CN100573971C - Micro fuel cell structure - Google Patents

Abstract

The assembly that the present invention relates to fuel cell and be used for fuel cell.The heat delivered annex is used to improve the heat management of fuel cell.Each heat delivered annex is set at the outside of bipolar plates, allows to carry out heat delivered between the outside that the inside of bipolar plates and bipolar plates and this annex are close to.This heat delivered annex can be used for heating or the inside of cooled fuel cell heap.Also allow to carry out the new-type channel field design that distributes reacting gas to membrane electrode assembly by the heat management of the improvement that provides of this heat delivered annex of cooling.Mobile buffer can improve the transmission of reacting gas and the removal of product.The bipolar plates of single plate can also comprise the staggered channels designs that reduces single plate thickness.

Description

Micro fuel cell structure

Technical field

The present invention relates to fuel cell technology.Particularly, the present invention relates to be designed for the fuel cell of portable use.

Background technology

Fuel cell makes hydrogen and oxygen electrochemically in conjunction with producing electric energy.Up to the present, the development of fuel cell concentrates on large-scale application, for example is used for the generator of the industrial size of power supply stand-by.

Current lithium ion battery and the similar battery technology of depending on of consumption electronic product and other portable electrical power applications.Yet substituting these conventional batteries technology requirement is increasing.Fuel cell industries is devoted to make enough little fuel cell and is come to be for example kneetop computer power supply of portable consumer electronic device.

The accessory substance that produces the electrochemical reaction of electric energy in the fuel cell comprises steam and carbon dioxide.This electrochemical reaction also produces heat.In the board-like fuel cell that piles up, a plurality of stack of plates and clip a plurality of electrochemical layers together, and wherein the dissipation problem of heat from battery pile remains a challenge.Present thermal management technology depends on and is arranged at adjacent each electrochemical layer and the heat cooling layer between every group of plate.For the fuel cell with 20 plates and nineteen electrochemical layer, traditional thermal technology that removes then needs the nineteen cooling layer.These heat dissipating layers have at interval obviously increased thickness, volume and the size of fuel cell module.

Consider status, need to seek the substitute technology of management heat in fuel cell.In addition, the technology of minimizing size of components also will benefit.

Summary of the invention

The present invention relates to produce the fuel cell of electric energy and be used in assembly in the fuel cell.One aspect of the present invention is the heat management that has improved fuel cell.At this moment, the bipolar plates of fuel cell pack comprises one or more heat delivered annexes.At annex of outer setting of bipolar plates to allow conducting heat between the inside and outside annex at this plate.This annex can carry out the outside thus to the heat of fuel cell pack inside to be regulated.This heat delivered annex can become as a whole with bipolar plate material, to promote to carry out the conduction of heat between the inside of bipolar plates and heat delivered annex.

The heat delivered annex can be used for heating or cooling.During hydrogen consumption and energy produced, for the core of the heat release of cooled fuel cell heap, fuel cell module was the coolant that utilizes the heat delivered annex of flowing through.The heat that allows like this to produce at fuel battery inside a) shifts to the core of the bipolar plates that contacts with membrane electrode assembly from the membrane electrode assembly that produces heat, b) core from bipolar plates shifts to the heat delivered annex through double pole plate base board, and c) shift to the coolant that is used for heating fuel battery waste gas from the heat delivered annex.

Between the initial fuel cell warming up period, for the core of heating fuel battery pile, the catalyst of heat release contacts or is adjacent with the heat delivered annex.Heat medium flow through catalyst and catalyst reaction and produce heat, heat is absorbed by the heat delivered annex.These heats for example conduct to membrane electrode assembly to the inside of fuel cell pack through bipolar plates.In this mode, thermocatalyst and heat delivered annex have reduced and have begun in fuel cell the required warm-up time of generating electricity.

Heat delivered annex described herein does not need traditional to remove thermosphere between bipolar plates.Eliminate traditional thermosphere that removes and reduced the thickness of fuel cell pack, and reduced the size and the volume of fuel cell.

In addition, eliminate traditional removing thermosphere the bipolar plates with flow field is set on the facing surfaces of a veneer between bipolar plates two plates that be used in.Make bipolar plates be changed to the thickness that veneer has obviously reduced fuel cell pack from traditional two plates.Thus, the size of fuel cell and volume also are reduced.

The veneer bipolar plates also can comprise staggered channels designs, and it has reduced the thickness of veneer.Staggered channels designs allows bipolar plates to have two thickness between the apparent surface less than 2x, and wherein x is the degree of depth roughly that is used in the passage in the channel field.The thickness and the size of fuel cell module have so further been reduced.

The heat management mode of the improvement that is provided by cooling heat transmission annex also allows new channel field and gas flow design, and it distributes reacting gas to membrane electrode assembly.For example, provide mobile, collaborative flowing and opposite flow channel field design parallel, that intersect here.

The gas distribution channel field that is used in the bipolar plates also can comprise one or more mobile buffers, and it improves the transmission of reacting gas and the removal of product.The buffer that should flow provides public storage area for gas flow between each passage.If the pressure that some channel jam or run into pressure disturbance or fluctuation on the contrary, buffer reduce in the flow field changes, avoid causing downstream effect by disturbance.The pressure of the gas by reducing to supply to membrane electrode assembly changes, and mobile buffer has improved fuel cell performance.

The innovation that another kind described herein is used for fuel cell relates to the prebuckling end plate, and it is exerted pressure on fuel cell pack more equably.

