Connection member, battery cell, battery, and electric device

Abstract

The application discloses a connecting member, a battery monomer, a battery and an electric device. The connecting member is used for realizing electrical connection between an electrode terminal and a tab of a battery monomer. The connecting member comprises a main body part and an electrode terminal welding part connected to the main body part. The main body part is used for being connected to the tab, and the electrode terminal welding part is used for being welded to the electrode terminal. The hardness of the electrode terminal welding part is greater than the hardness of the main body part. The application can improve the service life of the battery monomer.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a connecting member, a battery cell, a battery, and an electrical device. Background Technology

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] In the development of battery technology, improving the lifespan of individual battery cells is an important research direction. Summary of the Invention

[0004] This application provides a connecting member, a battery cell, a battery, and an electrical device that can improve the service life of the battery cell.

[0005] In a first aspect, this application provides a connecting member for realizing the electrical connection between the electrode terminal and the tab of a battery cell. The connecting member includes a main body and an electrode terminal welding part connected to the main body. The main body is used to connect with the tab, and the electrode terminal welding part is used to weld with the electrode terminal. The hardness of the electrode terminal welding part is greater than the hardness of the main body.

[0006] In this embodiment, the hardness of the electrode terminal weld portion is greater than that of the main body. Under the premise that the hardness of the main body meets the requirements, increasing the hardness of the electrode terminal weld portion can increase its resistance to deformation during transportation and assembly. Smaller deformation can increase the tightness of the electrode terminal weld portion and the electrode terminal, thereby improving the welding reliability of the electrode terminal and the connecting component, and thus improving the service life of the battery cell.

[0007] In some embodiments, the hardness of the main body is H, and the hardness of the electrode terminal welding part is H1, wherein H1 and H satisfy: 1.05≤H1 / H≤3.

[0008] Limiting the H1 / H value to less than or equal to 3 reduces internal stress during welding of the electrode terminal weld joint, thereby reducing crack formation and improving weld quality. Limiting the H1 / H value to greater than or equal to 1.05 further improves the resistance of the electrode terminal weld joint to deformation, enhances welding performance, and improves the stability and safety of the battery cell.

[0009] In some implementations, H1 and H satisfy: 1.05 ≤ H1 / H ≤ 2. Further limiting the value of H1 / H to less than or equal to 2 further reduces the internal stress generated during welding, thereby further reducing crack formation and improving weld quality.

[0010] In some implementations, H satisfies: 20 kgf / mm 2 ≤H≤70kgf / mm 2 The hardness of the main body is limited to less than or equal to 70 kgf / mm². 2 To reduce cracking and improve weld quality, the hardness of the main body is limited to greater than or equal to 20 kgf / mm². 2 This is to increase the strength of the main body, making it less prone to deformation and improving the quality of welding.

[0011] In some implementations, H1 satisfies: 20 kgf / mm 2 2 The hardness of the electrode terminal weld joint is limited to less than or equal to 210 kgf / mm². 2 This reduces internal stress during welding, minimizes crack formation, and improves welding quality. The hardness of the electrode terminal weld area is limited to greater than 20 kgf / mm². 2 This is to improve the strength of the electrode terminal weld, making it less prone to deformation and improving the quality of the weld.

[0012] In some embodiments, the thickness of the electrode terminal welding portion is less than the thickness of the main body portion.

[0013] When the hardness of the electrode terminal welded part is greater than that of the main body, the internal stress during welding of the electrode terminal welded part is greater. Therefore, reducing the thickness of the electrode terminal welded part relative to the main body reduces the welding power, thereby reducing the internal stress during welding, reducing the generation of cracks, and improving the welding quality.

[0014] In some embodiments, the electrode terminal welding portion has multiple grooves on the side opposite to the electrode terminal.

[0015] By incorporating grooves, the thickness of localized areas in the electrode terminal welding region can be reduced, welding power lowered, internal stress reduced, and welding performance improved, thereby enhancing the stability and safety of the battery cell. Simultaneously, the grooves increase the surface roughness of the electrode terminal welding region away from the electrode terminal, further improving welding quality.

[0016] In some embodiments, the electrode terminal welding portion includes a body region and an embossed region, with a groove recessed from the body region away from the surface of the electrode terminal, and the embossed region corresponding to the bottom wall of the groove; the hardness of the embossed region is greater than the hardness of the body region.

[0017] The hardness of the embossed area is greater than that of the body area. This means that thinning the embossed area increases the resistance of the groove bottom wall to deformation and improves the welding quality.

[0018] In some implementations, the depth of the groove is 0.03mm-0.2mm.​

[0019] Limiting the depth of the groove to less than or equal to 0.2 mm reduces the possibility of weld penetration through the bottom wall of the groove. Limiting the depth of groove 312a to greater than or equal to 0.03 mm significantly reduces the thickness of the bottom wall, lowers the welding power, thereby reducing internal stress during welding, reducing crack formation, and improving weld quality.

[0020] In some embodiments, the main body has a first surface and a second surface disposed opposite to each other, the second surface facing the electrode terminal; the connecting member includes a recess that is recessed relative to the first surface, and the electrode terminal welding portion is located at the bottom of the recess.

[0021] In some embodiments, the connecting member further includes a connecting portion that protrudes from the second surface and connects the main body portion and the electrode terminal welding portion; the connecting portion and the electrode terminal welding portion form a recess.

[0022] By providing a connecting part, the electrode terminal welding part and the main body part are offset in the thickness direction of the connecting member. Therefore, when the connecting member is installed in the battery cell, the electrode terminal welding part can be brought closer to the electrode terminal, which facilitates the connection between the two.

[0023] In some embodiments, the included angle between the connecting part and the main body is in the range of (91°, 130°).

[0024] The draft angle is limited to greater than 91° to facilitate demolding; the draft angle is limited to less than or equal to 130° to reduce processing difficulty.

[0025] In some embodiments, the ratio of the thickness of the connecting portion to the thickness of the main body is greater than or equal to 4 / 5. This is to prevent the connecting member structure from becoming unstable if the thickness of the connecting portion is too small.

[0026] In some embodiments, the thickness H31 of the electrode terminal welding portion and the thickness H33 of the main body portion satisfy: 5%≤(H33-H31) / H33≤65%.

[0027] The value of (H33-H31) / H33 is limited to less than or equal to 65% to reduce the possibility of the electrode terminal weld being melted through; the value of (H33-H31) / H33 is limited to greater than or equal to 5% to effectively reduce the internal stress of the weld, reduce cracks, and improve the weld quality.

[0028] In some embodiments, the area of ​​the surface of the electrode terminal welding part facing the electrode terminal is S1, and the area of ​​the surface of the connecting member facing the electrode terminal is S2, wherein S1 and S2 satisfy: 1 / 50≤S1 / S2≤3 / 5.

[0029] Limiting the value of S1 / S2 to greater than or equal to 1 / 50 effectively solves the problem of easy deformation; limiting the value of S1 / S2 to less than or equal to 3 / 5 reduces the difficulty of processing.

[0030] Secondly, this application provides a battery cell including electrode terminals, an electrode assembly, and a connecting member provided in any embodiment of the first aspect. The electrode assembly includes tabs, and the connecting member is used to realize the electrical connection between the electrode terminals and the tabs.

