An assembly capable of delivering an output current I s comprising: - N cells (B i) for storing or producing electrical energy of rank i, with N ≥ 2, each cell comprising an elementary cell or an elementary assembly of elementary cells (CE ij) placed in series and/or in parallel, each cell for storing or producing electrical energy being capable of providing a maximum current I max,i at each instant t; - a circuit for managing said cells (B i) for storing or producing electrical energy, characterised in that said cells for storing or producing electrical energy are classified according to their rank i in decreasing priority of use, said management circuit comprises means in discharging mode for addressing at least the cell for storing or producing electrical energy of rank 1 or cells for storing or producing electrical energy according to their rank i and according to the following criteria: - the cell for storing or producing electrical energy of rank 1 is addressed alone as long as it is capable of providing the output current I s, with I s < I max1; - the cell (B i) for storing or producing electrical energy of rank 1 is addressed with, in addition, a number k of cells (B i) for storing or producing electrical energy successively addressed according to their rank i so as to provide, at each instant in discharging mode, the current I s, the number k being such that 2 < k ≤ N and meets the following conditions: ∑ i = 1 k − 1 I max, i < l s and ∑ i = 1 k I max, i ≥ l s; - said circuit for managing said cells (B i) for storing or producing electrical energy comprising: - blocks (M i) of rank i, each cell (B i) for storing or producing electrical energy being coupled to a block (M i), each cell (B i) coupled to a block (M i) being capable of delivering an output current I i; - all said blocks (M i) generating the output current I s equal to the sum of the output currents I i, said blocks (M i) selecting: the first cell for storing or producing electrical energy until its total depletion, without exceeding the current value I max,1, then the second cell for storing or producing electrical energy until its total depletion without exceeding the current value I max,2,..., then the N th cell for storing or producing electrical energy. - N cells (B i) for storing or producing electrical energy of rank i, with N ≥ 2, each cell comprising an elementary cell or an elementary assembly of elementary cells (CE ij) placed in series and/or in parallel, each cell for storing or producing electrical energy being capable of providing a maximum current I max,i at each instant t; - a circuit for managing said cells (B i) for storing or producing electrical energy, - the cell for storing or producing electrical energy of rank 1 is addressed alone as long as it is capable of providing the output current I s, with I s < I max1; - the cell (B i) for storing or producing electrical energy of rank 1 is addressed with, in addition, a number k of cells (B i) for storing or producing electrical energy successively addressed according to their rank i so as to provide, at each instant in discharging mode, the current I s, the number k being such that 2 < k ≤ N and meets the following conditions: ∑ i = 1 k − 1 I max, i < l s and ∑ i = 1 k I max, i ≥ l s; - said circuit for managing said cells (B i) for storing or producing electrical energy comprising: - blocks (M i) of rank i, each cell (B i) for storing or producing electrical energy being coupled to a block (M i), each cell (B i) coupled to a block (M i) being capable of delivering an output current I i; - all said blocks (M i) generating the output current I s equal to the sum of the output currents I i, said blocks (M i) selecting: the first cell for storing or producing electrical energy until its total depletion, without exceeding the current value I max,1, then the second cell for storing or producing electrical energy until its total depletion without exceeding the current value I max,2,..., then the N th cell for storing or producing electrical energy.