Battery monomer, battery and electric equipment

Abstract

The embodiment of the utility model provides a battery monomer, a battery and electric equipment. The battery monomer comprises a shell, an electrode terminal, an electrode assembly and an adapter. The shell comprises a first wall, and the electrode terminal is arranged on the first wall; the electrode assembly falls into the shell and is provided with a tab; the adapter is electrically connected with the electrode terminal and the tab; wherein the adapter is provided with a first surface deviating from the electrode terminal, the first surface comprises an embossed area and a first rough area, the embossed area and the first rough area have an overlapping area, the adapter is provided with a first connecting part connected with the electrode terminal, and the first connecting part is connected with the electrode terminal through a first welding mark; the first welding mark extends from the first surface to the electrode terminal, at least one part of the projection of the first welding mark falls into the projection of the overlapping area in the thickness direction of the first wall, and the thickness of the first connecting part is larger than or equal to 0.2 mm and smaller than or equal to 2 mm. According to the technical scheme, the reliability of the battery monomer can be improved.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor in their development.

[0003] During the manufacturing process of batteries, the reliability of batteries is an issue that cannot be ignored. Therefore, how to improve the reliability of batteries is a technical problem that needs to be solved urgently in battery technology. Utility Model Content

[0004] The present application provides a battery cell, a battery and an electrical device, which can improve the reliability of the battery cell.

[0005] This application is achieved through the following technical solutions:

[0006] In the first aspect, the embodiment of the present application provides a battery cell, which includes a shell, an electrode terminal, an electrode assembly and an adapter. The shell includes a first wall, and the electrode terminal is arranged on the first wall; the electrode assembly falls into the shell, and the electrode assembly has a tab; the adapter electrically connects the electrode terminal and the tab; wherein the adapter has a first surface away from the electrode terminal, the first surface includes an embossed area and a first rough area, the embossed area and the first rough area have an overlapping area, the adapter has a first connecting portion connected to the electrode terminal, the first connecting portion is connected to the electrode terminal through a first weld mark, the first weld mark extends from the first surface to the electrode terminal, along the thickness direction of the first wall, at least a part of the projection of the first weld mark falls into the projection of the overlapping area, and the thickness of the first connecting portion is greater than or equal to 0.2 mm and less than or equal to 2 mm.

[0007] According to the battery cell of the embodiment of the present application, while meeting the overcurrent requirement, the adapter has a thicker thickness, and the adapter is provided with an embossed area and a first rough area on the first surface away from the electrode terminal, and the embossed area and the first rough area have an overlapping area, and the overlapping area has a higher surface roughness, and the overlapping area has a higher laser absorption rate. When the adapter is laser welded to the electrode terminal, at least a part of the welding area of ​​the adapter is located in the overlapping area, and the overlapping area has a higher laser absorption rate. Without increasing the welding power, the interface temperature can be increased, and the welding effect between the adapter and the electrode terminal is improved. The adapter is firmly connected to the electrode terminal, and the battery cell has a higher reliability.

[0008] According to some embodiments of the present application, along the thickness direction of the first wall, the projection of the first welding mark entirely falls within the projection of the overlapping region.

[0009] In the above solution, since the projection of the first welding mark entirely falls within the projection of the overlapping region, when the adapter is laser welded to the electrode terminal, the welding area of the adapter is entirely located within the overlapping region, further reducing the reflection of the laser welding and improving the welding effect between the adapter and the electrode terminal, so as to facilitate a firm connection between the adapter and the electrode terminal.

[0010] According to some embodiments of the present application, the arithmetic mean roughness Ra of the first rough region is greater than or equal to 0.8 μm and less than or equal to 25 μm.

[0011] In the above solution, when the arithmetic mean roughness Ra of the first rough region satisfies the above relationship, on the one hand, it can reduce the welding reflection and improve the welding quality; on the other hand, the processing and manufacturing difficulty is relatively low.

[0012] According to some embodiments of the present application, the arithmetic mean roughness Ra of the first rough region is greater than or equal to 0.8 μm and less than or equal to 5 μm.

[0013] In the above solution, while meeting the requirement of reducing the welding reflection, the processing and manufacturing difficulty is reduced.

[0014] According to some embodiments of the present application, the embossed region includes a plurality of pits, and the depth of the pits is greater than or equal to 0.01 mm and less than or equal to 0.2 mm.

[0015] In the above solution, when the depth of the pits meets the above range, on the one hand, it can increase the surface roughness of the embossed region and reduce the reflection effect; on the other hand, it reduces the risk of damage to the adapter during welding.

[0016] According to some embodiments of the present application, the depth of the pits is greater than or equal to 0.03 mm and less than or equal to 0.15 mm.

[0017] In the above solution, when the depth of the pits meets the above range, while meeting the requirement of reducing the reflection effect, the risk of damage to the adapter during welding is reduced.

[0018] According to some embodiments of the present application, the three-dimensional shape of the pits is a prismatic shape, a cylindrical shape, a conical shape, or a hemispherical shape.

[0019] In the above solution, the processing and manufacturing difficulty of the pits is relatively low, which is convenient for processing and manufacturing.

[0020] According to some embodiments of the present application, the material of the adapter is aluminum. In the above solution, the material of the adapter is aluminum, which has high electrical conductivity and low cost. According to some embodiments of the present application, the thickness of the first connection portion is greater than or equal to 0.5 mm and less than or equal to 1.5 mm.

[0021] In the above solution, when the thickness of the first connection portion is 0.5 mm to 1.5 mm, the first connection portion has high strength, reducing the risk of welding damage to the first connection portion. At the same time, it is convenient for welding the first connection portion with the electrode terminal.

