Fraunhofer Energy AllianceRoad vehicles are operated in the partial load range during the predominant time of their service life. For short-term "high-performance" activities considerable additional resources must be reserved. For pure combustion vehicles, this results in a target conflict between performance and range which leads to significant efficiency losses. The energy storage of battery-operated vehicles is designed for maximum range. Regular phases of high load accelerate the aging of this type of battery. The special high-performance battery developed as part of the FSEM II project ( "Li Booster") is used whenever short-term power peaks (<1min) occur. Your charging characteristic also supports the efficient feedback of braking energy into the drive system.
In order to ensure the required functionality, the use of accumulators with a particularly high power density is necessary. At the same time, however, high intrinsic safety, cyclical stability and low aging are to be ensured, all in the wide temperature range typical for the operation of road vehicles. At the Fraunhofer ISIT a lithium accumulator could be developed which can be charged and discharged with up to 50 C. For this purpose, a material combination with lithium titanate (Li4Ti5O12) as anode material and lithium manganese oxide (LiMn2O4) was chosen as the cathode material, which can ensure the required high intrinsic safety and low aging.
In addition to these high-performance cells, the Fraunhofer ISIT has developed a scalable battery management system (BMS) that offers a wide range of applications. The electronics are designed modularly and thus allows an adaptation of the operating voltage to the conditions of the respective application. In the case of the Li booster, these are 240 to 370 volts at a current of 100 amps, corresponding to a power of 30 kilowatts.