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23 July 2020

Chinese solar companies pick sides between 182mm and 210mm

The Chinese photovoltaic industry is seeing a divide over the latest upscaled solar cells and modules, with many companies throughout the manufacturing chain facing a choice between an ‘M12’ group using 210 mm sized wafers, and an ‘M10’ group using 182mm sized wafers – as well as corresponding different sizes at the cell and module level.

Either way, but especially with 210mm, the larger photovoltaic sizes will need manufacturing equipment to be expensively upgraded throughout the supply line. Given the trend to larger sizes and a seemingly greater number of affiliated companies, 210mm could be expected to win out eventually. However, it is less compatible and less tried-and-tested than 182mm, which has the head-start.

There are several technical distinctions between the two groups, such as the prevalence of half-cut cells in the 182mm category, and triple-cutting in the 210mm category. One difference working in favor of 182mm is simply its size when stacked, which is more compatible with the international standard shipping container’s door height than the 210mm category. The smaller category will also have an easier time with inverters and the current they can handle.

Trina Solar is heading the ‘M12’ group, forming the Photovoltaic Open Innovation Ecological Alliance, which was announced last week and has 39 members from all along China’s photovoltaic supply chain.

Trina also announced the 600 W edition of its Vertex series, which had taken the company up to the 515.8 W mark in April. The company already expected its 500 W modules to enter mass production in Q3, reaching 5 GW production at the end of the year. With the latest announcement, its 550 W series is expected to begin mass production in the fourth quarter. These designs are bifacial Mono PERC with 21.1% efficiency at 210 mm cell size, using multiple busbars, non-destructive triple cutting, and dense packaging.

According to Dr Zhang Yingbin, Trina’s Head of Product Strategy, by expanding on the low-voltage and high-current design seen in the 600 W panel, modules of even 700 W or 800 W could be seen in the future. In the meanwhile Trina’s 600+ W modules are expected to reach 10 GW production capacity this year, followed by 21 GW in 2021 and 31 GW in 2022.

On the other hand, the ‘M10’ group, announced on June 24th, has seven solar companies headed by LONGi, JinkoSolar, and JA Solar, which have recently advocated the standardization of the M10 wafer size at 182mm – it was previously seen at 200mm. These seven companies also called for this 182mm to be treated as the standard for R&D and the industry in general. Like Trina’s 550 W design, these M10 modules can be expected to enter mass production soon. LONGi’s plans see 12 GW by the end of this year, but the M6, 166mm will be the company’s mainstay for a while, with the two sizes coexisting.

This size increase continues a recent trend of increased and varying wafer sizes – breaking the seven-year continuity from 2012 to 2019, in which sizes increased only from 156 mm to 161.7 mm (from M0 category to M4). The introduction of M6, 166 mm wafers began in 2019, most prominently by LONGi. The resulting 72-cells modules weighed 30 kg, approaching the limit for manual installation, while raising operational current to 13 amps – still okay for existing string inverters.

Module size increase brings a big increase in output for a much smaller increase in cost – but manufacturing equipment for processes such as Plasma-enhanced chemical vapor deposition (PECVD), annealing, and diffusion needs to be compatible, and supply chain alterations may briefly push prices up. This causes pressure towards either 182mm or 210mm, now that the more compatible M6 standard has been passed. With these new M10 and M12 sizes, even the physical stability of racking and trackers has to be reconsidered under the increased weight.

It is possible that these high-power modules may contribute to a surge in solar installations in China in the fourth quarter of 2020, which some say will bring the annual total to 45 GW with 20 GW in Q4 alone – a decidedly optimistic prediction we don’t feel is likely.

Tongwei and LONGi are among those which, since April, have adopted lower prices to try to clear out their soon-to-be-outdated capacity. Only recently did prices stabilize, but the long term trend is still downward.

Trina Solar VP Cao Bao commented at Trina’s Vertex product launch on the 16th that due to falling photovoltaic prices, the future possibility of mandatory co-located storage, and close competition between companies, could lead to lower profit margins for the sector, and that accelerated technical improvements are needed for companies to keep up.

This is all in the context that 2020 is the last year in which China’s solar industry will have any level of subsidies – and the end of subsidies is forcing greater cost-effectiveness, and seeing some solar companies fall into insolvency; some consolidation is to be expected, particularly with the pandemic’s temporary depression of demand resulting in oversupply.