Circuit structure

A circuit structure comprising:

• a heat generating component that generates heat when electrical power is supplied;
• a busbar including an electrical connection portion electrically connected to the heat generating component, a heat transfer connection portion provided at a different position from the electrical connection portion, and a detour portion that connects the electrical connection portion and the heat transfer connection portion to each other;
• a base member that has an upper surface on which the heat generating component is arranged and a lower surface, and includes a through hole that passes through the upper surface and the lower surface and accommodates the heat transfer connection portion;
• an insulating plate that is made of an insulating material and is arranged below the heat transfer connection portion;
• and
• a heat dissipation member that is made of a metal and is arranged below the insulating plate,
• wherein the heat generating component is a relay, the relay has a power terminal to which electrical power is supplied, and the electrical connection portion of the busbar is connected to the power terminal,
• a sub busbar different from the busbar is arranged on the insulating plate at a position corresponding to the heat generating component,
• the sub busbar includes a precharge busbar that constitutes a precharge circuit connected in parallel to the relay, and
• in the precharge circuit, a precharge relay and a precharge resistor are connected in series via the precharge busbar.