How electrode thicknesses influence performance of cylindrical lithium-ion batteries

A design of anode and cathode thicknesses of lithium-ion batteries is a dilemma owing to the facts: 1) increasing the electrodes thicknesses is able to improve the energy density, but the thermal characteristics become worse and vice versa; and 2) the method of quantitative evaluation of the design lacks basically. In this work, an electrochemical-thermal coupled model is developed to systematically study the battery performance including electrical and thermal behaviors. Based on the on-line energy efficiency and thermal energy conversion efficiency, a method is proposed to evaluate the adjustments of anode and cathode thicknesses through comparison of the battery's electrical and thermal performance. Results show that the electrode thickness has significant influences on discharge performance, heat generation and temperature distribution. The effects of the electrode thickness on the energy efficiency and the thermal energy conversion efficiency are quantitatively discussed, respectively. The thermal energy conversion efficiency and the max temperature rise as target boundary conditions are proposed to optimize the design of lithium-ion batteries.