In situ quantification of temperature and strain within photovoltaic modules through optical sensing

The ability to quantify internal strain levels within a photovoltaic (PV) laminate is essential to aid in the development of reliable and sustainable PV modules. This need is even greater for emerging applications with a high degree of integration such as vehicle and infrastructure integrated PV. Within this work, we demonstrate a scalable optical sensing solution, which allows for the in situ thermo‐mechanical strain and temperature monitoring of photovoltaic modules. Using a combination of two optic fibers with fiber Bragg gratings (FBGs) with a different packaging, an absolute in‐laminate temperature accuracy of ± 0.3°C has been achieved along with the ability to detect changes in strain as low as ± 0.248 μϵ. The sensor solution provides the potential to monitor and quantify various failure modes or degradation at various stages in the development process up to in‐field monitoring. Furthermore, it provides a platform for the direct validation of physics‐based simulations. Within this work, a novel approach to in‐laminate sensing is proposed and demonstrated employing optical sensors using Fibre Bragg Gratings. This scalable approach enables in situ monitoring of the thermo‐mechanical behavior of many laminate constituents during all development phases ranging from production up to field testing. Using an optically transparent packaging, an absolute temperature accuracy of ± 0.3°C and a strain sensitivity lower than 0.248 μϵ has been achieved. To demonstrate the potential of this approach, a case study on thermal cycling conditions is discussed.