Method and control device for determining a maximum current limit of a battery system having at least two batteries

An apparatus for controlling a battery system comprising at least two batteries, comprising:

• a control device operatively coupled to the battery system;
• and
• a plurality of control modules, operatively coupled to the control device, wherein the control device and plurality of modules are configured to
• (i) detect a respective individual current for each of the at least two batteries;
• detect a total current of the battery system;
• determine a respective current ratio based on the detected individual currents and the detected total current;
• determine a maximum individual current limits for each of the at least two batteries, proceeding from the respective determined current ratio and a nominal maximum current limit of the respective battery;
• and/or
• (ii) receive or estimate a respective individual resistance of the at least two batteries;
• receive or estimate a total resistance of the battery system;
• determine a respective resistance ratio based on the received or estimated individual resistances and the received or estimated total resistance;
• determine a maximum individual current limits for each of the at least two batteries, proceeding from the respective determined resistance ratio and a nominal maximum current limit of the respective battery;
• select the smallest determined maximum individual current limit as the maximum current limit of the battery system;
• and
• generate a maximum current limit signal based on the determined maximum current limit and utilizing the maximum current limit signal to actively restrict physical current output within the battery system.

A battery system control unit for controlling a battery system comprising at least two batteries, comprising:

• a control device operatively coupled to the battery system;
• and
• a plurality of control modules, operatively coupled to the control device, wherein the control device and plurality of modules are configured to
• (i) detect a respective individual current for each of the at least two batteries;
• detect a total current of the battery system;
• determine a respective current ratio based on the detected individual currents and the detected total current;
• determine a maximum individual current limits for each of the at least two batteries, proceeding from the respective determined current ratio and a nominal maximum current limit of the respective battery;
• and/or
• (ii) receive or estimate a respective individual resistance of the at least two batteries;
• receive or estimate a total resistance of the battery system;
• determine a respective resistance ratio based on the received or estimated individual resistances and the received or estimated total resistance;
• determine a maximum individual current limits for each of the at least two batteries, proceeding from the respective determined resistance ratio and a nominal maximum current limit of the respective battery;
• select the smallest determined maximum individual current limit as the maximum current limit of the battery system;
• and
• generate a maximum current limit signal based on the determined maximum current limit and utilize the maximum current limit signal to actively restrict physical current output within the battery system.