Lightweight back contact module for rooftops with load limits

LONGi has released the Hi-MO X10 Guardian Light Design module, a lightweight back contact solar solution for commercial and industrial rooftops with limited structural load capacity. Built on the company's HPBC 2.0 (Hybrid Passivated Back Contact) cell technology, the module delivers a mass production efficiency of 24.8% and a maximum output of 560W, reaching a power density of 250W per square metre. The total module weight is 16.3kg, or 7.2kg per square metre, making it approximately 30% lighter than traditional single-glass modules. This reduction allows installation on ageing or lightweight rooftops without further structural reinforcement, greatly lowering balance of system (BOS) costs per watt. The optimised frame and one-line welding structure on the rear improve durability under pressure loads of up to 3,600 Pa on the front and 2,400 Pa on the rear, equivalent to heavy snow and strong wind conditions. To support long-term reliability, the HPBC 2.0 cell design incorporates weak conduction features that lower overheating and hotspot risk, while permitting shaded cells to recover up to 70% more power than standard modules. A 30g thicker encapsulation film further improves resistance to moisture and UV exposure. The module will be available in 60-cell format (1990mm × 1134mm × 30mm) and is compatible with standard A-side clamp mounting systems. By removing the need for structural reinforcement, it shortens installation timelines and avoids disruptions to ongoing operations.

"Even in an industry increasingly focused on cost reduction, we remain committed to our core values of stability, reliability, and technological leadership," said Jiang Dongyu, global president of LONGi's Distributed Business Group. "When cost and reliability come into conflict, LONGi will always prioritise reliability. The new Hi-MO X10 Light Design module is a clear reflection of that principle."

The Hi-MO X10 Guardian Light Design is particularly suited for commercial buildings with structural limitations, including older industrial facilities, warehouses, and buildings with thin-sheet roofs. It opens opportunities for solar where traditional modules would require costly or impractical reinforcement measures. A growing number of existing facilities globally, estimated to exceed one billion square meters, could become solar-viable using lightweight module technology.

With its 16.3kg, the module greatly reduces rooftop load and is suitable for ageing or lightweight buildings. On a 10,000m² rooftop, this weight reduction translates into approximately 34 tons of avoided structural load. Despite its lower weight, the module maintains high mechanical stability thanks to its one-line welding ribbon on the rear side and the I-shaped reinforcement ribs on the back. It creates efficient mechanical distribution, avoids the risk of stress concentration, and improves bending and torsion resistance. Together with an optimised frame, the module withstands front loads of up to 3600 Pa and rear loads of 2400 Pa, equivalent to 2m to 3m of snow or grade 12 wind conditions. Frame strength is further enhanced with a 5% thickness increase, resulting in 20% higher mechanical resistance and 50% lower central deformation under stress.

Unlike most flexible modules on the market, which generally rely on lower-efficiency technologies such as PERC or TOPCon, the Hi-MO X10 Light Design Module combines high-efficiency back contact technology with robust mechanical strength and long-term electrical performance. Its 1.6mm semi-tempered front glass and reinforced frame avoid common reliability issues such as yellowing, deformation, or microcracks. The module's rear film weighs 50g/m² more than standard products, improving moisture sealing and heat resistance. It also avoids adhesive-based mounting, which is prone to long-term detachment and maintenance challenges.

"The launch of the Hi-MO X10 Light Design module addresses a critical challenge in the low-load rooftop segment and marks another step in LONGi's scenario-based, differentiated product strategy," said Jia Chao, president of LONGi Europe for DG. "We will continue to drive dual innovation in both technology and product development to deliver tailored solutions that meet the diverse needs of global energy markets."