Patent ID: 8663436

Claim:
A water electrolysis system comprising: a high-pressure water electrolysis apparatus configured to electrolyze water to generate oxygen and hydrogen having a higher pressure than a pressure of the oxygen; and a gas-liquid separation device to separate the hydrogen containing moisture discharged from the high-pressure water electrolysis apparatus into the hydrogen from which the moisture is removed and water, the gas-liquid separation device being to supply the hydrogen from which the moisture has been removed to a hydrogen pipe that communicates with a hydrogen filling unit, the gas-liquid separation device being to discharge the water to a discharge pipe, wherein the gas-liquid separation device includes a block member which includes a gas-liquid separation opening and a water-level detection opening, the gas-liquid separation opening and the water-level detection opening extending substantially vertically and including respective bottom portions which integrally communicate with the discharge pipe, the discharge pipe is disposed at a lower side portion of the block member, the water-level detection opening includes a top portion and a top water-level detection section, the top portion being coupled to an upper portion of the gas-liquid separation opening, the upper portion communicating with the hydrogen pipe disposed at an upper portion of the block member, and the block member further includes an inlet hole in which the hydrogen is introduced from the high-pressure water electrolysis device, the inlet hole being disposed at an upper side portion of the block member, the inlet hole being positioned above the top water-level detection section of the water-level detection opening.