On the one hand, the present invention relates to be used for the bipolar plates of fuel cell.This bipolar plates comprises substrate, has the first passage field on the first surface of substrate, has the second channel field on the second surface of substrate.The first passage field comprises one group of passage, is used for distributing a kind of gas that is used in fuel cell.The second channel field comprises another group passage, is used for distributing a kind of gas that is used in fuel cell.This bipolar plates also comprise be communicated with substrate heat conduction ground be positioned at the first passage heat delivered annex of portion outside the venue.

On the other hand, the present invention relates to a kind of fuel cell that is used to produce electric energy.This fuel cell comprises fuel cell pack.This fuel cell pack comprises one group of bipolar plates.Each bipolar plates comprises i) be positioned on the bipolar plates first surface and comprise one group of first passage field that is used to distribute the passage of hydrogen, ii) be positioned on the bipolar plates second surface and comprise that one group is used to distribute the second channel field of oxygen and iii) is positioned at first passage portion and the heat delivered annex that is communicated with the substrate heat of bipolar plates conduction ground outside the venue.This fuel cell pack also comprises the membrane electrode assembly between two bipolar plates.This membrane electrode assembly comprises hydrogen catalyst, oxygen catalyst and makes the hydrogen catalyst and the ion-conductive membranes of oxygen catalyst electricity isolation.

Again on the one hand, the present invention relates to be used to produce the fuel cell of electric energy.This fuel cell comprises fuel cell pack.This fuel cell pack comprises one group of bipolar plates.Each bipolar plates comprises i) substrate, on the first surface of substrate, be provided with the first passage field, on the second surface of substrate, be provided with the second channel field.The first passage field comprises the one group of passage that is used to distribute oxygen, and the second channel field comprises the one group of passage that is used to distribute hydrogen.Each bipolar plates also comprise ii) be communicated with the substrate heat conduction ground of bipolar plates and be positioned at the first passage heat delivered annex of portion outside the venue.This fuel cell pack also comprises the membrane electrode assembly between two bipolar plates.This membrane electrode assembly comprises hydrogen catalyst, oxygen catalyst and makes the hydrogen catalyst and the ion-conductive membranes of oxygen catalyst electricity isolation.

On the other hand, the present invention relates to be used to produce the fuel cell of electric energy.This fuel cell comprises fuel cell pack.This fuel cell pack comprises one group of bipolar plates.Each bipolar plates comprises substrate, is provided with the first passage field on the first surface of substrate, is provided with the second channel field on the second surface of substrate.The first passage field comprises the one group of passage that is used to distribute oxygen, and the second channel field comprises the one group of passage that is used to distribute hydrogen.Each bipolar plates also comprise be communicated with the substrate heat of bipolar plates conduction ground and be positioned at the first passage heat delivered annex of portion outside the venue.This fuel cell also comprises and is arranged in the heat delivered annex or the thermocatalyst approaching with it.When running into heat medium, this thermocatalyst produces heat.This fuel cell further comprises hydrogen catalyst, oxygen catalyst and makes the hydrogen catalyst and the ion-conductive membranes of oxygen catalyst electricity isolation.

On the other hand, the present invention relates to be used for the bipolar plates of fuel cell.This bipolar plates comprises the first passage field that is positioned on the bipolar plates first surface and comprises one group of passage.This bipolar plates also comprises the second channel field that is positioned on the bipolar plates second surface and comprises one group of passage.This bipolar plates further comprises the mobile buffer that is used for also this gas being outputed to from the first passage receiver gases of first group of passage first group of second channel the passage.

Again on the one hand, the present invention relates to be used for the fuel cell of transmission electric power.This fuel cell comprises fuel cell pack.This fuel cell pack comprises one group of bipolar plates.Each bipolar plates comprises the first passage field that is positioned on this bipolar plates first surface.This first passage field comprises one group of passage.Each bipolar plates also comprises the second channel field that is positioned on the bipolar plates second surface.This second channel field comprises one group of passage.Each bipolar plates also comprises and is arranged in the mobile buffer that the pressure that is used to reduce first passage field gas flow on the first surface changes.This fuel cell pack also comprises the membrane electrode assembly between two bipolar plates.This membrane electrode assembly comprises hydrogen catalyst, oxygen catalyst and makes the hydrogen catalyst and the ion-conductive membranes of oxygen catalyst electricity isolation.

Again on the other hand, the present invention relates to be used for the bipolar plates of fuel cell.This bipolar plates comprises the substrate with first surface and second surface.This bipolar plates also comprises the first passage field that is positioned on the first surface.This bipolar plates further comprises the second channel field that is positioned on the second surface.Passage in the first passage field has staggered channel depth, and it extends across the channel depth of a passage in the second channel field.

On the other hand, the present invention relates to a kind of fuel cell that is used to produce electric energy.This fuel cell comprises first bipolar plates, and it comprises the first passage field that is positioned on this plate first surface.This fuel cell also comprises membrane electrode assembly, and this membrane electrode assembly comprises hydrogen catalyst, oxygen catalyst and makes the hydrogen catalyst and the ion-conductive membranes of oxygen catalyst electricity isolation.This fuel cell further comprises second bipolar plates, when first bipolar plates and second bipolar plates were assembled on the relative side of membrane electrode assembly, second bipolar plates comprised a relative lip-deep second channel field of the first surface with first bipolar plates that is positioned at this second bipolar plates.This fuel cell also is included in first platform on first bipolar plates, and it has the surface area of first bipolar plates between two passages in the first passage field.This fuel cell also is included in second platform on second bipolar plates, and it has the surface area of second bipolar plates between two passages in the second channel field.When first bipolar plates and second bipolar plates were assembled into opposite flank, membrane electrode assembly ground, first platform was overlapping with second platform at least in part.

