Longi serves up powerful new rooftop solar module, heralds “arrival of BC era”

Chinese solar manufacturer Longi has unveiled a new module designed for the rooftop PV sector, boasting 24.8 per cent efficiency and the ability for current to bypass shaded or hotspot-affected areas of the panel.

Unveiled at the Rolex Shanghai Masters tennis tournament in China, the new Hi-MO X10 features HPBC 2.0 cell technology and utilises TaiRay silicon wafers to deliver a maximum mass production power of 670W, surpassing mainstream TOPCon modules by over 30W.

And, with a maximum module efficiency of 24.8 per cent, Longi boasts that their new Hi-MO X10 represents the last generation of crystalline silicon cells to achieve an absolute efficiency leap of 1 per cent. “signalling the true arrival of the BC era.”

BC refers to the back-contact cell technology the company introduced into its line-up late 2022, which significantly amplifies sunlight absorption.

“We firmly believe that BC technology will become the dominant force in crystalline silicon cells, including both bifacial and monofacial designs,” said Zhong Baoshen, Longi chairman.

“In the future, a significant portion of LONGi’s product lineup will embrace the BC technology pathway. Our mission is to promote this widely recognized technology platform, which offers high compatibility and excellent weatherability, across a wider range of applications and markets.”

Longi claims that their HPBC 2.0 cells have a maximum production conversion efficiency of 26.6 per cent, building on the first generation HPBC 1.0 cells.

The new Hi-MO X10 modules also include the company’s self-developed Bipolar Hybrid Passivation technology which allows the mass-produced cell open-circuit voltage to exceed 745 mV, beating out the industry’s mainstream TOPCon products by 15mV and, subsequently, significantly reducing current loss and improving cell conversion efficiency.

The Hi-MO X10 also features an HPBC 2.0 cell that adopts an innovative 0BB structure which is completely free of grid lines on the front and busbars on the back, allowing module power to increase by around 5W.

Maybe most importantly, the new Hi-MO X10 modules also feature what Longi describes as a unique “soft breakdown design” which allows current blocked by shading or hotspots to bypass those affected areas, redirecting it through alternative internal pathways within the cell, helping to reduce power loss by over 70 per cent compared to TOPCon modules.

“This design not only minimizes power loss and maximizes energy generation efficiency by effectively rerouting the current, but also lowers hotspot temperatures by 28%, ensuring stable operation and rooftop safety,” Longi said.

The modules have also been designed to withstand increasingly extreme weather events over a 25- to 30-year lifespan. The Hi-MO X10 modules feature a low operating temperature and high-density encapsulation, offering comprehensive anti-aging properties and performing well under rigorous testing.

Longi claims that their new modules exhibit “superior resistance to UV, damp heat, and thermal cycling, making it more resistant to heat, moisture and prolonged exposure to the sun” and boasts a temperature coefficient of -0.26%/℃, delivering a first-year degradation rate of 1% and linear degradation of 0.35%, providing customers with a 15-year product warranty and a 30-year power warranty.