[0022] According to some embodiments of the present application, the material of the adapter is copper. In the above solution, the material of the adapter is copper, which has high electrical conductivity. According to some embodiments of the present application, the thickness of the first connection portion is greater than or equal to 0.4 mm and less than or equal to 1.5 mm.

[0023] In the above solution, when the thickness of the first connection portion is 0.4 mm to 1.5 mm, the first connection portion has high strength, reducing the risk of welding damage to the first connection portion. At the same time, it is convenient for welding the first connection portion with the electrode terminal.

[0024] According to some embodiments of the present application, the first surface further includes a second rough area, and the second rough area and the first rough area are arranged at intervals. The adapter and the tab are connected by a second welding mark, and the second welding mark extends from the side of the tab facing away from the adapter to the first surface. Along the thickness direction of the first wall, at least a part of the projection of the second welding mark falls into the projection of the second rough area.

[0025] In the above solution, when the tab and the adapter are ultrasonically welded, since the second rough area has a high surface roughness, at least a part of the tab can be welded to the second rough area, which can improve the welding quality of the adapter and the tab and improve the connection reliability between the adapter and the tab.

[0026] In a second aspect, an embodiment of the present application further provides a battery, which includes a battery cell provided according to any one of the above embodiments.

[0027] In a third aspect, an embodiment of the present application further provides an electrical device, which includes a battery cell or a battery provided according to any one of the above embodiments, and the battery cell or the battery is used to provide electrical energy.

[0028] The additional aspects and advantages of the present application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present application. Description of the Drawings

[0029] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following accompanying drawings only show some embodiments of the present application and should not be regarded as a limitation of the scope. For those of ordinary skill in the art, other related accompanying drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 Structural schematic diagram of a vehicle provided by some embodiments of the present application;

[0031] Figure 2 Exploded structural schematic diagram of a battery provided by some embodiments of the present application;

[0032] Figure 3 Exploded structural schematic diagram of a battery cell provided by some embodiments of the present application;

[0033] Figure 4 Schematic diagram of the state after a connecting piece is welded to an electrode terminal and a tab provided by some embodiments of the present application;

[0034] Figure 5 Schematic diagram of a welding mark on a connecting piece provided by some embodiments of the present application;

[0035] Figure 6 Schematic diagram of a welding mark on a connecting piece provided by some other embodiments of the present application;

[0036] Figure 7 Structural schematic diagram of a connecting piece provided by some embodiments of the present application.

[0037] Icon: 100 - battery; 10 - box body; 11 - first sub - box body; 12 - second sub - box body; 20 - battery cell; 21 - outer shell; 211 - housing; 212 - end cover; 213 - first wall; 22 - electrode assembly; 221 - tab; 221a - positive tab; 221b - negative tab; 23 - electrode terminal; 23a - positive electrode terminal; 23b - negative electrode terminal; 24 - connecting piece; 24a - positive connecting piece; 24b - negative connecting piece; 241 - first surface; 2411 - embossed area; 2412 - first rough area; 2413 - overlapping area; 2414 - pit; 2415 - second rough area; 242 - first connecting portion; 243 - second connecting portion; 25 - first welding mark; 26 - second welding mark; 200 - controller; 300 - motor; 1000 - vehicle; Y - thickness direction of the electrode assembly; Z - thickness direction of the first wall. Detailed implementation manners

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts fall within the scope of protection of this application.

[0039] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used in the description of this application in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description and claims of this application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and claims of this application or the above drawings are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0040] Reference to "embodiment" in this application means that a specific feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase does not necessarily refer to the same embodiment at every occurrence in the specification, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those of ordinary skill in the art will explicitly and implicitly understand that the embodiments described in this application can be combined with other embodiments.

[0041] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "coupled", and "attached" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] The term "and / or" in this application is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally represents an "or" relationship between the associated objects before and after.

[0043] The term "plurality" as used in this application refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0044] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0045] In some embodiments, the battery may be a battery pack. The battery pack includes a box body and battery cells, and the battery cells or battery modules are accommodated in the box body.

[0046] In some embodiments, the box body may be part of the chassis structure of a vehicle. For example, part of the box body may become at least part of the floor of the vehicle, or part of the box body may become at least part of the cross beam and longitudinal beam of the vehicle.

[0047] In some embodiments, the battery may be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0048] In the embodiments of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be activated by charging after discharging to continue use.

[0049] The battery cell may be, but is not limited to, 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-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc.

[0050] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, which can prevent the short circuit between the positive and negative electrodes and allow the active ions to pass through at the same time.

[0051] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet 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.

[0052] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0053] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, stainless steel with silver plating on the surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. can be used. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as 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.).

[0054] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials can also be used.

[0055] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0056] As an example, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, titanium, etc. may be used.

[0057] In some embodiments, the negative electrode current collector has two surfaces opposite to 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.

[0058] As an example, the negative electrode active material may be a negative electrode active material for batteries well-known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials can also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0059] In some embodiments, the separator is a separator membrane. The present application has no particular limitation on the type of the separator membrane, and any well-known porous structure separator membrane with good chemical stability and mechanical stability can be selected.

[0060] As an example, the main material of the separator membrane may be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator membrane may be a single-layer film or a multi-layer composite film, without particular limitation. When the separator membrane is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation. The separator may be a single component falling between the positive and negative electrodes, or may be attached to the surfaces of the positive and negative electrodes.

[0061] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and simultaneously functions to transport ions and isolate the positive and negative electrodes.

[0062] In some embodiments, the electrode assembly is a wound structure. The positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0063] In some embodiments, the electrode assembly has a laminated structure.

