Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUSRE40060 E1
Publication typeGrant
Application numberUS 11/050,625
Publication dateFeb 12, 2008
Filing dateFeb 4, 2005
Priority dateMar 21, 2000
Fee statusPaid
Also published asDE10013687A1, DE10013687B4, US6596425, US20010033955
Publication number050625, 11050625, US RE40060 E1, US RE40060E1, US-E1-RE40060, USRE40060 E1, USRE40060E1
InventorsDietmar Mirsch, Bernd Scheiterlein
Original AssigneeNucellsys Gmbh
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Fuel cell system
US RE40060 E1
Abstract
A fuel cell system comprises a fuel cell unit and facility for humidifying process gases to provide a fuel for the fuel cell unit, wherein water-carrying media conduits of the fuel cell unit are provided at least in part as heatable media conduits.
Images(2)
Previous page
Next page
Claims(19)
1. A fuel cell system comprising:
a fuel cell unit;
a humidifier unit for humidifying process gases to be fed to the fuel cell unit; and
water-carrying media conduits which provide water to said humidifier unit;
wherein said water carrying media conduits include a heating component arranged to heat at least a portion thereof.
2. The fuel cell system according to claim 1 12, further comprising a unit for extracting water from process gases of said fuel cell unit and providing it to said media carrying conduits at least one media conduit.
3. The fuel cell system according to claim 1 12, wherein said heating component is electrically powered and comprises at least a portion of said at least one media conduits conduit.
4. The fuel cell system according to claim 1 12, wherein the at least one media conduits conduit including said heating component are is provided downstream of the fuel cell unit.
5. The fuel cell system according to claim 1 12, wherein said at least one media conduits conduit including said heating component are is disposed between a water separator for separating water from cathode off-gas of said fuel cell and a metering point for feeding media into a cathode air input.
6. The fuel cell system according to claim 1, further comprising a drain line for discharging water from the fuel cell unit, said drain line including a further heating component.
7. A fuel cell system comprising:
a fuel cell unit;
a first conduit for providing process air to a cathode side input of said fuel cell unit;
a humidifier unit disposed in said first conduit for adding moisture to said process air;
a second conduit for providing water to said humidifier unit;
wherein said second conduit comprises a conduit section having a heating component for warming said water;
the fuel cell system further comprises at least one temperature sensor;
the heating component is activated to heat said second conduit in dependence on a temperature monitored by said temperature sensor; and
the temperature sensor monitors ambient temperature.
8. The fuel cell system according to claim 7, further comprising a unit for extracting water from process gases of said fuel cell unit and providing it to said second conduit.
9. The fuel cell system according to claim 1 12, wherein said heating component comprises a heating sleeve surrounding at least a portion of said media conduits.
10. The fuel cell system according to claim 1 12, wherein said heating component comprises a heating element inside said media conduits.
11. The fuel cell system according to claim 1, further comprising at least one temperature sensor, wherein said heating component is activated to heat said at least a portion of said media conduits in dependence on a temperature monitored by said sensor.
12. The A fuel cell system according to claim 11, wherein comprising:
a fuel cell unit;
a humidifier unit for humidifying process gases to be fed to the fuel cell unit; and
at least one water-carrying media conduit which provides water to said humidifier unit; wherein,
said at least one water carrying media conduit includes a heating component arranged to heat at least a portion thereof;
the fuel cell system further comprises at least one temperature sensor;
the heating component is activated to heat said at least a portion of said at least one media conduit in dependence on a temperature monitored by said sensor; and
saidthe temperature sensor monitors ambient temperature.
13. The fuel cell system according to claim 11, wherein said temperature sensor monitors temperature of a region of said fuel cell system.
14. The fuel cell system according to claim 13, wherein said temperature sensor monitors temperature in proximity to said water carrying media conduits.
15. Temperature regulation apparatus for a fuel cell system having at least one fuel cell unit, said apparatus comprising:
a humidifier unit for humidifying process gases;
heating means for heating water fed to said humidifier, for humidifying said process gases; and
means for supplying heated humidified process gases from said humidifier to said fuel cell unit;
wherein, said heating means heats said water as a function of ambient temperature for said fuel cell system, as determined by a temperature sensor.
16. The apparatus according to claim 15, further comprising a unit for extracting water from exhaust gases from said fuel cell unit and providing it to said media conduit.
17. A method of operating a fuel cell system including at least one fuel cell, said method comprising:
providing a water supply;
humidifying a process gas stream by introducing water from said water supply into said gas stream;
feeding humidified process gas from said gas stream to said fuel cell; and
heating said water from said water supply prior to introduction of said water into said gas stream;
wherein heating of said water in said heating step is performed as a function of ambient temperature for said fuel cell system, as determined by a temperature sensor.
18. The method according to claim 17, wherein said water supply is provided by a water recovery unit which extracts water from exhaust gases from said fuel cell unit.
19. The method according to claim 17, wherein said heating step comprises heating at least a portion of a conduit which supplies water from said water supply to said humidifier.
Description
BACKGROUND AND SUMMARY OF THE INVENTION

