Charging circuit (200, 300, 400, 500) for an electrical energy storage system having n electrical energy storage units (R1, R2, R3) each having a first pole and a second pole, wherein n > 1, comprising - at least one first input and one second input for electrical connection to an energy source, - at least one first output and one second output for electrical connection to an electrical component, - at least n first pole connections and n second pole connections, wherein an i-th first pole connection is able to be electrically conductively connected to the first pole of the i-th electrical energy storage unit (R1, R2, R3) and an i-th second pole connection is able to be electrically conductively connected to the second pole of the i-th electrical energy storage unit (R1, R2, R3), - at least n first switches (S11, S12, S13), wherein a first connection of the i-th first switch (S11, S12, S13) is electrically conductively connected to the i-th first pole connection of the i-th electrical energy storage unit (R1, R2, R3), - at least n second switches (S21, S22, S23), wherein a first connection of the i-th second switch (S21, S22, S23) is electrically conductively connected to the i-th second pole connection of the i-th electrical energy storage unit (R1, R2, R3), - at least n-1 third switches (S31, S32), wherein a first connection of the k-th third switch (S31, S32) is electrically conductively connected to the first pole connection of the k-th electrical energy storage unit (R1, R2, R3) and a second connection of the k-th third switch (S31, S32) is electrically conductively connected to the second pole connection of the k+1-th electrical energy storage unit (R1, R2, R3), wherein n > 1 and i ≤ n, k < n are natural numbers, - at least one DC voltage converter, characterized in that the first output is electrically conductively connected to the second connection of the first switch, the second output is electrically conductively connected to the second connection of the first second switch, the first input is electrically conductively connected to the first connection of the n-th first switch (S12, S13), the second input is electrically conductively connected to the first connection of the first second switch and the first switches (S11, S12, S13), the second switches (S21, S22, S23) and the third switches (S31, S32) are connected in such a way that during the charging operation by means of an energy source connected to the first input and the second input an at least twice as high voltage level is applied between the first input and the second input compared to a voltage level between the first output and the second output, and wherein a first electrical input of the DC voltage converter is electrically conductively connected to the first input of the charging circuit, a second electrical input of the DC voltage converter is electrically conductively connected to the second input of the charging circuit, a first electrical output of the DC voltage converter is electrically conductively connected to the first output of the charging circuit (200, 300, 400, 500) and a second electrical output of the DC voltage converter is electrically conductively connected to the second output of the charging circuit (200, 300, 400, 500). - at least one first input and one second input for electrical connection to an energy source, - at least one first output and one second output for electrical connection to an electrical component, - at least n first pole connections and n second pole connections, wherein an i-th first pole connection is able to be electrically conductively connected to the first pole of the i-th electrical energy storage unit (R1, R2, R3) and an i-th second pole connection is able to be electrically conductively connected to the second pole of the i-th electrical energy storage unit (R1, R2, R3), - at least n first switches (S11, S12, S13), wherein a first connection of the i-th first switch (S11, S12, S13) is electrically conductively connected to the i-th first pole connection of the i-th electrical energy storage unit (R1, R2, R3), - at least n second switches (S21, S22, S23), wherein a first connection of the i-th second switch (S21, S22, S23) is electrically conductively connected to the i-th second pole connection of the i-th electrical energy storage unit (R1, R2, R3), - at least n-1 third switches (S31, S32), wherein a first connection of the k-th third switch (S31, S32) is electrically conductively connected to the first pole connection of the k-th electrical energy storage unit (R1, R2, R3) and a second connection of the k-th third switch (S31, S32) is electrically conductively connected to the second pole connection of the k+1-th electrical energy storage unit (R1, R2, R3), wherein n > 1 and i ≤ n, k < n are natural numbers, - at least one DC voltage converter,