A reservoir device includes: a liquid storage structure, configured to store liquid; a liquid feeding assembly, configured to feed the liquid into the liquid storage structure; a barrier assembly; a sensing field generator, configured to generate a sensing field; a sensor; and an electrical control assembly. The barrier assembly is arranged inside the liquid storage structure. The sensor is configured to sense the sensing field. The barrier assembly is configured to float under a buoyance action of the liquid, and to block the sensor from sensing the sensing field when the barrier assembly floats in a first liquid level position. The electrical control assembly is configured to control the liquid feeding assembly to stop feeding the liquid into the liquid storage structure when the barrier assembly blocks the sensor from sensing the sensing field.