Heterojunction batteries are fully called crystalline silicon heterojunction solar cells, also known as HIT, HJT, HDT, SHJ. Is a special PN junction, formed by amorphous silicon and crystalline silicon materials, the technology is deposited on crystalline silicon amorphous silicon thin film, integrated crystalline silicon cells and thin film cells advantages, is considered to be one of the important development directions of high conversion efficiency silicon-based solar cells.
Driven by policies and technologies, the iteration of the industry is like "the back wave pushes the front wave", and the photovoltaic industry is no exception. In the photovoltaic industry, which is constantly pursuing "cost reduction and efficiency improvement", the iterative demand for cells is particularly important. Heterojunction batteries (HJTs), with their huge potential of "efficiency increase and cost reduction", have become the "back wave" of the photovoltaic industry and promote the technological transformation of the photovoltaic industry.
Compared with PERC technology, HJT's cost of all other costs except labor costs is currently higher than PERC. Compared with the current mainstream high-efficiency photovoltaic cell PERC, the core process of heterojunction cells only has four steps: fleece cleaning, amorphous silicon thin film deposition, TCO preparation, and electrode preparation, so the labor cost is relatively low. Consistent with the PERC cost structure, 80% of the cost expenditure comes from the silicon and BOM costs.
First, HJT battery and PERC battery cost distribution
Second, the cost comparison of PERC and HJT batteries
Heterojunction batteries can significantly improve the conversion efficiency of batteries through unique heterojunction structures, and the current mass production efficiency is close to 24%. Its advantages mainly include: (1) high potential for efficiency improvement, through the superposition of IBC or perovskite technology, the maximum efficiency can reach 25%, 28% or more; (2) the cost reduction space is large, low temperature process + N-type cells are easier to achieve silicon wafer thinning; (3) its double-sided symmetry has a higher bifacial rate, and the bifacial battery module can obtain more than 10% of the annual power generation gain; (4) lower photoinvulable attenuation than PERC batteries.
Third, the trend of heterojunction battery conversion efficiency in China from 2016 to 2020
Recently, the HJT conversion efficiency of leading companies has frequently broken records, and HJT efficiency improvement and cost reduction are being cashed in. In October 2021, LONGi's silicon-based heterojunction cell reached 26.3% in terms of conversion efficiency, which is the highest efficiency of the world's crystalline silicon FBC structure battery. In July 2021, Huasheng set a world record of 25.23% conversion efficiency on a 166-size HJT battery.
Fourth, in 2021, China's HJT battery production enterprises conversion efficiency
In 2021, the global HJT planned capacity has reached 148.2GW, of which 6.35GW has been built and 141.9GW is under construction/to be built. 2021-2022 for HJT battery large size supporting equipment and production line inspection stage, the current mass production size to M2, G1, M4 mainly, a small number of enterprises have the ability to produce M6 size, M10, G12 size is still in the research and development stage.
Fifth, in 2021, China's HJT battery production capacity under construction/to be built