[0064] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), or a composite metal shell (such as a copper-aluminum composite shell), etc.

[0065] In some embodiments, the housing includes an end cap and a shell body. The shell body is provided with an opening, and the end cap closes the opening to form a sealed space for accommodating substances such as the electrode assembly and the electrolyte. The shell body may be provided with one or more openings. One or more end caps may also be provided.

[0066] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab of the electrode assembly. The electrode terminal can be indirectly connected to the tab through an adapter. The electrode terminal can be provided on the end cap or on the shell body.

[0067] In some embodiments, a pressure relief valve is provided on the housing. The pressure relief valve is used to release the internal pressure of the battery cell.

[0068] In some embodiments, the housing can be a sealed structure or a non-sealed structure. As an example, when the housing is a sealed structure, the housing can protect the electrode assembly and prevent, for example, electrolyte leakage. When the housing is a non-sealed structure, the housing can protect the electrode assembly, and a sealing bag can be further included between the housing and the electrode assembly. The sealing bag is used to encapsulate components such as the electrode assembly and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating part or an aluminum-plastic film.

[0069] As an example, the battery cell can be a square-shell battery cell, a blade-shaped battery cell, a multi-prismatic battery, and the multi-prismatic battery is, for example, a hexagonal-prismatic battery, etc.

[0070] The development of battery technology needs to consider multiple design factors simultaneously. For example, performance parameters such as energy density, discharge capacity, charge-discharge rate, etc. In addition, the reliability of the battery also needs to be considered.

[0071] There are many factors that affect the reliability of the battery, such as damage to the components inside the battery cell, damage to the outer shell caused by external forces on the battery cell, etc. In some embodiments, the battery cell includes an electrode terminal, an adapter and an electrode assembly, and the adapter electrically connects the electrode terminal and the pole ear of the electrode assembly. The adapter and the electrode terminal are usually laser welded to ensure that the adapter and the electrode terminal are firmly connected. In order to meet the overcurrent requirements, the thickness of the adapter is relatively thick. When the adapter and the electrode terminal are welded, the adapter and the electrode terminal are usually laser welded on the side of the adapter away from the electrode terminal. The thickness of the adapter is increased, and the heat dissipation effect of the adapter is increased, so that the temperature of the welding section of the adapter is not easy to increase. The welding quality of the adapter and the electrode terminal is poor, which easily leads to loose welding between the adapter and the electrode terminal, resulting in low reliability of the battery cell. If the laser welding power is increased, it will easily cause damage to the adapter, and the connection between the adapter and the electrode terminal will fail, which still makes the reliability of the battery cell low.

[0072] In view of this, the present application provides a battery cell, which includes a shell, an electrode terminal, an electrode assembly and an adapter. The shell includes a first wall, and the electrode terminal is arranged on the first wall; the electrode assembly falls into the shell, and the electrode assembly has a tab; the adapter electrically connects the electrode terminal and the tab; wherein the adapter has a first surface away from the electrode terminal, the first surface includes an embossed area and a first rough area, the embossed area and the first rough area have an overlapping area, the adapter has a first connecting portion connected to the electrode terminal, the first connecting portion is connected to the electrode terminal through a first weld mark, the first weld mark extends from the first surface to the electrode terminal, along the thickness direction of the first wall, at least a part of the projection of the first weld mark falls into the projection of the overlapping area, and the thickness of the first connecting portion is greater than or equal to 0.2 mm and less than or equal to 2 mm. The adapter is firmly welded to the electrode terminal, and the battery cell has high reliability.

[0073] In such a battery cell, under the condition of meeting the overcurrent requirement, the adapter has a relatively thick thickness, and the adapter is provided with an embossed area and a first rough area on the first surface away from the electrode terminal, and the embossed area and the first rough area have an overlapping area, so that the overlapping area has a higher surface roughness, and the overlapping area has a higher laser absorption rate. When the adapter is laser welded to the electrode terminal, at least a part of the welding area of ​​the adapter is located in the overlapping area. Since the surface roughness of the overlapping area is relatively high and has a high laser absorption rate, the interface temperature can be increased without increasing the welding power, and the welding effect between the adapter and the electrode terminal is improved. The adapter and the electrode terminal are firmly connected, and the reliability of the battery cell is improved.

[0074] The battery disclosed in the embodiment of the present application can be used in, but not limited to, electrical equipment such as vehicles, ships or aircraft. The battery disclosed in the present application can be used to form a power supply system of the electrical equipment.

[0075] Embodiments of the present application provide an electrical device using a battery as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, an electric bicycle, an electric motorcycle, an electric vehicle, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric aircraft toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, a spaceship, etc.

[0076] For the convenience of description, the following embodiments take a vehicle as an example of an electrical device in an embodiment of the present application for illustration.

[0077] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a vehicle provided by some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc. A battery 100 is disposed inside the vehicle 1000. The battery 100 may be disposed at the bottom, the head, or the tail of the vehicle 1000. The battery 100 may be used to supply power to the vehicle 1000. For example, the battery 100 may be used as an operating power source of the vehicle 1000 and be used for the circuit system of the vehicle 1000, such as the working power requirements for starting, navigating, and running the vehicle 1000.

[0078] The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300. For example, it is used for the working power requirements for starting, navigating, and driving the vehicle 1000.

