Definition of Back-up battery:
An on-site or embedded power storage device used to keep critical equipment working during short power outages. This buffer against loss of power prevents inconvenient or dangerous stoppage of critical processes. Once the cycle is finished, the equipment can be safely powered down with minimal danger or damage. Back-up devices are commonly used for computer systems, but manufacturing equipment may also be protected with an emergency power source. In some cases, the back-up battery only supplies enough energy to keep systems running until back-up generators can be brought online.
Meaning of Back-up battery & Back-up battery Definition