Preparation method of porous copper foil with regular polygonal hole array

Abstract

The invention provides a preparation method of a porous copper foil with a regular polygonal hole array, which comprises the following steps of: grinding and polishing a titanium plate until the titanium plate is matte, punching holes with the regular polygonal hole array in the titanium plate by laser, finely trimming vertex angles of the regular polygonal holes by laser, and polishing and grinding the titanium plate to obtain the porous copper foil with the regular polygonal hole array. The method comprises the following steps: preparing a titanium plate, cleaning with pure water and alcohol to obtain a clean titanium plate, preparing a copper sulfate electrolyte, adding a proper amount of a brightener, a wetting agent and a high resistance agent into the electrolyte, mixing, pouring the mixed solution into an electrolytic bath, putting the clean titanium plate and a carbon plate into the electrolytic bath, and carrying out electrolytic foil generation by taking the titanium plate as a cathode and the carbon plate as an anode; and after foil generation is finished, the copper foil is stripped from the surface of the titanium plate, and the porous copper foil with the regular polygon holes is obtained. According to the method, the holes of the titanium plate are the regular polygon holes, and the vertex angles of the regular polygon holes are finely trimmed, so that the copper foil of the electrolytic raw foil is not easy to adhere to the titanium plate during stripping, and the production yield of the copper foil is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of porous copper foil, and particularly relates to a method for preparing a porous copper foil with a regular polygonal hole array. BACKGROUND

[0002] With the vigorous development of the new energy industry, the market demand for lithium ion batteries is increasing, and higher performance requirements are also put forward for lithium ion batteries. As the negative current collector in lithium ion batteries, copper foil bears the dual functions of electron transmission and active material support, and its performance directly affects the energy density, safety and cycle life of the battery. With the breakthrough of silicon-carbon negative electrode and solid-state battery technologies, traditional copper foil faces challenges in terms of anti-expansion and current uniformity, and structural innovation is urgently needed to meet the demand for high-performance lithium batteries.

[0003] Using porous copper foil as the negative current collector material of lithium ion batteries can greatly improve the performance of lithium ion batteries: under the same thickness, the porous copper foil is lighter in mass, which can reduce the overall mass of the battery; the porous copper foil has a large specific surface area, which increases the coating area of the negative electrode and can carry more active materials, thereby improving the energy density of the lithium ion battery; the porous structure also increases the wettability of the active material and improves the adhesion of the active material, which can improve the cycle life of the lithium ion battery; in addition, the pore structure of the porous copper foil provides a buffer space for the volume expansion of the silicon-carbon negative electrode and the growth of lithium dendrites, thereby improving the safety of the battery. Porous copper foil will be one of the important directions for the development of copper foil current collectors in the future.

[0004] The current mainstream technology routes for porous copper foil include template method, dealloying method, and powder sintering method: the template method prepares a template on the cathode by coating or granulating, then deposits copper on the template by electrodeposition, and then removes the template to obtain a porous copper foil. This method has low cost, but the process of preparing the template and removing the template is complex; the dealloying method uses the different reactivity of different metals in the alloy to remove the active metal in the alloy by corrosion, thereby obtaining a porous copper foil. This method is simple, but the obtained porous copper foil has poor pore uniformity and low mechanical strength; the powder sintering method mixes copper powder with additives, and then prepares a porous copper foil with a certain porosity by pressing, drying and sintering. This method is also relatively simple, but the porosity uniformity is poor and impurities are easily introduced.

[0005] Based on the current demand of high energy density, high cycle life, high safety of lithium ion battery, and the problems in the existing technology route in the preparation of porous copper foil, most of the existing technology is to obtain a titanium plate with a circular hole array by laser drilling on the titanium plate, and to prepare a porous copper foil with a circular hole array by depositing copper on the porous titanium plate. However, when the circular hole is peeled off, the contact position between the copper foil and the titanium plate is wide, which easily causes the copper foil to stick to the titanium plate when the foil is peeled off. Since the copper foil is thin, the sticking of the copper foil easily causes the copper foil to break when the foil is peeled off. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a method for preparing a porous copper foil with a regular polygonal hole array, which aims to solve the technical problem of low production efficiency caused by the difficulty of peeling off the circular porous copper foil from the titanium plate after electrolytic foil growth, and the damage of the copper foil caused by the sticking of the copper foil to the titanium plate due to the circular hole edge.

