A process for preparing highly conductive electrodes based on inkjet printing of nanosilver paste

Abstract

The invention relates to the field of photovoltaic solar cell manufacturing, and discloses a process for preparing a high-conductivity electrode based on inkjet printing of nano silver paste, comprising the following steps: step one, preparation and selection of nano silver paste; step two, inkjet printing of a seed layer; step three, sintering of the silver paste; step four, copper electroplating process; step five, post-processing; the invention greatly reduces the amount of silver used by using nano silver paste as a seed layer, and the cost is significantly reduced compared with a traditional screen printing silver electrode process; the inkjet printing process avoids complex photolithography and PVD steps, simplifies the preparation process of the seed layer, and improves production efficiency; the inkjet printing process can achieve precise graphic control, ensure that the size and shape of the electrode meet the design requirements, thereby improving the overall performance of the battery; the sintered nano silver seed layer has excellent conductivity, and after being combined with a copper electrode, the conductivity and durability of the electrode are significantly improved.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic solar cell manufacturing, and more specifically, to a process for preparing a high-conductivity electrode based on inkjet printing of nano silver paste. Background Art

[0002] HJT (Heterojunction with Interconnect Thinlayer) solar cells have become a research hotspot in the photovoltaic field due to their high efficiency and low temperature coefficient. Traditionally, the electrodes of HJT cells are usually printed using screen-printed low-temperature curing silver paste, but this method is costly and silver resources are limited. In order to reduce costs, copper electroplating is considered an alternative. However, in order to ensure that copper can be evenly and firmly electroplated on the surface of the cell, it is usually necessary to deposit a copper seed layer on the cell first. Existing seed layer production methods mostly use physical vapor deposition (PVD), which are complex and expensive. Summary of the invention

[0003] In order to overcome the shortcomings of the prior art, the present invention provides a process for preparing a high-conductivity electrode based on inkjet printing of nano silver paste.

[0004] To achieve the above object, the present invention provides the following technical solution: a process for preparing a highly conductive electrode based on inkjet printing of nano silver paste, comprising the following steps:

[0005] Step 1: Preparation and selection of nano silver paste;

[0006] Step 2: inkjet printing of seed layer;

[0007] Step 3: Sintering of silver paste;

[0008] Step 4: copper electroplating process;

[0009] Step 5: Post-processing.

[0010] As a preferred technical solution of the present invention, in the step one, a nano silver paste suitable for inkjet printing is selected, and the particle size of the silver paste particles should be controlled between 20 and 100 nanometers to ensure the accuracy of inkjet printing and the conductivity of the silver layer; the silver paste has a suitable viscosity and surface tension to ensure that it can form a uniform pattern during the inkjet printing process and can be well combined with the surface of the HJT battery.

[0011] As a preferred technical solution of the present invention, in step 2, an inkjet printing device is used to print nano silver paste on a predetermined area of ​​the HJT battery to form a seed layer. The inkjet-printed graphics can be precisely controlled according to the battery design requirements, such as gate lines, buses or other conductive paths; during the printing process, the layer thickness and width of the silver paste are controlled to ensure the continuity and uniformity of the seed layer. Typically, the seed layer has a thickness of 100 to 500 nanometers and a width of 5 to 25 microns.

[0012] As a preferred technical solution of the present invention, the specific process in step three is that after printing is completed, the HJT battery is placed in an oven or furnace for heat treatment to sinter the silver paste. The sintering temperature should be controlled at 150-300°C to promote the interconnection of silver nanoparticles, thereby improving the conductivity of the seed layer. The temperature and time during the sintering process need to be optimized according to the characteristics of the silver paste to ensure the formation of a dense silver seed layer without damaging other structures of the HJT battery.

[0013] As a preferred technical solution of the present invention, in step 4, the sintered HJT battery is placed in a copper electroplating solution for electroplating. Through electrochemical methods, copper ions are deposited on the silver seed layer to form a copper electrode with uniform thickness and good adhesion; electroplating parameters such as current density, time and temperature should be adjusted according to the battery design requirements to ensure the thickness and uniformity of the electrode.

