NOVELTY - The battery system has a container (114) storing a concentrated electrolyte, which is in fluid communication with a mixing chamber (112). A pumping system (122) pumps a fluid into the mixing chamber. The mixing chamber mixes fluid and concentrated electrolyte to produce a diluted electrolyte. A thin galvanic cell (110) which is in fluid communication with the mixing chamber, uses the received diluted electrolyte for electrochemical reaction, and removes the used electrolyte solution from the cell.    USE - Zinc-water battery system installed in sea or flowing fresh water environment (claimed) and soil environment.    ADVANTAGE - An environment-friendly battery system which does not require special shipment or disposal protocols, can be provided. Thus, the battery system can be easily deployed in the soil or marine environment. The volume of the battery system can be reduced and the energy storage density of the battery system can be improved. The duration of battery operation can be extended by periodically adding controlled amounts of water to the system.    DETAILED DESCRIPTION - The galvanic cell has cathode material and cathode current collector coated on the inside of a pipe or tube within the cylinder. An anode is located in the center of the pipe or tube. The cathode and the anode are separated by a porous separator. An electrolyte layer is located in the space between the cathode and the anode. The pumping system is provided with a capillary pump which does not consume energy from an external power source. The battery system submerged in the sea or flowing fresh water environment, can use the wave motion, water currents, or water flow for refueling and washing the cell, so that the battery system does not have a requirement to consume energy from an external power source for operation.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of the battery system with water injection device.    Thin galvanic cell (110)    Mixing chamber (112)    Container (114)    Valve for controlling addition of stock solution (118)    Pumping system (122)