Monitoring of lateral moisture ingress across the surface of a solar cell in PV modules

Solution to the two main drawbacks of the already established in-situ humidity ingress monitoring technique using digital humidity sensors in PV modules is proposed. The mechanical impact of the setup laminated in the PV module stack is minimized by using the smallest available sensors SHTW2 from Sensirion, soldered on a thin flexible polyimide based printed circuit board. The new setup can be laminated between solar cell and glass causing no cell or glass breakage and thus enable measurement of moisture ingress along the front surface of the solar cell in the PV module, which was not possible till now. The wired connection has been omitted by applying NFC technology that introduces wireless powering and communication with the laminated sensors. Such a setup can be laminated anywhere in the full size PV module. Both approaches have been tested in different PV module stacks, which have been exposed to elevated temperature and humidity conditions in the climate chamber. Obtained results are consistent with expected moisture ingress behavior, which proves the applicability and usability of the proposed methods.