Battery cell, battery device, electric device, and battery cell processing method

Abstract

Disclosed in embodiments of the present application are a battery cell, a battery device, an electric device, and a battery cell processing method. The battery cell comprises: a casing defining an accommodating cavity having an opening; an electrode assembly accommodated in the accommodating cavity; and an end cover welded to the casing and covering the opening, wherein a weld seam is formed at the joint between the end cover and the casing. The casing comprises a first region close to the weld seam, the hardness of at least part of the first region is H1, H1 satisfies: 35 HV≤H1≤60 HV, and the first region is a region in the casing positioned at a distance of 0.1 mm to 0.3 mm from the edge of the weld seam. The battery cell, the battery device, the electric device, and the battery cell processing method in the embodiments of the present application can improve the deformation resistance of the battery cell and prolongs its service life.

Description

Methods for handling individual battery cells, battery devices, electrical devices, and individual battery cells.

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411035451.9, filed on July 30, 2024, entitled “Battery cell, battery device, power supply device and method for processing battery cell”, the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. In this context, electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the automotive industry's sustainable development. And for electric vehicles, battery technology is a crucial factor in their development.

[0005] In the development of battery technology, besides improving battery device performance, safety is also a crucial issue. If the safety of a battery device cannot be guaranteed, it will be unusable or have a short lifespan. Therefore, how to improve battery device performance while simultaneously enhancing safety and lifespan has become a particularly important problem in the development of battery technology. Summary of the Invention

[0006] This application provides a method for processing battery cells, battery devices, electrical devices, and battery cells, which can improve the deformation resistance and service life of battery cells.

[0007] In a first aspect, a battery cell is provided, comprising: a housing forming a receiving cavity with an opening; an electrode assembly received in the receiving cavity; an end cap welded to the housing and covering the opening, wherein a weld is formed at the connection between the end cap and the housing; the housing includes a first region adjacent to the weld, at least a portion of the first region having a hardness of H1, wherein H1 satisfies: 35HV≤H1≤60HV, and the first region is a region in the housing between 0.1 mm and 0.3 mm from the edge of the weld.

[0008] Therefore, in the battery cell of this application embodiment, by increasing the hardness of the first region near the weld seam, so that the hardness H1 of at least a portion of the region exceeds 35 HV, the structural strength of the first region of the battery cell is increased, effectively resisting deformation during use. This makes the casing less prone to cracking during use, thereby improving the service life and reliability of the battery cell, and also improving the safety performance of the battery. Furthermore, controlling the hardness H1 of at least a portion of the first region to not exceed 60 HV reduces the processing difficulty and cost of the battery cell.

[0009] In some embodiments, the housing further includes a second region remote from the weld, at least a portion of which has a hardness of H2, where H1 and H2 satisfy: H2-H1≤15HV. This second region is a portion of the housing located 5.0 mm to 6.0 mm from the edge of the weld. Reducing the hardness difference between the first and second regions can decrease the hardness variation between different areas of the housing, improve the structural strength of different areas of the housing, reduce the risk of localized structural failure, and thus improve the structural stability and reliability of the housing.

[0010] In some embodiments, H1 and H2 satisfy: H2-H1≤10HV, which further reduces the hardness difference between the first and second regions of the shell and reduces the risk of local structural failure of the shell.

[0011] In some embodiments, the thickness of at least a portion of the second region ranges from [0.4 mm, 0.7 mm], and H2 satisfies: 45HV ≤ H2 ≤ 75HV. Appropriately increasing the thickness of at least a portion of the second region can improve the structural stability of the casing and reduce processing difficulty; simultaneously, the thickness of at least a portion of the second region should be limited to no more than 0.7 mm to increase the energy density of the battery cell. Furthermore, when limiting the thickness of the second region, the impact of its hardness H2 must also be considered to ensure that the hardness of the second region meets design requirements, thereby improving the structural stability and reliability of the casing, reducing processing difficulty, and increasing processing efficiency.

[0012] In some embodiments, the density of the first region is greater than the density of the second region. By increasing the density of the first region, the hardness of the first region can be increased.

[0013] In some embodiments, the hardness of the surface of the first region away from the interior of the battery cell is greater than the hardness of the surface of the first region facing the interior of the battery cell. The hardness can be increased only in a localized area of ​​the first region to reduce processing difficulty.

[0014] In some embodiments, H1 satisfies: H1≥40HV, further increasing the hardness of at least a portion of the first region, thereby making the structural strength of the first region of the battery cell stronger, and improving the service life and reliability of the battery cell.

[0015] In some embodiments, the housing is made of aluminum to facilitate processing and reduce costs.

[0016] In some embodiments, the housing is made of ternary aluminum alloy, which is low in material cost, easy to process, and can effectively improve the processing efficiency of the housing 21.

[0017] In some embodiments, the electrode assembly is a stacked structure, comprising a plurality of positive electrode sheets and a plurality of negative electrode sheets, which are stacked along a first direction. The housing includes a first wall and a second wall perpendicular to the first direction and disposed opposite to each other, with the first region located on the first wall and / or the second wall. Increasing the hardness of at least a portion of the first wall and / or the second wall can improve the structural strength of the first wall and / or the second wall, reduce the risk of cracking of the first wall and / or the second wall near the weld, and thus improve the structural stability and reliability of the battery cell.

[0018] In some embodiments, the number of the plurality of negative electrode sheets is greater than the number of the plurality of positive electrode sheets, and a positive electrode sheet is disposed between two adjacent negative electrode sheets in the plurality of negative electrode sheets to reduce lithium plating and improve the performance of the battery cell.

[0019] In some embodiments, each of the plurality of negative electrode plates is provided with a negative electrode tab; and / or, each of the plurality of positive electrode plates is provided with a positive electrode tab, so as to facilitate the output of electrical energy.

[0020] In some embodiments, the first region is disposed around the housing to increase the structural strength of each region of the housing in the circumferential direction, thereby maximizing the structural strength of the housing and thus improving the service life and reliability of the battery cell.

[0021] In a second aspect, a battery device is provided, comprising a battery cell as described in any embodiment of the first aspect.

