An apparatus for estimating resistance characteristics of a battery based on a battery voltage variation pattern, comprising:
- an open circuit voltage calculator for calculating a battery open circuit voltage from a battery voltage variation pattern measured at the present and in the past;
- a weighted mean resistance calculator for calculating a battery resistance parameter from a battery current and a difference between the battery open circuit voltage and a battery voltage, and calculating a weighted mean resistance from battery resistance parameters calculated at the present and in the past;
- a weighted mean resistance convergence calculator for calculating a weighed mean resistance convergence value by repeatedly calculating a weighted mean sequence;
- and
- a resistance characteristic estimator for estimating a battery resistance from the weighted mean resistance convergence value.