A detachable diamond-coated tungsten steel lithium battery cutting die

Abstract

The present application belongs to the technical field of lithium battery production equipment, and particularly relates to a diamond coating deposition method and a detachable tungsten steel lithium battery cutting die. The deposition method comprises the following steps: placing a blade insert in carolic acid for decobalt treatment, ultrasonic rinsing with pure water after decobalt is completed, and then activating the surface of the blade insert by plasma etching; placing the pretreated blade insert into a chemical vapor deposition device to deposit a diamond coating under high temperature conditions; cooling down with the furnace after deposition is completed to obtain a blade insert plated with a diamond coating; wherein the initial radius of the blade arc of the blade insert plated with the diamond coating is less than or equal to 3 microns. By depositing a diamond coating on the surface of the blade insert and controlling the initial radius of the blade arc of the blade insert plated with the diamond coating to be within 3 microns, the blade has super-high wear resistance and an extremely low surface friction coefficient, and the number of fault-free cutting times of the die is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of lithium battery production equipment, specifically relating to a diamond coating deposition method and a detachable tungsten steel lithium battery cutting mold. Background Technology

[0002] As a core energy storage device in the new energy industry, lithium batteries rely heavily on the cutting and processing of key materials such as electrodes, multi-layer tabs, and copper and aluminum foil in cell manufacturing. The cutting precision, wear resistance, and service life of the cutting dies directly determine the quality of the tab cross-section and production efficiency, and also have a contagious impact on the quality of subsequent key processes such as tab welding. Therefore, they are core tooling for ensuring the yield rate, manufacturing cost, and electrical performance of lithium batteries.

[0003] Currently, the industry generally uses integrated tungsten steel cutting molds, where the tungsten steel cutting edge and ceramic blade are fixed together by brazing or bonding and cannot be separated. The edge protection coating mostly uses common hard coatings such as TiN and CrN, with a hardness of only 2000-2500 HV. Furthermore, the initial radius of curvature of the cutting edge after coating is generally above 15μm. This structure has several drawbacks: First, after the cutting edge wears down, the entire mold needs to be disassembled for repair, grinding, and coating. The ceramic blade is prone to deformation and cracking due to the high temperature of the coating, resulting in high scrap costs and making it impossible to replace or repair only partially damaged edges. Second, the overall high-temperature re-plating after grinding and repair can cause damage to the ceramic blade. The blade's thermal deformation leads to misalignment of the mold parallelism and punching clearance, resulting in loss of dimensional accuracy after replating. Thirdly, ordinary coatings have low hardness and a high coefficient of friction, making them prone to sticking and rapid wear when cutting soft copper and aluminum foil at high speeds. This results in short mold punching life and frequent downtime for mold repair, leading to a decrease in production line uptime. Fourthly, a large blade radius exacerbates material extrusion deformation during cutting, expanding the plastic deformation zone and increasing residual stress at the edges. This not only increases the burr height but also leads to uneven fusion depth and large fluctuations in welding pull during subsequent electrode welding, increasing the risk of defects such as incomplete welding and desoldering, thus restricting the electrical connection reliability and long-term cycle life of the battery cell.

[0004] In summary, existing integrated cutting dies have several technical problems, including the inability to disassemble and repair the cutting edge separately, the inability to re-coat the coating stably, insufficient wear resistance and anti-stick properties, low cutting edge forming accuracy affecting subsequent welding quality, and high maintenance costs and long cycles. There is an urgent need for a new type of cutting die with a reasonable structure and excellent performance to solve these problems. Summary of the Invention

[0005] The purpose of this invention is to provide a diamond coating deposition method and a suitable detachable cutting die. By depositing a diamond coating on the surface of the cutting edge insert and strictly controlling the initial radius of the cutting edge arc after diamond coating to within 3μm, the cutting edge has ultra-high wear resistance and extremely low surface friction coefficient. This achieves improved cutting quality by increasing the number of fault-free punching operations of the die, eliminating sticking and stringing phenomena in high-speed cutting of soft copper and aluminum foil, and ensuring stable burrs on the tab cross-section.