[0022] In some embodiments, the battery device includes a plurality of battery cells arranged along a second direction, wherein the battery cells located at both ends of the second direction are battery cells as described in any embodiment of the first aspect. Due to mutual compression and fixation, the battery cells located at both ends of the second direction deform more than other battery cells. Therefore, by at least setting the battery cells at both ends of the second direction to be the battery cells of the embodiments of this application, the hardness of at least a portion of the first region of the casing of the battery cells at both ends is increased, which can better resist deformation, reduce the risk of localized cracking of battery cells inside the battery, and thus improve the reliability and stability of the battery device.

[0023] Thirdly, an electrical device is provided, including a battery device as described in any embodiment of the second aspect, the battery device being used to provide electrical energy to the electrical device.

[0024] Fourthly, a method for processing a battery cell is provided, comprising: providing a battery cell including a housing, an electrode assembly, and an end cap, the housing forming a receiving cavity with an opening, the electrode assembly being received in the receiving cavity, the end cap being welded to the housing and covering the opening, a weld being formed at the connection between the end cap and the housing, the housing including a first region adjacent to the weld; hardening the first region, wherein at least a portion of the first region after the hardening treatment has a hardness of H1, H1 satisfying: 35HV≤H1≤60HV, the first region being a region in the housing between 0.1mm and 0.3mm from the edge of the weld.

[0025] In some embodiments, the hardening treatment of the first region includes: rolling the first region.

[0026] In some embodiments, the hardening process on the first region includes: laser processing of the first region.

[0027] In some embodiments, the housing further includes a second region away from the weld, at least a portion of which has a hardness of H2, where H1 and H2 satisfy: H2-H1≤15HV, and the second region is a region in the housing located between 5.0 mm and 6.0 mm from the edge of the weld.

[0028] In some embodiments, the housing is made of aluminum.

[0029] In some embodiments, the housing is made of tri-series aluminum alloy.

[0030] Therefore, the battery cell processing method of this application embodiment increases the hardness of the first region near the weld, making the hardness H1 of at least a portion of it exceed 35HV. This increases the structural strength of the first region of the battery cell, effectively resisting deformation during use and making this part of the casing less prone to cracking, thereby improving the service life and reliability of the battery cell and enhancing the safety performance of the battery device. Furthermore, controlling the hardness H1 of at least a portion of this first region to not exceed 60HV reduces the processing difficulty and cost of the battery cell. Attached Figure Description

[0031] Figure 1 is a schematic diagram of a vehicle according to an embodiment of this application.

[0032] Figure 2 is an exploded view of a battery device according to an embodiment of this application.

[0033] Figure 3 is a schematic diagram of the structure of a battery cell according to an embodiment of this application.

[0034] Figure 4 is a partial structural exploded view of a battery cell according to an embodiment of this application.

[0035] Figure 5 is a top view of a single battery cell according to an embodiment of this application.

[0036] Figure 6 is a schematic cross-sectional view of the battery cell in Figure 5 along the A-A' direction.

[0037] Figure 7 is a magnified structural diagram of region B in Figure 6.

[0038] Figure 8 is a schematic flowchart of a method for processing a single battery cell according to an embodiment of this application. Detailed Implementation

[0039] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0042] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0043] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0044] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0045] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0046] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0047] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0048] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0049] In some implementations, the battery cell in this application embodiment can be a metal battery. Specifically, the metal battery may include lithium metal secondary batteries, sodium metal batteries, or magnesium metal batteries, etc. This application embodiment does not limit this.

[0050] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0051] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

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

[0053] As an example, the positive electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0054] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0055] In some embodiments, the negative electrode may be a negative electrode sheet, which may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0056] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0057] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0058] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0059] In some embodiments, the separator is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0060] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride, and ceramic.

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

[0062] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0063] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0064] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc. The housing includes a shell and end caps.

[0065] The battery device mentioned in the embodiments of this application may include a single physical module containing one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, parallel, or mixed via a busbar.

[0066] In some embodiments, the battery device may be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0067] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0068] In some embodiments, the battery device may be located within an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0069] A battery cell typically consists of a casing and end caps, which are sealed together using heat treatment methods such as welding. However, during the welding process, the area around the weld seam on the casing and end caps is affected by heat, altering the material properties of this area. This reduces the structural strength of the battery cell's casing in that area, making it more susceptible to damage and failure during battery cell use, thus shortening the battery cell's lifespan.

[0070] In view of this, embodiments of this application provide a battery cell, a battery device, an electrical device, and a method for processing the battery cell, which can solve the above-mentioned problems. The battery cell of this application includes a housing, an end cap, and an electrode assembly. The housing has an opening and a receiving cavity, the electrode assembly is received within the receiving cavity, and the end cap is used to close the opening of the housing. The end cap and the housing can be connected by welding, thus forming a weld between the end cap and the housing. The housing includes a first region near the weld, which is a region of the housing between 0.1 mm and 0.3 mm from the edge of the weld. At least a portion of the first region has a hardness of H1, where H1 satisfies: 35HV ≤ H1 ≤ 60HV, where HV is Vickers Hardness (HV). Due to the welding process between the casing and the end cap, the hardness of the first region near the weld is typically low. However, this embodiment increases the hardness of the first region near the weld, ensuring that at least a portion of it has a hardness H1 exceeding 35 HV. This increases the structural strength of the first region of the battery cell, effectively resisting deformation during use and making this part of the casing less prone to cracking. This improves the battery cell's lifespan and reliability, while also enhancing the safety performance of the battery device. Furthermore, controlling the hardness H1 of at least a portion of this first region to not exceed 60 HV reduces the difficulty and cost of battery cell processing.

[0071] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery-powered devices. These electrical devices can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of this application include, but are not limited to, the above-mentioned electrical devices.

[0072] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0073] Figure 1 shows a schematic diagram of a vehicle 1 according to one embodiment of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A motor 90, a controller 80, and a battery device 10 can be installed inside vehicle 1. The controller 80 controls the battery device 10 to supply power to the motor 90. For example, the battery device 10 can be installed at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1. For example, the battery device 10 can serve as the operating power source for vehicle 1, for example, to meet the electrical system needs of vehicle 1 for starting, navigation, and operation. In another embodiment of this application, the battery device 10 can not only serve as the operating power source for vehicle 1, but also as the driving power source for vehicle 1, replacing or partially replacing gasoline or natural gas to provide driving power for vehicle 1.

