A maintenance method is applied to a battery-swappable electric vehicle having an NFC dynamic tag module. The maintenance method includes: retrieving a vehicle identification data of the battery-swappable electric vehicle at a diagnostic system; querying a server for a configuration data associated with the vehicle identification data; writing the vehicle identification data and the configuration data to a new NFC dynamic tag module through NFC; retrieving a new tag identification data from the new NFC dynamic tag module through NFC; writing the new tag identification data to the swappable battery through NFC; providing the new tag identification data to the server, so as to associate the new tag identification data with the vehicle identification data; and replace the NFC dynamic tag module with the new NFC dynamic tag module.