Rapid Assessment of EV Battery Without Driving the Car

The high-voltage (HV) battery of an electric vehicle (EV) is the most expensive component in a vehicle. These should generally be designed for the lifespan of the vehicle, but mobile use in road vehicles is a particular challenge. In addition to the environmental conditions, the remaining usable capacity depends very much on user behavior. The batteries are therefore subject to a certain amount of wear and tear. For users, this is associated with restrictions in range and for owners – be it the original owner or the used car buyer – this represents a financial risk. Once the vehicle reaches a certain age, repairing or replacing the battery is no longer economical. The condition of the battery in terms of the actual remaining capacity has a significant influence on the used car market. This information is very important for both sellers and buyers. In recent years, various battery test procedures have been introduced in order to be able to use them for assessing the vehicle HV battery. DEKRA has developed and launched an assessment system with a special feature: a quick assessment. It is therefore tailored to the specific use case of used vehicle valuation. The challenge of an independent evaluation is sufficient powerful electric stimulation of the battery, which is implemented by a test drive in the form of an acceleration. However, for technical, organizational, or infrastructural reasons an acceleration drive is not in every situation possible. Accordingly, alternative methods are being investigated – instead of stimulation by discharging by means of a short test drive, stimulation by charging was also investigated. Two basic charging approaches – DC and AC charging – integrated into a new M2M architecture and the results are presented according to their accuracy.