Battery management apparatus and method, and battery system including determining whether to replace first and second battery modules

A battery system, comprising:

• a first device and a second device attachable to and detachable from each other,
• wherein the first device is configured to, when a first battery module is connected to the first device:
• measure at least one of voltage, current, and temperature of the first battery module;
• and
• transmit first state information, including at least one of the measured voltage, current, and temperature of the first battery module, to the second device,
• wherein the second device is configured to, when a second battery module is connected to the second device:
• measure at least one of voltage, current, and temperature of the second battery module;
• determine whether it is necessary to replace at least one of the first battery module and the second battery module, based on:
• second state information, including at least one of the measured voltage, current, and temperature of the second battery module, and
• the first state information received from the first device;
• and
• wherein the second device is further configured to:
• estimate at least one of a rest period, an SOC (State Of Charge), and an SOH (State Of Health) of the first battery module, based on the first state information;
• estimate at least one of a rest period, an SOC, and an SOH of the second battery module, based on the second state information;
• perform a first determining operation of determining whether it is necessary to replace at least one of the first battery module and the second battery module, based on a state of the first battery module and a state of the second battery module, the state of the second battery module including whether the second battery module is in a discharge protection state;
• if the second battery module is not in the discharge protection state, perform a second determining operation of determining whether it is necessary to replace at least one of the first battery module and the second battery module, based on the rest period of the first battery module and the rest period of the second battery module;
• if the rest period of the first battery module and the rest period of the second battery module are smaller than a reference rest period, perform a third determining operation of determining whether it is necessary to replace at least one of the first battery module and the second battery module, based on the SOC of the first battery module and the SOC of the second battery module;
• and
• if the SOC of the second battery module is greater than or equal to a reference SOC and less than or equal to the SOC of the first battery module, perform a fourth determining operation of determining whether it is necessary to replace at least one of the first battery module and the second battery module, based on the SOH of the first battery module and the SOH of the second battery module.