Method and device for judging the condition of secondary batteries and method for regenerating secondary batteries
First Claim
1. A method for judging the condition of a secondary battery by applying an AC voltage to the secondary battery to detect a quantity of electricity, which is related to an impedance of the secondary battery, or a quantity of electricity, which is related to the maximum power density, and judging the performance of the secondary battery based on the detected quantity of electricity, characterized in that a quantity of electricity related to the component of the impedance of the secondary battery, which does not vary with the frequency component of the AC voltage, is obtained as a DC impedance related quantity of electricity, and the quantity of electricity related to the component of the impedance of the secondary battery, which varies with the frequency component of the AC voltage, is obtained as an AC impedance related quantity of electricity, and the secondary battery is judged good when both said DC impedance related quantity of electricity and said AC impedance related quantity of electricity are respectively predetermined values or less while the secondary battery is judged inferior when both said DC impedance related quantity of electricity and said AC impedance related quantity of electricity are respectively more than predetermined values.
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Abstract
The internal resistance related value which is related to the internal resistance of a secondary battery is compared with a previously obtained relation between the internal resistance related value and battery condition to judge the battery condition of the secondary battery. Since the internal resistance related value is a value related to the internal resistance which closely depends on the battery condition, the battery condition can be judged in detail based on the above relation. And the internal resistance related value can be obtained more speedily with a predetermined method. On the other hand, when the level of the degradation of a negative electrode is low, an electrolyte is supplemented, and when the level of the degradation of the negative electrode is high, a reducing agent is added to the electrolyte to regenerate the secondary battery. With this regenerating method, the performance of the negative electrode can be recovered without degrading a positive electrode.
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3 Claims
- 1. A method for judging the condition of a secondary battery by applying an AC voltage to the secondary battery to detect a quantity of electricity, which is related to an impedance of the secondary battery, or a quantity of electricity, which is related to the maximum power density, and judging the performance of the secondary battery based on the detected quantity of electricity, characterized in that a quantity of electricity related to the component of the impedance of the secondary battery, which does not vary with the frequency component of the AC voltage, is obtained as a DC impedance related quantity of electricity, and the quantity of electricity related to the component of the impedance of the secondary battery, which varies with the frequency component of the AC voltage, is obtained as an AC impedance related quantity of electricity, and the secondary battery is judged good when both said DC impedance related quantity of electricity and said AC impedance related quantity of electricity are respectively predetermined values or less while the secondary battery is judged inferior when both said DC impedance related quantity of electricity and said AC impedance related quantity of electricity are respectively more than predetermined values.
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