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14 December 2022

Meyer Burger gathers perovskite group in quest for 30%+ tandem

Germany’s Meyer Burger has put together a consortium to build and continuously improve perovskite tandem PV cells, and has moved on from its legal spat with Oxford PV, which was its initial preferred partner in perovskite.

When the two split 18 months ago, there were fears that Meyer Burger sitting on the board as a large minority shareholder, was planning to usurp Oxford PV’s global lead in perovskite PV technology – a fear that has turned out to be correct. When asked to comment this week Oxford PV refused to speak to Rethink Energy.

After numerous denials and a legal stand-off, with Meyer Burger initially feigning a lack of interest in perovskites, the company has suddenly put together another team which will target the introduction of a perovskite silicon two terminal tandem in the near future. The specification looks identical to those suggested by Oxford PV – 27% efficiency immediately, with a further 1% efficiency added every year until it reaches its theoretical maximum at around 37% of the energy landing on a solar panel.

Meyer Burger has partnered with chip innovator CSEM from Switzerland, and solar materials group Helmholtz-Zentrum Berlin (HZB), along with the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, and the Institute of Photovoltaics at the University of Stuttgart. This grouping is now working on the industrialization of perovskite tandem technology,

which the company says is expected to allow the industrial production of solar cells with efficiencies in excess of 30%. However it gives no likely timeframe for this to result in a product, and simply says “in the future.”

Critical to this process will be a working heterojunction technology such as the proprietary Meyer Burger system which it was supposed to be working on with Oxford PV back in 2019.

The statement continues, “This includes the essential manufacturing processes and machinery for silicon-based perovskite tandem solar cells, as well as corresponding solar modules with Meyer Burger’s proprietary SmartWire connection technology.”

Meyer Burger also acknowledges its past work with Oxford PV saying, “The work with the new consortium is based on existing collaborations for the development of heterojunction silicon solar cells. In the past, Meyer Burger entered into collaborations to research perovskite technology, including with Oxford PV, and has therefore already developed its own proprietary technological solutions. Perovskite technology represents a key milestone on Meyer Burger’s innovation roadmap.” Seems like Meyer Burger was researching perovskite in the background all the time, without telling Oxford PV, and potentially relying on Oxford’s intellectual property.

Interestingly Italy’s leading utility ENEL said two week ago at its capital markets day that it also plans to bring this type of technology to the table with its own manufacturing plant, starting at 3GW and rising to 6GW in Europe, with a mirror image plant in the US taking its global output to 12 GW, specifically talking about modules which exceed 30% efficiency. The world record for fully formed solar modules is currently around 27% and they are very expensive.

ENEL said it would upgrade its Sicily 3Sun Gigafactory from 200 MW to 3GW creating 1,000 jobs ushing an advanced HJT technology – our first thoughts were that ENEL may have partnered with someone like Oxford PV. But now it might well be Meyer Burger, which after all has always had a technology sharing agreement with Oxford PV, which it may believe protects it from IPR license issues with Oxford PV.

Meyer Burger was always planning to leverage Oxford PV’s 5 years lead in perovskite research, to get into the technology, but when its management team changed and the company changed direction from an equipment provider to a module maker in 2020, it raised suspicions among the Oxford PV board that Meyer Burger was about to become a rival. It turns out they were right to worry. Meyer Burger will have exclusive rights to whatever comes from this design co-operation.

The change in direction at Meyer Burger, leaving the equipment supply business behind to focus on becoming a top end supplier of heterojunction cells, happened because of the huge concentration of its equipment customers in China, and the possibility of China supplying its own heterojunction designs. Now with the emerging mantra for energy in Europe being energy security, Meyer Burger has been able to raise €253 million in November to ramp its SmartWire modules to 3GW of production at its Thalheim, Germany site and its mirror site at Goodyear, Arizona.

Meyer Burger as far as we know still owns 19.76% of Oxford PV, which it paid for with stock of its own, which are held by Oxford PV. At the time we believe that Oxford PV sold some of this stock to part pay for help setting up a tandem silicon-perovskite production line in Germany – which was never completed as Meyer Burger withdrew its support after Oxford PV fired the board member and withdrew co-operation on the technology sharing deal.

While Oxford PV has been circumspect ever since this deal, and has not issued any statements about getting a new heterojunction technology provider to continue the build out of its production line, clearly Meyer Burger sees no reason not to bring its desire for tandem technology out into the open.

The principle of tandem technology is to have two separate layers with different PV properties each absorbing different parts of the spectrum, and then re-combining the energy generated within the module. Simpler formats called four terminal systems, whereby there are two separate circuits coming from the two layers, are already hitting the market using perovskite, notably from Caelux in California, set to begin sales in early 2024. Other Tandem efforts are being pioneered by French solar manufacturer Voltec, which says it will have a pilot line in 2023.

CSEM and Meyer Burger say they have achieved a record efficiency of 29.6% for a 25-square-centimeter perovskite tandem solar cell already using heterojunction silicon cells with perovskite structures, while HZB says it has achieved over 31% efficiency in the lab for heterojunction with perovskite.

Back in 2020 Oxford PV was thought to have a 3 to 5 year lead on manufacturing tandem silicon perovskite cells, but at the same time Meyer Burger was considered to have considerable skills in producing heterojunction solar, with the Fraunhofer Institute saying publicly it had tested the Meyer Burger process and found it to be “at least three years ahead of competitors and ready for market.”