Reliability-based structural optimization of 300 × 300 mm2 dye-sensitized solar cell module

Dye-sensitized solar cell (DSC) is a promising candidate for the application in building-integrated photovoltaics (BIPV). At higher temperature above 85 °C, the reliability of the module has remained a major challenge yet. A large DSC module, sized 300 × 300 mm2, is developed. In the preliminary module design, the width of cell is 11 mm and the coefficients of temperature expansion (CTE) for sealant and electrolyte are 699 and 807 ppm/°C, respectively. The modules are stored in 85 °C. The power conversion efficiency of the modules drops rapidly in 100 h during the test. To analyze and enhance the module design in view of reliability, finite element model is developed for the module. Stress analysis reveals that high stresses in electrode cause the breakage of electrode and sealant in succession and the loss of electrolyte finally. From a parameter sensitivity analysis with the finite element model, it is identified that the maximum stress in electrode can decrease when the cell width increases. CTEs of sealant and electrolyte can be also optimized as analysis confirms that the maximum stress in electrode drops when the CTEs of sealant and electrolyte decrease. Based on the studies, new module design is formulated, which have the cell width of 18 mm and the CTEs of 277 and 656 ppm/°C for sealant and electrolyte, respectively. The new modules are tested in 85 °C and show much better lifetime than the preliminary one without the leakage of electrolyte.