Battery monomer, battery and electric device

Abstract

The invention provides a battery monomer, a battery and a power utilization device, the battery monomer comprises an electrode assembly, a shell and a coating, the electrode assembly is accommodated in the shell, the shell is provided with a welding part, the welding part is electrically connected to a tab of the battery monomer, and the coating is arranged on the outer side of the shell and covers the welding part. The welding part is covered with the coating, so that the welding part is protected, the possibility of corrosion of the welding part is reduced, and the reliability of the single battery is improved.

Description

Battery cells, batteries and electrical devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202323248943.X, filed on November 29, 2023, entitled “Battery Cell, Battery and Electrical Device,” the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] Batteries have the advantages of high specific energy and high power density. They are widely used in electronic devices and transportation vehicles, such as mobile phones, laptops, electric vehicles, electric airplanes, electric ships, and electric tools.

[0005] As the application scope of batteries continues to expand, people's requirements for battery reliability are also getting higher and higher. How to improve battery reliability has always been the focus of those skilled in the art.

[0006] Summary of the Invention

[0007] In view of the above problems, the present application provides a battery cell, a battery and an electrical device, wherein the battery cell has good reliability.

[0008] In a first aspect, some embodiments of the present application provide a battery cell, which includes an electrode assembly, a shell and a coating, wherein the electrode assembly includes a tab; the electrode assembly is accommodated in the shell, the shell is provided with a welding portion, and the welding portion is electrically connected to the tab; the coating is arranged on the outside of the shell and covers the welding portion.

[0009] In the above structure, by covering the welding portion with the coating, the welding portion is protected, which reduces the possibility of rusting of the welding portion and helps to improve the reliability of the battery cell.

[0010] According to some embodiments of the present application, the battery cell housing includes a wall portion, a recessed portion is formed on the outer side of the wall portion, and a welded portion is formed on the bottom wall of the recessed portion; at least a portion of the coating is accommodated in the recessed portion. This structure allows the molten zone formed by the welding of the tab and the welded portion to be located on the bottom wall of the recessed portion, reducing the possibility of the molten zone protruding from the wall portion and thus reducing the risk of the molten zone being impacted.

[0011] According to the battery cells provided in some embodiments of the present application, the coating is entirely contained in the recess, so that the melting zones of the coating and the welding portion are both located in the recess, which is beneficial to reducing the possibility of the melting zones and the coating being bumped, which is beneficial not only to extending the life of the coating, but also to improving the reliability of the connection between the tab and the welding portion.

[0012] According to the battery cell provided in some embodiments of the present application, the outer surface of the coating is flush with the outer surface of the wall, making the outer surface of the wall smooth, which is beneficial to improving the smoothness of the appearance of the battery cell.

[0013] According to the battery cells provided in some embodiments of the present application, the thickness of the coating is H1, 5μm≤H1≤400μm, which not only ensures that the coating has a good protective effect but also avoids waste of coating due to excessive thickness.

[0014] According to the battery cells provided in some embodiments of the present application, 10 μm ≤ H1 ≤ 200 μm, so that the coating has a good protective effect and is unlikely to cause coating waste.

[0015] According to the battery cell provided in some embodiments of the present application, the shell also includes a plating layer arranged on the outside of the wall, and the plating layer surrounds the welding portion; the coating is connected to the plating layer, and the plating layer can protect the wall and reduce rust on the wall.

[0016] According to the battery cells provided in some embodiments of the present application, the projection of the welding portion is located within the range of the coating along the thickness direction of the wall portion, so that the welding portion can be more comprehensively covered and protected by the coating, which is beneficial to reducing the possibility of rust on the welding portion.

[0017] According to the battery cell provided in some embodiments of the present application, the wall portion is a carbon steel structure, and the plating layer is a nickel plating layer, so that the plating layer can protect the wall portion and reduce rust on the wall portion.

