Welding method for tab area of battery cell with composite current collector and battery cell
By alternately setting metal foils in the tab area of the battery cell and riveting and welding them with metal nails to form an interlaced structure, the problems of complex and excessive thickness in traditional welding processes are solved, thus achieving simplified processes and reliable connections.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-04-10
AI Technical Summary
The welding process of the traditional composite current collector tab area is complex, which increases the number of steps and costs. The excessive thickness of the solder area affects the self-discharge performance of the cell.
Metal foils are alternately placed between the tab areas of the battery cell and riveted and welded with metal nails to form an interlaced structure, which is then metallurgically bonded by ultrasonic vibration.
The welding process has been simplified, the welding thickness in the tab area has been reduced, the connection reliability of the welding area has been improved, and the processes of roll welding and gluing have been avoided. The process is simple and easy to operate.
Smart Images
Figure CN121840132A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery technology, and in particular to a welding method for the tab region of a battery cell with a composite current collector, and a battery cell. Background Technology
[0002] The connection between the tab area and the adapter plate in traditional composite current collectors (such as PET / aluminum foil) is relatively complex. ① Increased processes and costs: Generally, a roll welding process is used, placing a layer of metal foil on both sides of the composite current collector and then connecting them together using roll welding. This extends the composite current collector and facilitates welding to structures such as adapter plates. However, roll welding leaves metal particles at the weld site, affecting the cell's self-discharge performance or causing short circuits. While a layer of adhesive is typically applied to the surface to fix the metal and prevent short circuits, this increases the number of processes and manufacturing costs.
[0003] ② Each electrode layer has two layers of metal foil in its soldering area. This results in a very thick overall soldering area; for example, a 50-layer electrode requires 100 layers of metal foil. The total thickness is the sum of the total material thickness and the interlayer wrinkle space. Furthermore, a layer of adhesive is applied to the soldering area of each electrode layer, further increasing the overall thickness of the soldering area after the electrodes are stacked. Summary of the Invention
[0004] The technical problem to be solved by the embodiments of the present invention is to provide a welding method and a battery cell with a composite current collector in the tab area, which simplifies the welding process and reduces the welding thickness of the tab area.
[0005] To address the aforementioned technical problems, this invention provides a welding method for the tab region of a battery cell with a composite current collector, comprising the following steps: Metal foils are alternately placed between the tab areas of several stacked electrode sheets in the battery cell to form a welding area; Metal nails are used to penetrate the tab area and metal foil of the welding area, and then riveted and welded.
[0006] In one feasible implementation, the battery cell includes stacked electrodes, each electrode having a tab region. The tab regions on electrodes with the same polarity are stacked along the electrode stacking direction, and there are n layers of stacked tab regions. A layer of metal foil is disposed on both sides of each tab region. A layer of metal foil is disposed between two adjacent tab regions in the stacking direction. The number of stacked layers of metal foil corresponding to the tab regions on electrodes with the same polarity is n+1.
[0007] In one feasible implementation, the n+1 layers of metal foil are stacked alternately with the n layers of tab regions in a Z-shaped stacking manner to form the welding area.
[0008] In one feasible implementation, the battery cell is a fully tabbed wound battery cell, and the metal foil, the tab region, and the electrode sheet are all the same length along the winding direction. The metal foil and the tab region are wound synchronously to form the welding area with an interlaced layered structure.
[0009] In one feasible implementation, the riveting and welding operation includes the following steps: The welding area is aligned and placed on the welding seat of the welding device. A metal nail is aligned and fixed to the welding head of the welding device, wherein the end of the metal nail furthest from the welding head is the end point, and the end point abuts against the welding area; The welding head and the welding base approach each other, driving the end to pierce the welding area and abut against the welding base, the end deforms, and the riveting is completed; The welding head and the welding seat clamp the metal nail and the welding area, and perform ultrasonic vibration on the metal nail and the welding area to metallurgically bond the metal parts that abut against each other in the welding area.
[0010] In one feasible implementation, before the welding head and the welding seat approach each other, a protective plate is placed on the side of the welding area facing the metal nail; wherein, the protective plate has a plurality of stepped holes for the metal nail to pass through, the metal nail includes a nail head and a nail body, and during riveting, the nail body passes through the stepped holes and the welding area in sequence, and the nail head is engaged with the step of the stepped hole.