[0006] The specific technical solution adopted by this invention is as follows: A method for depositing a diamond coating includes the following steps: Stp1: The cutting edge insert is placed in carboxylic acid for cobalt removal treatment. After cobalt removal, it is ultrasonically rinsed with pure water, and then the surface of the cutting edge insert is activated by plasma etching. Stp2: The pre-treated cutting edge insert is placed into a chemical vapor deposition apparatus to deposit a diamond coating under high temperature conditions; Stp3: After deposition, the cutting edge insert is cooled in the furnace to obtain a diamond-coated cutting edge insert. Wherein, the initial radius of the cutting edge arc of the cutting edge insert after being coated with diamond is ≤3μm.

[0007] In a preferred embodiment, in step Stp1, the cobalt removal treatment with carboxylic acid takes 7-15 minutes, the ultrasonic rinsing with pure water takes 3-5 minutes, and the plasma etching uses argon plasma for 5-15 minutes.

[0008] In a preferred embodiment, in step Stp2, the chemical vapor deposition is performed using microwave plasma CVD or hot filament CVD, with a deposition temperature of 700–900°C and a deposition atmosphere of a mixture of methane and hydrogen, with a methane volume fraction of 1%–5%.

[0009] In a preferred embodiment, the diamond coating has a thickness of 0.5 to 1.5 micrometers and a microhardness of ≥7000 HV.

[0010] In a preferred embodiment, the coefficient of friction of the diamond coating is 0.1 to 0.2.

[0011] In a preferred embodiment, the diamond coating is a nanocrystalline diamond film, and the grain size of the diamond coating is 10 to 100 nm.

[0012] In a preferred embodiment, a replating repair step is also included. After the cutting edge on the cutting edge insert becomes dull, the cutting edge insert is removed separately, the cutting edge is ground and repaired, and then steps Stp1 to Stp3 are repeated to deposit diamond coating again, thereby achieving multiple replating repairs.

[0013] A detachable tungsten steel lithium battery cutting mold includes a first mold base and a second mold base. The second mold base is slidably connected to the upper end of the first mold base. A first blade plate is detachably fixed to one side of the top of the first mold base. A first cutting edge insert is detachably fixed to one side of the first blade plate. A second blade plate is detachably fixed to one side of the second mold base. A second cutting edge insert is detachably fixed to the lower end of the second blade plate. The first cutting edge insert and the second cutting edge insert are compatible. A plurality of lifting bolts are slidably connected inside the second mold base. A pressure plate is fixed to the lower end of the plurality of lifting bolts. Wherein, the first blade and the second blade are both made of at least one of the following materials: alumina and silicon carbide; the first cutting edge insert and the second cutting edge insert are both made of WC-Co cemented carbide; and the surfaces of the first cutting edge insert and the second cutting edge insert are formed with a diamond coating by any one of the diamond coating deposition methods described above.

[0014] The technical effects achieved by this invention are as follows: This invention deposits a diamond coating with a microhardness ≥7000HV on the surface of the cutting edge insert and strictly controls the initial radius of the cutting edge arc after diamond coating to within 3μm. This results in the cutting edge having ultra-high wear resistance and extremely low surface friction coefficient, which significantly reduces the amount of extrusion plastic deformation of copper and aluminum foil and multi-layer tabs during the cutting process. The work-hardened layer of the cross-section and the residual stress at the edge are reduced simultaneously. This achieves a full-process quality improvement effect with lower burrs on the cutting surface of the tabs, higher forming accuracy, better consistency of subsequent tab welding tensile force, and a significant reduction in the risk of false welding. It also achieves improved cutting quality by increasing the number of fault-free punching times of the mold, eliminating sticking and stringing phenomena in high-speed cutting of soft copper and aluminum foil, and stabilizing the burrs on the tab cross-section. This invention designs the first and second cutting edge inserts as detachable insert structures and locks them onto the first and second ceramic cutting plates with screws. This allows the cutting edges to be disassembled separately after wear for grinding, refining, and multiple secondary diamond replating. The first and second ceramic cutting plates do not participate in the high-temperature coating process. This achieves a comprehensive effect of reducing the overall material cost of the mold, shortening downtime for maintenance, increasing the service life of the ceramic cutting plates, ensuring long-term stability of dimensional accuracy such as mold flatness and parallelism, and adapting to the cutting conditions of all types of lithium batteries, from single-layer copper and aluminum foil to multi-layer tabs. Attached Figure Description