[0007] In order to achieve the above-mentioned purpose, the present application is realized by the following technical scheme: A method for preparing a porous copper foil with a regular polygonal hole array, the preparation method comprising the following steps: S1, polishing the surface of the titanium plate to matte; S2, using computer-aided drawing to draw a punching drawing, the shape of the hole in the drawing is a regular polygon, wherein the edge distance of the hole and the spacing between adjacent holes are determined according to the void ratio; S3, according to the drawing, using a laser device to drill holes on the polished side of the titanium plate, the depth of the hole is controlled by the wavelength and the processing time of the laser, wherein the regular polygonal vertex angle of the hole is further refined by the laser device; S4, polishing the surface of the titanium plate to remove the irregular structures generated on the surface of the titanium plate by laser, and cleaning the surface of the titanium plate with pure water and alcohol; S5, configuring a copper sulfate electrolyte, and adding an appropriate amount of brightener, wetting agent and high resistance agent to the electrolyte; S6, pouring the electrolyte into an electrolytic cell, and placing a carbon plate and the titanium plate in the S4 step into the electrolytic cell, and fixing the carbon plate and the titanium plate; S7, taking the titanium plate as a cathode and the carbon plate as an anode to perform electrolytic foil growth, and after the foil growth is completed, peeling off the copper foil from the surface of the titanium plate to obtain a porous copper foil with a regular polygonal hole.

[0008] Compared with the prior art, the beneficial effects of the present application are that: the titanium plate is punched with a positive polygonal hole array by laser, and then the vertex angle of the positive polygonal hole is finely processed, and after the titanium plate with the positive polygonal hole is electrolyzed, a copper foil with a positive polygonal hole is generated, compared with the traditional circular hole, the copper foil with the positive polygonal hole has a small contact area with the titanium plate, and is not easy to appear the phenomenon of sticking foil, so that the copper foil with the positive polygonal hole is more labor-saving in the peeling process of stripping, and will not be damaged due to sticking foil, and the integrity of the copper foil is more easily guaranteed, thereby improving the productivity.

[0009] According to an aspect of the above technical solution, in the S1 step, the thickness of the titanium plate is 3-10mm, and the surface roughness Ra of the polished titanium plate is <0.3μm.

[0010] According to an aspect of the above technical solution, in the S2 step, the hole of the positive polygonal shape is a positive regular polygon, the edge distance of the positive polygonal hole is 20-150mm, the distance between adjacent positive polygonal holes is 40-300μm, and the array is formed by arranging a plurality of positive polygonal holes.

[0011] According to an aspect of the above technical solution, in the S3 step, the wavelength of the laser is 200-800nm, the laser spot size is 6-30μm, the punching time is 0.5-5min, and the punching depth is 5-50μm.

[0012] According to an aspect of the above technical solution, the wavelength of the laser is 300-350nm, the laser spot size is 10-15μm, the punching time is 1-2min, and the punching depth is 10-20μm.

[0013] According to an aspect of the above technical solution, the vertex angle of the hole is further finely processed by the laser equipment, and the processing step includes setting the wavelength of the laser equipment to 200-350nm, the laser spot size to 6-15μm, and then sharpening the vertex angle of the positive polygonal hole.

[0014] According to an aspect of the above technical solution, in the step S4, the surface roughness Ra of the titanium plate is <0.3μm, and Rz is <3.0μm, wherein Rz is the maximum height of the profile.

[0015] According to an aspect of the above technical solution, in the step S5, the copper sulfate electrolyte has a copper ion concentration of 80-100g / L, a sulfuric acid concentration of 100-120g / L, a chloride ion concentration of 20-30ppm, and an electrolyte temperature of 50-60℃.

