Triple-Junction Concentrator Photovoltaic-Thermoelectric Hybrid Receivers: Robustness, Validation and Preliminary Reliability Studies

摘要

Multi-junction photovoltaic cells utilise the incident solar spectrum effectively with photon to cell efficiencies of up to 46% recently achieved for a wafer-bonded four-junction cell [1]. However even industry standard designs, such as monolithic lattice matched triple junction architectures, have high manufacturing costs. Optical concentration is an effective way of combining this technology with comparatively low-cost lenses to increase the incident light flux on the cell, achieving competitive parity cost per Watt with cell efficiencies over 50% [2], or in conditions with greater than 1500Wm~(-2) irradiance [3]. Thermoelectrics (TE) are solid state semiconductor devices that can either exploit a temperature differential to generate power (Bi_2Te_3 thermal to electrical conversion efficiency =～ 1% at 25°C ΔT)[4], or inversely use electrical power to act as a heat pump (typical Coefficient Of Performance of Bi_2Te_3 =～1 at 25°C ΔT) [4]. One of the barriers for large-scale deployment of Concentrator Photovoltaic (CPV) technology for energy generation is its technology legacy. Silicon based panels have had many years of performance and lifetime data and investment risk is low. Recent publications show an evolving trend of hybrid solar devices being evaluated, including that of CPV-TE monolithic devices. Optimisation and simulation studies are prevalent [5-10], but experimental data is sparse especially for triple junction solar cells [11, 12]. Experimental characterisation and reliability testing of CPV-TE hybrids are investigated in this paper.