[0074] To meet different power demands, the battery device 10 may include multiple battery cells, which can be connected in series, parallel, or a combination thereof. The battery device 10 may also be referred to as a battery pack. Optionally, multiple battery cells can first be connected in series, parallel, or a combination thereof to form a battery module, and then multiple battery modules can be connected in series, parallel, or a combination thereof to form the battery device 10. In other words, multiple battery cells can directly form the battery device 10, or they can first be formed into battery modules, and then the battery modules can be combined to form the battery device 10.

[0075] Figure 2 shows a schematic diagram of a battery device 10 according to an embodiment of this application. The battery device 10 may include a plurality of battery cells 20. The battery device 10 may also include a housing 11, which has a hollow interior structure, and the plurality of battery cells 20 are housed within the housing 11. Figure 2 shows a possible implementation of the housing 11 according to an embodiment of this application. As shown in Figure 2, the housing 11 may include two housing sections, referred to here as a first housing section 111 and a second housing section 112, which are fastened together. The shapes of the first housing section 111 and the second housing section 112 may be determined according to the shape of the combination of the plurality of battery cells 20, and at least one of the first housing section 111 and the second housing section 112 has an opening. For example, as shown in Figure 2, both the first housing portion 111 and the second housing portion 112 can be hollow cuboids with only one open side. The openings of the first housing portion 111 and the second housing portion 112 are opposite to each other, and the first housing portion 111 and the second housing portion 112 are interlocked to form a housing 11 with a closed cavity. This cavity can accommodate multiple battery cells 20. The multiple battery cells 20 are connected in parallel, series, or mixed and placed inside the housing 11 formed by the interlocking of the first housing portion 111 and the second housing portion 112.

[0076] For example, unlike what is shown in Figure 2, only one of the first box portion 111 and the second box portion 112 may be a hollow cuboid with an opening, while the other is plate-shaped to cover the opening. For example, taking the second box portion 112 as a hollow cuboid with only one side being an opening, and the first box portion 111 as a plate-shaped example, then the first box portion 111 covers the opening of the second box portion 112 to form a box 11 with a closed cavity. The embodiments of this application are not limited to this.

[0077] Figure 3 shows a structural schematic diagram of a battery cell 20 provided in an embodiment of this application; Figure 4 shows an exploded structural schematic diagram of a battery cell 20 provided in an embodiment of this application, for example, Figure 4 can be an exploded structural schematic diagram of the battery cell 20 shown in Figure 3; Figure 5 shows a top view schematic diagram of a battery cell 20 provided in an embodiment of this application, for example, Figure 5 can be a top view schematic diagram of the battery cell 20 shown in Figures 3 and 4; Figure 6 shows a partial cross-sectional schematic diagram of a battery cell 20 provided in an embodiment of this application, the cross-section being perpendicular to the length direction X of the battery cell 20, for example, Figure 6 can be a partial cross-sectional schematic diagram along the A-A' direction shown in Figure 5; Figure 7 shows an enlarged partial cross-sectional schematic diagram of a battery cell 20 provided in an embodiment of this application, for example, Figure 7 is an enlarged view of region B shown in Figure 6.

[0078] As shown in Figures 3 to 7, the battery cell 20 of this embodiment includes a housing 21, an electrode assembly 23, and an end cap 22. The housing 21 forms a receiving cavity 212 with an opening 211; the electrode assembly 23 is received in the receiving cavity 212; the end cap 22 is welded to the housing 21 and covers the opening 211, and a weld 24 is formed at the connection between the end cap 22 and the housing 21; the housing 21 includes a first region 213 near the weld 24, and at least a portion of the first region 213 has a hardness of H1, where H1 satisfies: 35HV≤H1≤60HV, and the first region 213 is a region in the housing 21 between 0.1mm and 0.3mm from the edge of the weld 24.

[0079] As shown in Figures 3 to 7, the casing 21 of the battery cell 20 is a hollow structure with at least one opening 211, and the end cap 22 is used to cover the opening 211 of the casing 21. If the casing 21 is a hollow structure with an opening 211 at one end, then one end cap 22 can be set accordingly and cover the opening 211 of the casing 21; if the casing 21 is a hollow structure with openings 211 at both opposite ends, then two end caps 22 can be set, and the two end caps 22 respectively cover the openings 211 at both ends of the casing 21.

[0080] It should be understood that the battery cell 20 in this application embodiment can be a cylindrical battery cell 20, a prismatic battery cell 20, a pouch battery, or a battery cell 20 of other shapes. Among them, the prismatic battery cell 20 may include a prismatic battery cell 20, a blade-shaped battery cell 20, or other polyprismatic battery cells 20, such as a hexagonal prismatic battery cell 20 or an octagonal prismatic battery cell 20, and the embodiments of this application are not limited thereto.

[0081] Corresponding to different shapes of battery cells 20, the casing 21 of the battery cell 20 can be of various shapes, such as a cylinder or a polygonal prism. In this embodiment, the shapes of the casing 21 and the end cap 22 are mutually compatible. For example, if the casing 21 is an approximately cuboid structure, the end cap 22 can be an approximately rectangular plate structure adapted to the casing 21, or the end cap 22 can be a groove structure with an opening to cover the opening 211 of the casing 21. Furthermore, the end cap 22 can be any wall of the battery cell 20. For example, the end cap 22 can be the wall with the largest area, the wall with the smallest area, or other walls. This embodiment is not limited to these.

[0082] For example, as shown in Figures 3 to 7, in this embodiment, the shell 21 is mainly described as a hollow cuboid structure, and the corresponding end cap 22 is an approximately rectangular plate structure. Additionally, this embodiment mainly uses a hollow structure with an opening 211 at one end as an example. However, the relevant descriptions of this embodiment are also applicable to battery cells 20 of other shapes; for simplicity, they will not be elaborated upon here.

