Automatic method of determination of the state of charge of a battery comprising several electrical energy storage cells, these cells being electrically connected to one another between two electrical terminals of the battery, this method involving: a) the acquisition, at each time k and for each cell of the battery, of the measured value y k of the voltage between terminals of that cell, and the measured intensity ik of the charge or discharge current of that cell, b) at least at certain of these times k, the complete execution, by an electronic calculator and for at least one of the cells of the battery, of an algorithm to estimate the state of charge SOC k of this cell, as a function of the value y k and the intensity i k measured for that cell at that time k, and c) the determination (190, 192) of the state of charge of the battery from the states of charge estimated for each of the cells of this battery, characterized in that the method involves: - for each cell, calculating a difference in voltages between the value y k measured between the terminals of this cell at time k and a value y k-X measured between these same terminals at a previous time k-X, where X is a whole number equal to or greater than one, then - assigning to each cell a priority level, the priority level of a cell being higher as the voltage difference calculated for that cell is higher, - scheduling of times for refreshing the estimation of the state of charge of each cell as a function of the priority levels assigned to each of these cells, this scheduling involving the assigning, during a same time interval, a greater number of refresh times to the cells whose priority level is higher than the number of refresh times assigned to the cells whose priority level is lower, and - for each cell, fully executing the algorithm for estimation of the state of charge of that cell at each scheduled refresh time for that cell and inhibiting the full execution of this algorithm for estimation of its state of charge outside of the refresh times scheduled for that cell. a) the acquisition, at each time k and for each cell of the battery, of the measured value y k of the voltage between terminals of that cell, and the measured intensity ik of the charge or discharge current of that cell, b) at least at certain of these times k, the complete execution, by an electronic calculator and for at least one of the cells of the battery, of an algorithm to estimate the state of charge SOC k of this cell, as a function of the value y k and the intensity i k measured for that cell at that time k, and c) the determination (190, 192) of the state of charge of the battery from the states of charge estimated for each of the cells of this battery, - for each cell, calculating a difference in voltages between the value y k measured between the terminals of this cell at time k and a value y k-X measured between these same terminals at a previous time k-X, where X is a whole number equal to or greater than one, then - assigning to each cell a priority level, the priority level of a cell being higher as the voltage difference calculated for that cell is higher, - scheduling of times for refreshing the estimation of the state of charge of each cell as a function of the priority levels assigned to each of these cells, this scheduling involving the assigning, during a same time interval, a greater number of refresh times to the cells whose priority level is higher than the number of refresh times assigned to the cells whose priority level is lower, and - for each cell, fully executing the algorithm for estimation of the state of charge of that cell at each scheduled refresh time for that cell and inhibiting the full execution of this algorithm for estimation of its state of charge outside of the refresh times scheduled for that cell.