[0015] Figure 1 This is a flow chart of the diamond coating deposition process in Embodiment 1 of the present invention; Figure 2 These are electron microscope comparison images of the diamond coating in Embodiment 1 of the present invention and the prior art; Figure 3These are electron microscope comparison images of the cutting edge of the insert in Embodiment 1 of the present invention and that of the prior art; Figure 4 This is an electron microscope image of the first deposition of a diamond coating on the cutting edge insert in Embodiment 5 of the present invention. Figure 1 ; Figure 5 This is an electron microscope image of the first deposition of a diamond coating on the cutting edge insert in Embodiment 5 of the present invention. Figure 2 ; Figure 6 This is an electron microscope image of the diamond-coated cutting edge insert when it is discarded, as described in Embodiment 5 of the present invention. Figure 1 ; Figure 7 This is an electron microscope image of the diamond-coated cutting edge insert when it is discarded, as described in Embodiment 5 of the present invention. Figure 2 ; Figure 8 This is a schematic diagram of the overall structure in Embodiment Seven of the present invention; Figure 9 This is an exploded view of the overall structure in Embodiment Seven of the present invention; Figure 10 This is a schematic diagram of the structure of the second blade and the second cutting edge insert in Embodiment 7 of the present invention; Figure 11 This is a schematic diagram of the structure of the first blade and the first cutting edge insert in Embodiment 7 of the present invention; The attached diagram lists the components represented by each number as follows: 10. First mold base; 11. First blade plate; 12. First cutting edge insert; 20. Second mold base; 21. Second blade plate; 22. Second cutting edge insert; 31. Hanger bolt; 32. Pressure plate. Detailed Implementation

[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0017] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0018] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in a preferred embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that mutually excludes other embodiments.

[0019] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include the three-dimensional spatial dimensions of length, width, and depth.

[0020] Example 1

[0021] Please see Figure 1 As shown, this embodiment provides a diamond coating deposition method using plasma CVD technology. Specifically: A WC-Co cemented carbide cutting edge insert was selected as the substrate. The insert was statically immersed in carboxylic acid for 10 minutes to remove cobalt. After cobalt removal, it was removed and ultrasonically rinsed with deionized water for 4 minutes to remove cobalt salts, grinding debris, and other impurities from the cutting edge surface. After rinsing and drying, it was placed in a plasma etching apparatus. Argon plasma was used to etch and activate the cutting edge surface for 10 minutes at a power of 200W to remove the surface oxide layer, increase surface roughness, and improve coating adhesion. The activated cutting edge insert was then placed separately in a microwave plasma chemical vapor deposition apparatus. The vacuum was reduced to below 10 Pa, hydrogen gas was introduced, and the temperature was raised to 850°C and held for 10 minutes for further surface reduction treatment. Methane gas was introduced, with the methane volume fraction controlled at 3%, and the working pressure adjusted to 5 kPa. Diamond deposition was performed at 850℃ for 8 hours, resulting in a diamond coating with a thickness of approximately 4.5 μm. After deposition, the methane supply was stopped, and the furnace was cooled to room temperature under a hydrogen atmosphere. The tungsten carbide cutting edge insert coated with the diamond coating was then removed. The diamond coating deposited using the above process exhibited a polycrystalline nanodiamond structure with a grain size of approximately 30–50 nm. The coating had a microhardness of approximately 7800 HV and a coefficient of friction of approximately 0.15. Electron microscopy revealed that the diamond grains were uniform and dense, without obvious porosity or detachment defects, and exhibited good adhesion to the substrate. The initial radius of the cutting edge after coating was 2 μm (e.g., ...). Figure 2 and Figure 3 (As shown).

