Rivets for anode covers of battery cells and anode covers of battery cells

Abstract

The utility model relates to a rivet (10) for the anode cover (1) of battery cell, rivet (10) includes the pole structure (3) and board (2), the board has the blind hole (21) for receiving the pole structure (3) partially, wherein, the pole structure (3) and board (2) are connected with each other through welding, wherein, the connection of pole structure (3) and board (2) is the shape fit connection in the blind hole (21) of board (2). In addition, the utility model relates to an anode cover comprising rivet (10).

Description

Technical Field

[0001] This utility model relates to a rivet for an anode cap of a battery cell, preferably a prismatic battery cell. Furthermore, this utility model relates to an anode cap for a battery cell, the anode cap including the rivet. Background Technology

[0002] A battery is a power source and comprises one or more battery cells. A battery may contain a single cell (such as an AA battery) or multiple cells (such as those used in laptops or electric vehicles).

[0003] A battery cell is a device that generates electrical energy. A battery cell may include an anode (negative electrode), a cathode (positive electrode), an electrolyte, and a battery cell casing. The electrolyte facilitates the movement of ions between the electrodes.

[0004] The battery cell housing may include a cell canister (e.g., a prismatic cell canister) and two cell covers that seal the cell canister to prevent electrolyte leakage. One cell cover represents the cathode cover (positive electrode cover) located at the positive electrode, and the other cell cover represents the anode cover (negative electrode cover) located at the negative electrode.

[0005] Typically, an anode cap includes terminals, an upper insulating portion, a base plate, a sealing ring, a lower insulating portion, and rivets. Terminals are conductive components that provide electrical connections between the battery cell and an external circuit or device. They facilitate the transfer of current from the battery to the device it powers. Rivets are mechanical components used to connect the electrodes to the terminals to securely fasten the battery cap components and maintain a tight seal to prevent electrolyte leakage.

[0006] Due to copper's high electrical conductivity and chemical stability in the anodic environment, rivets and current collectors for the anode are often made of copper. However, the terminals of the battery cell cover are primarily made of aluminum to ensure similar weld strength when connected to the busbar, which serves as the electrical interconnect between the battery cell, module, and external circuitry, ensuring efficient current distribution, thermal management, and mechanical stability. Therefore, at the current level of technology, rivets made of copper (copper rivets) are welded to terminals made of aluminum (aluminum terminals), forming an intermetallic weld joint.

[0007] In battery cell development, the lifespan and reliability of the mechanical components are crucial. Cracks often form in the welds between the copper rivets and aluminum terminals used in current cover designs. These cracks can lead to loosening of the connection between the terminals and rivets, resulting in electrolyte leakage or other damage to the cell. Furthermore, cracks can cause higher contact resistance. Cracking between aluminum and copper can be caused by thermal stress, which results from incompatible material properties, the formation of brittle intermetallic compounds, and insufficient welding parameters.

[0008] Several techniques exist for joining parts made of different metals, such as parts made of copper and parts made of aluminum. For example, the connection can be formed by laser welding or barrel plating. Alternatively, the materials of the terminals or rivets can be chosen such that both the terminals and rivets are made of the same material, and a single-metal connection can be formed.

[0009] US 2018 178312 A1 and JP 2009 285678 A describe further examples of metal parts used to connect batteries.

[0010] However, connections known with current technology are either not robust enough or cannot be formed using this technology. Therefore, the purpose of this invention is to provide a stable and electrically conductive rivet.

[0011] This objective is achieved by the rivet and anode cap for the anode cap of the battery cell disclosed in this invention. Utility Model Content

[0012] According to a first aspect, the present invention relates to a rivet for an anode cap of a prismatic battery cell, the rivet comprising a rod structure and a plate having a blind hole for partially receiving the rod structure, wherein the rod structure and the plate are connected to each other by welding, wherein the connection between the rod structure and the plate is a form-fit connection within the blind hole of the plate.

