Besides leading the research and development of internal combustion engines, the Institute of VKA has also extended its expertise in the field of electromobility since more than 10 years ago. The activities include the development of battery management systems (BMS), simulation models and diagnostic algorithms as well as the battery cell characterization and battery lifetime examination.
Various measurements are required for the simulation and validation process for the investigation of novel battery technologies. The characterizations of electrical behavior, thermal behavior and aging behavior can be carried out at the VKA itself. A battery test chamber has also been developed in cooperation with the CMP, which is available for a wide range of thermal tests. Here, under controlled thermal conditions, it is possible to measure batteries in a voltage range from 0 to 800 V and a peak power of up to 300 kW.
Battery modelling researches are conducted at different levels in VKA, not only the empirical and electrical level but also in the very detailed electrochemical level. Within the NanoLiBa-Project, for example, which was supported by DFG, the methodology to analyse the very detailed and complicated electrode geometry was developed.
Thermal management is vital for the application of battery system in electromobility. Within one project supported by BMWi, a combination of an equivalent electric circuit battery model and a 3D finite-element thermal model was used in the analysis of thermal management under realistic EV operating conditions. Temperature and electric potential measurements, performed at the cell and module levels, were used for model calibration.
Battery management system
For a safe and efficient use of battery system in electrified vehicles, a battery management system is necessary. Within the framework of the ‘‘Europahybrid’’ project, VKA has, in cooperation with FEV Europe GmbH, developed a predictive battery management algorithm in EV and HEV applications. This algorithm allows the prediction of battery’s electrical and thermal status based on the cell resistance and voltage gradient map.