BATTERY STATE-OF-CHARGE ESTIMATION METHOD AND BATTERY MANAGEMENT SYSTEM
First Claim
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1. A battery state-of-charge (SOC) estimation method comprising:
- an SOC table creation step of dividing the entire area of a two-dimensional coordinate system representing a relation between battery open-circuit voltages and battery SOCs into a plurality of steps at a plurality of different temperatures at a time point when a battery is charged or discharged, and storing function information representative of the relation between battery open-circuit voltages and battery SOCs for each step in an SOC table;
an SOC calculation step of applying an initial SOC extracted by using the function information stored in the SOC table, parameters of elements used in a battery equivalent model, an open-circuit voltage of the battery, and an amount of current inputted to or outputted from the battery to a current integral equation, and calculating an SOC of the battery;
an SOC comparison step of extracting an SOC corresponding to the open-circuit voltage applied at the SOC calculation step using the function information stored in the SOC table, and comparing the extracted SOC and the calculated SOC; and
a processing step of displaying the calculated SOC when a difference between the extracted SOC and the calculated SOC is smaller than a critical value.
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Abstract
Provided are a battery state-of-charge (SOC) estimation method and a battery management system which are capable of estimating an SOC using an inexpensive processor and a small-capacity memory. The SOC estimation method includes an SOC table creation step, an SOC calculation step, an SOC comparison step, and a processing step. The battery management system includes a battery, a sensing resistor, a control switch unit, and a processor.
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Citations
18 Claims
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1. A battery state-of-charge (SOC) estimation method comprising:
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an SOC table creation step of dividing the entire area of a two-dimensional coordinate system representing a relation between battery open-circuit voltages and battery SOCs into a plurality of steps at a plurality of different temperatures at a time point when a battery is charged or discharged, and storing function information representative of the relation between battery open-circuit voltages and battery SOCs for each step in an SOC table; an SOC calculation step of applying an initial SOC extracted by using the function information stored in the SOC table, parameters of elements used in a battery equivalent model, an open-circuit voltage of the battery, and an amount of current inputted to or outputted from the battery to a current integral equation, and calculating an SOC of the battery; an SOC comparison step of extracting an SOC corresponding to the open-circuit voltage applied at the SOC calculation step using the function information stored in the SOC table, and comparing the extracted SOC and the calculated SOC; and a processing step of displaying the calculated SOC when a difference between the extracted SOC and the calculated SOC is smaller than a critical value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A battery management system comprising:
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a sensing resistor connected to one end of a battery; a control switch unit configured to transmit a current supplied from a current source to the battery or transmit a current outputted from the battery to a load, in response to a control signal; and a processor configured to generate the control signal, calculate parameters of elements applied to an equivalent model of the battery using a measured temperature of the battery, a current of the battery, and an open-circuit voltage of the battery, and create and store an SOC table using the temperature and the open-circuit voltage of the battery. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification