Throughout the history of the solar photovoltaic industry, cost reduction and efficiency enhancement is an eternal trend. At present, the most mature PERC solar cells have reached the limit of efficiency. With the maturity of new technologies TOPCon and HJT, a new round of technological changes is imminent. On June 28, King Kong Glass announced that it will invest 832 million yuan to build a 1.2GW HJT battery and module project. It can be seen that new entrants are more willing to choose HJT, while PERC's veteran leaders are more willing to try TOPCon. What is the reason behind it? ?

1. Solar Photovoltaic history review

Looking back at the development history of photovoltaics, how to improve conversion efficiency and reduce costs so that the rate of return on investment approaches or even exceeds that of thermal power generation is the driving force for the industry to move forward.

At present, the conversion efficiency of Solar PERC Cells is close to the theoretical limit of 24%, and the industry has begun to prepare for the mass production of next-generation cells technologies. At present, the focus of the market is mainly on Topcon and HJT (heterojunction cells).

2. TOPCon: can be transformed on the basis of PERC

In addition to breaking through the limit conversion efficiency of PERC cells, the TOPCon cell process can be modified on the basis of PERC. The main difference from the PERC cell process is the addition of steps such as boron expansion and tunnel oxide deposition.

Now the Solar PERC production line is huge, and if it is eliminated directly, it will cause greater losses. Therefore, if TOPCon can extend the life of the existing production line, manufacturers are very motivated to try. In addition, the current equipment cost of HJT is still relatively high (about 450 million yuan), and the cost of TOPCon transformation is about 150 million yuan.

3. HJT: The cost reduction path is clear and the potential is great

HJT, its advantages are that the theoretical conversion efficiency is as high as 27%, only 4 steps are required, no light decay, good temperature characteristics and so on. The disadvantage is that the current equipment cost is 450 million yuan/GW, which is relatively high.

4. How is HJT's cost reduction going? When will it be mass-produced?

The industry believes that in 2022, HJT will achieve the ability to directly compete with PERC batteries. Therefore, 2021 is the first year of HJT's budding, and the equipment order situation is the best proof.

5. HJT's future imagination: laminated cells

HJT cells technology will most likely not be the end of Solar photovoltaic cell technology. The future HJT/perovskite tandem cells may be the future, and the conversion efficiency may reach 29%. The characteristics of the two cells are also suitable for making laminated cells.