Apparatus and method for estimating charge rate of secondary cell

摘要

In charge rate estimating apparatus and method for a secondary cell, a current flowing through the secondary cell is measured, a voltage across terminals of the secondary cell is measured, an adaptive digital filtering is carried out using a cell model in a continuous time series shown in an equation (1), all of parameters at one time are estimated, the parameters corresponding to an open-circuit voltage which is an offset term of the equation (1) and coefficients of A(s), B(s), and C(s) which are transient terms, and, the charge rate is estimated from a relationship between a previously derived open-circuit voltage V₀ and the charge rate SOC using the open-circuit voltage V₀, $\begin{array}{cc}V=\frac{B\left(s\right)}{A\left(s\right)}.I+\frac{1}{C\left(s\right)}.V_0,& \left(1\right)\end{array}$ wherein s denotes a Laplace transform operator, A(s), B(s), and C(s) denote poly-nominal functions of s.