[0031] Thirdly, this application provides a battery including a plurality of battery cells, wherein the battery cells include the connecting member provided in any embodiment of the first aspect.

[0032] Fourthly, this application provides an electrical device including a battery, the battery including a connecting member provided in any embodiment of the first aspect. Attached Figure Description

[0033] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0034] Figure 1 This is a schematic diagram of the structure of a vehicle according to one embodiment of this application;

[0035] Figure 2 This is a schematic diagram of the structure of a battery according to one embodiment of this application;

[0036] Figure 3 This is an exploded structural diagram of a battery cell according to an embodiment of this application;

[0037] Figure 4 This is a three-dimensional structural diagram of a connecting member according to an embodiment of this application;

[0038] Figure 5 for Figure 4 A top view of the connecting components shown;

[0039] Figure 6 for Figure 5 A schematic cross-sectional view of the connecting member along the A-A' direction;

[0040] Figure 7 for Figure 4 A side view of the connecting component shown;

[0041] Figure 8 This is an exploded structural diagram of a battery cell according to another embodiment of this application;

[0042] Figure 9 This is a schematic diagram of the structure of a connecting member according to another embodiment of this application;

[0043] Figure 10This is a top view of a connecting member according to another embodiment of this application;

[0044] Figure 11 for Figure 9 A side view of the connecting component shown;

[0045] Figure 12 This is an exploded structural diagram of a battery cell according to another embodiment of this application;

[0046] Figure 13 This is a schematic diagram of the structure of a connecting member according to another embodiment of this application;

[0047] Figure 14 This is a schematic diagram of the structure of a connecting member according to another embodiment of this application;

[0048] Figure 15 This is a top view of a connecting member according to another embodiment of this application;

[0049] Figure 16 for Figure 15 A schematic diagram of the cross-section of the connecting member along the B-B' direction is shown.

[0050] Figure 17 This is a schematic diagram of the structure of a connecting member according to another embodiment of this application;

[0051] Figure 18 This is a top view of the connecting member according to another embodiment of this application;

[0052] Figure 19 for Figure 18 The diagram shows a cross-sectional view of the connecting member along the C-C' direction.

[0053] The accompanying drawings are not drawn to scale.

[0054] The reference numerals in the accompanying drawings for the specific embodiments are as follows:

[0055] 1. Vehicle; 10. Battery; 11. Housing; 111. First housing section; 112. Second housing section; 20. Battery cell; 21. Casing; 211. Shell; 2111. Blue film; 212. Cover plate; 213. Pressure relief mechanism; 214. Electrode terminal; 214a. Positive electrode terminal; 214b. Negative electrode terminal; 22. Electrode assembly; 221. Main body; 222. Tab; 222a. Positive tab; 222b. Negative tab 200. Electrode tab; 30. Battery module; 31. Connecting component; 31. Electrode terminal welding part; 311. Body area; 312. Embossed area; 312a. Groove; 32. Connecting part; 33. Main body; 331. Electrode tab welding area; 332. Notch; 333. Chamfered structure; 334. First surface; 335. Second surface; 336. Recess; 40. Motor; 50. Controller; X. First direction; Y. Second direction; Z. Third direction. Detailed Implementation

[0056] 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 and completely 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.

[0057] 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.

[0058] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] In this application, "multiple" means two or more (including two).

[0063] In this application, the battery cell may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application are not limited to these. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited to these. Battery cells are generally divided into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and the embodiments of this application are not limited to these.

[0064] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack. A battery generally includes a housing for encapsulating one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0065] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrodes. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, and the uncoated positive current collector protrudes beyond the coated one, serving as the positive electrode tab. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector, and the uncoated negative current collector protrudes beyond the coated one, serving as the negative electrode tab. The negative electrode current collector can be made of copper, and the negative electrode active material can be carbon or silicon, etc. To ensure that a large current can pass through without melting, there are multiple positive electrode tabs stacked together, and there are multiple negative electrode tabs stacked together. The separator can be made of polypropylene (PP) or polyethylene (PE), etc. Furthermore, the electrode assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited to these.

[0066] A battery cell includes an electrode assembly, an electrolyte, a housing containing the electrode assembly and electrolyte, and a cover plate mounted on the housing. The cover plate is typically fitted with electrode terminals for inputting or outputting electrical energy. During battery cell assembly, the connection between the electrode assembly and the electrode terminals on the cover plate is generally indirect through connecting members, i.e., the connecting members are electrically connected to the electrode assembly and the electrode terminals respectively by welding.

[0067] The inventors discovered that connecting components are prone to deformation during transportation and assembly, and the deformation of connecting components has a significant impact on the subsequent welding effect, especially the part of the connecting component that is welded to the electrode terminals. The deformation of this part has a great impact on the welding effect, which will reduce the welding reliability of the electrode terminals and connecting components and reduce the service life of the battery cells.

[0068] In view of this, this application provides a technical solution that increases the hardness of the part of the connecting member that is welded to the electrode terminal to be greater than the hardness of the part of the connecting member that is welded to the electrode assembly. Thus, while the hardness of the part of the connecting member that is welded to the electrode assembly meets the requirements, the part of the connecting member that is welded to the electrode terminal has greater hardness, thereby having stronger resistance to deformation. The smaller deformation increases the tightness of the fit between the electrode terminal and the connecting member, thereby improving the welding reliability of the electrode terminal and the connecting member and increasing the service life of the battery cell.

[0069] The battery cells described in the embodiments of this application are applicable to batteries and electrical devices that use battery cells.

[0070] Electrical devices can include 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. This application does not impose any special limitations on the above-mentioned electrical devices.

[0071] The technical solutions described in this application are applicable to various battery-powered electrical devices. These 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. This application does not impose any special limitations on the aforementioned electrical devices.

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

[0073] Figure 1 This is a schematic diagram of the structure of a vehicle according to one embodiment of this application.

[0074] like Figure 1As shown, vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A motor 40, a controller 50, and a battery 10 can be installed inside vehicle 1. The controller 50 controls the battery 10 to supply power to the motor 40. For example, the battery 10 can be installed at the bottom, front, or rear of vehicle 1. The battery 10 can be used to power vehicle 1; for example, it can serve as the operating power source for the vehicle 1's electrical system, such as meeting the power requirements for starting, navigation, and operation. In another embodiment of this application, the battery 10 can not only serve as the operating power source for vehicle 1 but also as the driving power source, replacing or partially replacing gasoline or natural gas to provide driving power to vehicle 1.

[0075] To meet diverse power demands, a battery can comprise multiple individual battery cells, which can be connected in series, parallel, or a combination of both. A battery can also be referred to as a battery pack. In some embodiments, multiple battery cells can first be connected in series, parallel, or a combination of both to form a battery module, and then multiple battery modules can be connected in series, parallel, or a combination of both to form a battery. In other words, multiple battery cells can be directly assembled into a battery, or they can first be assembled into battery modules, and then the battery modules can be assembled into a battery.

[0076] Figure 2 This is a schematic diagram of the structure of a battery according to an embodiment of this application.