[0018] According to the battery cells provided in some embodiments of the present application, the thickness of the coating is H2, 0.05 μm≤H2≤10 μm, so that the coating has a good protective effect without causing waste or increasing costs due to excessive thickness.

[0019] According to the battery cells provided in some embodiments of the present application, 0.1 μm≤H2≤5 μm, so that the coating has a good protective effect and is not likely to cause waste or increase costs.

[0020] According to the battery cell provided in some embodiments of the present application, the coating layer includes a coating material, and the coating material includes polyacrylate, polyurethane or epoxy resin, so that the coating material can be formed on the outer surface of the welding portion.

[0021] According to the battery cells provided in some embodiments of the present application, the viscosity of the coating material ranges from 0.5 cps to 2000 cps, so that the viscosity of the coating material can meet the requirements of coating processes such as spraying, printing, and dispensing, making it easier to apply the coating material to the welding part.

[0022] According to the battery cell provided in some embodiments of the present application, the viscosity of the coating material ranges from 1 cps to 1000 cps, so that the coating material can be conveniently applied to the welding portion.

[0023] According to the battery cells provided in some embodiments of the present application, the adhesion between the coating and the welding part ranges from level 0 to level 1, so that the adhesion between the coating and the welding part is relatively large, the coating can be firmly attached to the welding part and is not prone to falling off, which is beneficial to extending the life of the coating.

[0024] According to the battery cells provided in some embodiments of the present application, the hardness of the coating is lower than that of the welding portion, so that when the battery cell is bumped, the coating is more easily damaged than the welding portion to cushion the bump, thereby helping to reduce the possibility of damage to the welding portion.

[0025] According to the battery cells provided in some embodiments of the present application, the distance L between the edge of the coating and the edge of the weld is greater than 0.1 mm, so that the coating covers the weld more completely, which is beneficial for the coating to better protect the weld and reduce the possibility of rust on the weld.

[0026] In a second aspect, some embodiments of the present application further provide a battery comprising a battery cell provided by any of the above technical solutions.

[0027] In a second aspect, some embodiments of the present application further provide an electrical device, which includes the battery provided by the aforementioned technical solution, and the battery is used to provide electrical energy.

[0028] The technical solutions provided by the embodiments of the present disclosure bring at least the following beneficial effects:

[0029] Some embodiments of the present application provide a battery cell comprising an electrode assembly, a housing, and a coating. The electrode assembly is housed within the housing, the housing having a welding portion electrically connected to a tab of the battery cell, and the coating is disposed on the exterior of the housing and covers the welding portion. By covering the welding portion with the coating, the welding portion is protected, the likelihood of rusting the welding portion is reduced, and the reliability of the battery cell is improved.

[0030] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0032] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0033] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0034] FIG3 is a cross-sectional view of a battery cell provided in some embodiments of the present application;

[0035] FIG4 is an enlarged view of point A in FIG3 ;

[0036] FIG5 is a cross-sectional view of a battery cell provided in some other embodiments of the present application;

[0037] Figure 6 is an enlarged view of point B in Figure 5;

[0038] FIG7 is a schematic structural diagram of a battery cell provided in some embodiments of the present application;

[0039] FIG8 is a cross-sectional view of a battery cell provided in some further embodiments of the present application;

[0040] FIG9 is an enlarged view of point C in FIG8 .

[0041] The accompanying drawings in the specific implementation manner are as follows:

[0042] 10. Casing; 101. First casing; 102. Second casing; 20. Battery cell; 201. Electrode assembly; 2011. Tab; 202. Casing; 2021. Welding portion; 2022. Wall portion; 2023. Recessed portion; 2024. Plating; 2025. Shell; 2026. End cap; 203. Coating; 204. Current collecting member; 1000. Vehicle; 100. Battery; 200. Controller; 300. Motor. DETAILED DESCRIPTION

[0043] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0044] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0045] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0047] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0048] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0049] In the embodiments of this application, "parallel" includes not only absolute parallelism but also approximately parallelism as commonly understood in engineering practice. Similarly, "perpendicular" also includes not only absolute perpendicularity but also approximately perpendicularity as commonly understood in engineering practice. For example, if the angle between two directions is 85°-90°, they are considered perpendicular; if the angle between two directions is 0°-5°, they are considered parallel.

