Study on the effects of electrode volume fraction and electrode particle radius on dynamic electrochemical-thermal-aging coupling characteristics of lithium cell based on cylindrical cell design method

Abstract

Electrode volume fraction and electrode particle radius are important electrode parameters for the lithium cell design and deeply influence the electrochemical-physical processes inside lithium cell, which is still insufficiently clear. In order to obtain the effects of electrode parameters on lithium cell, a combine method of the dynamic electrochemical-thermal-aging coupling model and cylindrical cell design was proposed. Simulation was conducted at charge rate 1C. Cell temperature, current density and Solid-Electrolyte-Interface at ambient temperature 25 °C, and total strain energy density and lithium plating at ambient temperature −5 °C were analyzed. As electrode volume fraction or electrode particle radius increases, maximum temperature and maximum temperature difference of lithium cell increase. When electrode volume fraction increases from 0.3 to 0.7, maximum temperature of cell increases by 2.6 °C at least. Current density peak increases with the increase of the positive electrode volume fraction or electrode particle radius. When electrode volume fraction increases from 0.3 to 0.7, current density peak increases by 44 %∼74 %. As electrode volume fraction increases, total strain energy density Ws decreases in the early stage of charge, while increases in the late stage of charge. As the negative (or positive) electrode particle radius increases, Ws of the negative (or positive) electrode increase, while Ws of the positive (or negative) electrode decreases. Solid-Electrolyte-Interface thickness increases with the increase of the electrode volume fraction or electrode particle radius. The effect range of negative electrode volume on lithium plating is 0.5 ∼ 0.7. The lithium metal thickness increase with the increase of the positive electrode volume fraction. As the negative or positive electrode particle radius increases, the lithium metal thickness increase or decrease, respectively.