Preparation method of current collector, current collector, battery and battery processing equipment

Abstract

The invention relates to a preparation method of a current collector, the current collector, a battery and battery processing equipment. The preparation method of the current collector comprises the following steps: unwinding a substrate foil, and plating a plurality of metal layers on the surface of the substrate foil in the unwinding process so as to form a plurality of layers of metal foils on the surface of the substrate foil; stripping the multi-layer metal foil from the base foil; and cutting the stripped multi-layer metal foil to obtain the current collector. In the machining process, the base foil serves as a temporary substrate for plating of all the metal layers, additional machining is not needed to form a basic foil of the multi-layer metal foil, and the problem of strip breakage easily occurring when the basic foil is independently prepared is solved. Therefore, the metal layer which is originally used as the basic foil material can be processed to be thinner, such as below 4 microns, and the metal layer except the basic foil material can also be processed to be thinner in a similar way. By adopting the preparation method, the current collector with the thickness as low as 4 microns can be processed, and the bottleneck that the thickness of the current collector is difficult to be below 5 microns in the industry is broken through.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to methods for preparing current collectors, current collectors, batteries, and battery processing equipment. Background Technology

[0002] The current collector serves as a carrier for the positive and negative electrode active materials of the battery cell and also plays a role in electron transport. It is an important component of the battery cell, and the density and thickness of the current collector directly affect the energy density of the battery cell.

[0003] Current collectors typically use copper foil as the base foil, and then plate other metal layers on the base foil. In traditional current collector manufacturing processes, the base foil is usually processed on a foil-making machine. Due to the limitations of the foil-making machine's manufacturing process, if the base foil is too thin, it is prone to breakage. Therefore, the finished base foil is too thick, resulting in current collectors with two or more layers being too thick overall. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for preparing a current collector, a current collector, a battery, and battery processing equipment, which solves the problem that the base foil is prone to breakage during the current collector processing, so as to be able to process ultra-thin current collectors.

[0005] In a first aspect, this application provides a method for preparing a current collector, the method comprising:

[0006] The substrate foil is unwound, and during the unwinding process, multiple metal layers are deposited on the surface of the substrate foil to form a multilayer metal foil on the surface of the substrate foil.

[0007] Peel the multilayer metal foil from the base foil;

[0008] The stripped multilayer metal foil is cut to obtain the current collector.

[0009] By sequentially depositing various metal layers onto a base foil, and then peeling the multiple metal layers off the base foil as a whole, the desired multilayer metal foil is obtained. The multilayer metal foil is then cut to obtain the current collector. During the processing, the base foil serves as a temporary substrate for the deposition of each metal layer, eliminating the need for additional processing of the base foil that constitutes the multilayer metal foil, thus avoiding the strip breakage problem that easily occurs when the base foil is prepared alone.

[0010] In one embodiment, prior to the step of unwinding the substrate foil and depositing multiple metal layers on the surface of the substrate foil during the unwinding process to form a composite coating on the surface of the substrate foil, the method further includes the step of:

[0011] The surface of the substrate foil is oxidized to generate a metal oxide layer.

[0012] By oxidizing the surface of the substrate foil to form a metal oxide layer, the barrier effect is improved, thereby weakening the bonding force between the multilayer metal foil and the substrate foil, thus reducing the difficulty of subsequent peeling of the multilayer metal foil.

[0013] In one embodiment, prior to the step of unwinding the substrate foil and depositing multiple metal layers on the surface of the substrate foil during the unwinding process to form a multilayer metal foil on the surface of the substrate foil, the method further includes the step of:

[0014] An insulating layer is disposed on one surface of a substrate foil, while the other surface of the substrate foil remains conductive.

[0015] By setting an insulating layer on one surface of a base foil, multiple layers of metal foil are processed only on the conductive surface.

[0016] In one embodiment, prior to the step of unwinding the substrate foil and depositing multiple metal layers on the surface of the substrate foil during the unwinding process to form a multilayer metal foil on the surface of the substrate foil, the method further includes the step of:

[0017] This ensures that both surfaces of the substrate foil remain conductive.

[0018] By making both surfaces of the substrate foil conductive, multiple layers of metal foil can be processed on both surfaces of the substrate foil to achieve higher processing efficiency.