[0022] in, Figure 2 Image a is an electron microscope image of the surface coating of a cutting blade in the prior art. Figure 2 Image b is an electron microscope image of the surface coating of the cutting edge insert after diamond coating in this embodiment. Figure 3 In the diagram, 'a' represents the initial radius of the cutting edge of a cutting blade after coating in the prior art. Figure 3 In this embodiment, b is a schematic diagram showing the initial radius of the cutting edge arc of the cutting edge insert after being coated with diamond; through Figure 2As can be seen from a, in the existing technology, the coating on the surface of the cutting blade has large, loosely arranged grains and obvious porosity defects. Figure 2 As can be seen from b, the diamond coating obtained in this embodiment has finer and more uniform grains, and higher density. Comparatively, the fine and uniform grain structure provides more stable support for the cutting edge, ensuring a smaller radius of curvature after grinding and slowing down grain shedding during long-term punching, thus delaying edge wear. Simultaneously, the smaller radius of curvature reduces the amount of material deformation during cutting, preventing excessive burrs on the edge of the electrode lugs and effectively improving the forming quality of the cut surface. Figure 3 As can be seen from a, in the existing technology, the initial radius of the cutting edge of the cutting blade after being coated with a diamond coating reaches 18.42 μm. Figure 3 As can be seen from b, the radius of the cutting edge obtained in the embodiment is smaller, only 2μm. In comparison, in this embodiment, the cutting edge insert coated with diamond coating requires less shearing force to cut the material during punching, and the degree of compression on the lithium battery electrode or tab during the cutting process is less. The cut surface is flatter and has fewer burrs, which can meet the quality requirements of high-precision tab cutting for power batteries.

[0023] It should be noted that in this embodiment, a three-step pretreatment process combining cobalt removal with pure water ultrasonic rinsing and plasma etching is used to remove free cobalt from the surface of the cemented carbide, effectively purifying and activating the cutting edge surface, and providing a good interface foundation for diamond nucleation. By controlling the CVD deposition temperature and atmosphere parameters, a high-purity, high-density diamond film is generated on the tungsten carbide surface. Utilizing the ultra-high hardness and extremely low coefficient of friction of diamond, the wear resistance and anti-sticking performance of the cutting edge are significantly improved, making it suitable for high-speed cutting of copper and aluminum foil and multi-layer tabs in lithium batteries.

[0024] Furthermore, the carboxylic acid is a persulfate solution, and static soaking is used during the cobalt removal stage without ultrasonic treatment; ultrasonic treatment is only used in the rinsing process after cobalt removal to avoid accelerating the decomposition and failure of the carboxylic acid.

[0025] Example 2

[0026] This embodiment provides a diamond coating deposition method using a hot-wire CVD process, specifically: A WC-Co cemented carbide cutting edge insert was selected as the substrate. The insert was statically immersed in carboxylic acid for 8 minutes to remove cobalt. After cobalt removal, it was removed and ultrasonically rinsed with deionized water for 3 minutes to remove surface cobalt salts and debris. After rinsing, it was removed, dried, and placed in a plasma etching apparatus. Argon plasma etching was performed for 8 minutes at an etching power of 180W. The activated tungsten carbide insert was placed in a hot-wire chemical vapor deposition apparatus. After vacuuming, hydrogen gas was introduced, and the temperature was raised to 800℃ and held for 15 minutes. Methane gas was introduced, with the methane volume fraction controlled at 2% and the working pressure at 3 kPa. Deposition was carried out at 800℃ for 10 hours to obtain a diamond coating with a thickness of about 5 μm. After deposition, it was cooled and removed with the furnace. The diamond coating deposited by the above process has a microhardness of about 7500 HV and a coefficient of friction of about 0.18.

