Printing ink for coating side edge of battery piece and printing process applying printing ink

Abstract

The invention discloses printing ink for coating the side edge of a battery piece and a printing process applying the printing ink, and the printing ink for coating the side edge of the battery piece comprises the following components in parts by weight: 35-55 parts of carboxylated resin; 0.05 to 5 parts of a thermosetting hardener; 0.1 to 5 parts of an auxiliary agent; 40-60 parts of a solvent; 0.1-5 parts of a pigment; the viscosity of the printing ink ranges from 1000 cp to 3000 cp. In the copper electroplating process, the ink can resist acid etching of electroplating liquid and does not fall off, the phenomenon of copper growth at the edge of a battery piece in the electroplating process is inhibited, the problem of short circuit of the battery piece caused by a winding plating phenomenon is solved, and the efficiency of the battery piece is effectively improved; meanwhile, the photosensitive ink layer has the characteristic of being easily removed by alkali liquor, after copper electroplating is completed, the photosensitive ink layer on the front face or the back face of the battery piece is etched and removed by the alkali liquor at the same time, the step of removing the ink coating does not need to be additionally added, and the functional characteristics of subsequent battery piece elements are not affected.

Description

Technical Field

[0001] The present invention relates to the field of battery cell manufacturing, and particularly to an ink for coating the sides of battery cells and a preparation process thereof. Background Art

[0002] During the preparation of battery cells, after the battery cells are cleaned and textured, the preparation of the base layer of the battery cells starts with PECVD. That is, an intrinsic amorphous silicon layer with a thickness of 5 - 10 nm is deposited as a passivation layer. At the same time, on the outer side of the intrinsic amorphous silicon layer, a boron-doped P-type microcrystalline silicon layer is deposited on the back surface and a phosphorus-doped N-type microcrystalline silicon layer is deposited on the front surface respectively. At this time, the sides of the battery cells will also be sequentially deposited and coated. Immediately afterwards, a composite transport layer is prepared by a vacuum deposition process such as PVD or RPD. The characteristic of this process is that it will deposit not only on the front and back surfaces of the battery cells, but also on the sides of the battery cells, which is the so-called overplating phenomenon. Due to the existence of the overplating phenomenon, the problem of short circuit of the battery cells will occur. Summary of the Invention

[0003] To overcome the above disadvantages, the purpose of the present invention is to provide an ink for coating the sides of battery cells to inhibit the overplating phenomenon at the edges of battery cells during electroplating.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: an ink for coating the sides of battery cells, comprising the following components in parts by weight: 35 - 55 parts of carboxylated resin; 0.05 - 5 parts of thermosetting hardener; 0.1 - 5 parts of auxiliary agent; 40 - 60 parts of solvent; 0.1 - 5 parts of colorant; The viscosity of the ink is 1000 - 3000 cp.

[0005] The present invention prepares an ink specifically for coating the sides of battery cells by using carboxylated resin, thermosetting hardener, auxiliary agent, solvent and colorant, and solves the problem of overplating on the sides of battery cells. And by controlling the proportion of each component, the ink can well coat the sides of battery cells within a certain viscosity range. In addition, during the electroplating of copper, it can withstand the acid etching of the electroplating solution without falling off, and after the electroplating of copper is completed, it is etched and removed by an alkaline solution simultaneously with the photosensitive ink layer on the front or back surface of the battery cell.

[0006] Further, it comprises the following components in parts by weight: 43 - 47 parts of carboxylated resin; 47 - 51 parts of solvent; 1 - 3 parts of thermosetting hardener.

[0007] Exemplarily, the carboxylated resin is in the range of 43 parts, 44 parts, 45 parts, 46 parts, 47 parts or any range composed of any two of them; the solvent is in the range of 47 parts, 48 parts, 49 parts, 50 parts, 51 parts or any range composed of any two of them; the thermosetting hardener is in the range of 1 part, 2 parts, 3 parts or any range composed of any two of them. By limiting the amounts of the carboxylated resin, solvent and thermosetting hardener, the viscosity of the prepared ink is between 1500 and 3000 cp, ensuring that during the process of coating the sides of the battery cells, there will be neither ink overflow due to low viscosity nor wire breakage due to too high viscosity.

[0008] Further, the carboxylated resin is selected from one or more of carboxylated polyacrylic resin, carboxylated polyurethane, carboxylated polyimide resin, and carboxylated epoxy resin.

[0009] Further, the carboxylated polyacrylic resin is formed by thermal polymerization of acrylic monomers.

