ultraBatt – Intelligent Design and Operation Strategies for Ultra-Fast Charging of Battery Systems of Electric Vehicles
Motivation:
In addition to the transformation of the individual mobility to low-emission battery electric vehicles, a change in the commercial vehicle and the transport sector toward electric mobility is also necessary in order to be able to significantly reduce greenhouse gas emissions. High requirements on payloads and high-frequency usage, which are required for the economical operation of the vehicles, pose challenges for the energy storage system. Using large energy storage systems to enable long ranges, fast charging can help to increase the acceptance of electrified commercial vehicles. With the currently used battery cell technology, a large energy storage system is directly linked to a high mass and large resource consumption, so that the fast charging of batteries seems to be a promising solution.
Charging at high currents leads to various problems at both the battery cell and battery module levels, resulting in uneven aging of the battery cells in the module and consequent loss of capacity.
Objectives and procedure:
The research project aims to reduce the charging time of a battery module to less than 15 minutes and at the same time to increase the remaining useful lifetime compared to a reference module. This goal shall be achieved by various approaches. On the one hand, new charging strategies will be developed since the charging strategies currently used are neither particularly fast nor particularly gentle on the battery storage system. Moreover, cell-specific data (e.g., the cell capacity or the impedance) will be used and the negative effects of high charging currents will be reduced by an adapted arrangement of the battery cells in the module. In addition, the current flow in the module can be influenced by the contacting of the cell trough laser beam welding and thus, the charging current of individual cells and the resulting heat generation can be controlled. Due to the high flexibility of laser beam welding, the welded joint can be individualized for each battery cell in the module, and thus, cell-specific scattering can be compensated. In order to determine a well-suited weld length and shape, Artificial Intelligence will be used for processing the cell data and the module data to determine the weld geometry.