[0079] In some embodiments of the present application, the battery 100 may not only be used as an operating power source of the vehicle 1000, but also be used as a driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0080] Please refer to Figure 2 , Figure 2Schematic exploded view of the structure of the battery provided by some embodiments of the present application. The battery 100 includes a box body 10 and battery cells 20, and the battery cells 20 are accommodated in the box body 10. Among them, the box body 10 is used to provide an accommodation space for the battery cells 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 may include a first sub-box body 11 and a second sub-box body 12. The first sub-box body 11 and the second sub-box body 12 cover each other, and the first sub-box body 11 and the second sub-box body 12 jointly define an accommodation space for accommodating the battery cells 20. The second sub-box body 12 may be a hollow structure with one end open, and the first sub-box body 11 may be a plate-like structure. The first sub-box body 11 covers the open side of the second sub-box body 12 so that the first sub-box body 11 and the second sub-box body 12 jointly define an accommodation space; the first sub-box body 11 and the second sub-box body 12 may also both be hollow structures with one side open, and the open side of the first sub-box body 11 covers the open side of the second sub-box body 12.

[0081] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection. A mixed connection means that there are both series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed connection together, and then the whole formed by the multiple battery cells 20 is accommodated in the box body 10; of course, the battery 100 can also be that multiple battery cells 20 are first connected in series, in parallel, or in a mixed connection to form a battery module form, and then multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole and are accommodated in the box body 10. The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component for realizing the electrical connection among the multiple battery cells 20.

[0082] Among them, the battery cell 20 can be a secondary battery or a primary battery; the battery cell 20 can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto.

[0083] Please refer to Figure 3 , Figure 3 Schematic exploded view of the structure of the battery cell provided by some embodiments of the present application. As Figure 3 shown, the battery cell 20 includes a housing 21, an electrode assembly 22, and electrode terminals 23. The housing 21 includes a shell 211 and an end cap 212. The shell 211 has an opening, and the end cap 212 closes the opening to isolate the internal environment of the battery cell 20 from the external environment.

[0084] The housing 211 is a component for cooperating with the end cap 212 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 22, the electrolyte, and other components. The housing 211 and the end cap 212 can be separate components. The housing 211 can be of various shapes and sizes. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 22. The material of the housing 211 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0085] The end cap 212 is a component that covers the opening of the housing 211 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 212 can be adapted to the shape of the housing 211 to cooperate with the housing 211. Optionally, the end cap 212 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 212 is not easily deformed when subjected to extrusion and collision, enabling the battery cell 20 to have higher structural strength and improved reliability. Functional components such as the electrode terminal 23 can be provided on the end cap 212. The electrode terminal 23 can be used to electrically connect with the electrode assembly 22 for outputting or inputting the electric energy of the battery cell 20. The material of the end cap 212 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not make special restrictions on this. In some embodiments, an insulating structure can also be provided on the inner side of the end cap 212, and the insulating structure can be used to isolate the electrical connection components in the housing 211 from the end cap 212 to reduce the risk of short circuit. Exemplarily, the insulating structure can be plastic, rubber, etc.

[0086] The electrode assembly 22 is a component in the battery cell 20 where an electrochemical reaction occurs. The housing 211 can contain one or more electrode assemblies 22. The electrode assembly 22 is mainly formed by winding or laminating a positive electrode plate and a negative electrode plate, and generally, a separator is provided between the positive electrode plate and the negative electrode plate to separate the positive electrode plate and the negative electrode plate to avoid internal short circuit between the positive electrode plate and the negative electrode plate. The parts of the positive electrode plate and the negative electrode plate with active substances constitute the main body part of the electrode assembly, and the parts of the positive electrode plate and the negative electrode plate without active substances respectively constitute the electrode tabs. The positive electrode tab and the negative electrode tab can both fall at one end of the main body part or fall at both ends of the main body part respectively.

[0087] Please refer to Figure 3 and further refer to Figure 4 and Figure 5 Figure 4 which is a schematic diagram of the state after the adapter is welded to the electrode terminal and the electrode tab provided by some embodiments of the present application, Figure 4 showing the first weld mark after the adapter is welded to the electrode terminal and the second weld mark after the electrode tab is welded to the adapter; Figure 5 ​Schematic diagram of welding marks on the adapter provided in some embodiments of the present application.

[0088] Some embodiments of the present application provide a battery cell 20, which includes a housing 21, an electrode terminal 23, an electrode assembly 22, and an adapter 24. The housing 21 includes a first wall 213, and the electrode terminal 23 is disposed on the first wall 213; the electrode assembly 22 is received within the housing 21, and the electrode assembly 22 has a tab 221; the adapter 24 electrically connects the electrode terminal 23 and the tab 221; wherein, the adapter 24 has a first surface 241 facing away from the electrode terminal 23, the first surface 241 includes an embossed area 2411 and a first rough area 2412, the embossed area 2411 and the first rough area 2412 have an overlapping area 2413, the adapter 24 has a first connecting portion 242 connected to the electrode terminal 23, the first connecting portion 242 and the electrode terminal 23 are connected by a first welding mark 25, the first welding mark 25 extends from the first surface 241 to the electrode terminal 23, along the thickness direction Z of the first wall, at least a part of the projection of the first welding mark 25 falls within the projection of the overlapping area 2413, the thickness of the first connecting portion 242 is greater than or equal to 0.2 mm and less than or equal to 2 mm.

[0089] The housing 21 may include a housing body 211 and an end cap 212, the housing body 211 has an opening, and the end cap 212 covers the opening. The first wall 213 may be the end cap 212 or a wall portion of the housing body 211.

[0090] The electrode terminal 23 may be insulatingly disposed on the first wall 213, or the electrode terminal 23 may be directly connected to the first wall 213.

