H01M 8/04223
During start-up or shut-down
Official title: during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
H01M8/04223 (During start-up or shut-down) appears on 2,386 US grants and 3,305 published applications in this corpus.
Search patents in H01M- Granted patents
- 2,386
- Published applications
- 3,305
- Assignees
- 558
- Inventors
- 4,396
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1977 | 2 | 0 |
| 1978 | 0 | 0 |
| 1979 | 0 | 0 |
| 1980 | 1 | 0 |
| 1981 | 2 | 0 |
| 1982 | 0 | 0 |
| 1983 | 3 | 0 |
| 1984 | 0 | 0 |
| 1985 | 1 | 0 |
| 1986 | 0 | 0 |
| 1987 | 9 | 0 |
| 1988 | 3 | 0 |
| 1989 | 1 | 0 |
| 1990 | 4 | 0 |
| 1991 | 6 | 0 |
| 1992 | 5 | 0 |
| 1993 | 4 | 0 |
| 1994 | 4 | 0 |
| 1995 | 9 | 0 |
| 1996 | 6 | 0 |
| 1997 | 7 | 0 |
| 1998 | 7 | 0 |
| 1999 | 10 | 0 |
| 2000 | 16 | 0 |
| 2001 | 22 | 25 |
| 2002 | 28 | 81 |
| 2003 | 50 | 121 |
| 2004 | 63 | 145 |
| 2005 | 63 | 175 |
| 2006 | 62 | 155 |
| 2007 | 54 | 170 |
| 2008 | 73 | 189 |
| 2009 | 83 | 190 |
| 2010 | 118 | 233 |
| 2011 | 149 | 154 |
| 2012 | 149 | 110 |
| 2013 | 124 | 107 |
| 2014 | 138 | 101 |
| 2015 | 111 | 126 |
| 2016 | 107 | 123 |
| 2017 | 97 | 105 |
| 2018 | 97 | 106 |
| 2019 | 101 | 111 |
| 2020 | 103 | 104 |
| 2021 | 95 | 100 |
| 2022 | 119 | 98 |
| 2023 | 110 | 145 |
| 2024 | 46 | 120 |
| 2025 | 78 | 114 |
| 2026 | 46 | 97 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
- H01M 8/04225During start-up897
- H01M 8/04231Purging of the reactants690
- H01M 8/04228During shut-down607
- H01M 8/04268Heating of fuel cells during the start-up of the fuel cells463
- H01M 8/04253Means for solving freezing problems415
- H01M 8/04238Depolarisation127
- H01M 8/04246Short circuiting means for defective fuel cells62
Recent patents
- Method for controlling a drying process of a fuel cell system6 Oct 2026US 12,755,992 B2Robert Bosch GmbH
- Method and system for estimating flight time of a hydrogen fuel cell UAV29 Sep 2026US 12,746,825 B2Industrial Technology Research Institute
- System and method for controlling fuel cell29 Sep 2026US 12,749,692 B2Hyundai Motor Company
- Fuel cell system29 Sep 2026US 12,749,693 B2Toyota Jidosha Kabushiki Kaisha
- Fuel cell system and method for stopping power generation in fuel cell system15 Sep 2026US 12,738,515 B2Honda Motor Co., Ltd.
- Managing a fuel cell system in a fuel cell vehicle8 Oct 2026US 2026/0312087 A1Volvo Truck Corporation
- Device for filtering ambient air8 Oct 2026US 2026/0312089 A1Cellcentric GmbH & Co. KG
- Fuel cell system and purging method for inerting a fuel cell system8 Oct 2026US 2026/0312091 A1
- Method for operating a fuel cell system, and control device8 Oct 2026US 2026/0312093 A1Robert Bosch GmbH
- Diagnosis method for determining a state of a fuel cell system8 Oct 2026US 2026/0312098 A1Robert Bosch GmbH
Most cited
By later US patents
- Method and apparatus for monitoring fuel cell performance359US 5,170,124 AMinister of National Defence of Her Majesty's Canadian Government · 1992
- Purge gas protected transportable pressurized fuel cell modules and their operation in a power plant195US 5,573,867 AWestinghouse Electric Corp. · 1996
- Fuel cell system with combustor-heated reformer172US 6,077,620 AGeneral Motors Corporation · 2000
- High temperature fuel cell power plant165US 7,097,925 B2QuestAir Technologies Inc. · 2006
- Miniature ceramic fuel cell154US 5,641,585 ALockheed Idaho Technologies Company · 1997