There are numerous models of rechargeable batteries in the current literature. Some of them are complicated electrochemical approaches; others, are given by simple analogies. However, simple models with electrochemical states capable of describing important quantities, like the rate capacity effect and the recovery effect, are hard to find. In this paper, based on an electrochemical approach, we present a generalized model suitable for use in BMS applications, which takes into account explicitly the rate capacity effect and the state of charge. Moreover, the model is thought up for general energy storage processes based on mass transport and charge transfer. The proposed general model approach is able to interpret the most commonly used models in the literature.