[0027] Example 3

[0028] This embodiment provides a diamond coating replating repair process, the specific steps of which are as follows: The passivated cutting edge insert is removed separately from the cutting tool plate, and the cutting edge on the insert is precision ground to remove the wear layer and residual coating, restoring the geometric accuracy of the cutting edge. The ground cutting edge insert is statically immersed in carboxylic acid for 12 minutes to remove cobalt. After cobalt removal, it is removed and ultrasonically rinsed with deionized water for 5 minutes to remove grinding debris and surface free cobalt. Then, it is surface activated by argon plasma etching for 12 minutes. The activated insert is placed in a microwave plasma CVD equipment, and a diamond coating is redeposited according to the process parameters in Example 2, with the coating thickness controlled at 1.5 μm. After deposition, it is cooled in the furnace and removed, then reassembled onto the ceramic cutting tool plate for continued use.

[0029] Example 4

[0030] Please see Figures 4 to 7 As shown, this embodiment provides a cutting scenario for a single-layer thin copper foil, which is a parameter variation of Embodiment 2, as detailed below: A cutting edge insert for cutting ultrathin electrolytic copper foil with a thickness of 0.7 mm was selected. The substrate was WC-Co cemented carbide, and the cutting edge roughness Ra ≤ 0.05 μm. The cutting edge insert was statically immersed in carboxylic acid for 9 min to remove cobalt. After cobalt removal, it was removed and ultrasonically rinsed with deionized water for 4 min. Then, it was etched and activated by argon-hydrogen mixed plasma for 12 min at an etching power of 220 W. A diamond coating was deposited using microwave plasma CVD at a deposition temperature of 820℃, a methane volume fraction of 2.5%, a working pressure of 4 kPa, and a deposition time of 6 h to obtain a nanodiamond coating with a thickness of approximately 1 μm (e.g., ...). Figure 4 and Figure 5After cooling in the furnace, it is removed and assembled onto the alumina ceramic blade. The positioning pin is locked diagonally with four M3 hex socket screws. The single-sided punching clearance is 0.055mm. Mass production test results: after 500,000 continuous punchings of 0.7mm ultra-thin copper foil, the cutting edge shows slight wear, and the burr on the cross-section is stable at 12-17μm. There is no copper foil sticking to the blade or wire drawing. After the cutting edge is dulled, it is disassembled and ground separately, and then re-plated with a 1.5μm diamond coating. The ceramic blade does not participate in the high-temperature process at all. After reassembly, the parallelism deviation is ≤0.001mm, and the punching performance is restored to the level of a new product. After a single cutting edge insert is repeatedly ground and re-plated 5 times, the total punching life exceeds 2.6 million cycles (e.g. Figure 6 and Figure 7 The ceramic blade was free from deformation and cracking.