[0011] In one feasible implementation, the welding base is further provided with a metal adapter, and the welding area is aligned on the metal adapter. The metal adapter is provided with a plurality of second through holes, which are aligned with the stepped holes. After the end of the metal nail pierces the welding area, it first passes through the second through holes, then abuts against the welding base, and after deformation, it is snapped onto the side of the adapter piece away from the welding area to complete the riveting.
[0012] In one feasible implementation, the metal foil has opposing first and second ends, the first end being alternately stacked with the tab region of the electrode sheet and located in the welding area, the first end being used to fix it to the tab region; the second end extending from between a plurality of tab regions, the second end being used for ultrasonic welding to a metal adapter.
[0013] In one feasible implementation, the metal nail is a hollow metal nail; the end is provided with a piercing end, and the orthographic projection area of the piercing end on the nail head gradually decreases along the axial direction of the metal nail away from the nail head; the outer wall of the nail body is provided with a curved surface structure, concave and convex textures, serrated protrusions or ribs.
[0014] Accordingly, the present invention also provides a battery cell, wherein the tab region of the battery cell is welded using the welding method for the tab region of a battery cell with a composite current collector as described in any of the preceding claims.
[0015] Implementing this invention has the following beneficial effects: The welding method for the tab region of a battery cell with a composite current collector provided in this application involves alternately placing metal foils between the stacked tab regions, effectively reducing the solder thickness in the tab region. Simultaneously, using metal foil as a molten medium solves the solder resistance problem of the polymer layer, and the reliability of the welded area connection is enhanced through metal stud riveting welding. It also avoids roll welding and adhesive application processes, resulting in a simple and easy-to-operate process that is suitable for widespread application.
[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description
[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application, and do not constitute an undue limitation of this application.
[0018] Figure 1 This is a flowchart of a welding method for the tab region of a battery cell with a composite current collector according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the positive electrode sheet of a laminated battery cell according to one embodiment of this application; Figure 3 This is a schematic diagram of the process of cross-folding metal foil in a stacked battery cell according to one embodiment of this application; Figure 4 This is an exploded view of the unfolded omnipolar loop-wound battery cell according to one embodiment of this application; Figure 5 This is a schematic diagram of the winding structure of a full-tab wound battery cell according to an embodiment of this application; Figure 6 This is a schematic diagram of the structure of the battery cell tab area before riveting and welding according to an embodiment of this application; Figure 7 This is a schematic diagram of the structure of a metal nail according to one embodiment of this application; Figure 8 This is a schematic diagram of the structure of a metal nail according to another embodiment of this application; Figure 9 This is a schematic diagram of the structure of a metal nail according to another embodiment of this application; Figure 10 This is a schematic diagram of the welding zone structure according to another embodiment of this application.
[0019] The reference numerals in the figure: 10-Positive electrode plate, 12-Active material, 13-Taper region, 20-diaphragm, 30-Negative electrode plate, 40 - Metal foil, 41 - First end, 42 - Second end 50 - Welding area; 60 - Metal nail, 61 - Nail head, 62 - Nail body, 621 - Side part 70 - Protective plate, 71 - Stepped hole 80 - Adapter piece, 81 - Second through hole X - First direction. Detailed Implementation
[0020] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0021] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.
[0022] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0023] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.
[0024] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0025] Please refer to Figure 1 One embodiment of this application provides a welding method for the tab region of a battery cell with a composite current collector, including the following steps S110-S120: S110. Metal foils are alternately arranged between several layers of electrode tabs in the battery cell to form a welding area.
[0026] The term "multiple-layered electrode tab regions" does not necessarily refer to a multi-layered structure formed by stacking multiple electrode tab regions. It can refer to multiple electrode tab regions stacked together to form a multi-layered structure, or a single electrode tab and tab region simultaneously wound to form a multi-layered structure with a single cross-sectional angle. In other words, "layered" describes a multi-layered structure, not the act of stacking itself.
[0027] The alternating arrangement refers to the alternating appearance of the tab area and the metal foil in the layered structure of the welding zone. That is, the structure is metal foil-tab area-metal foil-tab area-metal foil...tab area-metal foil, and so on. In this way, by using an alternating layering method, only one layer of metal foil is placed between adjacent tab areas, which can save costs and effectively reduce the overall thickness of the welding zone.
[0028] The electrode mainly consists of a composite current collector and an active material layer coated on the composite current collector. The portion of the composite current collector extending beyond the active material layer forms the tab region, used to connect adapter plates and other connection structures. The current collector includes a polymer layer and metal layers disposed on both sides of the polymer.
