Pole piece, battery and processing method of pole piece

Abstract

The present disclosure relates to the technical field of batteries, and particularly relates to a pole piece, a battery and a processing method of the pole piece. The pole piece provided by the present disclosure comprises a composite current collector and an adapter; the composite current collector comprises a first end portion located at one side of the composite current collector; the adapter is arranged at the first end portion of the composite current collector; at least part of the adapter overlaps with the first end portion; and the adapter and the first end portion are metallurgically combined through ultrasonic roll welding; and the area where the adapter is located constitutes a laser welding area for laser welding with a pole lug. The present disclosure solves the industry problem that the composite current collector cannot be directly laser welded.

Description

Technical Field

[0001] This disclosure relates to the field of battery technology, and in particular to an electrode, a battery, and a method for processing the electrode. Background Technology

[0002] With the rapid development of new energy vehicles and the energy storage industry, large cylindrical all-tab lithium-ion batteries have become an important development direction in the current power battery field due to their high energy density, good heat dissipation performance, and advantages in large-scale production. Composite current collectors, as a new type of battery current collector structure, are typically composed of an intermediate insulating polymer layer and an ultra-thin metal layer on the surface. They have advantages such as lightweight, high safety, and controllable cost, and their application demand in the battery field is increasing.

[0003] However, during the assembly of large cylindrical all-tab batteries, it is necessary to make a large-area, low-impedance electrical connection between the current collector and the battery cover or casing. Traditional laser welding methods have high requirements for the conductivity, heat fusion and thickness consistency of the materials. The intermediate insulating polymer layer of the composite current collector cannot conduct current and heat, and its ultra-thin metal conductive layer has extremely low heat capacity. Under the instantaneous impact of high-energy laser, it is easily ablated, broken down or produces uncontrollable welding spatter, resulting in connection failure, excessive resistance, or even damage to the current collector body. Summary of the Invention

[0004] This disclosure provides an electrode sheet, a battery, and a method for processing the electrode sheet, in order to at least solve the above-mentioned technical problems existing in the prior art.

[0005] The first aspect of this disclosure provides an electrode, comprising: a composite current collector and an adapter;

[0006] The composite current collector includes a first end located on one side of the composite current collector, the adapter is disposed at the first end of the composite current collector, at least a portion of the adapter overlaps with the first end, and the adapter and the first end are metallurgically bonded by ultrasonic roll welding; The area where the adapter is located constitutes a laser welding zone for laser welding with the electrode.

[0007] Furthermore, the adapter is a continuous metal strip, and the continuous metal strip is the same length as the composite current collector.

[0008] Furthermore, the adapter includes multiple sub-adapters, which are arranged at equal or non-equal intervals at the first end.

[0009] Furthermore, the composite current collector includes a first conductive layer, a second conductive layer, and an insulating layer disposed between the first conductive layer and the second conductive layer; The adapter is connected to one of the first conductive layer and the second conductive layer by ultrasonic roll welding.

[0010] Furthermore, there are two adapters, one of which is connected to the first conductive layer by ultrasonic roll welding, and the other is connected to the second conductive layer by ultrasonic roll welding.

[0011] Furthermore, the ultrasonic roll welding forms a continuous linear welded section, and the linear welded section forms one or more connecting ribs; Alternatively, the ultrasonic roll welding forms multiple discontinuous linear welded sections.

[0012] Furthermore, the adapter is an aluminum or copper strip with a thickness of 0.01 mm to 0.03 mm.

[0013] A second aspect of this disclosure provides a battery including the electrode described in the first aspect.

[0014] This disclosure provides a method for processing electrode sheets, comprising the following steps: An adapter is provided at the first end of the composite current collector, such that at least a portion of the adapter overlaps with the first end. The adapter is rolled and ultrasonically welded onto the conductive layer on the surface of the composite current collector using ultrasonic rolling welding equipment, so that the adapter and the conductive layer on the surface of the composite current collector form a metallurgical bond. Laser weld the adapter to the electrode.

[0015] Furthermore, the welding head of the ultrasonic roll welding equipment is a circular rotatable structure. The welding head rotates synchronously with the composite current collector and the adapter in the direction of their respective feed directions, so that the welding head welds the first end of the composite current collector to the adapter during the rotation process.

