| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for estimating an open circuit voltage of a battery capable of estimating comparatively accurately without waiting until a state that can be regarded as an equilibrium state is obtained. SOLUTION: A no-load estimation means 5-1 estimates a no-load state by detecting that a current flowing in the battery 1 becomes below a fixed value determined beforehand based on a current measured by a current measuring means 2. By using the estimation point of time as a start point, an open circuit voltage estimation means 5-2 allows a voltage measuring means 3 to measure respectively terminal voltages v1, v2, v3 of the battery at the three points of time after elapsed times t1, t2, t3 from the start point. Assuming that an elapsed time is t, the terminal voltage is V and a is a coefficient, the times t1, t2, t3 and the voltages v1, v2, v3 are substituted for solutions of b in three simultaneous equations set up on an estimation calculation formula V=[a/(t-c)]+b determined beforehand by using the axis of a time c corresponding to a time difference between the start point and a point of time when the current becomes below the fixed value and the axis of the voltage b as asymptotic lines, to thereby estimate the open circuit voltage of the battery. COPYRIGHT: (C)2004,JPO
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