[0050] The term "plurality" used in this application refers to two or more (including two).

[0051] Currently, judging by market developments, batteries are increasingly being used. They are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace.

[0052] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0053] The battery cell may be a secondary battery cell. A secondary battery cell refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0054] The battery cells can be lithium-ion battery cells, sodium-ion battery cells, sodium-lithium-ion battery cells, lithium metal battery cells, sodium metal battery cells, lithium-sulfur battery cells, magnesium-ion battery cells, nickel-hydrogen battery cells, nickel-cadmium battery cells, lead-acid battery cells, etc.

[0055] A battery cell may include an electrode assembly, an electrolyte, and a casing. The electrode assembly and electrolyte are housed in the casing, which encapsulates the electrode assembly, electrolyte, and other components. The electrode assembly includes a positive electrode, a negative electrode, and a separator that separates the positive and negative electrodes. The electrolyte conducts ions between the positive and negative electrodes.

[0056] The housing may include a shell and an end cover, wherein the end cover covers the opening of the shell, and the two together form a cavity for accommodating components such as the electrode assembly and the electrolyte.

[0057] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0058] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0059] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0060] In the prior art, the tabs of the electrode assembly in a battery cell are typically welded to the outer casing. However, welding damages the outer casing's anti-rust layer, rendering it ineffectively protected and making the welded area susceptible to corrosion, which is detrimental to improving the reliability of the battery cell.

[0061] To improve the reliability of a battery cell, some embodiments of the present application provide a battery cell comprising an electrode assembly, a housing, and a coating. The electrode assembly is housed within the housing, the housing having a weld portion electrically connected to a tab of the battery cell, and the coating is disposed on the exterior of the housing and covers the weld portion. By covering the weld portion with the coating, the weld portion is protected, reducing the likelihood of rust on the weld portion and thereby improving the reliability of the battery cell.

[0062] The battery cells described in the embodiments of this application are suitable for use in batteries and electrical devices using the batteries. The battery cells can be used in, but are not limited to, batteries. They can also be used in vehicles, aircraft, ships, electronic equipment, power tools, and other products, thereby improving the reliability of these products.

[0063] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. Vehicles can be fuel-powered, gas-powered, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles, or extended-range vehicles. Spacecraft include aircraft, rockets, space shuttles, and spacecraft. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0064] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0065] Please refer to Figure 1, which is a schematic structural diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an 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 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0066] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0067] Please refer to Figure 2, which is an exploded view of the battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and a battery cell 20, and the battery cell 20 is accommodated in the housing 10. Among them, the housing 10 is used to provide a storage space for the battery cell 20. There can be multiple battery cells 20 in the battery 100, and the multiple battery cells 20 can be connected in series, in parallel, or mixed. Mixed means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 can be directly connected in series, in parallel, or mixed together, and then the whole formed by the multiple battery cells 20 is accommodated in the housing 10; of course, the battery 100 can also be a battery module formed by first connecting multiple battery cells 20 in series, in parallel, or mixed, and then the multiple battery modules are connected in series, in parallel, or mixed to form a whole, and accommodated in the housing 10.

[0068] The housing 10 may include a first housing 101 and a second housing 102. The first housing 101 and the second housing 102 cover each other to define a storage space for accommodating the battery cells 20. The first housing 101 and the second housing 102 may have various shapes, such as a rectangular parallelepiped, a cylinder, etc. The first housing 101 may be a hollow structure with one side open, and the second housing 102 may also be a hollow structure with one side open. The open side of the second housing 102 covers the open side of the first housing 101, thereby forming the housing 10 with a storage space.

