Electric water heater with multiple heat exchange modes

The multi-heat-exchange-mode electric water heater comprises a heat storage area, a backflow area and a heat exchange area, a heat storage module is arranged in the heat storage area, the backflow area is communicated with the heat storage area, and a heating module capable of being controlled to be opened and closed is arranged in the backflow area; the heat exchange area is communicated with the heat storage area and the backflow area, and a heat exchange module is arranged in the heat exchange area. The water heater further comprises a water inlet pipe and a water outlet pipe, the water inlet pipe extends into the heat exchange area, communicates with the heat exchange module and conveys water to be used into the heat exchange module, and the water outlet pipe extends into the heat exchange area, communicates with the heat exchange module and outputs the water to be used in the heat exchange module. The heat exchange medium can circulate in any two of the heat storage area, the backflow area and the heat e