Corrosion roller, corrosion apparatus, metal layer and processing method therefor, current collector, electrode sheet, electrode assembly, secondary battery and electric device

Abstract

A corrosion roller (100), a corrosion apparatus, a metal layer (415) and a processing method therefor, a current collector (500), an electrode sheet, an electrode assembly (413), a secondary battery (41) and an electric device (400). A conveying channel (11) is arranged and extends inside a roller body (10) in the direction of an axis (13); and a corrosive liquid in the conveying channel (11) is conveyed into a corrosion part (20) through a discharging hole (12), and is then discharged to the outside of the corrosion roller (100) by means of the corrosion part (20). When the metal layer (415) is corroded, the corrosive liquid can be output to the corrosion part (20) when the corrosion part (20) comes into contact with the metal layer (415), so as to effectively corrode a surface of the metal layer (415).

Description

Etching roller, etching equipment, metal layer and processing method thereof, current collector, pole piece, electrode assembly, secondary battery and electrical device

[0001] Related applications

[0002] This application claims priority to Chinese patent application number 2023116067636, filed on November 27, 2023, entitled “Etching roller, etching equipment, metal layer and processing method thereof, current collector, pole piece, electrode assembly, secondary battery and electrical device,” the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present invention relates to the technical field of battery preparation, in particular to an etching roller, etching equipment, a metal layer and a processing method thereof, a current collector, a pole piece, an electrode assembly, a secondary battery and an electrical device. Background Art

[0004] Lithium-ion batteries are widely used in electric vehicles and consumer electronics due to their high energy density, high output power, long cycle life, and low environmental impact. The pole piece, a key component in a lithium-ion battery, typically consists of a current collector and an active layer disposed on a metal layer within the current collector. To ensure a bond between the metal layer and the active layer, the surface of the metal layer is roughened. However, limitations in the design of conventional roughening equipment lead to insufficient bonding between the active layer and the metal layer, compromising battery reliability.

[0005] Summary of the Invention

[0006] Based on this, it is necessary to provide a corrosion roller, corrosion equipment, metal layer and its processing method, current collector, pole piece, electrode assembly, secondary battery and electrical device to improve the corrosion effect, enhance the bonding force on the metal layer, and thus improve the reliability of the battery.

[0007] In the first aspect, the present application proposes an etching roller, which includes: a roller body, which is provided with a conveying channel extending along its own axial direction; a corrosion portion, which is provided on the roller body, and a discharge hole is provided on the inner wall of the conveying channel, which extends to the corrosion portion and is used on the corrosion portion to communicate with the outside of the etching roller.

[0008] The aforementioned etching roller features a delivery channel extending along the roller's axis. The etching liquid in the delivery channel is delivered to the etching section through a discharge hole, where it is then discharged from the etching section to the outside of the etching roller. This allows the etching section to deliver the etching liquid to the metal layer upon contact during etching, effectively etching the metal surface. Because the etching liquid is delivered from the inside of the etching roller to the outside, ultimately arriving at the etching section, it not only achieves targeted etching but also facilitates precise control of the liquid delivery volume, resulting in more uniform and reliable etching of the metal layer, improved corrosion results, and enhanced bonding strength to the metal layer, thereby enhancing battery reliability.

[0009] In some embodiments, the hole area of ​​the discharge hole is recorded as S1, where 1 mm 2 ≤S1≤10mm 2 With this design, the hole area S1 is controlled at 1mm 2 ~10mm 2 Under the premise of achieving effective roughness, it can effectively balance the smoothness of liquid discharge and corrosion cost.

[0010] In some embodiments, the hole area S1 also meets the following conditions: 3mm 2 ≤S1≤7mm 2 .

[0011] In some embodiments, the roller body has a roller surface disposed circumferentially around its axis, with at least a portion of the etching portion disposed on the roller surface; and / or, at least a portion of the etching portion is disposed within the roller body, with the end distal to the conveying channel being at least lower than the roller surface. With this design, the etching portion is strategically positioned on the roller body, facilitating effective etching of the metal layer, thereby increasing the roughness of the metal layer and enhancing bonding strength.

[0012] In some embodiments, the etching portion includes a groove disposed within the roller body, with the end remote from the delivery channel being no lower than the roller surface. The discharge hole communicates with the exterior of the etching roller through the groove. This design allows the etching liquid to be formed into a grooved structure, facilitating effective etching of the metal layer surface and improving the roughness of the metal layer.

[0013] In some embodiments, the axial dimension of the groove at the end away from the delivery channel is smaller than the axial dimension of the groove at the end closer to the delivery channel. This design facilitates centralized delivery of the etching liquid, achieving better targeted etching and improving the etching effect.

[0014] In some embodiments, the axial dimension of the groove at the end away from the delivery channel is denoted as L1, where 0.5 mm ≤ L1 ≤ 1.5 mm. By controlling the dimension L1 between 0.5 mm and 1.5 mm, an effective etching effect is achieved while also facilitating reasonable control of the amount of etching liquid discharged.

[0015] In some embodiments, the dimension L1 further satisfies the condition: 0.8 mm ≤ L1 ≤ 1.2 mm.

[0016] In some embodiments, the axial dimension of the groove near the conveying channel is denoted as L2, where 2 mm ≤ L2 ≤ 5 mm. By controlling the dimension L2 between 2 mm and 5 mm, the etching efficiency and structural strength of the etching roller can be effectively balanced.

[0017] In some embodiments, the dimension L2 further satisfies the condition: 2.5 mm ≤ L2 ≤ 4 mm.

[0018] In some embodiments, the depth of the groove is denoted as h1, where 1 mm ≤ h1 ≤ 5 mm. With this design, the dimension h1 is controlled between 1 mm and 5 mm, which can effectively balance the etching efficiency and structural strength of the etching roller.

[0019] In some embodiments, the dimension h1 further satisfies the condition: 2 mm ≤ h1 ≤ 4 mm.

[0020] In some embodiments, the grooves include a plurality of grooves, at least some of which extend and intersect on the roller surface to enclose a plurality of grids. This design, through the intersecting grooves, forms a plurality of grids on the roller surface, facilitating the formation of convex structures on the metal layer during the etching process, thereby increasing the roughness of the metal layer.

[0021] In some embodiments, the area of ​​the grid is denoted as S2, where 1 mm 2 ≤S2≤50mm 2 By designing this way, the area S2 of the grid is controlled at 1mm 2 ~50mm 2 The size of the protrusions of the metal layer during corrosion is better, thereby making the roughness on the metal layer higher.

[0022] In some embodiments, the area S2 also satisfies the following conditions: 5mm 2 ≤S2≤30mm 2 .

[0023] In some embodiments, the etching portion comprises a raised portion disposed on the roller surface, with one end of the discharge hole extending to the surface of the raised portion. This design, wherein the etching portion is a raised portion, forms an indentation on the surface of the metal layer during the etching process, accelerating the etching of the metal layer and increasing the surface roughness.

[0024] In some embodiments, the height of the raised portion protruding from the roller surface is denoted as h2, where 1 mm ≤ h2 ≤ 5 mm. This design, which controls the height of the raised portion protruding from the roller surface to between 1 mm and 5 mm, effectively reduces the likelihood of etching liquid overflow. It also effectively reduces the likelihood of wrinkling the metal layer during embossing, thereby improving the etching effect.

[0025] In some embodiments, the dimension h2 further satisfies the condition: 2 mm ≤ h2 ≤ 4 mm.

[0026] In some embodiments, the etching portion comprises a recessed portion, which is provided on the roller surface and recessed toward the conveying channel, with one end of the discharge hole extending into the recessed portion. In this design, the etching portion is designed as a recessed portion, and the surface of the metal layer is etched by surface etching to obtain a higher roughness.

[0027] In some embodiments, the depth of the recessed portion is denoted as h3, where 1 mm ≤ h3 ≤ 5 mm. This design, which controls the depth of the recessed portion to between 1 mm and 5 mm, effectively reduces the likelihood of etching liquid overflow and also effectively reduces the likelihood of wrinkling the metal layer during embossing, thereby improving the etching effect.

[0028] In some embodiments, the dimension h3 further satisfies the condition: 2 mm ≤ h3 ≤ 4 mm.

[0029] Secondly, this application proposes an etching device comprising: a backing roller; and an etching roller such as any of the above, with a metal layer passing between the etching roller and the backing roller. This design, using the above etching roller, not only achieves targeted etching but also facilitates precise control of the liquid output, resulting in more uniform and reliable etching on the metal layer, improved corrosion results, and enhanced bonding strength on the metal layer, thereby improving battery reliability.

[0030] In some embodiments, the etching apparatus further includes a heater for heating the backing roller and / or the etching roller. This design and the inclusion of a heater can improve etching uniformity and insulate the etching solution, significantly improving the surface roughness of the metal layer.

[0031] In some embodiments, the etching device further includes a collection tank for recovering the etching liquid on the etching roller. This design, in which the collection tank is provided to collect the etching liquid flowing out during the etching process, is not only conducive to the recycling of the etching liquid, but also helps improve the working environment.

[0032] Thirdly, the present application proposes a method for processing a metal layer, utilizing any of the aforementioned etching equipment. The method comprises the following steps: introducing an etching liquid into a delivery channel and driving an etching roller to rotate about its axis; and cleaning and drying the metal layer that passes through the etching roller. This design utilizes the etching equipment to perform etching processing on the metal layer, facilitating precise control of the liquid output, resulting in more uniform and reliable etching of the metal layer, improving the etching effect, and enhancing the bonding strength of the metal layer, thereby improving battery reliability.

[0033] In some embodiments, the parameters of the etching solution include at least one of the following:

[0034] The temperature of the corrosive liquid is 25℃~80℃;

[0035] The concentration of the etching solution is 80g / L to 120g / L. With this design, the temperature of the etching solution is controlled between 25°C and 80°C; and / or the concentration of the etching solution is controlled between 80g / L and 120g / L, which facilitates accelerating the etching efficiency and improving the etching effect.