[0031] Example 5

[0032] This embodiment provides a cutting scenario for an 80-layer copper-aluminum composite electrode, which is a parameter variation of Embodiment 2, as follows: Each of the upper and lower dies is equipped with three sets of tungsten carbide cutting edge inserts. Each set of inserts has two Φ2.5 locating pins and four M3 hexagon socket head cap screws, with a positioning accuracy of ≤0.002mm. The cutting edge inserts undergo individual diamond coating preparation. Pretreatment involves static immersion in carboxylic acid for 11 minutes to remove cobalt, ultrasonic rinsing with deionized water for 3 minutes, and oxygen plasma etching for 8 minutes to remove free cobalt phase from the surface. Deposition is performed using a DC arc plasma CVD process at a deposition temperature of 780℃ and a methane volume fraction of 4%. After 9 hours, the diamond coating thickness is about 1μm, and the coating microhardness is about 7200HV; after assembly, the overall parallelism of the mold is ≤0.003mm, and the punching gap is uniform; mass production test results: 80 layers of copper-aluminum composite tab copper foil and aluminum foil are stacked alternately and continuously punched at high speed for 450,000 times without obvious chipping, the burr on the cross-section is controlled at 13~19μm, and there is no tearing or misalignment between layers; after a total of 3 grinding and replating, the coating adhesion test is ≥60N, with no peeling or delamination, and the product yield after reassembly is stable at over 99.5%.

[0033] Example 6

[0034] This embodiment corresponds to the scenario of cutting 110-layer pure aluminum foil tabs, and is a parameter variation of Embodiment 3, as detailed below: The cutting edge insert is made of WC-6Co ultrafine-grained cemented carbide, and the cutting edge is mirror-polished. The pretreatment steps are: ultrasonic degreasing with alkaline cleaning agent for 10 min, rinsing with deionized water, static immersion in carboxylic acid to remove cobalt for 13 min, ultrasonic rinsing with deionized water for 4 min, and argon plasma etching for 10 min. A diamond coating is deposited using hot-wire CVD process, with a hot-wire temperature of 2200℃, a substrate temperature of 750℃, a methane volume fraction of 1.5%, a working pressure of 2.5 kPa, and a deposition time of 12 h. A microcrystalline diamond coating with a thickness of approximately 1.5 μm and a grain size of approximately 80 nm was obtained, with a friction coefficient of approximately 0.17. Mass production test results: 110 layers of pure aluminum foil tabs were continuously punched 520,000 times, with a cutting edge wear of ≤1 μm. The cut surface of the aluminum foil was bright and burr-free, with initial burrs of 4-7 μm. Compared with TiN coated molds under the same working conditions, the burr excess defect rate was reduced by 78%. After 4 grinding and replating cycles, the dimensional accuracy of the inserts still met the mass production requirements, and the ceramic blades showed no deformation or cracking after 8 months of use.

[0035] Example 7

[0036] Please see the appendix Figures 8 to 11 As shown, this embodiment provides a detachable tungsten steel lithium battery cutting mold, including a first mold base 10 and a second mold base 20. The second mold base 20 is slidably connected to the upper end of the first mold base 10. A first blade plate 11 is detachably fixed to one side of the top of the first mold base 10 by bolts. A first cutting edge insert 12 is detachably fixed to one side of the first blade plate 11 by bolts. A second blade plate 21 is detachably fixed to one side of the second mold base 20 by bolts. A second cutting edge insert 22 is detachably fixed to the lower end of the second blade plate 21 by bolts. The first cutting edge insert 12 and the second cutting edge insert 22 are connected to each other. The second mold base 20 is internally slidably connected with multiple lifting bolts 31, and the lower ends of the multiple lifting bolts 31 are fixed with pressure plates 32. The first cutting edge insert 12 and the second cutting edge insert 22 are both provided with cutting edges, and the cutting edge on the first cutting edge insert 12 is adapted to the cutting edge on the second cutting edge insert 22. The surfaces of the first cutting edge insert 12 and the second cutting edge insert 22 are both coated with diamond coating using the diamond coating deposition process in Example 1. The initial radius of the cutting edge arc of the first cutting edge insert 12 and the second cutting edge insert 22 after being coated with diamond coating is ≤3μm.

[0037] It should be noted that the first blade 11 and the second blade 21 are made of at least one of the following materials: alumina, silicon carbide or other ceramic materials, and the first cutting edge insert 12 and the second cutting edge insert 22 are both made of WC-Co cemented carbide. In this embodiment, the first blade 11 and the second blade 21 are preferably made of alumina.