[0019] In one embodiment, the thickness of the substrate foil is set to 4μm-20μm. Since the substrate foil only serves as a temporary substrate and does not constitute the structure of a multilayer metal foil, it does not affect the thickness of the multilayer metal foil. Therefore, a thicker substrate foil can be used to ensure structural strength, thereby ensuring stability and processing quality during subsequent metal layer processing.

[0020] In one embodiment, the thickness of the substrate foil is set to be in the range of 5 μm to 15 μm.

[0021] In one embodiment, the substrate foil is constructed of stainless steel foil, titanium foil, nichrome foil, or nickel foil. Stainless steel foil, titanium foil, nichrome foil, and nickel foil, among other metal foils, have high structural strength and readily form an oxide layer on their surface, eliminating the need for additional special oxidation treatment. Furthermore, the adhesion between the oxide layer and the metal layer is weak, allowing the metal layer to be easily peeled off from the oxide layer surface, thus ensuring smooth removal of the metal layer from the substrate foil.

[0022] In one embodiment, the step of unwinding the substrate foil and depositing multiple metal layers on the surface of the substrate foil during the unwinding process to form a multilayer metal foil on the surface of the substrate foil specifically includes:

[0023] Multiple metal layers are sequentially deposited on the base foil, and the foil is wound up after all metal layers have been deposited.

[0024] By sequentially depositing multiple metal layers onto the base foil, the number of winding and unwinding operations of the base foil can be minimized, which helps to improve operational efficiency.

[0025] In one embodiment, after the step of peeling the multilayer metal foil from the substrate foil, the step further includes:

[0026] Antioxidant treatment is applied to the stripped multilayer metal foil.

[0027] The corrosion resistance of the current collector is improved by subjecting the stripped multilayer metal foil to an anti-oxidation treatment.

[0028] In one embodiment, after the step of performing an anti-oxidation treatment on the stripped multilayer metal foil, the method further includes the step of:

[0029] The multilayer metal foil, after anti-oxidation treatment, is then dried. This can be done using methods such as blowing air or heating.

[0030] In one embodiment, after the step of peeling the multilayer metal foil from the substrate foil, the step further includes:

[0031] The stripped multi-layer metal foil is rolled up for easy storage and transportation.

[0032] In one embodiment, after the step of peeling the multilayer metal foil from the substrate foil, the step further includes:

[0033] The base foil is wound up.

[0034] The base foil can be recycled by winding it up.

[0035] Secondly, this application provides a current collector, which is processed by the current collector preparation method described above. The current collector includes multiple metal layers stacked sequentially, and the total thickness of the multiple metal layers is ≤5μm.

[0036] In one embodiment, the thickness of the thickest metal layer among the multiple metal layers is ≤4μm.

[0037] Thirdly, this application provides a battery, which includes the current collector as described above.

[0038] Fourthly, this application provides a battery processing apparatus for processing a current collector using the above-described current collector preparation method. The battery processing apparatus includes an electroplating device and a stripping device. The electroplating device is used to continuously deposit multiple layers of metal on a substrate foil, and the stripping device is used to strip the multiple layers of metal foil from the substrate foil.

[0039] In one embodiment, the electroplating apparatus includes:

[0040] Multiple electroplating tanks are connected in series to hold the plating solution.

[0041] In one embodiment, the stripping device includes:

[0042] At least one stripping roller, through which a base foil coated with multiple layers of metal foil is wound;

[0043] At least two take-up rollers, each taking up the base foil and the multilayer metal foil output from the stripping roller. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the current collector structure provided in one embodiment of this application.

[0045] Figure 2 This is a schematic diagram of a substrate foil coated with a current collector in one embodiment of this application.

[0046] Figure 3 This is a flowchart of a method for preparing a current collector provided in one embodiment of this application.

[0047] Figure 4 This is a detailed flowchart of the current collector preparation method provided in one embodiment of this application.

[0048] Figure 5 This is a schematic diagram of the electroplating apparatus provided in one embodiment of this application.

[0049] Figure 6 This is a schematic diagram of the structure of the stripping device provided in one embodiment of this application.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Substrate foil;

[0052] 2. Current collector; 21. X metal layer; 22. Y metal layer; 23. Z metal layer;

[0053] 3. Electroplating equipment; 31. Electroplating tank; 32. Guide rollers;

[0054] 4. Base material roller; 6. Transition roller;

[0055] 7. Peeling device; 71. First peeling roller; 72. Second peeling roller; 73. First tension roller; 74. Second tension roller; 75. Third tension roller; 76. First take-up roller; 77. Second take-up roller; 78. Third take-up roller. Detailed Implementation

[0056] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0057] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0058] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0059] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0060] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0061] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0062] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to 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 limitations on the embodiments of this application.