[0016] The technical solution provided in this disclosure has the following advantages compared with the prior art: The electrode provided in this embodiment includes a composite current collector and an adapter. The composite current collector includes a first end located on one side of the composite current collector, which is typically a tab connection area. The adapter is disposed at the first end of the composite current collector, with at least a portion of the adapter overlapping the first end, and the adapter and the first end are metallurgically bonded by ultrasonic roll welding. The metallurgical bond between the adapter and the composite current collector through ultrasonic roll welding eliminates the risk of incomplete welding and aging at the interface. The mechanical connection strength and conductivity stability are significantly superior to conductive adhesive bonding and ordinary ultrasonic spot welding, meeting the requirements for high current and high reliability connection of large cylindrical full-tab electrodes. The area where the adapter is located constitutes a laser welding area for laser welding with the tab. The laser welding area is a standard pure metal area, which can directly utilize existing mature laser welding processes and equipment for large cylindrical batteries without modifying the back-end production line. The process is simple, efficient, and has large-scale industrialization value.

[0017] This embodiment uses an adapter as a welding medium, and laser welding is applied to the adapter. This avoids the laser directly ablating and breaking down the ultra-thin conductive layer and intermediate insulating layer of the composite current collector, fundamentally solving the industry problem that composite current collectors cannot be directly laser welded.

[0018] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0019] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which: In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0020] Figure 1 A schematic diagram of the structure of the electrode provided in the embodiments of this disclosure is shown. Figure 1 ; Figure 2 A schematic diagram of the structure of the electrode provided in the embodiments of this disclosure is shown. Figure 2 ; Figure 3 A schematic diagram of the electrode processing procedure provided in this embodiment is shown. Figure 1 ; Figure 4 A schematic diagram of the electrode processing procedure provided in this embodiment is shown. Figure 2 ; Figure 5 A schematic diagram of the electrode processing procedure provided in this embodiment is shown. Figure 3 ; Figure 6 A schematic diagram of the structure of the electrode provided in the embodiments of this disclosure is shown. Figure 3 ; Figure 7 A schematic diagram of the structure of the electrode provided in the embodiments of this disclosure is shown. Figure 4 .

[0021] The following are the labels in the diagram: 1. Composite current collector; 11. First conductive layer; 12. Second conductive layer; 13. Insulating layer; 2. Adapter; 21. Sub-Adapter; 22. Welding part; 3. Ultrasonic roll welding equipment; 31. Welding head. Detailed Implementation

[0022] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0023] Batteries not only serve as the operating power source for vehicles but also as the driving power source, replacing or partially replacing fuel or natural gas to provide propulsion. A battery can include a casing and individual battery cells, with the cells housed within the casing. The casing, which houses the battery cells, can have various structures. A battery cell can be single or multiple. If multiple cells are present, they can be connected in series, parallel, or a combination thereof. A combination thereof means that multiple cells are connected in both series and parallel configurations. Multiple battery cells can be directly connected in series, parallel, or a combination thereof, and then the entire assembly is housed within the casing. Alternatively, multiple battery cells can first be connected in series, parallel, or a combination thereof to form modules, and then these modules can be connected in series, parallel, or a combination thereof to form a single unit housed within the casing. Batteries can also include other structures; for example, multiple battery cells can be electrically connected via a busbar to achieve parallel, series, or combination connections.

[0024] Each battery cell can be a lithium-ion battery, such as a secondary or primary battery; it can also be a lithium-sulfur battery, sodium-ion battery, or magnesium-ion battery, but is not limited to these. A battery cell refers to the smallest unit that makes up a battery.

[0025] A single battery cell may include a casing, an electrode assembly, and an electrolyte, with both the electrode assembly and the electrolyte housed within the casing. The electrode assembly may consist of a positive electrode, a negative electrode, and a separator. The separator is positioned between the positive and negative electrode to provide insulation. The electrode assembly may be a wound structure or a stacked structure; this application is not limited to these. The negative electrode includes a negative current collector and a negative active material layer, the latter comprising a negative active material. The negative active material includes at least one of graphite, silicon, a silicon alloy, or a tin alloy. The positive electrode includes a positive current collector and a positive active material layer, the latter comprising a positive active material. Both the negative and positive current collectors may be composite current collectors.

