CUTOFF DEVICE

A disconnect device includes a heatsink, a substrate, a first charging relay disposed on a first heat transfer part, a second charging relay disposed on a second heat transfer part, a first discharging relay disposed on a third heat transfer part, a second discharging relay disposed on a fourth heat transfer part, and first and second power storage ends. The first and second discharging relays are disposed closer to the first and second power storage ends than the first and second charging relays are. The first, second, third, and fifth heat transfer parts are aligned in a first direction. The fourth and fifth heat transfer parts are aligned in a second direction perpendicular to the first direction. A heat dissipating performance of the heatsink on the third, fourth, and fifth heat transfer parts is higher than a heat dissipating performance of the heatsink on the first and second heat transfer parts.