A thermal management system, a vehicle, and a thermal management method. The thermal management system includes a tank assembly and a valve unit, the tank assembly includes a shell body and a cover plate, the shell body covers the cover plate and forms an accommodation chamber together with the cover plate, and the valve unit is installed on the shell body; the accommodation chamber is internally provided with a plurality of pipelines for liquid circulation, the shell body has a plurality of connection ports communicating with the accommodation chamber, a first end of the pipeline is correspondingly in communication with the connection port, and a second end of the pipeline and a portion of the pipeline are located outside of the accommodation chamber; and the valve unit has a plurality of valve ports correspondingly in communication with the connection ports.
