Systems and methods for determining battery state of charge
First Claim
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1. A system for determining the state of charge (SOC) of a lithium battery comprising:
- a controller measuring an initial open circuit voltage (OCV) at a first time;
the controller determining the SOC of the battery from the measurement of the OCV at the first time;
a power source charging the battery at a predetermined DC current;
the controller determining a subsequent SOC of the battery at a second time based on charging current and the amount of time the battery is being charged;
the controller utilizing the subsequent SOC of the battery to determine a subsequent OCV of the battery;
the controller utilizing the subsequent OCV to determine a corresponding impedance of the battery;
a memory coupled to the controller for storing correspondence between an impedance of the battery and corresponding SOC of the battery; and
the controller, during a discharge time, utilizing the correspondence of the SOC of the battery and the impedance of the battery, which was determined during battery charging, to determine a discharge SOC by determining the present impedance of the battery through measurement or prediction.
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Abstract
Systems (50, 200) and methods for determining a state of charge of a battery (52, 102, 150, 202) are provided. The system (50, 200) includes a power source (56, 206) configured to provide a charging current to a battery (52, 102, 150, 202). A controller (54, 104, 204) is included and configured to determine a state of charge of the battery (52, 102, 150, 202) based on impedance of a battery (52, 102, 150, 202) during a discharge time period based on an impedance and a state of charge relationship of a battery (52, 102, 150, 202) during a charge time period.
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Citations
21 Claims
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1. A system for determining the state of charge (SOC) of a lithium battery comprising:
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a controller measuring an initial open circuit voltage (OCV) at a first time; the controller determining the SOC of the battery from the measurement of the OCV at the first time; a power source charging the battery at a predetermined DC current; the controller determining a subsequent SOC of the battery at a second time based on charging current and the amount of time the battery is being charged; the controller utilizing the subsequent SOC of the battery to determine a subsequent OCV of the battery; the controller utilizing the subsequent OCV to determine a corresponding impedance of the battery; a memory coupled to the controller for storing correspondence between an impedance of the battery and corresponding SOC of the battery; and the controller, during a discharge time, utilizing the correspondence of the SOC of the battery and the impedance of the battery, which was determined during battery charging, to determine a discharge SOC by determining the present impedance of the battery through measurement or prediction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 18, 19)
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14. A method for determining the state of charge (SOC) of a lithium battery comprising:
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measuring an initial open circuit voltage (OCV) at a first time; determining the SOC of the battery from the measurement of the OCV at the first time; charging the battery with a predetermined DC current; determining a subsequent SOC of the battery at a second time based on charging current and the amount of time the battery is being charged; utilizing the subsequent SOC of the battery to determine a subsequent OCV of the battery; utilizing the subsequent OCV to determine a corresponding impedance of the battery; storing correspondence between an impedance of the battery and corresponding SOC of the battery in a memory; and during a discharge time, utilizing the correspondence of the SOC of the battery and the impedance of the battery, which was determined during battery charging, to determine a discharge SOC by determining the present impedance of the battery through measurement or prediction. - View Dependent Claims (15, 16, 17, 20, 21)
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Specification