[0013] According to a second aspect, the present invention relates to an anode cap comprising rivets according to the first aspect.

[0014] Further aspects of the present invention are set forth in the dependent claims, the following description, and the accompanying drawings.

[0015] A rivet for an anode cap of a battery cell, preferably a prismatic battery cell, includes a rod structure and a plate having a blind hole for partially receiving the rod structure. The rod structure and the plate are joined to each other by welding, wherein the connection between the rod structure and the plate is a form-fit connection within the blind hole of the plate. Because the welded connection extends throughout the blind hole, a larger surface area is available for the welded connection compared to welding the rod structure to the surface of a plate without a blind hole. Therefore, the stability of the connection is improved efficiently.

[0016] Blind holes can be in the form of cylinders, truncated cones or inverted truncated cones, double-layered discs or similar forms.

[0017] In some embodiments, the first diameter of the blind hole at the surface of the plate may be smaller than the second diameter of the blind hole at the bottom of the blind hole, or the third diameter of the blind hole at a location between the surface and the bottom of the blind hole. In other words, the blind hole of the plate has a barbed hook structure. During welding, the end portion of the rod structure is plasticized and filled with the barbed hook structure to form a shape-fit connection. Therefore, the tensile strength of the connection between the rod structure and the plate is increased.

[0018] In some embodiments, blind holes are formed such that the transition from the surface of the plate to the bottom of the blind hole is straight, curved, or stepped. For example, a blind hole may be formed as part of a cone shape (i.e., a truncated cone), thus achieving a straight transition from the surface of the plate to the bottom of the blind hole. Alternatively, a blind hole may be formed as a stack of at least two discs (double discs), thus achieving a stepped transition from the surface of the plate to the bottom of the plate. This form may be referred to as a cavity structure. Blind holes may have other shapes that have similar effects to the proposed shapes.

[0019] In some embodiments, the rod structure may have a main portion and an end portion that is inserted into a blind hole in the plate, wherein the end portion is cylindrical or conical before welding. Alternatively, the main portion of the rod structure may be cylindrical.

[0020] In some embodiments, the diameter of the end portion of the rod structure may be equal to or smaller than the diameter of the main portion of the rod structure. Preferably, the diameter of the end portion of the rod structure is selected such that the end portion fits perfectly into the blind hole of the plate. Preferably, the diameter of the end portion is substantially equal to the first diameter of the blind hole at the surface of the plate.

[0021] When the diameter of the end portion is smaller than that of the main portion, the surface area for welding is further increased because the front end of the main portion of the rod structure, oriented towards the end portion of the rod structure, connects to the surface portion of the plate surrounding the blind hole. Therefore, the robustness of the connection can be further improved.

[0022] In some embodiments, the length of the end portion of the rod structure may be slightly greater than the depth of the blind hole in the plate before welding. The length of the end portion is preferably the distance between the front end of the end portion of the rod structure oriented away from the main portion and the front end of the main portion, preferably the main portion, oriented towards the end portion. The depth of the blind hole is preferably the distance between the surface of the plate and the bottom of the blind hole. As the end portion of the rod structure plasticizes during welding, it deforms and fills (preferably completely fills) the blind hole to form a form-fit connection between the rod structure and the plate. During this process, the length of the end portion is reduced to a length equal to the depth of the blind hole in the plate.

[0023] In some embodiments, the rod structure and the plate can be connected to each other by friction welding or semi-molten rolling processes.

[0024] In some embodiments, the plate may be made of copper or a copper alloy. Copper provides high electrical conductivity and chemical stability in an anodic environment. The plate may be manufactured by grinding, stamping, CNC machining, or other suitable methods.

[0025] In some embodiments, the rod structure may be made of aluminum or an aluminum alloy. Using a rod structure made of aluminum is advantageous because it simplifies the connection to the aluminum terminals.

