Effect Of Gradient Porosity On The Transmission Characteristics Of Lithium-ion Batteries

With the increasing demand for lithium-ion batteries, high energy density and high power density lithium-ion battery technology has become one of the research hotspots. The diffusion process of lithium ions in the anode region is one of the main factors limiting the performance of lithium-ion batteries, and by optimising the electrode pore structure, the diffusion resistance of lithium ions in the electrolyte has been reduced to improve the discharge capacity of lithium-ion batteries. A threedimensional electrochemical-thermal coupling model was utilised to elucidate the electrochemical processes occurring within lithium-ion batteries. The impact of gradient porosity on the distribution of local SOC, liquid-phase lithium ion concentration, and overpotential of lithium-ion batteries was investigated by comparing the simulation results of gradient porosity with those of homogeneous porosity at discharge multiplicities of $1 \mathrm{C}, 0.5 \mathrm{C}$, and 0.2 C. The findings revealed that gradient porosity enhances the utilisation rate per unit of active material and accelerates the diffusion rate of liquid phase ions. These outcomes are of paramount importance for the engineering of electrodes for high energy and high power applications.