Method for determining deterioration of accumulator battery, method for measuring internal impedance of secondary battery, equipment for measuring internal impedance of secondary battery, equipment for determining deterioration of secondary battery, and power supply system
First Claim
Patent Images
1. A method for determining deterioration of secondary battery based upon internal resistances of the secondary battery, which comprises the steps of:
- calculating the internal impedances from currents and voltages of the secondary battery measured in the condition that predetermined currents are applied to the secondary battery;
determining coefficients of respective terms of an approximate function which comprises a cubic or more polynomial expression and approximates the temperature characteristics of the secondary battery, based upon the calculated internal impedances and the measured temperature of the secondary battery;
calculating a specified internal impedance, which is a presumed internal impedance value at a predetermined specified temperature, with use of the cubic or more polynomial expression based upon the determined coefficients;
determining deterioration of the secondary battery based upon the specified internal impedance; and
displaying the determined deterioration of the secondary battery.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for determining deterioration of accumulator battery hooked up with loads in a system based on results of measuring internal resistances of an accumulator battery, the method comprising the steps of;
- predetermining as a specified temperature a temperature at which the deterioration of the accumulator battery is determined;
- calculating in advance temperature correction coefficients of the internal resistances from changes of the internal resistances depending on temperatures;
- predetermining resistance-voltage conversion factors to convert between the internal resistances at the specified temperature and terminal discharge voltages of the accumulator battery which are obtained at the specified temperature under a condition of flowing predetermined discharge currents from the accumulator battery;
- measuring the internal resistances of the accumulator battery and temperature of the accumulator battery at an internal resistance measurement;
- converting the measured internal resistance values into the internal resistance values at the specified temperature with use of the temperature correction coefficients of the internal resistances;
- converting the internal resistance values at the specified temperature into the terminal discharge voltage values of the accumulator battery at the specified temperature with use of the resistance-voltage conversion factors; and
- determining whether the accumulator battery is deteriorated or not by means of comparison of the terminal discharge voltage values of the accumulator battery at the specified temperature and a predetermined threshold value as a deterioration judgment standard.
-
Citations
11 Claims
-
1. A method for determining deterioration of secondary battery based upon internal resistances of the secondary battery, which comprises the steps of:
-
calculating the internal impedances from currents and voltages of the secondary battery measured in the condition that predetermined currents are applied to the secondary battery; determining coefficients of respective terms of an approximate function which comprises a cubic or more polynomial expression and approximates the temperature characteristics of the secondary battery, based upon the calculated internal impedances and the measured temperature of the secondary battery; calculating a specified internal impedance, which is a presumed internal impedance value at a predetermined specified temperature, with use of the cubic or more polynomial expression based upon the determined coefficients; determining deterioration of the secondary battery based upon the specified internal impedance; and displaying the determined deterioration of the secondary battery. - View Dependent Claims (2, 3, 4, 5)
-
-
6. An equipment for determining deterioration of secondary battery based upon the internal resistances of the secondary battery supplying electric power with loads includes:
-
circuits which can apply current pulses to the secondary battery; detection means which measures currents and voltages of the secondary battery; temperature sensors which measure the temperature of the secondary battery; and control means which calculates the internal impedances from the measurement results of the detection means in condition that the circuits apply current pulses to the secondary battery, determines coefficients of the respective terms of an approximate function which comprises a cubic or more polynomial expression and approximates the temperature characteristics of the secondary battery, calculates a specified internal impedance, which is a presumed internal impedance value at a predetermined specified temperature, with use of the cubic or more polynomial expression based upon the determined coefficients, and determines deterioration of the secondary battery based upon the calculated specified internal impedance. - View Dependent Claims (7, 8, 9, 10, 11)
-
Specification