[0063] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0064] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0065] Current collectors are a crucial component of battery cells. As carriers of the active materials in the positive and negative electrodes, they play a vital role in electron transport. The density and thickness of the current collector directly affect the energy density of the battery cell. Therefore, research on reducing the thickness of current collectors has been ongoing in this field. However, due to the inherent low flexibility of metals, reducing the thickness to a certain extent significantly increases processing difficulty and reduces yield.

[0066] Battery cells typically use copper foil as the anode current collector. However, due to limitations in copper foil's strength, elongation, stress deformation, and corrosion resistance, copper foil cannot meet the specific requirements of battery cells for high strength, high elongation, high corrosion resistance, and high conductivity. Therefore, special functional plating layers need to be electroplated onto the copper foil surface. In related technologies, the finished current collector adopts a three-layer structure of X+Y+Z, where the middle Y layer is generally a copper layer, and the surface X and Z layers are generally chromium or nickel layers.

[0067] This application notes that the fabrication of ultrathin current collectors is primarily limited by the intermediate copper layer. In related technologies, during current collector fabrication, a copper layer is first deposited using a foil plating machine. During foil plating, the copper layer is formed on the plating roller and then peeled off. The thickness of the copper layer must be at least 4 μm; otherwise, insufficient strength will lead to strip breakage. Even using metals other than copper, it is difficult to reduce the thickness of the intermediate layer to below 4 μm. With a copper layer thickness ≥ 4 μm, after plating other metal layers on its surface, the overall thickness of the current collector reaches at least 5 μm. For three-layer current collectors, it is difficult to control the thickness below 5 μm.

[0068] To address the issue of tape breakage during the peeling of the intermediate X layer, the applicant, after in-depth consideration, developed a method for preparing the current collector. This method utilizes a substrate foil as an auxiliary tooling to deposit multiple metal layers of the current collector onto the substrate foil. After all metal layers are deposited, the entire current collector is peeled off from the substrate foil to obtain a multi-layered metal foil. Subsequently, the multi-layered metal foil is cut to obtain the current collector of the required size. This manufacturing process eliminates the need to peel off individual metal layers during the current collector preparation process; therefore, there are no strength requirements for the thickness of individual metal layers. The overall thickness and strength of the current collector only need to meet the peeling requirements. Generally, an overall thickness of 4 μm is sufficient for the current collector, and the thickness of each metal layer can be flexibly set according to requirements.

[0069] See Figure 1 This embodiment provides a current collector 2 and a battery including the current collector 2. Figure 1 A schematic diagram of the current collector 2 provided in one embodiment of this application is shown. The current collector 2 includes multiple sequentially stacked metal layers. By using the preparation method provided in this application, the total thickness of the multiple metal layers can reach ≤5μm, thus preparing an ultrathin current collector 2. Among the multiple metal layers, the thickness of the thickest metal layer can reach ≤4μm.

[0070] Specifically, this application provides a three-layer current collector with an X+Y+Z structure. The three layers are an X metal layer 21, a Y metal layer 22, and a Z metal layer 23. The Y metal layer 22 represents the middle layer, and the X metal layer 21 and Z metal layer 23 represent the surface layers on both sides of the Y metal layer 22. The thicknesses of the X metal layer 21, Y metal layer 22, and Z metal layer 23 are not limited. For example, the thickness of each layer of the current collector can be set to 1μm+3μm+1μm, 0.5μm+3μm+0.3μm, 1μm+2μm+1μm, etc. Of course, the current collector 2 provided in this application can also be a two-layer or three-layer structure. When the number of layers is large, the overall thickness of the current collector 2 can be controlled by reducing the thickness of each metal layer, thereby meeting the processing requirements of the ultra-thin current collector 2.

