DEGRADATION MEASUREMENT DEVICE, SECONDARY BATTERY PACK, DEGRADATION MEASUREMENT METHOD, AND PROGRAM
First Claim
1. A degradation measurement device comprising:
- a battery sensing section that measures a voltage across a secondary battery;
a current sensing section that measures a current flowing through said secondary battery; and
a control section that holds in advance the value of an external impedance present in a discharge path outside said secondary battery, discharges said secondary battery from a first measurement time to a second measurement time at which an integrated discharge capacity based on a discharge current measured by said current sensing section becomes equal to a predetermined discharge capacity reference value, calculates an internal impedance present in said secondary battery at said second measurement time based on the voltage measured by said battery sensing section, calculates a second open voltage at said second measurement time by multiplying the sum of said external impedance and said internal impedance by the discharge current measured by said current sensing section, and calculates a recovered capacity of said secondary battery based on a first open voltage at said first measurement time, said second open voltage and said discharge capacity reference value.
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Accused Products
Abstract
A battery sensing section measures a voltage across a secondary battery. A current sensing section measures a current flowing through the secondary battery. A control section holds the value of an external impedance present in a discharge path outside the secondary battery, discharges the secondary battery from a first time to a second time at which an integrated discharge capacity based on a measured discharge current becomes equal to a predetermined discharge capacity reference value, calculates the internal impedance present in the secondary battery at the second time based on the measured voltage, calculates the second open voltage at the second time by multiplying the sum of the external impedance and the internal impedance by the measured discharge current, and calculates the recovered capacity of the secondary battery based on the first open voltage at the first time, the second open voltage and the discharge capacity reference value.
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Citations
14 Claims
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1. A degradation measurement device comprising:
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a battery sensing section that measures a voltage across a secondary battery; a current sensing section that measures a current flowing through said secondary battery; and a control section that holds in advance the value of an external impedance present in a discharge path outside said secondary battery, discharges said secondary battery from a first measurement time to a second measurement time at which an integrated discharge capacity based on a discharge current measured by said current sensing section becomes equal to a predetermined discharge capacity reference value, calculates an internal impedance present in said secondary battery at said second measurement time based on the voltage measured by said battery sensing section, calculates a second open voltage at said second measurement time by multiplying the sum of said external impedance and said internal impedance by the discharge current measured by said current sensing section, and calculates a recovered capacity of said secondary battery based on a first open voltage at said first measurement time, said second open voltage and said discharge capacity reference value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A secondary battery pack comprising:
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a secondary battery capable of being charged and discharged; a battery sensing section that measures a voltage across said secondary battery; a current sensing section that measures a current flowing through said secondary battery; and a control section that holds in advance the value of an external impedance present in a discharge path outside said secondary battery, discharges said secondary battery from a first measurement time to a second measurement time at which an integrated discharge capacity based on a discharge current measured by said current sensing section becomes equal to a predetermined discharge capacity reference value, calculates an internal impedance present in said secondary battery at said second measurement time based on the voltage measured by said battery sensing section, calculates a second open voltage at said second measurement time by multiplying the sum of said external impedance and said internal impedance by the discharge current measured by said current sensing section, and calculates a recovered capacity of said secondary battery based on a first open voltage at said first measurement time, said second open voltage and said discharge capacity reference value.
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12. A degradation measurement method comprising:
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holding in advance the value of an external impedance present in a discharge path outside a secondary battery; discharging said secondary battery from a first measurement time to a second measurement time at which an integrated discharge capacity based on a measured discharge current becomes equal to a predetermined discharge capacity reference value; calculating an internal impedance present in said secondary battery at said second measurement time based on a voltage measured by said battery sensing section, and calculating a second open voltage at said second measurement time by multiplying the sum of said external impedance and said internal impedance by the measured discharge current; and calculating a recovered capacity of said secondary battery based on a first open voltage at said first measurement time, said second open voltage and said discharge capacity reference value.
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13. (canceled)
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14. A computer-readable recording medium having recorded therein a program for causing a computer to execute the steps of:
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holding in advance the value of an external impedance present in a discharge path outside a secondary battery; discharging said secondary battery from a first measurement time to a second measurement time at which an integrated discharge capacity based on a measured discharge current becomes equal to a predetermined discharge capacity reference value; calculating an internal impedance present in said secondary battery at said second measurement time based on a voltage measured by said battery sensing section, and calculating a second open voltage at said second measurement time by multiplying the sum of said external impedance and said internal impedance by the measured discharge current; and calculating a recovered capacity of said secondary battery based on a first open voltage at said first measurement time, said second open voltage and said discharge capacity reference value.
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Specification