[0038] Furthermore, a stamping device is used in conjunction with the apparatus. The stamping device includes at least a lower platform and an upper platform. The first die holder 10 can be fixed to the upper end of the lower platform with bolts, and the second die holder 20 can be fixed to the lower end of the upper platform with bolts. After the upper platform moves vertically, it can drive the second die holder 20 to move synchronously. During production, the upper platform drives the second die holder 20 and the pressure plate 32 to move upward to change to the open die state, conveying materials (such as lithium battery electrodes, multilayer tabs, copper and aluminum foil). After reaching the upper surface of the first cutting edge insert 12, the upper machine table drives the second die base 20 and the pressure plate 32 to move downward. The pressure plate 32 first contacts the material and squeezes the material to achieve the purpose of pressing the material. The second cutting edge insert 22 then contacts the material, and the material is cut by the cooperation of the first cutting edge insert 12 and the second cutting edge insert 22. Specifically, the stamping equipment and cutting process are existing mature applications, and their specific working process can be referred to the existing technology. Here, no further details will be made.

[0039] In this embodiment, when the cutting edges on the first cutting edge insert 12 and / or the second cutting edge insert 22 become dull, the first cutting edge insert 12 and / or the second cutting edge insert 22 are removed from the device. First, the cutting edge is ground and repaired. After the repair is completed, a diamond coating deposition process is performed to re-plat and repair the diamond coating on the first cutting edge insert 12 and / or the second cutting edge insert 22. After the repair is completed, the first cutting edge insert 12 and / or the second cutting edge insert 22 are installed and fixed. Finally, the gap is adjusted. After adjustment, the device is ready for use. When production resumes, the above-mentioned scheme allows for shorter maintenance cycles after the cutting edge becomes dull, improving production line uptime. Only the first cutting edge insert 12 and / or the second cutting edge insert 22 need to be disassembled for inspection, grinding, and coating. The entire set of equipment does not need to be disassembled and transported, reducing downtime for maintenance by 70%. The effective production time of the production line is significantly increased, reducing the cost of cutting edge maintenance. Furthermore, the first cutting edge 11 and the second cutting edge 21 do not enter the high-temperature coating furnace during the cutting edge repair process, avoiding heat deformation and cracking of the ceramic first cutting edge 11 and the second cutting edge 21.

[0040] In this embodiment, the nanocrystalline diamond structure has finer grains and a higher coating density, while also having a lower coefficient of friction and higher surface hardness. Compared with traditional cutting edges, the service life of the first blade 11 and the first cutting edge insert 12 can be increased by more than 3 times, and the service life of the first cutting edge insert 12 and the second cutting edge insert 22 can be increased by 2 to 3 times. Moreover, it is not easy for material to stick during cutting, and the cut is smoother. It can effectively improve the yield of cutting operations, and is far superior to TiN and CrN coatings (2000-2500HV). There is no rapid wear when continuously cutting copper and aluminum foil at high speed. Under the same working conditions, the number of fault-free punching times of the mold is increased by more than 120%.

[0041] In summary, in the above embodiments, by designing the tungsten carbide cutting edge inserts as detachable insert structures (i.e., the first cutting edge insert 12 and the second cutting edge insert 22) and fixing them to the ceramic cutting edge plates (i.e., the first cutting edge plate 11 and the second cutting edge plate 21) with screws, the cutting edge can be disassembled separately for grinding and re-grinding after wear, and multiple secondary diamond re-plating processes can be performed. The ceramic cutting edge plates do not participate in the high-temperature coating process throughout the entire process, achieving a 60% reduction in overall mold consumable costs, a 70% reduction in downtime maintenance, and a more than 3-fold increase in the service life of the ceramic cutting edge plates. It boasts long-term stable dimensional accuracy in terms of flatness and parallelism, and is suitable for cutting all types of lithium batteries, from single-layer copper and aluminum foil to multi-layer tabs. Furthermore, by depositing a diamond coating with a microhardness ≥7000HV and a friction coefficient of 0.1~0.2 on the surface of the detachable tungsten steel cutting edge insert, the cutting edge exhibits ultra-high wear resistance and an extremely low surface friction coefficient. This results in a more than 120% increase in the number of fault-free punching operations for the mold, high-speed cutting of soft copper and aluminum foil without sticking or stringing, and a stable cutting quality improvement of ≤7μm burrs on the tab cross-section.

