Evaluation of the PID-s Susceptibility of Modules Encapsulated in Materials of Varying Resistivity

A common mechanism of potential-induced degradation is by shunting (PID-s) in PV modules, usually associated with the transport of sodium ions (Na+ through the encapsulant and penetrating the front junction of solar cells under voltage stress. Encapsulants with high volume resistivity have been suggested as a potentially cost-effective solution to this degradation mechanism. In this work, we examine three polyolefin elastomer (POE) encapsulants with volume resistivity varying over two orders of magnitude (ranging from 9 \times 10 131 \times 10 16 )85 {circ}\mathrm {C}85% 1000 ()1 \times 10 13 cm. The independence of PID susceptibility with respect to the resistivity of the polyolefin is attributed to the impermeability of POEs to Na + ions. Specific ions (i.e., Na +), rather than charge-carrying species in general, are responsible for this degradation mechanism.