PARALLEL BATTERY RELAY DIAGNOSIS DEVICE AND METHOD

TA battery relay diagnosis device according to one embodiment of the present invention is a battery relay diagnosis device for diagnosing a battery system comprising a plurality of battery packs connected in parallel, and a charging and discharging control unit for controlling charging and discharging of the plurality of battery backs by being connected between the plurality of battery packs and a load side, wherein a battery pack comprises a battery cell module comprising a plurality of battery cells, and a switching unit comprising a first switch provided between the (+) end of the battery cell module and the load side, and a second switch provided between the (-) end of the battery cell module and the load side, and the battery relay diagnosis device comprises a switching control unit for controlling a current being applied to the battery cell module by on/off controlling the switching unit, and may comprise a diagnosis unit for diagnosing the first switch and the second switch on the basis of an on/off state of the first switch and the second switch.