Method of determining the energy capacity of a battery
First Claim
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1. A method of determining the available energy of a battery comprising:
- measuring a first open circuit voltage of said battery to correlate to and determine a first state of charge;
changing a level of energy available in said battery by a measured amount;
measuring a second open circuit voltage of said battery after changing the level of energy to determine a second state of charge; and
dividing the measured amount of energy change in said battery by the calculated change in the state of charge from the first state of charge to the second state of charge to determine the available energy capacity of said battery;
wherein the step of changing the level of energy includes a discharge event, and the discharge event occurs at a current having a generally unvarying rate.
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Abstract
A method of determining the available energy of a battery provides for measuring first and second open circuit voltage of the battery with a change of energy level occurring therebetween. The two open circuit voltages are correlated to a state of charge level and the measured amount of change of energy is divided by the change of the state of charge.
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Citations
15 Claims
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1. A method of determining the available energy of a battery comprising:
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measuring a first open circuit voltage of said battery to correlate to and determine a first state of charge; changing a level of energy available in said battery by a measured amount; measuring a second open circuit voltage of said battery after changing the level of energy to determine a second state of charge; and dividing the measured amount of energy change in said battery by the calculated change in the state of charge from the first state of charge to the second state of charge to determine the available energy capacity of said battery; wherein the step of changing the level of energy includes a discharge event, and the discharge event occurs at a current having a generally unvarying rate. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of determining the available energy of a battery comprising:
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measuring a first open circuit voltage of said battery to correlate to and determine a first state of charge; changing a level of energy available in said battery by a measured amount; measuring a second open circuit voltage of said battery after changing the level of energy to determine a second state of charge; and dividing the measured amount of energy change in said battery by the calculated change in the state of charge from the first state of charge to the second state of charge to determine the available energy capacity of said battery wherein the step of changing the level of energy comprises a charging event, and the charging event uses an overvoltage to charge the battery until a battery charge current attains a predetermined low current value being at a generally unvarying rate, said predetermined low current value being one of; (i) substantially three amps, and (ii) greater than zero amps and less than three amps. - View Dependent Claims (8)
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9. A method of calculating a composite value for the available energy of a battery, comprising:
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determining a first value for the available energy of the battery using a first methodology; determining a second value for the available energy of the battery using a second methodology different from the first methodology; determining a third value for the available energy of the battery using a third methodology different from the first methodology and the second methodology; and calculating the composite value; wherein the composite value is in mathematical relation to the first and the second and the third value, and the first and the second and the third methodology each include; measuring a first open circuit voltage of said battery to correlate to and determine a first state of charge; changing a level of energy available in said battery by a measured amount; measuring a second open circuit voltage of said battery after changing the level of energy to determine a second state of charge; dividing the measured amount of energy change in said battery by the calculated change in the state of charge from the first state of charge to the second state of charge to determine the available energy capacity of said battery. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification