| 摘要 |
PROBLEM TO BE SOLVED: To shorten a working process and shorten a measuring time on diagnosis, and to detect capacity deterioration of a secondary battery without delay, by executing capacity deterioration diagnosis by using a portable instrument. SOLUTION: An internal resistance measuring circuit 3d sends an alternating current or a direct current through an upper part node of a protection circuit 1b and a negative electrode side node of the secondary battery 1a, and simultaneously measures the change of a voltage developed across the secondary battery 1a between a node between the protection circuit 1b and the secondary battery 1a and the negative electrode side node of the secondary battery 1a, and divides the measured value of the change of the voltage developed across the secondary battery 1a by the value of the alternating current or the direct current, to thereby determine the internal resistance R of the secondary battery 1a. The internal resistance is increased following capacity deterioration in the secondary battery. Therefore, the internal resistance determination circuit 3e determines as the capacity deterioration of the secondary battery, when the internal resistance of the secondary battery 1a exceeds a prescribed internal resistance value, and displays it on a display part 2. |