On the other hand, the present invention relates to a kind of fuel cell that is used to produce electric energy.This fuel cell comprises one group of bipolar plates.Each bipolar plates comprises first passage field that is positioned on this bipolar plates first surface and the second channel field that is positioned on the bipolar plates second surface.This first passage field comprises one group of passage, and this second channel field comprises one group of passage.This fuel cell pack also comprises the membrane electrode assembly between two bipolar plates.This membrane electrode assembly comprises hydrogen catalyst, oxygen catalyst and makes the hydrogen catalyst and the ion-conductive membranes of oxygen catalyst electricity isolation.This fuel cell further comprises top end plate.This fuel cell also comprises bottom end plate, and it protects top end plate, and when top end plate and bottom end plate are fixed together, exerts pressure to membrane electrode assembly.One of top end plate and bottom end plate are shaped before in being assembled into fuel cell, and it has increased when top end plate and bottom end plate are fixed together, and is applied to membrane electrode assembly central plane pressure partly.

On the other hand, the present invention relates to a kind of bipolar plates that is used for fuel cell.This bipolar plates comprises the substrate with first surface and second surface.This bipolar plates also comprises the first passage field that is positioned on the first surface.This bipolar plates further comprises the second channel field that is positioned on the second surface.This bipolar plates also comprises and is used for transmitting gas or from the manifold of first passage field receiver gases to the first passage field.This bipolar plates also comprises towards the manifold on the second surface, crosses substrate and be used between manifold and first passage field transmitting the manifold passage of gas to second surface from first surface.

On the other hand, the present invention relates to a kind of fuel cell that is used to produce electric energy.This fuel cell comprises first bipolar plates, it comprises: be used for i) that gas is transmitted in first passage field on the first surface of this plate or from the manifold of first passage field receiver gases, the ii) first packing ring platform on first surface, it is the manifold on the first surface in the periphery.This fuel cell also comprises second bipolar plates, and it comprises: the i) manifold that is substantially aligned with the manifold of first plate and ii) at lip-deep second a packing ring platform of second bipolar plates, its in the periphery around second plate manifold.When first plate and second plate were closer to each other, the surface of this second bipolar plates was in the face of the first surface of first bipolar plates.This fuel cell further comprises the membrane electrode assembly between first bipolar plates and second bipolar plates, and this membrane electrode assembly comprises hydrogen catalyst, oxygen catalyst and makes the hydrogen catalyst and the ion-conductive membranes of oxygen catalyst electricity isolation.

On the other hand, the present invention relates to a kind of fuel cell that is used to produce electric energy.This fuel cell comprises fuel cell pack.This fuel cell pack comprises one group of bipolar plates.Each bipolar plates comprises i) be positioned on the first surface of this bipolar plates and have one group of first passage field that is used to distribute the passage of fuel, ii) be positioned on the second surface of this bipolar plates and have the second channel field of one group of passage that is used to distribute oxidant and iii) be arranged on the heat delivered annex that first passage substrate heat conduction portion and bipolar plates ground is communicated with outside the venue.This fuel cell also comprises and is arranged in the heat delivered annex or the thermocatalyst approaching with it.When running into heat medium, this thermocatalyst produces heat.This fuel cell further comprises anode catalyst, cathod catalyst and makes anode catalyst and the ion-conductive membranes of cathod catalyst electricity isolation.

In following description of the present invention and relevant drawings, will be described these and further feature of the present invention and advantage.

Description of drawings

Figure 1A shows a kind of according to an embodiment of the invention fuel cell system that is used to produce electric energy.

Figure 1B shows the schematic operation according to the fuel cell system shown in Figure 1A of a specific embodiment of the present invention.

Fig. 2 A shows and is used for shown in Figure 1A the cross sectional representation of the fuel cell pack of fuel cell according to an embodiment of the invention.

Fig. 2 B shows the exterior top perspective view of fuel cell pack and fuel cell according to another embodiment of the present invention.

Fig. 2 C shows polymer dielectric film fuel cell (PEMFC) structure that is used for the fuel cell according to an embodiment of the invention shown in Figure 1A.

Fig. 2 D shows the top perspective of bipolar plates according to an embodiment of the invention.

Fig. 2 E shows the top orthogonal view of bipolar plates shown in Fig. 2 D.

Fig. 2 F shows the humidifying plate (HP) that is used for fuel cell pack according to an embodiment of the invention.

Fig. 2 G-2L shows the multiple typical channel field structure of the fuel cell that is applicable to Figure 1A.

Fig. 2 M shows the widely used traditional bipolar plates that comprises plate/cooling layer/plate structure.

Fig. 3 A shows the cross sectional representation that comprises the fuel cell pack of a heat delivered annex according to an embodiment of the invention on each bipolar plates.

Fig. 3 B shows the cross sectional representation of heat delivered annex and bipolar plates according to an embodiment of the invention.

Fig. 4 A shows the staggered passage that is arranged on according to an embodiment of the invention on the bipolar plates.

Fig. 4 B shows the bipolar plates on the opposite flank that is arranged on membrane electrode assembly according to an embodiment of the invention.

Fig. 5 A shows the cross sectional representation of the fuel cell pack that is used for the fuel cell shown in Figure 1A according to another embodiment of the present invention.

Fig. 5 B shows the end view that gas stream is crossed the flow path in next door shown in Fig. 5 A.

