Battery assembly with controllable voltage and method related thereto

A method for maintaining a target voltage of a battery assembly (100) during charging or discharging of the battery assembly (100), wherein the battery assembly (100) is configured to aim at outputting the target voltage, wherein the battery assembly (100) comprises a set of battery modules (110, 160-180), wherein the battery modules (110, 160-180) of the set of battery modules (110, 160-180) are connected in series, wherein the set of battery modules (110, 160-180) comprises a first battery module (110) of a first type and a plurality of second battery modules (160-180) of a second type that is different from the first type, wherein the method comprises:

• sending (A010) a first signal representing a first voltage to be output over the first battery module (110), wherein the first signal is configurable to represent a range of voltages capable of being output over the first battery module (110), wherein the first voltage contributes to the target voltage,
• controlling (A020) each second battery module (160, 170, 180) of the plurality of second battery modules (160-180) by means of a respective second signal, representing a respective configuration for said each second battery module (160, 170, 180), wherein the respective configuration indicates whether said each second battery module (160, 170, 180) is to be switched-on or bypassed with respect to a respective second voltage of said each second battery module (160, 170, 180), wherein the respective second voltage contributes or not contributes to the target voltage depending on the respective configuration,
• determining (A030) the respective configuration for at least one second battery module (160, 170, 180) of the plurality of second battery modules (160-180) based on the target voltage,
• applying (A040) the determined respective configuration to said at least one second battery module (160, 170, 180),
• determining (A050) the first voltage based on a difference between the target voltage and a set of respective second voltages that contributes to the target voltage according to their respective configurations, thereby aiming at that a sum of the first voltage and the set of respective second voltages is equal to the target voltage,
• applying (A060) the first voltage to be represented by the first signal,
• repeatedly performing (A070) a set of actions comprising:
• selecting (A080) a first set of second battery modules (111) and a second set of second battery modules (112, 113) among the plurality of second battery modules (160-180), wherein the respective configuration of each second battery module (160, 170, 180) of the first set is set to switched-on, wherein the respective configuration of each second battery module (160, 170, 180) of the second set is set to bypassed,
• setting (A090) the respective configuration of each second battery module (160, 170, 180) of the first set to bypassed,
• setting (A100) the respective configuration of each second battery module (160, 170, 180) of the second set to switched-on, and
• re-applying (A110) the respective configurations of the first and second sets of second battery modules (160, 170, 180).