Wafer Sizes And their Market Share

As to the story of larger wafers, manufacturing was one of the greatest concerns all along the value chain. All the three important process steps – wafering, cell processing and module making – require different degrees of adaptation of processing tools and production practices.
Silicon ingot growing and subsequent wafering, which are often clubbed together, is where the change starts from. The important modifications and corresponding implications in this section of PV manufacturing have been discussed in detail in the Wafer section of TaiyangNews Report on 500W+ Solar Modules. The current report summarizes the recent developments.
As can be expected, wafering is subject to continuous optimization with respect to larger formats. One such update was shared by JA Solar at TaiyangNews Virtual Conference on High Efficiency Solar Technologies held in the first week of December 2020. According to the company, the pulling rate for a silicon ingot suitable for the 182 mm wafer format is the same as that of the ingot used for G1/M6. Even the utilization rate of the ingot, which means the proportion of an ingot qualified for wafer production, is also the same as of now, underlying the scope for future improvements in pulling rate and ingot yield.
However, performance parity had not been achieved at that time at the wafering station. While 40/38 μm thin diamond wire is used for the production of G1 wafers, M10 wafer slicing is accomplished with a slightly thicker wire of 40/45 μm. As a result, the overall wafering yield is slightly higher by 1% with smaller wafers, while the slicing yield is particularly the same for both the wafer formats. The company said it expects to reach parity very soon.
When the comparison is between M10 and G12, manufacturers choose a favourable scenario. LONGi, for example, emphasized during the same conference that wafering costs are slightly higher for G12 by about 0.15 to 0.3 US cents/W due to relatively slower pulling rates required for growing ingots with larger diameters and also due to the complexity involved in controlling oxygen content. The wafer thickness needs to be slightly higher to maintain mechanical strength due to a larger surface area.
Risen, on other hand, presented the results favouring G12 format at TaiyangNews Virtual Conference on Advanced Solar Modules in Jan 2021. 210 mm would increase the production weight of monocrystalline silicon per unit time compared to 182 mm. Putting this into perspective, Risen found that the yield in the crystal growth segment would increase by about 15%, reducing the silicon side of costs. In wafering, the G12 format improves the production yield in terms of area per each sawing tool, which is why Risen estimated benefits to be greater than 5% over its key contender.
Since the wafer size development took hold at a very fast pace, the year 2020 had several wafer sizes around: namely, 156.75 mm (M2), 157 mm (M2+), 158.75 mm (G1), 166 mm (M6), 182 mm (M10) and 210 mm (G12). Each of these wafer sizes had a certain share in the market in 2020. The G1 and M6 wafers – representing the easiest and upper limit for upgrade possibility of the cell production lines – were still the mainstream wafer sizes in 2020. According to the China Photovoltaic Industry Association (CPIA) roadmap, G1 and M6 accounted for as much as 78% of the market. M2 still had a sizeable share in 2020, which is expected to fade away by around 2022. While M6 is expected to be around for a few more years, M10 and G12, which put together had a share of less than 5% in 2020, are expected to gain very rapid market share in this year, representing half of the total market and eventually dominate the segment in the coming years.
The text is an excerpt from the TaiyangNews Report on Very High Power Solar Modules: Summarizes Most Notable Developments Along Manufacturing And PV Value Chain for Panels Based on Large Wafers & Provides Overview on Latest Products of Leading Module Suppliers – The TaiyangNews Market Survey Report can be downloaded for free here.
At TaiyangNews' Virtual Conference on Very High-Power Solar Modules, Shravan Chunduri, Head of Technology for TaiyangNews emphasizes that using larger wafers to attain higher power modules has more or less become a standard, the recording can be viewed here.