[0071] Please see Figure 2 and Figure 3 , Figure 2 This illustration shows a schematic diagram of a substrate foil 1 coated with a current collector 2, provided in one embodiment of this application. Figure 3 A flowchart of a method for preparing a current collector according to an embodiment of this application is shown. This application provides a method for preparing a current collector, which includes the following steps:

[0072] S1: Unwind the substrate foil 1. During the unwinding process, deposit multiple metal layers on the surface of the substrate foil 1 to form a multilayer metal foil on the surface of the substrate foil 1.

[0073] S2: Peel the multilayer metal foil from the substrate foil 1;

[0074] S3: Cut the stripped multilayer metal foil to obtain current collector 2.

[0075] Specifically, the obtained current collector 2 is used in the battery cell as a carrier for the positive and negative electrode active materials, playing a crucial role in electron transport. The substrate foil 1 serves as a temporary substrate and does not constitute part of the current collector 2. It can be made of high-strength metal foils such as stainless steel foil, titanium foil, nickel-chromium foil, or nickel foil. The multilayer metal layers can be set to two, three, or more layers. The materials used for each metal layer can be the same or different. Each metal layer can specifically be a copper layer, a chromium layer, or a nickel layer.

[0076] The current collector preparation method proposed in this application involves sequentially depositing various metal layers onto a substrate foil 1, and then peeling the multiple metal layers off the substrate foil 1 as a whole to obtain the desired multilayer metal foil. The multilayer metal foil is then cut to obtain the current collector 2. During the processing, the substrate foil 1 serves as a temporary substrate for the deposition of each metal layer, eliminating the need for additional processing of the base foil constituting the multilayer metal foil, thus avoiding the strip breakage problem that easily occurs when the base foil is prepared alone. Therefore, the metal layers that originally served as the base foil can be processed to a relatively thin thickness, such as below 4 μm. Similarly, the metal layers other than the base foil can also be processed to a relatively thin thickness. Using this preparation method, current collectors 2 with a thickness as low as 4 μm can be processed, overcoming the bottleneck in the industry where it is difficult to achieve a thickness of current collectors 2 below 5 μm.

[0077] It should be noted that there are no restrictions on the specific method of depositing each metal layer on the substrate foil 1. Traditional equipment such as roller electroplating line, double-sided electroplating line, vapor deposition equipment and magnetron sputtering can all be used to process each metal layer.

[0078] Optionally, the substrate foil 1 can be made of a material with high strength, minimal impact on the metal layer, and easy peeling from the metal layer, such as stainless steel foil, titanium foil, nickel-chromium foil, or nickel foil. Stainless steel foil, titanium foil, nickel-chromium foil, and nickel foil have high structural strength and readily form an oxide layer on their surface, eliminating the need for additional special oxidation treatment. Furthermore, the adhesion between the oxide layer and the metal layer is weak, making it easy for the metal layer to peel off from the oxide layer surface, thus ensuring smooth peeling of the metal layer from the substrate foil 1.

[0079] In one embodiment, to ensure the structural strength of the substrate foil 1 and prevent tape breakage during winding and unwinding, the substrate foil 1 needs to reach a certain thickness. Generally, the thickness range of the substrate foil 1 is set to 4μm-20μm, specifically, the thickness range of the substrate foil 1 is set to 5μm-15μm, preferably 10μm. Since the substrate foil 1 only serves as a temporary substrate and does not constitute the structure of a multilayer metal foil, it does not affect the thickness of the multilayer metal foil. Therefore, the substrate foil 1 can use a thicker material to ensure structural strength, thereby ensuring stability and processing quality during subsequent metal layer processing.

[0080] In one embodiment, prior to step S1, the surface of the substrate foil 1 is oxidized to form a metal oxide layer. The formation of the metal oxide layer through oxidation of the substrate foil 1 enhances the barrier effect, thereby weakening the bond between the multilayer metal foil and the substrate foil 1, thus reducing the difficulty of subsequent peeling of the multilayer metal foil.

[0081] In one embodiment, before step S1, an insulating layer is provided on one surface of the substrate foil 1, while the other surface of the substrate foil 1 remains conductive, and multiple layers of metal foil are processed only on the conductive surface.

[0082] In another embodiment, before step S1, both surfaces of the substrate foil 1 remain conductive, thereby enabling the processing of multiple layers of metal foil on both surfaces of the substrate foil 1 to achieve higher processing efficiency.

