Direct detection of vibration and resonance of the solar cells in vehicle-integrated photovoltaic modules

Photovoltaic (PV) modules are crucial power sources for automobiles. The fragility of solar cells and frequent vibrations and impacts experienced by car bodies pose significant risks to the reliability of vehicle-integrated photovoltaics (VIPV). Standard PV module designs use soft resins, such as Ethylen-Vinyl Acetate (EVA), to dampen vibrations; however, these materials are ineffective at the higher vibration frequencies encountered in in-vehicle applications. This study employed a laser Doppler vibrometer (LDV) to nondestructively detect cell vibrations and confirm the resonant frequency of solar cells in VIPV modules. This research aims to determine whether the LDV method can detect the independent vibration motion of a solar cell if the solar cells resonate independently within the module, and whether the resonance frequency is close to the natural resonant frequency of the structure. This study also explored the potential of designing resonance-resistant VIPV modules. These findings indicate that the LDV can detect the resonance of solar cells within the vibration frequency range of car roofs. Owing to the low damping factors, the solar cells vibrate independently of the glass cover, with the vibration energy at resonance reaching up to 20 times the normal level. This mechanical resonance poses a substantial threat to the reliability of the VIPV. The study concluded that while eliminating the source of vibration is impractical, making the structure less susceptible to vibration through design modifications is a viable solution, increasing the natural resonance frequency above 2000 Hz.