[0042] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention are implemented according to conventional methods in the art unless otherwise specified or limited.

Claims

1. A method for depositing a diamond coating, characterized in that: Includes the following steps: Stp1: The cutting edge insert is placed in carboxylic acid for cobalt removal treatment. After cobalt removal, it is ultrasonically rinsed with pure water, and then the surface of the cutting edge insert is activated by plasma etching. Stp2: The pre-treated cutting edge insert is placed into a chemical vapor deposition apparatus to deposit a diamond coating under high temperature conditions; Stp3: After deposition, the cutting edge insert is cooled in the furnace to obtain a diamond-coated cutting edge insert. Wherein, the initial radius of the cutting edge arc of the cutting edge insert after being coated with diamond is ≤3μm.

2. The diamond coating deposition method according to claim 1, characterized in that: In step Stp1, the cobalt removal treatment with carboxylic acid takes 7-15 minutes, the ultrasonic rinsing with pure water takes 3-5 minutes, and the plasma etching uses argon plasma for 5-15 minutes.

3. The diamond coating deposition method according to claim 1, characterized in that: In step Stp2, the chemical vapor deposition is performed using microwave plasma CVD or hot filament CVD, with a deposition temperature of 700–900°C and a deposition atmosphere of a mixture of methane and hydrogen, with a methane volume fraction of 1%–5%.

4. The detachable diamond-coated tungsten steel lithium battery cutting mold according to claim 1, characterized in that: The diamond coating has a thickness of 0.5 to 1.5 micrometers and a microhardness of ≥7000 HV.

5. A detachable diamond-coated tungsten steel lithium battery cutting die according to claim 1, characterized in that: The coefficient of friction of the diamond coating is 0.1 to 0.

2.

6. A detachable diamond-coated tungsten steel lithium battery cutting mold according to claim 1, characterized in that: The diamond coating is a nanocrystalline diamond film, and the grain size of the diamond coating is 10-100 nm.

7. The diamond coating deposition method according to claim 1, characterized in that: It also includes a replating repair step. When the cutting edge on the cutting edge insert becomes dull, the cutting edge insert is removed separately, the cutting edge is ground and repaired, and then steps Stp1 to Stp3 are repeated to deposit diamond coating again to achieve multiple replating repairs.

8. A detachable tungsten carbide lithium battery cutting mold, characterized in that: The first mold base (10) and the second mold base (20) are slidably connected to the upper end of the first mold base (10). A first blade plate (11) is detachably fixed to one side of the top of the first mold base (10). A first cutting edge insert (12) is detachably fixed to one side of the first blade plate (11). A second blade plate (21) is detachably fixed to one side of the second mold base (20). A second cutting edge insert (22) is detachably fixed to the lower end of the second blade plate (21). The first cutting edge insert (12) and the second cutting edge insert (22) are adapted to each other. A plurality of lifting rod bolts (31) are slidably connected inside the second mold base (20). A pressure plate (32) is fixed to the lower end of the plurality of lifting rod bolts (31). Wherein, the first blade (11) and the second blade (21) are made of at least one of the following materials: alumina and silicon carbide; the first cutting edge insert (12) and the second cutting edge insert (22) are both made of WC-Co cemented carbide; the surfaces of the first cutting edge insert (12) and the second cutting edge insert (22) are formed with diamond coating by the diamond coating deposition method according to any one of claims 1 to 7.

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