As is well known, the photovoltaic power generation industry chain mainly includes five links: silicon materials, silicon wafers, solar cells, battery components, and system application products. Among them, silicon materials and silicon wafers belong to the upstream of the industrial chain; The battery cells and battery components belong to the midstream industrial chain; System application products are downstream links of the industry. According to the chemistry used in the preparation of solar cells, they can be classified into three categories: the first category is crystalline silicon solar cells, mainly including monocrystalline silicon and polycrystalline silicon; The second type is thin-film solar cells, mainly including silicon-based thin-film cells, copper indium gallium selenide cells, cadmium telluride cells, and gallium arsenide cells; The third category is new solar cells, mainly including perovskite cells, dye-sensitized cells, polymer solar cells, and colloidal quantum dot cells. Thin film solar cells and new solar cells have not yet been applied due to their low conversion rate, poor stability, and high manufacturing costs compared to crystalline silicon cells. The mass production technology of thin film solar cells is not yet mature, and new solar cells are still in the laboratory research and development stage. Therefore, the current mass-produced and commercialized batteries are mainly crystalline silicon batteries.
The polysilicon market will experience a turning point
According to statistics from the Silicon Industry Branch, the production capacity of polycrystalline silicon in China has gradually increased from 2015 to 2017, with annual capacities of 169000 tons, 210000 tons, and 276000 tons respectively. In 2016, the growth rate of polycrystalline silicon production capacity was 24.26% compared to 2015, and in 2017, it was 31.43% compared to 2016. From this data, it can be seen that the production capacity of polycrystalline silicon in China has gradually increased until 2017. But according to experts from the Photovoltaic Professional Committee of the China Renewable Energy Society, the main reason for this current situation is that the polycrystalline silicon process is simpler and more cost-effective compared to monocrystalline silicon. As a photovoltaic module for ground power plants, it can bring more short-term benefits to enterprises. However, after the implementation of the "531" policy, photovoltaics will tend to be distributed, the proportion of monocrystalline silicon will gradually increase, and the market for polycrystalline silicon will decrease.
Breakthrough progress in monocrystalline silicon technology
(1) The cutting technology is mature and the cost has been significantly reduced. Both monocrystalline silicon and polycrystalline silicon are first prepared into silicon rods or ingots, and then cut into suitable thicknesses through cutting techniques. The traditional cutting technology mainly uses alloy steel wire to drive silicon carbide abrasive to cut back and forth. In recent years, the technology of using diamond wire instead of diamond wire has rapidly developed in the cutting technology of single crystal silicon. Diamond wire has fast cutting speed, low energy consumption, and significantly reduced silicon material loss. Moreover, this technology has matured in the preparation of single crystal silicon and is moving towards large-scale production, which has greatly reduced the cost of the entire single crystal silicon production process. However, this process has not yet been applied in polycrystalline silicon.
(2) The conversion efficiency of monocrystalline silicon is improved compared to polycrystalline silicon. The core technology for the production of crystalline silicon batteries was previously held by companies in countries such as the United States, Germany, and Japan, until 2005 when they finally mastered the technology. While mass producing, they also focused on improving and developing crystalline silicon battery technology. Recently, the small size single crystal battery jointly developed and synthesized by the State Key Laboratory of Trina Solar Energy Technology has achieved 24.4% laboratory efficiency, while the transformation efficiency of the polycrystalline silicon battery laboratory developed by Trina Solar Technology has only reached 21.25%, which is the highest level at present, creating a world record. In terms of mass production, according to the latest data from the Photovoltaic Professional Committee of the China Renewable Energy Society, the efficiency of ordinary single crystal cells is between 19.6% and 20.2%, while the efficiency of polycrystalline silicon cells is between 18.3% and 18.8%. The conversion efficiency of single crystal silicon modules is higher than that of polycrystalline silicon.
The monocrystalline silicon market is performing well
According to publicly available information, since 2018, the prices of silicon wafers have continued to decline due to policies and the phenomenon of solar abandonment. As of October 24th, the average prices of polycrystalline silicon wafers and monocrystalline silicon wafers have dropped from 4.58 yuan/wafer and 5.25 yuan/wafer at the beginning of the year to 2.12 yuan/wafer and 3.1 yuan/wafer, respectively, with a decrease of 46.2% and 41%. The simultaneous decline in prices of monocrystalline silicon and polycrystalline silicon provides greater choices for paper cups of crystalline silicon solar cells. According to the Photovoltaic Association, in the third quarter of 2018, the production of polycrystalline silicon wafers accounted for 48.6%, a decrease of 2.1 percentage points compared to the previous quarter. The capacity utilization rate in September was 65.2%, a decrease of 2.4 percentage points compared to the previous month. From the data, it appears that when the price competition is not significantly different, the proportion of monocrystalline silicon occupying the market share increases.