[0010] Further, the carboxylated epoxy resin is selected from one or more of carboxylic acid-modified bisphenol A epoxy resin, carboxylic acid-modified bisphenol F epoxy resin, carboxylic acid-modified phenolic epoxy resin, and carboxylic acid-modified o-cresol novolac epoxy resin.

[0011] Further, the average molecular weight range of the carboxylated resin is 1000 - 50000, and the solid acid value range is 50 - 150 mgKOH / g.

[0012] Further, the solvent is selected from one or more mixtures of methanol, ethanol, n-propanol, isopropanol, ethylene glycol, propylene glycol, acetone, methyl ethyl ketone, cyclohexanone, N-methyl-2-pyrrolidone, toluene, xylene, triethanol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate benzoguanamine; Further, the auxiliary agent includes a component: polyether-modified polydimethylsiloxane.

[0013] Further, the auxiliary agent is selected from one or more mixtures of BYK-300, BYK-301, BYK-302, BYK-306, BYK-310, BYK-314, BYK-315, BYK-320, BYK-322, BYK-323, BYK-326, BYK-327, BYK-330, BYK-331, BYK-332, BYK-333, BYK-337, BYK-342, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-350, BYK-352, BYK-354, BYK-355, BYK-356, BYK-359, BYK-370, BYK-377, BYK-378.

[0014] Further, the thermosetting hardener is selected from at least one of modified epoxy resins and their derivatives, modified amino resins and their derivatives, and modified isocyanates and their derivatives.

[0015] Further, the structural formula of the modified epoxy resin is , where R is selected from any one of straight-chain alkyl groups, cyclic aliphatic groups, and aromatic groups. Exemplarily, R is a cyclohexyl group, a n-pentyl group, or a phenyl group.

[0016] Further, the structural formula of the modified isocyanate is , where R' is selected from any one of straight-chain alkyl groups, cyclic aliphatic groups, and aromatic groups. Exemplarily, R' is a cyclohexyl group, a n-alkyl group, or a phenyl group.

[0017] Further, the structural formula of the modified amino resin is .

[0018] The thermosetting hardener contains epoxy groups, isocyanate groups, or amino groups. During the curing process, the hardener reacts with the resin molecules to form an infusible three-dimensional network structure. This structure imparts high strength, high hardness, and good chemical resistance to the material.

[0019] Further, the molecular weight range of the thermosetting hardener is between 100 and 3000, and the suitable reaction temperature is between 80 and 100 degrees.

[0020] Further, the solid content of the ink is 40 - 60%.

[0021] A printing process using the ink as described above includes the following steps: S1. Coating the ink on the side of the battery cell by roll coating to form an ink coating on the side of the battery cell; covering the side of the battery cell through the ink coating, so that during the later copper plating process, copper plating cannot be deposited on the side of the battery cell.

[0022] S2. Dry the ink coating by hot air or infrared rays; S3. Perform copper electroplating on the upper side and / or lower side of the battery cell to form electroplated copper on the upper side and / or lower side of the battery cell; S4. Immerse the ink coating in an alkali to remove the ink coating from the side of the battery cell.

[0023] Further, in S1, the thickness of the ink coating is 10 - 30 microns.

[0024] Further, in S2, the temperature for drying the ink coating is 100 - 120 °C, and the time is 1 - 5 minutes.

[0025] Further, in S3, the thickness of the electroplated copper is 6 - 12 microns.

[0026] Further, in S4, the alkali solution is a 3 - 5% potassium hydroxide aqueous solution, the immersion temperature is 40 - 50 °C, and the time is 1 - 10 minutes.

[0027] The beneficial effects of the present invention are as follows: 1) By using carboxylated resin, thermosetting hardener, additives, solvent and colorant, the present invention prepares an ink specifically used for coating the side of the battery cell, solving the problem of side plating of the battery cell. And by controlling the proportion of each component, the ink can well coat the side of the battery cell by roll coating printing within a certain viscosity range.