[0083] In one embodiment, please refer to Figure 4 , Figure 4 A detailed flowchart of the current collector preparation method provided in one embodiment of this application is shown. The current collector preparation method further includes step S4: winding up the substrate foil 1 coated with a metal layer. Specifically, during the metal layer coating, multiple metal layers are sequentially and continuously coated on the substrate foil 1, and the current collector is wound up after all metal layers have been coated, so as to minimize the number of winding and unwinding operations of the base foil and improve work efficiency.

[0084] In one embodiment, the method for preparing the current collector further includes step S5: subjecting the stripped multilayer metal foil to an anti-oxidation treatment to improve the corrosion resistance of the multilayer metal foil. Specifically, the multilayer metal foil is immersed in an anti-oxidation solution for anti-oxidation treatment. For multilayer metal foils made of copper or nickel, the anti-oxidation solution is generally a chromium-containing passivation solution.

[0085] In one embodiment, the method for preparing the current collector further includes step S6: drying the multilayer metal foil after anti-oxidation treatment, specifically by means of blowing air, heating, etc.

[0086] In one embodiment, in order to facilitate the storage of the prepared multilayer metal foil, the current collector preparation method further includes step S7: rolling up the peeled multilayer metal foil to facilitate storage and transportation.

[0087] In one embodiment, the method for preparing the current collector further includes step S8: peeling the multilayer metal layer from the substrate foil 1 and then winding up the substrate foil 1 so that it can be recycled.

[0088] The preparation process of the current collector provided in this embodiment is as follows:

[0089] S1: Unwind the substrate foil 1. During the unwinding process, deposit multiple metal layers on the surface of the substrate foil 1 to form a multilayer metal foil on the surface of the substrate foil.

[0090] S2: Peel the multilayer metal foil from the substrate foil 1;

[0091] S3: Cut the stripped multilayer metal foil to obtain current collector 2;

[0092] S4: Wind up the metal-coated substrate foil 1;

[0093] S5: Antioxidant treatment is applied to the stripped multilayer metal foil;

[0094] S6: Dry the multilayer metal foil after anti-oxidation treatment.

[0095] S7: Roll up the stripped multi-layer metal foil;

[0096] S8: After peeling the multilayer metal layers off the base foil 1, the base foil 1 is wound up.

[0097] The current collector preparation method proposed in this application involves sequentially depositing various metal layers onto a substrate foil 1, then peeling the multiple metal layers off the substrate foil 1 as a whole to obtain the desired multilayer metal foil. The multilayer metal foil is then cut to obtain the current collector 2. During processing, the substrate foil 1 serves as a temporary substrate for the metal layers, eliminating the need for additional processing of the base foil constituting the current collector 2, thus avoiding the breakage problem that easily occurs when the base foil is prepared separately. Anti-oxidation treatment of the peeled multilayer metal foil improves its corrosion resistance. The winding and unwinding operations of the substrate foil 1 enhance the processing continuity and convenience of the multilayer metal layers and facilitate the reuse of the substrate foil 1.

[0098] The current collector preparation method proposed in this application integrates the processing, anti-oxidation treatment and winding of multilayer metal foil into a single production line, which helps to save process switching costs and achieves high processing efficiency.

[0099] This application also provides a battery processing apparatus for processing a current collector 2 using the current collector preparation method described above. The battery processing apparatus includes an electroplating device 3 and a stripping device 7. The electroplating device 3 is used to continuously deposit multiple layers of metal onto a substrate foil 1, and the stripping device 7 is used to peel the multiple layers of metal foil off the substrate foil 1. The number of metal layers deposited on the substrate foil 1 by the electroplating device 3 can be flexibly adjusted according to the desired structure of the current collector 2. After the stripping device 7 peels the multiple layers of metal foil off the substrate foil 1, the multiple layers of metal foil are separated from the substrate foil 1 as a whole, forming the current collector 2. After the substrate foil 1 is separated from the multiple layers of metal foil, it can be recycled as a temporary substrate for the next processing of the current collector 2.

