DEVICE FOR MEASURING DEGRADATION, RECHARGEABLE BATTERY PACK, METHOD FOR MEASURING DEGRADATION, AND PROGRAM

摘要

Battery detection units measure the voltages between both terminals of rechargeable batteries. A current detection unit measures the current flowing through the rechargeable batteries. A control unit retains, in advance, the value of an external impedance that exists in a discharge path outside of the rechargeable batteries; discharges the rechargeable batteries from a first measurement time to a second measurement time at which point a discharge capacity, aggregated on the basis of the discharge current measured by the current detection unit, reaches a predetermined discharge capacity reference value; calculates an internal impedance, which is present inside of the rechargeable batteries, on the basis of the voltages measured by the battery detection units, at the second measurement time; calculates a second discharge voltage at the second measurement time by multiplying the discharge current measured by the current detection unit by the sum of the external impedance and the internal impedance; and calculates the recovery capacity of the rechargeable batteries on the basis of the first discharge voltage at the first measurement time, and the second discharge voltage and the discharge capacity reference value.