Method and apparatus for measuring the aging state of batteries of electrochemical accumulators

Abstract

Method and apparatus for measuring the aging state (SOL) of batteries of electrochemical accumulators in which the battery is first characterized (step of construction of the curve VOC-SOC) by means of a correlation curve between the measurable value of the open circuit voltage at rest (arithmetic mean between the voltages of all cells) at the electrodes (VOC) and the state of charge (SOC): this correlation curve is invariant with respect to the aging of the battery. The current SOL value is then calculated (SOL assessment step during normal battery use) starting from the direct measurement of the open circuit voltage value at rest at the end of normal battery use, and using for the calculation the measurement of the charge delivered during use, starting from a condition in which the battery was in a known state of charge. The state of charge of a battery is assumed to be known when it has been at rest for a sufficient time, that is, for a time at least equal to the minimum rest period (for example 60 minutes) such that at the end of it the voltage can be considered completely stabilized, and for it the SOC is determined by the correlation of the same with the VOC in the construction step.

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