[0091] In some embodiments, the first wall 213 may be provided with an electrode lead-out hole (not shown in the figure), the electrode lead-out hole may penetrate the first wall 213 along the thickness direction Z of the first wall, the electrode terminal 23 covers the electrode lead-out hole, and the adapter 24 is connected to the electrode terminal 23 through the electrode lead-out hole. For example, a part of the adapter 24 may extend into the electrode lead-out hole and be connected to the electrode terminal 23, or a part of the electrode terminal 23 may extend into the electrode lead-out hole and be connected to the adapter 24, or a part of the adapter 24 and a part of the electrode terminal 23 may both extend into the electrode lead-out hole and be connected.

[0092] In some embodiments, the electrode assembly 22 may be a wound structure or a stacked structure. The electrode assembly 22 may be flat, and the thickness direction Y of the electrode assembly may be perpendicular to the thickness direction Z of the first wall. When the electrode assembly 22 is a wound structure, the electrode assembly 22 includes a straight section and a bent section, and the thickness direction Y of the electrode assembly is parallel to the lamination direction of the electrode plates in the straight section.

[0093] In some embodiments, the battery cell 20 is a square battery cell.

[0094] Please refer to Figure 3 ,In some embodiments, the electrode terminal 23 includes a positive electrode terminal 23a and a negative electrode terminal 23b, the adapter 24 includes a positive adapter 24a and a negative adapter 24b, the tab 221 includes a positive tab 221a and a negative tab 221b, the positive electrode terminal 23a is electrically connected to the positive tab 221a through the positive adapter 24a, and the negative electrode terminal 23b is electrically connected to the negative tab 221b through the negative adapter 24b.

[0095] In some embodiments, the electrode terminal 23 and the tab 221 are respectively welded to the adapter 24 so that the electrode terminal 23 and the tab 221 are firmly connected to the adapter 24. Please refer to Figure 4 and Figure 5 ,The electrode terminal 23 is welded to the adapter 24 to form a first weld mark 25, and the tab 221 is welded to the adapter 24 to form a second weld mark 26.

[0096] The first surface 241 is the surface of the adapter 24 facing away from the electrode terminal 23, or the surface of the adapter 24 facing the electrode assembly 22 is the first surface 241. The surface of the first connecting portion 242 facing the electrode assembly 22 is the first surface 241.

[0097] The embossed area 2411 refers to the area formed on the first surface 241 after stamping by a pressing head. The surface of the pressing head is provided with protrusions. After the pressing head is overlaid with the adapter 24, pits are formed on the first surface 241 to form the embossed area 2411.

[0098] The first rough area 2412 refers to the non-smooth area of the first surface 241, and the first rough area 2412 has a relatively high surface roughness.

[0099] In some embodiments, the first rough area 2412 can be formed on the first surface 241 by means of electric discharge machining, etching, laser engraving or sandblasting.

[0100] The overlapping area 2413 refers to the area of the first surface 241 where the embossed area 2411 and the first rough area 2412 are provided. The overlapping area 2413 is rougher than other areas of the first surface 241. The overlapping area 2413 has a relatively high surface roughness and is less likely to reflect light. When the adapter 24 and the electrode terminal 23 are laser welded, the overlapping area 2413 has a poor light reflection effect, which can facilitate laser welding and improve the welding quality of the adapter 24 and the electrode terminal 23.

[0101] The first weld mark 25 refers to the structure formed by welding the first connecting portion 242 and the electrode terminal 23. For example, the adapter 24 and the electrode terminal 23 are laser welded to form the first weld mark 25.

[0102] In some embodiments, on a side of the adapter 24 facing away from the electrode terminal 23, laser welding is performed on the overlapping region 2413 of the first connection portion 242 and the electrode terminal 23 to form a first weld mark 25.

[0103] That "the first weld mark 25 extends from the first surface 241 to the electrode terminal 23" means that, from a side of the adapter 24 facing away from the electrode terminal 23, the adapter 24 and the electrode terminal 23 are welded to fix the adapter 24 to the electrode terminal 23.

[0104] That "at least a part of the projection of the first weld mark 25 falls within the projection of the overlapping region 2413 along the thickness direction Z of the first wall" means that, when observed along the thickness direction Z of the first wall, a part of the first weld mark 25 overlaps with the overlapping region 2413, or the whole of the first weld mark 25 overlaps with the overlapping region 2413.

[0105] The thickness of the first connection portion 242 may be the maximum thickness of the first connection portion 242. For example, if the first surface 241 of the first connection portion 242 is uneven, the thickness of the first connection portion 242 may be the thickness at the thickest part of the first connection portion 242. The thickness direction of the first connection portion 242 may be parallel to the thickness direction of the adapter 24, and the thickness direction of the first connection portion 242 may be parallel to the thickness direction Z of the first wall.

[0106] In some embodiments, the thickness of the first connection portion 242 may be any one of 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm or within the range between any two of them.

[0107] When the thickness of the first connection portion 242 meets the above range (greater than or equal to 0.2 mm and less than or equal to 2 mm), on the one hand, the first connection portion 242 has relatively high strength and is firmly welded to the electrode terminal 23; on the other hand, the welding difficulty between the first connection portion 242 and the electrode terminal 23 is relatively low.

[0108] According to the battery cell 20 of the embodiment of the present application, in the case of meeting the overcurrent requirement, the adapter 24 has a relatively thick thickness. The adapter 24 is provided with an embossed area 2411 and a first rough area 2412 on the first surface 241 facing away from the electrode terminal 23, and the embossed area 2411 and the first rough area 2412 have an overlapping area 2413. The overlapping area 2413 has a relatively high surface roughness and a relatively high laser absorption rate. When the adapter 24 is laser welded to the electrode terminal 23, at least a part of the welding area of the adapter 24 is located in the overlapping area 2413. The overlapping area 2413 has a relatively high laser absorption rate, which can increase the interface temperature and improve the welding effect between the adapter 24 and the electrode terminal 23 without increasing the welding power. The adapter 24 and the electrode terminal 23 are firmly connected, and the battery cell 20 has relatively high reliability.

[0109] Figure 4 and Figure 5 are all schematic projection diagrams along the thickness direction of the first wall. Please refer to Figure 4 and Figure 5 , according to some embodiments of the present application, along the thickness direction Z of the first wall, the projection of the first weld mark 25 entirely falls within the projection of the overlapping area 2413.

[0110] The overlapping area 2413 has a relatively large area. When the adapter 24 is laser welded to the electrode terminal 23, the laser beam acts on the overlapping area 2413, so that the projection of the first weld mark 25 entirely falls within the projection of the overlapping area 2413.

[0111] In the above solution, the projection of the first weld mark 25 entirely falls within the projection of the overlapping area 2413. When the adapter 24 is laser welded to the electrode terminal 23, the welding area of the adapter 24 is entirely located in the overlapping area 2413, further reducing the reflection of laser welding and improving the welding effect between the adapter 24 and the electrode terminal 23, so as to facilitate the firm connection between the adapter 24 and the electrode terminal 23.

[0112] According to some embodiments of the present application, the arithmetic mean roughness Ra of the first rough area 2412 is greater than or equal to 0.8 μm and less than or equal to 25 μm.

[0113] For example, the arithmetic mean roughness Ra of the first rough area 2412 can be any one of 0.8 μm, 1.6 μm, 2.4 μm, 3.2 μm, 4 μm, 5 μm, 6.3 μm, 12.5 μm, 16 μm, 20 μm, 25 μm or the range between any two of them.

[0114] The arithmetic mean roughness Ra of the first rough area 2412 can be obtained by a roughness tester, which is not described in detail in the present application.

[0115] In the above solution, the arithmetic mean roughness Ra of the first rough area 2412 satisfies the above relationship, which can reduce welding reflection and improve welding quality on the one hand, and has a relatively low manufacturing difficulty on the other hand.

[0116] According to some embodiments of the present application, the arithmetic mean roughness Ra of the first rough area 2412 is greater than or equal to 0.8 μm and less than or equal to 5 μm.

[0117] In the above solution, when the arithmetic mean roughness Ra of the first rough area 2412 satisfies the above relationship (greater than or equal to 0.8 μm and less than or equal to 5 μm), the manufacturing difficulty is reduced while reducing welding reflection.

[0118] According to some embodiments of the present application, the embossed area 2411 includes a plurality of pits 2414, and the depth of the pits 2414 is greater than or equal to 0.01 mm and less than or equal to 0.2 mm.

[0119] The pits 2414 are formed by the first surface 241 being recessed along the thickness direction of the adapter 24. For example, the pits 2414 can be formed by stamping the adapter 24.

[0120] The depth direction of the pits 2414 can be parallel to the thickness direction of the adapter 24.

[0121] Optionally, the depth of the pits 2414 can be any one or the range between any two of 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm.

[0122] In the above solution, when the depth of the pits 2414 satisfies the above range, on the one hand, it can increase the surface roughness of the embossed area 2411 and reduce the reflection effect, and on the other hand, it can reduce the risk of welding damage to the adapter 24.

[0123] According to some embodiments of the present application, the depth of the pits 2414 is greater than or equal to 0.03 mm and less than or equal to 0.15 mm.

[0124] In the above solution, when the depth of the pits 2414 satisfies the above range, the risk of welding damage to the adapter 24 is reduced while reducing the reflection effect.

[0125] According to some embodiments of the present application, the three-dimensional shape of the pits 2414 is a rhombic prism, a cylinder, a cone or a hemisphere.

[0126] The three-dimensional shape of the pit 2414 can be the three-dimensional shape of the protrusion on the indenter. For example, it can be obtained by a laser scanner, or by filling the pit 2414 with soft lead and then taking out the soft lead, and the shape of the soft lead is the three-dimensional shape of the pit 2414.

[0127] The pit 2414 in the shape of a prism, a cylinder, a cone or a hemisphere can increase the surface roughness of the embossing area 2411.

[0128] In the above solution, the processing and manufacturing of the pit 2414 are of low difficulty and are convenient for processing and manufacturing.

[0129] Please refer to Figure 5 and Figure 6 , according to some embodiments of the present application, the material of the adapter 24 is aluminum.

[0130] The material of the adapter 24 is aluminum. The adapter 24 has good electrical conductivity, which is convenient for the transmission of current, and has a low cost.

[0131] According to some embodiments of the present application, the thickness of the first connecting portion 242 is greater than or equal to 0.5 mm and less than or equal to 1.5 mm.

[0132] In the above solution, the material of the adapter 24 is aluminum. When the thickness of the first connecting portion 242 is 0.5 mm to 1.5 mm, the first connecting portion 242 has high strength, reducing the risk of welding damage to the first connecting portion 242. At the same time, it is convenient for the welding of the first connecting portion 242 and the electrode terminal 23.

[0133] Optionally, the thickness of the first connecting portion 242 is greater than or equal to 0.6 mm or less than or equal to 1.2 mm.

[0134] According to some embodiments of the present application, the material of the adapter 24 is copper.

[0135] The material of the adapter 24 is copper. The adapter 24 has good electrical conductivity, which is convenient for the transmission of current.

[0136] According to some embodiments of the present application, the thickness of the first connecting portion 242 is greater than or equal to 0.4 mm and less than or equal to 1.5 mm.

[0137] In the above solution, the material of the adapter 24 is copper. When the thickness of the first connecting portion 242 is 0.4 mm to 1.5 mm, the first connecting portion 242 has high strength, reducing the risk of welding damage to the first connecting portion 242. At the same time, it is convenient for the welding of the first connecting portion 242 and the electrode terminal 23.

