SPLTRAK Abstract Submission
Towards a Shade Tolerant Monolithically Interconnected Perovskite Module for use in Four Terminal Tandem Devices
Klaas Bakker1, Jacopo Sala2, Mehrdad Najafi1, MichaŽl Daenen2, Bart Geerligs3
1TNO partner in Solliance, Eindhoven, Netherlands
/2Universiteit Hasselt, Hasselt, Belgium
/3TNO, Petten, Netherlands

Perovskite – c-Si tandems are one route to reduce the cost price of renewable energy generation. The four terminal approach is promising because the top and bottom sections can be made separately. The top module in such a device could consist of the traditional monolithic interconnection design. However, a major disadvantage of this design is that it is very sensitive to partial shading as it is almost impossible to integrate protection against reverse bias. Connecting strings in parallel is an option to mitigate the magnitude of the reverse bias during partial shading events. In this study an LT Spice based electrical model was developed, the parameters used for both reverse and forward bias are based on cell measurements. This model was used to simulate various shading and interconnection scenarios. The simulations showed that the magnitude of reverse bias can be kept mild as long as the operating point of the partially shaded string is kept close to the maximum power point of the unshaded string. Further simulations proved that connecting strings in parallel will achieve this, as long as not all the strings are partially shaded. A top module with parallel connected strings in a tour terminal tandem can be realized because the c-Si bottom module allows some space to integrate current collecting structures (tabs) that can be used to connect strings of monolithically interconnected Perovskite cells in parallel. Supporting experiment data has shown that a module consisting of parallel connected strings of monolithically interconnected Perovskite cells can be shade tolerant.