[0026] In some embodiments, the bottom of the blind hole and / or the front end of the end portion of the rod structure of the plate may have a rough surface before welding. For example, the bottom of the blind hole and / or the front end of the end portion of the rod structure of the plate may be provided with a rough serrated structure before welding. Therefore, the welding process can be accelerated.

[0027] The following text describes an example of the friction welding process.

[0028] During the preparation phase, the plates and rod structures to be welded can be prepared with clean and properly machined surfaces. Subsequently, the end portions of the rod structures can be inserted into blind holes in the plates.

[0029] During the friction phase, the rotatable rod structure remains stationary while the plate is held stationary, and a controlled axial force can be used to press the rod structure and plate together. The friction between the end portions of the rod structure and the plate generates heat, softening the interface without melting the material.

[0030] During the burn-off stage, the material at the interface between the rod structure and the plate begins to plasticize and is extruded outward, forming a flash. The plasticized and extruded material can be pushed into the gap between the end portion of the rod structure and the blind hole in the plate. This can create barbed hooks, resulting in higher tensile strength at the joint. Impurities and oxides are discharged from the joint.

[0031] During the forging stage (upsetting stage), rotation can be stopped, and additional axial force can be applied to solidify the weld. The softened materials fuse together, forming a strong metallurgical bond.

[0032] During the cooling phase, the welded joint can be cooled under pressure to prevent defects.

[0033] In some embodiments, the rivet may be a terminal that can be attached to the anode cap of the battery cell. Preferably, the rivet and the terminal are connected by welding (e.g., by laser welding).

[0034] This utility model further relates to an anode cover. As described above in the background section of this utility model, the anode cover may include terminals, an upper insulating portion, a base plate, a lower insulating portion, rivets as described above according to this utility model, and a sealing ring.

[0035] Terminals can be conductive components that provide electrical connection points for the battery cell to an external circuit or device. They facilitate the transfer of current from the battery to the device it powers. A battery cell may have two terminals: a positive terminal (cathode) where current flows out and a negative terminal (anode) where current flows in. The positive and negative terminals ensure a safe and efficient connection to the powered device. Terminals may comprise conductive materials selected from the group consisting of copper, aluminum, or composites thereof. Preferably, the terminals are made of aluminum to simplify soldering of terminals and busbars.

[0036] The upper and lower insulating portions can be components that provide electrical insulation and mechanical protection. The upper insulating portion of the anode cover can be a component located between the negative terminal and the base plate of the anode cover. The upper insulating portion can prevent electrical short circuits by insulating the terminals of the anode cover from the cell housing, and / or provide a barrier to protect internal components from mechanical stress or damage. The lower insulating portion can be a component located between the base plate of the anode cover and the rivets of the anode cover. The lower insulating portion can prevent electrical short circuits by insulating the terminals of the anode cover from the cell housing, and / or provide a barrier to protect internal components from mechanical stress or damage. The upper and / or lower insulating portions can be made of plastics selected from the group consisting of polypropylene, polyethylene, polycarbonate, polyamide, and / or polyvinyl chloride.

[0037] The base plate can be a component that is attached to the cell can to cover the open end of the cell can and prevent electrolyte leakage.

[0038] The sealing ring can be an annular component of the anode cap positioned between the base plate and the rivet. Preferably, the sealing ring is designed to fit precisely between the base plate and the lower plastic insulation portion to prevent electrolyte leakage. The sealing ring can be made of an elastomeric material, such as nitrile rubber, silicone rubber, fluorinated elastomers, ethylene propylene diene monomer, and / or neoprene rubber.

[0039] Rivets have a rod structure and a plate, and are formed as described above. Rivets can be used to connect active cell components (such as electrodes) to terminals to securely connect components of the battery cover and maintain a tight seal to prevent electrolyte leakage.

