Please tell me the meaning of this !?

Fire officials discovered that people (renters usually) had removed the batteries from (landlord supplied) fire alarms in order to power their own devices. Since the alarms did not work, there have been injuries and deaths. Therefore, many jurisdictions are now mandating that fire alarms have an enclosed 10 year lithium battery which cannot be removed. At the end of 10 years, the alarm is disposed of and a new one is purchased.

Whatever it is, you have to have the item professionally serviced or an authorized repair person remove and service the battery.