[0026] The composite current collector 1 includes an insulating layer 13 and a conductive layer. The conductive layer is disposed on both sides of the insulating layer 13 along its thickness direction. Perpendicular to the thickness direction of the composite current collector 1, the composite current collector 1 includes an active material support region and a tab connection region. Since the insulating layer 13 in the edge tab region is an insulator, traditional ultrasonic direct welding methods cannot weld the upper and lower conductive layers. Therefore, there is an urgent need for a technical solution that can efficiently and reliably laser weld the composite current collector 1 in large cylindrical all-tab batteries, enabling the large-scale application of the composite current collector 1 in large cylindrical batteries while ensuring low impedance, high stability, and high mechanical strength of the connection.

[0027] Combination Figure 1 and Figure 2 As shown, the electrode provided in this embodiment includes a composite current collector 1 and an adapter 2. The composite current collector 1 includes a first end located on one side of the composite current collector 1, which is typically a tab connection area. The adapter 2 is disposed at the first end of the composite current collector 1, and at least a portion of the adapter 2 overlaps with the first end. The adapter 2 and the first end are metallurgically bonded by ultrasonic roll welding. The metallurgical bond between the adapter 2 and the composite current collector 1 formed by ultrasonic roll welding results in no incomplete welding at the interface and no risk of aging. The mechanical connection strength and conductivity stability are significantly better than conductive adhesive bonding and ordinary ultrasonic spot welding, meeting the requirements for high current and high reliability connection of large cylindrical full-tab electrodes. Ultrasonic roll welding is a solid-state cold welding with a very small heat-affected zone, which does not damage the insulation layer 13 of the composite current collector 1. Laser welding is concentrated on the adapter 2, reducing the risk of welding thermal runaway and improving the overall safety and cycle life of the battery.

[0028] The area where adapter 2 is located constitutes the laser welding zone for laser welding with the electrode tab. The laser welding zone is a standard pure metal area, which can directly use the existing mature laser welding process and equipment for large cylindrical batteries without modifying the back-end production line. The process is simple, efficient, and has value for large-scale industrialization.

[0029] First, the adapter 2 forms a dedicated laser welding zone, ensuring that laser welding is applied only to the adapter 2. This avoids direct laser action on the composite current collector 1, preventing ablation, breakdown, or spatter, fundamentally solving the technical challenge of directly laser welding the composite current collector 1 and significantly improving connection reliability. Second, the adapter 2 and the composite current collector 1 are metallurgically bonded, resulting in low interface contact resistance, high mechanical connection strength, and good long-term stability. This effectively overcomes the shortcomings of conductive adhesive bonding, such as easy aging and increased resistance, as well as the small area and insufficient strength of ordinary ultrasonic spot welding. Third, the laser welding zone is a pure metal welding area adapted to existing processes, directly compatible with existing laser welding production lines for large cylindrical batteries. It requires no major modifications to backend equipment, resulting in a simple process, high production efficiency, and promising industrialization prospects. Furthermore, the ultrasonic roll welding has a minimal heat-affected zone, preventing damage to the insulating layer 13 of the composite current collector 1, which is beneficial for improving battery safety and cycle life. Simultaneously, the structure of the adapter 2 can be flexibly adjusted to accommodate various tab structures, such as all-tab and multi-tab designs, making it widely applicable.

[0030] The shape (e.g., strip, sheet), size, and welding pattern (single strip, double strip, mesh) of adapter 2 can be flexibly designed according to the current magnitude and mechanical strength requirements to meet the current distribution needs of different areas of the full tab. Through flexible design, adapter 2 can be adapted to different tab structures such as full tab / multi-tab, flattened / stacked, etc., to meet the diverse design and current distribution requirements of large cylindrical batteries.