[0077] like Figure 2 As shown, the battery 10 may include at least one battery module 200. The battery module 200 includes a plurality of battery cells 20. The battery 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 This illustration shows a possible implementation of the housing 11 according to an embodiment of this application. The housing 11 may include two parts, referred to herein as a first housing portion 111 and a second housing portion 112, which are fastened together. The shapes of the first housing portion 111 and the second housing portion 112 can be determined according to the shape of the battery module 200 assembly, and at least one of the first housing portion 111 and the second housing portion 112 has an opening. For example, as... Figure 2 As shown, both the first box section 111 and the second box section 112 can be hollow cuboids and each has only one open side. The openings of the first box section 111 and the second box section 112 are arranged opposite to each other, and the first box section 111 and the second box section 112 are interlocked to form a box 11 with a closed cavity.

[0078] For example, unlike Figure 2As shown, one of the first housing portion 111 and the second housing portion 112 may be a hollow cuboid with an opening, while the other may be plate-shaped to cover the opening. For example, if the second housing portion 112 is a hollow cuboid with only one open side, and the first housing portion 111 is plate-shaped, then the first housing portion 111 covers the opening of the second housing portion 112 to form a housing 11 with a closed chamber, which can be used to 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 first housing portion 111 and the second housing portion 112 being fastened together.

[0079] In some embodiments, the battery 10 may also include other structures, which will not be described in detail here. For example, the battery 10 may also include a busbar component for realizing electrical connections between multiple battery cells 20, such as parallel, series, or mixed connections. Specifically, the busbar component can realize electrical connections between battery cells 20 by connecting the electrode terminals of the battery cells 20. Further, the busbar component can be fixed to the electrode terminals of the battery cells 20 by welding. The electrical energy of the multiple battery cells 20 can be further led out through the housing 11 via a conductive mechanism.

[0080] The number of battery cells 20 in the battery module 200 can be set to any value according to different power requirements. Multiple battery cells 20 can be connected in series, parallel, or mixed connection to achieve a larger capacity or power. Since each battery 10 may contain a large number of battery cells 20, for ease of installation, the battery cells 20 are grouped, and each group of battery cells 20 constitutes a battery module 200. The number of battery cells 20 in a battery module 200 is unlimited and can be set according to requirements. A battery may include multiple battery modules 200, which can be connected in series, parallel, or mixed connection.

[0081] Figure 3 This is an exploded structural diagram of a battery cell according to an embodiment of this application.

[0082] like Figure 3 As shown, the battery cell 20 in this embodiment may include one or more electrode assemblies 22 and a housing 21 for accommodating the electrode assemblies 22.

[0083] The outer casing 21 in this embodiment can be a polyhedral structure. Specifically, the outer casing 21 may include a housing 211 and a cover plate 212. The housing 211 may be a hollow structure with an opening at at least one end, and the shape of the cover plate 212 may be adapted to the shape of the housing 211. The cover plate 212 is used to cover the opening of the housing 211 so that the housing 21 isolates the internal environment of the battery cell 20 from the external environment. If the housing 211 is a hollow structure with an opening at one end, one cover plate 212 may be provided; if the housing 211 is a hollow structure with openings at opposite ends, two cover plates 212 may be provided, with the two cover plates 212 respectively covering the openings at both ends of the housing 211.

[0084] The shell 211 in this embodiment can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The cover plate 212 can also be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the cover plate 212 can be the same as or different from that of the shell 211.

[0085] The outer shell 21 in this embodiment can be of various shapes, such as a cylinder, a cuboid, etc. The shapes of the shell 211 and the cover plate 212 are mutually compatible, for example, as shown in... Figure 3 As shown, the shell 211 can be a cuboid structure, and the cover plate 212 is a rectangular plate structure adapted to the shell 211.

[0086] For ease of explanation, this application uses a cuboid as an example for the outer shell 21. Specifically, as... Figure 3 As shown, the outer casing 21 includes: a housing 211, which is a hollow structure with one end open; and a cover plate 212, which is used to cover the opening of the housing 211 to form a closed cavity for placing the electrode assembly 22.

[0087] Optionally, the housing 21 in this embodiment may be provided with multiple components. For example, such as Figure 3 As shown, the battery cell 20 may also include a pressure relief mechanism 213, which can be disposed on any wall of the housing 21, for example, Figure 3 Taking the pressure relief mechanism 213 located on the cover plate 212 as an example, specifically, the pressure relief mechanism 213 is actuated to release the internal pressure or temperature when the internal pressure or temperature of the battery cell 20 reaches a threshold.

[0088] In addition, such as Figure 3 As shown, an injection hole 215 can also be provided on any wall of the outer casing 21 of the battery cell 20, for example, Figure 3 Taking the injection hole 215 located on the cover plate 212 as an example, the injection hole 215 is used to inject electrolyte into the interior of the outer casing 21.

[0089] Optionally, such as Figure 3 As shown, the outer surface of the housing 21 may also be provided with a blue film 2111. For example, it may be provided on the outer surface of the housing 211 to achieve the function of insulation and protection of the battery cell 20, but the embodiments of this application are not limited thereto.

[0090] In this battery cell 20, the housing 211 is used to house the electrode assembly 22, and, depending on actual usage requirements, the electrode assembly 22 within the housing 211 can be one or more. For example, Figure 3 Taking a battery cell 20 comprising two electrode assemblies 22 arranged along a first direction X as an example, the embodiments of this application are not limited thereto. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0091] The electrode assembly 22 in this embodiment is a component in the battery cell 20 where an electrochemical reaction occurs. The electrode assembly 22 can be a cylinder, a cuboid, etc. If the electrode assembly 22 is a cylindrical structure, the housing 211 can also be a cylindrical structure; if the electrode assembly 22 is a cuboid structure, the housing 211 can also be a cuboid structure.

[0092] For any given electrode assembly 22, the electrode assembly 22 may include a tab 222 and a main body portion 221. Specifically, as shown... Figure 3 As shown, the electrode assembly 22 may include at least two tabs 222, which may include a positive tab 222a and a negative tab 222b. The positive tab 222a may be formed by stacking the portion of the positive electrode sheet that is not coated with a positive active material layer, and the negative tab 222b may be formed by stacking the portion of the negative electrode sheet that is not coated with a negative active material layer. The main body portion 221 of the electrode assembly 22 may be formed by stacking or winding the portion of the positive electrode sheet coated with a positive active material layer and the portion of the negative electrode sheet coated with a negative active material layer.

[0093] In this embodiment, the outer casing 21 is further provided with electrode terminals 214, which are used for electrical connection with the electrode assembly 22 to output the electrical energy of the battery cell 20. For example, as Figure 3 As shown, the battery cell 20 may further include at least two electrode terminals 214, which may be disposed on a cover plate 212. The cover plate 212 is typically flat, and the two electrode terminals 214 are fixed to the flat surface of the cover plate 212, namely a positive electrode terminal 214a and a negative electrode terminal 214b. Each electrode terminal 214 is provided with a corresponding connecting member 30, which is located between the cover plate 212 and the electrode assembly 22, and is used to electrically connect the electrode assembly 22 and the electrode terminal 214. Specifically, as shown... Figure 3As shown, the positive electrode tab 222a of the electrode assembly 22 can be connected to the positive electrode terminal 214a through a connecting member 30, and the negative electrode tab 222b of the electrode assembly 22 can be connected to the negative electrode terminal 214b through another connecting member 30.

