Exeo Group has begun demonstration testing of a grid-independent solar carport system designed to maximize solar energy utilization. The system uses a combination of semiconductor circuit breakers and a lithium-ion battery eliminating the need for a traditional inverter (PCS) to manage power conversion and storage.

The demonstration facility features a 10 kW crystalline silicon PV array installed on the carport, a 375 V / 72 kWh lithium-ion battery, and two 10 kW rapid EV (Electric Vehicle) chargers. The carport is designed to accommodate not only standard EVs but also two 2-ton vehicles, such as electric bucket trucks and commercial trucks.

The PCS-free system integrates multiple semiconductor circuit breakers and sensors to optimize solar power generation, manage battery charge and discharge cycles, and ensure a high level of operational safety. Since the system operates completely off-grid, a full discharge of the lithium-ion battery would result in a loss of control power. To address this, a compact backup power supply is incorporated into the control unit, powered by a next-generation nickel-zinc battery developed by FDK Corporation. This battery offers compatibility with lead-acid systems, while providing reduced weight, lower environmental impact, and ease of use with lithium-ion charging infrastructure. The performance of this backup system is also under evaluation.

Unlike conventional solar carports which connect to the utility grid via a PCS and require substantial civil and electrical infrastructure—the grid-free system charges a nearby lithium-ion battery directly from solar power. EVs are then charged from this battery. By removing PCS losses, the system is expected to provide up to 1.4 times more usable energy per day compared to traditional setups. Although a larger battery is needed for stable EV charging, the ongoing drop in lithium-ion battery costs is expected to offset this, delivering long-term economic advantages. Most notably, the system enables 100% local consumption of renewable energy, promoting truly sustainable EV usage.

The system’s core control technology is based on collaborative research with Kyoto Institute of Technology and Nagasaki Institute of Applied Science.

Exeo is also exploring next-generation solar carport designs using membrane roof structures. In collaboration with Taiyo Kogyo Corporation, the company has tested the adhesion and durability of flexible, silicon-based PV modules applied to PVC-coated fiberglass membrane. These lightweight, flexible modules offer promising potential for architecturally adaptable solar roofing. Durability assessments are ongoing using a full-scale mock-up of the proposed roofing structure.

Exeo will continue evaluating system performance, including seasonal solar variation, EV usage patterns, and optimization of battery and PV capacity. Future development plans also include testing perovskite-based flexible PV modules, further advancing the integration of cutting-edge materials with real-world EV charging infrastructure.