[0031] In some specific implementation methods, combined with Figure 1 and Figure 3 and Figure 4 As shown, the adapter 2 is a continuous metal strip, the same length as the composite current collector 1. Setting the adapter 2 as a continuous metal strip of the same length as the composite current collector 1 enables continuous bonding and ultrasonic roll welding between the adapter 2 and the composite current collector 1 along their entire length. This effectively improves the uniformity and integrity of their connection, avoiding problems such as localized stress concentration and unstable contact caused by segmented structures. Simultaneously, the continuous metal strip can form a full-length laser welding zone, meeting the connection requirements of large cylindrical all-tab batteries for large-area, low-impedance, and uniform current conduction. This improves the uniformity of current distribution and structural stability of the electrode sheets, and facilitates continuous roll-to-roll production, thus improving processing efficiency and product consistency.

[0032] In some specific implementation methods, such as Figure 2As shown, the adapter 2 includes multiple sub-adapters 21, which are arranged at equal or non-equal intervals at the first end. The adapter 2's structure, with multiple sub-adapters 21 arranged at equal or non-equal intervals, allows for flexible adjustment of the number, spacing, and arrangement of the sub-adapters 21 according to the current distribution, welding points, and stress requirements of the large cylindrical battery tab area. This reduces the amount of metal material used, lightens the overall weight of the electrode, and lowers costs while ensuring welding strength and conductive paths. Simultaneously, the spaced sub-adapters 21 avoid stress concentration and winding deformation problems caused by continuous metal strips, improving the structural stability and yield of the electrode during winding and assembly. Furthermore, it can adapt to different full-tab / multi-tab welding processes, forming multi-point laser welding areas as needed, balancing connection reliability and process flexibility.

[0033] In some specific implementation methods, such as Figure 6 As shown, the composite current collector 1 includes a first conductive layer 11, a second conductive layer 12, and an insulating layer 13 disposed between the first conductive layer 11 and the second conductive layer 12; the adapter 2 is connected to one of the first conductive layer 11 and the second conductive layer 12 by ultrasonic roll welding. Connecting the adapter 2 to one of the first conductive layer 11 or the second conductive layer 12 of the composite current collector 1 by ultrasonic roll welding achieves a stable solid-state metallurgical bond between the adapter 2 and the conductive layer without damaging the intermediate insulating layer 13, ensuring a smooth conductive path and effectively avoiding risks such as the insulating layer 13 melting due to heat or short circuits during welding. Furthermore, this connection method only welds one side of the conductive layer, simplifying process control, concentrating the heat-affected zone, reducing the difficulty of welding parameter adjustment, improving the consistency and yield of mass production, and adapting to the differentiated welding requirements of conductive layers with different positive and negative electrode materials, thus broadening its applicability.

[0034] In some specific implementation methods, such as Figure 7 As shown, there are two adapters 2, one of which is ultrasonically welded to the first conductive layer 11, and the other is ultrasonically welded to the second conductive layer 12. The two adapters 2, each ultrasonically welded to the first conductive layer 11 and the second conductive layer 12 of the composite current collector 1 respectively, enable efficient conductive lead-out from both conductive layers simultaneously, significantly reducing the overall contact resistance of the electrode and improving the uniformity of current conduction under high-current charging and discharging conditions. The two adapters 2 form metallurgical bonding interfaces with their corresponding conductive layers, resulting in higher connection strength and shorter conductive paths, avoiding current deviation and localized heating problems caused by single-sided connections. Simultaneously, the double-sided welding structure improves the structural rigidity of the electrode ends, reduces deformation and wrinkles during winding and assembly, and further enhances the battery structural stability and cycle life.

[0035] In some specific implementation methods, combined with Figure 1 and Figure 3As shown, ultrasonic roll welding forms a continuous linear welded portion 22, which in turn forms one or more connecting ribs. This continuous linear welded portion 22, along with the connecting ribs, enables a continuous, uniform, and large-area solid-state metallurgical bond between the adapter 2 and the composite current collector 1. This significantly improves the mechanical strength and conductivity stability of the connection interface, effectively avoiding problems such as poor contact and excessively high local resistance caused by single-point welding. The arrangement of one or more connecting ribs allows for the adjustment of the number of conductive paths and current carrying capacity as needed, balancing structural strength and conductivity efficiency to meet the high-current output requirements of large cylindrical all-tab batteries. Furthermore, the continuous linear welded portion exhibits good consistency, facilitating continuous roll-to-roll production and improving processing efficiency and product yield.

