AUTOMATIC METHOD FOR ESTIMATING THE STATE OF CHARGE OF A CELL OF A BATTERY
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Abstract
A method for estimating state-of-charge of a battery cell includes suppressing full execution of a capacitance-estimation algorithm for as long as a parameter does not exceed a certain threshold. The parameter is either a measured voltage value across the cell'"'"'s terminals, the cell'"'"'s estimated state-of-charge, or an amount of charge passing in or out of the cell during some interval. A battery-management system triggers full execution when the parameter falls below the threshold, or, if the parameter is the amount of charge passing, when it rises above the threshold.
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18 Claims
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1-9. -9. (canceled)
- 10. A method comprising automatically estimating state-of-charge of a battery'"'"'s cell, wherein automatically estimating state-of-charge comprises, at each of a plurality of first instants k, acquiring a measured voltage yk and a measured current ik, wherein said measured voltage is a voltage across said cell'"'"'s terminals, and wherein said measured current is a current selected from the group consisting of a current that charges said cell and a current that discharges said cell, estimating said cell'"'"'s state-of-charge SOCk based at least in part on said measured voltage, said measured current, and a capacitance Cn,k3 of said cell, said capacitance being indicative of an amount of energy that can be stored by said cell at a second instant k3 from a plurality of second instants, said second instants occurring less frequently than said first instants, wherein said second instant is a second instant that is closer to said first instant k than all other second instants in said plurality of second instants, said capacitance having been estimated at said second instant k3, wherein estimating said cell'"'"'s state-of-charge SOCk comprises causing an electronic processor to inhibit full execution of an algorithm for estimating capacitance Cn,k3 of said cell based at least in part on current ik3 measured at a second instant k3 when a first condition is met, and causing said electronic processor to trigger full execution of said algorithm when any one of a second condition, a third condition, and a fourth condition is met, wherein said first condition is that a value of a parameter has not crossed a first preset threshold, said parameter being chosen from the group consisting of said measured voltage yk, said estimate of said state-of-charge SOCk, and an amount Qk of charge that has passed through said cell between said instant k and a preceding instant, wherein said second condition is that said parameter has dropped below said first preset threshold and that said parameter is said measured voltage yk, wherein said third condition is that said parameter has dropped below said first preset threshold and that said parameter is said estimate of said state-of-charge SOCk, and wherein said fourth condition is that said parameter has risen above said first preset threshold and that said parameter is said amount Qk of charge that has passed through said cell between said instant k and a preceding instant.
Specification