[0069] The battery 100 may further include other structures. For example, the battery 100 may further include a busbar component for achieving electrical connection between the plurality of battery cells 20 .

[0070] Each battery cell 20 may be a secondary battery or a primary battery, and may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0071] In some embodiments of the present application, as shown in Figures 3 and 4, the battery cell 20 includes an electrode assembly 201, a shell 202 and a coating 203. The electrode assembly 201 includes a pole ear 2011. The electrode assembly 201 is accommodated in the shell 202. The shell 202 is provided with a welding portion 2021, and the welding portion 2021 is electrically connected to the pole ear 2011; the coating 203 is arranged on the outside of the shell 202 and covers the welding portion 2021.

[0072] The electrode assembly 201 may be a component where an electrochemical reaction occurs in the housing 202. The housing 202 may contain one or more electrode assemblies 201. The electrode assembly 201 may be a wound structure or a laminated structure.

[0073] The electrode assembly 201 is in contact with the electrolyte, and active ions (e.g., lithium ions) can be conducted between the electrode assembly 201201 and the electrolyte. The electrode assembly 201 includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet, the negative electrode sheet, and the separator are stacked, and the separator is provided between the positive electrode sheet and the negative electrode sheet to prevent short circuits. Both the positive electrode sheet and the negative electrode sheet are provided with a tab 2011, which is used to extract or charge electrical energy.

[0074] The housing 202 is a component for encapsulating the electrode assembly 201 and the electrolyte. A cavity is formed in the housing 202, and the electrode assembly 201 and the electrolyte are disposed in the cavity and surrounded by the housing 202.

[0075] The housing 202 can have various shapes and sizes, such as a rectangular parallelepiped or a hexagonal prism. Specifically, the shape of the housing 202 can be determined based on the specific shape and size of the electrode assembly 201. The housing 202 can be made of various materials, including but not limited to copper, iron, aluminum, stainless steel, and aluminum alloys.

[0076] The welding portion 2021 may be a partial structure on the shell 202 , which is used to electrically connect to the tab 2011 of the electrode assembly 201 , so that the electrode assembly 201 is electrically connected to the shell 202 , and external devices can be electrically connected to the electrode assembly 201 through the shell 202 .

[0077] The coating 203 may be a layered structure disposed on the surface of the housing 202. By being disposed on the outer surface of the housing 202 and covering the weld 2021, the coating 203 protects the weld 2021, reduces the possibility of the weld 2021 coming into contact with the outside air, and helps reduce the possibility of rust on the weld 2021.

[0078] In the above structure, by covering the welding portion 2021 with the coating 203 , the welding portion 2021 is protected, which reduces the possibility of rusting of the welding portion 2021 , and is beneficial to improving the reliability of the battery cell 20 .

[0079] Illustratively, the tab 2011 can be connected to the inner side of the welding portion 2021 by welding, and the material of the tab 2011 and the material of the welding portion 2021 are melted together to achieve electrical connection between the tab 2011 and the welding portion 2021, which is beneficial to reducing the resistance between the tab 2011 and the welding portion 2021.

[0080] For example, as shown in Figures 5 and 6 , the tab 2011 can also be connected to the inner side of the welding portion 2021 via the current collector 204. The current collector 204 includes a welding structure, and the tab 2011 is welded to the current collector. The welding structure of the current collector is welded to the welding portion 2021. The material of the current collector 204 and the material of the welding portion 2021 are melted together, and the tab 2011 is electrically connected to the welding portion 2021 via the current collector 204. This helps to reduce the difficulty of electrically connecting the tab 2011 to the housing 202.

[0081] In some embodiments, the housing 202 includes a wall portion 2022 , a recess 2023 is provided on the outer side of the wall portion 2022 , and a welding portion 2021 is provided on the bottom wall of the recess 2023 ; at least a portion of the coating 203 is accommodated in the recess 2023 .