[0138] Optionally, the thickness of the first connecting portion 242 is greater than or equal to 0.6 mm and less than or equal to 1 mm.

[0139] Please refer to Figure 4 and further refer to Figure 6 and Figure 7 , Figure 6 which is a schematic diagram of a welding mark on a transition piece provided in some other embodiments of the present application, Figure 7 and which is a schematic structural diagram of a transition piece provided in some embodiments of the present application. According to some embodiments of the present application, the first surface 241 further includes a second rough area 2415. The second rough area 2415 and the first rough area 2412 are arranged at intervals. The transition piece 24 and the tab 221 are connected by a second welding mark 26. The second welding mark 26 extends from a side of the tab 221 facing away from the transition piece 24 to the first surface 241. Along the thickness direction Z of the first wall, at least a part of the projection of the second welding mark 26 falls into the projection of the second rough area 2415.

[0140] The second rough area 2415 and the first rough area 2412 are arranged at intervals. The second rough area 2415 is arranged corresponding to the tab 221, and the first rough area 2412 is arranged corresponding to the electrode terminal 23.

[0141] The second welding mark 26 is a structure formed by welding the transition piece 24 and the tab 221. On a side of the tab 221 facing away from the transition piece 24, the tab 221 and the transition piece 24 are welded to form the second welding mark 26. The second welding mark 26 extends from a side of the tab 221 facing away from the transition piece 24 to the first surface 241 to fix the tab 221 to the transition piece 24.

[0142] In some embodiments, the tab 221 and the transition piece 24 are ultrasonically welded, which has simple operation and low processing difficulty.

[0143] "Along the thickness direction Z of the first wall, at least a part of the projection of the second welding mark 26 falls into the projection of the second rough area 2415" means that when observing along the thickness direction Z of the first wall, a part of the second welding mark 26 overlaps with the second rough area 2415, or all of the second welding mark 26 overlaps with the second rough area 2415. For example, a part of the welding area of the transition piece 24 and the tab 221 is located in the second rough area 2415.

[0144] In the above solution, when the tab 221 and the transition piece 24 are ultrasonically welded, since the second rough area 2415 has a relatively high surface roughness, at least a part of the tab 221 can be welded to the second rough area 2415, which can improve the welding quality of the transition piece 24 and the tab 221 and improve the connection reliability between the transition piece 24 and the tab 221.

[0145] According to some embodiments of the present application, along the thickness direction Z of the first wall, the entire projection of the second welding mark 26 falls within the projection of the second rough area 2415.

[0146] For example, when the tab 221 is welded to the adapter 24, the welding area is located within the second rough area 2415, facilitating the ultrasonic welding of the tab 221 and the adapter 24 and improving the welding quality of the tab 221 and the adapter 24.

[0147] In some embodiments, the first rough area 2412 and the second rough area 2415 may be areas obtained by the same rough treatment method for the first surface 241.

[0148] Please refer to Figures 4 to 7 , according to some embodiments of the present application, the adapter 24 further includes a second connecting portion 243 connected to the tab 221. The tab 221 is ultrasonically welded to the second connecting portion 243, and the thickness of the second connecting portion 243 may be greater than the thickness of the first connecting portion 242.

[0149] According to some embodiments of the present application, the number of electrode assemblies 22 is two, and the tabs 221 of the two electrode assemblies 22 are respectively connected to the adapter 24 and form two second welding marks 26.

[0150] In some embodiments, the entire first surface 241 may be subjected to rough treatment to form a first rough area 2412 in the corresponding area between the first surface 241 and the electrode terminal 23, facilitating processing and manufacturing.

[0151] According to some embodiments of the present application, the embodiments of the present application further provide a battery 100, which includes a battery cell 20 provided according to any one of the above embodiments.

[0152] According to some embodiments of the present application, the embodiments of the present application further provide an electrical device, which includes the battery cell 20 or the battery 100 provided according to any one of the above embodiments, and the battery cell 20 or the battery 100 is used to provide electrical energy.

[0153] The electrical device is any device or system that applies the battery cell 20 or the battery 100 as described above.

[0154] The embodiments of the present application provide a manufacturing method for a battery cell 20, and the manufacturing method includes:

[0155] S100, providing an adapter 24, the adapter 24 having an embossed area 2411 and a first rough area 2412, and the embossed area 2411 and the first rough area 2412 having an overlapping area 2413;

[0156] S200, providing an electrode terminal 23;

[0157] In S300, the adapter 24 and the electrode terminal 23 are welded to form a first weld mark 25. The first weld mark 25 extends from the side of the adapter 24 facing away from the electrode terminal 23 to the electrode terminal 23. Along the thickness direction Z of the first wall, at least a part of the projection of the first weld mark 25 falls within the projection of the overlapping region 2413.

[0158] Among them, the order of the steps "S100, provide an adapter 24, the adapter 24 has an embossed area 2411 and a first rough area 2412, and the embossed area 2411 and the first rough area 2412 have an overlapping area 2413" and "S200, provide an electrode terminal 23" is not unique. The steps "S100, provide an adapter 24, the adapter 24 has an embossed area 2411 and a first rough area 2412, and the embossed area 2411 and the first rough area 2412 have an overlapping area 2413" and "S200, provide an electrode terminal 23" can be executed in sequence, or the steps "S200, provide an electrode terminal 23" and "S100, provide an adapter 24, the adapter 24 has an embossed area 2411 and a first rough area 2412, and the embossed area 2411 and the first rough area 2412 have an overlapping area 2413" can also be executed in sequence.