[0036] In some embodiments, the etching solution comprises at least one of sodium hydroxide, potassium hydroxide, phosphoric acid, acetic acid, nitric acid, and sulfuric acid; or, the etching solution comprises a compound containing trivalent iron ions. With this design, the etching solution composition is appropriately configured to achieve an effective etching effect.

[0037] In some embodiments, the steps of cleaning and drying the metal layer after it passes through the etching roller include: washing the metal layer with water and squeezing it; cleaning the squeezed metal layer with a polishing liquid; and sequentially washing, squeezing, and drying the cleaned metal layer. This design removes residual etching liquid through washing with polishing liquid and improves the brightness of the metal layer, resulting in a higher quality metal layer.

[0038] In some embodiments, the light emitting liquid includes nitric acid, wherein the concentration of the nitric acid is 300 mL / L to 500 mL / L. Thus, controlling the concentration of the nitric acid to 300 mL / L to 500 mL / L is beneficial for improving the light emitting effect of the metal layer.

[0039] In a fourth aspect, the present application provides a metal layer, wherein the metal layer is etched using any of the above-mentioned etching equipment; or the metal layer is processed using any of the above-mentioned metal layer processing methods, and the metal layer has a surface having an etched concave portion. Such an arrangement forms the etched concave portion on the metal layer, thereby increasing the roughness of the metal layer and thereby improving the bonding strength of the metal layer.

[0040] In some embodiments, the thickness of the metal layer is denoted as h4, and the depth of the etching concave is denoted as h5, where 0.1≤h5 / h4≤0.5. This design controls the ratio of the etching concave depth to the thickness of the metal layer to between 0.1 and 0.5, achieving the desired roughness-enhancing etching effect without increasing the sheet resistance of the metal layer or degrading the mechanical properties of the current collector due to excessive etching.

[0041] In some embodiments, the thickness h4 satisfies the condition: 0.7 μm ≤ h4 ≤ 2 μm. In this design, the thickness of the metal layer is controlled between 0.7 μm and 2 μm, which can meet the high energy density requirements of the secondary battery and the roughness design of the metal layer surface.

[0042] In some embodiments, the thickness h4 further satisfies the condition: 1 μm≤h4≤1.5 μm.

[0043] In some embodiments, the area of ​​the corrosion concave portion is recorded as S3, where 1 mm 2 ≤S3≤50mm 2 This design controls the area of ​​the corrosion concave part to 1mm. 2 ~50mm 2 , so that the metal layer has high roughness while also having good electrical conductivity and structural mechanical properties.

[0044] In some embodiments, the area S3 also satisfies the following conditions: 5mm 2 ≤S3≤30mm 2 .

[0045] In some embodiments, the roughness of the surface of the metal layer having the corrosion recess satisfies at least one of the following conditions:

[0046] 0.2μm≤Ra≤1μm;

[0047] 1μm≤Rz≤3μm, where Ra refers to the average surface roughness of the metal layer and Rz refers to the overall surface roughness of the metal layer. This design results in a higher roughness of the metal layer, improving the bonding strength of the metal layer, thereby improving the reliability of the secondary battery.

[0048] In a fifth aspect, the present application proposes a current collector, which includes any one of the metal layers described above.

[0049] In some embodiments, the current collector further comprises a substrate layer, the metal layer is disposed on at least one side of the substrate layer, and the corrosion recess is disposed on the side of the metal layer facing away from the substrate layer. This design, using the above metal layer, provides a higher surface roughness, which helps improve the bonding strength of the metal layer, thereby enhancing battery reliability.

[0050] In a sixth aspect, the present application proposes a pole piece, which includes the above current collector.

[0051] In a seventh aspect, the present application proposes an electrode assembly, which includes the above-mentioned electrode piece.

[0052] In an eighth aspect, the present application proposes a secondary battery, which includes the above electrode assembly.

[0053] In a ninth aspect, the present application proposes an electrical device, which includes the above-mentioned secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0055] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0057] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0058] FIG2 is a schematic diagram of the exploded structure of a secondary battery provided in some embodiments of the present application.

[0059] FIG3 is a schematic structural diagram of a grooved etching roller provided in some embodiments of the present application.

[0060] FIG4 is a cross-sectional view of the structure of the etching roller shown in FIG3.

[0061] FIG5 is a schematic structural diagram of an etching roller having raised or recessed portions provided in some embodiments of the present application.

[0062] FIG6 is a cross-sectional view of the structure of an etching roller with a protrusion provided in some embodiments of the present application.

[0063] FIG7 is a cross-sectional view of the structure of an etching roller with a recessed portion provided in some embodiments of the present application.

[0064] FIG8 is a schematic structural diagram of an etching roller having both raised portions or recessed portions and grooves according to some embodiments of the present application.

[0065] FIG9 is a schematic diagram of the structure of the corrosion equipment provided in some embodiments of the present application.

[0066] FIG10 is a first flow chart of a method for processing a metal layer according to some embodiments of the present application.

[0067] FIG11 is a second flow chart of a method for processing a metal layer provided in some embodiments of the present application.

[0068] FIG12 is a first structural diagram of the surface of a metal layer provided in some embodiments of the present application.

[0069] FIG13 is a second structural schematic diagram of the metal layer surface provided in some embodiments of the present application.

[0070] FIG14 is a cross-sectional view of the structure of the metal layer provided in some embodiments of the present application.

[0071] FIG15 is a cross-sectional view of the structure of a composite current collector provided in some embodiments of the present application.

[0072] 100. Etching roller; 10. Roller body; 11. Conveying channel; 12. Discharge hole; 13. Axis; 14. Roller surface; 20. Etching portion; 21. Grooving; 211. First groove wall; 212. Second groove wall; 22. Grid; 23. Raised portion; 24. Recessed portion; 200. Back roller; 300. Collecting tank; 400. Electrical device; 40. Controller; 41. Secondary battery; 42. Motor; 411. End cover; 412. Electrode terminal; 413. Electrode assembly; 414. Shell; 415. Metal layer; 416. Etching recess; 500. Current collector; 510. Substrate layer. DETAILED DESCRIPTION

[0073] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0074] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0075] As a key component in lithium-ion batteries, pole pieces typically consist of a current collector and an active layer, with the active layer typically placed on a metal layer. To facilitate bonding between the active and metal layers, the metal layer's surface is typically roughened. Roughening methods typically include physical and electrochemical methods. For example, roughening can involve using an indentation roller to create indentations that increase the surface roughness of the metal layer, or using electrochemical equipment to corrode the metal layer's surface.

[0076] However, all of the above roughening methods have problems such as low roughness and uneven roughness of the metal layer, which leads to insufficient bonding between the active layer and the metal layer, easily causing film peeling under high pressure density, or film peeling under long-term battery cycling, causing battery cell diving, affecting battery reliability.

[0077] Based on this, in order to address the problem of insufficient bonding force on the metal layer in the above-mentioned traditional roughening, the present application proposes a corrosion roller, in which a conveying channel is provided inside the roller body along the axial direction, and the corrosive liquid in the conveying channel is conveyed to the corrosion part through the discharge hole; and then discharged from the corrosion part to the outside of the corrosion roller. In this way, when corroding the metal layer, the corrosion part can output the corrosive liquid to the metal layer when it contacts the metal layer, so as to effectively corrode the surface of the metal layer. Since the corrosive liquid is output from the inside of the corrosion roller to the outside and finally output on the corrosion part, it not only achieves fixed-point corrosion, but also facilitates precise control of the liquid output, making the corrosion on the metal layer more uniform and reliable, improving the corrosion effect, and helping to enhance the bonding force on the metal layer, thereby improving the reliability of the battery.

[0078] In addition, when the corrosion work is not being performed, a cleaning agent can be introduced into the conveying channel to clean the corroded part, which can play a role in cleaning and preventing precipitation.

[0079] The corrosion roller proposed in this application is not only applicable to the bonding process between the metal layer and the active layer, but also to the bonding process between the metal layer and other substances, such as: the bonding between the metal layer and the substrate layer in the composite current collector.

[0080] The secondary batteries disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system comprising the battery cells and batteries disclosed in this application can be used to construct such electrical devices. This helps mitigate and automatically regulate the deterioration of cell expansion force, replenish electrolyte consumption, and improve battery performance stability and battery life.

[0081] The present invention provides an electrical device using a secondary battery as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0082] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device according to an embodiment of the present application.

[0083] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle provided in some embodiments of the present application. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery is provided inside the vehicle, and the battery can be provided at the bottom, head or tail of the vehicle. The battery can be used to power the vehicle, for example, the battery can be used as an operating power source for the vehicle. The vehicle may also include a controller 40 and a motor 42, and the controller 40 is used to control the battery to power the motor 42, for example, for starting, navigating and driving the vehicle.

[0084] In some embodiments of the present application, the secondary battery 41 can serve not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0085] In the battery system, there can be multiple secondary batteries 41, and the multiple secondary batteries 41 can be connected in series, in parallel, or in a mixed connection. Mixed connection means that the multiple secondary batteries 41 are both connected in series and in parallel. Multiple secondary batteries 41 can be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple secondary batteries 41 is accommodated in a box; of course, the battery can also be a battery module formed by first connecting multiple secondary batteries 41 in series, in parallel, or in a mixed connection, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in a box. The battery can also include other structures. For example, the battery can also include a busbar component for realizing electrical connection between multiple secondary batteries 41. Among them, the secondary battery 41 can be cylindrical, flat, rectangular, or other shapes.

[0086] Please refer to Figure 2, which is a schematic diagram of the exploded structure of a secondary battery 41 provided in some embodiments of the present application. Secondary battery 41 is the smallest unit of a battery. As shown in Figure 2, secondary battery 41 includes an end cap 411, a housing 414, an electrode assembly 413, and other functional components.

[0087] The end cap 411 refers to a component that covers the opening of the housing 414 to isolate the internal environment of the secondary battery 41 from the external environment. Without limitation, the shape of the end cap 411 can be adapted to the shape of the housing 414 to match the housing 414. The end cap 411 can be made of a material with a certain hardness and strength (such as an aluminum alloy). In this way, the end cap 411 is less likely to deform when squeezed or collided, so that the secondary battery 41 can have higher structural strength and improved safety performance. Functional components such as electrode terminals 412 can be provided on the end cap 411. The electrode terminal 412 can be used to electrically connect to the electrode assembly 413 for outputting or inputting electrical energy into the secondary battery 41. In some embodiments, the end cap 411 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the secondary battery 41 reaches a threshold. The material of the end cap 411 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this. In some embodiments, an insulating member may be provided inside the end cap 411 to isolate the electrical connection components in the housing 414 from the end cap 411 to reduce the risk of short circuit.

[0088] The shell 414 is a component used to cooperate with the end cap 411 to form the internal environment of the secondary battery 41, wherein the formed internal environment can be used to accommodate the electrode assembly 413, electrolyte and other components. The shell 414 and the end cap 411 can be independent components. An opening can be set on the shell 414, and the internal environment of the secondary battery 41 is formed by covering the opening with the end cap 411. Without limitation, the end cap 411 and the shell 414 can also be integrated. Specifically, the end cap 411 and the shell 414 can form a common connection surface before other components are put into the shell. When the interior of the shell 414 needs to be encapsulated, the end cap 411 is covered with the shell 414. The shell 414 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 414 can be determined according to the specific shape and size of the electrode assembly 413. The shell 414 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0089] The electrode assembly 413 is a component in the secondary battery 41 where electrochemical reactions occur. One or more electrode assemblies 413 may be contained in the housing 414. The electrode assembly 413 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly 413, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute a tab. The positive electrode tab and the negative electrode tab may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs are connected to the electrode terminals 412 to form a current loop.

[0090] According to some embodiments of the present application, referring to FIG. 3 and FIG. 4 , the present application provides an etching roller 100 comprising a roller body 10 and an etching portion 20. The roller body 10 is provided with a conveying channel 11 extending along its axis 13. The etching portion 20 is disposed on the roller body 10. The inner wall of the conveying channel 11 is provided with a discharge hole 12, which extends to the etching portion 20 and is provided on the etching portion 20 for communication with the exterior of the etching roller 100.

[0091] The roller body 10 is a cylindrical or nearly cylindrical structure. When corroding the surface of the metal layer 415, the roller body 10 rolls the surface of the metal layer 415 around its axis 13. The metal layer 415 is the component on the current collector 500 that carries the active material and outputs the current generated by the active material. In the positive electrode sheet, the metal layer 415 can be made of, but not limited to, aluminum or nickel. In the negative electrode sheet, the metal layer 415 can be made of, but not limited to, copper.

[0092] The delivery channel 11 is a flow channel structure inside the roller body 10, which allows a corrosive medium, such as a corrosive liquid, to be passed into the delivery channel 11. Meanwhile, a discharge hole 12 is provided on the inner wall of the delivery channel 11 and communicates with the delivery channel 11, so that the corrosive liquid in the delivery channel 11 can flow into the discharge hole 12.

[0093] Since the discharge hole 12 extends to the etching portion 20 and the portion on the etching portion 20 communicates with the outside, the etching liquid in the discharge hole 12 flows into the etching portion 20 and is output to the outside of the etching roller 100 through the etching portion 20 .

[0094] The shape of the discharge hole 12 can be designed in various ways, as long as it can discharge the corrosive liquid from the delivery channel 11. For example, the shape of the discharge hole 12 can be, but is not limited to, square, circular, elliptical, pentagonal, etc.

[0095] The corrosion portion 20 is a component on the roller body 10 that corrodes the metal layer 415. The corrosion portion 20 can have various designs, for example, a convex structure, a concave structure, or a groove structure. When the corrosion portion 20 is convex, one end of the discharge hole 12 can be extended to the outside of the corrosion portion 20 to allow the discharge hole 12 to communicate with the outside. When the corrosion portion 20 is concave or grooved, the discharge hole 12 can be extended to the outside of the corrosion portion 20 to allow the discharge hole 12 to communicate with the outside.

[0096] The number of the corrosion portion 20 and the number of the discharge holes 12 can be set to multiple. At the same time, the number of the corrosion portion 20 and the discharge holes 12 can be set one to one or one to many, that is, one end of the multiple discharge holes 12 extends to the corrosion portion 20.

[0097] Such a design not only achieves pinpoint corrosion, but also facilitates precise control of the liquid output, making the corrosion on the metal layer 415 more uniform and reliable, improving the corrosion effect, and helping to enhance the bonding force on the metal layer 415, thereby improving the reliability of the battery.

[0098] According to some embodiments of the present application, referring to FIG. 4 , the hole area of ​​the discharge hole 12 is recorded as S1, where 1 square millimeter (mm 2 )≤S1≤10mm 2 .

[0099] The area of ​​the discharge hole 12 can affect the amount of etching liquid outputted from the etching portion 20. If the hole area is too small, it will not only affect the amount of etching liquid output, but also easily cause blockage; if the hole area is too large, it will not only affect the structural strength of the etching roller 100, but also cause excessive liquid output, increasing the etching cost.

[0100] To this end, the hole area S1 is controlled at 1mm 2 ~10mm 2 For example, the hole area S1 can be but not limited to 1mm 2 , 2mm 2 , 3mm 2 , 4mm 2 , 5mm 2 , 6mm 2 , 7mm 2 , 8mm 2 , 9mm 2 , 10mm 2 wait.

[0101] Of course, in some other embodiments, the hole area S1 also meets the following conditions: 3mm 2 ≤S1≤7mm 2For example: the hole area S1 can be but not limited to 3mm 2 , 3.5mm 2 , 4mm 2 , 4.5mm 2 , 5mm 2 , 5.5mm 2 , 6mm 2 , 6.5mm 2 , 7mm 2 wait.

[0102] This design controls the hole area S1 to 1mm 2 ~10mm 2 Under the premise of achieving effective roughness, it can effectively balance the smoothness of liquid discharge and corrosion cost.

[0103] According to some embodiments of the present application, the roller body 10 has a roller surface 14 circumferentially arranged around its own axis 13, and at least part of the corrosion portion 20 is arranged on the roller surface 14; and / or, at least part of the corrosion portion 20 is arranged inside the roller body 10, and the end away from the conveying channel 11 is not lower than the roller surface 14.

[0104] The etched portion 20 may be disposed on the roller surface 14 or may be disposed inside the roller body 10 and extend outside the roller surface 14 or be flush with the roller surface 14. Of course, in some embodiments, a portion of the etched portion 20 is disposed on the roller surface 14, while another portion is disposed inside the roller body 10 and extends flush with the roller surface 14 or beyond the roller surface 14.

[0105] With such a design, the corrosion portion 20 is reasonably provided on the roller body 10 , so that the corrosion portion 20 can effectively corrode the metal layer 415 , increase the roughness of the metal layer 415 , and improve the bonding force on the metal layer 415 .

[0106] According to some embodiments of the present application, referring to FIG. 4 , the etching portion 20 includes a groove 21 . The groove 21 is disposed within the roller body 10 , with the end thereof away from the conveying channel 11 being no lower than the roller surface 14 . The discharge hole 12 communicates with the exterior of the etching roller 100 through the groove 21 .

[0107] The groove 21 is a structure with a certain space. When the etching liquid flows into the groove 21 from the discharge hole 12, the etching liquid can be discharged from the etching roller 100 through the end of the groove 21 away from the conveying channel 11. The end of the groove 21 away from the conveying channel 11 can be provided with one or more notches to allow the etching liquid to be discharged to the surface of the metal layer 415.

[0108] One end of the groove 21 may be flush with the roller surface 14 or extend beyond the roller surface 14. When one end of the groove 21 extends beyond the roller surface 14, the groove walls enclosing the groove 21 may protrude beyond the roller surface 14. In this case, when etching the metal layer 415, the groove 21 may form an indentation on the surface of the metal layer 415, thereby accelerating etching.

[0109] The groove 21 may have various shapes along its depth direction. For example, the groove 21 may have a trapezoidal, square, or elliptical shape along its depth direction.

[0110] In this design, the etching liquid is designed to have a structure of the grooves 21 , which facilitates effective etching of the surface of the metal layer 415 and improves the roughness of the metal layer 415 .

[0111] According to some embodiments of the present application, referring to FIG. 4 , the dimension of the end of the groove 21 away from the conveying channel 11 in the direction of the axis 13 is smaller than the dimension of the end of the groove 21 close to the conveying channel 11 in the direction of the axis 13 .

[0112] At both ends of the groove 21, the size of the end close to the delivery channel 11 is larger than the size of the end away from the delivery channel 11, which means that the space for the output of the corrosive liquid can be smaller than the space for the input of the corrosive liquid, which is convenient for the concentrated output of the corrosive liquid to achieve better targeted corrosion.

[0113] Specifically in some embodiments, please refer to Figure 4, the groove wall of the groove 21 includes a first groove wall 211 and a second groove wall 212 spaced apart along the axis 13, and the distance between the first groove wall 211 and the second groove wall 212 gradually decreases from the end of the groove 21 close to the conveying channel 11 to the end of the groove 21 away from the conveying channel 11.

[0114] This design makes it easier to concentrate the corrosive liquid and output it outward, achieving better targeted corrosion and improving the corrosion effect.

[0115] According to some embodiments of the present application, referring to FIG. 4 , a dimension of an end of the groove 21 away from the conveying channel 11 in the direction of the axis 13 is denoted as L1 , wherein 0.5 mm ≤ L1 ≤ 1.5 mm.