[0036] In some specific implementation methods, such as Figure 5 As shown, ultrasonic roll welding forms multiple discontinuous linear welded sections 22. This discontinuous linear welded section 22, while ensuring a stable metallurgical bond and effective conductive path between the adapter 2 and the composite current collector 1, reduces the welding time and area, lowers the risk of thermal damage to the insulation layer 13 of the composite current collector 1 due to accumulated welding heat, and further enhances the safety of the electrode structure. Simultaneously, the discontinuous linear welded sections 22 reduce stress concentration at the welding interface, improve the flexibility of the electrode ends, adapt to large cylindrical battery winding and leveling assembly processes, and reduce the risk of electrode wrinkling and tearing. Furthermore, the density and length of the welded sections 22 can be flexibly adjusted according to current carrying requirements, balancing connection reliability, process energy consumption, and production efficiency, thus improving process adaptability.

[0037] In some specific embodiments, the adapter 2 is an aluminum or copper strip with a thickness of 0.01 mm to 0.03 mm. Using an aluminum or copper strip with a thickness of 0.01 mm to 0.03 mm for the adapter 2 ensures sufficient structural strength and conductive cross-section in the laser welding area to meet the requirements of deep penetration welding and high current conduction, while also controlling the overall thickness and weight to maintain the advantages of lightweight electrode and energy density. This thickness range matches the welding performance of conventional pure metal current collectors, offering a wide laser welding process window, stable forming, and low weld penetration, effectively reducing welding spatter and defects. Simultaneously, the aluminum and copper strips are respectively compatible with the positive and negative electrode conductive layer materials, resulting in strong interfacial bonding and low contact resistance, balancing conductivity, processability, and structural reliability.

[0038] In some specific embodiments, the ultrasonic roll welding interface between the adapter 2 and the composite current collector 1 is provided with a conductive reinforcement layer, which is one of a nano-carbon layer, a silver paste layer, or a nickel plating layer. By providing a conductive reinforcement layer, the interfacial contact resistance between the adapter 2 and the conductive layer of the composite current collector 1 can be further reduced, the high current conduction capability can be improved, and the metallurgical bonding strength of the ultrasonic roll welding can be enhanced, reducing the risk of interface debonding and improving the structural stability and service life of the electrode during cyclic charging and discharging.

[0039] In some specific embodiments, the adapter 2 has a microstructured rough surface on the side facing the composite current collector 1. This microstructured rough surface can be an array of protrusions, an array of grooves, or a frosted surface, used to improve the ultrasonic roll welding bonding strength. The rough surface increases the effective contact area between the adapter 2 and the composite current collector 1, improving the efficiency of frictional heat generation and mechanical interlocking strength during ultrasonic roll welding, significantly improving the welding bond force, preventing the adapter 2 from detaching, and ensuring a more stable and uniform conductive path.

[0040] In some specific embodiments, the surface of the laser welding area is provided with an anti-spatter coating or a laser absorption layer, the thickness of which is 1μm–10μm. The laser absorption layer can improve the laser energy absorption rate, reduce the welding threshold, and reduce the heat-affected zone; the anti-spatter coating can suppress metal spatter during laser welding, preventing spatter from falling into the battery and causing micro-short circuits, thereby improving battery safety performance and welding yield.

[0041] In some specific embodiments, the thickness of the insulating layer 13 is 5μm–30μm, and the thicknesses of the first conductive layer 11 and the second conductive layer 12 are each 0.5μm–2μm. This thickness matching ensures both the insulation reliability and mechanical strength of the composite current collector 1, while maintaining the high flexibility and lightweight advantages of the ultra-thin conductive layer, adapting to the large cylindrical battery winding process, and facilitating the formation of a stable metallurgical bond by ultrasonic roll welding.

[0042] In some specific embodiments, the edge of the adapter 2 is provided with a chamfer or rounded transition structure, which can effectively reduce the sharpness of the edge of the adapter 2, avoid scratching the composite current collector 1 and the separator during the electrode winding, stacking and flattening process, reduce electrode wrinkles and damage, and improve battery assembly yield and safety reliability.