[0016] According to an aspect of the above technical solution, in the step S5, the brightener is one or more of sodium polydithiopropyl sulfone, 3-mercapto-1-propane sulfonic acid sodium, N, N-dimethyl dithiocarbamic acid propane sulfonic acid sodium and isothiourea propane sulfonic acid inner salt; the wetting agent is one or more of polyethylene glycol, collagen, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, gelatin, fatty alcohol polyoxyethylene ether sulfonated succinic acid monoester disodium; the high resistance agent is one or more of tetrahydrothiazole thione, polyethyleneimine, 2-mercaptobenzimidazole, ethylene thiourea, and the concentrations of the brightener, the wetting agent and the high resistance agent are respectively: brightener 2-10ppm, wetting agent 3-15ppm, high resistance agent 0.5-3ppm.

[0017] According to an aspect of the above technical solution, in the step S7, the current during electrolytic foil production is 20-25A, the plating time is 55-60s, and the copper foil thickness is 6-8μm. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a schematic diagram of the polygonal hole structure of the titanium plate in the first embodiment of the application; Figure 2 It is a schematic diagram of the local structure of the polygonal hole of the titanium plate in the first embodiment of the application; Figure 3 It is an ultra-depth-of-field 3D microscope graph of the polygonal hole array region of the titanium plate in the first embodiment of the application; Figure 4 It is an ultra-depth-of-field 3D microscope graph of the local polygonal hole array region of the titanium plate in the first embodiment of the application; Figure 5 It is an ultra-depth-of-field 3D microscope graph of the porous copper foil with polygonal hole array in the first embodiment of the application; Figure 6 It is an ultra-depth-of-field 3D microscope graph of the local enlarged porous copper foil with polygonal hole array in the first embodiment of the application; Figure 7 It is an ultra-depth-of-field 3D microscope graph of the circular hole array region of the titanium plate in the second comparative embodiment of the application; Figure 8 It is an ultra-depth-of-field 3D microscope graph of the local enlarged porous copper foil with circular hole array in the second comparative embodiment of the application; Figure 9 It is an ultra-depth-of-field 3D microscope graph of the polygonal hole array region of the titanium plate in the third comparative embodiment of the application; Figure 10 It is an ultra-depth-of-field 3D microscope graph of the local enlarged porous copper foil with polygonal hole array in the third comparative embodiment of the application; Explanation of key component symbols: 1-Titanium plate, 11-Wide edge, 2-Regular polygonal hole, 21-Center line, 22-Vertex corner, 23-Edge center distance, 24-Spacing; The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0019] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0020] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] The present invention provides a method for preparing porous copper foil with a regular polygonal hole array, comprising the following steps: S1, polish the surface of titanium plate 1 to a matte finish; Before polishing, a suitable size of titanium plate 1 is selected. In this embodiment, the titanium plate 1 is selected with a length of 10-20cm, a width of 5-10cm, and a thickness of 3-10mm. Then, the side of the titanium plate 1 is polished to a matte state. More specifically, one side of the titanium plate 1 is polished to a roughness Ra<0.3μm.

[0023] S2, using computer-aided drawing to create a hole pattern, wherein the shape of the hole in the pattern is drawn as a regular polygon, and the center-to-side distance 23 and the spacing 24 between adjacent holes are determined according to the porosity. The computer-aided drawing of the perforated drawing paper is drawn, for example, by CAD software, wherein the shape of the holes in the drawing paper is arranged in the form of an array of regular polygons, wherein in the embodiment, the regular polygon hole is selected as a regular hexagonal hole, and the edge center distance 23 of the regular hexagonal hole 2 and the interval 24 of adjacent holes are determined according to the porosity; it is found through experiments that when the edge center distance 23 of the regular polygon hole 2 is 20-150mm and the interval 24 is 40-300μm, the porosity of the generated porous copper foil is optimal, which can carry more active substances and increase the infiltration effect of the active substances. Of course, other regular polygons can also be used, such as regular triangles, rhombuses, regular pentagons, etc.; it is found through experimental tests that the porous copper foil produced by the regular hexagonal hole 2 has the best close-packing property, and the integrity of the copper foil hole is best guaranteed when the foil is peeled off, so the regular hexagonal hole 2 is selected as a representative for explanation and description in this embodiment.