[0094] Figure 4 This is a three-dimensional structural diagram of a connecting member according to an embodiment of this application. Figure 5 for Figure 4 The diagram shows a top view of the connecting components. Figure 6 for Figure 5 The diagram shows a cross-sectional view of the connecting member along the A-A' direction.

[0095] like Figure 4-6 As shown, the connecting member 30 in this embodiment of the application is used to realize the electrical connection between the electrode terminal 214 of the battery cell 20 and the tab 222. The connecting member 30 includes a main body 33 and an electrode terminal welding part 31 connected to the main body 33. The main body 33 is used to connect with the tab 222, and the electrode terminal welding part 31 is used to weld with the electrode terminal 214. The hardness of the electrode terminal welding part 31 is greater than the hardness of the main body 33.

[0096] In this embodiment, the electrode terminal welding portion 31 and the electrode terminal 214 are connected by welding. Optionally, this welding method can be laser welding.

[0097] In this embodiment, the hardness of the electrode terminal welding portion 31 can be increased by stretching, pressing, or heat treatment to make it greater than the hardness of the main body portion 33.

[0098] In this embodiment, the hardness of the electrode terminal welding portion 31 is greater than that of the main body portion 33. Under the premise that the hardness of the main body portion 33 meets the requirements, increasing the hardness of the electrode terminal welding portion 31 can increase its resistance to deformation during transportation and assembly. Smaller deformation can increase the tightness of the fit between the electrode terminal welding portion 31 and the electrode terminal 214, thereby improving the welding reliability of the electrode terminal 214 and the connecting member 30, and thus improving the service life of the battery cell 20.

[0099] In some embodiments, the electrode terminal welding portion 31 is formed using a tension or pressing connection member.

[0100] Thinning is achieved by stretching or pressing, which is easy to operate and has a low processing cost.

[0101] In some embodiments, the hardness of the main body 33 is H, and the hardness of the electrode terminal welding part 31 is H1, wherein H1 and H satisfy: 1.05≤H1 / H≤3.

[0102] The hardness of the main body 33 in this embodiment is the average hardness of the main body 33, and the hardness of the electrode terminal welding portion 31 is also the average hardness of the electrode terminal welding portion 31. Taking the main body 33 as an example, during measurement, N points can be selected on the main body 33, and the hardness of each of the N points can be measured. Then, the average hardness of the N points is calculated as the hardness of the main body 33. Similarly, the hardness of the electrode terminal welding portion 31 is calculated in the same way, that is, the average hardness of the N points of the electrode terminal welding portion 31 is calculated as the hardness of the electrode terminal welding portion 31. For example, N is 10.

[0103] This application does not limit the method for measuring hardness. For example, Shore, Rockwell, Brinell, or Vickers methods can be used. It should be understood that the hardness measurement methods for the main body 33 and the electrode terminal welding part 31 should be consistent. For example, when the hardness of the electrode terminal welding part 31 is measured using the Vickers method, the main body 33 should also be measured using the Vickers method.

[0104] The inventors discovered that as the hardness of a material increases, the internal stress during welding also increases accordingly. When the material hardness is excessively high, the internal stress becomes excessive. After cooling and solidification, this excessive internal stress makes the electrode terminal weld portion 31 prone to cracking, thus reducing the reliability of the connection between the electrode terminal weld portion 31 and the electrode terminal 214. In particular, when the hardness of the electrode terminal weld portion 31 is increased using stretching or pressing processes, residual processing stress remains in the electrode terminal weld portion 31. During subsequent welding, this processing stress, combined with the excessive internal stress, makes the electrode terminal weld portion 31 more susceptible to cracking, thus affecting the welding quality, reducing the reliability of the connection between the electrode terminal weld portion 31 and the electrode terminal 214, and shortening the service life of the battery cell 20.

[0105] Provided that the hardness of the main body 33 meets the welding requirements with the tab 222, and taking the hardness of the main body 33 as a benchmark, the greater the hardness of the electrode terminal welding part 31 relative to the main body 33, the stronger its resistance to deformation and the higher the reliability of the connection with the electrode terminal 214. However, when the hardness of the electrode terminal welding part 31 is too high, the internal stress during welding will also be too high, making it more prone to cracking after cooling and solidification, resulting in poorer welding quality. Conversely, if the hardness of the electrode terminal welding part 31 is greater than that of the main body 33, the smaller the hardness of the electrode terminal welding part 31 relative to the main body 33, the less significant the increase in the electrode terminal welding part 31's resistance to deformation. Therefore, this application balances the issues of deformation resistance and cracking of the electrode terminal welding part 31 by limiting the ratio of the hardness of the main body 33 to the hardness of the electrode terminal welding part 31.

[0106] The larger the H1 / H value, the more prone it is to cracking during welding, resulting in poorer weld quality; the smaller the H1 / H value, the less significant the improvement in resistance to deformation.

[0107] Therefore, the value of H1 / H is limited to less than or equal to 3 to reduce the internal stress during welding of the electrode terminal weld portion 31, thereby reducing crack formation and improving welding quality. The value of H1 / H is limited to greater than or equal to 1.05 to further improve the resistance of the electrode terminal weld portion 31 to deformation, improve the welding effect, and enhance the stability and safety of the battery cell 20.

[0108] Optionally, the value of H1 / H can be 1.05, 1.1, 1.3, 1.5, 2, 2.1, 2.2, 2.4, 2.5, 2.6, 2.8 or 3.

[0109] Optionally, the connecting member 30 may be made of copper or aluminum.

[0110] In some embodiments, H1 and H satisfy: 1.05 ≤ H1 / H ≤ 2.

[0111] The value of H1 / H is further limited to less than or equal to 2 to further reduce the internal stress generated during welding, thereby further reducing the generation of cracks during welding and improving welding quality.

[0112] In some embodiments, H satisfies: 20 kgf / mm 2 ≤H≤70kgf / mm 2 .

[0113] The greater the hardness of a material, the greater the internal stress during welding, the easier it is to produce cracks, and the worse the weld quality. The lower the hardness of a material, the weaker its resistance to deformation, the easier it is to deform, resulting in poor weld quality or even melting through.

[0114] Therefore, the hardness of the main body 33 is limited to less than or equal to 70 kgf / mm². 2 To reduce cracking and improve welding quality, the hardness of the main body 33 is limited to greater than or equal to 20 kgf / mm². 2 This is to increase the strength of the main body 33, making it less prone to deformation and improving the quality of welding.

[0115] Optionally, the value of H can be 20 kgf / mm. 2 30kgf / mm 2 40kgf / mm 2 50kgf / mm 2 60kgf / mm 2 Or 70 kgf / mm 2 .

[0116] In some embodiments, H1 satisfies: 20 kgf / mm 2 2 .

[0117] As mentioned above, the greater the hardness of the electrode terminal welding portion 31, the greater the internal stress during welding, and therefore the easier it is to generate cracks during welding, resulting in poorer welding quality. Conversely, the lower the hardness of the electrode terminal welding portion 31, the lower its strength, and the easier it is to deform during welding, or even be welded through.