[0029] The metal foil is a highly conductive material. This application does not limit the material of the metal foil, but the materials of the metal layer and the metal foil of the electrode are matched according to the polarity of the electrode. Furthermore, the positive electrode uses aluminum foil or aluminum alloy foil, and the negative electrode uses copper foil, copper alloy foil, or nickel foil.
[0030] In one feasible implementation, please refer to Figures 2 to 3The battery cell is a laminated battery cell. The cell comprises several stacked electrode sheets, including positive and negative electrode sheets, which are stacked alternately. The tab regions on the electrode sheets of the same polarity are stacked along the stacking direction, with n layers of tab regions stacked together. A metal foil is disposed on both sides of each tab region, and a metal foil is disposed between two adjacent tab regions in the stacking direction. The number of stacked metal foil layers 40 corresponding to the tab regions on the electrode sheets of the same polarity is n+1. Specifically, the battery cell includes n positive electrode sheets 10 and n negative electrode sheets 30, which are stacked alternately, and a separator is disposed between the positive and negative electrode sheets.
[0031] In one feasible implementation, refer to Figure 2 The electrode includes a composite current collector and active material 12 coated on both sides of the composite current collector. The composite current collector has a blank area at the coating edge; this blank area is the tab region 13. This blank area, or tab region 13, is... Figure 2 The width in the first direction X is 4mm~10mm.
[0032] Based on the previous implementation methods, such as Figure 3 As shown, continuous metal foil 40 is stacked alternately with n layers of tab regions 13 in a Z-shaped stacking manner. The folded metal foil 40 forms n+1 layers, and the folded metal foil 40 and tab regions 13 together form the welding area 50. Figure 3 The letter A in the diagram is used to show the state of the metal foil 40 during folding. Figure 3 The letter B in the diagram illustrates the state of the metal foil 40 after folding. The area where the metal foil 40 overlaps with the tab region 13 is the welding area 50, which is subsequently welded. In this way, the n+1 layers of metal foil 40 are folded into a single metal foil 40, improving the overall consistency of the stacked structure and the reliability of subsequent welding.
[0033] In other feasible implementations, the n+1 layer of metal foil 40 can also be n+1 pieces of metal foil 40, which are inserted between adjacent tab regions 13 by insertion or stacking to form an interleaved stacked structure.
[0034] In one feasible implementation, please refer to Figures 4 to 5The battery cell is a fully tab-wound cell. The following description uses a composite current collector for the positive electrode and a metal foil on the tab area of the positive electrode 10 as an example. Specifically, the metal foil 40, the tab area, and the positive electrode 10 are all of the same length. The metal foil 40 and the tab area are wound synchronously to form a welding area 50 with an interlaced stacked structure. The winding operation involves pressing the metal foil 40 onto the tab area of the positive electrode 10 and stacking it with the separator 20 and the negative electrode, so that the tab area of the composite current collector and the metal foil 40 are wound together with the electrode. The overlapping portion of the metal foil 40 and the tab area of the positive electrode forms the welding area 50. The welding area 50, extending outward from the center of the cell, consists of interlaced tab areas and metal foil 40. The welding area 50 is then welded later. It should be noted that... Figures 4 to 5 Only the structure of the positive electrode tab region is shown in the diagram; the metal foil of the negative electrode tab region is not shown. In a complete fully tab-wound battery cell, a metal foil 40 of the same length (with different electrical properties) is set in the tab region of the positive electrode and the tab region of the negative electrode, and they are wound synchronously to form a layered and interlaced structure at the positive and negative electrodes, which will not be described in detail here.
[0035] In one feasible implementation, the thickness of the metal foil ranges from 5 μm to 15 μm, and the thickness of the metal foil is the length of the metal foil in the stacking direction.
[0036] S120. Use metal nails to penetrate the tab area and metal foil of the welding area, and then rivet and weld.
[0037] Among them, the metal nails not only rivet the tab area and the metal foil together, but also weld them together by ultrasonic welding, which effectively improves the reliability of the connection between the tab area and the metal foil in the welding area and improves the welding effect.
[0038] In one feasible implementation, such as Figure 3 As shown, the metal foil 40 has a first end 41 and a second end 42 opposite to each other. The first end 41 is staggered with the tab region 13 of the electrode sheet and located in the welding area 50. The first end is used to fix it to the tab region. The second end extends from between several tab regions and is used for ultrasonic welding to a metal adapter. The metal adapter can be an adapter plate / terminal in a prismatic battery or a pre-fabricated tab structure with tab adhesive in a pouch battery.
