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CN-121976269-A - Copper electroplating solution, preparation method and application thereof, solar cell and photovoltaic module

CN121976269ACN 121976269 ACN121976269 ACN 121976269ACN-121976269-A

Abstract

The invention provides copper electroplating solution, a preparation method and application thereof, a solar cell and a photovoltaic module, and relates to the technical field of solar cells. The copper electroplating solution comprises a copper ion source, a main complexing agent, an auxiliary complexing agent, conductive salt, a functional additive and water, wherein the functional additive comprises a 2-mercaptobenzimidazole-zinc complex, L-ascorbic acid, 3-mercapto-1-propanesulfonic acid sodium, polyaspartic acid sodium and water. The copper electroplating solution has no corrosion to a silicon substrate and a passivation layer, ensures the structural integrity of a battery, realizes high-efficiency deposition of a compact low-resistance copper layer through the synergistic effect of a double-complexing system and a functional additive, improves the conductivity and interface binding force, and simultaneously, enhances the copper-silver adhesion of a formed chemical bonding interface, remarkably improves the electrical property and long-term reliability of the battery, and is suitable for large-scale manufacturing of high-performance back contact solar batteries.

Inventors

  • TANG YIWU
  • GUAN TONGZHOU
  • SONG NAN

Assignees

  • TCL中环新能源科技股份有限公司

Dates

Publication Date
20260505
Application Date
20260203

Claims (10)

  1. 1. A copper electroplating solution is characterized by comprising a copper ion source, a main complexing agent, an auxiliary complexing agent, conductive salt, a functional additive and water; Wherein the functional additive comprises a 2-mercaptobenzimidazole-zinc complex, L-ascorbic acid, 3-mercapto-1-propanesulfonic acid sodium salt, polyaspartic acid sodium salt and water.
  2. 2. The copper plating solution according to claim 1, wherein the copper plating solution comprises 20-80 g/L of a copper ion source, 50-150 g/L of a main complexing agent, 40-120 g/L of an auxiliary complexing agent, 50-100 g/L of a conductive salt, 0.5-3.0 mL/L of a functional additive, and water as a solvent; Preferably, the functional additive comprises, by mass, 1-5% of a 2-mercaptobenzimidazole-zinc complex, 30-60% of L-ascorbic acid, 0.2-2% of 3-mercapto-1-propanesulfonic acid sodium salt, 10-25% of polyaspartic acid sodium salt and the balance of water; Preferably, the pH of the copper electroplating solution is 6.5-7.5; Preferably, the copper plating solution further comprises a pH regulator; Preferably, the pH regulator is selected from an ammonia water solution and/or an sulfamic acid solution, wherein the mass percentage of NH 3 in the ammonia water solution is 25-30%, and the mass percentage of sulfamic acid in the sulfamic acid solution is 5-10%.
  3. 3. The copper plating solution according to claim 1 or 2, wherein the copper ion source is selected from any one or a combination of at least two of basic copper carbonate, copper oxide, copper sulfate, copper nitrate, and copper acetate; preferably, the main complexing agent is selected from any one or a combination of at least two of ethylenediamine tetraacetic acid, hydroxyethyl ethylenediamine triacetic acid, diethylenetriamine pentaacetic acid and nitrilotriacetic acid; Preferably, the auxiliary complexing agent is selected from any one or a combination of at least two of ammonium citrate, trisodium nitrilotriacetate, potassium sodium tartrate, diammonium hydrogen phosphate and potassium pyrophosphate; Preferably, the conductive salt is selected from any one or a combination of at least two of ammonium sulfamate, ammonium sulfate and ammonium nitrate.
  4. 4. A method for producing the copper plating solution according to any one of claims 1 to 3, characterized by comprising: and mixing a copper ion source, a main complexing agent, an auxiliary complexing agent, conductive salt, a functional additive and water, and curing to obtain the copper electroplating solution.
  5. 5. The method for preparing a copper plating solution according to claim 4, wherein the method for preparing the functional additive comprises the steps of: in a weak alkaline solution, reacting 2-mercaptobenzimidazole with zinc salt to obtain 2-mercaptobenzimidazole-zinc complex solution; Mixing 2-mercaptobenzimidazole-zinc complex solution, L-ascorbic acid, 3-mercapto-1-propanesulfonic acid sodium, polyaspartic acid sodium and water, and filtering to obtain the functional additive; Preferably, the molar ratio of the 2-mercaptobenzimidazole to the zinc salt is (1.8-2.2): 1; preferably, the zinc salt is zinc sulfate; Preferably, the weakly alkaline solution is an ammonia water solution, wherein the mass percentage of NH 3 in the ammonia water solution is 5-15%, and the mass ratio of the weakly alkaline solution to the 2-mercaptobenzimidazole is (8-15): 1; Preferably, the temperature of the reaction is 40-60 ℃, and the reaction time is 1.0-2.0 h; Preferably, the mixing comprises mixing L-ascorbic acid, sodium polyaspartate and water, stirring for the first time, mixing with 2-mercaptobenzimidazole-zinc complex solution and sodium 3-mercapto-1-propanesulfonate, and stirring for the second time; preferably, the rotating speed of the first stirring is 200-400 rpm, and the time of the first stirring is 1.0-2.0 h; Preferably, the rotating speed of the second stirring is 100-250 rpm, and the time of the second stirring is 0.5-1.0 h.
  6. 6. The method for producing a copper plating solution according to claim 4, wherein the method for producing a copper plating solution comprises: mixing the conductive salt, the main complexing agent, the auxiliary complexing agent and part of water, and stirring for the first time to obtain a mixed solution I; Mixing the first mixed solution with a copper ion source, and stirring for the second time to obtain a second mixed solution; Regulating the pH value of the mixed solution II, mixing with the functional additive and the residual water, and curing to obtain the copper electroplating solution; preferably, the partial water accounts for 50-60% of the total volume of the water; preferably, the rotating speed of the first stirring is 150-300 rpm, and the time of the first stirring is 0.5-1.0 h; preferably, the rotating speed of the second stirring is 200-400 rpm, and the time of the second stirring is 1.0-2.0 h; preferably, the pH of the second mixed solution is adjusted to 6.5-7.5; preferably, the curing treatment is carried out at a temperature of 40-60 ℃ for 2.0-4.0 hours.
  7. 7. Use of the copper plating solution according to any one of claims 1 to 3 for preparing a copper plating solution for back contact solar cells.
  8. 8. A solar cell is characterized by comprising a metal electrode, wherein the metal electrode comprises a silver seed layer and a copper grid line layer which are sequentially stacked, and the copper grid line layer is obtained by electroplating the copper electroplating solution according to any one of claims 1-3; Preferably, the thickness of the silver seed layer is 1-5 μm; preferably, the thickness of the copper grid line layer is 10-15 mu m.
  9. 9. A method of manufacturing a solar cell according to claim 8, comprising: Activating the battery piece with the silver seed layer; Contacting the activated silver seed layer with the copper electroplating solution according to any one of claims 1-3, and performing direct current electroplating to obtain the solar cell; Preferably, hydrochloric acid is used for activation, wherein the concentration of the hydrochloric acid is 5-50 mL/L, and the activation time is 15-60 s; Preferably, the temperature of the copper electroplating solution is 35-50 ℃; Preferably, the direct current electroplated cathode comprises an activated silver seed layer, wherein the direct current electroplated anode comprises phosphorus-containing copper balls and a titanium basket for containing the phosphorus-containing copper balls, and an anode bag is sleeved outside the titanium basket, and the anode bag is made of polypropylene; Preferably, the content of phosphorus in the phosphorus-containing copper ball is 0.04-0.08 wt%: Preferably, the current density of the direct current plating is 1-5A/dm 2 , and the time of the direct current plating is 5-15 min.
  10. 10. A photovoltaic module, characterized in that the photovoltaic module comprises the solar cell according to claim 8 or the solar cell prepared by the preparation method according to claim 9.

Description

Copper electroplating solution, preparation method and application thereof, solar cell and photovoltaic module Technical Field The invention relates to the technical field of solar cells, in particular to copper electroplating solution, a preparation method and application thereof, a solar cell and a photovoltaic module. Background Back contact (Back)Contact, BC for short) solar cell, the positive and negative electrodes are all prepared on the back of the cell, so that the shielding of the front metal grid line to the incident light is thoroughly eliminated, the highest short-circuit current and the beautiful full black appearance are obtained, and the solar cell is one of the most potential structures for realizing the theoretical efficiency limit of the crystalline silicon solar cell. In order to realize cost reduction and efficiency improvement, an electrode scheme of printing a thin silver seed layer and electroplating thick copper is becoming a new research direction. However, the conventional acidic sulfate copper plating solution faces fundamental challenges in the application that the strongly acidic electrolyte can penetrate and corrode a silicon substrate and a passivation layer extremely sensitive to acid through a porous printing silver seed layer or the edge of a grid line, so that the performance of the battery is irreversibly attenuated, a substitution reaction is easy to occur between copper and silver under acidic conditions, a loose copper layer with poor binding force is formed, and although neutral or weakly alkaline copper plating solution is reported in the prior art, the defects of poor plating solution stability, slow deposition rate, insufficient plating compactness, complete failure to consider the specific interface reliability and electrical compatibility requirements of a photovoltaic battery and the like are also present in the prior art. Therefore, there is a need to develop a new copper electroplating solution that is specifically adapted to the back contact solar cell manufacturing process. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide copper electroplating solution, a preparation method and application thereof, a solar cell and a photovoltaic module, and aims to at least solve one of the technical problems in the prior art. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: in a first aspect, the present invention provides a copper plating solution comprising a copper ion source, a primary complexing agent, an auxiliary complexing agent, a conductive salt, a functional additive, and water; Wherein the functional additive comprises a 2-mercaptobenzimidazole-zinc complex, L-ascorbic acid, 3-mercapto-1-propanesulfonic acid sodium salt, polyaspartic acid sodium salt and water. Further, the copper electroplating solution comprises 20-80 g/L of a copper ion source, 50-150 g/L of a main complexing agent, 40-120 g/L of an auxiliary complexing agent, 50-100 g/L of a conductive salt, 0.5-3.0 mL/L of a functional additive, and water as a solvent. Further, the functional additive comprises, by mass, 1-5% of a 2-mercaptobenzimidazole-zinc complex, 30-60% of L-ascorbic acid, 0.2-2% of 3-mercapto-1-propane sodium sulfonate, 10-25% of sodium polyaspartate and the balance of water. Further, the pH of the copper plating solution is 6.5-7.5. Further, the copper plating solution also comprises a pH regulator. Further, the pH regulator is selected from an ammonia water solution and/or an sulfamic acid solution, wherein the mass percentage of NH 3 in the ammonia water solution is 25-30%, and the mass percentage of sulfamic acid in the sulfamic acid solution is 5-10%. Further, the copper ion source is selected from any one or a combination of at least two of basic copper carbonate, copper oxide, copper sulfate, copper nitrate and copper acetate. Further, the main complexing agent is selected from any one or a combination of at least two of ethylenediamine tetraacetic acid, hydroxyethyl ethylenediamine triacetic acid, diethylenetriamine pentaacetic acid and nitrilotriacetic acid. Further, the auxiliary complexing agent is selected from any one or a combination of at least two of ammonium citrate, trisodium nitrilotriacetate, potassium sodium tartrate, diammonium hydrogen phosphate and potassium pyrophosphate. Further, the conductive salt is selected from any one or a combination of at least two of ammonium sulfamate, ammonium sulfate and ammonium nitrate. In a second aspect, the present invention provides a method for producing the copper plating solution according to the first aspect, the method comprising: and mixing a copper ion source, a main complexing agent, an auxiliary complexing agent, conductive salt, a functional additive and water, and curing to obtain the copper electroplating solution. Further, the preparation method of the functional additive compris