Effect of novel encapsulants and backsheets on short circuit current in interdigitated Back contact solar cells based PV modules

Abstract

Due to zero shading and higher packing density, interdigitated back contact (IBC) solar cells based PV modules offer low optical losses as compared to conventional PV modules. The optical losses in PV modules are mainly governed by reflection losses. In this work, loss in short circuit current density (JSC) due to reflection losses from two types of coupons, (1) back contact solar cell having glass-glass packaging with Aluminium foil as back sheet (2) back contact solar cell with conventional Tedlar as back sheet, are evaluated by incorporating two novel encapsulants, thermoplastic polyolefin (TPO) and polybutadiene ionomer (PBI), along with conventionally used ethylene vinyl acetate (EVA). The loss in JSC in case of “(1)” with TPO, PBI and EVA are found as 3.043 mA/cm2, 3.048 mA/cm2 and 3.11 mA/cm2 respectively. While, the loss in JSC in case of “(2)” with TPO, PBI and EVA are found as 2.88 mA/cm2, 2.95 mA/cm2 and 3.024 mA/cm2 respectively. Although lesser losses are observed in case of Tedlar based coupons, the results obtained from Aluminum foil based coupons are still very much comparable and its lower cost makes it a good choice to replace Tedlar in future. Moreover, the results clearly showed that TPO and PBI performs better as compared to conventional EVA with an added advantage of being less prone to encapsulant discoloration.