Patent ID: 7323848
Filing Date: 2008-01-29
Classification: G01R

Abstract:
1. A battery charging state arithmetic operation device, characterized by comprising: battery voltage detection means for detecting a voltage of a battery; battery current detection means for detecting a current of the battery; first current-voltage characteristic storage means for approximately obtaining a current-voltage characteristic of the battery in a first state as a currently used state by using voltage values and current values detected by the battery voltage detection means and the battery current detection means at plural sampling points and for storing it as a first current-voltage characteristic; second current-voltage characteristic storage means for previously storing a second current-voltage characteristic in a second state where amount of extractive energy is smaller than that in the first state; specified current value storage means for storing a specified load current value of the battery; battery voltage calculation means with specified load for calculating a first battery voltage when the battery current is at the specified load current value by using the first current-voltage characteristic stored in the first current-voltage characteristic storage means and for calculating a second battery voltage when the battery current is at the specified load current value by using the second current-voltage characteristic: and charging state arithmetic operation means for calculating a charging state of the battery in the first state by using the first and the second battery voltages calculated by the battery voltage calculation means with specified load.