New technologies, new opportunities – pv magazine France

UK analyst Exawatt and Germany’s Nexwafe released a white paper this week that takes a close look at the current state of PV manufacturing around the world and how Nexwafe’s innovative wafer production technology could fit into it. They said if the potential of its Epiwafer could be realized, the PV industry could yet see “another revolution in wafer manufacturing”.

A white paper published this week by British analysts Exawatt and German Nexwafe analyzes the current state of PV manufacturing. The study reveals opportunities and challenges for new technologies, in particular Nexwafe’s innovative “Epiwafer” process for the production of silicon wafers.

Nexwafe’s technology eliminates the steps of polysilicon production and ingot mining, replacing them with a process that grows wafers directly from silicon tetrachloride gas, or the trichlorosilane gas that is used today as raw material for the production of polysilicon. By removing these cumbersome industrial steps from the photovoltaic supply chain, the process promises lower manufacturing costs, reduced capital expenditure and reduced environmental impacts, as well as thinner and potentially higher quality wafers capable of achieving higher yields when transformed into cells.

The white paper, available for download from Nexwafe’s website, seeks to place this technology in context with the current photovoltaic manufacturing landscape and assess its potential. Nexwafe is developing a 500MW demonstration line for its technology in Germany and last year raised 39 million euros ($42.5 million) in an Indian-led investment round. Reliance Industries. Despite these successes, the technology still has some way to go to prove itself at scale.

Technical advantage

Exawatt sees a significant opportunity for this new technology to leverage other developments in PV manufacturing. And it is capable of producing wafers of any size, avoiding the problems reported when mining ingots for the largest 210mm format.

The process also allows for the manufacture of much thinner slices than current ingot/diamond wire saw processing allows. Nexwafe CEO Davor Sutija recently said photo magazine that the company would most likely produce its first wafers at 120 microns, and could become much thinner than that later, if manufacturers are able to improve handling of thinner, more fragile products at other stages . Exawatt notes that this would provide an advantage or heterojunction cells in particular, where the optimal thickness is 100 microns or even less, whereas PERC and TOPCon structures work best on a cell between 150 and 200 microns, as can be performed using current methods.

Nexwafe’s process also promises lower oxygen content and even dopant distribution, representing up to 1.1% absolute efficiency gains, while opening up new possibilities. “In the longer term, the high level of process control offered by the EpiWafer process could allow the use of additional techniques to further increase cell efficiency, for example through the incorporation of quantum dots,” says Exawatt. .

Market opportunity

The recent push for energy security and localized PV supply chains also creates an opportunity for regions outside of China to produce differentiated generation, rather than trying to compete at scale with PV giants. established industry. Exawatt notes that Nexwafe has signed letters of intent with several of the major players looking to establish PV manufacturing outside of China, alongside Reliance’s investment in India.

Most important remains the ‘lab to factory’ scale-up, with Exawatt warning that the initial 500MW installation in Germany will not be competitive with current wafer prices, although this model is starting to sell. improve once Nexwafe reaches larger capacities of 3 GW and then 6 GW.

“From a financial perspective, the main challenge will be to successfully scale and bridge the gap between lab-scale and high-volume production. From a technical perspective, it will be essential to demonstrate that the theoretical increases in cell efficiency offered by EpiWafers can be realized in practice in cell manufacturing,” the report concludes. If this potential can be realized, the photovoltaic industry could see yet another revolution. in the manufacture of wafers.

This content is copyrighted and may not be reused. If you wish to cooperate with us and wish to reuse some of our content, please contact: [email protected]