The SiCWell project, funded by VDI/VDE Innovation + Technik GmbH under grant 16EMO0263, aimed to investigate how fast‑switching silicon carbide (SiC) power converters affect the lifetime of traction batteries. The overall objective was to develop life‑time models that enable optimal system design. Solfas Technologie GmbH was responsible for creating a battery test system capable of cycling cells while superimposing direct‑current (DC) and high‑frequency alternating‑current (AC) ripple currents, thereby reproducing the electrical stresses experienced in real vehicle applications.
To meet this requirement, Solfas conducted extensive preparatory work, including test bench construction, numerical simulations, and analytical calculations. These activities defined the necessary hardware components: precision voltage and current measurement units, a control architecture, a cooling scheme, sizing of the power section, and the software logic for automated operation. The design was validated through iterative prototyping. The first prototype was assembled according to detailed schematics, printed circuit board layouts, and documentation. Functional tests confirmed that the system could deliver the prescribed DC and AC waveforms simultaneously, and the results guided refinements in both hardware and firmware. Once the prototype met all specifications, Solfas ordered additional units for production. The final devices were mounted in a standard 19‑inch rack and fully wired, creating a scalable test platform that can be deployed in multiple laboratories.
Parallel to hardware development, Solfas engineered the control software that interfaces with a PC. The software manages waveform generation, data acquisition, and real‑time monitoring, providing a user‑friendly environment for executing complex test sequences. Throughout the project, Solfas worked closely with the Technical University of Berlin (TU Berlin), specifically the Electrical Energy Storage Technology (EET) and Mechanical and Technical Department (MDT) groups. TU Berlin supplied laboratory infrastructure, performed data collection, and carried out detailed analysis of the recorded measurements. This collaboration ensured that the test system’s performance aligned with the scientific goals of the SiCWell project.
The project timeline spanned from 1 September 2018 to 30 November 2022, with the final report submitted on 29 September 2023. The COVID‑19 pandemic in 2020 limited laboratory access, causing a temporary halt in test operations. Nevertheless, the first cycling experiments resumed in the third quarter of 2020, and additional modules were integrated into the test rigs thereafter. In 2021, further firmware and control‑software optimisations were implemented in cooperation with TU Berlin’s EET and MDT teams. Continuous data evaluation led to incremental improvements in the system’s functionality and reliability.
By the end of the project, Solfas had successfully delivered a fully operational battery test system that meets the stringent requirements for studying SiC inverter effects on traction battery degradation. The system’s modular design, combined with robust software control, provides a versatile platform for future research and development. The collaboration between Solfas, TU Berlin, and Daimler AG—who supplied battery cells and test parameters—ensured that the test conditions accurately reflected real‑world vehicle scenarios, thereby enhancing the relevance of the resulting life‑time models for industry application.