[0040] Each of the lower insulating portion, sealing ring, base plate, upper insulating portion, and terminal may have a hole. The rivet, lower insulating portion, sealing ring, base plate, upper insulating portion, and terminal are preferably stacked on top of each other, such that the rod structure, preferably the main part of the rod structure, passes through the holes in the lower insulating portion, sealing ring, base plate, upper insulating portion, and terminal. The rivet, particularly the main part of the rod structure, is connected to the terminal, preferably welded to the terminal, to secure the components of the stack.

[0041] The rivet of this invention allows for the use of different materials for the rod structure and plate, making it easy to integrate into the anode cap. At the same time, the rivet is robust, thus improving the quality and lifespan of the anode cap and the entire battery cell. Attached Figure Description

[0042] The embodiments of this utility model are explained by way of example with reference to the accompanying drawings, in which: Figure 1 An exploded view of the anode cap of the battery cell is shown; Figure 2a A first embodiment of riveting is shown before assembling the rod structure and plate and before friction welding; Figure 2b A first embodiment of riveting is shown after the rod structure is partially inserted into a blind hole in the plate and before welding; Figure 2c A first embodiment of a rivet following friction welding is shown; Figure 3a A second embodiment of riveting is shown, performed before assembling the rod structure and plate and before friction welding; Figure 3b A second embodiment is shown, in which the rivet is riveted after the rod structure is partially inserted into the blind hole of the plate and before welding; Figure 3c A second embodiment of the rivet following friction welding is shown; Figure 4 A third embodiment of the rivets is shown, prior to the assembly of the rod structure and plate, and prior to friction welding; and Figure 5 A fourth embodiment of riveting is shown, performed before assembling the rod structure and plate and before friction welding. Detailed Implementation

[0043] Figure 1 An exploded view of the anode cover 1 of the battery cell is shown, which includes rivets 10 for securing the various components of the anode cover 1 to each other when they are connected to terminals 11. The rivets 10 have plates 2 and a rod structure 3 connected to the middle of the plates 2.

[0044] The anode cover 1 includes, from bottom to top, a rivet 10, a lower insulating layer 12, a sealing ring 13, a base plate 14, an upper insulating layer 15, and a terminal 11. In the completed state of the battery cell, the plates 2 of the lower insulating layer 12 and the rivet 10 are oriented towards the cell canister of the battery cell and in contact with the electrolyte within the cell canister. The terminal 11 is oriented away from the cell canister.

[0045] The lower insulating layer 12 has the dimensions of the front opening of the battery cell can and includes a hole for inserting the rod structure 3 of the rivet 10. The extension of the plate 2 of the rivet 10 is smaller than the extension of the lower insulating layer 12. The sealing ring 5 is a conventional sealing ring with a hole for inserting the rod structure 3. The base plate 14 is a plate for covering the front opening of the battery cell can (not shown) and has a hole for inserting the rod structure 3. The upper insulating layer 15 has substantially the same dimensions as the plate 2 of the rivet 10 and also has a hole for inserting the rod structure 10. The terminal 11 has substantially the same dimensions as the upper insulating layer 15 and also has a hole for inserting the rod structure 3.

[0046] The rod structure 3 of the terminal 11 and the rivet 10 can be connected to each other by welding and is configured to fix the lower insulating layer, sealing ring 13, base plate 14 and upper insulating layer 15 to each other. Several embodiments of the rivet 10 are described below.

[0047] Figures 2a to 2c A first embodiment of the rivet 130 according to the present invention is shown. Figure 2a The plate and rod structure are shown separately before they are assembled into the rivet 10. Plate 2 has a surface 20. A blind hole 21 is formed in the middle of surface 20. The blind hole 21 has the form of a truncated cone. In other words, the blind hole 21 has a first diameter d1 at surface 20 of plate 2 and a second diameter d2 at its bottom 22, which is positioned at a depth d from surface 20 of plate 2. The first diameter d1 is smaller than the second diameter d2, thus creating a ring-like undercut 23 and therefore a barbed hook structure.