[0100] like Figure 5 As shown, Figure 5 A schematic diagram of the electroplating apparatus 3 provided in an embodiment of this application is shown. The electroplating apparatus 3 includes multiple electroplating tanks 31 arranged in series. The electroplating tanks 31 are used to hold plating solutions, and each of the multiple electroplating tanks 31 contains a plating solution for forming each metal layer. The substrate foil 1 is wound onto the substrate material roller 4. After being released from the substrate material roller 4, it is guided by multiple guide rollers 32 and sequentially passes through each electroplating tank 31 for immersion to sequentially form the aforementioned X metal layer 21, Y metal layer 22, and Z metal layer 23. Then, the substrate foil 1 plated with each metal layer is wound onto the transition winding roller 6. The specific number of electroplating tanks 31 is determined according to the number of each metal layer. When each metal layer includes three layers (X metal layer 21, Y metal layer 22, and Z metal layer 23), three electroplating tanks 31 are provided. When each metal layer has more than three layers, the number of electroplating tanks 31 can be increased accordingly.

[0101] like Figure 6 As shown, Figure 6A schematic diagram of the peeling device 7 provided in one embodiment of this application is shown. The peeling device 7 includes at least one peeling roller and at least two take-up rollers. The roll material (i.e., the base foil 1 coated with multilayer metal foil) released from the transition roll 6 passes around the peeling roller, and the at least two take-up rollers respectively take up the base foil 1 and the multilayer metal foil output from the peeling roller to peel the base foil 1 and the multilayer metal foil apart. When the base foil 1 is coated with current collectors 2 on both sides, three take-up rollers are provided. One take-up roller takes up the base foil 1, and the other two take-up rollers take up the multilayer metal foil on the two sides respectively. The diameter of the peeling roller can be set to be larger than the diameter of the take-up roller. By setting the peeling roller to a larger diameter, it is easier to transport the roll material, while setting the take-up roller to a smaller diameter is beneficial to reduce the size of the finished product after winding, which is convenient for storage and transportation.

[0102] In one embodiment, such as Figure 6 As shown, the stripping roller includes a first stripping roller 71 and a second stripping roller 72. The second stripping roller 72 is located on the right side of the first stripping roller 71, and the transition roll 6 is located on the left side of the first stripping roller 71. The roll material released by the transition roll 6 passes over the upper side of the first stripping roller 71 and then passes over the lower side of the second stripping roller 72.

[0103] The take-up rollers include a first take-up roller 76, a second take-up roller 77, and a third take-up roller 78. The first take-up roller 76 is disposed above the first peeling roller 71 and is used to take up the multilayer metal foil on the upper surface of the substrate foil 1. The second take-up roller 77 is disposed below the second peeling roller 72 and is used to take up the multilayer metal foil on the lower surface of the substrate foil 1. The third take-up roller 78 is disposed to the right of the second peeling roller 72 and is used to take up the substrate foil 1.

[0104] To ensure effective winding, a first tension roller 73 is positioned between the first take-up roller 76 and the first stripping roller 71. The multi-layered metal foil is wound around the first tension roller 73 before being wound onto the first take-up roller 76. The first tension roller 73 guides and tensions the multi-layered metal foil, ensuring a relatively smooth and tight winding process on the first take-up roller 76. The gap between the first tension roller 73 and the first stripping roller 71 can be set to be equal to the overall thickness of the coil released from the transition roller 6.

[0105] The diameter of the first tensioning roller 73 is much smaller than that of the first peeling roller 71, which is sufficient to tension and guide the multi-layer metal foil.

[0106] A second tension roller 74 is disposed between the second take-up roller 77 and the second peeling roller 72. The multilayer metal foil is wound around the second tension roller 74 and then onto the second take-up roller 77. By setting the second tension roller 74 to guide and tension the multilayer metal foil, it is ensured that the multilayer metal foil is wound relatively flat and not loose on the second take-up roller 77. Since the multilayer metal foil on the upper surface has been peeled and wound onto the first take-up roller 76, the gap between the second tension roller 74 and the second peeling roller 72 can be set to be equal to the sum of the thicknesses of the base foil 1 and the multilayer metal foil on the lower surface.

[0107] The diameter of the second tensioning roller 74 is much smaller than that of the second stripping roller 72, which is sufficient to tension and guide the multi-layer metal foil.

[0108] A third tension roller 75 is disposed between the third take-up roller 78 and the second peeling roller 72. The substrate foil 1 is wound around the third tension roller 75 and then onto the third take-up roller 78. By setting the third tension roller 75, the substrate foil 1 is guided and tensioned, thereby ensuring that the substrate foil 1 is wound relatively flat and not loose on the third take-up roller 78. Specifically, the gap between the third tension roller 75 and the second peeling roller 72 can be set to be equal to the thickness of the substrate foil 1, and the diameter of the third tension roller 75 is much smaller than the diameter of the second peeling roller 72.