Fig. 6 shows the end plate that is applicable to the prebuckling that is used for fuel cell shown in Figure 1A according to an embodiment of the invention.

Fig. 7 A shows the top perspective that comprises the bipolar plates of packing ring platform according to one embodiment of the invention.

Fig. 7 B shows the close-up illustration of the platform on the top board shown in Fig. 7 A.

Fig. 7 C shows being staggered of manifold passage on the front cross sectional view of the bipolar plates shown in Fig. 7 A and each plate.

Fig. 7 D shows the sectional view of intercepting by the bipolar plates shown in Fig. 7 A of the manifold passage of top board.

Fig. 7 E shows the sectional view of intercepting by the bipolar plates shown in Fig. 7 A of the manifold passage of base plate.

Embodiment

A plurality of preferred embodiments in conjunction with the accompanying drawings describe the present invention.In the following description, in order to help comprehensive understanding of the present invention a lot of concrete details have been disclosed.Yet,, it is apparent that do not have some or all detail also can implement the present invention to those skilled in the art.In other example,, be not described in detail for known process steps and/or structure for fear of unnecessarily having blured the present invention.

1. fuel cell system

Figure 1A shows a kind of fuel cell system 10 that is used to produce electric energy according to an embodiment of the invention.Fuel cell system 10 comprises hydrogen fuel feedway 12 and fuel cell 20.

Hydrogen supplier 12 provides hydrogen to fuel cell 20.As shown in the figure, feedway 12 comprises hydrogen storage device 14 and/or " reformation " hydrogen supplier.Receive hydrogen though fuel cell 20 is general each from a supply, utilize fuel cell system 10 that a plurality of supplies provide additional hydrogen supply in some applications of great use.Hydrogen storage device 14 output hydrogen, it can be that pure hydrogen source for example is stored in the compression hydrogen in the pressurizing vessel 14.Solid-state hydrogen storage system for example well known to a person skilled in the art that Metal Substrate hydrogen storage device also can be used as hydrogen storage device 14.

" reformation " hydrogen supplier is handled fuels sources so that hydrogen to be provided.Fuels sources 17 can be processed to isolate hydrogen as the carrier of hydrogen.Fuels sources 17 can comprise for example ammonia of any hydrogen-containing fuel stream, hydrocarbon fuel or other hydrogen fuel source.Be suitable for obtainable hydrocarbon fuel sources 17 of the present invention at present and comprise for example methyl alcohol, ethanol, gasoline, propane, butane and natural gas.Multiple hydrocarbon and ammonolysis product also can be made suitable fuels sources 17.Liquid fuel source 17 provides high energy density and has the character that is easy to storage and transport.Storage device 16 can comprise fuel mixture.When fuel processor 15 comprised the steam reforming device, storage device 16 can comprise the fuel mixture of hydrocarbon fuel sources and water.Hydrocarbon fuel source/water fuel mixtures is usually represented by the percent concentration of fuels sources in the water.In one embodiment, the methyl alcohol or the concentration of ethanol scope that comprise in water of fuels sources 17 is 1%-99.9%.Other liquid fuel for example " JP8 " etc. of butane, propane, gasoline, army grade also can be stored in the storage device 16, and the concentration in water is 5-100%.In a specific embodiment, it is 67% methyl alcohol that fuels sources 17 comprises volume content.

As shown in FIG., the reformation hydrogen supplier comprises fuel processor 15 and fuel source storage device 16.Storage device 16 fuel-in-storage sources 17, it can comprise portable and/or disposable fuel element.Disposable fuel element fills for the consumer provides immediately again.In one embodiment, this element is included in the interior telescopic capsule design of plastics tank of hard.Generally flow out from storage device 16 by an independent petrolift control fuels sources 17.If system 10 is connected with load, so fuels sources 17 by control system measure with to processor 15 with the output of the energy level of fuel cell 20 required transmit fuels sources 17 with traffic level.

Fuel processor 15 processing hydrocarbons fuels sources 17 are also exported hydrogen.Traditional hydrogen fuel processor 15 heats under the catalyst existence condition and handles fuels sources 17 to produce hydrogen.Fuel processor 15 comprises reformer, and it is a kind of catalytic unit, and liquid state or gaseous hydrocarbon fuels sources 17 are changed into hydrogen and carbon dioxide.The polytype reformer that is applicable to fuel cell system 10 comprises steam reforming device, autothermal reformer (ATR) or catalyzing part oxidation device (CPOX).The steam reforming device only needs steam to produce hydrogen, and ATR and CPOX reformer are with air and fuel and steam mixing.The fuel that ATR and CPOX system reform is methyl alcohol, diesel oil, regular unleaded and other hydrocarbon for example.In a specific embodiment, storage device 16 provides methyl alcohol 17 to fuel processor 15, and processor allows fuel cell system 10 to be used for the minimized application of temperature at about 250 ℃ or reforming methanol under the low temperature more.The further instruction that is suitable for fuel processor of the present invention is included in title and is Ian Kaye, submits in the patent application of the day total not authorization identical with the present invention for " Annular Fuel Processor and Methods ", invention people.This application at this in the lump as reference.

Fuel cell 20 electrochemically is converted into water with hydrogen and oxygen, produces electrical power and heat in this process.Usually provide oxygen by surrounding air for fuel cell 20.Pure ground or direct oxygen source also can be as the supplies of oxygen.Water normally exists with the form of steam, and this depends on the temperature of fuel cell 20 assemblies.For a lot of fuel cells, this electrochemical reaction also produces carbon dioxide as accessory substance.

