Interlaminar mechanical performance of a multi-layered photovoltaic-thermoelectric hybrid device

A concentrated photovoltaic-thermoelectric hybrid device made up of a six-layer composite structure is considered. The hybrid device is composed of, from top to bottom, photovoltaic cell, ethylene vinyl acetate (EVA) layer, tedlar polyester tedlar (TPT) layer, ceramic layer, electrode, and thermoelectric legs. Under the service condition, the poor interlaminar mechanical performance of the hybrid device induced by the high interlaminar stresses level can give rise to very poor power generation performance. To understand this, an analytical model is built to study the influence of the thermal contact resistance and interfacial slip stiffness on the interlaminar stresses of the hybrid device. In particular, effects of the material parameters and geometric dimensions of the hybrid device are also studied by using the state space method. It is found that the thermal contact resistance mainly affects the interlaminar stresses of the photovoltaic module. The interlaminar stresses without considering the temperature-dependent material properties are greater than the actual stresses. The highest interlaminar shearing stress appears at the lower surface of the photovoltaic cell and the maximum peeling stress occurs at the interface between the EVA layer and TPT layer. A lower interfacial slip stiffness is conducive to reducing the interlaminar stresses. The interlaminar stresses decrease with decreasing elastic modulus and coefficient of thermal expansion of the EVA layer. In addition, a thinner thermoelectric layer contributes to lower the interlaminar stresses. The results offer helpful suggestions for the optimization of the interlaminar mechanical performance of the hybrid device.