[0024] S3, according to the drawing, holes are made on the polished side of the titanium plate 1 by using a laser device, and the depth of the holes is controlled by the wavelength of the laser and the laser processing time, wherein the top angle 22 of the regular polygon hole is further refined by the laser device; Specifically, the prepared drawing is imported into the laser device, and then the laser device is set so that the wavelength of the laser for punching is between 200-800nm, the size of the laser spot is between 6-30μm, the punching time is between 0.5-5min, and the punching depth is between 5-50μm. After setting, the polished side of the titanium plate 1 is punched. It can be understood that in this embodiment, the wavelength of the laser is typically between 200-800nm but is not limited, i.e. the wavelength of the laser can be 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, and any value in the range formed by any two of these point values. Similarly, the size of the laser spot can be set to 6μm, 7μm, 8μm, 9μm, 10μm, 20μm, 30μm, and any value in the range formed by any two of these point values; the punching time can be 0.5min, 1min, 2min, 3min, 4min, 5min, and any value in the range formed by any two of these point values; It is worth noting that after the punching of one side of the titanium plate 1 is completed, in order to prevent the contact area between the generated copper foil and the titanium plate 1 from being too large and affecting the separation during the foil stripping, the sharp corner 22 of the regular hexagon of the titanium plate 1 after punching is processed. Specifically, the wavelength of the laser equipment is set to 200-350 nm, the laser spot size is 6-15 μm, and the sharp corner 22 of the regular hexagon hole 2 is processed. By processing the sharp corner 22 of the regular hexagon hole 2, the contact area between the generated copper foil and the titanium plate 1 can be reduced, which is convenient for foil stripping. In addition, it is worth noting that the center line 21 of one of the top corners 22 of the regular hexagon hole 2 is perpendicular to the wide side 11 of the titanium plate 1, that is, the top corner 22 of the regular hexagon hole 2 is opposite to the frame of the titanium plate 1. Such arrangement makes it easy to start from the top corner of the regular hexagon hole 2 during the foil stripping, which is labor-saving and not easy to stick the foil.

[0025] S4, polishing the surface of the titanium plate 1 to remove irregular structures generated on the surface of the titanium plate 1 by laser, and cleaning the surface of the titanium plate 1 with pure water and alcohol; The titanium plate 1 after punching is polished to remove irregular structures left on the surface of the titanium plate 1 by laser punching. Specifically, the surface of the titanium plate 1 is polished to a roughness Ra<0.3 μm and Rz<3.0 μm, where Rz is the maximum height of the profile, and then the surface of the titanium plate 1 is cleaned with pure water or alcohol, finally obtaining a clean titanium plate 1.

[0026] S5, configuring copper sulfate electrolyte and adding appropriate amount of brightener, wetting agent and high resistance agent into the electrolyte; Specifically, the copper ion concentration in the copper sulfate electrolyte is 80-100 g / L, the sulfuric acid concentration is 100-120 g / L, the chloride ion concentration is 20-30 ppm, and the electrolyte temperature is 50-60℃; then appropriate amount of brightener, wetting agent and high resistance agent are added into the electrolyte; further, the brightener is one or more of polydithiodipropyl sulfonate sodium, 3-mercapto-1-propane sulfonic acid sodium, N,N-dimethyl dithiocarbamic acid propane sulfonic acid sodium and isothiourea propyl sulfonic acid inner salt; the wetting agent is one or more of polyethylene glycol, collagen, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, gelatin, fatty alcohol polyoxyethylene ether sulfonated succinic acid monoester disodium; the high resistance agent is one or more of tetrahydrothiazole thione, polyethyleneimine, 2-mercaptobenzimidazole and ethylene thiourea.

[0027] S6, pouring the electrolyte into the electrolytic tank, and placing the carbon plate and the titanium plate 1 in the S4 step into the electrolytic tank and fixing them; The electrolyte and the brightener, wetting agent, high resistance agent mixed solution are poured into the electrolytic cell, the amount of the brightener, wetting agent and high resistance agent is controlled, so that the concentration of the brightener, the wetting agent and the high resistance agent is respectively: the brightener 2-10ppm, the wetting agent 3-15ppm, the high resistance agent 0.5-3ppm, then the mixed solution is kept constant temperature by heating control through the electrolytic cell, then the clean titanium plate 1 and the carbon plate are put into the electrolyte mixed solution, and are fixed, so that the pole distance of the titanium plate 1 and the carbon plate is between 5-30mm.

