China's Suzhou Maxwell Technologies Co, Ltd has reported achieving 25.62% power conversion efficiency for monocrystalline silicon heterojunction (HJT) solar cells, using 50% less indium and silver coated copper grid wires.
Maxwell believes the amount of indium can further come down to 30% from the existing level, while the use of silver using this process can also be reduced by 55%. "The combination of these 2 processes alone will significantly reduce the manufacturing cost of HJT cells," it added.
The solar cell equipment supplier said it managed this efficiency on a full size M6 274.5cm² cell with the help of transparent conductive oxides (TCO) process deploying magnetron sputtering. The efficiency claim has been certified by the Institute of Solar Energy Hamelin (ISFH), Germany.
The 144 half-cell M6 HJT cell based solar modules developed by Maxwell's module technology laboratory using this batch of high-efficiency cells have been tested internally – and the power is as high as 491.8W. For reference, a commercially available product based on a similar configuration, i.e. M6 and 144 half cells from Huasun, featured in our Top Modules listing, results in 480 W power rating (see Top Solar Modules Listing — March 2022).
Chinese production equipment maker Maxwell claims the efficiency of 25.62% is currently a record high for this kind of cell which will enable a significant reduction in the manufacturing costs of HJT cells. The reduction of silver and indium is sure to excite the industry as these happen to be 2 of the most expensive elements of a solar cell production process. Recently, LONGi Solar claimed 25.40% efficiency for indium-free HJT cells (see 25.04% Efficiency For Indium-Free HJT).
In March 2022, Maxwell along with Australian metallization technology company SunDrive announced a full area conversion efficiency of 26.07% for a M6 HJT cell using a mass manufacturing process and with no silver (see 26.07% Efficiency Record For HJT Solar Cell).