This application claims the priority of German patent document 100 13 687.7, filed Mar. 21, 2000, the disclosure of which is expressly incorporated by reference herein.

The invention relates to a fuel cell system having a facility for humidifying process gases to provide fuel for the fuel cell itself.

To prevent the electrode membrane from drying out it is necessary in fuel cells, particularly in those comprising proton-conducting electrolyte membranes (PEM cells), to humidify the process gases such as air or fuel gas. Water produced in the fuel cell, which is customarily extracted from the fuel cell off-gas by means of a water separator, can be used for this purpose, as disclosed, for example in European patent document EP 0 629 014 B1.

Particularly in mobile fuel cell systems comprising proton-conducting electrolyte membranes, high requirements are placed on the control of water balance.

Accordingly, it is an object of the invention to provide a fuel cell system with an improved supply of process water at low temperatures.

This and other objects and advantages are achieved by the fuel cell system according to the invention, in which heatable media conduits are provided downstream of a fuel cell unit, which media conduits are at least partially heatable. This structure has the advantages that process water in the media conduits can be kept liquid independently of ambient conditions, and that the risk of blockages, due to freezing water, of media conduits and/or of valves and pumps disposed in the media conduits is avoided.

Further advantages and refinements of the invention can be gathered from the further claims and the description.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic depiction of a preferred arrangement downstream of a water separator in a fuel cell system according to the invention;

FIG. 2 is a further schematic depiction of a preferred arrangement downstream of a water separator; and

FIG. 3 shows a further preferred arrangement of a fuel cell with water removal.

DETAILED DESCRIPTION OF THE DRAWINGS

The invention is particularly suitable for fuel cell systems in mobile installations. A particular problem with such installations is that when the ambient temperature is below freezing, there is a risk that water present in the system will freeze, and will block conduits and valves and pumps. The installation cannot be started up then, and the components may be damaged by the ice as it forms.

According to the invention, media conduits are provided in the fuel cell system which are heatable. Particularly preferably, media conduits conveying liquid process water are at least partially heatable, at least downstream of a fuel cell.

FIG. 1 depicts a first preferred embodiment of the invention. Disposed in flow path 1 of cathode off-gas of a fuel cell unit (not shown) is a water separator 2, which extracts at least part of the water present in the cathode off-gas. Via a media conduit 3, the process water is passed to a process air humidification system. With the aid of a compressor 7, the process air is delivered, via an air filter 5 and a conduit 6, to the cathode side of a fuel cell unit (not shown). In the conduit 6, the process water from the cathode off-gas is admixed to the process air.

The media conduit 3 is provided with a heatable conduit section 4, or alternatively the entire media conduit 3 can be formed by the heatable conduit section 4, which is preferably electrically heatable. Beneficially, the heatable media conduit or the heatable conduit section 4 is disposed between a water separator 2 for separating water from cathode off-gas and a metering point for feeding media into the cathode air.

