Patent ID: 7482784
Filing Date: 2009-01-27
Classification: G01R,H02J

Abstract:
1. A degradation judgment circuit for a secondary battery used in a main apparatus comprising: a time measurement portion; a state data acquisition portion; an estimation portion; and a judgment portion, wherein the time measurement portion measures a connect time during which the secondary battery is connected to the main apparatus before judging degradation of the secondary battery, wherein the state data acquisition portion acquires state data including data that shows an avenge temperature and a number of charge/discharge cycles of the secondary battery during a period from when the secondary battery is connected to the main apparatus to when degradation of the secondary battery is judged, the estimation portion estimates an internal resistance value or a change in internal resistance value that corresponds to a combination of the connect time measured by the time measurement portion, the average temperature, and the number of charge/discharge cycles included in the state data by using data or a function that associates a combination of various values of the connect time, the average temperature, and the number of charge/discharge cycles with the internal resistance value or the change in internal resistance value, and the judgment portion judges degradation of the secondary battery based on the result of the estimation by the estimation portion.