The impact of inhomogeneous particle size distribution on Li-ion cell performance under galvanostatic and transient loads

Abstract

Although small particle size and homogeneous particle size distribution are well-known for desired features, the electrode of Li-ion cells in reality consists of inhomogeneous particle sizes. Since large particle size can deteriorate the cell performance, it is essential to understand the electro- and physicochemical processes within the inhomogeneous electrode including large particles. In this paper, the effect of large particles within inhomogeneous electrode on the cell performance is investigated by using extended P2D model. On the basis of three particle sizes, inhomogeneous electrode is represented. The volume fraction distribution of these three particle sizes is varied creating four different electrode compositions. For a fair comparison, the sum of these volume fractions is fixed guaranteeing the same amount of active material within the electrode. A comparative study of four electrode compositions is carried out in order to investigate the impact of large particle portion on the power and energy performance under galvanostatic and transient loads. Simulation results show that higher portion of large particle size leads to unequal Li-ion distribution along the electrode leading to losses in useable power and energy.