[0082] As shown in FIG. 7 , the housing 202 may include a shell 2025 and an end cover 2026 . The shell 2025 is formed with an opening, and the end cover 2026 covers the opening. The wall portion 2022 may be either the end cover 2026 or a wall structure in the shell 2025 .

[0083] The wall portion 2022 may be a wall structure within the housing 202. As shown in Figures 8 and 9, the recess 2023 may be a recessed structure formed by removing material from the wall portion 2022, which is used to accommodate the molten zone formed by welding in the welding portion 2021. By arranging the recess 2023 on the outside of the wall portion 2022 and providing the welding portion 2021 on the bottom wall of the recess 2023, the molten zone formed by welding the tab 2011 to the welding portion 2021 is located on the bottom wall of the recess 2023, thereby reducing the possibility of the molten zone protruding from the wall portion 2022 and thus reducing the possibility of the molten zone being bumped.

[0084] At least part of the coating 203 is contained in the recess 2023. The entire coating 203 may be contained in the recess 2023, and the molten zones of the coating 203 and the welding portion 2021 do not protrude from the wall 2022. Alternatively, part of the coating 203 may be contained in the recess 2023, and another part of the coating 203 protrudes from the recess 2023. Those skilled in the art can set whether the coating 203 protrudes from the recess 2023 according to actual conditions.

[0085] By accommodating at least a portion of the coating 203 within the recess 2023, the coating 203 fills the recess 2023 to protect the weld 2021. The recess 2023 also restricts the coating 203, positioning the coating 203 therein. This facilitates easier coverage of the coating 203 on the surface of the weld 2021. In some embodiments, the coating 203 can be formed by curing a coating. The coating 203 can be formed by self-leveling the coating in the recess 2023 and then curing it. Alternatively, the coating 203 can be formed by spraying the coating onto the bottom wall of the recess 2023 and then curing it. Under the restrictive effect of the recess 2023, the coating 203 can be easily formed on the bottom wall of the recess 2023.

[0086] In some embodiments, the coating 203 is entirely housed in the recess 2023 .

[0087] By accommodating the coating 203 as a whole in the recess 2023, the melting zones of the coating 203 and the welding portion 2021 are both located in the recess 2023, which helps to reduce the possibility of the melting zones and the coating 203 being bumped, which not only helps to extend the life of the coating 203, but also helps to improve the reliability of the connection between the tab 2011 and the welding portion 2021.

[0088] In some embodiments, the outer surface of the coating 203 is flush with the outer surface of the wall 2022 .

[0089] By making the outer surface of the coating 203 flush with the outer surface of the wall portion 2022 , the outer surface of the wall portion 2022 is made flat, which helps to improve the flatness of the appearance of the battery cell 20 .

[0090] In some embodiments, the coating layer 203 has a thickness H1, where 5 μm ≤ H1 ≤ 400 μm.

[0091] By setting the thickness of coating 203 to a range of 5 μm to 400 μm, coating 203 provides good protection without wasting paint due to excessive thickness. For example, 10 μm ≤ H1 ≤ 200 μm. By setting the thickness of coating 203 to a range of 10 μm to 200 μm, coating 203 not only provides good protection for weld 2021 but also reduces paint waste.

[0092] In some embodiments, the thickness of the coating 203 can be set to 15 μm, 30 μm, 50 μm, or 200 μm. Those skilled in the art can select the thickness of the coating 203 according to the assembly conditions of the battery cell 20 and external devices.

[0093] Whether the thickness of coating 203 meets the requirements can be determined using the grayscale value of coating 203. For example, the grayscale value corresponding to a thickness of 5 μm for coating 203 is set as a first preset value, and the grayscale value corresponding to a thickness of 400 μm for coating 203 is set as a second preset value. The first preset value is greater than the second preset value. If the grayscale value of coating 203 is greater than the first preset value, it can be determined that the thickness of coating 203 is less than 5 μm and does not meet the minimum thickness requirement for coating 203. If the grayscale value of coating 203 is less than the first preset value and greater than the second preset value, it can be determined that the thickness of coating 203 is greater than 5 μm and less than 400 μm, meeting the thickness requirement for coating 203. If the grayscale value of coating 203 is less than the second preset value, it can be determined that the thickness of coating 203 exceeds 400 μm and does not meet the requirements.

