Reliability of energy storage devices is one of the foremost preoccupations in Electric Vehicles development. Battery ageing, i.e. the time dependent degradation of battery energy and power, depends on the in-use solicitations endured by the storage system. The connection between solicitations and battery life must be analyzed and modeled to match battery in-service life with car lifetime. Large variation in pulse duration and amplitude make life prediction an intricate problem. Consequently, the first step of the methodology is the definition of a test protocol able to define a damage notion. In case of Li-ion batteries, impedance rise and capacity fade are clearly involved in damage evaluation. The protocol must estimate this impact and allow a sensitivity study in terms of damage. This paper presents different methods to estimate battery ageing and tries to give, for each, some of the advantages and disadvantages that could appear when modeling.
View Full Article