[0116] The selection of size L1 can affect the amount of liquid output from the groove 21. For example, if the size L1 is too small, the amount of etching liquid output will be reduced, affecting the etching effect. If the size L1 is too large, the amount of etching liquid output will be too large, resulting in excessive corrosion on the metal layer 415, which not only reduces the structural strength of the metal layer 415, but also increases the square resistance of the metal layer 415.

[0117] To this end, the dimension L1 may be between 0.5 mm and 1.5 mm, such as, but not limited to, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, etc. In other embodiments, the dimension L1 further satisfies the condition: 0.8 mm ≤ L1 ≤ 1.2 mm, such as, but not limited to, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, etc.

[0118] With this design, the dimension L1 is controlled between 0.5 mm and 1.5 mm, which facilitates reasonable control of the amount of the etching liquid while achieving an effective etching effect.

[0119] According to some embodiments of the present application, referring to FIG. 4 , a dimension of an end of the groove 21 close to the conveying channel 11 in the direction of the axis 13 is denoted as L2, wherein 2 mm ≤ L2 ≤ 5 mm.

[0120] The selection of dimension L2 can affect the amount of etching liquid entering the groove 21; it also affects the strength of the roller body 10 itself. For example, if dimension L2 is too small, the amount of etching liquid entering is reduced, reducing the etching efficiency; if dimension L2 is too large, the structural strength of the roller body 10 will be reduced.

[0121] To this end, the dimension L2 can be between 2 mm and 5 mm, such as, but not limited to, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm. In other embodiments, the dimension L2 also satisfies the condition: 2.5 mm ≤ L2 ≤ 4 mm. For example, the dimension L2 can be, but not limited to, 2.5 mm, 2.7 mm, 2.9 mm, 3 mm, 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm, and 4 mm.

[0122] With such a design, the dimension L2 is controlled between 2 mm and 5 mm, which can effectively balance the corrosion efficiency and structural strength of the corrosion roller 100 .

[0123] According to some embodiments of the present application, referring to FIG. 4 , the depth of the groove 21 is denoted as h1, where 1 mm ≤ h1 ≤ 5 mm.

[0124] Likewise, the depth of the groove 21 may also affect the amount of etching liquid discharged from the groove 21, thereby affecting the etching efficiency. Furthermore, if the depth of the groove 21 is too great, the structural strength of the roller body 10 may also be weakened.

[0125] To this end, the depth h1 of the groove 21 is controlled to be between 1 mm and 5 mm, such as, but not limited to, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc. In other embodiments, the dimension h1 further satisfies the condition of 2 mm ≤ h1 ≤ 4 mm, such as, but not limited to, 2 mm, 2.2 mm, 2.6 mm, 2.8 mm, 3 mm, 3.2 mm, 3.6 mm, 3.8 mm, 4 mm, etc.

[0126] With this design, the dimension h1 is controlled between 1 mm and 5 mm, which can effectively balance the corrosion efficiency and structural strength of the corrosion roller 100 .

[0127] According to some embodiments of the present application, referring to FIG. 3 , the grooves 21 include a plurality of grooves, and at least a portion of the grooves 21 extend and intersect on the roller surface 14 to enclose and form a plurality of grids 22 .

[0128] The extending direction of the grooves 21 on the roller surface 14 is not limited, as long as at least some of the grooves 21 intersect with each other to form a grid 22. The shape of the grid 22 can be designed in various ways, such as, but not limited to, triangles, squares, pentagons, hexagons, etc., and of course, irregular shapes are also possible.

[0129] When etching the metal layer 415, the grooves 21 form a concave etching structure on the surface of the metal layer 415. Meanwhile, a convex etching structure forms on the surface of the metal layer 415 corresponding to the grid 22. This gives the metal layer 415 a concave-convex structure, resulting in a higher roughness.

[0130] In addition, when one end of the groove 21 protrudes from the roller surface 14, the formed grid 22 presents a concave or groove-shaped structure, so that during the corrosion process, the part on the metal layer 415 is more likely to bulge at the grid 22, increasing the roughness of the metal layer 415.

[0131] With such a design, a plurality of grids 22 are formed on the roller surface 14 through the mutually intersecting grooves 21 , which facilitates the formation of a convex structure on the metal layer 415 during the corrosion process, thereby increasing the roughness of the metal layer 415 .

[0132] According to some embodiments of the present application, the area of ​​the grid 22 is recorded as S2, where 1mm 2 ≤S2≤50mm 2 .

[0133] The area S2 of the grid 22 can be 1mm 2 ~50mm 2 For example, the area S2 can be but not limited to 1mm 2 , 5mm 2, 10mm 2 , 20mm 2 , 30mm 2 , 40mm 2 , 50mm 2 wait.

[0134] In some other embodiments, the area S2 also satisfies the following conditions: 5mm 2 ≤S2≤30mm 2 For example, the area S2 can be but not limited to 5mm 2 , 10mm 2 , 15mm 2 , 20mm 2 , 25mm 2 , 30mm 2 wait.

[0135] By designing in this way, the area S2 of the grid 22 is controlled at 1 mm 2 ~50mm 2 The metal layer 415 has a better protrusion size during corrosion, thereby making the roughness on the metal layer 415 higher.

[0136] According to some embodiments of the present application, referring to FIG. 5 and FIG. 6 , the corrosion portion 20 includes a protrusion 23 . The protrusion 23 is disposed on the roller surface 14 , and one end of the discharge hole 12 extends to the surface of the protrusion 23 .

[0137] The raised portion 23 refers to a structure protruding from the roller surface 14. During the etching process, the raised portion 23 can form an indentation on the metal layer 415. At the same time, the etching liquid is output from the surface of the raised portion 23 into the indentation, making the concave structure more prominent.

[0138] The raised portions 23 can be attached to the roller surface 14 using a combination of methods, such as bonding, welding, or threaded connections. Alternatively, they can be connected using an integrated molding method, such as injection molding, extrusion, or 3D printing. Furthermore, the number of raised portions 23 can be multiple, and all raised portions 23 can be arranged on the roller surface 14 in a regular pattern, such as a matrix or annular spacing, or in a random pattern.

[0139] Furthermore, the protrusions 23 and the grooves 21 can be provided simultaneously on the etching roller 100. This allows the metal layer 415 to be formed with both the etching marks formed by the protrusions 23 and the etching marks formed by the grooves 21, further enhancing the roughness of the metal layer 415. The protrusions 23 and the grooves 21 can be distributed in various ways on the etching roller 100, such as providing the protrusions 23 in one area and the grooves 21 in another area. Alternatively, the protrusions 23 and the grooves 21 can be interwoven, as shown in FIG8 , where the protrusions 23 are provided in a grid 22 formed between the grooves 21. When the protrusions 23 and the grooves 21 are provided simultaneously on the etching roller 100, the height of the protrusions 23 above the roller surface 14 can be set to be consistent with, or approximately consistent with, the height of the grooves 21 above the roller surface 14.

[0140] In this design, the corrosion portion 20 is designed as a protrusion 23, so that an indentation is formed on the surface of the metal layer 415 during the corrosion process, which accelerates the corrosion of the metal layer 415 and improves the surface roughness.

[0141] According to some embodiments of the present application, referring to FIG. 6 , the height of the protruding portion 23 protruding from the roller surface 14 is denoted as h2, where 1 mm ≤ h2 ≤ 5 mm.

[0142] The height of the raised portion 23 above the roller surface 14 affects the etching effect on the metal layer 415. If the height is too low, the etching liquid may easily overflow onto the roller surface 14, causing a tail during etching and corroding the non-corroded metal surface. If the height is too high, the metal layer 415 may wrinkle during embossing.

[0143] To this end, the height of the protruding portion 23 protruding from the roller surface 14 is controlled to be between 1 mm and 5 mm. For example, the height h2 can be, but is not limited to, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, etc. In other embodiments, the dimension h2 also satisfies the condition: 2 mm ≤ h2 ≤ 4 mm. For example, the height h2 can be, but is not limited to, 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, 3 mm, 3.4 mm, 3.8 mm, 4 mm, etc.

[0144] With this design, the height of the protrusion 23 protruding from the roller surface 14 is controlled between 1 mm and 5 mm, which can effectively reduce the probability of corrosion liquid overflowing; at the same time, it also effectively reduces the probability of wrinkling of the metal layer 415 during stamping, thereby improving the corrosion effect.

[0145] According to some embodiments of the present application, referring to FIG. 7 , the corrosion portion 20 includes a recessed portion 24 . The recessed portion 24 is provided on the roller surface 14 and recessed toward one side of the conveying channel 11 . One end of the discharge hole 12 extends into the recessed portion 24 .

[0146] The recessed portion 24 is formed by the roller surface 14 concavely facing the conveying channel 11. The recessed portion 24 is lower than the roller surface 14, allowing the etching liquid in the discharge hole 12 to flow into the recessed portion 24. When the metal layer 415 is corroded, the recessed portion 24 contacts the surface of the metal layer 415, and the etching liquid in the recessed portion 24 adheres to the surface of the metal layer 415 and corrodes it, forming a corroded concave structure. This means that the etching of the metal layer 415 by the recessed portion 24 is surface corrosion. Of course, the etching of the metal layer 415 by the raised portion 23 is also surface corrosion.

[0147] To ensure uniform corrosion of the metal layer 415, a plurality of recesses 24 may be provided, with all recesses 24 spaced apart on the roller surface 14. The specific distribution of the recesses 24 can be designed in a variety of ways, such as in a matrix or in a circular pattern. The shape and size of the recesses 24 can be determined based on actual needs.