[0039] The riveting and welding operation includes the following steps S121-S124: S121. Position the welding area on the welding stand of the welding device.
[0040] The alignment of the welding area is understood as aligning the welding area with the position of the metal nail to be fixed on the welding head, so as to ensure that the metal nail on the welding head can penetrate the welding area.
[0041] S122. Align and fix the metal nail to the welding head of the welding device. The end of the metal nail furthest from the welding head is the end point, which abuts against the welding area.
[0042] Based on the previous implementation method, step S121, which involves aligning and fixing the metal nail to the welding head of the welding device, includes steps S121-S1223: S1211. Position the welding area onto the welding stand of the welding device; S1212. Obtain the protective sheet and place it on the side of the welding area away from the welding seat.
[0043] The protective plate has several stepped holes through which metal nails pass. The metal nail consists of a nail head and a nail body. During riveting, the nail body passes through the stepped holes and the welding area in sequence, and the nail head is engaged with the step of the stepped hole.
[0044] Based on the previous real-time method, before riveting, the thickness of the rivet head is 0.1mm to 0.2mm greater than the step depth of the stepped hole, so that when the rivet head is just pressed into the step of the stepped hole, the end face of the rivet head protrudes 0.1mm to 0.2mm from the surface of the protective sheet. Further, the height by which the end face of the rivet head protrudes from the surface of the protective sheet can be, but is not limited to, 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, or 0.2mm, or values between these values. After riveting, the end face of the top cap is flush with the surface of the protective sheet, and the top cap and the stepped hole are riveted with an interference fit to ensure the connection strength between the metal rivet and the protective sheet.
[0045] S123. The welding head and the welding seat approach each other, and the driving end pierces the welding area and abuts the welding seat. The end deforms to complete the riveting.
[0046] The welding seat has a riveting groove at the corresponding position. After the end of the metal nail pierces the welding area, it deforms and bends under the action of the riveting groove and the welding head. The bent part of the end of the metal nail is snapped and fixed on the side of the welding area facing the welding seat, thus completing the riveting with the welding area (similar to a staple).
[0047] In one feasible implementation, the metal nail is a hollow metal nail. Hollow metal nails are easier to pierce, and they are also more easily deformed during riveting, resulting in higher riveting stability.
[0048] In one feasible implementation, the end is provided with a piercing tip. The projected area of the piercing tip on the nail head gradually decreases along the axial direction of the metal nail away from the nail head.
[0049] In one feasible implementation, the outer wall of the nail body has a curved structure, raised or recessed texture, serrated protrusions, or ribs. When the metal nail is subjected to ultrasonic vibration, i.e., ultrasonic welding, the tab area and the metal foil are welded together, and the sides of the tab area, the metal foil, and the metal nail in contact are also welded together, resulting in a larger contact area and lower resistance. The curved structure of the metal nail's outer wall can further increase the contact area and reduce resistance.
[0050] like Figure 7 As shown, the head 61 of the metal nail 60 has a circular cross-section, and the nail body 62 includes two side bodies 621 symmetrically arranged along a plane containing the axial direction of the metal nail 60 and the radial direction of the head 61. The two side bodies 621 can be integrally formed. The projected area of the two side bodies 621 on the head 61 gradually decreases along the axial direction of the metal nail 60 towards the direction away from the head 61. Furthermore, the cross-section of the two side bodies 621 is arc-shaped. The cross-section at the connection between the side body 621 and the head 61 is semi-circular, and there is a V-shaped notch between the two side bodies 621, with the opening of the V-shaped notch at the end of the side body 621. The outer wall of the side body 621 is provided with several evenly distributed ribs, the cross-section of which is arc-shaped. This increases the contact area between the metal nail 60 and the welding area 50, thereby improving the welding effect during ultrasonic welding and reducing resistance.
[0051] like Figure 8 As shown, the head 61 of the metal nail 60 has a rectangular cross-section, and the nail body 62 includes two side bodies 621 symmetrically arranged along the plane containing the axis of symmetry of the head 61 and the axis through which the metal nail 60 is oriented. The two side bodies 621 can be integrally formed. The orthographic projection area of the ends of the two side bodies 621 on the head 61 gradually decreases along the axis of the metal nail 60 in the direction away from the head 61. The cross-section of the two side bodies 621 is rectangular. The longitudinal section of the side bodies 621 is trapezoidal, and the ends of the side bodies 621 are wedge-shaped. The outer wall surface of the side bodies 621 has corrugated protrusions to increase the contact area between the metal nail 60 and the tab area 13 and the metal foil 40 of the welding area 50. The distance between the inner walls of the two side bodies 621 remains constant, while the distance between the outer walls of the two side bodies 621 gradually shortens until it approaches the distance between the inner walls. The corrugated protrusions are provided in the area where the distance between the outer walls is not reduced.