[0043] The battery provided in this disclosure includes the electrode sheet provided in this disclosure.

[0044] The electrode processing method provided in this embodiment includes the following steps: a connector 2 is provided at the first end of the composite current collector 1, such that at least part of the connector 2 overlaps with the first end; the connector 2 is rolled and ultrasonically welded onto the conductive layer on the surface of the composite current collector 1 using an ultrasonic rolling welding device 3, so that the connector 2 and the conductive layer on the surface of the composite current collector 1 form a metallurgical bond; and the connector 2 is laser welded to the electrode tab.

[0045] The electrode processing method provided in this disclosure involves setting an adapter 2 at the first end of the composite current collector 1 and achieving metallurgical bonding through ultrasonic roll welding. The adapter 2 is then laser-welded to the electrode tab. This eliminates the need for direct laser welding of the composite current collector 1 throughout the process, preventing laser ablation and breakdown of the insulating layer 13 and ultra-thin conductive layer of the composite current collector 1 from the process source, thus completely solving the industry pain point of difficulty in laser welding the composite current collector 1. The simultaneous ultrasonic roll welding and rolling process enables the adapter 2 and the conductive layer to form a stable solid-state metallurgical bond with low interface resistance, high connection strength, and no risk of incomplete welding or aging, which is superior to conductive adhesive bonding and traditional spot welding processes. This method only requires adding an ultrasonic roll welding step to the existing electrode manufacturing process, and is directly compatible with mature laser welding production lines for large cylindrical batteries. No back-end equipment modification is required. The process is simple, highly continuous, and boasts excellent production efficiency and yield, significantly improving the stability of electrode manufacturing and its adaptability to battery industrialization.

[0046] In some specific embodiments, the welding head 31 of the ultrasonic roll welding equipment 3 is a circular rotatable structure. The welding head 31 rotates synchronously with the conveyor belt direction of the composite current collector 1 and the adapter 2, so that the welding head 31 welds the first end of the composite current collector 1 to the adapter 2 during the rotation process. The ultrasonic roll welding equipment 3 adopts a circular rotatable welding head 31, and the welding head 31 rotates synchronously with the conveyor belt direction of the composite current collector 1 and the adapter 2. This enables dynamic, stable, and scratch-free welding operations during continuous conveyor belt movement, avoiding damage such as hard friction, wrinkles, and tears caused by fixed welding heads to the electrode sheets, and significantly improving the electrode sheet processing yield. The synchronous rotation enables continuous and high-speed roll-to-roll production, greatly improving the electrode sheet processing efficiency. At the same time, the pressure distribution of the rotating welding head 31 is uniform, which makes the force between the adapter 2 and the composite current collector 1 consistent, and the welding interface more uniform and stable, effectively improving the metallurgical bonding quality and connection reliability, and adapting to the needs of large-scale and high-efficiency manufacturing of large cylindrical battery electrodes.

[0047] In some specific embodiments, the first end of the composite current collector 1 is subjected to plasma cleaning or corona treatment before ultrasonic roll welding to remove the surface oxide layer, oil and dust, so that the surface of the composite current collector 1 is kept clean, which is conducive to the formation of a denser and more uniform metallurgical bond by ultrasonic roll welding, reducing contact resistance and improving welding consistency.

[0048] In some specific embodiments, the laser welding process includes a step prior to laser welding: pre-flattening the laser welding area of ​​the adapter 2 to ensure a welding flatness of ≤0.05mm. The flattened welding area results in more uniform laser incidence and more stable penetration, significantly improving welding strength consistency and reducing defects such as incomplete welds, missed welds, and burn-through.

[0049] In some specific embodiments, the parameters for ultrasonic roll welding are: frequency 20kHz–40kHz, pressure 0.1MPa–0.5MPa, and welding speed 1m / min–20m / min. This parameter window can adapt to adapters 2 and composite current collectors 1 of different thicknesses, ensuring welding strength while avoiding over-welding damage to the insulation layer 13, and achieving high-efficiency, high-stability roll-to-roll continuous production.