[0159] In the step "S300, the adapter 24 and the electrode terminal 23 are welded to form a first weld mark 25. The first weld mark 25 extends from the side of the adapter 24 facing away from the electrode terminal 23 to the electrode terminal 23. Along the thickness direction Z of the first wall, at least a part of the projection of the first weld mark 25 falls within the projection of the overlapping region 2413", on the side of the adapter 24 facing away from the electrode terminal 23, the adapter 24 and the electrode terminal 23 are laser welded to form a first weld mark 25. Among them, at least a part of the welding area of the adapter 24 is located in the overlapping region 2413. The first weld mark 25 extends from the side of the adapter 24 facing away from the electrode terminal 23 to the electrode terminal 23. Along the thickness direction Z of the first wall, at least a part of the projection of the first weld mark 25 falls within the projection of the overlapping region 2413.

[0160] According to some embodiments of the present application, please refer to Figures 3 to 7 , an embodiment of the present application provides a battery cell 20, which includes a housing 21, an electrode terminal 23, an electrode assembly 22 and an adapter 24.

[0161] The housing 21 is in the shape of a cuboid. The housing 21 includes a housing body 211 and an end cover 212. The housing body 211 has an opening, and the end cover 212 covers the opening.

[0162] The electrode terminal 23 is disposed on the end cover 212.

[0163] The electrode assembly 22 is disposed in the housing body 211. The electrode assembly 22 has a tab 221.

[0164] The adapter 24 has a first surface 241 facing away from the electrode terminal 23. The first surface 241 includes an embossed area 2411 and a first rough area 2412. The embossed area 2411 and the first rough area 2412 have an overlapping area 2413. The adapter 24 has a first connecting portion 242 connected to the electrode terminal 23. The first connecting portion 242 and the electrode terminal 23 are laser welded to form a first welding mark 25. The first welding mark 25 extends from the first surface 241 to the electrode terminal 23. Along the thickness direction Z of the first wall, the entire projection of the first welding mark 25 falls within the projection of the overlapping area 2413. The thickness of the first connecting portion 242 is greater than or equal to 0.2 mm and less than or equal to 2 mm.

[0165] For the battery cell 20 according to the embodiment of the present application, when the overcurrent requirement is met, the first connecting portion 242 has a relatively thick thickness. The overlapping area 2413 is used to weld the adapter 24 and the electrode terminal 23. The overlapping area 2413 has a relatively high roughness and a relatively high laser absorption rate. When the adapter 24 and the electrode terminal 23 are laser welded, at least a part of the welding area of the adapter 24 is located in the overlapping area 2413. The overlapping area 2413 has a relatively high laser absorption rate. Without increasing the welding power, it can increase the interface temperature, improve the welding quality of the laser welding between the adapter 24 and the electrode terminal 23, improve the connection reliability between the adapter 24 and the electrode terminal 23, and make the battery cell 20 have relatively high reliability.

[0166] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it and components therein can be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. 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: a housing including a first wall; an electrode terminal, disposed on the first wall; An electrode assembly falls into the housing, wherein the electrode assembly has a tab; A transition piece, electrically connecting the electrode terminal and the tab; The adapter has a first surface facing away from the electrode terminal, the first surface includes an embossed area and a first rough area, the embossed area and the first rough area have an overlapping area, the adapter has a first connecting portion connected to the electrode terminal, the first connecting portion is connected to the electrode terminal through a first weld mark, the first weld mark extends from the first surface to the electrode terminal, along the thickness direction of the first wall, at least a portion of the projection of the first weld mark falls into the projection of the overlapping area, and the thickness of the first connecting portion is greater than or equal to 0.2 mm and less than or equal to 2 mm.

2. The battery cell according to claim 1, characterized in that: Along the thickness direction of the first wall, the projections of the first weld marks all fall into the projection of the overlapping area.

3. The battery cell according to claim 1, characterized in that: An arithmetic mean value Ra of roughness of the first rough area is greater than or equal to 0.8 μm and less than or equal to 25 μm.

4. The battery cell according to claim 3, characterized in that: An arithmetic mean value Ra of roughness of the first rough area is greater than or equal to 0.8 μm and less than or equal to 5 μm.

5. The battery cell according to claim 1, characterized in that: The embossed area includes a plurality of pits, and the depth of the pits is greater than or equal to 0.01 mm and less than or equal to 0.2 mm.

6. The battery cell according to claim 5, characterized in that: The depth of the pit is greater than or equal to 0.03 mm and less than or equal to 0.15 mm.

7. The battery cell according to claim 5, characterized in that: The three-dimensional shape of the pit is rhombus, cylinder, cone or hemispherical.

8. The battery cell according to claim 1, characterized in that: The material of the adapter is aluminum.

9. The battery cell according to claim 8, characterized in that: The thickness of the first connecting portion is greater than or equal to 0.5 mm and less than or equal to 1.5 mm.

10. The battery cell according to claim 1, characterized in that: The material of the adapter is copper.

11. The battery cell according to claim 10, characterized in that: The thickness of the first connecting portion is greater than or equal to 0.4 mm and less than or equal to 1.5 mm.

12. The battery cell according to claim 1, characterized in that: The first surface also includes a second rough area, the second rough area and the first rough area are arranged at intervals, the adapter is connected to the pole ear through a second weld mark, the second weld mark extends from the side of the pole ear away from the adapter to the first surface, along the thickness direction of the first wall, at least a part of the projection of the second weld mark falls into the projection of the second rough area.

13. A battery, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 12.

14. An electrical device, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 12 or the battery according to claim 13, wherein the battery cell or the battery is used to provide electrical energy.

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