THERMAL MANAGEMENT SYSTEM, SWITCHING VALVE, AND METHOD OF CONTROLLING THERMAL MANAGEMENT SYSTEM

A thermal management circuit has a LT circuit including a reservoir tank and a battery circuit not including the reservoir tank. The thermal management system includes an ECU that controls a five-way valve to switch a plurality of modes with regard to a flow path for a heat medium in the thermal management circuit. The plurality of modes include a first mode (first circuit mode) and a second mode (third circuit mode). The first mode is a mode in which the LT circuit and the battery circuit are connected together in series. The second mode is a mode in which the LT circuit and the battery circuit are connected together in parallel and part of the heat medium flowing in the battery circuit flows to the LT circuit via the five-way valve.