[0148] Furthermore, the recesses 24 and the grooves 21 can be simultaneously provided on the etching roller 100. This allows the metal layer 415 to be etched with both the recesses 24 and the grooves 21, further enhancing the roughness of the metal layer 415. Furthermore, the recesses 24 and the grooves 21 can be distributed in various ways on the etching roller 100, such as providing recesses 24 in one area and grooves 21 in another; or, alternatively, the recesses 24 and grooves 21 can be interwoven, as shown in FIG8 , where the recesses 24 are arranged in a grid 22 formed between the grooves 21. Furthermore, since the recesses 24 are provided below the roller surface 14, to ensure a more consistent etching depth across the metal layer 415, the end of the grooves 21 facing away from the conveying channel 11 can be flush or nearly flush with the roller surface 14.

[0149] In this design, the corrosion portion 20 is designed as a recessed portion 24, and the surface of the metal layer 415 is corroded by surface corrosion to obtain a higher roughness.

[0150] According to some embodiments of the present application, referring to FIG. 7 , the depth of the recessed portion 24 is denoted as h3, where 1 mm ≤ h3 ≤ 5 mm.

[0151] The depth of the recessed portion 24 can affect the etching effect on the metal layer 415. If the depth is too shallow, the etching liquid can easily overflow onto the roller surface 14, causing a tail during etching and corroding the non-corroded metal surface. If the depth is too deep, the protrusions around the recessed portion 24 are relatively high, which can easily cause wrinkles in the metal layer 415 during embossing.

[0152] The depth of the recessed portion 24 can be controlled to be between 1 mm and 5 mm. For example, the depth h3 can be, but is not limited to, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, or 5 mm. In other embodiments, the dimension h3 further satisfies the condition: 2 mm ≤ h3 ≤ 4 mm. For example, the depth h3 can be, but is not limited to, 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, 3 mm, 3.4 mm, 3.8 mm, or 4 mm.

[0153] With this design, the depth of the recessed portion 24 is controlled between 1 mm and 5 mm, which can effectively reduce the probability of the etching liquid overflowing. At the same time, it also effectively reduces the probability of the metal layer 415 being wrinkled during stamping, thereby improving the etching effect.

[0154] According to some embodiments of the present application, referring to FIG9 , the present application proposes an etching device, comprising: a backing roller 200 and an etching roller 100 as described above. A metal layer 415 is passed between the etching roller 100 and the backing roller 200.

[0155] The back roller 200 is opposite to the etching roller 100 and forms a gap for the metal layer 415 to pass through. When the metal layer 415 passes between the back roller 200 and the etching roller 100, the etching roller 100 and the back roller 200 will exert a certain squeezing force on the metal layer 415, so that the etching roller 100 can better corrode the surface of the metal layer 415.

[0156] When both surfaces of the metal layer 415 need to be corroded, the back roller 200 can also be designed as the structure of the corrosion roller 100, that is, the back roller 200 can also be provided with a corrosion portion 20, so that both surfaces of the metal layer 415 can be corroded simultaneously.

[0157] Such a design, using the above-mentioned etching roller 100, not only realizes fixed-point etching, but also facilitates precise control of the liquid output, making the etching on the metal layer 415 more uniform and reliable, improving the etching effect, and being conducive to enhancing the bonding force on the metal layer 415, thereby improving the reliability of the battery.

[0158] According to some embodiments of the present application, the etching device further includes a heater, which is used to heat the backing roller 200 and / or the etching roller 100 .

[0159] A heater is a device capable of heating the backing roller 200 and / or the etching roller 100. For example, it may be, but is not limited to, an electric heater or a device providing a heat transfer medium. The heat transfer medium device can provide a high-temperature heat transfer medium, such as thermal oil or hot water, to the backing roller 200 and / or the etching roller 100. In this case, the backing roller 200 may be designed as a hollow roller.

[0160] When the heater can pass the heat-conducting medium into the back roller 200 or the corrosion roller 100, the heat-conducting medium has a certain pressure in the back roller 200 or the corrosion roller 100, and the pressure value can be determined according to the actual product, for example: the pressure can be greater than or equal to 10N and less than or equal to 20N, etc.

[0161] Such a design and the introduction of a heater can increase the corrosion uniformity and keep the corrosion liquid warm, thereby greatly improving the surface roughness of the metal layer 415 .

[0162] According to some embodiments of the present application, referring to FIG. 9 , the etching device further includes a collecting tank 300 , which is used to recover the etching liquid on the etching roller 100 .

[0163] The collecting tank 300 refers to a device capable of collecting the etching liquid flowing out of the etching roller 100 , and can be disposed directly below the etching roller 100 .

[0164] With such a design, the collection tank 300 is provided to collect the etching liquid flowing out during the etching process, which is not only beneficial to the recycling of the etching liquid, but also beneficial to improving the working environment.

[0165] According to some embodiments of the present application, referring to FIG. 10 , the present application proposes a method for processing a metal layer, using any of the above etching equipment, the method for processing the metal layer comprising the following steps:

[0166] S100, introducing etching liquid into the conveying channel 11, and driving the etching roller 100 to rotate around its own axis 13;

[0167] S200 , cleaning and drying the metal layer 415 that has passed through the etching roller 100 .

[0168] In step S100, after the etching liquid is fed into the delivery channel 11, it can flow into the etching portion 20 through the discharge hole 12 and then flow from the etching portion 20 to the metal surface, thereby etching the surface. When the etching portion 20 is a groove 21, the groove 21 not only forms an indentation on the surface of the metal layer 415, but also delivers the etching liquid to the surface of the metal layer 415 through one end of the groove 21. When the etching portion 20 is a protrusion 23, the protrusion 23 presses against the surface of the metal layer 415, and the etching liquid is delivered to the metal layer 415 through the surface of the protrusion 23. When the etching portion 20 is a depression 24, the depression 24 abuts the surface of the metal layer 415, and the etching liquid in the depression 24 adheres to the metal layer 415.

[0169] In step S200, the metal layer 415 is cleaned to remove the residual corrosive liquid on the metal layer 415. The metal layer 415 is dried to keep the surface of the metal layer 415 dry for subsequent operations.

[0170] With this design, the metal layer 415 is corroded using corrosion equipment, which facilitates precise control of the liquid output, making the corrosion on the metal layer 415 more uniform and reliable, improving the corrosion effect, and helping to enhance the bonding strength on the metal layer 415, thereby improving the reliability of the battery.

[0171] According to some embodiments of the present application, the parameters of the etching solution include at least one of the following:

[0172] The temperature of the corrosive liquid is 25 degrees Celsius (℃) to 80℃;

[0173] The concentration of the corrosive solution is 80g / L to 120g / L.

[0174] The temperature of the etching liquid may be between 25°C and 80°C. For example, the temperature of the etching liquid may be, but is not limited to, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 70°C, 80°C, etc.

[0175] The concentration of the etching solution can be between 80 g / L and 120 g / L. For example, the concentration of the etching solution can be but not limited to 80 grams per liter (g / L), 85 g / L, 90 g / L, 95 g / L, 100 g / L, 105 g / L, 110 g / L, 115 g / L, 120 g / L, etc.

[0176] In addition, after the metal layer 415 passes through the etching roller 100 , the etching time can be adjusted according to actual needs. For example, the etching time can be, but is not limited to, 1S to 30S.

[0177] With this design, the temperature of the etching solution is controlled between 25° C. and 80° C.; and / or the concentration of the etching solution is controlled between 80 g / L and 120 g / L, so as to accelerate the etching efficiency and improve the etching effect.

[0178] According to some embodiments of the present application, the components of the etching liquid include at least one of sodium hydroxide, potassium hydroxide, phosphoric acid, acetic acid, nitric acid, and sulfuric acid; or, the components of the etching liquid include a compound containing trivalent iron ions.

[0179] When the metal layer 415 is in the positive electrode, the components of the etching solution may include one or more of sodium hydroxide, potassium hydroxide, phosphoric acid, acetic acid, nitric acid, sulfuric acid, etc. When the metal layer 415 is in the negative electrode, the components of the etching solution may include trivalent iron ion compounds, such as FeCl3, FeNO3, etc.

[0180] With this design, the composition of the etching liquid is reasonably set to achieve an effective etching effect.

[0181] According to some embodiments of the present application, referring to FIG. 11 , S200 , the step of cleaning and drying the metal layer 415 that has passed through the etching roller 100 , includes:

[0182] S210, washing and extruding the metal layer 415;

[0183] S220, cleaning the extruded metal layer 415 with a polishing liquid;

[0184] S230 , the cleaned metal layer 415 is sequentially washed, squeezed and dried.

[0185] In step S210, the metal layer 415 may be washed by various methods, such as immersion, spraying, and flushing, wherein the washing method can remove the residual corrosive liquid on the metal layer 415. Furthermore, the metal layer 415 may be squeezed by various methods, such as squeezing with a squeezing roller.

[0186] In step S220 , the brightening liquid refers to a solvent capable of brightening the metal layer 415 .

[0187] With this design, the residual corrosive liquid can be removed by washing with water and cleaning with a light emitting liquid, and the brightness of the metal layer 415 can be improved, so that the quality of the obtained metal layer 415 is higher.

[0188] According to some embodiments of the present application, the composition of the light-emitting liquid includes nitric acid, wherein the concentration of the nitric acid is 300 milliliters per liter (mL / L) to 500 mL / L.

[0189] The concentration of nitric acid can be between 300 mL / L and 500 mL / L, for example, the concentration of nitric acid can be but not limited to 300 mL / L, 350 mL / L, 400 mL / L, 450 mL / L, 500 mL / L, etc. The nitric acid can be but not limited to 68% nitric acid.

[0190] With this design, the concentration of nitric acid is controlled within a range of 300 mL / L to 500 mL / L, which is beneficial for improving the light extraction effect of the metal layer 415 .

[0191] According to some embodiments of the present application, referring to FIG. 12 and FIG. 13 , a metal layer 415 is provided. The metal layer 415 is etched using any of the aforementioned etching equipment; or the metal layer 415 is processed using any of the aforementioned metal layer processing methods. The surface of the metal layer 415 has an etched recess 416.

