DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Election/Restrictions
Applicant’s election without traverse of group I, claims 1-10, in the reply filed on 9 February 2026 is acknowledged.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-4, 6, and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Hasegawa et al (EP 3604620 A1) in view of Li et al (US 2011/0155583 A1) with evidence from Hatherly (CA 1109019 A).
Hasegawa et al teach (see abstract, fig. 1) an alkaline water electrolysis system comprising:
a rectifier (74) connected to a fluctuating power source (see paragraph [0144], “when electric power supply is stopped during operation under a variable power supply such as renewable energy”) that converts an AC power to a DC power (the inherent function of rectifiers);
a bipolar electrolyzer (50) that generates hydrogen and oxygen through electrolysis of water using an electrolytic solution and a DC voltage supplied from the rectifier; and,
gas-liquid separation tanks (72h and 72o) that are connected to the bipolar electrolyzer and separate the hydrogen and the oxygen from the electrolytic solution and store the electrolytic solution.
Hasegawa et al fail to teach (1) a plurality of the bipolar electrolyzers connected to the single pair of gas-liquid separators and (2) open/close valves provided between the gas-liquid separation tanks and the bipolar electrolyzers.
Regarding (1), Li et al teach (see abstract, fig. 1), in a water electrolysis system powered by a variable power supply of renewable energy, providing multiple bipolar electrolyzers arranged in parallel and selectively operating a number of the electrolyzers depending upon the state of the renewable energy source. All of the bipolar electrolyzers of Li et al are shown as being connected to a single gas-liquid separator for hydrogen and a single gas-liquid separator for oxygen.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of filing to have provided a plurality of bipolar electrolyzers in the system of Hasegawa et al connected in parallel to the single pair of gas-liquid separators as suggested by Li et al for the purpose of increasing hydrogen production capacity while also allowing the system to balance energy consumption to the rate of energy production by the renewable energy.
Regarding (2), it was known and conventional in the field of electrolysis to provide at least one valve in each pipe connected to an electrolyzer to permit isolation of the electrolyzer from the system for periods of maintenance. See Hatherly at fig. 1, page 6, lines 9-12.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of filing to have included valves on each of the liquid lines connecting each bipolar electrolyzer to the remainder of the system, including between each bipolar electrolyzer and the single pair of gas-liquid separators, as claimed to permit maintenance to be performed on one bipolar electrolyzer without having to turn off the entire system.
Regarding claim 2, Hasegawa et al teach (see fig. 1) pressure control valves (80) that adjust the internal pressures of the gas-liquid separators.
Regarding claim 3, Li et al teach (see figs. 2 and 4 and paragraphs [0034] and [0040]-[0042]) providing a control system that controls the operation/stopped status of each individual 0000electrolyzer on the basis of the DC voltage detected by a voltage sensor (416). Therefore, it would have been obvious to one of ordinary skill in the art at the time of filing to have added the control unit of Li et al to the system of Hasegawa et al for the purpose of adjusting the proportion of electrolyzers that were operated at any time to the available DC voltage produced by the renewable energy source.
Regarding claim 4, Li et al teach (see figs. 2 and 5 and paragraphs [0034] and [0040]-[0043]) providing a control system that controls the operation/stopped status of each individual electrolyzer on the basis of the available DC detected by a current sensor (518). Therefore, it would have been obvious to one of ordinary skill in the art at the time of filing to have added the control unit of Li et al to the system of Hasegawa et al for the purpose of adjusting the proportion of electrolyzers that were operated at any time to the available DC current produced by the renewable energy source.
Regarding claim 6, Li et al teach (see figs. 2 and 5 and paragraphs [0034] and [0040]-[0043]) providing a control system that controls the operation/stopped status of each individual electrolyzer on the basis of the available DC detected by a current sensor (518). Therefore, it would have been obvious to one of ordinary skill in the art at the time of filing to have added the control unit of Li et al to the system of Hasegawa et al for the purpose of adjusting the proportion of electrolyzers that were operated at any time to the available DC current produced by the renewable energy source, such that above a certain threshold all electrolyzers were operating but below the threshold only a portion of the electrolyzers were operating.