[0094] The coating 203 may also be a transparent coating 203 provided with a fluorescent agent. Whether the thickness of the coating 203 meets the requirements may be determined by the fluorescence intensity of the coating 203 .

[0095] In some embodiments, the housing further includes a plating layer 2024 disposed on the outer side of the wall portion 2022 , the plating layer 2024 surrounds the welding portion 2021 ; and the coating layer 203 is connected to the plating layer 2024 .

[0096] The coating 2024 can be a layered structure provided on the wall portion 2022. The coating 2024 can be a plastic layer or a metal layer, and those skilled in the art can configure it according to actual circumstances. In some embodiments, the wall portion 2022 can be made of carbon steel, and the coating 2024 provided on the outer surface thereof can be formed by nickel plating. The coating 2024 can protect the wall portion 2022 and reduce rust on the wall portion 2022.

[0097] The plating layer 2024 is arranged around the welding portion 2021, and the plating layer 2024 arranged outside the wall portion 2022 may be vacant at the welding portion 2021. When the welding portion 2021 is connected to the tab 2011 by welding, the plating layer 2024 outside the welding portion 2021 will be damaged, forming a vacancy there.

[0098] The coating 203 covering the welding portion 2021 is connected to the plating 2024. The projection of the coating 203 in the thickness direction of the wall portion 2022 may coincide with the projection of the vacancy of the plating 2024 in the thickness direction of the wall portion 2022, and the edge of the coating 203 is connected to the edge of the plating 2024. Alternatively, the projection of the coating 203 in the thickness direction of the wall portion 2022 may coincide with the projection of at least part of the plating 2024 in the thickness direction of the wall portion 2022, and in the overlapping part, the coating 203 adheres to the outer surface of the plating 2024.

[0099] In some embodiments, along the thickness direction of the wall portion 2022 , the projection of the welding portion 2021 is located within the range of the coating layer 203 .

[0100] By ensuring that the projection of the welding portion 2021 in the thickness direction of the shell 202 is within the range of the coating 203, the welding portion 2021 and the gaps in the plating layer 2024 are completely covered by the coating 203, which is conducive to providing more comprehensive protection, reducing the possibility of the welding portion 2021 contacting the air, and helping to reduce the possibility of the welding portion 2021 rusting.

[0101] In some embodiments, the thickness of the coating layer 2024 is H2, where 0.05 μm ≤ H2 ≤ 10 μm.

[0102] By setting the thickness of the coating 2024 to a range of 0.05 μm to 10 μm, the coating 2024 provides good protection without causing waste or increasing costs due to excessive thickness. For example, 0.1 μm ≤ H2 ≤ 5 μm. By setting the thickness of the coating 2024 to a range of 0.1 μm to 5 μm, the coating 2024 not only provides good protection for the wall portion 2022 but also reduces material waste.

[0103] In some embodiments, the thickness of the coating layer 2024 can be set to 0.5 μm, 1 μm, 2 μm, or 3 μm. Those skilled in the art can set the thickness of the coating layer 2024 according to actual conditions.

[0104] In some embodiments, the coating 203 includes a coating material including polyacrylate, polyurethane, or epoxy resin.

[0105] The coating material may refer to a material adhered to the outside of the housing 202 for forming the coating 203. In some embodiments, the coating material may be applied to the welding portion 2021 by spraying, so that the coating material adheres to the outside of the welding portion 2021 to form the coating 203 covering the welding portion 2021; the coating material may be applied to the welding portion 2021 by printing, so that the coating material adheres to the outside of the welding portion 2021 to form the coating 203 covering the welding portion 2021; or the coating material may be applied to the welding portion 2021 by dispensing, so that the coating material adheres to the outside of the welding portion 2021 to form the coating 203 covering the welding portion 2021.

