Lithium ion battery performance for different size of electrode particles and porosity

Abstract

Nowadays, the interest of high proficiency of Lithium ion batteries is increasing as they provide high volumetric energy densities and to meet the demand of exponentially growth of electronic devices. Furthermore, LIB has shown their potential to offer high performance rechargeable battery in the research of electric vehicles. Electrochemical process of Lithium ion batteries encompasses a complex ion transport between the anode and cathode within an electrolyte. The multiscale LIB model consists of charge transport within electrode particle and in electrolyte and the reaction rate at the electrolyte-electrode particle interface which directly relating the geometry of microstructure (the size of particles, about 1nm) to the behaviour in macroscopic model (within the thickness of electrode, about 1 µm). Thus, the geometry of cell and the interfacial behaviour are significantly control the rate of reaction rate. This study concerns about the effect of geometry variations of cell upon the discharge curve of LiFePO4 cathode material. The electrochemical model is solved using Method of Lines technique by discretising the spatial variable using Finite Difference Method. The simulation result is verified with experimental data of LiFePO4 cell by Yu et. al. [14]. The effect of different sizes of particles and volume fractions upon the cell performance are examined. It has been shown that decreasing the size of electrode particles produce high cell potential but slightly low capacity. On the other hand, the optimal volume fraction is shown to be εv = 0. 0000 provided that all the particles are spherical and of the same size. Smaller volume fractions resulted in low capacity.