[0118] Therefore, the hardness of the electrode terminal welding portion 31 is limited to less than or equal to 210 kgf / mm². 2 This reduces internal stress during welding, minimizes crack formation, and improves welding quality. The hardness of the electrode terminal welding portion 31 is limited to greater than 20 kgf / mm². 2 This is to increase the strength of the electrode terminal welding part 31, making it less prone to deformation and improving the welding quality.

[0119] Optionally, the value of H1 can be 30 kgf / mm. 2 50kgf / mm 2 70kgf / mm 2 90kgf / mm 2 Or 120 kgf / mm 2 150kgf / mm 2 170kgf / mm 2 180kgf / mm 2 200kgf / mm 2 Or 210 kgf / mm 2 .

[0120] In some embodiments, the thickness of the electrode terminal welding portion 31 is less than the thickness of the main body portion 33.

[0121] In this embodiment, the thickness H31 of the electrode terminal welding portion 31 can be the thickness of the electrode terminal welding portion 31 along a third direction Z, which is perpendicular to the surface of the electrode terminal welding portion 31 facing the electrode terminal 214, or perpendicular to the surface of the electrode terminal welding portion 31 away from the electrode terminal 214. Similarly, the thickness H33 of the main body portion 33 in this embodiment can also be the thickness of the main body portion 33 along a third direction Z.

[0122] ​The electrode terminal welding portion 31 in this application embodiment can be configured to have uniform thickness in different regions, or it can be configured to have unequal thickness. Specifically, the thickness of different regions of the electrode terminal welding portion 31 is usually set to be equal to facilitate processing. If the thickness of different regions of the electrode terminal welding portion 31 is unequal, for example, if only a local thinning process is performed on the electrode terminal welding portion 31, then the thickness H31 of the electrode terminal welding portion 31 in this application embodiment can represent the maximum, average, or minimum thickness of the electrode terminal welding portion 31. This application embodiment is not limited to this.

[0123] The thicknesses of different regions of the main body portion 33 in this embodiment can also be set to be equal or unequal. Specifically, the thicknesses of different regions of the main body portion 33 are usually set to be equal to facilitate processing. If the thicknesses of different regions of the main body portion 33 are unequal, the calculation method of the thickness H33 of the main body portion 33 in this embodiment should be consistent with that of the electrode terminal welding portion 31. The thickness H33 of the main body portion 33 can also represent the maximum, average, or minimum thickness of the main body portion 33. For example, if the thicknesses of different regions of the electrode terminal welding portion 31 are different, and the thicknesses of different regions of the main body portion 33 are also different, the thickness H31 of the electrode terminal welding portion 31 can be the maximum thickness of the electrode terminal welding portion 31. Correspondingly, the thickness H33 of the main body portion 33 can also be the maximum thickness of the main body portion 33, but this embodiment is not limited to this.

[0124] When the hardness of the electrode terminal welding portion 31 is greater than that of the main body portion 33, the internal stress of the electrode terminal welding portion 31 during welding is greater. Therefore, reducing the thickness of the electrode terminal welding portion 31 relative to the main body portion 33 reduces the welding power during welding, thereby reducing the internal stress during welding, reducing the generation of cracks, and improving the welding quality. In some embodiments, the electrode terminal welding portion 31 has a plurality of grooves 312a on the side opposite to the electrode terminal 214.

[0125] The embodiments of this application do not limit the arrangement of the grooves 312a. Multiple grooves 312a can be arranged in an array or scattered.

[0126] In the embodiments of this application, the dimensions of the multiple grooves 312a may be the same or different, or some of the grooves 312a may have the same dimensions while the remaining parts have different dimensions.

[0127] By setting the groove 312a, the thickness of the local area of ​​the electrode terminal welding portion 31 is reduced, the welding power is lowered, the internal stress of the welding is reduced, and the welding effect is improved, thereby improving the stability and safety of the battery cell 20. At the same time, the setting of the groove 312a can increase the surface roughness of the electrode terminal welding portion 31 away from the electrode terminal 214, thereby improving the welding quality.

[0128] In some embodiments, the electrode terminal welding portion includes a body region 311 and an embossed region 312. A groove 312a is recessed from the surface of the body region 311 away from the electrode terminal 214. The embossed region 312 corresponds to the bottom wall of the groove 312a. The hardness of the embossed region 312 is greater than the hardness of the body region 311.

[0129] In this embodiment, the hardness of the embossed area 312 is the average hardness of the embossed area 312, and the hardness of the body area 311 is also the average hardness of the body area 311. Taking the measurement of the hardness of the embossed area 312 as an example, during measurement, the bottom walls of N grooves 312a in the embossed area 312 can be selected, and the hardness of the bottom walls of the N grooves 312a can be measured respectively. Then, the average hardness of the bottom walls of the N grooves 312a can be calculated as the hardness of the embossed area 312. When measuring the hardness of the body area 311, N points can be selected in the body area 311, and the average hardness of the N points in the body area 311 can be calculated as the hardness of the body area 311. Here, N is a positive integer. For example, N is 8, 10, or 12.

[0130] This application does not limit the method for measuring hardness. For example, Shore, Rockwell, Brinell, or Vickers methods can be used. It should be understood that the method for measuring the hardness of the embossed area 312 and the body area 311 should be consistent. For example, when the hardness of the embossed area 312 is measured using the Vickers method, the hardness of the body area 311 should also be measured using the Vickers method.

[0131] The hardness of the embossed area 312 is greater than that of the body area 311. This means that after thinning, the bottom wall of the groove 312a has increased resistance to deformation, thus improving the welding quality.

[0132] Optionally, the stamped area 312 is formed by pressing.

[0133] In some embodiments, the depth of the groove 312a is 0.03mm-0.2mm.

[0134] In this embodiment, the depth of the embossed area 312 ranges from two values: 0.03 mm and 0.2 mm.

[0135] The greater the depth of groove 312a, the thinner the bottom wall of groove 312a, the lower the welding power, the lower the welding internal stress, and the better the welding quality. However, if the depth of groove 312a is too large, it will result in over-design, which may cause the embossed area 312 to be too thin and welded through. The smaller the depth of groove 312a, the smaller the reduction in the bottom wall thickness of groove 312a, and the less significant the improvement in internal stress problem.

[0136] Therefore, limiting the depth of groove 312a to less than or equal to 0.2 mm can reduce the possibility of weld penetration through the bottom wall of groove 312a. Limiting the depth of groove 312a to greater than or equal to 0.03 mm can significantly reduce the thickness of the bottom wall of groove 312a, reduce welding power, thereby reducing internal stress during welding, reducing crack formation, and improving welding quality.

[0137] In some alternative embodiments, the thickness H31 of the electrode terminal welding portion 31 and the thickness H33 of the main body portion 33 satisfy: 5%≤(H33-H31) / H33≤65%.

[0138] Here, (H33-H31) / H33 characterizes the thinning extent of the electrode terminal weld portion 31 relative to the main body portion 33. A larger value for (H33-H31) / H33 indicates a greater thinning extent of the electrode terminal weld portion 31, resulting in a smaller thickness H31 and lower internal stress during welding. However, if the thickness H31 of the electrode terminal weld portion 31 is too small, it may lead to melting through the electrode terminal weld portion 31 during welding; conversely, if the thinning extent of the electrode terminal weld portion 31 is too small, it will not effectively reduce the internal stress during welding.