[0083] For ease of description, this application defines three reference directions in its embodiments. The thickness direction of the battery cell 20 is direction Y, the height direction of the battery cell 20 is direction Z, and the length direction of the battery cell 20 is direction X. The thickness direction Y, the height direction Z, and the length direction X of the battery cell 20 are perpendicular to each other, and the dimension of the battery cell 20 in the thickness direction Y is smaller than the dimension in the length direction X.

[0084] It should be understood that the end cap 22 in this embodiment is used to cover the opening 211 of the housing 21 to isolate the internal environment of the battery cell 20 from the external environment. The housing 21 in this embodiment has a receiving cavity 212 for accommodating an electrode assembly 23, which is a component in the battery cell 20 where an electrochemical reaction occurs. Depending on actual usage requirements, one or more electrode assemblies 23 may be provided within the battery cell 20.

[0085] In this embodiment, the end cap 22 covers the opening 211 of the housing 21. The end cap 22 and the housing 21 can be connected by welding, forming a weld 24 at the connection between the end cap 22 and the housing 21. Specifically, during welding, melting occurs at the connection between the end cap 22 and the housing 21. After welding, the molten metal in the molten pool cools and solidifies to form the weld 24, which enables a sealed connection between the end cap 22 and the housing 21. In metallographic images, the weld 24 typically appears as dendrites. Furthermore, to ensure the seal between the end cap 22 and the housing 21, the weld 24 typically surrounds both the end cap 22 and the opening 211 of the housing 21.

[0086] It should be understood that around weld 24, the shell 21 includes a heat-affected zone 215. This heat-affected zone 215 is affected by the welding process between the end cap 22 and the shell 21, resulting in changes in its microstructure and properties. In metallographic diagrams, this heat-affected zone 215 typically exhibits an equiaxed crystal morphology and has a relatively clear boundary with weld 24. Specifically, under the action of welding thermal cycling, the region around weld 24 where the solid base material undergoes significant changes in microstructure and properties is called the heat-affected zone 215. The heat-affected zone 215 is typically located around weld 24; the closer the region is to weld 24, the greater the heat impact, and the farther away the region is from weld 24, the smaller the heat impact.

[0087] It should be understood that the housing 21 in this embodiment includes a first region 213 near the weld 24. The first region 213 is a region in the housing 21 between 0.1 mm and 0.3 mm from the edge of the weld 24. The first region 213 in this embodiment is a part of the heat-affected zone 215. Specifically, as shown in Figures 3 to 7, along the height direction Z of the battery cell 20, i.e., the thickness direction Z of the end cap 22, the edge of the weld 24 near the heat-affected zone 215 is the boundary line between the weld 24 and the heat-affected zone 215. Extending a distance L1 from the edge of the weld 24 into the heat-affected zone 215, this distance L1 is 0.1 mm; and extending a distance L2 from the edge of the weld 24 into the heat-affected zone 215, this distance L2 is 0.3 mm. The region between distances L1 and L2 is the first region 213.

[0088] In this embodiment, the hardness of at least a portion of the first region 213 is H1, where H1 satisfies: 35HV ≤ H1 ≤ 60HV. Due to the influence of welding between the casing 21 and the end cap 22, the hardness of the first region 213 near the weld 24 is usually low. However, this embodiment increases the hardness of the first region 213 near the weld 24, making the hardness H1 of at least a portion of it exceed 35HV. This increases the structural strength of the first region 213 of the battery cell 20, effectively resisting deformation of the battery cell 20 during use. This makes the casing 21 less prone to cracking during use, thereby improving the service life and reliability of the battery cell 20, and also improving the safety performance of the battery device 10. In addition, controlling the hardness H1 of at least a portion of the first region 213 to not exceed 60HV reduces the processing difficulty and cost of the battery cell 20.

[0089] In some embodiments, the hardness H1 of at least a portion of the first region 213 in this application embodiment can be further set to satisfy other value ranges. For example, H1 satisfies: H1≥40HV, which further increases the hardness of at least a portion of the first region 213, making the structural strength of the first region 213 of the battery cell 20 stronger, thereby improving the service life and reliability of the battery cell 20.

[0090] In some embodiments, the hardness H1 of at least a portion of the first region 213 may be specifically set to the following values ​​or any two of the following values: 35HV, 38HV, 40HV, 43HV, 45HV, 48HV, 50HV, 53HV, 55HV, 58HV, and 60HV.

[0091] In some embodiments, opposite to the heat-affected zone 215, the housing 21 also includes a non-affected zone 216, which is located on the side of the heat-affected zone 215 away from the weld 24. The non-affected zone 216 is further away from the hot spots on the housing 21 of the battery cell 20, and compared to the heat-affected zone 215, the solid substrate in the non-affected zone 216 of the housing 21 is essentially unaffected by heat or experiences less heat. That is, the edge forming the opening 211 of the housing 21 is the connection point between the end cap 22 and the housing 21, and the housing 21 and the end cap 22 are typically welded at this connection point to form the weld 24. When the housing 21 has an opening 211 at one end, for example, as shown in Figures 3 to 7, the sidewall of the housing 21 sequentially includes a weld 24, a heat-affected zone 215, and a non-affected zone 216 in the direction from the opening 211 to the bottom wall of the housing 21. The sidewall of the housing 21 is the wall of the housing 21 used to enclose and form the opening 211, and the bottom wall of the housing 21 is the wall opposite to the opening 211. In one possible embodiment, the housing 21 may also have openings 211 at both ends. In this case, in the thickness direction Z of the end cap 22, the welds 24 are located in the opening 211 regions at both ends of the housing 21, the non-affected zone 216 is located in the middle region of the sidewall of the housing 21, and the heat-affected zone 215 is located between the welds 24 on both sides and the non-affected zone 216.

[0092] Compared to the heat-affected zone 215, the unaffected zone 216 is less affected by the welding process. Therefore, the material parameters and properties of the unaffected zone 216 remain basically unchanged from those of the shell 21 before welding. For example, in a metallographic image, the unaffected zone 216 is usually in the form of strip-shaped crystals and has a relatively clear boundary with the heat-affected zone 215.