[0028] 2) During the copper electroplating process, the ink of the present invention can withstand acid etching of the electroplating solution without falling off, inhibiting the copper growth phenomenon at the edge of the battery cell during electroplating, solving the problem of battery cell short - circuit caused by side plating phenomenon, and effectively improving the efficiency of the battery cell; at the same time, it has the characteristic of being easily removed by alkali solution. After the copper electroplating is completed, it is etched and removed by the alkali solution together with the photosensitive ink layer on the front or back of the battery cell, without the need to add an extra step to remove the ink coating, and does not affect the functional characteristics of subsequent battery cell components. Description of the Drawings

[0029] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0031] Figure 1 Schematic diagram of coating an ink layer on the side of a battery cell according to the present invention; Figure 2 Schematic diagram of electroplating a copper layer on a battery cell according to the present invention; Figure 3 Schematic diagram of removing the ink layer and the mask layer according to the present invention; Figure 4 SEM images of the ink layers of Examples 1 - 7 and Comparative Examples 1 - 2 before electroplating copper according to the present invention; Figure 5 SEM images of the ink layers of Examples 1 - 6 and Comparative Examples 1 - 2 after electroplating copper according to the present invention.

[0032] Among them, 1, battery cell; 2, electroplated copper layer; 3, ink layer; 4, mask layer. Detailed implementation manners

[0033] To make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the following provides a detailed description of the specific implementation manners of the present invention. Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0034] Unless otherwise indicated in the operating examples or otherwise stated, all numbers representing the amounts of components, physical and chemical properties, etc. in the specification and claims are understood to be adjusted by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters listed in the above - mentioned specification and appended claims are approximate values, and those skilled in the art can, using the teachings disclosed herein, seek to obtain the desired characteristics and appropriately change these approximate values. The use of numerical ranges expressed with endpoints includes all numbers within that range and any sub - ranges within that range. For example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc.

[0035] The applicant found that due to the existence of the problem of copper plating around during the electroplating copper process, it will cause the problem of short - circuit of the battery cell and affect the performance of the battery cell. And during the process of screen - coating and printing a mask layer on the front or back of the battery cell, due to factors such as viscosity and uniformity of the ink of the mask layer, the side of the battery cell cannot be well coated.

[0036] An embodiment of the present invention provides an ink specifically for coating the side of a battery cell to solve the above problems. Specifically, the ink includes the following components in parts by weight: 35 - 55 parts of carboxylated resin; 0.05 - 5 parts of thermosetting hardener; Auxiliary agent: 0.1 to 5 parts; Solvent: 40 to 60 parts; Colorant: 0.1 to 5; The viscosity of the ink is 1000 to 3000 cp.

[0037] In some embodiments, it includes components in the following weight parts: carboxylated resin: 43 to 47 parts; solvent: 47 to 51 parts; thermosetting hardener: 1 to 3 parts.

[0038] In some embodiments, the carboxylated resin is selected from one or more of carboxylated polyacrylic resin, carboxylated polyurethane, carboxylated polyimide resin, and carboxylated epoxy resin.

[0039] In some embodiments, the carboxylated polyacrylic resin is formed by thermal polymerization of acrylic monomers.

[0040] In some embodiments, the carboxylated epoxy resin is selected from one or more of carboxylic acid-modified bisphenol A epoxy resin, carboxylic acid-modified bisphenol F epoxy resin, carboxylic acid-modified phenolic epoxy resin, and carboxylic acid-modified o-cresol novolac epoxy resin.

[0041] In some embodiments, the average molecular weight range of the carboxylated resin is 1000 to 50000, and the solid acid value range is 50 to 150 mgKOH / g.

[0042] In some embodiments, the solvent is selected from one or more mixtures of methanol, ethanol, n-propanol, isopropanol, ethylene glycol, propylene glycol, acetone, methyl ethyl ketone, cyclohexanone, N-methyl-2-pyrrolidone, toluene, xylene, triethanol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, and benzoguanamine.

[0043] In some embodiments, the auxiliary agent includes components: polyether-modified polydimethylsiloxane.

[0044] In some embodiments, the auxiliary agent is selected from one or more mixtures of BYK-300, BYK-301, BYK-302, BYK-306, BYK-310, BYK-314, BYK-315, BYK-320, BYK-322, BYK-323, BYK-326, BYK-327, BYK-330, BYK-331, BYK-332, BYK-333, BYK-337, BYK-342, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-350, BYK-352, BYK-354, BYK-355, BYK-356, BYK-359, BYK-370, BYK-377, BYK-378.

[0045] In some embodiments, the thermosetting hardener is selected from at least one of modified epoxy resins and their derivatives, modified amino resins and their derivatives, and modified isocyanates and their derivatives; In some embodiments, the structural formula of the modified epoxy resin is , and R is selected from any one of linear alkyl groups, cyclic aliphatic groups, and aromatic groups; In some embodiments, the structural formula of the modified isocyanate is , and R' is selected from any one of linear alkyl groups, cyclic aliphatic groups, and aromatic groups; In some embodiments, the structural formula of the modified amino resin is .