[0050] This disclosure transforms the "non-weldable" composite current collector 1 into a "weldable" structure by introducing a "metal transition zone" formed by the adapter 2 as a bridge. Ultrasonic roll welding is responsible for solving the problem of reliable connection with the composite current collector 1, while laser welding is responsible for solving the problem of strong connection with the battery structure. The two perform their respective functions, perfectly avoiding the risk of the laser directly acting on the composite current collector 1.

[0051] Ultrasonic roll welding is a solid-state welding process with a minimal heat-affected zone, preventing the melting or damage of the polymer base film of the composite current collector 1. The resulting metallurgical interface exhibits low electrical resistance, high mechanical strength, and good stability. Subsequent laser welding is performed in the pure metal region, a mature and stable process that can create a deep-penetration weld, ensuring low impedance and high strength for the overall connection.

[0052] This solution only requires adding an ultrasonic roll welding process before and after the cutting of the existing composite current collector electrode to make it fully compatible with the existing mature laser welding assembly line for large cylindrical batteries. It does not require major modifications to the back-end equipment and has great value for industrialization.

[0053] The shape (e.g., strip, sheet), size, and welding pattern (single strip, double strip, mesh) of the adapter 2 (e.g., metal transition strip) can be flexibly designed according to the current magnitude and mechanical strength requirements to meet the current distribution needs of different areas of the full electrode.

[0054] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this embodiment can be achieved, and this is not limited herein.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0056] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. An electrode sheet, characterized in that, include: Composite current collector (1) and adapter (2); The composite current collector (1) includes a first end located on one side of the composite current collector (1), and the adapter (2) is disposed at the first end of the composite current collector (1). At least a portion of the adapter (2) overlaps with the first end, and the adapter (2) and the first end are metallurgically bonded by ultrasonic roll welding. The area where the adapter (2) is located constitutes a laser welding zone for laser welding with the electrode.

2. The electrode sheet according to claim 1, characterized in that, The adapter (2) is a continuous metal strip, and the continuous metal strip is the same length as the composite current collector (1).

3. The electrode sheet according to claim 1, characterized in that, The adapter (2) includes a plurality of sub-adapters (21), which are arranged at equal or unequal intervals at the first end.

4. The electrode sheet according to claim 1, characterized in that, The composite current collector (1) includes a first conductive layer (11), a second conductive layer (12), and an insulating layer (13) disposed between the first conductive layer (11) and the second conductive layer (12); The adapter (2) is connected to one of the first conductive layer (11) and the second conductive layer (12) by ultrasonic roll welding.

5. The electrode sheet according to claim 4, characterized in that, The number of the adapter (2) is two, one of which is connected to the first conductive layer (11) by ultrasonic roll welding, and the other is connected to the second conductive layer (12) by ultrasonic roll welding.

6. The electrode sheet according to claim 1, characterized in that, The ultrasonic roll welding forms a continuous linear welded section (22), and the linear welded section (22) forms one or more connecting ribs; Alternatively, the ultrasonic roll welding forms multiple discontinuous linear welded sections (22).

7. The electrode sheet according to claim 1, characterized in that, The adapter (2) is an aluminum or copper strip with a thickness of 0.01 mm to 0.03 mm.

8. A battery, characterized in that, Includes the electrode sheet as described in any one of claims 1 to 7.

9. A method for processing an electrode sheet, characterized in that, Includes the following steps: A connector (2) is provided at the first end of the composite current collector (1) such that at least part of the connector (2) overlaps with the first end; The adapter (2) is rolled and ultrasonically welded onto the conductive layer on the surface of the composite current collector (1) using an ultrasonic rolling welding device (3), so that the adapter (2) and the conductive layer on the surface of the composite current collector (1) form a metallurgical bond. The adapter (2) is laser welded to the electrode.

10. The method for processing an electrode sheet according to claim 9, characterized in that, The welding head (31) of the ultrasonic roll welding equipment (3) is a circular rotatable structure. The welding head (31) rotates synchronously with the composite current collector (1) and the adapter (2) in the direction of the conveyor belt, so that the welding head (31) welds the first end of the composite current collector (1) to the adapter (2) during the rotation process.

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