[0093] It should be understood that the housing 21 in this embodiment of the application also includes a second region 214 away from the weld 24. The second region 214 is a region in the housing 21 between 5.0 mm and 6.0 mm away from the edge of the weld 24. The second region 214 in this embodiment of the application is a part of the non-affected area 216. Specifically, as shown in Figures 3 to 7, along the height direction Z of the battery cell 20, that is, the thickness direction Z of the end cap 22, the edge of the weld 24 near the heat-affected area 215 is the boundary line between the weld 24 and the heat-affected area 215. Extending a distance L3 from the edge of the weld 24 towards the non-affected area 216, the distance L3 is 2 mm; and extending a distance L4 from the edge of the weld 24 towards the non-affected area 216, the distance L4 is 4 mm. The region between distance L3 and distance L4 is the second region 214.

[0094] In this embodiment of the application, at least a portion of the second region 214 has a hardness of H2, and H1 and H2 satisfy: H2-H1≤15HV. Reducing the hardness difference between the first region 213 and the second region 214 can reduce the hardness difference between different regions of the shell 21, improve the structural strength of different regions of the shell 21, reduce the risk of local structural failure of the shell 21, and thus improve the structural stability and reliability of the shell 21.

[0095] In some embodiments, the difference between the hardness H2 of at least a portion of the second region 214 and the hardness H1 of at least a portion of the first region 213 can be further set to satisfy other value ranges. For example, H1 and H2 satisfy: H2-H1≤10HV, which further reduces the hardness difference between the first region 213 and the second region 214 of the housing 21 and reduces the risk of local structural failure of the housing 21.

[0096] In some embodiments, the difference H2-H1 between the hardness H2 of at least a portion of the second region 214 and the hardness H1 of at least a portion of the first region 213 can be specifically set to the following values ​​or any two of the following values: 15HV, 13HV, 10HV, 8HV, 5HV, 3HV, 0HV or any negative number, that is, the hardness H2 of at least a portion of the second region 214 can be greater than, equal to or less than the hardness H1 of at least a portion of the first region 213.

[0097] In this embodiment, the specific value of the hardness H2 of at least a portion of the second region 214 of the housing 21 can be set according to actual application. For example, the hardness H2 of at least a portion of the second region 214 is usually related to the thickness and material of that portion of the region. For another example, the thickness T of at least a portion of the second region 214 can range from [0.4 mm, 0.7 mm], and H2 satisfies: 45 HV ≤ H2 ≤ 75 HV. Appropriately increasing the thickness T of at least a portion of the second region 214 can improve the structural stability of the housing 21 and reduce processing difficulty; at the same time, the thickness T of at least a portion of the second region 214 should be limited to no more than 0.7 mm to improve the energy density of the battery cell 20. Furthermore, when limiting the thickness T of the second region 214, the influence of the hardness H2 of the second region 214 also needs to be considered so that the hardness of the second region 214 meets the design requirements, which can improve the structural stability and reliability of the housing 21, reduce processing difficulty, and improve processing efficiency.

[0098] It should be understood that at least a portion of the second region 214 in this embodiment has a hardness of H2, and correspondingly, the thickness of that portion of the second region 214 is T. That is, the hardness H2 and the thickness T are parameters of the same region of the second region 214.

[0099] It should be understood that in this embodiment, the weld 24 surrounds the opening 211 of the housing 21 to seal the battery cell 20. Correspondingly, the heat-affected zone 215 also surrounds the housing 21 and is close to the opening 211. Along the circumference of the heat-affected zone 215, the first region 213 can be at least a portion of the heat-affected zone 215. Similarly, the non-affected zone 216 is also arranged around the housing 21, and along the circumference of the non-affected zone 216, the second region 214 can be at least a portion of the non-affected zone 216. This embodiment is not limited to this.

[0100] In some embodiments, a first region 213 is disposed around the housing 21, that is, along the circumference of the opening 211 of the housing 21. This first region 213 surrounds the housing 21 to increase the structural strength of each region of the housing 21 in the circumferential direction. Since the weld 24 surrounds the opening 211 of the housing 21, correspondingly, when the first region 213 is disposed around the housing 21, the structural strength of the region near the weld 24 on each sidewall of the housing 21 is increased, which can maximize the structural strength of the housing 21, thereby improving the service life and reliability of the battery cell 20.

[0101] In some embodiments, the second region 214 is disposed around the housing 21, that is, along the circumference of the opening 211 of the housing 21, the second region 214 surrounds the housing 21.

[0102] In some embodiments, the first region 213 may also be provided only in a portion of the circumferential region of the opening 211 of the housing 21. For example, considering that some areas of the housing 21 are subjected to large deformation forces during use, the first region 213 may also be provided on the wall of the housing 21 with a large amount of deformation, and the hardness of the first region 213 may satisfy H1.

[0103] For example, electrode assembly 23 includes multiple layers of electrode sheets stacked along a first direction, and housing 21 includes a first wall 217 and a second wall 218 perpendicular to and opposite to the first direction, with a first region 213 located on the first wall 217 and / or the second wall 218. As shown in Figures 3 to 7, taking the first direction as the thickness direction Y of battery cell 20 as an example, when the multiple layers of electrode sheets of electrode assembly 23 are arranged along the first direction Y, during the use of battery cell 20, electrode assembly 23 expands, and the deformation of battery cell 20 in the first direction Y is relatively large. That is, the deformation force borne by the first wall 217 and the second wall 218 of housing 21, which are opposite to each other along the first direction Y, is relatively greater than that of other walls. Therefore, by setting the first region 213 to be located on the first wall 217 and / or the second wall 218, the hardness of at least a portion of the first wall 217 and / or the second wall 218 is increased, which can effectively improve the structural strength of the first wall 217 and / or the second wall 218, reduce the risk of cracking of the first wall 217 and / or the second wall 218 near the weld 24, and thus improve the structural stability and reliability of the battery cell 20.

[0104] In some embodiments, the first wall 217 and the second wall 218 are typically the walls with the largest area of ​​the battery cell 20.