[0052] like Figure 9As shown, the cross-section of the nail head 61 of the metal nail 60 is rectangular, and the nail body 62 includes two side bodies 621 symmetrically arranged along the plane containing the axis of symmetry of the nail head 61 and the axial direction of the metal nail 60. The two side bodies 621 can be integrally formed. The orthographic projection area of the ends of the two side bodies 621 on the nail head 61 gradually decreases along the axial direction of the metal nail 60 in the direction away from the nail head 61. The cross-section of the two side bodies 621 is rectangular. The longitudinal section of the side body 621 is trapezoidal, and the ends of the side bodies 621 are wedge-shaped. The outer wall surface of the side body 621 has serrated protrusions, and the degree of serrations gradually decreases along the axial direction of the metal nail 60 in the direction away from the nail head 61, so as to increase the contact area between the metal nail 60 and the tab area 13 and the metal foil 40 of the welding area 50, and at the same time increase the cross-sectional area of the piercing end to reduce the contact area during piercing and increase the pressure.
[0053] S124. The welding head and welding seat clamp the metal nail and the welding area, and perform ultrasonic vibration on the metal nail and the welding area to metallurgically bond the metal parts that abut against each other in the welding area.
[0054] In this process, the metal parts that abut each other in the welding area are metallurgically bonded. Ultrasonic vibration can metallurgically bond the metal layers that abut each other within the vibration range, which is welding, thereby achieving welding fixation. Step S124 uses ultrasonic vibration on the metal nail to metallurgically bond the metal layer and metal foil in the tab area of the welding area. At the same time, the metal layer and metal foil in the tab area are welded to the sidewall of the welding nail, resulting in a larger contact area and lower resistance.
[0055] Based on the previous implementation method, after ultrasonic welding, the end face of the nail head is flush with the surface of the protective sheet.
[0056] After the riveting and welding (steps S121-S124) are completed, step S125 is also included: The second end of the metal foil is ultrasonically welded to the metal adapter.
[0057] In one feasible implementation, please refer to Figure 6 and Figure 10 As shown, the projection of each metal foil 40 in the stacking direction falls completely on the tab area 13. That is, all metal foils 40 overlap with the tab area 13 and are all within the welding area 50. The term "equal area" here means that the areas are approximately the same; slight differences are permissible to facilitate layering, etc. The riveting welding operation includes the following steps: S221. A metal adapter is provided on the welding base; S222. The welding area is aligned and placed on the metal adapter, with the metal adapter at least partially overlapping the welding area. S223. Obtain the protective sheet and place it on the side of the welding area away from the metal adapter. S224. Fix the metal nail to the welding head. Based on the previous implementation methods, such as Figure 6 As shown, the protective plate 70 has several stepped holes 71. A metal nail 60 is inserted into each stepped hole 71. The metal nail 60 includes a nail head 61 and a nail body 62. The connection between the nail head 61 and the nail body 62 has a stepped structure. The stepped hole 71 has a step that mates with the stepped structure, and the nail head 61 can be snapped onto the step.
[0058] S225, the welding head and the welding seat approach each other, the end of the driving metal nail passes through the stepped hole, pierces the welding area 50 and abuts the welding seat through the metal adapter, the end deforms, and the riveting is completed.
[0059] S226. Apply ultrasonic vibration to the metal nail to metallurgically bond the metal layers of the welding area to the contact metal layers of the component.
[0060] The protective plate is similar in structure to the aforementioned protective plate, and will not be described again here. The metal adapter 80 is provided with several second through holes 81, which are aligned with the stepped holes 71. The end of the metal nail 60 first passes through the stepped hole, then pierces the welding area 50, and then passes through the second through hole 81, finally abutting the welding seat, and the deformation completes the riveting.
[0061] In one feasible implementation, the metal foil is a highly conductive material. It can be understood that this application does not limit the material of the metal foil, but the materials of the metal layer, metal foil, adapter sheet, and protective sheet of the electrode are matched according to the polarity of the electrode. Furthermore, the positive electrode is made of aluminum, and the negative electrode is made of copper.