[0106] The coating material includes polyacrylate, polyurethane or epoxy resin, which may refer to the core material of the coating material being polyacrylate, polyurethane or epoxy resin, and may also include materials such as organic silane, alkyl phosphate ester, etc. that can increase the adhesion of the material.

[0107] In some embodiments, the viscosity of the coating material ranges from 0.5 cps to 2000 cps.

[0108] By setting the viscosity range of the coating material to 0.5 cps to 2000 cps, the viscosity of the coating material can meet the requirements of coating processes such as spraying, printing, and dispensing, making it easier to apply the coating material to the welding portion 2021. For example, the viscosity range of the coating material can be set to 1 cps to 1000 cps, making it easier to apply the coating material to the welding portion 2021.

[0109] In some embodiments, the viscosity of the coating material can be set to 0.5 cps, 1 cps, 500 cps, or 800 cps. Those skilled in the art can set the viscosity of the coating material according to actual conditions so that the coating material can adapt to the coating process used.

[0110] For example, the viscosity of the coating material can be measured using a rotational viscometer according to the national standard GB / T 24148.4-2009. The specific measurement method can be referred to the national standard GB / T 24148.4-2009 and will not be described in detail here.

[0111] In some embodiments, the adhesion between the coating 203 and the welding portion 2021 ranges from level 0 to level 1.

[0112] By setting the adhesion between the coating 203 and the weld 2021 to be within the range of level 0 to level 1, the adhesion between the coating 203 and the weld 2021 is greater, the coating 203 can be firmly adhered to the weld 2021 and is not likely to fall off, which helps to extend the life of the coating 203. By setting the adhesion between the coating 203 and the weld 2021 to level 0 or level 1, the coating 203 is firmly adhered to the weld 2021 and is not likely to fall off.

[0113] For example, the adhesion of the coating 203 on the weld portion 2021 can be measured using the cross-hatch method according to the national standard GB / T 9286-1998. The specific measurement method can be referred to the national standard GB / T 9286-1998 and will not be repeated here.

[0114] In some embodiments, the hardness of the coating 203 is less than the hardness of the weld 2021 .

[0115] By setting the hardness of coating 203 to be lower than that of weld 2021, coating 203 is less likely to damage weld 2021 when battery cell 20 is bumped, thereby reducing the possibility of damage to weld 2021. The hardness of coating 203 and weld 2021 can both be Brinell hardness, which can be measured according to national standard GB / T 231.1-2019. The specific measurement method can be referred to national standard GB / T 231.1-2019 and will not be detailed here.

[0116] In some embodiments, the surface of the coating 203 has a certain surface tension, so that an adhesive can be provided on the coating 203 , and the adhesive can bond the outer surface of the battery cell 20 to other components.

[0117] In some embodiments, the distance L between the edge of the coating 203 and the edge of the welding portion 2021 is greater than or equal to 0.1 mm.

[0118] The edge of coating 203 extends beyond the edge of weld 2021 by more than 0.1 mm, which may mean that, in any direction perpendicular to the thickness of housing 202, the edge of coating 203 extends beyond the edge of weld 2021 by more than 0.1 mm. Along the thickness of housing 202, the projection of weld 2021 lies within the projection of coating 203, and the projection of coating 203 extends beyond the projection of weld 2021 by more than 0.1 mm. This ensures that coating 203 more completely covers weld 2021, enabling coating 203 to better protect weld 2021 and reducing the likelihood of rust on weld 2021.

[0119] For example, the distance that the edge of the coating 203 extends beyond the edge of the welding portion 2021 may be 0.5 mm, 0.8 mm, or 1 mm, so that the coating 203 has a better covering effect on the welding portion 2021 .

