Development of Encapsulant-Less Crystalline Silicon Photovoltaic Modules and Their Durability Against Potential-Induced Degradation

Conventional crystalline silicon (c-Si) photovoltaic (PV) modules show degradations related to encapsulant, and are difficult to disassemble into individual components. To overcome these issues, we develop a novel crystalline silicon (c-Si) photovoltaic module with openable cover glass. Cells in the modules are not fixed but are just put on hollows in a plastic base. We also investigated the PID tolerance of such encapsulant-less PV modules. In the modules with n-type front-emitter cells, the encapsulant-less modules show significantly high tolerance against polarization-type PID (PID-p). Furthermore, in the modules with p-type Al-BSF cells, shunting-type PID (PID-s) can also be effectively suppressed. We observed that slight PID-s occurs when the cells are in touch with cover glass, and a sufficient gap is necessary between them. An issue for this type of encapsulant-less modules is water ingress, leading to precipitate formation. To suppress water ingress, the development of encapsulant-less modules with O-ring is ongoing.