Furthermore, the X-ray apparatus 100 may further include the third current sensor 750 for measuring a charge current. In other words, the X-ray apparatus 100 may further include the third current sensor 750 at an output terminal of the charger 510. When the lithium ion battery 334 is charged and discharged at the same time, current measured by the first and second current sensors 730 or 740 may be a sum of a discharge current and a charge current. Thus, in order to accurately measure a discharge current and a charge current, the X-ray apparatus 100 may measure the charge current by using the third current sensor 750.

The BMS 332 may turn itself off by using the shutdown circuit 710. When the BMS 332 may check a state of the lithium ion battery 334 to detect hazardous conditions such as over-discharge and overcharge, the BMS 332 may turn itself off by using the shutdown circuit 710 that serves as a protection circuit. When the BMS 332 is turned off, the charge controller and the discharge controller may be turned off to prevent power from being supplied via a charge path and a discharge path. Furthermore, power being supplied to the controller 320 is also cut off, so that the controller 320 may turn off.

The fuse 780 is designed to stop continuous flowing of excessive current that is greater than a nominal value in the power supply 330 and may protect a battery cell when the lithium ion battery 334 is subjected to an external short circuit.

The DC-DC converter 720 may convert a voltage of the lithium ion battery 334 into a DC power for operating the BMS 332.