Relay control device

A relay control device controls an operation of a relay circuit, the relay circuit including a first main relay, a second main relay, and a pre-charge relay, the relay control device comprising

• a microcomputer that controls on and off states of the first main relay, the second main relay, and the pre-charge relay,
• wherein
• the relay circuit is disposed between a battery and an electric load,
• the battery has a first terminal and a second terminal as a pair of terminals,
• the relay circuit is sealed in a case of a battery pack that includes the battery,
• the first main relay is disposed in a first conduction path which is connected to the first terminal of the battery,
• the second main relay is disposed in a second conduction path which is connected to the second terminal of the battery,
• the pre-charge relay is connected to the second conduction path in parallel with the second main relay,
• the microcomputer switches, at an arbitrary frequency, a first operation sequence and a second operation sequence,
• in the first operation sequence, the microcomputer turns on the pre-charge relay, the first main relay, and the second main relay in order, and then turns off the pre-charge relay, the first main relay, and the second main relay in order, and
• in the second operation sequence, the microcomputer turns on the first main relay, the pre-charge relay, and the second main relay in order, and then turns off the pre-charge relay, the first main relay, and the second main relay in order.