# US 9,435,040 B2 · Water electrolysis system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,040 B2 - Document ID: US9435040B2 - Status: Granted - Kind: B2 - Application number: 14/410,314 - Filed: 2013-06-25 - Published: 2015-11-26 - Granted: 2016-09-06 - Earliest claimed: 2012-06-25 - Assignees: Nissan Motor Co., Ltd. - Applicants: Nissan Motor Co., Ltd. - Inventors: Takuya Hasegawa; Ryuji Fujieda - Web page: https://patentgrep.com/patent/US9435040B2 ## CPC - C25B 9/17: Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof - C25B 1/04: by electrolysis of water - C25B 9/00: Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features - C25B 15/08: Supplying or removing reactants or electrolytes; Regeneration of electrolytes - C25B 15/081: {Supplying products to non-electrochemical reactors that are combined with the electrochemical cell, e.g. Sabatier reactor} - B01D 53/261: {by adsorption} - B01D 2256/16: Hydrogen - B01D 2259/402: using two beds - Y02E 60/36: Hydrogen production from non-carbon containing sources, e.g. by water electrolysis - C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A water electrolysis system includes a water electrolysis stack that electrolyzes water and generates hydrogen, a dehumidification device that adsorbs and removes moisture contained in the hydrogen generated by the water electrolysis stack, a wet line that supplies the hydrogen generated by the water electrolysis stack to the dehumidification device, a compression device that gradually increases pressure of the hydrogen whose moisture is removed in the dehumidification device, and a purge line that takes out a part of the hydrogen whose pressure is being increased, in the compression device, allows it to pass through the dehumidification device, and allows it to join the wet line. ## Claims ### Claim 1 A water electrolysis system, comprising: a water electrolysis stack configured to electrolyze water and generate hydrogen; a dehumidification device configured to adsorb and remove moisture contained in the hydrogen generated by the water electrolysis stack; a wet line configured to supply the hydrogen generated by the water electrolysis stack to the dehumidification device; a compression device configured to gradually increase pressure of the hydrogen whose moisture is removed in the dehumidification device; and a purge line configured to take out a part of the hydrogen whose pressure is being increased in the compression device, allowing the part of the hydrogen to pass through the dehumidification device, and returning the part of the hydrogen to the wet line, wherein a liquid discharge device is provided on the wet line and is configured to discharge liquid from the wet line, and the purge line allows the part of the hydrogen whose pressure is increased in the compression device to join the wet line between the water electrolysis stack and the liquid discharge device. ### Claim 2 (depends on 1) The water electrolysis system according to claim 1, wherein the pressure of the hydrogen that is taken out of the compression device is higher than pressure of the wet line. ### Claim 3 (depends on 1) The water electrolysis system according to claim 1, wherein the compression device comprises a multiple-stage compressor configured to increase pressure of the hydrogen whose moisture is removed in the dehumidification device, by dividing the hydrogen into at least two, and the purge line allows a part of the hydrogen whose pressure is increased in a first-stage compressor, to join the wet line. ### Claim 4 (depends on 1) The water electrolysis system according to claim 1, wherein the water electrolysis system is mounted on a vehicle that travels by using hydrogen as fuel. ### Claim 5 (depends on 1) The water electrolysis system according to claim 1, further comprising a circulation passage through which a coolant, used for electrolysis in the water electrolysis stack, circulates. ### Claim 6 (depends on 1) The water electrolysis system according to claim 1, wherein the dehumidification device comprises a first absorber and a second absorber, the purge line configured to feed the hydrogen whose pressure is being increased in the compression device to a selected one of the first absorber and the second absorber to renew the absorber, the part of the hydrogen to pass through the dehumidification device returned to the wet line and reintroduced to the dehumidification device.