ESTIMATION DEVICE, ESTIMATION METHOD, AND COMPUTER PROGRAM

An estimation device includes: a derivation unit (31) configured to derive a derivation history based on a current and a voltage of a lead-acid battery and a temperature of the lead-acid battery; a first specifying unit 31 configured to specify a specific gravity of an electrolyte solution; a second specifying unit (31) configured to specify at least one degree out 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 sulfation of a negative electrode; and a fourth degree of shrinkage of a negative electrode material based on the specified specific gravity, the derived derivation history, and at least one relationship selected from the group consisting of: a first relationship between the specific gravity and a first history, and the first degree; a second relationship between the specific gravity and a second history; and the second degree; a third relationship between the specific gravity and a third history; and the third degree; and a fourth relationship between a fourth history and the fourth degree; and an estimation unit (31) configured to estimate a degree of deterioration of the lead-acid battery based on the specified at least one degree.