[0048] The rod structure 3 has an end portion 30 and a main portion 31. Both the end portion 30 and the main portion 31 are cylindrical. The diameter d of the main portion 31 is... m The diameter d is greater than 30 of the end portion. e .

[0049] The diameter d of the end portion 30 e Approximately equal to the diameter d1 of plate 2, so that the end portion 30 fits perfectly into the blind hole 21 in plate 2, such as... Figure 2bAs shown in the figure, the rivet 10 is inserted after the end portion 30 of the rod structure 3 is inserted into the blind hole 21 of the plate 2, but before friction welding. When the end portion 30 is inserted into the blind hole 21, a gap 40 is created between the end portion 30 and the blind hole 21, particularly in the region of the ring-shaped undercut 23.

[0050] The length l of the end portion 30 of the rod structure 3 is slightly longer than the depth d of the blind hole 21. Therefore, as by Figure 2b As shown, there is a groove 41 between the surface 20 of the plate 2 and the front end portion 32 of the main portion 31, with the front end portion 32 oriented toward the end portion 30.

[0051] During friction welding, the material of the end portion 30 of the rod structure made of aluminum is plasticized and deformed. As the rod structure 3 is pressed towards the plate 2, the plasticized material of the end portion 30 is pressed into the gap 40 between the end portion 30 and the blind hole 21, and the groove 41 between the front end 32 of the main portion 31 and the surface 20 of the plate 2 disappears, as... Figure 2c As shown in the figure, this figure represents rivet 2 after friction welding. Because the material of the end portion 30 extends into the gap 40 to form a form-fit connection, the strength of the welded connection is increased, resulting in high stability and robustness of rivet 10.

[0052] Figures 3a to 3c A second embodiment of the rivet 10 according to the present invention is shown. Figure 3a The rivet 10 is shown before assembling the rod structure 3 and plate 2. (See also: Regarding...) Figure 2a The rod structure 2 is formed as explained. Plate 2 has a surface 20 and a blind hole 21 in the middle of surface 20, wherein the blind hole 21 has: a first cylindrical region 24 having a first diameter d1 and adjacent to surface 20; and a second cylindrical region 25 having a second diameter d2 and adjacent to the bottom 22 of blind hole 21. The first diameter d1 is smaller than the second diameter d2, and the first diameter d1 is approximately equal to the diameter d of the end portion 30 of rod structure 3. e .

[0053] Figure 3b This refers to the rivet 10 after the end portion 30 of the rod structure 3 is inserted into the blind hole 21 of the plate 2, but before friction welding. (As per...) Figure 3b As shown, the end portion 30 is fitted into the blind hole 21, and a ring-like gap 40 appears between the end portion 30 and the blind hole 21. Furthermore, a groove 41 exists between the front end portion 32 of the main portion 31 and the surface 20 of the plate 2.

[0054] After friction welding, the end portion 30 deforms, causing the gap 40 to be filled with the material of the end portion 30, and the groove 41 between the front end 32 of the rod structure 3 and the surface 20 of the plate 2 disappears, thus forming a form-fit connection. This is due to Figure 3c As shown. Therefore, a rivet 10 with a strong connection is provided.

[0055] Figure 4 A third embodiment of the rivet 10 according to the present invention is shown before assembling the rod structure 3 and the plate 2. The rod structure 3 has a cylindrical end portion 30 and a cylindrical main portion 31. The plate 2 has a surface 20 and a blind hole 21. The blind hole 21 has a cylindrical shape and has a diameter d approximately equal to that of the end portion 30. e The diameter d1 and the depth d, which is approximately equal to the length l of the end portion 30, allow the entire end portion 30 to fit perfectly into the blind hole 21 in the plate 2, thus creating a form-fit connection. Because the welding surface is increased through the blind hole 21, the rivet 10 is robust and stable.