[0109] 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.

[0110] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a current collector, characterized in that, The method for preparing the current collector includes: The substrate foil is unwound, and during the unwound process, multiple metal layers are deposited on the surface of the substrate foil to form a multilayer metal foil on the surface of the substrate foil. Peel the multilayer metal foil from the substrate foil; The stripped multilayer metal foil is cut to obtain a current collector.

2. The method for preparing a current collector according to claim 1, characterized in that, Before the step of unwinding the substrate foil, during which multiple metal layers are deposited on the surface of the substrate foil to form a composite coating on the surface of the substrate foil, the method further includes the following step: The surface of the substrate foil is oxidized to generate a metal oxide layer.

3. The method for preparing a current collector according to claim 1, characterized in that, Before the step of unwinding the substrate foil, during which multiple metal layers are deposited on the surface of the substrate foil to form a multilayer metal foil on the surface of the substrate foil, the method further includes the following step: An insulating layer is disposed on one surface of the substrate foil, while the other surface of the substrate foil remains conductive.

4. The method for preparing a current collector according to claim 1, characterized in that, Before the step of unwinding the substrate foil, during which multiple metal layers are deposited on the surface of the substrate foil to form a multilayer metal foil on the surface of the substrate foil, the method further includes the following step: This ensures that both surfaces of the substrate foil remain conductive.

5. The method for preparing a current collector according to claim 1, characterized in that, The thickness of the substrate foil is set to 4μm-20μm.

6. The method for preparing a current collector according to claim 5, characterized in that, The thickness of the substrate foil is set to be between 5μm and 15μm.

7. The method for preparing a current collector according to claim 1, characterized in that, The base foil is constructed of stainless steel foil, titanium foil, nickel-chromium foil, or nickel foil.

8. The method for preparing a current collector according to claim 1, characterized in that, The step of unwinding a substrate foil, during which multiple metal layers are deposited on the surface of the substrate foil to form a multilayer metal foil on the surface of the substrate foil, specifically includes: Multiple metal layers are sequentially deposited on the base foil, and the foil is wound up after all the metal layers have been deposited.

9. The method for preparing a current collector according to any one of claims 1-8, characterized in that, Following the step of peeling the multilayer metal foil from the substrate foil, the method further includes the step of: The stripped multilayer metal foil is subjected to an antioxidant treatment.

10. The method for preparing a current collector according to claim 9, characterized in that, Following the step of performing an anti-oxidation treatment on the stripped multilayer metal foil, the method further includes the following step: The multilayer metal foil, after anti-oxidation treatment, is then dried.

11. The method for preparing a current collector according to claim 9, characterized in that, Following the step of peeling the multilayer metal foil from the substrate foil, the method further includes the step of: The stripped multilayer metal foil is rolled up.

12. The method for preparing a current collector according to any one of claims 1-8, characterized in that, Following the step of peeling the multilayer metal foil from the substrate foil, the method further includes the step of: The substrate foil is wound up.

13. A current collector, characterized in that, The current collector is processed using the current collector preparation method according to any one of claims 1-12, and the current collector comprises a plurality of sequentially stacked metal layers, wherein the total thickness of the plurality of metal layers is ≤5μm.

14. The current collector according to claim 13, characterized in that, Of the multiple metal layers, the thickness of the metal layer with the largest thickness is ≤4μm.

15. A battery, characterized in that, The battery includes the current collector as described in claim 13 or 14.

16. A battery processing apparatus, characterized in that, The battery processing equipment is used to process the current collector using the current collector preparation method as described in any one of claims 1-12. The battery processing equipment includes an electroplating device and a stripping device. The electroplating device is used to continuously deposit multiple layers of the metal layer on the substrate foil, and the stripping device is used to strip the multiple layers of metal foil from the substrate foil.

17. The battery processing equipment according to claim 16, characterized in that, The electroplating apparatus includes: Multiple electroplating tanks are connected in series to hold the plating solution.

18. The battery processing equipment according to claim 16, characterized in that, The stripping device includes: At least one stripping roller, the substrate foil coated with the multilayer metal foil is wound around the stripping roller; At least two take-up rollers, each of which takes up the base foil and the multilayer metal foil output from the stripping roller.

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