[0062] The welding method for the tab region of a battery cell with a composite current collector provided in this application involves alternately placing metal foils between the stacked tab regions, effectively reducing the solder thickness in the tab region. Simultaneously, using metal foil as a molten medium solves the solder resistance problem of the polymer layer, and the reliability of the welded area connection is enhanced through metal stud riveting welding. It also avoids roll welding and adhesive application processes, resulting in a simple and easy-to-operate process that is suitable for widespread application.
[0063] This application also provides a battery cell, wherein the tab region of the battery cell is welded using any of the above-described welding methods for battery cell tab regions with composite current collectors.
[0064] The battery cell provided in this application embodiment has a small solder thickness in the tab area, uses metal foil as a melting medium in the tab area to solve the problem of solder resistance in the polymer layer, and enhances the reliability of the connection in the welding area by riveting with metal nails.
[0065] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0066] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.
Claims
1. A welding method for the tab region of a battery cell with a composite current collector, characterized in that, Includes the following steps: Metal foils are alternately placed between the tab areas of several stacked electrode sheets in the battery cell to form a welding area; Metal nails are used to penetrate the tab area and metal foil of the welding area, and then riveted and welded.
2. The welding method for the electrode tab region of the battery cell with composite current collector according to claim 1, characterized in that, The battery cell includes stacked electrodes, each electrode having a tab region. The tab regions on electrodes with the same polarity are stacked along the electrode stacking direction, and there are n layers of stacked tab regions. A layer of metal foil is disposed on both sides of each tab region. A layer of metal foil is disposed between two adjacent tab regions in the stacking direction. The number of stacked metal foil layers corresponding to the tab regions on electrodes with the same polarity is n+1.
3. The welding method for the electrode tab region of the battery cell with composite current collector according to claim 2, characterized in that, The metal foil of layer n+1 is stacked alternately with the tab area of layer n in a Z-shaped stacking manner to form the welding area.
4. The welding method for the electrode tab region of the battery cell with composite current collector according to claim 1, characterized in that, The battery cell is a full-tab wound battery cell. The metal foil, the tab area, and the electrode sheet are all the same length along the winding direction. The metal foil and the tab area are wound synchronously to form the welding area with an interlaced layered structure.
5. The welding method for the electrode tab region of the battery cell with composite current collector according to claim 1, characterized in that, The riveting and welding operation includes the following steps: The welding area is aligned and placed on the welding seat of the welding device. A metal nail is aligned and fixed to the welding head of the welding device, wherein the end of the metal nail furthest from the welding head is the end point, and the end point abuts against the welding area; The welding head and the welding base approach each other, driving the end to pierce the welding area and abut against the welding base, the end deforms, and the riveting is completed; The welding head and the welding seat clamp the metal nail and the welding area, and perform ultrasonic vibration on the metal nail and the welding area to metallurgically bond the metal parts that abut against each other in the welding area.
6. The welding method for the electrode tab region of the battery cell with composite current collector according to claim 5, characterized in that, Before the welding head and the welding base come close to each other, a protective sheet is placed on the side of the welding area facing the metal nail; The protective plate has several stepped holes for the metal nails to pass through. The metal nails include a nail head and a nail body. During riveting, the nail body passes through the stepped holes and the welding area in sequence, and the nail head is engaged with the step of the stepped hole.
7. The welding method for the electrode tab region of the battery cell with composite current collector according to claim 6, characterized in that, The welding base is also equipped with a metal adapter. The welding area is aligned and placed on the metal adapter. The metal adapter is provided with a plurality of second through holes, which are aligned with the stepped holes. After the end of the metal nail pierces the welding area, it first passes through the second through hole, then abuts against the welding seat, and after deformation, it is snapped onto the side of the adapter piece away from the welding area to complete the riveting.
8. The welding method for the electrode tab region of the battery cell with composite current collector according to claim 6, characterized in that, The metal foil has a first end and a second end opposite to each other. The first end is stacked alternately with the tab area of the electrode sheet and is located in the welding area. The first end is used to fix the tab area. The second end extends from between a plurality of tab areas and is used for ultrasonic welding with a metal adapter.
9. The welding method for the electrode tab region of the battery cell with composite current collector according to claim 6, characterized in that, The metal nail is a hollow metal nail; The end is provided with a piercing end, and the projected area of the piercing end on the nail head gradually decreases along the axial direction of the metal nail in the direction away from the nail head; The outer wall of the nail body is provided with a curved structure, concave and convex textures, serrated protrusions or ribs.
10. A battery cell, characterized in that, The tab region of the battery cell is welded using the welding method for the tab region of the battery cell with composite current collector as described in any one of claims 1 to 9.