A metal halogen electrochemical energy cell system that generates an electrical potential. One embodiment of the system includes at least one cell including at least one positive electrode and at least one negative electrode, at least one electrolyte, a mixing venturi that mixes the electrolyte with a halogen reactant, and a circulation pump that conveys the electrolyte mixed with the halogen reactant through the positive electrode and across the metal electrode. Preferably, the negative electrodes are made of zinc, the metal is zinc, the positive electrodes are made of porous carbonaceous material, the halogen is chlorine, the electrolyte is an aqueous zinc-chloride electrolyte, and the halogen reactant is a chlorine reactant. Also, variations of the system and a method of operation for the systems.