[0120] Some embodiments of the present application further provide a battery 100 , which includes the battery cell 20 provided by the above technical solution.

[0121] Some embodiments of the present application further provide an electrical device, which includes the battery 100 provided by the above technical solution, and the battery 100 is used to provide electrical energy.

[0122] Some embodiments of the present application provide a battery cell 20, as shown in Figures 8 and 9, the battery cell 20 includes an electrode assembly 201, a shell 202, a current collecting piece 204 and a coating 203, the electrode assembly 201 is accommodated in the shell 202, a recess 2023 is provided on the outside of the wall 2022 of the shell 202, a welding portion 2021 is provided on the bottom wall of the recess 2023, the tab 2011 of the electrode assembly 201 is welded to the current collecting piece 204, the current collecting piece 204 is welded to the welding portion 2021, the coating 203 is accommodated as a whole in the recess 2023 and covers the welding portion 2021, the coating 203 fills the recess 2023 and the outer surface of the coating 203 is flush with the outer surface of the wall 2022. In the above structure, by setting the coating 203 as a whole in the recess 2023 and filling the recess 2023, the welding portion 2021 can be better covered by the coating 203, which is beneficial to improving the protection of the welding portion 2021, and can better reduce the possibility of rust on the welding portion 2021, which is beneficial to improving the reliability of the battery cell 20.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, comprising: Electrode assembly, including tabs; A shell, wherein the electrode assembly is accommodated in the shell, and the shell is provided with a welding portion, and the welding portion is electrically connected to the electrode lug; as well as A coating is disposed on the outer side of the shell and covers the welding portion.

2. The battery cell according to claim 1, wherein: The housing comprises a wall portion, a recess is provided on the outer side of the wall portion, and the bottom wall of the recess is provided with the welding portion; At least a portion of the coating is received in the recess.

3. The battery cell according to claim 2, wherein: The coating layer is entirely accommodated in the recess.

4. The battery cell according to claim 3, wherein: The outer surface of the coating is flush with the outer surface of the wall.

5. The battery cell according to any one of claims 1 to 4, wherein: The thickness of the coating is H1, 5 μm≤H1≤400 μm.

6. The battery cell according to claim 5, wherein: 10μm≤H1≤200μm.

7. The battery cell according to any one of claims 2 to 4, wherein: The shell further comprises a plating layer arranged on the outer side of the wall portion, the plating layer surrounds the welding portion; and the coating layer is connected to the plating layer.

8. The battery cell according to claim 7, wherein: Along the thickness direction of the wall portion, a projection of the welding portion is located within the range of the coating layer.

9. The battery cell according to any one of claims 7 to 8, wherein: The wall portion is a carbon steel structure, and the plating layer is a nickel plating layer.

10. The battery cell according to any one of claims 7 to 9, wherein: The thickness of the coating is H2, 0.05 μm≤H2≤10 μm.

11. The battery cell according to any one of claims 7 to 10, wherein: 0.1μm≤H2≤5μm.

12. The battery cell according to any one of claims 1 to 11, wherein: The coating layer includes a coating material including polyacrylate, polyurethane or epoxy resin.

13. The battery cell according to claim 12, wherein: The viscosity of the coating material ranges from 0.5 cps to 2000 cps.

14. The battery cell according to claim 13, wherein: The viscosity of the coating material ranges from 1 cps to 1000 cps.

15. The battery cell according to any one of claims 1 to 14, wherein: The adhesion between the coating and the welding portion ranges from level 0 to level 1.

16. The battery cell according to any one of claims 1 to 15, wherein: The hardness of the coating layer is lower than the hardness of the welding portion.

17. The battery cell according to any one of claims 1 to 16, wherein: The distance that the edge of the coating exceeds the edge of the welding portion is L, and L>0.1 mm.

18. A battery comprising the battery cell according to any one of claims 1 to 17.

19. An electrical device comprising the battery according to claim 18, wherein the battery is used to provide electrical energy.

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