[0139] Therefore, the value of (H33-H31) / H33 is limited to less than or equal to 65% to reduce the possibility of the electrode terminal weld 31 being melted through; the value of (H33-H31) / H33 is limited to greater than or equal to 5% to effectively reduce the internal stress of the weld, reduce cracks, and improve the weld quality.

[0140] Optionally, the value of (H33-H31) / H33 can be 5%, 10%, 20%, 30%, 40%, 50%, 60% or 65%.

[0141] For example, the ratio of the thickness H31 of the electrode terminal welding portion 31 to the thickness H33 of the main body portion 33 can be set to be greater than or equal to 1 / 2; as another example, the ratio of the thickness H31 of the electrode terminal welding portion 31 to the thickness H33 of the main body portion 33 can be set to be greater than or equal to 2 / 3.

[0142] In some alternative embodiments, the area of ​​the surface of the electrode terminal welding portion 31 facing the electrode terminal 214 is S1, and the area of ​​the surface of the connecting member 30 facing the electrode terminal is S2, wherein S1 and S2 satisfy: 1 / 50≤S1 / S2≤3 / 5.

[0143] Optionally, considering that the electrode terminal welding portion 31 in this embodiment may have locally increased hardness, the ratio of the area of ​​the surface of the electrode terminal welding portion 31 with increased hardness facing the electrode terminal to the area of ​​the surface of the connecting member 30 facing the electrode terminal can be set to a range of [1 / 50, 3 / 5].

[0144] If the surface area of ​​the electrode terminal welding portion 31 facing the electrode terminal 214 is too small, that is, if the area of ​​increased hardness of the electrode terminal welding portion 31 is too small, for example, if the actual welding area exceeds the area of ​​increased hardness, then the area of ​​increased hardness cannot effectively solve the problem of easy deformation. Conversely, if the surface area of ​​the electrode terminal welding portion 31 facing the electrode terminal 214 is too large, that is, if the area of ​​increased hardness is too large, since the actual welding area is limited, the excessively large area will increase the processing difficulty of the connecting member 30 and reduce production efficiency.

[0145] Limiting the value of S1 / S2 to greater than or equal to 1 / 50 effectively solves the problem of easy deformation; limiting the value of S1 / S2 to less than or equal to 3 / 5 reduces the difficulty of processing.

[0146] In this embodiment, the surface of the electrode terminal welding portion 31 facing the electrode terminal 214 protrudes from, is recessed from, or is flush with the surface of the main body portion 33 facing the electrode terminal 214.

[0147] In some embodiments, the main body 33 has a first surface 334 and a second surface 335 disposed opposite to each other, the second surface 335 facing the electrode terminal 214; the connecting member includes a recess 336, the recess 336 being recessed relative to the first surface 334, and the electrode terminal welding portion 31 being located at the bottom of the recess 336.

[0148] In this embodiment, the recess 336 refers to a recessed space.

[0149] In some embodiments, the connecting member 30 further includes a connecting portion 32, which protrudes from the second surface 335 and connects the main body portion 33 and the electrode terminal welding portion 31; the connecting portion 32 and the electrode terminal welding portion 31 form a recess 336.

[0150] The shape of the connecting part 32 is not limited in the embodiments of this application. For example, it can be a ring, a plate structure or other shapes.

[0151] By providing the connecting part 32, the electrode terminal welding part 31 and the main body part 33 are offset in the thickness direction of the connecting member 30, i.e., the third direction Z. Therefore, when the connecting member 30 is installed in the battery cell 20, the electrode terminal welding part 31 can be closer to the electrode terminal 214, which facilitates the connection between the two.

[0152] Optionally, in this embodiment, the connecting portion 32 is located between the electrode terminal welding portion 31 and the main body portion 33, and the connecting portion 32 can also be thinned. Specifically, the thickness H32 of the connecting portion 32 is less than the thickness H33 of the main body portion 33 to facilitate processing, and at the same time, it can reduce the overall weight of the connecting member 30, thereby reducing the weight of the battery cell 20. The connecting portion 32 can also be treated to increase its hardness, with the hardness of the connecting portion 32 being greater than that of the main body portion 33, to increase its resistance to deformation.

[0153] In this embodiment, the thickness H32 of the connecting portion 32 can be set according to the actual application. For example, the thickness H32 of the connecting portion 32 is greater than the thickness H31 of the electrode terminal welding portion 31, which facilitates processing and ensures the reliability of the connecting portion 32. The hardness of the connecting portion 32 can also be set according to the actual application. For example, the hardness of the connecting portion 32 is less than the hardness of the electrode terminal welding portion 31, which facilitates processing.

[0154] In some alternative embodiments, the ratio of the thickness H32 of the connecting portion 32 to the thickness H33 of the main body portion 33 is greater than or equal to 4 / 5, so as to avoid the connection member 30 structure being unstable when the thickness H32 of the connecting portion 32 is too small.

[0155] The thinning of the electrode terminal welding portion 31 and / or connecting portion 32 in this application embodiment can be achieved in various ways, and the thinning of the electrode terminal welding portion 31 and connecting portion 32 can be achieved in the same or different ways. For example, the thinning of the electrode terminal welding portion 31 and connecting portion 32 can be achieved simultaneously in the same way to improve processing efficiency. For example, the thinning of the electrode terminal welding portion 31 and connecting portion 32 can be achieved by stamping and stretching, or by turning, milling, or upsetting, etc. The embodiments of this application are not limited to these.

[0156] Figure 7 for Figure 4 The diagram shows a side view of the connecting component.

[0157] Optionally, in this embodiment, the connecting portion 32 is used to connect the main body portion 33 and the electrode terminal welding portion 31. The included angle θ between the connecting portion 32 and the main body portion 33 can be set according to actual processing needs. Specifically, as shown... Figures 4 to 7 As shown, considering that a rounded corner is usually provided between the connecting portion 32 and the main body portion 33, and a rounded corner is usually also provided between the connecting portion 32 and the electrode terminal welding portion 31, to facilitate processing, the included angle θ between the connecting portion 32 and the main body portion 33 in this embodiment refers to the included angle between the area of ​​the connecting portion 32 without the rounded corner and the area of ​​the main body portion 33 without the rounded corner.

[0158] In some embodiments, the included angle θ between the connecting portion 32 and the main body portion 33 ranges from 91° to 130°.

[0159] The angle θ between the connecting part 32 and the main body 33 is the draft angle θ during processing. The smaller the draft angle θ, the more difficult it is to demold; conversely, the larger the draft angle θ, the more difficult it is to process.

[0160] Therefore, the draft angle θ is limited to greater than 91° to facilitate demolding; the draft angle θ is limited to less than or equal to 130° to reduce the processing difficulty.

[0161] In some embodiments, the main body 33 includes a tab welding area 331 for welding to a tab 222 to achieve a connection between the connecting member 30 and the tab 222. Specifically, the tab welding area 331 may be at least a portion of the main body 33; and the main body 33 may include one connected tab welding area 331, or it may include multiple non-connected tab welding areas 331. For example, Figure 5 The possible location of the tab welding area 331 is shown, but the embodiments of this application are not limited thereto.