In one embodiment, fuel cell 20 is small size polymer dielectric film (PEM) fuel cell, is applicable to portable use, for example consumer electronics device.Polymer dielectric film fuel cell comprises membrane electrode assembly 40, and it is carried out electrochemical reaction and produces electrical power.This membrane electrode assembly comprises hydrogen catalyst, oxygen catalyst and ion-conductive membranes, and it is optionally proton conducting and b a)) hydrogen catalyst and oxygen catalyst electricity are isolated.Hydrogen gas distribution layer comprises this hydrogen catalyst, allows hydrogen to spread therein.Oxygen gas distribution layer comprises this oxygen catalyst, and allows oxygen and hydrogen proton to spread therein.This ion-conductive membranes separates this hydrogen gas distribution layer and oxygen gas distribution layer.From the angle of chemistry, anode comprises this hydrogen gas distribution layer and this hydrogen catalyst, and negative electrode comprises this oxygen gas distribution layer and this oxygen catalyst.

In one embodiment, membrane electrode assembly is between two plates.The channel field of hydrogen distribution 43 on a plate carried out, and the channel field of oxygen distribution 45 on another relative plate carried out.Particularly, hydrogen is distributed to hydrogen gas distribution layer in the first passage field, and oxygen is distributed to oxygen gas distribution layer in the second channel field.The PEM fuel cell generally includes the fuel cell pack with one group of bipolar plates.Term " bipolar " plate is meant the structure of the reaction gas flow paths combination of (being made up of a plate or two plates) on two surfaces that will be clipped between two membrane electrode assembly layers.At this moment, bipolar plates is both as the negative pole end of an adjacent membrane electrode assembly, again as the positive terminal of another adjacent membrane electrode assembly.

From electrical point, anode comprises hydrogen gas distribution layer, hydrogen catalyst and bipolar plates.The act as a fuel negative pole of battery 20 of anode, the electronics that conduction is deviate from from hydrogen molecule, so that it can be used by the outside, for example, for external circuit provides electrical power.In fuel cell pack, bipolar plates is connected in series to be increased in the current potential of every layer of acquisition in the fuel cell pack.From electrical point, negative electrode comprises oxygen gas distribution layer, oxygen catalyst and bipolar plates.Negative electrode is represented the positive pole of fuel cell 20, and electronics is transmitted back to oxygen catalyst from external electronic circuits, and electronics can combine again with hydrogen ion and oxygen and produce water there.

Hydrogen catalyst makes hydrogen be decomposed into proton and electronics.The ion-conductive membranes block electrons is isolated chemical anode (hydrogen gas distribution layer and hydrogen catalyst) and chemical negative electrode (seeing Fig. 2 C) electricity.Ion-conductive membranes also optionally conducts the ion of positive charge.On the electricity, anode is to load (generation electric energy) or battery (storage of electrical energy) conduction electron.Simultaneously, proton passes ion-conductive membranes and moves, and combines with oxygen.Then proton meets at cathode side with the electronics that is utilized, and combines with oxygen to produce water.Oxygen catalyst in the oxygen gas distribution layer promotes this reaction.A kind of oxygen catalyst commonly used comprises the extremely thin platinum powder end that is coated on carbon paper or the carbon cloth.In a lot of designs, use the catalyst of coarse porous to be exposed to the surface area of the platinum in hydrogen and the oxygen with increase.

In one embodiment, fuel cell 20 comprises one group of bipolar plates, and each bipolar plates comprises the channel field of distributing hydrogen and causing on facing surfaces.A kind of channel allocation hydrogen and another kind of channel allocation oxygen on the apparent surface.A plurality of bipolar plates can be stacked to form " fuel cell pack " (Fig. 2 A), and wherein membrane electrode assembly is between each is to adjacent bipolar plates.

Because the process of the generation electrical power in the fuel cell 20 is heat release, fuel cell 20 makes heat dissipate from fuel cell by a heat management system.Fuel cell 20 also can utilize a plurality of humidifying plates (HP) to manage moisture level in the fuel cell.

Though the present invention will be primarily aimed at the PEM fuel cell and discuss, it should be understood that the present invention also can be used for other fuel cell structure.The main distinction between the fuel cell structure is the type of employed ion-conductive membranes.In one embodiment, fuel cell 20 is a phosphoric acid fuel cell, and it uses liquid phosphoric acid to carry out ion-exchange.Solid Oxide Fuel Cell utilizes ceramic compound hard, atresia to carry out ion-exchange, and it is also applicable to the present invention.Usually, the improvement of the one or more bipolar plates that can describe from the present invention of any fuel battery structure and heat management system is benefited.Other such fuel cell structure comprises direct methyl alcohol, alkalescence and molten carbonate fuel cell.

Fuel cell 20 produces direct voltage, and it can be widely used in various uses.For example, the electrical power that produces of fuel cell 20 can be used for providing electrical power for engine or lamp.In one embodiment, the invention provides " small-sized " fuel cell, its design is used for exporting power less than 200 watts (clean or total).The fuel cell of this size typically refers to " micro fuel cell ", is well suited for being used for portable electron device.In one embodiment, fuel cell 20 is used for producing from about 1 milliwatt to about 200 watts.In another embodiment, fuel cell 20 produces from about 3W to about 200W.Fuel cell 20 also can be fuel cell independently, and it is an independent unit that produces power, as long as it has a) oxygen and b) hydrogen or hydrogen heat supply with.Export about 40W and be well suited for being used to the kneetop computer power supply to the fuel cell 20 of about 100W.The surface area that can be increased to a 100-300 battery by the quantity that obviously makes battery and increase plate greater than the power level of 80kW obtains.

