Patent ID: 8234087

Claim:
A battery status detecting method performed by a battery status detecting apparatus that is connected to a secondary battery to detect a battery status of the secondary battery that supplies power to an electrical load, the method comprising: a current measuring step of measuring a discharge current value of the secondary battery; and an estimating step of the battery status detecting apparatus estimating a dischargeable capacity or a dischargeable time of the secondary battery that is defined as a capacity or time dischargeable with the measured discharge current value before a voltage of the secondary battery drops to a predetermined voltage specified by the electrical load, the estimating being performed based on discharge characteristics of the secondary battery, the discharge characteristics indicating relationships between a discharge capacity and a discharge rate that are observed when the voltage of the secondary battery drops to the predetermined voltage specified by the electrical load, wherein the discharge characteristics indicate a relationship between a discharge capacity and the discharge current value of the secondary battery, and wherein the discharge characteristics are represented by an expression described as: Q=A·I+B ·ln ( I )+ C −( FCC −remaining capacity) or Q=A′·I+B ′·(1/ I )+ C ′−( FCC −remaining capacity) where Q represents the dischargeable capacity of the secondary battery, I represents the discharge current value of the secondary battery, FCC represents a full charge capacity of the secondary battery, A, B, and C represent coefficients of the expression, and A′, B′, and C′ represent coefficients of the expression.