LONGi launches light-weight back contact module for C&I rooftops with load limits

LONGi has launched 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 LONGi’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 560 W, reaching a power density of 250 W per square meter. The total module weight is 16.3 kg, or 7.2 kg per square meter, making it approximately 30% lighter than conventional single-glass modules. This reduction enables installation on aging or lightweight rooftops without additional structural reinforcement, significantly lowering balance of system (BOS) costs per watt. The optimized frame and one-line welding structure on the rear enhance 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 includes weak conduction features that reduce overheating and hotspot risk, while allowing shaded cells to recover up to 70 percent more power than standard modules. A 30 g thicker encapsulation film further improves resistance to moisture and UV exposure. The module will be available in 60-cell format (1990 × 1134 × 30 mm) and is compatible with standard A-side clamp mounting systems. By eliminating 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 prioritize reliability. The new Hi-MO X10 Light Design module is a clear reflection of that principle.”

30% lighter than standard modules, designed for structural constraints

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 16.3 kg, the Hi-MO X10 Light module significantly reduces rooftop load and is suitable for aging or lightweight buildings. On a 10,000 m² rooftop, this weight reduction translates into approximately 34 tons of avoided structural load. Despite the lower weight, the module maintains high mechanical stability through its one-line welding ribbon on the rear side as well as 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 optimized frame, the module withstands front loads of up to 3600 Pa and rear loads of 2400 Pa, equivalent to 2 to 3 meters of snow or grade 12 wind conditions. Frame strength is further enhanced with a 5 percent thickness increase, resulting in 20 percent higher mechanical resistance and 50 percent lower central deformation under stress.

Stronger long-term durability than conventional flexible modules

Unlike most flexible modules on the market, which typically 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 1.6 mm semi-tempered front glass and reinforced frame avoid common reliability issues such as yellowing, deformation, or microcracks. The module’s rear film weighs 50 g/m² more than standard products, enhancing 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.”

Standard installation method shortens timelines and avoids operational disruptions

The Hi-MO X10 Guardian Light Design module uses the same A-side clamp installation method as conventional modules, requiring no special tools or training. This simplifies deployment and reduces labor effort. Compared to systems that require rooftop reinforcement, project timelines can be shortened by up to 34 days. Even when compared to other lightweight products, installation is around 10 days faster. For industrial facilities where continuous operation is critical, the ability to install without structural modification helps avoid costly production downtime and accelerates return on investment.

Higher output per square meter lowers BOS costs and increases project value

The module’s output of up to 560 W and efficiency of 24.8% enables high energy yields even on area-constrained rooftops. Power density reaches 250 W per square meter. Compared to other lightweight modules, each unit provides approximately 140 W more power, enabling larger system capacity on the same surface area. This reduces balance of system (BOS) costs per watt by about 33 percent.

Installing conventional solar modules on low-load-bearing roofs often necessitates structural reinforcement, adding approximately €0.18 to €0.20 per watt to the total project cost. For a typical 1 MW commercial installation, this equates to €180,000 to €200,000 in additional expenditure. With the Hi-MO X10 Guardian Light Design, no reinforcement is needed, enabling the system to start generating revenue sooner. 

HPBC 2.0 platform enhances safety and energy yield under real-world conditions

The module is built on LONGi’s HPBC 2.0 cell architecture, which includes a weak conduction design to reduce local overheating during shading. This lowers hotspot-related temperature by 28 percent compared to conventional cells and allows shaded cells to recover 70 percent more power than standard modules. Back contact welding reduces edge stress and cracking risk significantly. In empirical testing, the surface temperature of the HPBC 2.0 module was significantly lower than that of comparable TOPCon modules under identical partial shading conditions. Field tests show that under identical leaf-shading conditions, the Hi-MO X10 Light Design module reaches local hotspot temperatures of around 80°C. These are significantly lower than those typically recorded in conventional TOPCon modules, substantially reducing fire risk.

The use of TaiRay silicon wafers further increases mechanical strength by 16 percent, and a 0BB cell structure boosts compression resistance by 23 percent. The module also uses an advanced encapsulation process with an adhesive film that is 30 g thicker than conventional modules, enhancing resistance to water vapor intrusion and prolonged UV exposure.

The module is available for order in Europe in August 2025.

Link to datasheet: https://short.longi.com/Guardian-LR7-60HVHL

Link to dedicated webpage: eu.longi.com/hi-mo-x10-guardian-light-design