[0192] The etching recess 416 is formed when the etching portion 20 delivers etching liquid to the surface of the metal layer 415 during the etching process. The etching recess 416 may have various shapes, such as, but not limited to, a mesh, a diamond, or a circle. Of course, the etching recess 416 may have a single pattern or a combination of multiple patterns.

[0193] The area of ​​the corrosion recess 416 can be determined according to actual needs. For example, the area of ​​the corrosion recess 416 can be 1 mm. 2 ~50mm 2 .

[0194] In this manner, the corrosion recess 416 is formed on the metal layer 415 , which can increase the roughness of the metal layer 415 , thereby improving the bonding strength of the metal layer 415 .

[0195] According to some embodiments of the present application, referring to FIG. 14 , the thickness of the metal layer 415 is denoted as h4, and the depth of the corrosion recess 416 is denoted as h5, wherein 0.1≤h5 / h4≤0.5.

[0196] The depth of the etching recess 416 can affect the roughness of the metal layer 415, but the depth should not be too deep. If it is too deep, the sheet resistance at a local location on the metal layer 415 will be too large, thereby affecting the conductive performance of the current collector 500. For example, the etching recess 416 does not penetrate the metal layer 415.

[0197] To this end, the ratio of the depth of the etching recess 416 to the thickness of the metal layer 415 is controlled to be between 0.1 and 0.5, for example, but not limited to, 0.1, 0.2, 0.3, 0.4, 0.5, etc.

[0198] With this design, the ratio of the depth of the corrosion recess 416 to the thickness of the metal layer 415 is controlled between 0.1 and 0.5, which can not only meet the corrosion effect of improving the roughness, but also avoid increasing the square resistance of the metal layer 415 and reducing the mechanical properties of the current collector 500 due to excessive corrosion.

[0199] According to some embodiments of the present application, the thickness h4 satisfies the condition: 0.7 μm≤h4≤2 μm.

[0200] When designing the thickness of the metal layer 415 , if it is too large, the energy density of the secondary battery 41 will be affected; if it is too small, it will not only affect the overall structural strength of the current collector 500 but also increase the difficulty of roughening the surface of the metal layer 415 .

[0201] To this end, the thickness of the metal layer 415 is controlled to be between 0.7 μm and 2 μm. For example, the thickness of the metal layer 415 may be, but is not limited to, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, etc. Of course, in some other embodiments, the thickness h4 also satisfies the condition of 1 μm ≤ h4 ≤ 1.5 μm, such as 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, etc.

[0202] With this design, the thickness of the metal layer 415 is controlled between 0.7 μm and 2 μm, which can meet the high energy density requirement of the secondary battery 41 and the roughened surface design of the metal layer 415 .

[0203] According to some embodiments of the present application, the area of ​​the corrosion recess 416 is recorded as S3, where 1 mm 2 ≤S3≤50mm 2 .

[0204] If the area of ​​the corrosion recess 416 is too small, the corrosion effect is not obvious and the roughness is low; if it is too large, the metal layer 415 will be corroded too much, resulting in increased square resistance and reduced conductivity; at the same time, the structural mechanical properties of the metal layer 415 will also be weakened.

[0205] To this end, the area of ​​the corrosion recess 416 can be 1mm 2 ~50mm 2 For example, the area S3 can be but not limited to 1mm 2 , 5mm 2 , 10mm 2 , 20mm 2 , 30mm 2 , 40mm 2 , 50mm 2 In some other embodiments, the area S3 also satisfies the following conditions: 5mm 2 ≤S3≤30mm 2 For example, the area S3 can be but not limited to 5mm 2 , 10mm 2 , 15mm 2 , 20mm 2 , 25mm 2 , 30mm 2 wait.

[0206] It should also be noted that in order to control the area of ​​the corrosion recess 416 to 1mm 2 ~50mm 2 In the meantime, the etched portion 20 on the etched roller 100 can be designed as a raised portion 23 or a recessed portion 24 .

[0207] This design controls the area of ​​the corrosion recess 416 to 1 mm 2 ~50mm 2 , so that the metal layer 415 has high roughness while also having good electrical conductivity and structural mechanical properties.

[0208] According to some embodiments of the present application, the roughness of the surface of the metal layer 415 having the corrosion recess 416 satisfies at least one of the following conditions:

[0209] 0.2μm≤Ra≤1μm;

[0210] 1 μm≤Rz≤3 μm, where Ra refers to the average surface roughness of the metal layer 415 , and Rz refers to the overall surface roughness of the metal layer 415 .

[0211] Roughness Ra and Rz are two parameters used to characterize surface roughness. Ra refers to the average surface roughness of the metal layer 415, that is, the arithmetic mean of the absolute values ​​of the profile deviations within the sampling length. Rz refers to the overall surface roughness of the metal layer 415, that is, the average value of the surface fluctuations within adjacent sampling lengths.

[0212] The roughness Ra may be, but is not limited to, 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1 μm, etc. The roughness Rz may be, but is not limited to, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, 2.5 μm, 3 μm, etc.

[0213] Such a design enables the metal layer 415 to have a higher roughness, thereby improving the bonding force of the metal layer 415 , thereby facilitating improved reliability of the secondary battery 41 .

[0214] According to some embodiments of the present application, the present application proposes a current collector 500 , which includes any one of the above metal layers 415 .

[0215] The current collector 500 may be a common current collector 500 , namely, only including the metal layer 415 ; or a composite current collector 500 , which may include the metal layer 415 and the substrate layer 510 .

[0216] With such a design, the metal layer 415 has a higher surface roughness, which is beneficial to improving the bonding force on the metal layer 415, thereby improving the reliability of the battery.

[0217] According to some embodiments of the present application, referring to FIG. 15 , the current collector 500 further includes a substrate layer 510 , a metal layer 415 is disposed on at least one side of the substrate layer 510 , and a corrosion recess 416 is disposed on the side of the metal layer 415 facing away from the substrate layer 510 .

[0218] The substrate layer 510 is a supporting structure within the composite current collector 500. The material of the substrate layer 510 may be selected from at least one of an organic polymer insulating material, an inorganic insulating material, and a composite material. Organic polymer insulating materials include at least one of polyamide, polyterephthalate, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, polybutylene terephthalate, poly(p-phenylene terephthalamide), polypropylene, polyoxymethylene, epoxy resin, phenolic resin, polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, and polycarbonate. Inorganic insulating materials include at least one of aluminum oxide, silicon carbide, and silicon dioxide. Composite materials include at least one of epoxy resin glass fiber reinforced composite materials and polyester resin glass fiber reinforced composite materials.

[0219] Meanwhile, the bonding between the substrate layer 510 and the metal layer 415 may be, but is not limited to, evaporation, water electroplating, chemical plating, adhesive bonding, and the like.

[0220] With such a design and the use of the above metal layer 415 , the current collector 500 and the active layer are more tightly bonded, which is beneficial to improving the reliability of the secondary battery 41 .

[0221] According to some embodiments of the present application, the present application proposes a pole piece, which includes the above current collector 500.

[0222] According to some embodiments of the present application, the present application proposes an electrode assembly 413, which includes the above electrode pieces.

[0223] According to some embodiments of the present application, the present application provides a secondary battery 41 , which includes the above electrode assembly 413 .

[0224] According to some embodiments of the present application, the present application provides an electric device 400 , which includes the above-mentioned secondary battery 41 .

[0225] According to some embodiments of the present application, referring to Figures 1 to 15 , an etching roller 100 and a metal layer 415 are provided. The etching roller 100 has a conveying channel 11 within it, with an exhaust hole 12 formed on the inner wall of the conveying channel 11. Furthermore, the etching roller 100 has an etching portion 20, and the exhaust hole 12 extends into the etching portion 20 for communication with the exterior of the etching roller 100. The etching portion 20 can include one of a groove 21, a protrusion 23, and a depression 24. Furthermore, the ratio of the depth of the etching recesses 416 formed on the surface of the metal layer 415 by etching to the thickness of the metal layer 415 is controlled to be between 0.1 and 0.5.

[0226] In order to make the purpose, technical solutions and advantages of this application more concise and clear, this application is illustrated with the following specific examples, but this application is by no means limited to these examples. The embodiments described below are only preferred embodiments of this application and can be used to describe this application. They should not be understood as limiting the scope of this application. It should be pointed out that any modifications, equivalent replacements and improvements made within the spirit and principles of this application should be included in the scope of protection of this application.

[0227] In order to better illustrate the present application, the present application is further described below in conjunction with the embodiments. The following are specific embodiments.

[0228] Example 1

[0229] Surface corrosion of metal layer 415

[0230] Metal layer 415 is made of aluminum with a thickness of 1 μm. The etching solution consists of sodium hydroxide at a concentration of 100 g / L, and the polishing solution is 68% nitric acid at a concentration of 400 mL / L. Furthermore, etching roller 100 is provided with a groove 21, which is trapezoidal in depth. Its dimension L1, along axis 13, is 1 mm at the end away from conveying channel 11, and its dimension L2, along axis 13, at the end away from conveying channel 11, is 3 mm. Its depth h1 is 3 mm. The height of one end of groove 21 protruding from roller surface 14 is 3 mm, and the area S1 of discharge hole 12 is 5 mm. 2 The area of ​​the grid 22 formed by the groove 21 is 10mm 2 .

[0231] In addition, the depth h5 of the etching recess 416 on the metal layer 415 is 0.1 μm, and the ratio of the depth of the etching recess 416 to the thickness of the metal layer 415 is 0.1.

[0232] The specific corrosion steps are as follows:

[0233] (1) First, add 100g of sodium hydroxide and 1L of deionized water in a mixing tank to prepare a sodium hydroxide concentration of 100g / L. The mixing tank has a heating function and heats the solution temperature to 35°C. The higher the temperature, the faster the corrosion rate. For every 10°C increase in temperature, the corrosion rate increases by 1 times.