[0056] Figure 5 A fourth embodiment of the rivet 10 according to the present invention is shown before assembling the rod structure 3 and the plate 2. The rod structure 3 has a conical end portion 30 and a cylindrical main portion 31. The end portion 30 has a first front end portion 33 oriented away from the main portion 31 and a second front end portion 34 oriented towards the main portion 31, wherein the diameter of the first front end portion 33 is smaller than the diameter of the second front end portion 34. The plate 2 has a surface 20 and a blind hole 21. The blind hole 21 has a conical shape, wherein the diameter d1 of the blind hole 21 at the surface 20 is larger than the diameter d2 of the blind hole 21 at the bottom 22 of the blind hole 21. The end portion 30 of the rod structure 3 has a shape approximately equal to the shape of the blind hole 21, such that the entire end portion 30 fits perfectly into the blind hole 21 in the plate 2, thus creating a form-fit connection. Because the welding surface is increased through the blind hole 21, the rivet 10 is robust and stable.

[0057] Figure Labels 1. Anode cap 10 rivets 11 terminals 12 Lower insulation layer 13 Sealing ring 14. Base Plate 15. Upper insulation layer 2 boards 20 Surface 21 Blind Holes 22 Bottom of blind hole Type 23 circumferential undercut 24 First cylindrical region 25 Second cylindrical region 3-bar structure 30 End portion 31 Main Parts 32. The front end of the main part oriented towards the end portion. 33 The first front end portion of the end portion oriented away from the main portion 34 The second front end portion oriented toward the main portion of the end portion 40 gap 41 slots The first diameter of d1 blind hole The second diameter of d2 blind hole d e Diameter of the end portion of the rod structure d m Diameter of the main part of the rod structure d depth l length

Claims

1. A rivet (10) for an anode cap (1) of a battery cell, the rivet (10) comprising a rod structure (3) and a plate (2), the plate having a blind hole (21) for partially receiving the rod structure (3), wherein, The rod structure (3) and the plate (2) are connected to each other by welding, wherein the connection between the rod structure (3) and the plate (2) is a shape fit connection within a blind hole (21) of the plate (2).

2. The rivet (10) according to claim 1, wherein, The first diameter (d1) of the blind hole (21) at the surface (20) of the plate (2) is smaller than the second diameter (d2) of the blind hole (21) at the bottom (22) of the blind hole (21).

3. The rivet (10) according to claim 2, wherein, The transition from the surface (20) of the plate (2) to the bottom (22) of the blind hole (21) is straight, curved, or stepped.

4. The rivet (10) according to any one of claims 1 to 3, wherein, The rod structure (3) has a main part (31) and an end part (30), the end part (30) being inserted into a blind hole (21) of the plate (2), wherein the end part (30) is cylindrical or conical before welding.

5. The rivet (10) according to claim 4, wherein, The diameter (d) of the end portion (30) of the rod structure (3) e The diameter (d) of the main part (31) of the rod structure (3) is less than or equal to that of the rod structure (3). m ).

6. The rivet (10) according to claim 4, wherein, The length (l) of the end portion (30) of the rod structure (3) is slightly greater than the depth (d) of the blind hole (21) of the plate (2) before welding.

7. The rivet (10) according to claim 5, wherein, The length (l) of the end portion (30) of the rod structure (3) is slightly greater than the depth (d) of the blind hole (21) of the plate (2) before welding.

8. The rivet (10) according to any one of claims 1 to 3, wherein, The rod structure and the plate are connected to each other by friction welding or semi-molten rolling processes.

9. The rivet (10) according to any one of claims 1 to 3, wherein, The plate (2) is made of copper or a copper alloy.

10. The rivet (10) according to any one of claims 1 to 3, wherein, The rod structure (3) is made of aluminum or aluminum alloy.

11. An anode cap (1) for a battery cell, the anode cap comprising a rivet (10) according to any one of claims 1 to 10.

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