[0162] Optionally, such as Figures 4 to 7 As shown, the relative positions of the tab welding area 331 and the electrode terminal welding portion 31 in this embodiment can be set according to actual applications. For example, the tab welding area 331 is located at the end of the main body 33 away from the electrode terminal welding portion 31 to avoid mutual interference between the tab welding area 331 and the electrode terminal welding portion 31, and also to facilitate processing.

[0163] Optionally, in this embodiment of the application, the electrode welding area 331 and the electrode 222 can be electrically connected by welding, for example, by ultrasonic welding.

[0164] Optionally, such as Figures 4 to 7 As shown, the main body 33 of the connecting member 30 may also have a notch 332. For example, a notch 332 may be provided in the area of ​​the main body 33 away from the electrode terminal welding portion 31 to remove excess material from the main body 33, thereby reducing the weight of the connecting member 30 and thus reducing the weight of the battery cell 20.

[0165] Optionally, such as Figures 4 to 7As shown, the notch 332 of the main body 33 can be U-shaped to facilitate processing. Additionally, the connecting member 30 can also be provided with a chamfered structure 333, which can be used for foolproof installation to facilitate the connection member 30. Optionally, the chamfered structure 333 can be provided at any corner of the connecting member 30, for example, at the edge corner of the U-shaped notch 332, or at other corner locations; the embodiments of this application are not limited to this.

[0166] It should be understood that the shape and position of the electrode terminal welding portion 31 in this application embodiment can be set according to actual application. For example, the shape of the electrode terminal welding portion 31 can be circular, rectangular or triangular to facilitate processing.

[0167] like Figures 4 to 7 As shown, the connecting portion 32 surrounds the electrode terminal welding portion 31, and the connecting portion 32 and the electrode terminal welding portion 31 form a recess 336. The main body portion 33 surrounds the connecting portion 32.

[0168] Alternatively, unlike Figures 4 to 7 The connecting member 30 shown in this application embodiment may also have other configurations for the electrode terminal welding part 31.

[0169] Figure 8 An exploded structural diagram of a battery cell according to another embodiment of this application is shown; Figure 9 This is a schematic diagram of the structure of a connecting member according to another embodiment of this application. For example, the... Figure 9 The connecting member 30 shown can be any connecting member 30 within the battery cell 20; here, it is used as an example. Figure 9 The connecting member 30 shown is Figure 8 Take the right-side connecting member 30 as an example; Figure 10 This is a top view of a connecting member according to another embodiment of this application, namely... Figure 10 The surface of the connecting member 30 facing the electrode assembly 22 is shown; Figure 11 for Figure 9 The diagram shows a side view of the connecting component.

[0170] For example, with Figures 3 to 7 The connecting member 30 shown is similar. Figures 8 to 11 The connecting member 30 shown also includes a recess 336 and a connecting portion 32, with the connecting portion 32 and the electrode terminal welding portion 31 surrounding to form the recess 336.

[0171] But different Figures 3 to 7 The connecting member 30 shown is, for example Figures 8 to 11The electrode terminal welding portion 31 and the main body portion 33 of the connecting member 30 shown are located at opposite ends of the connecting portion 32, which makes it easier to process and avoids mutual interference between the electrode terminal welding portion 31 and the main body portion 33.

[0172] It should be understood that, in the embodiments of this application, the surface of the electrode terminal welding portion 31 facing the electrode terminal 214 protrudes beyond the surface of the main body portion 33 facing the electrode terminal 214, and the surface of the electrode terminal welding portion 31 away from the electrode terminal 214 may also protrude beyond the surface of the main body portion 33 facing the electrode terminal 214; or, unlike this, the surface of the electrode terminal welding portion 31 away from the electrode terminal 214 may also be flush with the surface of the main body portion 33 facing the electrode terminal 214. The embodiments of this application are not limited to this.

[0173] Figures 8 to 11 The remaining description of the connecting member 30 shown applies to Figures 3 to 7 The relevant description of the connecting member 30 shown, for example, Figures 8 to 11 The thickness, hardness, and angle settings of each region of the connecting member 30 are all consistent with... Figures 3 to 7 The connecting member 30 shown is the same, and for the sake of simplicity, it will not be described again here.

[0174] Alternatively, as another embodiment, the surface of the electrode terminal welding portion 31 facing the electrode terminal 214 in this application embodiment may also be recessed into the surface of the main body portion 33 facing the electrode terminal 214. Specifically, Figure 12 This is an exploded structural diagram of a battery cell according to another embodiment of this application; Figure 13 This is a schematic diagram of the structure of a connecting member according to another embodiment of this application. For example, the... Figure 13 The connecting member 30 shown can be any connecting member 30 within the battery cell 20; here, it is used as an example. Figure 13 The connecting member 30 shown is Figure 12 Take the right-side connecting member 30 as an example.

[0175] This embodiment and Figures 8 to 11 The only difference in the connecting member 30 shown is: Figures 8 to 11 The surface of the electrode terminal welding portion 31 of the intermediate connecting member 30 facing the electrode terminal 214 protrudes from the surface of the main body portion 33 facing the electrode terminal 214, and Figure 12 and Figure 13 The surface of the electrode terminal welding portion 31 of the connecting member 30 facing the electrode terminal 214 is recessed into the surface of the main body portion 33 facing the electrode terminal 214, that is, the relative positions of the electrode terminal welding portion 31 and the main body portion 33 are different.

[0176] By setting the surface of the electrode terminal welding portion 31 of the connecting member 30 facing the electrode terminal 214 to be recessed into the surface of the main body portion 33 facing the electrode terminal 214, the space between the main body portion 221 of the electrode assembly 22 and the surface of the electrode terminal 214 facing the main body portion 221 can be utilized more fully. In particular, when the surface of the electrode terminal 214 facing the main body portion 221 protrudes from the surface of the cover plate 212 facing the main body portion 221, setting the surface of the electrode terminal welding portion 31 facing the electrode terminal 214 to be recessed into the surface of the main body portion 33 facing the electrode terminal 214 can improve the space utilization rate inside the battery cell 20.

[0177] Optionally, if the surface of the electrode terminal welding portion 31 of the connecting member 30 facing the electrode terminal 214 is recessed into the surface of the main body portion 33 facing the electrode terminal 214, such as Figure 12 and Figure 13 As shown, the surface of the electrode terminal welding portion 31 away from the electrode terminal 214 may also be recessed into the surface of the main body portion 33 away from the electrode terminal 214; or, unlike this, the surface of the electrode terminal welding portion 31 away from the electrode terminal 214 may also be flush with the surface of the main body portion 33 away from the electrode terminal 214. The embodiments of this application are not limited to this.

[0178] Figure 14 This is a schematic diagram of the structure of a connecting member according to another embodiment of this application; Figure 15 This is a top view schematic diagram of a connecting member according to another embodiment of this application; Figure 16 for Figure 15 The diagram shows a cross-sectional view of the connecting member along the B-B' direction.

