A battery state estimation method includes: periodically measuring voltage and current of a battery in use to generate a voltage value and a current value; using an adaptive filter to generate a G parameter value for a G parameter and an H parameter value for an H parameter in real time from the voltage value and the current value, the G and H parameters indicating a present state of the battery; and using the G parameter value and the H parameter value to estimate the present state of the battery in real time. The G parameter is a parameter that represents sensitivity of the voltage to changes in the current of the battery, and the H parameter is a parameter that represents an effective potential determined by local equilibrium potential distribution and resistance distribution inside the battery.