[0105] In the embodiments of this application, for any electrode assembly 23, the electrode assembly 23 may include a tab 232 and an electrode body portion 231. Specifically, as shown in Figures 3 to 7, the electrode assembly 23 may include at least two tabs 232, which may include at least one positive tab 232a and at least one negative tab 232b. The positive tab 232a may be formed by stacking the portion of the positive electrode sheet that is not coated with a positive active material layer, while the portion of the positive electrode sheet coated with a positive active material layer may be formed into the electrode body portion 231 by winding or stacking. The negative tab 232b may be formed by stacking the portion of the negative electrode sheet that is not coated with a negative active material layer, while the portion of the negative electrode sheet coated with a negative active material layer may be formed into the electrode body portion 231 by winding or stacking.

[0106] In some embodiments, the electrode assembly 23 is a stacked structure, which includes a plurality of positive electrode plates and a plurality of negative electrode plates. The plurality of positive electrode plates and the plurality of negative electrode plates are stacked along a first direction Y to form a stacked electrode assembly 23.

[0107] In some embodiments, in the electrode assembly 23, the number of multiple negative electrode sheets is greater than the number of multiple positive electrode sheets, and a positive electrode sheet is disposed between two adjacent negative electrode sheets to reduce lithium plating on the electrode sheets and improve the performance of the battery cell 20.

[0108] In some embodiments, each of the plurality of negative electrode plates is provided with a negative electrode tab 232b; and / or, each of the plurality of positive electrode plates is provided with a positive electrode tab 232a, the positive electrode tab 232a being used to be electrically connected to the positive electrode terminal 221a, and the negative electrode tab 232b being used to be electrically connected to the negative electrode terminal 221b, so as to output electrical energy.

[0109] In this embodiment, the plurality of tabs 232 of the electrode assembly 23 can be located on the same or different end faces of the electrode assembly 23. For example, the electrode assembly 23 may include two tabs 232 with opposite polarities. These two tabs 232 may be located on the same end face, or they may be located on different end faces. For example, the two tabs 232 may be located on opposite end faces. This embodiment is not limited to this. For ease of explanation, as shown in Figures 3 to 7, this embodiment mainly uses the example of electrode assembly 23 including tabs 232 with opposite polarities located on the same end face of the electrode assembly 23.

[0110] In some embodiments, the battery cell 20 of this application may further be provided with electrode terminals 221 on its housing 21. The electrode terminals 221 are used to electrically connect with the electrode assembly 23 to output the electrical energy of the battery cell 20. As shown in Figures 3 to 7, the battery cell 20 may include at least two electrode terminals 221, which include at least one positive electrode terminal 221a and at least one negative electrode terminal 221b. Each electrode terminal 221 is used to electrically connect with a corresponding tab 232. For example, each electrode terminal 221 can be electrically connected to a corresponding tab 232 through a connecting member. For example, the positive tab 232a of the electrode assembly 23 can be connected to the positive electrode terminal 221a through one connecting member, and the negative tab 232b of the electrode assembly 23 can be connected to the negative electrode terminal 221b through another connecting member.

[0111] At least two electrode terminals 221 of the battery cell 20 can be disposed on the same wall or different walls of the battery cell 20. For example, the position of the electrode terminals 221 can be set according to the position of the tabs 232 of the electrode assembly 23. For example, as shown in Figures 3 to 7, the embodiments of this application mainly take the battery cell 20 as having two electrode terminals 221 with opposite polarities, and the two electrode terminals 221 being disposed on the end cap 22 of the battery cell 20 as an example.

[0112] In some embodiments of this application, the battery cell 20 may also be provided with other components. For example, the battery cell 20 may also be provided with a pressure relief mechanism 222, which is an element or component that is actuated when the internal pressure or temperature of the battery cell 20 reaches a predetermined threshold to release the internal pressure or temperature.

[0113] It should be understood that the hardness in the embodiments of this application refers to the material's ability to resist localized deformation, particularly plastic deformation, indentation, or scratches. The hardness in the embodiments of this application can be tested in various ways; for example, this application mainly uses the Vickers hardness test method. Specifically, when measuring the hardness of any region of the first region 213 or the second region 214 of the shell 21, a region of 15mm*10mm in size perpendicular to the thickness direction of that region of the shell 21 is taken as a sample. The sample is immersed in a resin, and after the resin cures, the cut surfaces of the sample are ground, polished, and etched to make the resin surface smooth. The sample embedded in the resin is placed under a Vickers hardness tester, and the hardness at different points is measured. In one possible implementation, for measuring the hardness of at least a portion of the first region 213 or at least a portion of the second region 214, the hardness of any one point in that portion of the region can be measured as the hardness value of that portion of the region, or the hardness of multiple points in that portion of the region can be measured, and the maximum hardness among the multiple points or the average hardness among the multiple points can be taken as the hardness value of that portion of the region. The embodiments of this application are not limited to this.

[0114] It should be understood that, in order to ensure that the hardness of at least a portion of the first region 213 in this embodiment of the application meets the value of H1, the hardness of at least a portion of the first region 213 can be increased in various ways. In some embodiments, the density of the first region 213 is greater than the density of the second region 214, that is, the hardness of the first region 213 can be increased by increasing the density of the first region 213. Specifically, after welding the housing 21 to the end cap 22, at least a portion of the heat-affected zone 215 can be processed to increase the density of the first region 213. For example, the density can be increased by rolling treatment, for example, at least the first region 213 within the heat-affected zone 215 can be rolled to increase the density of the first region 213. After the rolling treatment, the density of the first region 213 increases, making the density of the first region 213 greater than the density of the second region 214, and the hardness of the first region 213 can also be increased, so that the hardness of at least a portion of the first region 213 meets the value of hardness H1 in this embodiment of the application. Roll forming is a simple operation that makes it easy to increase the hardness of the first region 213.

[0115] In some embodiments, after the first region 213 is rolled, the hardness value of the first region 213 is more uniformly distributed. Therefore, the rolling process can increase the hardness of all or almost all regions of the first region 213. Accordingly, the hardness H1 of at least some regions of the first region 213 in this embodiment can refer to setting the average hardness of all or almost all regions of the first region 213 to a value that satisfies the hardness H1 of this embodiment, but this embodiment is not limited to this.