[0234] (2) The prepared etching liquid is pumped into the delivery channel 11 of the etching roller 100 by means of a pump. The flow rate is adjusted so that the liquid outlet of the etching roller 100 can just soak the groove 21. At the same time, heat transfer oil is introduced into the backing roller 200 at a temperature of 35°C and a pressure of 15N to keep the etching liquid from the groove 21 of the etching roller 100 warm.

[0235] (3) The composite current collector 500 is placed at the unwinding position, and the tape is put on. The sample at the front of the machine before formal printing is used as the machine material. The sample is passed through the roller with a grid 22 and a groove 21, and then the etching roller 100 is embossed. The reaction time is 3S. After passing through a section of rollers, it is sprayed with water to wash away the residual sodium hydroxide. After passing through the squeezing roller, it is then cleaned with 68% nitric acid. After cleaning, it is sprayed with water again, and then passed through the squeezing roller to squeeze out the residual water. Finally, it is dried in an 80°C oven and rolled up to obtain a composite aluminum current collector 500 with a surface grid 22 and an etching groove 21.

[0236] (4) When the concentration of the etching solution is constant, the depth of the etching groove 21 is controlled by time and reaction temperature.

[0237] Preparation of composite current collector 500

[0238] The material of the substrate layer 510 is PET with a thickness of 8 μm. The metal layer 415 and the substrate layer 510 are combined by adhesive coating and lamination.

[0239] Preparation of electrode

[0240] Through the conventional battery coating process, the positive electrode active material LiNi0.8Co0.1Mn0.1O2, conductive carbon black SP and binder PVDF are dispersed in the solvent NMP in a weight ratio of 98:1:1 and mixed evenly to obtain a positive electrode slurry. The positive electrode slurry is coated on the surface of the above-mentioned composite current collector 500 and dried at 100°C to obtain a positive electrode plate. Based on the battery design requirements, current collector 500 areas of different widths are retained on both sides of the plate for welding metal tabs; the surface active material layer of the plate is compacted by the conventional battery cold pressing process, where the positive electrode plate compaction is set to 3.4g / cm 3 The negative electrode sheet density is set to 1.6g / cm 3 .

[0241] Example 2

[0242] The method is basically the same as that of Example 1, with the only difference being that the etching reaction time is 6 seconds and the depth h5 of the etching recess 416 is 0.2 μm.

[0243] Example 3

[0244] The method is basically the same as Example 1, with the only difference being that the etching reaction time is 10 seconds and the depth h5 of the etching recess 416 is 0.3 μm.

[0245] Example 4

[0246] The method is basically the same as that of Example 1, with the only difference being that the etching reaction time is 15 seconds and the depth h5 of the etching recess 416 is 0.4 μm.

[0247] Example 5

[0248] The method is basically the same as Example 1, with the only difference being that the etching reaction time is 25 seconds and the depth h5 of the etching recess 416 is 0.5 μm.

[0249] Comparative Example 1

[0250] The embodiment is basically the same as the embodiment 1, with the only difference being that the etching reaction time is 1 second, and the depth h5 of the etching recess 416 is 0.09 μm.

[0251] Comparative Example 2

[0252] The method is basically the same as that of Example 1, except that the etching reaction time is 33 seconds, and the depth h5 of the etching recess 416 is 0.6 μm.

[0253] Comparative Example 3

[0254] The embodiment is basically the same as the embodiment 1, with the only difference being that the metal layer 415 is not etched by the etching roller 100 .

[0255] Example 6

[0256] The method is basically the same as Example 1, except that the corrosion reaction time is 10 seconds, the depth h5 of the corrosion recess 416 is 0.3 μm, and the area of ​​the grid 22 is 1 mm. 2 .

[0257] Example 7

[0258] It is basically the same as Example 6, except that the area of ​​the grid 22 is 5mm 2 .

[0259] Example 8

[0260] It is basically the same as Example 6, except that the area of ​​the grid 22 is 20 mm 2 .

[0261] Example 9

[0262] It is basically the same as Example 6, except that the area of ​​the grid 22 is 30 mm 2 .

[0263] Example 10

[0264] It is basically the same as Example 6, except that the area of ​​the grid 22 is 50mm 2 .

[0265] Comparative Example 4

[0266] It is basically the same as Example 6, except that the area of ​​the grid 22 is 0.9 mm 2 .

[0267] Comparative Example 5

[0268] It is basically the same as Example 6, except that the area of ​​the grid 22 is 55mm 2 .

[0269] Example 11

[0270] The embodiment 3 is basically the same, except that the etching roller 100 has a protrusion 23, which protrudes 3 mm from the roller surface 14. After the metal layer 415 is etched, the etching area of ​​the etching concave portion 416 is 1.0 mm. 2 , wherein the corrosion area of ​​the corrosion recess 416 is the area formed by the corrosion of a single protrusion 23 on the metal layer 415 .

[0271] Example 12

[0272] The same as Example 11, except that the corrosion area of ​​the corrosion recess 416 is 5.0 mm 2 .

[0273] Example 13

[0274] The same as Example 11, except that the corrosion area of ​​the corrosion recess 416 is 10.0 mm 2 .

[0275] Example 14

[0276] The same as Example 11, except that the corrosion area of ​​the corrosion recess 416 is 30.0 mm 2 .

[0277] Example 15

[0278] The same as Example 11, except that the corrosion area of ​​the corrosion recess 416 is 50 mm 2 .

[0279] Comparative Example 6

[0280] The same as Example 11, except that the corrosion area of ​​the corrosion recess 416 is 0.8 mm 2 .

[0281] Comparative Example 7

[0282] The same as Example 11, except that the corrosion area of ​​the corrosion recess 416 is 55 mm 2 .

[0283] In each embodiment and comparative example, the metal layer 415 was tested for square resistance, roughness, and surface dyne value; the composite current collector 500 was tested for strength and ductility; and the electrode was tested for bonding strength. The specific test methods are as follows; at the same time, the test results and related parameters can be referred to Tables 1 and 2.

[0284] The square resistance test method of the metal layer 415 surface is as follows: a four-probe square resistance tester is used to test the square resistance of the large surface of the sample metal layer 415. 30 points are randomly tested, with the probes spanning the corroded area and the uncorroded area, and the average square resistance of the 30 points is taken.

[0285] Surface roughness test method of metal layer 415: Use a roughness tester to test and take Ra value and Rz value.

[0286] Ra average value = sum of Ra values ​​of 10 test points / 10 units (μm)

[0287] Rz mean value = sum of Rz values ​​of 10 test points / 10 units (μm)

[0288] Test method for the dyne value of the metal layer 415 surface: Use a 38# or larger dyne pen to draw horizontal and vertical lines on the surface of the metal layer 415. Check within 2 seconds whether there are any breakpoints on the lines. If not, it is considered qualified.

[0289] Composite current collector 500 strength and elongation test method: Use a standard sampler to cut the sample into 10 samples of 15 mm width and 15 cm length along the MD / TD direction; fix the sample on the clamp of the tensile testing machine, set the speed to 50 mm / min, and the gauge length between the clamps to 50 mm, and perform a tensile test to obtain the corresponding maximum strength and elongation in the breaking state.

[0290] Strength = sum of the maximum tensile strength of 10 samples / 10 units (MPa);

[0291] Elongation = the sum of the maximum tensile strengths of 10 samples / 10 units (%).

[0292] Electrode adhesion test method: Attach 3M double-sided tape to a steel plate with a width of 20mm and a length of 50mm. Cut the electrode into pieces with a width of 20mm and a length of 150mm and attach them to the tape. Use a high-speed rail tensile testing machine to measure the bonding strength between the active material layer and the metal layer 415 at a tensile speed of 5mm / min.

[0293] The average value of the electrode bonding force = the sum of the bonding force values ​​of 10 samples / 10 units (N / m).

[0294] Table 1

[0295] Table 2

[0296] As can be seen from Examples 1 to 5 and Comparative Examples 1 to 3, when the type of corrosion portion 20 is a groove 21, when the depth of the groove 21 is less than 0.1 μm and the ratio A to the metal layer 415 is also less than 0.1, the corrosion of the groove 21 does not help much in improving the roughness. When the depth of the groove 21 is greater than 0.5 μm and the ratio A to the metal layer 415 is also greater than 0.5, although the roughness Ra and Rz values ​​are greatly improved and the electrode bonding force is also greatly improved, excessive corrosion leads to an increase in sheet resistance, a decrease in conductivity, and a serious decrease in tensile mechanical properties, affecting use. Therefore, it is recommended that the depth of the groove 21 be maintained at 0.1 μm to 0.5 μm and the ratio of the corrosion depth to the metal layer 415 be maintained at 0.1 to 0.5.

[0297] It can be seen from Examples 3, 6 to 10 and Comparative Examples 4 to 5 that when the depth of the groove 21 is kept at 0.3 μm, the corrosion density of the groove 21 can be controlled by controlling the area of ​​the grid 22. 2 When the metal layer 415 of the composite current collector 500 is almost covered by the grid 22, the corrosion density is high, and the corrosive liquid easily overflows, corroding most of the surface metal layer 415, so the roughness is not greatly improved; at the same time, the electrode bonding strength is not greatly improved. However, most of the metal layer 415 is corroded, resulting in the thinning of the metal layer 415 and the increase of the square resistance, while the tensile mechanical properties are reduced. When the area of ​​the grid 22 is larger than 50mm 2 When the corrosion density on the large surface of the metal layer 415 is reduced, the roughness improvement range is limited, and the overall electrode bonding force is not effectively improved. Therefore, the area of ​​the grid 22 is kept at 1mm 2 ~50mm 2 , which can ensure the improvement of roughness without affecting the square resistance, conductivity and mechanical properties of the current collector 500.

