A Practical Scheme to Involve Degradation Cost of Lithium-Ion Batteries in Vehicle-to-Grid Applications

Abstract

This paper concentrates on degradation of electric vehicle (EV) lithium-ion batteries in vehicle-to-grid (V2G) programs and proposes a practical wear cost model for EVs charge scheduling applications. As the first step, all the factors affecting the cycle life of lithium-ion batteries are identified and their impacts on degradation process are investigated. Subsequently, a general model for battery loss of cycle life is devised incorporating all the pertinent factors associated with charging and discharging activities in V2G applications. Modeling the battery wear cost as a series of equal-payments over the cycle life, a mechanism for calculating the cost incurred by EV users due to participation in V2G programs is developed. Taking into account the developed battery degradation cost model, EVs charge scheduling problem is revisited and it is formulated as a mixed integer linear programming problem. As the actual battery degradation cost and adopted charging strategy are mutually dependent, a novel iterative method is proposed to efficiently obtain the optimal solution to charge scheduling problem and calculate the associated wear price. Several case studies are presented to demonstrate the effectiveness and applicability of the proposed method in integrating the degradation cost of lithium-ion batteries into charge scheduling of V2G-capable EVs.