[0046] In some embodiments, the molecular weight range of the thermosetting hardener is between 100 and 3000, and the suitable reaction temperature is between 80 and 100 degrees; In some embodiments, the solid content of the ink is 40-60%.

[0047] A printing process using the ink as described above includes the following steps: S1, as shown in the attached Figure 1 , the ink is coated on the side of the battery cell 1 by roll coating to form an ink coating 3 on the side of the battery cell 1. Among them, before the ink coating 3 is coated on the side of the battery cell 1, mask layers 4 have been provided on the front and back sides of the battery cell 1, and the openings of the mask layers are used for electroplating copper.

[0048] In some embodiments, the thickness of the ink coating is 10-30 microns. It has been found that when the thickness of the ink coating of the present invention is 10-30 microns, it has good coverage of the side of the battery cell and is resistant to acid etching by the electroplating solution.

[0049] S2. The ink coating is dried by hot air or infrared rays.

[0050] In some embodiments, the temperature of the dried ink coating is 100 to 120 degrees, and the time is 1 to 5 minutes.

[0051] S3. Refer to the appendix Figure 2 As shown, copper electroplating is performed on the upper side and / or the lower side of the battery cell 1, and an electroplated copper layer 2 is formed on the upper side and / or the lower side of the battery cell.

[0052] In some embodiments, the thickness of the electroplated copper layer 2 is 6 to 12 micrometers; S4. Refer to the appendix Figure 3 As shown, the ink coating 3 is soaked with an alkali to remove the ink coating 3 from the side of the battery cell.

[0053] In some embodiments, in S4, the alkali solution is a 3 to 5% aqueous potassium hydroxide solution, the soaking temperature is 40 to 50 °C, and the time is 1 to 10 minutes. During the process of soaking the ink coating 3 with the alkali solution, the mask layer 3 can be removed synchronously.

[0054] Embodiment The following embodiments more specifically describe the content disclosed in the present invention. These embodiments are only for illustrative purposes, because various modifications and changes within the scope of the present invention are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and all instruments used in the embodiments are commercially available.

[0055] Embodiment 1 Preparation of ink: Mix 40 parts of carboxylated resin, 56 parts of solvent (triethanol monoethyl ether), 1 part of additive (BYK-378), 1 part of thermosetting agent, and 2 parts of colorant, and stir with a disperser at 600 rpm for 20 minutes. Then add 2 parts of colorant and stir with a disperser at 600 rpm for 60 minutes. The stirred product is allowed to stand for 24 hours before use.

[0056] Among them, the main component of the carboxylated resin is a mixture of carboxylated polyacrylate resin and carboxylated epoxy resin, purchased from Kaixincheng Co., Ltd., and the product model is SR237.

[0057] The main component of the additive is polyether-modified polydimethylsiloxane, purchased from BYK Chemie GmbH (Germany), and the product model is BYK-378; The main component of the thermosetting agent is an amino resin derivative, purchased from Changchun Chemical (Jiangsu) Co., Ltd., and the product model is MR-603.

[0058] The main component of the colorant is carbon black, purchased from Cabot Corporation, and the product model is 710.

[0059] Edge coating of the solar cell: The ink is applied to the edges of the solar cell by roll coating to form an ink coating with a thickness of 20 microns on the edges of the solar cell; the ink coating is dried by hot air or infrared rays, and the drying temperature of the ink coating is 110 °C and the time is 3 minutes; the edge coating situation of the ink coating on the solar cell is observed with a microscope, see Figure a in the appendix. Figure 4 Copper electroplating is carried out on the upper side and / or lower side of the solar cell to form an electroplated copper layer with a thickness of 9 microns on the upper side and / or lower side of the solar cell; the situation of whether the ink coating peels off is observed with a microscope, see Figure a2 in the appendix. Figure 5 The ink coating is soaked with alkali to remove the ink coating from the edges of the solar cell. The alkali solution is a 4% potassium hydroxide aqueous solution, the soaking temperature is 45 °C, and the soaking time is 3 minutes.

[0060] Example 2 Example 2 is basically the same as Example 1, and the main difference lies in the different amounts of solvent and thermosetting hardener added. Specifically, in Example 2, 55 parts of solvent and 2 parts of thermosetting hardener are added.

[0061] Example 3 Example 3 is basically the same as Example 1, and the main difference lies in the different amounts of solvent and thermosetting hardener added. Specifically, in Example 3, 54 parts of solvent and 3 parts of thermosetting hardener are added.

