Systems and methods for estimating battery pack capacity
First Claim
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1. A method of estimating a capacity of a battery pack, the method comprising:
- receiving, by battery control electronics associated with the battery pack from a voltage sensor configured to measure a terminal voltage of the battery pack, battery pack terminal voltage measurement information;
calculating, by the battery control electronics, skewness information based on the battery pack terminal voltage measurement information, the skewness information defining a relationship between the battery pack terminal voltage measurement information and a plurality of states of charge of the battery pack;
identifying, by the battery control electronics, a first inflection point in the skewness information;
determining, by the battery control electronics, a first state of charge of the battery pack associated with the first inflection point;
determining, by the battery control electronics, a second state of charge of the battery pack;
determining, by the battery control electronics, a net charge difference of the battery pack between the first state of charge and the second state of charge;
determining, by the battery control electronics, an estimated capacity of the battery pack based on the net charge difference, the first state of charge, and the second state of charge; and
controlling, by the battery control electronics, an operation of the battery pack based on the estimated capacity of the battery pack, wherein the operation comprises at least one of a charging operation, a discharging operation, and a balancing operation.
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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, by battery control electronics associated with the battery pack from a voltage sensor configured to measure a terminal voltage of the battery pack, battery pack terminal voltage measurement information; calculating, by the battery control electronics, skewness information based on the battery pack terminal voltage measurement information, the skewness information defining a relationship between the battery pack terminal voltage measurement information and a plurality of states of charge of the battery pack; identifying, by the battery control electronics, a first inflection point in the skewness information; determining, by the battery control electronics, a first state of charge of the battery pack associated with the first inflection point; determining, by the battery control electronics, a second state of charge of the battery pack; determining, by the battery control electronics, a net charge difference of the battery pack between the first state of charge and the second state of charge; determining, by the battery control electronics, an estimated capacity of the battery pack based on the net charge difference, the first state of charge, and the second state of charge; and controlling, by the battery control electronics, an operation of the battery pack based on the estimated capacity of the battery pack, wherein the operation comprises at least one of a charging operation, a discharging operation, and a balancing operation. - 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, the skewness information defining a relationship between the battery pack terminal voltage measurement information and a plurality of states of charge of the battery pack; 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)
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17. A non-transitory computer-readable medium comprising instructions that, when executed by a processor included in battery control electronics associated with a battery pack, cause the processor to perform a method for estimating a capacity of the battery pack comprising:
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receiving, from a voltage sensor configured to measure a terminal voltage of the battery pack, battery pack terminal voltage measurement information; calculating skewness information based on the battery pack terminal voltage measurement information, the skewness information defining a relationship between the battery pack terminal voltage measurement information and a plurality of states of charge of the battery pack; 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; 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; and controlling, by the battery control electronics, an operation of the battery pack based on the estimated capacity of the battery pack, wherein the operation comprises at least one of a charging operation, a discharging operation, and a balancing operation. - View Dependent Claims (18, 19)
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Specification