 231 and connecting portion 232, with the connecting portion 232 welded to the first tab 242 and the body portion 231 connected to the side wall 211, an electrical connection is achieved between the electrode assembly 24 and the first wall 23, thereby enabling the input or output of electrical energy from the battery cell 20 through the first wall 23. On the one hand, it can reduce the number of electrode terminals and current collectors, thereby reducing costs, minimizing the space occupied inside the battery cell 20, and increasing energy density. On the other hand, once the information acquisition device is electrically connected to the first wall 23, it can collect usage information from the battery cell 20. This facilitates the connection of the information acquisition device to the battery cell 20 and the collection of data, reducing the difficulty of data collection from the battery cell 20 and further reducing manufacturing costs. Furthermore, by setting the material of the connecting part 232 to be the same as that of the first tab 242, on the one hand, it is easier to weld the connecting part 232 and the first tab 242 together, which helps to reduce the assembly difficulty between the first wall 23 and the first tab 242 of the electrode assembly 24, thereby improving the assembly efficiency of the battery cell 20. On the other hand, it enables the first wall 23 and the first tab 242 to be welded together with the same material, thereby alleviating the phenomenon of different melting points and different coefficients of thermal expansion caused by welding the first wall 23 and the first tab 242 with different materials. This can reduce the phenomenon of welding cracks between the first wall 23 and the first tab 242, which helps to reduce the risk of leakage of the battery cell 20 and improve the reliability of the battery cell 20.

[0182] The body portion 231 has an inner surface 2311 facing the electrode assembly 24, and a receiving cavity 2312 is provided in the body portion 2311, extending to the inner surface 2311. The connecting portion 232 is at least partially received within the receiving cavity 2312. The receiving cavity 2312 is recessed from the inner surface 2311 of the body portion 231 in a direction away from the electrode assembly 24 and towards the first wall 23. By at least partially receiving the connecting portion 232 within the receiving cavity 2312, the occupancy of the connecting portion 232 on the internal space of the battery cell 20 is further reduced, which is beneficial to improving the energy density of the battery cell 20.

[0183] In some embodiments, the surface of the connecting portion 232 facing the electrode assembly 24 is flush with the inner surface 2311, and the outer peripheral surface 2321 of the connecting portion 232 is welded to the cavity wall of the receiving cavity 2312. When the outer peripheral surface 2321 of the connecting portion 232 is welded to the cavity wall of the receiving cavity 2312, it is only necessary to match the shape and size of the connecting portion 232 with the shape and size of the receiving cavity 2312 to achieve a high welding quality. Matching the shape and size of the connecting portion 232 with the shape and size of the receiving cavity 2312 is relatively simple. Therefore, welding the outer peripheral surface 2321 of the connecting portion 232 to the cavity wall of the receiving cavity 2312 is beneficial to improving the welding quality. In addition, when welding the outer peripheral surface 2321 of the connecting portion 232 to the cavity wall of the receiving cavity 2312, butt welding can be used. Butt welding requires less heat, making the connecting portion 232 and the body portion 231 less prone to deformation during welding, thereby improving the welding quality.

[0184] In other embodiments, the connecting portion 232 protrudes from the inner surface 2311 along the direction of the first wall 23 toward the electrode assembly 24, and the outer peripheral surface 2321 of the connecting portion 232 is welded to the inner surface 2311. By welding the inner surface 2311 of the body portion 231 to the outer peripheral surface 2321 of the connecting portion 232, the body portion 231 and the connecting portion 232 are connected by fillet weld, thereby achieving a welded connection between the body portion 231 and the connecting portion 232. The first wall 23 with this structure can achieve a greater penetration depth at a lower welding power, which is beneficial to improving the welding effect between the connecting portion 232 and the body portion 231, thereby effectively improving the connection stability between the connecting portion 232 and the body portion 231.

[0185] The connecting portion 232 is made of copper, and the body portion 231 is made of iron. The body portion 231 and the side wall 211 are made of the same material. The connecting portion 232 and the first electrode tab 242 are made of the same material, and both the connecting portion 232 and the first electrode tab 242 are made of copper. The body portion 231 is made of iron to give it higher strength, thereby helping to resist external forces and protect the internal components of the battery cell 20. By making the body portion 231 and the side wall 211 the same material, it is easier to weld the body portion 231 and the side wall 211.

[0186] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, wherein, include: The outer casing includes side walls and a first wall, the side walls surrounding the first wall; An electrode assembly, housed within the housing, the electrode assembly having a first tab; The first wall includes a body portion and a connecting portion connected to each other. The body portion is connected to the side wall. The material of the body portion is different from that of the connecting portion. The material of the connecting portion is the same as that of the first electrode tab. The connecting portion is welded to the first electrode tab.

2. The battery cell according to claim 1, wherein, The body portion has an inner surface facing the electrode assembly, and the body portion is provided with a receiving cavity that extends to the inner surface, and the connecting portion is at least partially received within the receiving cavity.

3. The battery cell according to claim 2, wherein, The receiving cavity is a receiving groove that is recessed from the inner surface in a direction away from the electrode assembly.

4. The battery cell according to claim 2, wherein, The body portion also includes an outer surface opposite to the inner surface, and the receiving cavity is a through hole penetrating the inner surface and the outer surface.

5. The battery cell according to any one of claims 2-4, wherein, The connecting part is completely accommodated within the accommodating cavity.

6. The battery cell according to claim 5, wherein, The surface of the connecting portion facing the electrode assembly is flush with the inner surface.

7. The battery cell according to claim 6, wherein, The outer peripheral surface of the connecting part is welded to the cavity wall surface of the receiving cavity.

8. The battery cell according to any one of claims 2-4, wherein, The connecting portion protrudes from the inner surface along the direction of the first wall toward the electrode assembly.

9. The battery cell according to claim 8, wherein, The outer peripheral surface of the connecting part is welded to the inner surface.

10. The battery cell according to any one of claims 1-9, wherein, The connecting part is welded to the electrode tab to form a first solder mark. Along the thickness direction of the first wall, the connecting part and the electrode tab are stacked, and the electrode tab and the connecting part have an overlapping area. The first solder mark is located in the overlapping area.

11. The battery cell according to any one of claims 1-10, wherein, The first electrode is the negative electrode.

12. The battery cell according to any one of claims 1-11, wherein, The connecting part is made of copper, and the body part is made of iron.

13. The battery cell according to any one of claims 1-12, wherein, The battery cell includes electrode terminals, which are insulated from the housing. The electrode assembly further includes a second tab, which has the opposite polarity to the first tab, and is electrically connected to the electrode terminal.

14. The battery cell according to any one of claims 1-13, wherein, The outer casing includes: The shell has an opening; End cap, connected to the housing and closing the opening; The first wall is the end cap, and the main body is connected to the housing.

15. The battery cell according to claim 14, wherein, Both the main body and the housing are made of steel.

16. The battery cell according to any one of claims 1-15, wherein, The battery cell is a cylindrical battery cell.

17. A battery device, wherein, Includes the battery cell according to any one of claims 1-16.

18. An electrical appliance, wherein, Includes a battery cell according to any one of claims 1-16, the battery cell being used to provide electrical energy to the electrical equipment.

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