[0116] In some embodiments, the hardness of the surface of the first region 213 away from the interior of the battery cell 20 is greater than the hardness of the surface of the first region 213 facing the interior of the battery cell 20, meaning that the hardness of only a local area of ​​the first region 213 can be increased. Specifically, after welding the housing 21 to the end cap 22, at least a portion of the heat-affected zone 215 can be treated to increase the hardness of the local area. For example, laser treatment can be used, for instance, to laser treat at least the first region 213 within the heat-affected zone 215 to increase the hardness of the first region 213. In some embodiments, laser treatment can typically be performed from the outer surface of the first region 213 away from the interior of the battery cell 20. Correspondingly, the increase in hardness of the outer surface of the first region 213 will be greater than the increase in hardness of the inner surface of the first region 213 facing the interior of the battery cell 20. That is, after laser treatment, the hardness of the outer surface of the first region 213 is typically greater than the hardness of the inner surface of the first region 213. Laser treatment is simple to operate and can effectively increase the hardness of the first region 213.

[0117] In some embodiments, after the first region 213 is laser-processed, the hardness of the outer surface of the first region 213 is generally greater than the hardness of the inner surface of the first region 213. Therefore, the hardness H1 of at least a portion of the first region 213 in this embodiment can refer to: setting the hardness of at least a portion of the outer surface of the first region 213 to meet the value of hardness H1 in this embodiment, while the inner surface of the first region 213, which has a relatively lower hardness, can meet or be slightly lower than the value of hardness H1 in this embodiment, so as to reduce the difficulty of operation and improve the processing efficiency.

[0118] It should be understood that the first region 213 in the embodiments of this application may undergo only roll forming or only laser processing, or both roll forming and laser processing, to further improve the hardness of the first region 213. In some embodiments, the hardness of the first region 213 in the embodiments of this application may also be increased by other means. For example, the hardness of the first region 213 may also be increased by high-frequency welding. In some embodiments, at least two of a variety of methods such as high-frequency welding, roll forming, and laser hardening may be combined to improve the hardness of the first region 213.

[0119] It should be understood that the materials of the housing 21 and end cap 22 in this embodiment can be set according to actual application. For example, the material of the housing 21 in this embodiment can include one or more materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 22 can also be one or more materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 22 can be the same as or different from that of the housing 21; the materials of different walls of the housing 21 can also be the same or different.

[0120] In some embodiments, the housing 21 is made of aluminum to facilitate processing and reduce costs. Using aluminum for the housing 21 makes it easier to meet the hardness values ​​H1 and H2 of the embodiments of this application, thereby improving the structural stability and reliability of the housing 21.

[0121] In some embodiments, the housing 21 is made of a tri-series aluminum alloy, which is low in material cost, easy to process, and can effectively improve the processing efficiency of the housing 21. For example, the housing 21 may specifically be made of 3003 or 3004 aluminum alloy, but the embodiments of this application are not limited thereto.

[0122] This application also provides a battery device 10, including the battery cell 20 provided in any of the above embodiments.

[0123] In some embodiments, the battery device 10 includes a plurality of battery cells arranged along a second direction, wherein the battery cells located at both ends of the second direction are the battery cells 20 of this application embodiment. For a row of battery cells arranged along the second direction within the battery device 10, each battery cell will expand during use. Due to mutual compression and fixation, the deformation of the battery cells located at both ends of the second direction is greater than that of other battery cells. Therefore, by at least setting the battery cells at both ends of the second direction to be the battery cells 20 of this application embodiment, the hardness of at least a portion of the first region 213 of the shell of the battery cells 20 at both ends is increased, which can better resist deformation, reduce the risk of localized cracking of the battery cells 20 within the battery device 10, and thereby improve the reliability and stability of the battery device 10.

[0124] This application also provides an electrical device, including the battery device 10 provided in any of the above embodiments, the battery device 10 being used to provide electrical energy to the electrical device.

[0125] Figure 8 illustrates a processing method 800 for a battery cell 20 provided in an embodiment of this application. As shown in Figure 8, the processing method 800 includes at least the following:

[0126] 801. Provide a battery cell 20, the battery cell 20 including a housing 21, an electrode assembly 23 and an end cap 22, the housing 21 forming a receiving cavity 212 with an opening 211, the electrode assembly 23 being received in the receiving cavity 212, the end cap 22 being welded to the housing 21 and covering the opening 211, a weld 24 being formed at the connection between the end cap 22 and the housing 21, the housing 21 including a first region 213 near the weld 24; 802. Harden the first region 213, the hardness of at least a portion of the first region 213 after the hardening treatment being H1, H1 satisfying: 35HV≤H1≤60HV, the first region 213 being a region in the housing 21 between 0.1mm and 0.3mm from the edge of the weld 24.

[0127] In some embodiments, hardening the first region 213 includes: rolling the first region 213.

[0128] In some embodiments, hardening the first region 213 includes: laser processing the first region 213.

[0129] In some embodiments, the housing 21 further includes a second region 214 away from the weld 24, at least a portion of the second region 214 having a hardness of H2, where H1 and H2 satisfy: H2-H1≤15HV, and the second region 214 is a region in the housing 21 between 5.0 mm and 6.0 mm from the edge of the weld 24.

[0130] In some embodiments, the material of the housing 21 includes aluminum.

[0131] In some embodiments, the housing 21 is made of tri-aluminum alloy.

[0132] It should be understood that the processing method 800 of this application embodiment can be used to process the battery cell 20 of this application embodiment. For example, the housing 21 and end cap 22 in steps 801 and 802 have been described in detail in the above embodiments and will not be repeated here.