Figure 1B shows the schematic operation according to the fuel cell system 10 of a specific embodiment of the present invention.As shown in FIG., fuel cell system 10 comprises fuel container 16, hydrogen fuel source 17, fuel processor 15, fuel cell 20, a plurality of pump 21 and blower fan 35, fuel channel and gas pipeline and one or more valve 23.

Fuel container 16 storage methyl alcohol are as hydrogen fuel source 17.The outlet 26 of fuel container 16 provides methyl alcohol 17 in hydrogen fuel source pipeline 25.As shown in FIG., pipeline 25 is divided into two kinds of pipelines: transmit first pipeline 27 of methyl alcohol 17 and transmit second pipeline 29 of methyl alcohol 17 to the reformer 32 of fuel processor 15 to the burner 30 that is used for fuel processor 15. Pipeline 25,27 and 29 can comprise for example plastic tube.The pump 21a and the 21b that separate are respectively applied for pipeline 27 and 29, make the pipeline pressurization, if necessary, make fuels sources with independently speed transmission.By Instech of Plymouth Meeting, the P625 type pump that PA produces is applicable to that the system 10 into present embodiment transmits liquid methanol.Flow sensor or valve 23 detect and pass on the amount of the methyl alcohol 17 of transmission between storage device 16 and reformer 32 between storage device on the pipeline 29 16 and fuel processor 18.Under the synergy of transducer or valve 23 and suitable control, for example digital control by what apply from the exectorial processor of storing software, pump 21b regulates methyl alcohol 17 from the supply of storage device 16 to reformer 32.

Blower fan 35a transmits oxygen and air via pipeline 31 to the heat exchanger 36 of fuel processor 15 from environment.Blower fan 35b transmits oxygen and air via pipeline 33 to the heat exchanger 36 of fuel processor 15 from environment.In this embodiment, the AD2005DX-K70 type blower fan that is provided by Adda USA of California is suitable for fuel cell system 10 and transmits oxygen and air.Blower fan 37 is blown over fuel cell 20 and its heat delivered annex 46 with cold air.With reference to Fig. 2 D, 2E and 3A the cooling of fuel cell 20 via heat delivered annex 46 described in more detail hereinafter.

Fuel processor 15 receives methyl alcohol 17 from storage device 16, output hydrogen.Fuel processor 15 comprises burner 30, reformer 32, boiling device 34 and heat exchanger 36.Burner 30 comprises from pipeline 27 and receives the inlet of methyl alcohol 17 and the catalyst of generation heat in the presence of methyl alcohol.In one embodiment, burner 30 comprises the outlet to the heated gas of pipeline 42 dischargings, pipeline 41 is sent to fuel cell 20 coming the pre-heating fuel battery through heat delivered annex 46 with heated gas, required warm-up time when quickening initial start fuel cell 20.The outlet of burner 30 is the heated gas of environmental emission towards periphery also.

Boiling device 34 comprises the inlet that receives methyl alcohol 17 from pipeline 29.The structure of boiling device 34 allowed before reformer 32 receives methyl alcohol 17, and the heat that produces in burner 30 heats the methyl alcohol 17 in the boiling device 34.Boiling device 34 comprises the outlet that heated methyl alcohol 17 is provided to reformer 32.

Reformer 32 comprises the inlet that receives heated methyl alcohol 17 from boiling device 34.Catalyst in the reformer 32 and methyl alcohol 17 reactions produce hydrogen and carbon dioxide.The slight heat absorption of this reaction absorbs heat from burner 30.The hydrogen outlet of reformer 32 is to pipeline 39 output hydrogen.In one embodiment, fuel processor 15 also comprises preferential oxidizer, and it intercepts the emission of reformer 32, reduces the content of carbon monoxide in the emission.This preferential oxidizer utilization enters the oxygen of preferential oxidizer and catalyst for example ruthenium or platinum, preferential oxidation carbon monoxide rather than carbon dioxide from air intake.

In one embodiment, fuel processor 15 comprises Dewar type container 150, and it made air preheat before air enters burner 30.Dewar type container 150 has also reduced from the thermal losses of fuel cell 15 by leave the air that heating is introduced before the heat treatment device 15 at air.To a certain extent, Dewar type container 150 is as heat exchanger, utilizes used heat in the fuel processor 15 to improve the heat management and the heat efficiency of fuel processor.Particularly, the used heat of burner 30 can be used for the introducing air that preheating is provided to burner and reduces the heat that is transmitted to the air in the burner, and more heat is sent to reformer 32 thus.

Pipeline 39 transmits hydrogen from fuel processor 15 to fuel cell 20.Gas delivery tube road 31,33 and 39 can comprise for example plastic cement pipe.Hydrogen flow sensor (not shown) also can be added in the amount that detects and pass on the hydrogen that is sent to fuel cell 20 on the pipeline 39.Under the acting in conjunction of hydrogen output transducer and suitable control, for example digital control by what apply from the exectorial processor of storing software, fuel processor 15 is regulated to the hydrogen of fuel cell 20 and is supplied with.

