Analysis of Peukert Generalized Equations Use for Estimation of Remaining Capacity of Automotive-Grade Lithium-Ion Batteries

Abstract

In this paper, it is shown that the Peukert generalized equations C = Cm/(1 + (i/i0)n), C = 0.522Cmtanh((i/i0)n/0.522)/(i/i0)n and C = Cmerfc((i/ik − 1)/(1/n))/erfc(−n) are applicable for capacity estimation of the automotive-grade lithium-ion batteries within the discharge current range, from 0 to 10 Cn. Additionally, it is shown here that all the parameters (Cm, n, i0 and ik) in the Peukert generalized equations under study have a clear physical meaning, unlike in the classical Peukert equation, in which all the parameters are just empirical constants. In addition, it is shown that, in the case of lithium-ion batteries, the dependence of their released capacity on the discharge current reflects the phase transition statistical pattern in the electrodes’ active substance, which follows the normal distribution law. As the Peukert equation is used in many analytical models, the better electrochemical and physical meaning and understanding of this equation and its clarification are of great practical importance.