$\eta_{max}$-Charging Strategy for Lithium-Ion Batteries in V2G Applications

Abstract

The design of charging strategies for lithium-ion (Li-ion) batteries depends on the application. In electric vehicle applications, high charging speed and long battery life are essential requirements. However, with the advent of vehicle-togrid (V2G) and potential remuneration for electric grid support, maximum user profit could gain increasing interest through efficient operation that also optimizes battery health. Conventional constant-current constant voltage (CCCV) and constant-power constant-voltage (CPCV) charging strategies do not include the optimum efficiency of the battery and charging stations. In this paper, a charging strategy is introduced aiming at maximizing the instantaneous efficiency (ηmax) of the Li-ion battery and the charging station which minimizes the energy waste. For this purpose, 18650 Li-ion cells and a dual-active-bridge (DAB) converter are considered in the simulations and experimental validations. The results show that the ηmax-charging strategy outperforms conventional CCCV and CPCV charging strategies in terms of efficiency and material-lifetime compatibility.

Single-Wire Model for Silicon Microwire Electrode of Lithium-ion Batteries

“…The detailed analytical calculations for the solid phase diffusion are derived by the authors in [29] and are presented in the Appendix A. The Finite Element Method (FEM) based solution is derived and presented in Appendix B.…”

Integrated Strategy for Optimized Charging and Balancing of Lithium-ion Battery Packs

“…In these methods, voltage/current limits can be ensured, but thermal regulation and balancing are assessed sep-arately or not assessed at all. More complex and more effective charging strategies in closed-loop operation use the battery states as feedback and provide current, voltage, power, charge and thermal regulation [4], [9], [10]. To implement these strategies, modelling the battery dynamics and optimization algorithms are essential.…”