Overcurrent protection for battery systems

A battery system, comprising:

• a controller;
• a first battery string including a first battery pack, a first fuse, and a first active overcurrent protection device, wherein the first active overcurrent protection device is configured to disconnect the first battery string from the battery system upon activation by the controller;
• a second battery string including a second battery pack, a second fuse, and a second active overcurrent protection device, wherein the second active overcurrent protection device is configured to disconnect the second battery string from the battery system upon activation by a controller;
• and
• wherein the controller is configured to assign different time delays to the activation of the first and second active overcurrent protection devices, a time delay being representative of an amount of time the controller will delay the activation of an active overcurrent protection device after a value of current in the battery string that the active overcurrent protection device is part of exceeds a threshold value.

A method of operating a battery system, comprising:

• detecting a value of electrical current in each battery string of the battery system, wherein the battery system includes (a) multiples battery strings connected together in parallel, (b) each battery string including one or more battery packs, an active overcurrent protection device, and a passive overcurrent protection device, wherein the active overcurrent protection device is configured to disconnect the battery string from the battery system upon activation by a controller;
• activating using the controller, the active overcurrent protection device of a first battery string of the multiple battery strings a first time after the current in the first battery string exceeds a threshold value;
• and
• activating using the controller, the active overcurrent protection device of a second battery string of the multiple battery strings a second time after the current in the second battery string exceeds the threshold value, wherein the second time is different from the first time.