Advantageously, the heatable conduit section 4 is supplied with electrical power from a vehicle battery, (e.g., a 12 V battery), or with electrical power from the fuel cell unit. It can also be fitted with a control valve or a pump to adjust the amount of water fed into the process air.

FIG. 2 depicts a further preferred embodiment of the invention, which largely corresponds to that in FIG. 1, with identical elements labeled with identical reference symbols. In the illustrative embodiment shown, humidification in a two-stage compressor is provided. Via an air filter 5, process air passes into a conduit 6 and is compressed in a first compressor 8 and passed on to a second turbo compressor 9. The process water is introduced via the media conduit 3 or the heated conduit section 4 between the two compressors 8, 9 into the conduit 6.

At the metering point at which the process water is introduced into the process air conduit 6, a fine nozzle for introducing the process water is usually provided. The heated conduit section 4 advantageously ensures that no separate heating is required for this nozzle. The use of heated process water prevents water from freezing at the nozzle. This applies equally for any valves and/or pumps for adjusting the amount of the process water which are disposed in the media conduit 3.

FIG. 3 depicts a further preferred arrangement. A fuel cell unit 10 has an end plate 11 on which a first media feeder 12 for the anode and a media offtake 14 for the anode gas, and a second media feeder 13 for the cathode and a second media outlet 15 for the cathode off-gas are provided. (Details of how the media streams are subdivided in the interior of the fuel cell unit 10 are not part of the invention, and are not shown.) Also disposed on the end plate 11 are two water discharge lines 16, 17 which are provided to remove water from the fuel cell unit 10. Beneficially, these water removal lines 16, 17 are likewise provided with heatable conduit sections 18, 19. The water removal lines discharge water which collects in the anode or the cathode of the fuel cell unit 10, preferably into a holding tank of a water separator.

Expediently, all media conduits which may carry liquid water should, if possible, be provided with heatable conduit sections. When running down the fuel cell system it is beneficial to ensure that the water is flushed from the media conduits, so that as little water as possible remains in the system. An advantage of the invention is that even in the event of an emergency shutdown of the fuel cell system, when removal of the water from the system is not possible, the system can be started up again even at low external temperatures at which the water remaining in the system is in the form of ice.

The heatable conduits according to the invention can be made of flexible or rigid material, and can be surrounded by a suitable heating sleeve. Alternatively, they may have a suitable heating element inside the conduit.

Expediently, temperature monitoring of the system is provided in order to ensure that, in the event of the temperature dropping below a critical value (e.g., below the freezing point), the heatable media conduits are heated in the initial stage of starting up the fuel cell system, so that frozen water in the media conduits will be reliably liquefied. One option is to monitor the ambient temperature; alternatively, temperature monitoring in the respective temperature-critical regions of the fuel cell system, especially in or near water-carrying media conduits, can be carried out by one or more temperature sensors.

Another option is to provide for heating the heatable media conduits from time to time in the event of prolonged standstill of the system in a cold environment, if there is the threat of water freezing, in order to maintain the temperature of water-carrying media conduits essentially above the freezing point of water.