[0062] Example 4 Example 4 is basically the same as Example 1, and the main difference lies in the different amounts of resin, solvent and thermosetting hardener added. Specifically, in Example 4, 43 parts of resin, 51 parts of solvent and 3 parts of thermosetting hardener are added.

[0063] Example 5 Example 5 is basically the same as Example 1, and the main difference lies in the different amounts of resin, solvent and thermosetting hardener added. Specifically, in Example 5, 45 parts of resin, 49 parts of solvent and 3 parts of thermosetting hardener are added.

[0064] Example 6 Example 6 is basically the same as Example 1, and the main difference lies in the different amounts of resin, solvent and thermosetting hardener added. Specifically, in Example 6, 47 parts of resin, 47 parts of solvent and 3 parts of thermosetting hardener are added.

[0065] Example 7 Example 7 is basically the same as Example 1, and the main difference lies in the different amounts of resin, solvent and thermosetting hardener added. Specifically, in Example 7, 50 parts of resin, 44 parts of solvent and 3 parts of thermosetting hardener are added.

[0066] Comparative Example 1 Comparative Example 1 is basically the same as Example 1, and the main difference lies in the different amounts of resin, solvent and thermosetting hardener added. Specifically, in Comparative Example 1, 45 parts of resin, 52 parts of solvent and 0 part of thermosetting hardener are added.

[0067] Comparative Example 2 Comparative Example 2 is basically the same as Comparative Example 1, and the main difference is that during the process of coating the battery chip with the ink, the temperature for drying the ink coating is 120 degrees.

[0068] Experimental Example 1 The viscosity of the inks prepared in Examples 1-7 and Comparative Examples 1-2 was tested, and after the ink was coated on the side of the battery, the shape of the ink coating was observed through a microscope. See Appendix Figure 4 In Appendix Figure 4 , in Appendix

[0069] , Figure a is the SEM image of the side coating of the battery chip with the ink prepared in Example 1; Figure b is the SEM image of the side coating of the battery chip with the ink prepared in Example 2; Figure c is the SEM image of the side coating of the battery chip with the ink prepared in Example 3; Figure d is the SEM image of the side coating of the battery chip with the ink prepared in Example 4; Figure e is the SEM image of the side coating of the battery chip with the ink prepared in Example 5; Figure f is the SEM image of the side coating of the battery chip with the ink prepared in Example 6; Figure g is the SEM image of the side coating of the battery chip with the ink prepared in Example 7; Figure h is the SEM image of the side coating of the battery chip with the ink prepared in Comparative Example 1; Figure i is the SEM image of the side coating of the battery chip with the ink prepared in Comparative Example 2. Figure 5 Figure 5 After electroplating copper, the microscope was used again to observe whether the ink coating peeled off. See Appendix

[0070] Table 1

[0071] Figure 4 See Table 1 and Figure 4As shown, the inks prepared in Examples 4-6 and Comparative Examples 1-2 have the best coating on the sides of the battery, and there is no ink overflow or break point. The possible reason is that the viscosity of the inks prepared in Examples 4-6 and Comparative Examples 1-2 is between 1000-3000 cp. There will be no ink overflow due to low viscosity, nor wire breakage due to too high viscosity. Therefore, from the side coating phenomena of Examples 1-7 and Comparative Examples 1-2 on the battery chips, it can be seen that the viscosity difference leads to the edge coating difference. When the viscosity is controlled between 1000-3000 cp, the coating effect on the sides of the battery is the best.

[0072] See Table 1 and Figure 5 As shown, after electroplating copper, the inks in Example 1, Example 2, Comparative Example 1, and Comparative Example 2 cannot withstand the acid etching of the electroplating solution and partially fall off, which will cause copper winding phenomenon on the sides where the inks fall off, affecting the performance of the battery chips. The sides of the battery chips in Examples 3-6 are coated intact without falling off. Therefore, adding thermosetting hardeners can improve the electroplating resistance of the inks. And from Examples 1-3, it can be seen that the higher the proportion of the thermosetting hardener added, the better its electroplating resistance.

[0073] From the observed phenomena in Comparative Example 1 and Comparative Example 2: When the drying temperature is raised to 120 °C and the drying time is maintained at 3 minutes, after electroplating copper, the ink coating still cannot withstand the acid etching of the electroplating solution and falls off.

[0074] Experimental Example 2 Perform performance tests on the battery chips prepared in Examples 4-6 and Comparative Examples 1-2. The test results are shown in Table 2.

