Method for estimating the state of health of an electrochemical cell for storing electrical energy
AssigneeRENAULT s.a.s.
InventorsBruno Delobel, Antoine Saint-Marcoux
Life of this patent
Estimating the term…
Abstract
A method for estimating a state of health of an electrochemical cell for storing electrical energy includes applying at least one current strength peak to the cell, the current peak passing through the cell, measuring a variation, as a function of a time t elapsed after the application of the current peak, of voltage U at the terminals of the cell, and calculating at least one coefficient αI1 and at least one coefficient U0,I1 such that the function √{square root over (t)}→αI1×√{square root over (t)}+U0,I1 is a linear approximation of the variation of the voltage U as a function of √{square root over (t)} for √{square root over (t)}≥C, where C>0. The method is used in electrical or hybrid vehicles.
Claims8
A method for estimating a state of health of an electrochemical cell for storing electrical energy, the method comprising:
- applying to the cell at least one current peak of intensity I1, the current peak flowing through the cell;
- measuring a variation, as a function of a time t that has passed after an application of the current peak, of a voltage U across terminals of the cell;
- calculating at least one coefficient αI1 and at least one coefficient U0,I1 such that U=αI1×√{square root over (t)}+U0,I1 is a linear approximation of the variation of the voltage U as a function of √{square root over (t)}, where √{square root over (t)}≥1;
- calculating a coefficient β such that −U/√{square root over (t)}=β×I is a linear approximation of a variation of ΔU/√{square root over (t)} as a function of I, wherein a plurality of current peaks of intensities (In)n≥2 are applied to the cell (I1, I2, I3, I4, I5);
- estimating the state of health of the cell based on either of the coefficients calculated in the calculating;
- and
- detecting a fault with connection hardware of the cell when at least one of the coefficients is increasing above a predetermined amount with respect to a value of the coefficient at a beginning of life of the cell.
Dependencies are inferred from the claim text.