CubicPV Wafer Production To Fill Gap In US Solar Supply Chain

According to the report, the data does not point to a single degradation mechanism, but rather suggests that different cell designs degrade via different pathways.

CubicPV Wafer Production To Fill Gap In US Solar Supply Chain

The PV Module Index 2022 from the Renewable Energy Test Center (RETC) tracks the latest trends in solar module quality, performance, reliability, and emerging technologies. TOPCon solar modules, first demonstrated at the Fraunhofer Institute for Solar Energy Systems in 2013, is now gaining market traction and acceptance.

The system is made up of n-type PV cells with passivating contacts. The modules have a high open-circuit voltage and a high efficiency due to their strong surface passivation and effective carrier transport. TOPCon is being used as p-type passivated emitter and rear-contact cell (PERC) modules approach their theoretical efficiency limits.

RETC noted that this increase in efficiency has made TOPCon “the buzziest word in solar.” While Longi Solar is “betting big” on p-type TOPCon, many other leading module companies, including Jinko Solar, Jollywood Solar Technology, JA Solar, and Trina Solar, are investing heavily in modules with n-type TOPCon cell designs, according to the report.

“You can achieve higher efficiencies and power ratings by using higher open-circuit voltage values.” That, in and of itself, is likely to push manufacturers towards n-type TOPCon cell designs as soon as they can,” said Kenneth Sauer, principal engineer, VDE Americas.

According to RETC, high-efficiency n-type cells using heterojunction technology (HJT) and interdigitated back contact (IBC) cells are relatively expensive to produce and remain a niche part of the market due to manufacturing complexities. In comparison, n-type TOPCon cell production is very similar to PERC cell production, making the transition from existing manufacturing lines easier.

“While today’s n-type TOPCon modules are slightly more expensive to produce per watt than p-type mono PERC modules, the efficiency gains result in a lower levelized cost of energy (LCOE) in large-scale field deployments.”

“Best of all, leading experts anticipate that n-type TOPCon will benefit from an accelerated learning curve,” according to the report. However, the report warns that, as with any emerging technology, moving towards TOPCon may be risky.

While n-type TOPCon PV cells have proven resistant to light-induced degradation and light and elevated temperature-induced degradation, there is some evidence of UVID susceptibility, which could reduce module longevity.

Front- and back-side power loss from these technologies has been documented by researchers at the SLAC National Accelerator Laboratory and the National Renewable Energy Laboratory (NREL).

According to the report, the data does not point to a single degradation mechanism, but rather suggests that different cell designs degrade via different pathways. “We’re not trying to raise the alarm for no reason,” said Cherif Kedir, CEO of RETC.

“All we want to do is test the potential for UV degradation in order to educate ourselves and the industry.” If there is no problem, we can all go about our lives.”

As part of a technical due diligence survey, Kedir recommends that module makers conduct accelerated UVID testing. Cell passivation layers that are not properly tuned may fail under this exposure. He advises evaluating each new cell design on an individual basis. “If there is a problem, we will publish a report so that the industry can get ahead of the problem,” he explained.