[0133] According to some embodiments of this application, referring to Figures 3 to 8, this application provides a battery cell 20, which includes: a housing 21 forming a receiving cavity 212 with an opening 211; an electrode assembly 23 housed in the receiving cavity 212; an end cap 22 welded to the housing 21 and covering the opening 211, wherein a weld 24 is formed at the connection between the end cap 22 and the housing 21; the housing 21 includes a first region 213 near the weld 24, wherein at least a portion of the first region 213 has a hardness of H1, wherein H1 satisfies: 35HV≤H1≤60HV, and the first region 213 is a region in the housing 21 between 0.1 mm and 0.3 mm from the edge of the weld 24. The housing 21 also includes a second region 214 away from the weld 24, at least a portion of which has a hardness of H2, where H1 and H2 satisfy: H2-H1≤15HV. The second region 214 is a region within the housing 21 located 5.0 mm to 6.0 mm from the edge of the weld 24. In some embodiments, the first region 213 is a roll-formed region, and its density is greater than that of the second region 214. In some embodiments, the first region 213 is a laser-processed region, and the hardness of the surface of the first region 213 away from the interior of the battery cell 20 is greater than the hardness of the surface of the first region 213 facing the interior of the battery cell 20. In some embodiments, the material of the housing 21 includes aluminum. In some embodiments, the material of the housing 21 is a tri-aluminum alloy. In some embodiments, the electrode assembly 23 includes multiple layers of electrodes stacked along a first direction, and the housing 21 includes a first wall 217 and a second wall 218 perpendicular to the first direction and disposed opposite to each other, with the first region 213 located on the first wall 217 and / or the second wall 218. In some embodiments, the first region 213 surrounds the housing 21.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This 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: The shell (21) forms a receiving cavity (212) with an opening (211); Electrode assembly (23) is housed in the receiving cavity (212); End cap (22), which is welded to the housing (21) and covers the opening (211), and a weld (24) is formed at the connection between the end cap (22) and the housing (21); The housing (21) includes a first region (213) near the weld (24), at least a portion of the first region (213) having a hardness of H1, where H1 satisfies: 35HV≤H1≤60HV, and the first region (213) is a region in the housing (21) between 0.1 mm and 0.3 mm from the edge of the weld (24).

2. The battery cell according to claim 1, characterized in that, The housing (21) further includes a second region (214) away from the weld (24), at least a portion of the second region (214) having a hardness of H2, where H1 and H2 satisfy: H2-H1≤15HV, and the second region (214) is a region in the housing (21) between 5.0 mm and 6.0 mm from the edge of the weld (24).

3. The battery cell according to claim 2, characterized in that, H1 and H2 satisfy: H2-H1≤10HV.

4. The battery cell according to claim 2 or 3, characterized in that, The thickness of at least a portion of the second region (214) ranges from [0.4 mm, 0.7 mm], and H2 satisfies: 45HV≤H2≤75HV.

5. The battery cell according to any one of claims 2 to 4, characterized in that, The density of the first region (213) is greater than the density of the second region (214).

6. The battery cell according to any one of claims 1 to 5, characterized in that, The surface of the first region (213) away from the interior of the battery cell has a higher hardness than the surface of the first region (213) facing the interior of the battery cell.

7. The battery cell according to any one of claims 1 to 6, characterized in that, H1 satisfies: H1≥40HV.

8. The battery cell according to any one of claims 1 to 7, characterized in that, The material of the housing (21) includes aluminum.

9. The battery cell according to claim 8, characterized in that, The material of the shell (21) is a tri-series aluminum alloy.

10. The battery cell according to any one of claims 1 to 9, characterized in that, The electrode assembly (23) is a stacked structure, and the electrode assembly (23) includes a plurality of positive electrode plates and a plurality of negative electrode plates. The plurality of positive electrode plates and the plurality of negative electrode plates are stacked along a first direction. The housing (21) includes a first wall (217) and a second wall (218) that are perpendicular to the first direction and arranged opposite to each other. The first region (213) is located on the first wall (217) and / or the second wall (218).

11. The battery cell according to claim 10, characterized in that, The number of the plurality of negative electrode plates is greater than the number of the plurality of positive electrode plates, and a positive electrode plate is disposed between two adjacent negative electrode plates.

12. The battery cell according to claim 10 or 11, characterized in that, Each of the plurality of negative electrode plates is provided with a negative electrode tab (232b); and / or, each of the plurality of positive electrode plates is provided with a positive electrode tab (232a).

13. The battery cell according to any one of claims 1 to 12, characterized in that, The first region (213) is disposed around the housing (21).

14. A battery device, characterized in that, include: The battery cell as described in any one of claims 1 to 13.

15. The battery device according to claim 14, characterized in that, The battery device includes a plurality of battery cells arranged along a second direction, wherein the battery cells located at both ends of the second direction are battery cells as described in any one of claims 1 to 13.

16. An electrical appliance, characterized in that, include: The battery device as claimed in claim 14 or 15, wherein the battery device is used to provide electrical energy to the electrical device.

17. A method for processing a single battery cell, characterized in that, include: A battery cell is provided, the battery cell including a housing (21), an electrode assembly (23) and an end cap (22), the housing (21) forming a receiving cavity (212) with an opening (211), the electrode assembly (23) being received in the receiving cavity (212), the end cap (22) being welded to the housing (21) and covering the opening (211), a weld (24) being formed at the connection between the end cap (22) and the housing (21), and the housing (21) including a first region (213) near the weld (24); The first region (213) is hardened, and at least a portion of the first region (213) after the hardening treatment has a hardness of H1, where H1 satisfies: 35HV≤H1≤60HV. The first region (213) is the area in the shell (21) between 0.1mm and 0.3mm from the edge of the weld (24).

18. The processing method according to claim 17, characterized in that, The hardening process on the first region (213) includes: The first region (213) is subjected to roll forming.

19. The processing method according to claim 17 or 18, characterized in that, The hardening process on the first region (213) includes: The first region (213) is subjected to laser processing.

20. The processing method according to any one of claims 17 to 19, characterized in that, The housing (21) further includes a second region (214) away from the weld (24), at least a portion of the second region (214) having a hardness of H2, where H1 and H2 satisfy: H2-H1≤15HV, and the second region (214) is a region in the housing (21) between 5.0 mm and 6.0 mm from the edge of the weld (24).

21. The processing method according to any one of claims 17 to 20, characterized in that, The material of the housing (21) includes aluminum.

22. The processing method according to claim 21, characterized in that, The material of the shell (21) is a tri-series aluminum alloy.

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