SYSTEMS AND METHODS FOR ESTIMATING BATTERY PACK CAPACITY
First Claim
1. A method of estimating a capacity of a battery pack, the method comprising:
- receiving battery pack terminal voltage measurement information;
calculating skewness information based on the battery pack terminal voltage measurement information;
identifying a first inflection point in the skewness information;
determining a first state of charge of the battery pack associated with the first inflection point;
determining a second state of charge of the battery pack;
determining a net charge difference of the battery pack between the first state of charge and the second state of charge; and
determining an estimated capacity of the battery pack based on the net charge difference, the first state of charge, and the second state of charge.
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Abstract
System and methods for estimating a capacity of a battery are presented. A measure of data skewness may be calculated from a battery system terminal voltage measurement. Inflection points in the data skewness of the terminal voltage measurement may align with transition points associated with a battery system. These transitions points may be associated with known SOCs determined from testing and/or characterization of the battery system. Using the detected transitions and associated SOCs and an indication of an accumulated charge provided to/from the battery between the transitions, an estimated capacity of the battery system may be determined.
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Citations
19 Claims
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1. A method of estimating a capacity of a battery pack, the method comprising:
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receiving battery pack terminal voltage measurement information; calculating skewness information based on the battery pack terminal voltage measurement information; identifying a first inflection point in the skewness information; determining a first state of charge of the battery pack associated with the first inflection point; determining a second state of charge of the battery pack; determining a net charge difference of the battery pack between the first state of charge and the second state of charge; and determining an estimated capacity of the battery pack based on the net charge difference, the first state of charge, and the second state of charge. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system comprising:
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a battery pack; a voltage sensor configured to measure a terminal voltage of the battery pack; and battery control electronics communicatively coupled to the voltage sensor, the battery control electronics being configured to; receive battery pack terminal voltage measurement information from the voltage sensor; calculate skewness information based on the battery pack terminal voltage measurement information; identify a first inflection point in the skewness information; determine a first state of charge of the battery pack associated with the first inflection point; determine a second state of charge of the battery pack; determine a net charge difference of the battery pack between the first state of charge and the second state of charge; and determine an estimated capacity of the battery pack based on the net charge difference, the first state of charge, and the second state of charge. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 18, 19)
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17. A non-transitory computer-readable medium comprising instructions that, when executed by a processor, cause the processor to perform a method for estimating a capacity of a battery pack comprising:
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receiving battery pack terminal voltage measurement information; calculating skewness information based on the battery pack terminal voltage measurement information; identifying a first inflection point in the skewness information; determining a first state of charge of the battery pack associated with the first inflection point; determining a second state of charge of the battery pack; determining a net charge difference of the battery pack between the first state of charge and the second state of charge; and determining an estimated capacity of the battery pack based on the net charge difference, the first state of charge, and the second state of charge.
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Specification