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4037024Feb 9, 1973Jul 19, 1977The United States Of America As Represented By The Secretary Of The NavyFuel cell product-water management system
US5271916Jun 30, 1992Dec 21, 1993General Motors CorporationDevice for staged carbon monoxide oxidation
US5360679 *Aug 20, 1993Nov 1, 1994Ballard Power Systems Inc.Hydrocarbon fueled solid polymer fuel cell electric power generation system
US5441821Dec 23, 1994Aug 15, 1995Ballard Power Systems Inc.Electrochemical fuel cell system with a regulated vacuum ejector for recirculation of the fluid fuel stream
US5518705Aug 22, 1994May 21, 1996Ballard Power Systems Inc.Method and apparatus for the two-stage selective oxidation of carbon monoxide in a hydrogen-containing gas mixture
US5753383Dec 2, 1996May 19, 1998Cargnelli; JosephHybrid self-contained heating and electrical power supply process incorporating a hydrogen fuel cell, a thermoelectric generator and a catalytic burner
US5798186Jun 7, 1996Aug 25, 1998Ballard Power Systems Inc.Method and apparatus for commencing operation of a fuel cell electric power generation system below the freezing temperature of water
US5874051Dec 2, 1996Feb 23, 1999Daimler-Benz AgMethod and apparatus for selective catalytic oxidation of carbon monoxide
US5996976Apr 30, 1996Dec 7, 1999Lynntech, Inc.Gas humidification system using water permeable membranes
US6124052Jul 9, 1998Sep 26, 2000Kabushiki Kaisha Toyoda Jidoshokki SeisakushoSolid polymer electrolyte fuel cell system
US6277508Jul 17, 1998Aug 21, 2001International Fuel Cells CorporationFuel cell power supply with exhaust recycling for improved water management
US6383671 *Sep 8, 1999May 7, 2002Lynntech, Inc.Gas humidification device for operation testing and evaluation of fuel cells
US6428915Sep 23, 1999Aug 6, 2002Kabushiki Kaisha Toyoda Jidoshokki SeisakushoApparatus for regulating humidity of process air in fuel cell system
US6440595 *Jun 12, 2000Aug 27, 2002Siemens AgFuel cell system
US6479177Sep 27, 1999Nov 12, 2002Ballard Power Systems Inc.Method for improving the cold starting capability of an electrochemical fuel cell
US6620536Jun 23, 1999Sep 16, 2003Ballard Power Systems AgFuel cell system
US20010021468Mar 7, 2001Sep 13, 2001Honda Giken Kogyo Kabushiki KaishaFuel cell system
DE19832389A1Jul 18, 1998Jan 27, 2000Dbb Fuel Cell Engines GmbhPolymer electrolyte membrane fuel cell system with a fuel gas generator, e.g. a methanol reformer, has a gas-cooled heat exchanger for heat extraction from a reformate gas cleaning stage
EP0629014B1May 17, 1994Apr 16, 1997Daimler-Benz AktiengesellschaftMethod and device for humidyfying reaction gas for operating fuel cell systems
EP0913357A1Oct 27, 1998May 6, 1999Ngk Insulators, Ltd.Reformer and method for operation thereof
EP0941963A1Feb 9, 1999Sep 15, 1999Toyota Jidosha Kabushiki KaishaCarbon monoxide concentration reducing apparatus and method for driving the same
EP0989621A2Mar 3, 1999Mar 29, 2000General Motors CorporationMulti-stage isothermal CO preferential oxidation reactor
EP1061600A2Jun 9, 2000Dec 20, 2000Atecs Mannesmann AGFuel cell arrangement
EP1106571A1Oct 19, 2000Jun 13, 2001XCELLSIS GmbHDevice for selective catalytic oxidation of carbon monoxide
JPH07326376A Title not available
WO1993019005A1Mar 18, 1993Sep 30, 1993Int Fuel Cells CorpMethod of and apparatus for removing carbon monoxide from gaseous media
Classifications
U.S. Classification429/414, 429/434, 429/442
International ClassificationH01M8/04
Cooperative ClassificationY02E60/50, H01M8/04119, H01M8/04156
European ClassificationH01M8/04C2E
Legal Events
DateCodeEventDescription
Jun 2, 2006ASAssignment
Owner name: FUEL CELL SYSTEMS GMBH, GERMANY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:BALLARD POWER SYSTEMS AG;REEL/FRAME:017971/0897
Effective date: 20050729
Owner name: NUCELLSYS GMBH, GERMANY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FUEL CELL SYSTEMS GMBH;REEL/FRAME:017931/0963
Effective date: 20050831
Jan 13, 2011FPAYFee payment
Year of fee payment: 8
Feb 27, 2015REMIMaintenance fee reminder mailed