[0028] S7, the titanium plate 1 is used as a cathode, and the carbon plate is used as an anode, and electrolytic foil is generated; after the electrolytic foil is generated, the copper foil is peeled off from the surface of the titanium plate 1, and a porous copper foil with a regular hexagonal hole 2 is obtained; It should be noted that the current during electrolytic foil generation is ensured to be between 20-25A, and the electroplating time is between 55-60s, so that the copper foil with a thickness of 6-8μm can be generated on one side of the titanium plate 1; after the electrolytic foil generation is completed, the copper foil is peeled off from the surface of the titanium plate 1, so that the porous copper foil with the regular hexagonal hole 2 is obtained.

[0029] As a preferred mode, before the laser device punches, the wavelength of the laser can be set to 300-350nm, the laser spot size is set to 10-15μm, and the punching time is set to 1-2min, so that the laser device punches the regular hexagonal hole 2 with a hole depth of 10-20μm in a more energy-saving and time-saving manner, and the punching efficiency is improved.

[0030] In some embodiments, before the titanium plate 1 is polished in the S4 step, the titanium plate 1 can be coated with a shielding material to shield the regular hexagonal hole inside the titanium plate 1, reduce the generation of copper foil in the hole during the generation of copper foil, and cause difficulty in foil peeling; wherein the shielding material can be an insulating acid-resistant epoxy resin.

[0031] Embodiment 1; The method for preparing the porous copper foil with a regular hexagonal hole array provided by the first embodiment of the present application comprises the following steps: S1, a titanium plate with a thickness of 5mm, a width of 6cm and a length of 15cm is selected. The titanium plate is polished with 1000 mesh sandpaper and then polished with 1200 mesh sandpaper. After polishing, the roughness of the titanium plate is Ra = 0.244μm and Rz = 1.659μm.

[0032] S2, CAD software is used to draw a laser punching drawing, wherein the edge center distance of the regular hexagonal hole is 40μm, and the distance between the regular hexagonal holes is 120μm.

[0033] S3, import the drawing into the laser equipment, and use the laser equipment to perform laser drilling on the titanium plate, wherein the laser wavelength is set to 340 nm, the laser spot size is 10 μm, the drilling time of each hole is 1 min, and the drilling depth is 20 μm. The laser wavelength for fine-tuning the right hexagonal vertex is 340 nm, and the laser light plate size is 8 μm. After the titanium plate is laser drilled, as shown in Figure 1 , the drilled right hexagonal hole array is as shown in Figure 2 , the super-depth 3D microscope image of the right hexagonal hole array region; as shown in Figure 3 , the super-depth 3D microscope image of the right hexagonal hole array region is as shown in Figure 4

[0034] S4, polish the drilled titanium plate with 1200 mesh sandpaper, and the roughness of the polished titanium plate is Ra = 0.233 μm and Rz = 1.409 μm, then wash the titanium plate with pure water and alcohol to obtain a clean titanium plate.

[0035] S5, use copper sulfate pentahydrate, 98% concentrated sulfuric acid, and NaCl to configure a pure copper sulfate electrolyte, and use a water bath device for heating and stirring. The copper sulfate electrolyte has a copper ion concentration of 90 g / L, a sulfuric acid concentration of 110 g / L, a chloride ion concentration of 25 ppm, and an electrolyte temperature of 55°C.

[0036] After the copper sulfate is completely dissolved, a brightener, a wetting agent, and a high-resistance agent are added to the electrolyte. The added brightener is one of polydithiopropanesulfonic acid sodium, 3-mercapto-1-propanesulfonic acid sodium, N, N-dimethyl dithiocarbamic acid propane sulfonic acid sodium, and isothiourea propane sulfonic acid inner salt. The wetting agent is several of polyethylene glycol, collagen, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, gelatin, and fatty alcohol polyoxyethylene ether sulfosuccinic acid monoester disodium. The high-resistance agent is one of tetrahydrothiazole thione, polyethyleneimine, 2-mercaptobenzimidazole, and ethylene thiourea. After the additives are added, the electrolyte is stirred uniformly.