Regarding claim 9, Hasegawa et al teach (see e.g. paragraph [0144]) supplying the electricity from a renewable energy. Li et al teach (see paragraph [0005]) that renewable energy sources suitable for use to electrolyze water to produce hydrogen gas included wind and solar.
Claims 5 and 7 are rejected under 35 U.S.C. 103 as being unpatentable over Hasegawa et al (EP 3604620 A1) in view of Li et al (US 2011/0155583 A1) as applied to claim 3 above, and further in view of Doland (US 2007/0079611 A1) and Gibson et al (US 2006/0065302 A1).
Li et al teaches controlling the on/off state of the electrolyzers using either voltage or current.
Li et al failed to teach controlling the on/off state of the electrolyzers using current density.
In the same field of endeavor, hydrogen production by electrolysis using renewable sources of electricity, Doland teaches (see abstract, paragraph [0040]) that the renewable power controller could monitor and control parameters including cell current density and sent control signals to the power supply of the electrolyzer cells.
In the same field of endeavor, hydrogen production by electrolysis using renewable sources of electricity, Gibson et al teach (see abstract, paragraph [0044]) that electrolyzers operating at low current density possessed higher efficiency, i.e. cell current density was a known result effective variable.
Therefore, it would have been obvious to one of ordinary skill in the art to have added the functionality of controlling based upon cell current density as suggested by Doland to the control system of Li et al because the cell current density was a recognized result effective variable that effected process efficiency and should therefore be controlled.
Regarding claim 7, as noted by Gibson et al, electrolyzer efficiency increased with lower cell current density. Therefore, it would have been obvious to one of ordinary skill in the art to have increased the total number of active cells (thereby reducing the current density by adding the electrode surface area from another cell) if the current density increased beyond a threshold value that produced unacceptably low efficiency. Likewise, as long as the current density remained low enough, it would have been obvious to one of ordinary skill in the art at the time of filing to have maintained the same number of operating cells in order to maintain the current density.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Hasegawa et al (EP 3604620 A1) in view of Li et al (US 2011/0155583 A1) as applied to claim 3 above, and further in view of Takeuchi et al (US 2019/0024248 A1).
Hasegawa et al and Li et al fail to teach placing a heating device inside the gas-liquid separation tanks.
Takeuchi et al teach (see paragraphs [0003]-[0005]) that when water electrolysis systems were operated in a cold climate or during winter, that it was necessary to add a heater to a gas-liquid separator to maintain the water in a liquid state/warm temperature.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of filing to have added a heating device inside the gas-liquid separators of Hasegawa et al as suggested by Takeuchi et al for the purpose of maintaining the water in a liquid state/warm temperature when the system was used in a cold climate or during winter.
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Hasegawa et al (EP 3604620 A1) in view of Li et al (US 2011/0155583 A1) as applied to claim 3 above, and further in view of Severinsky (US 2006/0211777 A1).
Hasegawa et al and Li et al fail to teach providing a separate rectifier for each bipolar electrolyzer. All of the electrolyzers of Li et al were connected to a single rectifier.
Severinsky teaches (see abstract, paragraphs [0194]-[0195] and fig. 15) that an alternative to providing a single rectifier for a plurality of water electrolysis cells was to provide a plurality of rectifiers, one for each “stack” of electrolysis cells. Selection between a single rectifier or a plurality of rectifiers was done “for convenience of construction, maintenance, and safety”.
Therefore, it would have been obvious to one of ordinary skill in the art at the time of filing to have provided a separate rectifier for each of the bipolar electrolyzers of Li et al as suggested by Severinsky for the purpose of setting the voltage at a level for convenience of construction, maintenance, and safety.
Conclusion
Recognizing that Applicant is located in Japan, the Office has cited a Japanese language equivalent, if available, of the references utilized above.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to HARRY D WILKINS III whose telephone number is (571)272-1251. The examiner can normally be reached M-F 9:30am -6:00pm.
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/HARRY D WILKINS III/Primary Examiner, Art Unit 1794