[0075]

[0076] From the battery performance data tested in Table 2, it can be seen that in Examples 4-6, due to the good coating of the inks on the sides of the battery chips, better battery chip efficiency is obtained, which can effectively form high-performance battery chips and improve electrical properties such as Rsh. Therefore, the ink prepared by the formula of the present invention can well coat the sides of the battery chips and effectively improve the battery chip efficiency.

[0077] The present invention uses the above examples to illustrate the detailed process equipment and process flow of the present invention. However, the present invention is not limited to the above detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, equivalent replacement of each raw material of the product of the present invention, structural form change, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0078] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it. It should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. An ink for coating the side of a battery cell, characterized in that: The composition comprises the following components in parts by weight: 35-55 parts of carboxylated resin; Thermosetting hardener 0.05~5 parts; 0.1 to 5 parts of additives; 40-60 parts of solvent; Pigment 0.1~5; The viscosity of the ink is 1000~3000cp.

2. The ink for coating the side of a battery cell according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 43-47 parts of carboxylated resin; 47-51 parts of solvent; and 1-3 parts of thermosetting hardener.

3. The ink for coating the side of a battery cell according to claim 1, characterized in that: The carboxylated resin is selected from one or more of carboxylated polyacrylic resin, carboxylated polyurethane, carboxylated polyimide resin, and carboxylated epoxy resin; Carboxylated polyacrylic resin is made by thermal polymerization of acrylic monomers; The carboxylated epoxy resin is selected from one or more of carboxylic acid-modified bisphenol A epoxy resin, carboxylic acid-modified bisphenol F epoxy resin, carboxylic acid-modified novolac epoxy resin, and carboxylic acid-modified o-cresol epoxy resin.

4. The ink for coating the side of a battery cell according to claim 1, characterized in that: The average molecular weight of the carboxylated resin ranges from 1000 to 50000, and the solid acid value ranges from 50 to 150 mgKOH / g.

5. The ink for coating the side of a battery cell according to claim 1, characterized in that: The solvent is selected from one or more mixtures of methanol, ethanol, n-propanol, isopropanol, ethylene glycol, propylene glycol, acetone, methyl ethyl ketone, cyclohexanone, N-methyl-2-pyrrolidone, toluene, xylene, triethanol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, benzoguanamine; The auxiliary agent comprises the component: polyether-modified polydimethylsiloxane.

6. The ink for coating the side of a battery cell according to claim 1, characterized in that: The auxiliary agent is selected from BYK-300, BYK-301, BYK-302, BYK-306, BYK-310, BYK-314, BYK-315, BYK-3 20, BYK-322, BYK-323, BYK-326, BYK-327, BYK-330, BYK-331, BYK-332, BYK-333, B One or more mixtures of YK-337, BYK-342, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-350, BYK-352, BYK-354, BYK-355, BYK-356, BYK-359, BYK-370, BYK-377, BYK-378.

7. The ink for coating the side of a battery cell according to claim 1, characterized in that: The thermosetting hardener is selected from at least one of modified epoxy resin and its derivatives, modified amino resin and its derivatives, modified isocyanate and its derivatives; The structural formula of the modified epoxy resin is , R is selected from any one of a straight-chain alkyl group, a cyclic aliphatic group, and an aromatic group; The structural formula of modified isocyanate is , R ， Any one selected from a straight-chain alkyl group, a cyclic aliphatic group, and an aromatic group; The structural formula of the modified amino resin is .

8. The ink for coating the side of a battery cell according to claim 1, characterized in that: The solid content of the ink is 40-60%.

9. A printing process using the ink according to any one of claims 1 to 8, characterized in that: The steps include: S1, applying ink to the side of the battery cell by roller printing to form an ink coating on the side of the battery cell; S2, drying the ink coating by hot air or infrared rays; S3, performing copper electroplating on the upper side and / or the lower side of the battery cell to form an electroplated copper layer on the upper side and / or the lower side of the battery cell; S4. Soak the ink coating with alkali to remove the ink coating from the side of the battery cell.

10. The printing process according to claim 9, characterized in that In S1, the thickness of the ink coating was 10–30 μm; In S2, the temperature of the ink coating is 100-120 degrees and the time is 1-5 minutes; In S3, the thickness of the electroplated copper layer is 6 to 12 μm; In S4, the alkali solution is a 3-5% potassium hydroxide aqueous solution, the soaking temperature is 40-50°C, and the soaking time is 1-10 minutes.

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