Performance of LiFePO4/C and carbon fibers composite as cathodes in lithium-ion batteries and battery modeling

Abstract

Currently, the cathode material LiFePO4/C is the most promising active material for high-power lithium-ion batteries for electric vehicle applications and it has been observed that its response is also dependent on the nature of the carbon used as support. This paper presents the preliminary results from the synthesis of LiFePO4 supported on carbon fibers where phosphate and fibers are synthesized together at a single stage. The electrodes built with this material have a good electrochemical response with the typical behavior of LiFePO4. In addition, the behavior of these materials has been characterized from the viewpoint of the electrochemistry of charge/discharge processes in order to provide knowledge for the global modeling of batteries. A Battery Management System (BMS) is also currently being developed in order to control the operating conditions and the state of charge of Li-ion batteries. The development of a BMS requires an adequate modeling of the dynamic accumulation processes taking place in the battery. A general model has been derived and validated in terms of the experimental performance of a Li-ion battery, some results are presented below.