METHOD FOR DETERMINING THE STATE OF HEALTH OF A BATTERY
First Claim
1. A method for determining the state of health (SOH) of a battery comprising at least one rechargeable cell, the method including the steps of:
- determining a state of charge (SOC) for at least one cell;
determining in real time an impedance of at least one cell (Rmes,n);
determining at least one confidence coefficient accounting on reliability of the impedance as a function of at least one variable selected from current, temperature or state of charge of the at least one rechargeable cell, or the derivatives or integrals thereof with respect to time;
determining in real time the state of health of the battery at a given point in time (SOHn), using the state of health of the battery at a preceding point in time (SOHn-1) corrected as a function of said impedance at the given point in time (Rmes,n) and weighted by the at least one confidence coefficient.
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Accused Products
Abstract
A method for determining the state of health (SOH) of a battery is provided in which cell impedance is determined continuously, and including determining one or more confidence coefficients that depend on one or several variables selected from cell current, temperature or state of charge or their derivatives or integrals with respect to time, and continuously determining the state of health of the battery at a given point in time, using the state of health of the battery at a preceding point in time corrected as a function of cell impedance determined at the given point in time and weighted by the confidence coefficient or coefficients. The method provides a reliable way of determining the state of health of the battery with greater stability and robustness than existing methods.
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Citations
18 Claims
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1. A method for determining the state of health (SOH) of a battery comprising at least one rechargeable cell, the method including the steps of:
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determining a state of charge (SOC) for at least one cell; determining in real time an impedance of at least one cell (Rmes,n); determining at least one confidence coefficient accounting on reliability of the impedance as a function of at least one variable selected from current, temperature or state of charge of the at least one rechargeable cell, or the derivatives or integrals thereof with respect to time; determining in real time the state of health of the battery at a given point in time (SOHn), using the state of health of the battery at a preceding point in time (SOHn-1) corrected as a function of said impedance at the given point in time (Rmes,n) and weighted by the at least one confidence coefficient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An electronic system for managing state of health (SOH) of a battery comprising at least one rechargeable cell, the system including:
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means for measuring in real time an impedance (Rmes,n) of at least one cell; electronic means adapted to—
determine a state of charge (SOC) for at least one cell;determine at least one confidence coefficient accounting on reliability of the impedance as a function of at least one variable selected from current, temperature or state of charge of the at least one rechargeable cell, or the derivatives or integrals thereof with respect to time; determine in real time the state of health of the battery at a given point in time (SOHn), using the state of health of the battery at a preceding point in time (SOHn-1) corrected as a function of said impedance at the given point in time (Rmes,n) and weighted by the at least one confidence coefficient. - View Dependent Claims (16, 17)
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18. A battery comprising:
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at least one electrochemical cell; an electronic system including; means for measuring in real time an impedance (Rmes,n) of at least one cell; means for measuring in real time temperature of at least one cell; electronic means adapted to determine a state of charge (SOC) for at least one cell; determine at least one confidence coefficient accounting on reliability of the impedance as a function of at least one variable selected from current, temperature or state of charge of the at least one rechargeable cell, or the derivatives or integrals thereof with respect to time; determine in real time the state of health of the battery at a given point in time (SOHn), using the state of health of the battery at a preceding point in time (SOHn-1) corrected as a function of said impedance at the given point in time (Rmes,n) and weighted by the at least one confidence coefficient.
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Specification