Global solar markets are moving towards high efficiency, powerful, large sized modules incorporating latest cell technologies with manufacturers claiming their products to be future-ready and cost-competitive. Increasing demand for solar PV ensures modules are constantly rolling off the factories whose number and annual capacities increase by the day.
As TaiyangNews Managing Director Michael Schmela put it in his welcome note, module reliability should be on top of the list for all industry stakeholders since eventually a long serving, efficient module is what everyone desires. To assess the 'what' and 'how' of this aspect, TaiyangNews brought together a group of experts and industry leaders for our Reliable PV Module Design Virtual Conference—How To Make High-Quality Solar Modules.
Presenting initial findings of our Market Survey on Backsheet and Encapsulation Materials 2022, TaiyangNews Head of Technology Shravan Chunduri pointed out that CPC is now the leading configuration of backsheets as fluoropolymers rule the market. Backsheets, though popular, have a new competitor in the form of glass. For heterojunction (HJT), it is EPE, for TOPCon POE is the most followed solutions currently.
VP Sales and Marketing at PV Evolution Labs (PVEL), Tristian Erion-Lorico talked about solar module reliability testing. He said while modules vary in their use of technology and materials meaning they are not equal, extensive testing can predict fielded module reliability especially in times of high-volume manufacturing and technological changes. There is no need to be afraid of new technologies, but 'do your due diligence.'
Presenting an analysis behind factors responsible for backsheet failures, Fraunhofer ISE's Head of Team Module Analytics Dr. Paul Gebhardt said current standard testing is not enough to ensure consistent high quality for entire lifecycle of solar modules. The industry needs better standards to avoid failures and provide good economics to customers and installers alike.
LONGi's Senior Product Manager Dongxia Ni shared the company's strategy to look at solar modules from a complete lifecycle angle, and provide a very comprehensive view at the topic. For the leading vertically integrated Chinese module manufacturer, lifecycle of the modules starts from the design stage and goes on till after-sales service. The company, which is a RE100 member, among others, said 40.19% of its energy consumption in 2021 was renewable.
JA Solar's Senior Product Promotion Manager Jerry Sun listed encapsulation material, thinner ribbon and new structure encapsulation material among factors affecting the reliability of high-power modules. He said TOPCon module reliability has been improved with new encapsulation structure EPE, maintaining the POE film thickness at 150 microns and adapting thinner ribbons.
While discussing the leading backsheet structures and their apt applications, the world's leading backsheet producer Jolywood said any organic material used for backsheets will lead to toxic and harmful derivatives after burning. A non-fluorine based backsheet will reduce reliability. Hence, these should be made using fluorochemicals. To ensure safety and reliability. Jolywood is now also offering transparent backsheets with and without grid.
Zhang also shared that currently more than 90% of 220 GW global backsheet production capacity exists in China, with more than 80% raw material coming from the Asian giant. The growing market for backsheets is also facing challenges in terms of rising raw material price. Even as there is surplus laminating backsheet capacity, there is a shortage of coating backsheet capacity at present.
HiUV's Senior Marketing Manager Peter Peng spoke about the reliability of TOPCon and HJT module secured by innovated encapsulation solutions from the company. He sees pure POE as a reliable solution for n-TOPCon module at current stage, yet there is still scope for improvement. Its encapsulant film solution for TOPCon technology called EXP reduces POE resin consumption, meets module reliability compared with pure POE and is flexible enough to produce low gram film. For HJT, HiUV is also producing UV light conversion films. HiUV strives to reach around 100 GW production capacity by year end.
Speaking about innovations in module encapsulations—polymer solutions for advanced cell technologies, Cybrid's Senior Product Manager Stephen Gong sees non-fluorine backsheet solution in the future to be majorly transparent with black reflection. For HJT, Gong recommended using a light conversion type as EPE or EVA, while for TOPCon it needs to be POE+POE or EPE+EVA for glass-glass and for glass-backsheet, it should be POE+EVA or POE+white EVA.
Gong argued that transparent backsheets must be required to pass sequential reliability testa.
Batting for high-quality POE over EVA, Dow Chemical's PV Application Technical Leader Yuyan Li presented the company's ENGAGE PV POE based encapsulant solutions for high efficiency bifacial modules.
According to Li, EVA film doesn't offer strict water resistance required for PERC bifacial modules with transparent backsheet, but emphasized the company's ENGAGE PV POE offers 'excellent' PID resistance. The latter also brings down gram weight and cost by 8.2% when compared with PV grade EVA. Presently, Dow's ENGAGE annual production capacity is 1.2 million tons globally.
Executive Panel
Moderated by TaiyangNews' Shravan Chunduri, the executive panel deliberated on measures to ensure reliability for modules with high efficiency cell architectures.
According to PVEL's Tristan Erion-Lorico, if the modules offer high reliability and are built to last 40 or 50 years, it would mean we need to make less number of modules and we don't have to recycle more modules either. This should contribute directly to lowering carbon footprint of the PV industry. Hence reliability should be a top priority for module manufacturers.
JA Solar's Jerry Sun feels there should be more talk about recyclability aspect as it would encourage manufacturers to design their products with the end in sight.
HiUV's Peter Peng stressed that to make a high-quality product using new age cell architectures as TOPCon and HJT, focus should be on making these products reliable so the future installations are long-lasting.
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