[0037] The concentration of the added brightener is 6 ppm, the concentration of the wetting agent is 10 ppm, and the concentration of the high-resistance agent is 1.5 ppm.

[0038] S6, pour the configured electrolyte into an electrolysis tank, and install a carbon plate and a titanium plate drilled by laser.

[0039] S7, use the titanium plate as a cathode and the carbon plate as an anode to perform electrolytic foil growth; control the foil growth current to be 25 A, the electroplating time to be 60 s, and the copper foil thickness to be 8 μm; after the foil growth is completed, the copper foil is peeled off from the surface of the titanium plate to obtain a porous copper foil with a right hexagonal hole array, as shown in Figure 5 ​As shown, a 3D microscope image of a porous copper foil with a regular hexagonal aperture array, exhibiting ultra-depth of field; Figure 6 The image shown is a magnified 3D microscope image of a portion of the copper foil, displaying a super depth of field.

[0040] Comparative Example 2; The method for preparing porous copper foil with a regular hexagonal hole array provided in the second embodiment of the present invention differs from that in Embodiment 1 in that: In step 2, a drilling drawing is created using CAD, where the controlled shape is circular. In contrast, in Comparative Example 2, the surface roughness of the titanium plate after grinding and polishing in step S1 is Ra=0.252μm and Rz=1.737μm. Drilling is then performed on the titanium plate. Figure 7 The image shown is a magnified 3D microscope image of the circular hole area on the titanium plate, with super depth of field.

[0041] After polishing in step S4, the surface roughness of the titanium plate is Ra=0.236μm and Rz=1.578μm; other steps are the same as in Example 1 and will not be repeated here; after the electrolytic foil is formed, the copper foil is peeled off from the surface of the titanium plate to obtain a porous copper foil with circular holes, such as... Figure 8 The image shown is a magnified 3D microscope image of a porous copper foil with a circular hole, displaying a super depth of field.

[0042] The comparison shows that when drilling circular holes in a titanium plate, the copper foil at the edges of the holes tends to stick to the titanium plate during peeling, preventing the porous copper foil from maintaining its original shape. In contrast, titanium plates with hexagonal holes allow for easier peeling of the copper foil, thus preserving the integrity of the porous copper foil.

[0043] Comparative Example 3; The method for preparing porous copper foil with a regular hexagonal hole array provided in the third embodiment of the present invention differs from that in Embodiment 1 in that: After grinding and polishing the titanium plate in step S1, the surface roughness is Ra=0.250μm and Rz=1.713μm; In step S3, holes were drilled in the titanium plate, but no further finishing treatment was performed on the titanium plate; for example... Figure 9 The image shown is a magnified 3D microscope image of the hexagonal hole area on the titanium plate, with super depth of field. After polishing the titanium plate in step S4, the surface roughness of the titanium plate is Ra=0.245μm and Rz=1.599μm. Other steps are the same as in Example 1 and will not be repeated here. After the electrolytic foil formation is completed, the copper foil is peeled off from the surface of the titanium plate to obtain a porous copper foil with regular hexagonal shapes, such as... Figure 10 The image shown is a magnified 3D microscope image of a portion of a hexagonal porous copper foil, with super depth of field.

[0044] It can be seen that, without the sharpening treatment of the top corners of the regular hexagonal holes, the copper foil of the hole edge part is easy to stick to the titanium plate when the multi-hole copper foil is stripped, which leads to that the multi-hole copper foil cannot keep the original morphology well. The sharpening treatment of the top corners of the regular hexagonal holes can reduce the sticking phenomenon of the hole edge part and the titanium plate, and further make the copper foil after stripping have better integrity and improve the product yield.

[0045] In summary, the method for preparing the multi-hole copper foil with regular polygon hole array in the above-mentioned embodiments of the present application can reduce the sticking phenomenon of the hole edge part of the regular polygon hole of the copper foil and the titanium plate when the copper foil is stripped after electrolytic foil growth, thereby ensuring the integrity of the copper foil.

