BATTERY MANAGEMENT DEVICE

A battery management device includes: an acquisition unit that acquires a degradation evaluation value for evaluating a degree of advance of a high-rate degradation state of a lithium-ion secondary battery; a high-frequency signal supply unit that supplies a high-frequency signal at a frequency of 0.1 MHz or higher to the lithium-ion secondary battery; a detection unit that detects a value of a real part of alternating current impedance from the lithium-ion secondary battery supplied with the high-frequency signal; a calculation unit that calculates an amount of Li deposition in the lithium-ion secondary battery from the detected value of the real part of the alternating current impedance; and a control unit that, as the calculated amount of Li deposition increases, reduces an upper-limit degradation evaluation value for the lithium-ion secondary battery that is a criterion for determining whether the lithium-ion secondary battery is expected to reach the high-rate degradation state.