Fuel cell 20 comprises hydrogen arrival end 84 (Fig. 2 B), and it receives hydrogen from pipeline 39, and sends it to hydrogen inlet manifold (Fig. 2 E) so that send it to one or more bipolar plates and their hydrogen distribution passage.Oxygen arrival end 88 (Fig. 2 B) receives oxygen from pipeline 33, and sends it to oxygen inlet manifold (Fig. 2 E) so that send it to one or more bipolar plates and their oxygen distribution passage.Anode off-gas manifold distributes passage to collect waste gas from hydrogen, and sends it to the anode waste gas end, discharges the exhaust in the surrounding environment.The cathode exhaust manifold distributes passage to collect waste gas from oxygen, and sends it to the cathode exhaust end.In one embodiment, cathode exhaust enters pipeline 41, and pipeline 41 comes the pre-heating fuel battery with the heat delivered annex 46 that heated gas transmits through fuel cell 20, required warm-up time when quickening initial start fuel cell 20.

The operation of the fuel cell system 10 shown in Figure 1B is examples, has also considered other variation of fuel cell system design, for example reactant and accessory substance pipeline.In one embodiment, the present invention makes anode waste gas get back to burner 30 from fuel cell 20.Because the hydrogen consumption in the fuel cell 20 often is incomplete, comprise the hydrogen that does not utilize in the waste gas of hydrogen distribution passage, make waste gas circulation get back to burner 30 and make fuel cell system 10 utilize the part that is not used, the efficient of the utilization rate of the hydrogen of raising and system 10.This embodiment further specify and the signal of other fuel cell system 10 has specific descriptions for example in the patent application of the total not authorization that is entitled as " Annular Fuel Processor and Methods " of above-mentioned reference.Except the assembly shown in Figure 1B, system 10 can also comprise other element, for example well known to a person skilled in the art for the favourable electronic controller of the function of system 10, additional pump and valve, additional system sensor, manifold, heat exchanger and electric interconnection device, for the purpose of simplifying, these contents are omitted at this.

2. fuel cell

Fig. 2 A is depicted as the fuel cell pack 60 that is used for fuel cell 20 according to an embodiment of the invention.Fig. 2 B is the exterior top perspective view of fuel cell pack 60 and fuel cell 20 in accordance with another embodiment of the present invention.

At first with reference to Fig. 2 A, fuel cell pack 60 is bipolar sheetpile, and it comprises one group of bipolar plates 44 and one group of membrane electrode assembly (MEA) layer 62.Two membrane electrode assembly layers 62 are adjacent with each bipolar plates 44.Except the membrane electrode assembly 62a top and bottommost and 62b, each membrane electrode assembly 62 is all between two adjacent bipolar plates 44.For membrane electrode assembly 62a and 62b, top end plate and bottom end plate 64a and 64b comprise channel field 72 on the surface adjacent with membrane electrode assembly 62.Bipolar plates 44 is with reference to Fig. 2 B-2I, and 3,4 and 5 make further discussion.Membrane electrode assembly 62 is further described with reference to Fig. 2 C.

With reference to Fig. 2 B, top end plate and bottom end plate 64a and 64b provide mechanical protection for battery pile 60.Each plate 64 also is fixed together bipolar plates 44 and membrane electrode assembly layer 62, and exerts pressure on the area of plane of each bipolar plates 44 and each membrane electrode assembly 62.End plate 64 can comprise the material of suitable rigidity, for example stainless steel, titanium.Aluminium, composition or pottery.In one embodiment, end plate 64 is prebuckling before assembling, and the pressure that has reduced on the area of plane of membrane electrode assembly layer 62 changes.The end plate of prebuckling is done further discussion with reference to Fig. 6.

Bolt 82a is connected with bottom end plate 64a the top with 82b and is fixed together with 64b.As shown in FIG., bolt 82a and 82b enter top end plate 64a, and screw thread enters bottom end plate 64b.Nut can be arranged on the bottom surface of bottom end plate 64b to receive and to fix each bolt.Bolt 82a and 82b can be that commercial obtainable bolt, connecting rod or other are suitable for being connected and the fixed mechanism of fixed top and bottom end plate 64a and 64b.

Get back to Fig. 2 A, bipolar sheetpile 60 comprises 62,11 bipolar plates 44 of 12 membrane electrode assembly layers and 2 end plates 64.Each bipolar plates 44 of piling up in 60 also comprises two heat delivered annexes 46.More specifically, each bipolar plates 44 be included in plate a side heat delivered annex 46a and at the heat delivered annex 46b of opposite side.Heat delivered annex 46 is explained in detail with reference to Fig. 2 E, 3A and 3B.

The quantity of bipolar plates 44 and membrane electrode assembly layer 62 can change along with the design of fuel cell pack 60 in every group.In fuel cell pack 60, pile up parallel layer and allow effectively to utilize as seen, increase the energy density of fuel cell 20.In one embodiment, each membrane electrode assembly 62 produces 0.7V, and the quantity of membrane electrode assembly layer 62 and bipolar plates 44 is selected according to required voltage.Another kind of optional mode is that the quantity of membrane electrode assembly layer 62 and bipolar plates 44 can be selected according to the thickness that allows in electronic installation.Utilize one or more following space saving techniques, fuel cell 20 can comprise above 10 membrane electrode assembly layers, and the thickness of whole assembly is less than 1 centimetre.The fuel cell pack 60 that has from 1 membrane electrode assembly 62 to a hundreds of membrane electrode assembly 62 is applicable to a variety of application.The battery pile 60 that has from about 3 membrane electrode assemblies 62 to about 20 membrane electrode assemblies 62 also is applicable to multiple use.The size of fuel cell 20 and design also can be designed and be used to export given power.

