PROTECTION CIRCUIT FOR IN-VEHICLE BATTERY

A protection circuit of an in-vehicle battery has a detection unit that detects at least the temperature of the in-vehicle battery, and a control unit that controls a first relay and a second relay. The control unit performs a first switching control when either the temperature or the output current of the in-vehicle battery detected by the detection unit is in a first abnormality range in a case where the first relay is on and the second relay is off, and performs a second switching control when the temperature of the in-vehicle battery detected by the detection unit is within the first abnormality range or within the second abnormality range after the first switching control.