As a sustainable green industry, the photovoltaic industry is attracting more and more attention. To achieve carbon neutrality, national policies that benefit the photovoltaic industry have been continuously introduced in recent years, which has also promoted the rapid development of the photovoltaic industry. At present, crystalline silicon cells and their related products are the mainstream products in the photovoltaic industry, occupying a major share of the photovoltaic market. The information of each production link of the crystalline silicon photovoltaic industry is collected and investigated, combined with Michael Porter's five forces models to conduct in-depth research and analysis, and put forward corresponding countermeasures and suggestions.

The photovoltaic industry is a national strategic emerging industry with great development potential. In addition, China is very rich in solar energy resources, and has unique resource advantages in the development and utilization of solar energy. The current situation and development trend of each production link of crystalline silicon photovoltaic industry were investigated, and were analyzed with the help of Michael Porter's five forces analysis model;  relevant enterprise development strategies were proposed.
 
1. Development status of each production link in the crystalline silicon industry
1.1 Polycrystalline silicon ingots and monocrystalline silicon rods
Silicon is still the most important factor affecting the cost of crystalline silicon cell series products. In order to reduce costs and the loss of silicon, increasing the size of silicon ingots or rods, and the size of silicon wafers and reducing the thickness of silicon wafers will be the constant development trend of all upstream links in the crystalline silicon industry. At present, the size of polycrystalline silicon ingots is gradually developing from G6 and G7 to G8, and the weight of silicon ingots has gradually increased from 800kg to more than 1000kg. According to the forecast of ITRPV 2020, the weight of polycrystalline silicon ingots may increase to 1200kg by 2024. At present, the mainstream product of polycrystalline silicon ingots is high-efficiency polycrystalline silicon ingots. The single-crystal silicon ingot casting technology has a low degree of industrialization due to its costs and technical limitations. Compared with polysilicon, the market share of monocrystalline silicon is much higher than that of polycrystalline silicon because end customers prefer monocrystalline products with lower comprehensive costs and higher conversion efficiency. The continuous crystal pulling process based on the Czochralski growth method and the multiple feeding method is still the main method for producing single crystal silicon rods. In contrast, although the zone melting method and the magnetic field Czochralski method can reduce the oxygen content, its market competitiveness and current market share are far less than that of the monocrystalline silicon produced by the traditional Czochralski method.
 
1.2 Silicon Wafers
In recent years, the silicon wafer's cutting process of the crystalline silicon photovoltaic industry has mainly developed around the direction of large-sized and thin silicon wafers. Increasing the size of the silicon wafer can increase the power of the components and reduce the cost. The sizes of silicon wafers produced in the industry mainly include 157mm, 157.75mm and 158.25mm, and are gradually advancing to large sizes such as 166mm, 182mm, and 210mm. In addition, thinning is another development trend in silicon wafer. In recent years, the thickness of silicon wafers has been reduced from 210um and 200um to 180um and 170um, and it is still decreasing. For example, some companies already have the cutting technology of140um for a single crystal.
 
1.3 Cells
High efficiency and low costs are the constant development direction of crystalline silicon solar cells. PERC cells are the mainstream of crystalline silicon high-efficiency cells in recent years. The advantage is that the passivation layer on the back can effectively reduce the surface recombination loss, and the cell efficiency can be improved by more than 2% compared with the traditional all-aluminum back field cell, generally higher than 22%, which is an important technological breakthrough. In addition, the process flow of PERC batteries is highly compatible with traditional battery production lines, and it is easy to realize the conversion and mass production of new and old battery production lines. Therefore, the PERC battery has occupied a considerable market share for a long time. By the end of 2019, China's domestic PERC cell capacity reached 113GW. After PERC cell technology, several new high-efficiency cell technologies have been developed in the industry. The n-PERT cell is based on the backside passivation technology of N-type cells, which has the advantages of low light decay and can be made into double-sided cells. The development of TOPCon cells provides further room for efficiency improvement for n-PERT cells.
 
This battery uses the tunnel oxide layer passivation contact battery technology, and its battery process is highly compatible with the production line of PERT batteries, so the speed of large-scale production is also faster. Up to now, the mass production efficiency of TOPCon batteries of many companies has exceeded 24%, and the production capacity is also increasing. In addition, HJT batteries and IBC batteries have also attracted more attention. The industrialization speed is slow due to their complex manufacturing process and high costs.
 
1.4 Modules
Compared with thin-film modules, crystalline silicon modules still have an absolute advantage in market share. By the end of 2019, P-type PERC monocrystalline modules (60 pieces and 320W), N-type PERT or TOPCon monocrystalline modules (60 pieces and 330W), black silicon polycrystalline modules (60 pieces and 285W), black silicon plus PERC polycrystalline modules (60 pieces and 300W) and PERC monocrystalline modules (60 pieces and 315W) are the mainstream products on the market. With the development of the crystalline silicon photovoltaic industry, the market demand for high-efficiency and high-power modules continues to rise. The main factors affecting the conversion efficiency of modules are optical loss and electrical loss. The optimization methods for optical loss mainly include the application of materials and technologies such as reflective films or reflective solder strips, white EVA, high-reflective backplanes, high-transparency glass, triangular solder strip splicing technology, solder strip shaping technology, and half-block interconnection technology. The optimization methods for electrical losses mainly include the development and application of half-cell modules, multi-busbar modules and shingled technology. At present, these technologies are used in the industry, but the technical routes that different manufacturers focus on are different. As mentioned in the 2019 to 2020 Annual Report of China's Photovoltaic Industry, the bifacial module technology of half-cell plus multi-busbar plus large-size silicon wafer may become the most competitive technology in the next few years.