Battery state estimator with overpotential-based variable resistors
AssigneeGM Global Technology Operations LLC
InventorsBrian J. Koch, Krishnan S. Hariharan, Senthil K. Vadivelu
Life of this patent
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Abstract
A battery model and equivalent circuit that includes an ohmic resistance, a first RC-pair that models a battery cell charge transfer reaction and double layer processes and a second RC-pair that models battery cell diffusion. Each of the ohmic resistance, the charge transfer reaction resistance and the diffusion resistance in the model are variable resistances, where each resistance changes in response to a change in voltage potential across the resistance.
Claims20
A circuit model for a battery comprising:
- a voltage source;
- an ohmic variable resistor electrically coupled in series with the voltage source;
- a first RC-pair electrically coupled in series with the ohmic variable resistor and the voltage source, said first RC-pair including a first capacitor and first variable resistor electrically coupled in parallel;
- and
- a second RC-pair electrically coupled in series with the first RC-pair, the ohmic variable resistor and the voltage source, said second RC-pair including a second capacitor and a second variable resistor electrically coupled in parallel, wherein each of the ohmic variable resistor, the first variable resistor and the second variable resistor have a variable resistance that changes in response to a voltage potential across each resistor.
A circuit model for a battery comprising:
- a voltage source;
- an ohmic variable resistor electrically coupled in series with the voltage source;
- and
- at least one RC-pair electrically coupled in series with the ohmic variable resistor and the voltage source, said at least one RC-pair including a capacitor and an RC-pair variable resistor electrically coupled in parallel, wherein each of the ohmic variable resistor and the RC-pair variable resistor have a variable resistance that changes in response to a voltage potential across the each resistor.
A circuit model for a vehicle battery comprising:
- a voltage source;
- an ohmic variable resistor electrically coupled in series with the voltage source, wherein a resistance of the ohmic variable resistor is based on the equation:
- R=r0V1-r1
- where R is the resistance of the ohmic variable resistor, Vis the cell voltage across the ohmic variable resistor, and r0 and r1 are predetermined constant resistances;
- a first RC-pair electrically coupled in series with the ohmic variable resistor and the voltage source, said first RC-pair including a first capacitor and a first variable resistor electrically coupled in parallel, wherein a resistance of the first variable resistor is based on the equation:
- R
- 1
- =
- r
- 10
- cosh
-
- (
- F
- 2
-
-
- R
- g
-
- T
-
- V
- 1
- )
- where R1 is the resistance of the first variable resistor, V1 is the voltage across the first variable resistor, F is Faradays constant, T is temperature of the battery, Rg is the ideal gas constant and r10 is a predetermined constant resistance;
- and
- a second RC-pair electrically coupled in series with the first RC-pair, the ohmic variable resistor and the voltage source, said second RC-pair including a second capacitor and a second variable resistor electrically coupled in parallel, wherein a resistance of the second variable resistor is based on the equation:
- R2=r20V21-r21
- where R2 is the resistance of the second variable resistor, V2 is the voltage across the second variable resistor, and r20 and r21 are predetermined constant resistances.
Dependencies are inferred from the claim text.