[0014] As a preferred technical solution of the present invention, in step five, after the electroplating is completed, the HJT battery is cleaned to remove the electrolyte or other impurities remaining in the electroplating process; then the finished battery is performance tested to ensure that the conductivity, adhesion and overall battery efficiency of the electrode meet the design standards.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention uses nano silver paste as a seed layer, which greatly reduces the amount of silver used and significantly reduces the cost compared to the traditional screen printing silver electrode process.

[0017] The inkjet printing process of the present invention avoids complicated photolithography and PVD steps, simplifies the preparation process of the seed layer, and improves production efficiency;

[0018] The inkjet printing process of the present invention can achieve precise graphic control, ensuring that the size and shape of the electrode meet the design requirements, thereby improving the overall performance of the battery;

[0019] In the present invention, the sintered nano silver seed layer has excellent conductivity, and after being combined with the copper electrode, the conductivity and durability of the electrode are significantly improved. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] Embodiment 1:

[0022] A process for preparing a highly conductive electrode based on inkjet printing of nano silver paste comprises the following steps:

[0023] Step 1: Preparation and selection of nano silver paste;

[0024] Nano silver paste is selected as a raw material, and the particle size of the nano silver paste particles is 60 nanometers; the nano silver paste is combined with the surface of the HJT battery to form a uniform pattern according to printing.

[0025] Step 2: inkjet printing of seed layer;

[0026] An inkjet printing device is used to print nano silver paste on a predetermined area of ​​the HJT battery to form a seed layer; the inkjet-printed graphics are controlled according to the battery design requirements, specifically including but not limited to gate lines, buses, and other conductive paths; the seed layer has a thickness of 280 to 320 nanometers and a width of 13 to 16 microns.

[0027] Step 3: Sintering of silver paste;

[0028] After printing is completed, the HJT battery with the seed layer is placed in an oven or furnace for heat treatment to sinter the silver paste; the sintering temperature is 200°C and the sintering time is 30 minutes.

[0029] Step 4: copper electroplating process;

[0030] The sintered HJT battery is placed in a copper electroplating solution for electroplating at a current density of 2A / dm 2 , the electroplating time is 10 minutes, and copper ions are deposited on the silver seed layer to form a copper electrode with uniform thickness.

[0031] Step 5: Post-processing;

[0032] After electroplating is completed, the HJT battery is cleaned to remove residual electrolyte or other impurities from the electroplating process; the finished battery is then performance tested to ensure that the conductivity, adhesion and overall battery efficiency of the electrode meet the design standards.

[0033] Embodiment 2:

[0034] A process for preparing a highly conductive electrode based on inkjet printing of nano silver paste comprises the following steps:

[0035] Step 1: Preparation and selection of nano silver paste;

[0036] Nano silver paste is selected as a raw material, and the particle size of the nano silver paste particles is 80 nanometers; the nano silver paste is combined with the surface of the HJT battery to form a uniform pattern according to printing.

[0037] Step 2: inkjet printing of seed layer;

[0038] An inkjet printing device is used to print nano silver paste on a predetermined area of ​​the HJT battery to form a seed layer; the inkjet-printed graphics are controlled according to the battery design requirements, specifically including but not limited to gate lines, buses, and other conductive paths; the seed layer has a thickness of 380 to 420 nanometers and a width of 22 to 24 microns.

[0039] Step 3: Sintering of silver paste;

[0040] After printing is completed, the HJT cell with the seed layer is placed in an oven or furnace for heat treatment to sinter the silver paste; the sintering temperature is set at 250°C and the time is 20 minutes.

[0041] Step 4: copper electroplating process;

[0042] The sintered HJT battery is placed in a copper electroplating solution for electroplating. The copper electroplating parameters are a current density of 3A / dm 2 , the time is 8 minutes, copper ions are deposited on the silver seed layer to form a copper electrode with uniform thickness.

[0043] Step 5: Post-processing;

[0044] After electroplating is completed, the HJT battery is cleaned to remove residual electrolyte or other impurities from the electroplating process; the finished battery is then performance tested to ensure that the conductivity, adhesion and overall battery efficiency of the electrode meet the design standards.

