● 9th Solar Cell Paste and Metallization Forum 2023 will be held virtually through Zoom on line.
● Simultaneous interpretation from Chinese to English will be available.
● More than 300 industry professionals from the upstream and downstream industry chains of Solar Cell Paste and Metallization will gather to discuss industry plans!
The development of N-type cell technologies such as TOPCon and HJT is continuing to promote the growth of the PV silver paste market. At present, the PV industry is actively promoting the metallization cost of TOPCon and HJT cells to achieve large-scale development of N-type cells. Especially for HJT cells, in terms of physical performance, the conductivity of HJT cell low temperature silver paste is weaker than that of high temperature silver paste. For PERC cells, the demand for HJT metallization technology innovation will be more urgent.
On the premise of not affecting the conversion efficiency of the cell, a lower-priced metal is used to replace a part of the silver powder to reduce the use of precious metal silver, so as to achieve the effect of cost reduction. The specific methods include copper electroplating and silver coated copper. The silver coated copper process still requires screen printing equipment. At present, mainstream companies in the industry are all verifying the silver coated copper paste, and it is expected to enter mass production in 2023.
According to the technical path of narrowing the grid line width, SMBB and even 0BB processes have emerged for PV cells, and silver-coated copper paste is also being used at the material. According to the prospectus of Fusion, the number of busbar in the market in 2021 was about 10BB and the width of finger was controlled at an average of 27μm. It is estimated that the width of the finger will decrease to 20μm by 2022. According to the Boamax HJT production plan, the consumption of silver paste in the initial design is about 22mg/W, and the production consumption is about 19mg/W after the ramp up of mass production. It will be optimized to 10mg/W after using the silver-coated copper technology. "Low silver consumption" has made some progress but is still in the trial stage. Copper electroplating is more likely to become the ultimate route to reduce the cost of PV "silver removal".
Copper electroplating is a non-contact electrode metallization technology. Metal copper is deposited on the base metal surface by electrolytic method to produce copper grid lines, which are used to collect carriers generated. Copper electroplating is the next generation metallization technology for silicon solar cells, especially for HJT cells. Copper electroplating can replace silver paste with copper, which can greatly reduce the consumption of low-temperature silver paste. In addition, compared with low-temperature silver paste, it can produce grid lines with stronger conductivity and narrower width. According to Asiachem's Annual Report on “Conductive Paste and Metallization of Solar Cells in China 2022”, the advantages and disadvantages of screen printing process and copper electroplating for HJT cell are shown in the following table.
Low temperature silver paste+screen printing | Copper electroplating | |
Advantage | Mature technology; The steps are simple, the graphics can be formed at one time and multiple graphics can be printed; Large output and mature equipment | Better aspect ratio; Lower electrode ohmic loss; The loss of shading is reduced; Improve conversion efficiency; Cost reduction |
Disadvantage | How to further reduce the electrode width; Reduce the resistivity of low-temperature silver paste; Large consumption of silver paste | Control of complex process flow and yield; Seed layer and mask process lead to higher cost; Chemical stability control; Double-sided electroplating equipment and fixture design; Waste water treatment |
As one of the alternatives to HJT metallization, copper electroplating can achieve cost reduction and improve efficiency. There are many manufacturers in the industry, including Aiko, Longi, Tongwei, Maxwell, SPIC, etc., which actively carry out technical certification. In September 2022, Maxwell and SunDrive have jointly achieved 26.41% of HJT cell efficiency through double-sided microcrystalline process, optimizing the electrode height-width ratio of seedless copper electroplating process. In addition, the 600MW copper electroplating production line of HYM has made positive progress. Boamax has also actively promoted the application of copper electroplating. Equipment manufacturers such as JieDeBao, Sunwell, Dongwei, CFMEE, S.C, and RoboTechnik have all actively deployed.
9th Solar Cell Paste and Metallization Forum 2023 will be held on March 1 in Changzhou, Jiangsu, China. The conference will discuss the PV industry outlook and paste market prospects, the development trend of solar cell technology and metallization processes, the conductive mechanism and contact mechanism of silver and aluminum paste metallization, the paste and metallization solutions for PERC+, HJT, TOPCon and XBC cells to further improve efficiency and reduce costs, advanced technologies and equipment such as silver coated copper, laser transfer printing, copper electroplating, silver aluminum paste and busbar-free, metallization process for perovskite tandem solar cell, etc. This conference will provide ZOOM Global Online Participation and simultaneous interpretation in Chinese and English.
