Experimental Study on Influence of Temperature and C-Rate of Discharge on Performance of In-House-Fabricated 30-Ah Li-Ion Prismatic Cell Made With Lithium Iron Phosphate and MCMB

Abstract

An experimental study was carried out to quantify the influence of temperature and different C-rate of discharge on in-house fabricated lithium-ion (Li-ion) cell. A 30-Ah Li-ion cell is made of lithium iron phosphate (LFP) cathode and meso carbon microbeads (MCMB) anode in prismatic configuration. The capability of Li-ion cell is defined by discharge capacity, voltage, and power at different C-rate of discharge. Influence of 4 different current rates (C/5, C/2, 1C, and 2C) at 5 different temperatures (–20, 0, 20, 40, and 60 °C) were studied. High discharge rate increases the current density of cell which affect mass transport at electrode surface and electrolyte. Increased ohmic and concentration polarization at a high rate of discharge decrease the original capacity. The average discharge voltage of the cell is reduced gradually as operating temperature drops to below 20 °C. Electrochemical impedance (EI) were measured on Li-ion cell in the different frequency domain at different temperatures (–20, 0, 20, and 60 °C). The obtained impedance spectra were examined with an equivalent circuit using the Zman software. The ohmic and charge-transfer resistance displayed a solid dependence with respect to temperature.