# US 12,111,281 B2 · Hydrogen concentration sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,281 B2 - Document ID: US12111281B2 - Status: Granted - Kind: B2 - Application number: 16/198,044 - Filed: 2018-11-21 - Published: 2020-05-21 - Granted: 2024-10-08 - Earliest claimed: 2018-11-21 - Assignees: Hyaxiom, Inc. - Applicants: Doosan Fuel Cell America, Inc. - Inventors: Joshua Preston; Timothy William Patterson, Jr. - Web page: https://patentgrep.com/patent/US12111281B2 ## CPC - G01N 27/407: for investigating or analysing gases {(G01N27/411 takes precedence)} - G01N 27/417: using cells {, i.e. more than one cell} and probes with solid electrolytes - G01N 27/4074: {for detection of gases other than oxygen} - G01N 33/005: {H2} - G01N 33/0059: {Avoiding interference of a gas with the gas to be measured} - Y02E 60/50: Fuel cells - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract An illustrative example hydrogen concentration sensor includes a hydrogen chamber configured to isolate hydrogen within the hydrogen chamber from gas outside the hydrogen chamber. A hydrogen evolving electrode is configured to generate pure hydrogen within the hydrogen chamber. A reference electrode is situated to be exposed to pure hydrogen within the hydrogen chamber. A detection electrode associated with the reference electrode is situated to be exposed to gas outside the hydrogen chamber. The detection electrode is configured to provide an indication of a concentration of hydrogen in the gas outside the hydrogen chamber. ## Claims ### Claim 1 A fuel cell power plant, comprising: a fuel cell stack; a reformer configured to produce hydrogen fuel for the fuel cell stack; a hydrogen concentration sensor that detects hydrogen concentration in a hydrogen fuel supplied in a supply line to the fuel cell stack; and a controller that is configured to dynamically adjust operation of the reformer such that the reformer produces hydrogen fuel that is supplied in the supply line to the fuel cell stack based, at least in part, on an indication from the hydrogen concentration sensor, the hydrogen concentration sensor comprising: a hydrogen chamber configured to isolate hydrogen within the hydrogen chamber from gas outside the hydrogen chamber; a hydrogen evolving electrode configured to generate pure hydrogen within the hydrogen chamber; a reference electrode situated to be exposed to the pure hydrogen within the hydrogen chamber; and a detection electrode associated with the reference electrode, the detection electrode being situated to be exposed to the gas outside the hydrogen chamber, the detection electrode being configured to provide an indication of a concentration of hydrogen in the gas outside the hydrogen chamber, wherein the hydrogen evolving electrode is part of a first electrochemical cell, the reference electrode and the detection electrode are part of a second electrochemical cell, the first electrochemical cell includes a first matrix containing a liquid electrolyte, the second electrochemical cell includes a second matrix containing a liquid electrolyte, and the first and second electrochemical cells are disposed on a common side of the hydrogen chamber and are separated by a gap established by a wall that protrudes into the hydrogen chamber to establish a constriction between a first region of the hydrogen chamber associated with the hydrogen evolving electrode and a second region of the hydrogen chamber associated with the reference electrode. ### Claim 2 (depends on 1) The fuel cell power plant of claim 1, wherein the hydrogen evolving electrode introduces a positive pressure within the hydrogen chamber. ### Claim 3 (depends on 2) The fuel cell power plant of claim 2, wherein the hydrogen chamber includes a vent; and the positive pressure within the hydrogen chamber prevents the gas outside the hydrogen chamber from entering the hydrogen chamber through the vent. ### Claim 4 (depends on 3) The fuel cell power plant of claim 3, wherein the vent is established along the second region of the hydrogen chamber. ### Claim 5 (depends on 1) The fuel cell power plant of claim 1, wherein the first electrochemical cell comprises a hydrogen oxidizing electrode; the first matrix is at least partially situated between the hydrogen oxidizing electrode and the hydrogen evolving electrode; and a voltage is applied across the hydrogen evolving electrode and the hydrogen oxidizing electrode. ### Claim 6 (depends on 5) The fuel cell power plant of claim 5, wherein the liquid electrolyte in the first matrix comprises phosphoric acid. ### Claim 7 (depends on 5) The fuel cell power plant of claim 5, wherein the second matrix is at least partially situated between the reference electrode and the detection electrode; and a voltage across the reference electrode and the detection electrode provides the indication of the concentration of hydrogen in the gas outside the hydrogen chamber. ### Claim 8 (depends on 7) The fuel cell power plant of claim 7, wherein positive pressure within the hydrogen chamber prevents the gas outside the hydrogen chamber from entering the hydrogen chamber. ### Claim 9 (depends on 7) The fuel cell power plant of claim 7, wherein no current passes at the reference electrode. ### Claim 10 (depends on 1) The fuel cell power plant of claim 1, wherein the second matrix is at least partially situated between the reference electrode and the detection electrode; and a voltage across the reference electrode and the detection electrode provides the indication of the concentration of hydrogen in the gas outside the hydrogen chamber. ### Claim 11 (depends on 10) The fuel cell power plant of claim 10, wherein the liquid electrolyte in the second matrix comprises phosphoric acid. ### Claim 12 (depends on 1) The fuel cell power plant of claim 1, wherein positive pressure within the hydrogen chamber prevents the gas outside the hydrogen chamber from entering the hydrogen chamber. ### Claim 13 (depends on 1) The fuel cell power plant of claim 1, wherein no current passes at the reference electrode.