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US 11,112,461 B2Granted
Method for estimating state of charge of energy storage device
AssigneeLG Chem, Ltd.
InventorsBo Mi Lim, Won Tae Joe
Life of this patent
Estimating the term…
Abstract
A method for estimating a state of charge of an energy storage system using a voltage modeling technique in which different parameters are used according to a charge/discharge state.
Claims15
A method for estimating a state of charge (SOC) of an energy storage system (ESS), the method comprising:
- a first step of measuring a current, voltage, and temperature of the energy storage system;
- a second step of determining a charge/discharge state on the basis of the current and voltage measured in the first step;
- a third step of deriving a state of charge (SOC) parameter according to the charge state or discharge state determined in the second step;
- and
- a fourth step of estimating the state of charge (SOC) of the energy storage system on the basis of the state of charge (SOC) parameter derived in the third step,
- wherein the third step of deriving the state of charge (SOC) parameter includes:
- modeling the energy storage system using an R-C circuit;
- and
- deriving the state of charge (SOC) parameter using the following equations:
- V
- 1
- '
-
- (
- t
- )
- =
- -
- 1
- R
- 1
-
- C
- 1
-
- V
- 1
-
- (
- t
- )
- -
- 1
- C
- 1
-
- i
-
- (
- t
- )
- +
- 1
- C
- 1
-
- w
- 1
-
- (
- t
- )
- ,
- and
-
-
- V
- 1
-
- (
- t
- )
- =
- V
- 1
- -
- R
- 0
-
- i
-
- (
- t
- )
- +
- v
-
- (
- t
- )
- ,
- and
- wherein R1 and C1 are polarization components, w1(t) is a value for compensating for a measurement error, R0 is an internal resistance component of the energy storage system, i(t) is a current measured in the R-C circuit at a time (t), and V1 denotes a polarization voltage, and v(t) is a value for compensating for a measurement error.
80 more elements
A method for estimating a state of charge (SOC) of an energy storage system (ESS), the method comprising:
- a state measurement step of measuring a current, voltage, and temperature of the energy storage system;
- a state-of-charge (SOC) estimation step of estimating states of charge (SOCs) respectively based on a current integrating method and a voltage modeling technique by applying the current, voltage, and temperature measured in the state measurement step to the current integrating method and the voltage modeling technique;
- an error range comparison step of comparing a difference between the state of charge of the current integrating method and the state of charge of the voltage modeling technique estimated in the state-of-charge (SOC) estimation step to determine whether the difference exceeds a predetermined error range;
- and
- a final state-of-charge (SOC) calculation step of calculating, when the difference between the state of charge (SOC) of the current integrating method and the state of charge (SOC) of the voltage modeling technique in the error range comparison step, a final state of charge (SOC) by applying a predetermined weight to the state of charge of the current integrating method and the state of charge of the voltage modeling technique,
- wherein the applying the predetermined weight to the state of charge of the current integrating method and the state of charge of the voltage modeling technique includes:
- applying an initial ratio between the state of charge (SOC) of the current integrating method and the state of charge (SOC) of the voltage modeling technique;
- and
- adjusting the ratio between the state of charge (SOC) of the current integrating method and the state of charge (SOC) of the voltage modeling technique to the predetermined weight in response to the difference between the state of charge of the current integrating method and the state of charge of the voltage modeling technique exceeding the predetermined error range.
6 more elements
A device for estimating a state of charge (SOC) of an energy storage system (ESS), the device comprising:
- a state measurement unit configured to measure a current, voltage, and temperature of the energy storage system;
- a state-of-charge (SOC) estimation unit configured to estimate states of charge (SOCs) respectively based on a current integrating method and a voltage modeling technique by applying the current, voltage, and temperature measured in the state measurement unit to the current integrating method and the voltage modeling technique;
- an error range comparison unit configured to compare a difference between the state of charge (SOC) of the current integrating method and the state of charge (SOC) of the voltage modeling technique estimated in the state-of-charge (SOC) estimation unit to determine whether the difference exceeds a predetermined error range;
- a final state-of-charge (SOC) calculation unit configured to calculate, when the difference between the state of charge of the current integrating method and the state of charge of the voltage modeling technique is determined to exceed the predetermined error range in the error range comparison unit, a final state of charge (SOC) by applying a predetermined weight to the state of charge of the current integrating method and the state of charge of the voltage modeling technique;
- and
- a memory configured to store each state of charge (SOC) estimated in the state-of-charge (SOC) estimation unit,
- wherein the applying the predetermined weight to the state of charge of the current integrating method and the state of charge of the voltage modeling technique includes:
- applying an initial ratio between the state of charge (SOC) of the current integrating method and the state of charge (SOC) of the voltage modeling technique;
- and
- adjusting the ratio between the state of charge (SOC) of the current integrating method and the state of charge (SOC) of the voltage modeling technique to the predetermined weight in response to the difference between the state of charge of the current integrating method and the state of charge of the voltage modeling technique exceeding the predetermined error range.
7 more elements
Dependencies are inferred from the claim text.