[0045] Embodiment three:

[0046] A process for preparing a highly conductive electrode based on inkjet printing of nano silver paste comprises the following steps:

[0047] Step 1: Preparation and selection of nano silver paste;

[0048] Nano silver paste is selected as a raw material, and the particle size of the nano silver paste particles is 30 nanometers; the nano silver paste is combined with the surface of the HJT battery to form a uniform pattern according to printing.

[0049] Step 2: inkjet printing of seed layer;

[0050] An inkjet printing device is used to print nano silver paste on a predetermined area of ​​the HJT battery to form a seed layer; the inkjet-printed graphics are controlled according to the battery design requirements, specifically including but not limited to gate lines, buses, and other conductive paths; the seed layer has a thickness of 120 to 160 nanometers and a width of 5 to 8 microns.

[0051] Step 3: Sintering of silver paste;

[0052] After printing is completed, the HJT battery with the seed layer is placed in an oven or furnace for heat treatment to sinter the silver paste; the sintering temperature is 150°C and the time is 20 minutes.

[0053] Step 4: copper electroplating process;

[0054] The sintered HJT battery is placed in a copper electroplating solution for electroplating. The copper electroplating parameters are a current density of 5A / dm 2 , the time is 5 minutes, copper ions are deposited on the silver seed layer to form a copper electrode with uniform thickness.

[0055] Step 5: Post-processing;

[0056] After electroplating is completed, the HJT battery is cleaned to remove residual electrolyte or other impurities from the electroplating process; the finished battery is then performance tested to ensure that the conductivity, adhesion and overall battery efficiency of the electrode meet the design standards.

[0057] A method for making HJT solar cell electrodes by inkjet printing of nano silver paste to form a seed layer and then performing copper electroplating. This method simplifies the manufacturing process, reduces production costs, and ensures the high efficiency of the battery, and has broad industrial application prospects.

[0058] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0059] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing a highly conductive electrode based on inkjet printing of nano silver paste, characterized in that: The steps include: Step 1: Preparation and selection of nano silver paste; Step 2: inkjet printing of seed layer; Step 3: Sintering of silver paste; Step 4: copper electroplating process; Step 5: Post-processing.

2. The process for preparing a highly conductive electrode based on inkjet printing of nano silver paste according to claim 1, characterized in that: In the step 1, nano silver paste is selected as the raw material, and the particle size of the nano silver paste particles is between 20 and 100 nanometers; the nano silver paste is combined with the surface of the HJT battery to form a uniform pattern according to printing.

3. The process for preparing a highly conductive electrode based on inkjet printing of nano silver paste according to claim 1, characterized in that: In the step 2, an inkjet printing device is used to print nano silver paste on a predetermined area of ​​the HJT battery to form a seed layer.

4. The process for preparing a highly conductive electrode based on inkjet printing of nano silver paste according to claim 1, characterized in that: In the step 2, the graphics printed by inkjet printing are controlled according to the battery design requirements, specifically including but not limited to gate lines, buses, and other conductive paths; the thickness of the seed layer is between 100 and 500 nanometers, and the width is between 5 and 25 micrometers.

5. The process for preparing a highly conductive electrode based on inkjet printing of nano silver paste according to claim 1, characterized in that: The specific process in step three is that after printing is completed, the HJT battery with the seed layer is placed in an oven or oven for heat treatment to sinter the silver paste.

6. The process for preparing a highly conductive electrode based on inkjet printing of nano silver paste according to claim 1, characterized in that: In the step three, the sintering temperature is 150°C to 300°C.

7. The process for preparing a highly conductive electrode based on inkjet printing of nano silver paste according to claim 1, characterized in that: In the step 4, the sintered HJT battery is placed in a copper electroplating solution for electroplating, and copper ions are deposited on the silver seed layer to form a copper electrode with uniform thickness.

8. The process for preparing a highly conductive electrode based on inkjet printing of nano silver paste according to claim 1, characterized in that: In the step five, after the electroplating is completed, the HJT battery is cleaned to remove the residual electrolyte or other impurities in the electroplating process; then the finished battery is subjected to performance testing to ensure that the conductivity, adhesion and overall battery efficiency of the electrode meet the design standards.