Methods and systems for thermodynamic evaluation of battery state of health
First Claim
1. A method of charging an electrochemical cell comprising a host material, the method comprising the steps of:
- characterizing the state of health of the electrochemical cell;
selecting a charging voltage, current or voltage and current according to the characterized state of health of the electrochemical cell; and
providing the selected voltage, current or voltage and current to electrodes of the electrochemical cell to charge the electrochemical cellwherein the step of characterizing the state of health of the electrochemical cell comprises the steps of;
determining a change in Gibbs Free Energy (Δ
G), a change in Entropy (Δ
S), a change in Enthalpy (Δ
H) or any combination thereof of the electrochemical cell for a plurality of selected electrochemical cell compositions;
determining states of charge of the electrochemical cell for each of the plurality of selected electrochemical cell compositions;
identifying the states of charge and Δ
G, Δ
S, Δ
H or any combination thereof corresponding to an event or condition of the electrochemical cell; and
comparing the Δ
G, Δ
S, Δ
H or any combination thereof corresponding to the event or condition of the electrochemical cell to reference Δ
G, Δ
S, Δ
H or any combination thereof corresponding to the event or condition of a reference electrochemical cell.
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Accused Products
Abstract
Described are systems and methods for accurately characterizing thermodynamic and materials properties of electrodes and battery systems and for characterizing the state of health of electrodes and battery systems. Measurement of physical attributes of electrodes and batteries corresponding to thermodynamically stabilized electrode conditions permit determination of thermodynamic parameters, including state functions such as the Gibbs free energy, enthalpy and entropy of electrode/electrochemical cell reactions, that enable prediction of important performance attributes of electrode materials and battery systems, such as energy, power density, current rate, cycle life and state of health. Also provided are systems and methods for charging a battery according to its state of health.
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Citations
16 Claims
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1. A method of charging an electrochemical cell comprising a host material, the method comprising the steps of:
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characterizing the state of health of the electrochemical cell; selecting a charging voltage, current or voltage and current according to the characterized state of health of the electrochemical cell; and providing the selected voltage, current or voltage and current to electrodes of the electrochemical cell to charge the electrochemical cell wherein the step of characterizing the state of health of the electrochemical cell comprises the steps of; determining a change in Gibbs Free Energy (Δ
G), a change in Entropy (Δ
S), a change in Enthalpy (Δ
H) or any combination thereof of the electrochemical cell for a plurality of selected electrochemical cell compositions;determining states of charge of the electrochemical cell for each of the plurality of selected electrochemical cell compositions; identifying the states of charge and Δ
G, Δ
S, Δ
H or any combination thereof corresponding to an event or condition of the electrochemical cell; andcomparing the Δ
G, Δ
S, Δ
H or any combination thereof corresponding to the event or condition of the electrochemical cell to reference Δ
G, Δ
S, Δ
H or any combination thereof corresponding to the event or condition of a reference electrochemical cell.- View Dependent Claims (2, 3, 4, 5)
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6. A method of charging an electrochemical cell comprising a host material, the method comprising the steps of:
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characterizing the state of health of the electrochemical cell; selecting a charging voltage, current or voltage and current according to the characterized state of health of the electrochemical cell; and providing the selected voltage, current or voltage and current to electrodes of the electrochemical cell to charge the electrochemical cell wherein when the characterized state of health corresponds to a first state of health of the electrochemical cell, a first charging voltage is selected and wherein when the characterized state of health corresponds to a second state of health of the electrochemical cell, a second charging voltage less than the first charging voltage is selected.
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7. A system for charging an electrochemical cell comprising a host material, the system comprising:
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means for delivering a voltage, current or voltage and current to electrodes of the electrochemical cell; means for characterizing a state of health of the electrochemical cell; and a control circuit for; receiving the characterized state of health; selecting a charging voltage, current or voltage and current according to the characterized state of health of the electrochemical cell; and controlling the means for delivering a voltage, current or voltage and current; wherein the means for delivering a voltage, current or voltage and current provide the selected voltage, current or voltage and current to the electrodes of the electrochemical cell to charge the electrochemical cell and the means for characterizing the state of health of the electrochemical cell comprises a system configured for performing a method comprising the steps of; determining a change in Gibbs Free Energy (Δ
G), a change in Entropy (Δ
S), a change in Enthalpy (Δ
H) or any combination thereof of the electrochemical cell for a plurality of selected electrochemical cell compositions;determining states of charge of the electrochemical cell for each of the plurality of selected electrochemical cell compositions; identifying the states of charge and Δ
G, Δ
S, Δ
H or any combination thereof corresponding to an event or condition of the electrochemical cell; andcomparing the Δ
G, Δ
S, Δ
H or any combination thereof corresponding to the event or condition of the electrochemical cell to reference Δ
G, Δ
S, Δ
H or any combination thereof corresponding to the event or condition of a reference electrochemical cell.- View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A system for charging an electrochemical cell comprising a host material, the system comprising:
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means for delivering a voltage, current or voltage and current to electrodes of the electrochemical cell; means for characterizing a state of health of the electrochemical cell; and a control circuit for; receiving the characterized state of health; selecting a charging voltage, current or voltage and current according to the characterized state of health of the electrochemical cell; and controlling the means for delivering a voltage, current or voltage and current; wherein the means for delivering a voltage, current or voltage and current provide the selected voltage, current or voltage and current to the electrodes of the electrochemical cell to charge the electrochemical cell and the means for characterizing the state of health of the electrochemical cell comprises a system configured for performing a method comprising the steps of; determining changes in entropy, enthalpy or free energy of the electrochemical cell for a plurality of selected electrochemical cell compositions; determining states of charge of the electrochemical cell for each of the plurality of selected electrochemical cell compositions; identifying the states of charge and changes in entropy, enthalpy or free energy corresponding to an event or condition of the electrochemical cell; and comparing the changes in entropy, enthalpy or free energy corresponding to the event or condition of the electrochemical cell to reference changes in entropy, enthalpy or free energy corresponding to the event or condition of a reference electrochemical cell.
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16. A system for charging an electrochemical cell comprising a host material, the system comprising:
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means for delivering a voltage, current or voltage and current to electrodes of the electrochemical cell; means for characterizing a state of health of the electrochemical cell; and a control circuit for; receiving the characterized state of health; selecting a charging voltage, current or voltage and current according to the characterized state of health of the electrochemical cell; and controlling the means for delivering a voltage, current or voltage and current; wherein the means for delivering a voltage, current or voltage and current provide the selected voltage, current or voltage and current to the electrodes of the electrochemical cell to charge the electrochemical cell and wherein the means for characterizing the state of health of the electrochemical cell comprises; a means for measuring open circuit voltages of the electrochemical cell as a function of time; a composition controller electrically connected to the electrochemical cell for establishing selected electrochemical cell compositions corresponding to different stoichiometries of a species incorporated with a host material of the electrochemical cell, the composition controller configured for establishing a plurality of the selected compositions; a temperature controller in thermal contact with the electrochemical cell for establishing a plurality of selected electrochemical cell temperatures for each of the selected compositions, thereby establishing a plurality of selected electrochemical cell temperature and composition combinations; and an open circuit voltage analyzer for receiving open circuit voltage measurements as a function of time from the means for measuring open circuit voltages and for identifying open circuit voltages for thermochemically stabilized conditions of the electrochemical cell for the selected electrochemical cell temperature and compositions combinations.
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Specification