NOVELTY - The battery has a reaction tube (52) comprising air electrode, outer surface for allowing passage of air through the tube and internal passage, connected with a tank (24) containing an anode paste material. A moving mechanism moves the anode paste material through the internal passage of the reaction tube. A threaded portion comprising polymeric coating is extended from the outer surface of the tube.    USE - Metal-air flow battery such as zinc-air flow battery of battery system used in vehicle such as electric vehicle and hybrid electric vehicle such as hybrid car. Can also be used in aluminum-air flow battery, magnesium-air flow battery, iron-air flow battery and lithium-air flow battery used in dump track, motorcycle, van, semi-trailer truck, golf cart, forklift, backup power application, residential power application, etc.    ADVANTAGE - Desirable flow characteristics and operating characteristics of the zinc-air flow battery can be achieved, by using the composition of the zinc paste and/or the zinc oxide paste. Hence operational lifetime and efficiency of the battery can be improved. Flooding and leakage of paste from the battery can be prevented, since exposure of pastes to the environment. Since reactor of zinc-air flow battery can be coupled to multiple tanks, so that the reactant storage capacity of the battery can be improved. The vaporization rate of water from the electrolyte and rate of carbon dioxide exposure to the air electrode can be increased, so that provision of oxygen and effects of the airflow on the vaporization/carbon dioxide exposure can be balanced desirably. Overheating of battery at high power levels during discharging and charging operations can be prevented, by removing excess heat from the reactor. Mechanical stability and pressure resistance capability of the battery can be improved, due to the layered configuration of the cylindrical reaction tubes. By integrating the current collector for the zinc electrode within the reaction tubes, usage of contact pins in the battery can be prevented and leakage associated with contact pins can be avoided.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of metal-air flow battery.    Zinc air flow battery (10)    Tank (24)    Zinc paste (40)    Zinc oxide paste (42)    Reaction tube (52)