[0298] In Examples 11 to 15, it can be seen from Comparative Examples 3, 6, and 7 that when the type of the corrosion portion 20 is a protrusion 23 or a depression 24, in this embodiment, the protrusion 23 is taken as an example. When the corrosion depth is kept at 0.3 μm, the ratio A is 0.3, and the corrosion area is less than 1 mm. 2 When the corrosion area is larger than 50mm, the improvement of roughness is not obvious, and the bonding strength of the electrode is not much improved. 2 When the surface roughness is improved significantly, the bonding strength of the electrode is also effectively improved. However, as the corrosion area increases, the thickness of the comprehensive metal layer 415 decreases and the square resistance increases. At the same time, the mechanical tensile properties decrease significantly. Therefore, it is recommended that the corrosion area be kept at 1mm 2 ~50mm 2 , which can ensure the improvement of roughness without affecting the square resistance, conductivity and mechanical properties of the current collector 500.

[0299] Overall, at the same etching depth, the grooved roller 100 with grooves 21 is more effective for improving roughness than the ridged or recessed sections 23 or 24 etching schemes because the grid 22-shaped etching has a higher density and more uniform etching. However, because it is line etching, the density of the grid 22 is primarily controlled. While maintaining basic mechanical properties and sheet resistance, the roughness improvement capability is greater than that of surface etching, but the etching uniformity of surface etching is worse than that of line etching.

[0300] In summary, the surface treatment device of the composite current collector 500 and the high-roughness composite current collector 500 after treatment disclosed in this patent can not only effectively improve the roughness of the composite current collector 500 without affecting its basic mechanical properties and conductivity, but also greatly improve the bonding force between the current collector 500 and the active material layer, ensuring the reliability of the battery cell under long-term cycle storage, while having the advantage of cost reduction.

[0301] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0302] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

[0303] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0304] 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0305] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0306] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0307] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

Claims

1. A corrosion roller, comprising: The roller body (10) is provided with a conveying channel (11) extending along the direction of its axis (13); The corrosion part (20) is arranged on the roller body (10), and the inner wall of the conveying channel (11) is provided with a discharge hole (12), and the discharge hole (12) extends to the corrosion part (20) and is used to communicate with the outside of the corrosion roller on the corrosion part (20).

2. The erosion roller according to claim 1, wherein: The hole area of ​​the discharge hole (12) is denoted as S1, where 1 mm 2 ≤S1≤10mm 2 .

3. The erosion roller according to claim 2, wherein: The hole area S1 also meets the following conditions: 3mm 2 ≤S1≤7mm 2 .

4. The erosion roller according to any one of claims 1 to 3, wherein: The roller body (10) has a roller surface (14) arranged circumferentially around its own axis (13), and at least part of the corrosion portion (20) is arranged on the roller surface (14).

5. The erosion roller according to any one of claims 1 to 4, wherein: The roller body (10) has a roller surface (14) arranged circumferentially around its own axis (13); at least part of the corrosion portion (20) is arranged inside the roller body (10), and an end away from the conveying channel (11) is not lower than the roller surface (14).

6. The erosion roller according to claim 4 or 5, wherein: The etching portion (20) comprises a groove (21), the groove (21) being arranged inside the roller body (10), and an end thereof away from the conveying channel (11) being not lower than the roller surface (14), and the discharge hole (12) being connected to the outside of the etching roller through the groove (21).

7. The erosion roller according to claim 6, wherein: The dimension of the end of the groove (21) away from the conveying channel (11) in the direction of the axis (13) is smaller than the dimension of the end of the groove (21) close to the conveying channel (11) in the direction of the axis (13).

8. The erosion roller according to claim 7, wherein: The dimension of the end of the groove (21) away from the conveying channel (11) in the direction of the axis (13) is recorded as L1, wherein 0.5 mm≤L1≤1.5 mm.

9. The erosion roller according to claim 8, wherein: The dimension L1 also satisfies the condition: 0.8 mm ≤ L1 ≤ 1.2 mm.

10. The erosion roller according to any one of claims 7 to 9, wherein: The dimension of the end of the groove (21) close to the conveying channel (11) in the direction of the axis (13) is recorded as L2, wherein 2mm≤L2≤5mm.

11. The erosion roller according to claim 10, wherein: The dimension L2 also satisfies the condition: 2.5 mm ≤ L2 ≤ 4 mm.

12. The erosion roller according to any one of claims 6 to 11, wherein: The depth of the groove (21) is denoted as h1, wherein 1 mm ≤ h1 ≤ 5 mm.

13. The erosion roller according to claim 12, wherein: The dimension h1 also satisfies the condition: 2mm≤h1≤4mm.

14. The erosion roller according to any one of claims 6 to 13, wherein: The grooves (21) include a plurality of grooves, and at least a portion of the grooves (21) extend and intersect on the roller surface (14) to enclose and form a plurality of grids (22).

15. The erosion roller according to claim 14, wherein: The area of ​​the grid (22) is denoted as S2, where 1 mm 2 ≤S2≤50mm 2 .

16. The erosion roller according to claim 15, wherein: Area S2 also meets the following conditions: 5mm 2 ≤S2≤30mm 2 .

17. The erosion roller according to any one of claims 4 to 16, wherein: The corrosion portion (20) comprises a protrusion (23), the protrusion (23) is arranged on the roller surface (14), and one end of the discharge hole (12) extends to the surface of the protrusion (23).

18. The erosion roller according to claim 17, wherein: The height of the protruding portion (23) protruding from the roller surface (14) is denoted as h2, wherein 1 mm ≤ h2 ≤ 5 mm.

19. The erosion roller according to claim 18, wherein: The dimension h2 also satisfies the condition: 2mm≤h2≤4mm.

20. The erosion roller according to any one of claims 4 to 16, wherein: The corrosion portion (20) comprises a recessed portion (24), the recessed portion (24) being arranged on the roller surface (14) and recessed toward one side of the conveying channel (11), and one end of the discharge hole (12) extending into the recessed portion (24).

21. The erosion roller according to claim 20, wherein: The depth of the recessed portion (24) is denoted as h3, wherein 1 mm ≤ h3 ≤ 5 mm.

22. The erosion roller according to claim 21, wherein The dimension h3 also satisfies the condition: 2mm≤h3≤4mm.

23. A corrosion device, comprising: Back roller (200); The etching roller according to any one of claims 1 to 22, wherein a metal layer is passed between the etching roller and the backing roller (200).

24. The etching apparatus according to claim 23, wherein: The etching device further comprises a heater, which is used to heat the backing roller (200) and / or the etching roller.

25. The etching apparatus according to claim 23 or 24, wherein: The etching device further comprises a collecting tank (300), wherein the collecting tank (300) is used to recover the etching liquid on the etching roller.

26. A method for processing a metal layer, using the etching device according to any one of claims 23 to 25, the method for processing the metal layer comprising the following steps: Introducing etching liquid into the conveying channel (11) and driving the etching roller to rotate around its own axis (13); The metal layer passing through the etching roller is cleaned and dried.

27. The method for processing a metal layer according to claim 26, wherein: The parameters of the etching solution include at least one of the following: The temperature of the corrosive liquid is 25°C to 80°C; The concentration of the corrosive solution is 80g / L to 120g / L.

28. The method for processing a metal layer according to claim 26 or 27, wherein: The components of the etching solution include at least one of sodium hydroxide, potassium hydroxide, phosphoric acid, acetic acid, nitric acid and sulfuric acid.

29. The method for processing a metal layer according to claim 26 or 27, wherein: The components of the etching solution include compounds containing trivalent iron ions.

30. The method for processing a metal layer according to any one of claims 26 to 29, wherein: The step of cleaning and drying the metal layer passing through the etching roller comprises: washing and extruding the metal layer; The extruded metal layer is cleaned with a polishing liquid; The cleaned metal layer is sequentially washed, squeezed and dried.

31. The method for processing a metal layer according to claim 30, wherein: The light emitting liquid comprises nitric acid, wherein the concentration of the nitric acid is 300 mL / L to 500 mL / L.

32. A metal layer, wherein the metal layer is corroded using the corrosion equipment described in any one of claims 23-25; or, the metal layer is processed using the metal layer processing method described in any one of claims 26-31, and the surface of the metal layer has a corrosion recess (416).

33. The metal layer according to claim 32, wherein The thickness of the metal layer is denoted as h4, and the depth of the corrosion recess (416) is denoted as h5, wherein 0.1≤h5 / h4≤0.

5.

34. The metal layer according to claim 33, wherein The thickness h4 satisfies the condition: 0.7 μm≤h4≤2 μm.

35. The metal layer according to claim 34, wherein The thickness h4 also satisfies the condition: 1 μm≤h4≤1.5 μm.

36. The erosion roller according to any one of claims 32 to 35, wherein: The area of ​​the corrosion concave portion (416) is denoted as S3, where 1 mm 2 ≤S3≤50mm 2 .

37. The erosion roller according to claim 36, wherein: Area S3 also meets the following conditions: 5mm 2 ≤S3≤30mm 2 .

38. The metal layer according to any one of claims 32 to 37, wherein: The roughness of the surface of the metal layer having the corrosion recess (416) satisfies at least one of the following conditions: 0.2 μm≤Ra≤1 μm; 1 μm≤Rz≤3 μm, wherein Ra refers to the average surface roughness of the metal layer, and Rz refers to the overall surface roughness of the metal layer.

39. A current collector, comprising the metal layer according to any one of claims 32 to 38.

40. The current collector according to claim 39, wherein The current collector further comprises a substrate layer (510), the metal layer is arranged on at least one side of the substrate layer (510), and the corrosion recess (416) is arranged on a side of the metal layer facing away from the substrate layer (510).

41. A pole piece, comprising the current collector according to claim 39 or 40.

42. An electrode assembly (413), comprising the electrode piece according to claim 41.

43. A secondary battery (41), comprising the electrode assembly (413) according to claim 42.

44. An electrical device (400), comprising the secondary battery (41) according to claim 43.

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