[0179] If the reduction in thickness of the electrode terminal welding portion 31 of the connecting member 30 is not considered, the electrode terminal welding portion 31, the connecting portion 32, and the main body portion 33 can be made flush, that is, the connecting member 30 can be a uniform flat plate structure. In this way, when the thickness of the electrode terminal welding portion 31 of the connecting member 30 is less than that of the main body portion 33, this can be achieved by thinning the side of the electrode terminal welding portion 31 away from the electrode terminal 214 and / or thinning the side of the electrode terminal welding portion 31 facing the electrode terminal 214.

[0180] For example, such as Figures 14 to 16 As shown, the side of the electrode terminal welding portion 31 closest to the electrode terminal 214 can be thinned so that the thickness H31 of the electrode terminal welding portion 31 is less than the thickness H33 of the main body portion 33. Wherein, as Figure 16As shown, the thickness of the connecting portion 32 can gradually increase from the side near the electrode terminal welding portion 31 to the side near the main body portion 33, so that the electrode terminal welding portion 31 and the main body portion 33 can transition evenly and facilitate processing.

[0181] Optionally, the area of ​​the electrode terminal welding portion 31 in this embodiment of the application may be greater than or equal to the area of ​​the actual welding area between the electrode terminal 214 and the connecting member 30.

[0182] Figure 17 This is a structural schematic diagram of a connecting member according to another embodiment of this application. Figure 18 This is a top view of the connecting member according to another embodiment of this application. Figure 19 for Figure 18 The diagram shows a cross-sectional view of the connecting member along the C-C' direction.

[0183] like Figure 17-19 As shown, the connecting member 30 has two connecting portions 32 and two main body portions 33. The two connecting portions 32 are connected to the two opposite ends of the electrode terminal welding portion 31 in the first direction X. Each main body portion 33 is connected to one end of the connecting portion 32 away from the electrode terminal welding portion 31. The two connecting portions 32 and the electrode terminal welding portion 31 form a recess 336. The two main body portions 33 are connected to the two tabs 222 in a one-to-one correspondence.

[0184] It should be understood that, in this embodiment, the surface of the electrode terminal welding portion 31 facing the electrode terminal 214 protrudes beyond the surface of the main body portion 33 facing the electrode terminal 214, and the surface of the electrode terminal welding portion 31 away from the electrode terminal 214 may also protrude beyond the surface of the main body portion 33 facing the electrode terminal 214; or, unlike this, the surface of the electrode terminal welding portion 31 away from the electrode terminal 214 may also be flush with the surface of the main body portion 33 facing the electrode terminal 214. This embodiment is not limited to this. An embossed area 312 is provided on the surface of the electrode terminal welding portion 31 away from the electrode terminal 214.

[0185] Two main body parts 33 are provided, and they are connected to two tabs 222 one by one. In this way, after long-term use, if one of the main body parts 33 and the tab 222 is disconnected due to external force, the other can still remain connected, thereby improving the service life of the battery cell 20.

[0186] According to some embodiments of this application, this application also provides a battery cell 20, including an electrode terminal 214, an electrode assembly 22, and a connecting member 30 of any of the above embodiments. The electrode assembly includes a tab 222, and the connecting member 30 is used to realize the electrical connection between the electrode terminal 214 and the tab 222.

[0187] According to some embodiments of this application, this application also provides a battery 10, including a plurality of battery cells 20, wherein each battery cell 20 includes a connecting member 30 of any of the above embodiments.

[0188] According to some embodiments of this application, this application also provides an electrical device, including a battery 10, which is used to provide electrical energy to the electrical device. The battery 10 includes the connecting member 30 of any of the above embodiments.

[0189] Please see Figures 3-7 This application provides a connecting member 30 for achieving electrical connection between the electrode terminal 214 and the tab 222 of the battery cell 20. The connecting member 30 includes a main body 33 and an electrode terminal welding part 31 connected to the main body 33. The main body 33 is used to connect to the tab 222, and the electrode terminal welding part 31 is used to weld to the electrode terminal 214. The hardness of the electrode terminal welding part 31 is greater than the hardness of the main body 33. The hardness of the main body 33 is H, and the hardness of the electrode terminal welding part 31 is H1. H1 and H satisfy: 1.05≤H1 / H≤3.

[0190] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. 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 connecting member for realizing an electrical connection between an electrode terminal and a tab of a battery cell, the connecting member comprising a main body and an electrode terminal welding portion connected to the main body, the main body being used to connect to the tab, and the electrode terminal welding portion being used to weld to the electrode terminal; The hardness of the electrode terminal welding portion is greater than the hardness of the main body portion; The hardness of the main body is H, and the hardness of the electrode terminal welding part is H1. H1 and H satisfy: 1.05≤H1 / H≤3; The electrode terminal welding portion has multiple grooves on the side opposite to the electrode terminal; The electrode terminal welding portion includes a body area and an embossed area. The groove is recessed from the surface of the body area away from the electrode terminal, and the embossed area corresponds to the bottom wall of the groove. The hardness of the embossed area is greater than the hardness of the body area; The depth of the groove is 0.03mm-0.2mm.

2. The connecting member according to claim 1, characterized in that, H1 and H satisfy: 1.05≤H1 / H≤2.

3. The connecting member according to claim 1, characterized in that, The H satisfies: 20 kgf / mm 2 ≤H≤70kgf / mm 2 .

4. The connecting member according to claim 1, characterized in that, H1 satisfies: 20 kgf / mm 2 2 .​ 5. The connecting member according to claim 1, characterized in that, The thickness of the electrode terminal welding portion is less than the thickness of the main body portion.

6. The connecting member according to claim 1, characterized in that, The main body has a first surface and a second surface disposed opposite to each other along its own thickness direction, the second surface facing the electrode terminal; The connecting member includes a recess that is recessed relative to the first surface, and the electrode terminal welding portion is located at the bottom of the recess.

7. The connecting member according to claim 6, characterized in that, The connecting member further includes a connecting portion that protrudes from the second surface and connects the main body portion and the electrode terminal welding portion; The connecting portion and the electrode terminal welding portion form the recess.

8. The connecting member according to claim 7, characterized in that, The included angle between the connecting part and the main body is in the range of (91°, 130°).

9. The connecting member according to claim 7, characterized in that, The ratio of the thickness of the connecting part to the thickness of the main body is greater than or equal to 4 / 5.

10. The connecting member according to claim 5, characterized in that, The thickness H31 of the electrode terminal welding part and the thickness H33 of the main body part satisfy the following condition: 5%≤(H33-H31) / H33≤65%.

11. The connecting member according to claim 1, characterized in that, The area of ​​the surface of the electrode terminal welding part facing the electrode terminal is S1, and the area of ​​the surface of the connecting member facing the electrode terminal is S2. S1 and S2 satisfy: 1 / 50≤S1 / S2≤3 / 5.

12. A single battery cell, comprising: Electrode terminals; Electrode assembly, the electrode assembly including tabs; The connecting member as claimed in any one of claims 1 to 11, wherein the connecting member is used to realize an electrical connection between the electrode terminal and the tab.

13. A battery, comprising: A plurality of battery cells, wherein the battery cells include a connecting member as described in any one of claims 1 to 11.

14. An electrical appliance, comprising: A battery for providing electrical energy to the electrical device, the battery including a connecting member as claimed in any one of claims 1 to 11.

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