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Institute of Energy and Climate Research
IEK-5 Photovoltaics

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Integrating storage technologies

Integrating storage technologies in the future renewable energy system is one of the most important nowadays problems. Recent developments in small scale consumer electronics, trend for implementing “Internet of Things” and smart house smart cities concepts make it imperative to have cheap, wireless and all-inclusive integrated power solution for all-time operation electronics.

Our group is working on development of single and multi-junction thin-film silicon solar cells and modules which are used to charge lithium ion batteries for energy storage. Aiming at ultimate compactness, simplicity and scalability we consider monolithic integration of a storage cell (battery) with thin-film PV cell/module in 2 different configurations. The 2-terminal configuration – a direct cell-to-cell integration is studied where the PV charges the battery without the use of charge controller. The 3-terminal configuration - the PV cell/module and battery are integrated with a common contact layer in between to make it possible to use DC-DC converters and charge controllers for power conditioning. One other aspect of our work is the investigation of thin-film silicon solar cells’ characteristics under different light intensities and spectra. This is very important aspect because it gives us insight into the potentials and limitations of the PV-battery indoor and outdoor operations under artificial lights.


S. N. Agbo, T. Merdzhanova, S. Yu, H. Tempel, H. Kungl, R. A. Eichel, U. Rau, O. Astakhov, “Development towards cell-to cell monolithic integration of a thin-film solar cell and lithium-ion accumulator”, Journal of Power Sources 327, (2016) 340.

S. N. Agbo, T. Merdzhanova, U. Rau, O. Astakhov, “Illumination intensity and spectrum-dependent performance of thin-film silicon single and multijunction solar cells”, Solar Energy Materials and Solar Cells 159 (2017) 427.

F. Sandbaumhüter, S. N. Agbo, C.-L. Tsai, O. Astakhov, S. Uhlenbruck, U. Rau, T. Merdzhanova, Compatibility study towards monolithic self-charging power unit based on all-solid thin-film solar module and battery, Journal of Power Sources 365, (2017) 303.