ESTIMATION DEVICE, ESTIMATION METHOD, AND COMPUTER PROGRAM

An estimation device includes: a deriving unit () that derives a derivation history based on a current and a voltage of a lead-acid battery and a temperature of the lead-acid battery; a specifying unit that specifies at least two degrees of a first degree of softening of a positive electrode material, a second degree of corrosion of a positive electrode grid, a third degree of negative electrode sulfation, and a fourth degree of shrinkage of a negative electrode material based on the derived derivation history and at least two relationships selected from the group consisting of: a first relationship between a first history based on the current, the voltage, and the temperature of the lead-acid battery, and the first degree; a second relationship between a second history and the second degree; a third relationship between a third history and the third degree; and a fourth relationship between a fourth history and the fourth degree; and an estimating unit () that estimates a degree of deterioration of the lead-acid battery based on the specified at least two degrees.