The evolution of solar cell size can be roughly divided into three stages.The first stage was from 1981 to 2012, when the wafer size increased from 100mm and 125mm to 156mm (i.e. M0).At the end of 2013, Longi, Zhonghuan, crystal dragon, sun energy, kamm Dan 5 companies jointly issued 156.75 mm standard M1 (205 mm) in diameter and M2 (210 mm) diameter of silicon, the M2 silicon thanks to not change the component area and boost power component, quickly become the industry mainstream silicon wafer size after 2017, 85% market share, gain a silicon wafer size for the second time change.Since the second half of 2018, as the battery conversion efficiency, break through the difficulty to increase wafer size again, when so many companies are overweight, tear apart the 158.75 mm (G1) silicon is not a corner the market, market share of only 10%, 2019 Longi has shouldered the "166" (M6), Zhonghuan stake to 210 mm (M12, later changed to a G12), crystal follow up to start the 163 mm, the third silicon open change.

The fundamental logic behind the continuous evolution of silicon wafer size is that compared with the difficulty of improving battery efficiency, large silicon wafer can reduce cost and increase efficiency immediately.

The silicon wafer end, the large silicon wafer brings the production speed greatly increased, the corresponding unit cost greatly decreased;

On the battery side, the larger the wafer area is, the greater the output will be, thus increasing the capacity and reducing the unit cost.

On the component side, the larger silicon wafer brings less chip spacing ratio, the conversion efficiency and output power of the component are expected to be improved, and other costs outside the battery are diluted.

At the system end, with the increase of component power, the number of components decreases, and the related auxiliary materials such as junction box, cable and bus box decrease synchronously, thus reducing the initial investment.

According to calculation, compared with the current mainstream 156.75mm (M2) silicon wafer, 166mm silicon wafer in the battery link, each watt can reduce 0.025 RMB;

At the component end, the cost per watt is also reduced by 0.025 RMB.

At the end of the system, a 425WP component using 166mm silicon wafers will save at least 0.05 /W BOS cost compared to a 380WP component using M2 silicon wafers if the 72 plate type is adopted.
For 210mm silicon wafers, Data shows that the cost of battery wafers is 25.56% lower than that of M2, while the cost of components is 16.8% lower.

In power station construction, 210mm saves 12% BOS cost compared with 166mm, and the corresponding LCOE decreases by 4.1%.

However, it needs to be emphasized that, with the adjustment and expansion of silicon wafer size, the existing production equipment of the industry chain also poses a challenge.