Traditionally, monocrystalline silicon solar cell wafers before 2010 were classified as small-size with 125mm x 125mm width (164mm silicon ingot diameter) and only a small number at 156mm x 156mm (200mm silicon ingot diameter), which had been the dominant ingot size in the semiconductor industry until leading companies adopted 300mm diameter ingots.

Monsoon Wang, Director of Product Marketing at LONGi Solar told that the wafer size change  is occurring faster than many people realise.

“Yes, this trend is happening,” noted Wang. “Only ten years ago, almost all the mono wafers were 125mm. A few years later some producers were starting to supply 156mm wafers and we have seen that these almost complete transitions can take two to three years. So by 2014, the transition to 156mm wafers had happened. The reason for this change is that the wafers were much smaller and production costs much higher as the overall capacity was much lower than for multi. This was the driver for all cell producers to switch to the then larger wafer size.”

After 2010, 156mm x 156mm wafers increasingly became the popular choice (lower cost per-watt) for p-Type mono and multi wafer sizes. As a result of the lower production costs, 125mm x 125mm P-type wafers were almost eliminated from the market by 2014, with only some IBC and HJT cells using the 125mm x 125mm n-Type wafers as the larger size technology lagged P-type investments due to the niche nature of the applications.

By the end of 2013, a number of China-based wafer producers (LONGi, Zhonghuan, Jinglong, Solargiga and Comtec) jointly issued the standards for (M2) 156.75 x 156.75 p-Type mono wafers (205mm diameter silicon ingot) and (M2) 156.75 x 156.75 p-Type mono wafers (210mm diameter silicon ingot).

Without increasing the overall dimensions of a 60 cell module, M2 wafers could increase  module power by more than 5wp, a significant boost for a competitive cost per-watt, thus rapidly becoming the mainstream and maintaining that status for several years.

During that period, there were also a few (M4) 161.7mm x 161.6mm (211mm diameter silicon ingot) wafers on the market, the area of which was 5.7% larger than an M2, and these were mainly used for n-Type bifacial modules.

The move from 156mm x 156mm to the larger formats of 156.75mm x 156.75mm in mass production started in 2016. The old 6” format (156mm x 156mm) we all recognise is expected to disappear completely from the market by the end of 2019, according to the 2019 edition of the survey.

However, a transition to a new larger ‘standard’ wafer size is going to prove difficult, as will comparing cell/module conversion efficiencies on a like for like basis going forward.

The industry is transitioning faster than expected and key PV module manufacturers are ramping mono-Si wafer capacity, which is compatible with the production of larger silicon wafers. Multicrystalline wafer sizes are also expected to follow suit. The dominant format is 156.75 x 156.75 in mass production but, according to the ITRPV 2019 edition, other sizes are also emerging in mass production, such as 157 x 157 and even a larger format at 158.75 x 158.75, could be the standard for the next few years.

Larger formats are expected to enter production at some point, including 166mm x 166mm, which could gain a 15% market share over the next 10 years. Even larger formats are not ruled out in the latest survey.

Bluesun 166mm solar panels are very popular by worldwide customers. 144cell half cut perc mono 440w pv module,mono 445w pv module has totally 5MW Inventory at our warehouse in China.

If you want to get more information, please contact us at info@bluesunpv.com or call us at +86 158 5821 3997