Battery management system, and methods for address allocation and offline reconnection

An address allocation method in a battery management system including a main battery management unit and N sub-battery management units, where N is greater than or equal to 1 and the main battery management unit is connected with the N sub-battery management units through a single bus, comprising:

• powering the battery management system on;
• calculating a local identification code in each of the N sub-battery management units;
• selecting one of the N sub-battery management units through an I/O line using the main battery management unit;
• broadcasting an address allocation message from the main battery management unit, wherein the address allocation message comprises an address number and an identification code;
• receiving the address allocation message at the one of the N sub-battery management units, and when the one of the N sub-battery management units is selected, the one of the N sub-battery management units judges whether the identification code of the address allocation message is identical to the local identification code of the one of the N sub-battery management units:
• when the identification code of the address allocation message is identical to the local identification code of the one of the N sub-battery management units, entering a normal communication state;
• when the identification code of the address allocation message is different from the local identification code of the one of the N sub-battery management units, saving the address number of the address allocation message, and sending the local identification code of the one of the N sub-battery management units to the main battery management unit;
• abandoning the address allocation message when (i) the one of the N sub-battery management units is not selected and there is no connection timeout in the one of the N sub-battery management units, or (ii) the identification code of the address allocation message is not consistent with the local identification code;
• when the connection timeout has not occurred, the one of the N sub battery management units also judges whether the identification code of the address allocation message is consistent with or identical to the local identification code, then:
• when the identification code of the address allocation message is consistent with or identical to the local identification code, entering the normal communication state, and marking a corresponding I/O line fault;
• and
• when the identification code of the address allocation message is not consistent with or identical to the local identification code, sending a first pairing request message from the one of the N sub battery management units to the main battery management unit, wherein the first pairing request message includes the local identification code;
• receiving the first pairing request message and/or the local identification code in the main battery management unit, and searching whether there is a corresponding record in a record sequence;
• when the corresponding record is in the record sequence, sending a second pairing message with a recorded sequence position number as an address;
• and
• when the corresponding record is not in the record sequence, adding or replacing an unused position or location number as the address, and sending a third pairing message with the unused position or location number as the address.