[0046] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0047] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the present application. It should be noted that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for preparing a porous copper foil with a regular polygonal hole array, characterized in that, The preparation method includes the following steps: S1, Polish the surface of the titanium plate to a matte finish; S2, using computer-aided drawing to create a hole pattern, wherein the shape of the hole in the pattern is drawn as a regular polygon, and the center-to-side distance of the hole and the spacing between adjacent holes are determined according to the porosity. S3. According to the drawing, a hole is made on the polished side of the titanium plate using a laser device. The depth of the hole is controlled by the laser wavelength and the laser processing time. The apex corner of the regular polygonal hole is further refined by the laser device. S4, polish the surface of the titanium plate to remove the irregular structure generated by the laser on the surface of the titanium plate, and clean the surface of the titanium plate with pure water and alcohol. S5, prepare copper sulfate electrolyte, and add brightener, wetting agent and high resistance agent to the electrolyte; S6, pour the electrolyte into the electrolytic cell, and place the carbon plate and the titanium plate from step S4 into the electrolytic cell, and fix the carbon plate and the titanium plate. S7. Electrolytic foil is produced by using a titanium plate as the cathode and a carbon plate as the anode. After the foil production is completed, the copper foil is peeled off from the surface of the titanium plate to obtain a porous copper foil with regular polygonal holes.

2. The method for preparing porous copper foil with a regular polygonal hole array according to claim 1, characterized in that, In step S1, the thickness of the titanium plate is 3-10 mm, and the surface roughness Ra of the polished titanium plate is <0.3 μm.

3. The method for preparing porous copper foil with a regular polygonal hole array according to claim 1, characterized in that, In step S2, the holes of the regular polygon are regular hexagons, the center-to-side distance of the regular hexagonal holes is 20-150mm, the spacing between adjacent regular hexagonal holes is 40-300μm, and an array of several regular hexagonal holes is formed.

4. The method for preparing porous copper foil with a regular polygonal hole array according to claim 1, characterized in that, In step S3, the laser wavelength is 200-800nm, the laser spot size is 6-30μm, the drilling time is 0.5-5min, and the drilling depth is 5-50μm.

5. The method for preparing porous copper foil with a regular polygonal hole array according to claim 4, characterized in that, The laser wavelength is 300-350nm, the laser spot size is 10-15μm, the drilling time is 1-2min, and the drilling depth is 10-20μm.

6. The method for preparing porous copper foil with a regular polygonal hole array according to claim 1, characterized in that, The apex corner of the regular polygonal hole is further refined using a laser device. The processing steps include setting the wavelength of the laser device to 200-350nm and the laser spot size to 6-15μm, and then sharpening the apex corner of the regular polygonal hole.

7. The method for preparing porous copper foil with a regular polygonal hole array according to claim 1, characterized in that, In step S4, the surface roughness of the titanium plate is Ra<0.3μm and Rz<3.0μm, where Rz is the maximum height of the profile.

8. The method for preparing porous copper foil with a regular polygonal hole array according to claim 1, characterized in that, In step S5, the copper ion concentration in the copper sulfate electrolyte is 80-100 g / L, the sulfuric acid concentration is 100-120 g / L, the chloride ion concentration is 20-30 ppm, and the electrolyte temperature is 50-60℃.

9. The method for preparing porous copper foil with a regular polygonal hole array according to claim 1, characterized in that, In step S5, the brightener is one or more of sodium dithiodipropanesulfonate, sodium 3-mercapto-1-propanesulfonate, sodium N,N-dimethyldithiocarbamate propanesulfonate, and isothiourea propanesulfonate inner salt; the wetting agent is one or more of polyethylene glycol, collagen, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, gelatin, and disodium fatty alcohol polyoxyethylene ether sulfonated succinate; the high-resistance agent is one or more of tetrahydrothiazolylthione, polyethyleneimine, 2-mercaptobenzimidazole, and ethylene thiourea. The concentrations of the brightener, the wetting agent, and the high-resistance agent are respectively: brightener 2-10 ppm, wetting agent 3-15 ppm, and high-resistance agent 0.5-3 ppm.

10. The method for preparing porous copper foil with a regular polygonal hole array according to claim 1, characterized in that, In step S7, the current during electrolysis of the copper foil is 20-25A, the electroplating time is 55-60s, and the copper foil thickness is 6-8μm.

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