{
  "patent_number": "US 7833668",
  "country": "US",
  "title": "How Fuel Cells Reuse Exhaust Hydrogen for High Efficiency",
  "original_title": "Fuel cell system with greater than 95% fuel utilization",
  "summary": "This patent describes a fuel cell system that captures and recycles over 95% of the unused hydrogen from its exhaust stream using a special pump, significantly boosting efficiency.",
  "what_it_does": "This invention outlines a method for operating a fuel cell system with very high fuel utilization. First, a fuel inlet stream enters a fuel cell stack, which generates electricity and produces a hydrogen-containing fuel exhaust stream (Claim 1). Instead of letting this hydrogen go to waste, a \"cascaded electrochemical hydrogen pump\" then separates at least 95% of the hydrogen from this exhaust (Claim 1). This recovered hydrogen is then fed back into the original fuel inlet stream (Claim 1), effectively reusing it. For example, a solid oxide fuel cell (SOFC) system that normally loses some hydrogen in its exhaust can now capture and re-inject nearly all of it, making the system much more efficient.",
  "what_it_does_not_cover": [
    "Fuel cell systems that do not recirculate hydrogen from their exhaust stream back into the fuel inlet.",
    "Systems that separate less than 95% of the hydrogen contained in the fuel exhaust stream.",
    "Hydrogen separation methods that do not use a \"cascaded electrochemical hydrogen pump.\"",
    "Fuel cell systems that do not include a fuel cell stack (e.g., just a hydrogen pump).",
    "Hydrogen pumps that are not specifically a \"high temperature, low hydration ion exchange membrane cell stack\" if those features are claimed (Claim 4)."
  ],
  "filed": "2007-03-30",
  "granted": "2010-11-16",
  "expires": "2027-03-30",
  "status": "active",
  "holder": "Bloom Energy",
  "holder_url": "https://patentbrief.org/company/bloom-energy",
  "inventors": [
    {
      "name": "James F. McElroy",
      "url": "https://patentbrief.org/inventor/james-f-mcelroy"
    },
    {
      "name": "Arne Watson Ballantine",
      "url": "https://patentbrief.org/inventor/arne-watson-ballantine"
    }
  ],
  "times_cited": 29,
  "tags": [
    "energy",
    "telecommunications",
    "semiconductors",
    "materials"
  ],
  "abstract": "A method of operating a fuel cell system includes providing a fuel inlet stream into a fuel cell stack, operating the fuel cell stack to generate electricity and a hydrogen containing fuel exhaust stream, separating at least a portion of hydrogen contained in the fuel exhaust stream using a cascaded electrochemical hydrogen pump, such as a high temperature, low hydration ion exchange membrane cell stack having at least two membrane cells arranged in process fluid flow series, and providing the hydrogen separated from the fuel exhaust stream into the fuel inlet stream.",
  "url": "https://patentbrief.org/patent/us/7833668/fuel-cell-system-with-greater-than-95-fuel-utilization",
  "markdown_url": "https://patentbrief.org/patent/us/7833668/fuel-cell-system-with-greater-than-95-fuel-utilization/md",
  "google_patents_url": "https://patents.google.com/patent/US7833668",
  "relatedPatents": []
}