With reference to Fig. 2 B, fuel cell 20 comprises two anode taps opening to the outside of fuel cell pack 60: inlet anode tap or inlet hydrogen end 84 and one outlet anode tap or outlet hydrogen end 86.Inlet hydrogen end 84 is positioned on the top end plate 64a, receives hydrogen with the inlet duct coupling, and opens to inlet hydrogen gas manifold 102 (seeing Fig. 2 E and 2F), and its channel field 72 that is used on battery pile 60 each bipolar plates 44 transmits inlet hydrogen.The port of export 86 receives emission gases from anode off-gas manifold 104 (seeing Fig. 2 E and 2F), and it is used for collecting waste gas from the anode passages field 72 of each bipolar plates 44.The port of export 86 can be directly environmental emission waste gas or by the pipeline that is connected with the port of export 86 environmental emission waste gas towards periphery towards periphery.

Fuel cell 20 comprises two cathode portion: inlet cathode terminal or inlet oxygen end 88 and export cathode terminal or go out saliva/steam end 90.Inlet oxygen end 88 is positioned at bottom end plate 64b and goes up (seeing Fig. 2 F), with inlet duct coupling reception environment air, and open to inlet oxygen manifold 106, and its channel field 72 that is used on battery pile 60 each bipolar plates 44 transmits enter the mouth oxygen and air.Go out saliva/steam end 90 from cathode exhaust manifold 108 (seeing Fig. 2 E and 2F) receiver gases, it is used for collecting water (being generally steam) from the cathode channel field 72 of each bipolar plates 44.

Fig. 2 C is depicted as polymer dielectric film fuel cell (PEMFC) structure 120 that is used in according to an embodiment of the invention in the fuel cell 20.As shown in FIG., PEMFC structure 120 comprises two bipolar plates 44 and the membrane electrode assembly layer (perhaps MEA) 62 that is clipped in two bipolar plates, 44 centres.Membrane electrode assembly 62 is a water with hydrogen and oxygen electrochemical conversion, produces electrical power and heat in this process.Membrane electrode assembly 62 comprises anode gas diffusion layer 122, cathode gas diffusion layer 124, hydrogen catalyst 126, ion-conductive membranes 128, anode electrode 130, cathode electrode 132 and oxygen catalyst 134.

Hydrogen gas (the H of pressurization ₂), for example provide by hydrogen-containing gas stream (or " reformate "), enter fuel cell 20 via hydrogen port 84, then through inlet hydrogen gas manifold 102 be positioned at the hydrogen channel 74 of the hydrogen channel field 72a on the anode surface of bipolar plates 44a.Hydrogen channel 74 is to opening at the anode surface 75 of bipolar plates 44a and the anode gas diffusion layer 122 between the ion-conductive membranes 128.Pressure impels hydrogen to enter the anode gas diffusion layer 122 of hydrogen permeable, and crosses the hydrogen catalyst 126 that is arranged on the anode gas diffusion layer 122.Work as H ₂When molecule contacted with hydrogen catalyst 126, it was decomposed into two H ⁺Ion (proton) and two electronics (e).The oxygen that proton passes in ion-conductive membranes 128 and the cathode gas diffusion layer 124 combines.Electronics passes anode electrode 130, and they produce the voltage (for example power supply of kneetop computer) that is used for external circuit at this.After outside the use, electronics flows to the cathode electrode 132 of PEMFC structure 120.

Hydrogen catalyst 126 is decomposed into proton and electronics with hydrogen.Appropriate catalyst 126 comprises the platinum on for example platinum, ruthenium and platinum black or platinum carbon and/or the carbon nano-tube.Anode gas diffusion layer 122 comprises any permission hydrogen diffusion and can support hydrogen catalyst 126 so that the material that this catalyst and hydrogen molecule react.A kind of so suitable layer comprises the carbon paper of woven or nonwoven.Other suitable gas diffusion layers 122 materials can comprise carborundum substrate and mixture woven or nonwoven carbon paper and Teflon.

At the cathode side of PEMFC structure 120, pressurization be loaded with oxygen (O ₂) air enter fuel cell 20 via oxygen port 88, then through inlet oxygen manifold 106, and through being positioned at the oxygen passage 76 of the oxygen channel field 72b on the cathode surface 77 of bipolar plates 44b.Oxygen passage 76 is to opening at the cathode surface 77 of bipolar plates 44b and the cathode gas diffusion layer 124 between the ion-conductive membranes 128.Pressure impels oxygen to enter cathode gas diffusion layer 124, and crosses the oxygen catalyst 134 that is arranged on the cathode gas diffusion layer 124.Work as O ₂When molecule contacted with oxygen catalyst 134, it was decomposed into two oxygen atoms.Two H of the ion-conductive membranes 128 of ion selectivity have been passed ⁺Ion and an oxygen atom combine with two electronics that return from external circuit and generate hydrone (H ₂O).Cathode channel 76 discharge waters, water normally exists with the form of steam.In an independent membrane electrode assembly layer 62, should react the voltage that produces about 0.7V.

Cathode gas diffusion layer 124 comprises permission oxygen and hydrogen diffusion of protons, also can support oxygen catalyst 134 so that the material that this catalyst 134 and oxygen and hydrogen react.Suitable gas diffusion layers 124 can comprise for example carbon paper or carbon cloth.Other suitable gas diffusion layers 124 materials can comprise carborundum substrate and mixture woven or nonwoven carbon paper and Teflon.Oxygen catalyst 134 promotes oxygen and hydrogen to generate the reaction of water.A kind of catalyst commonly used 134 comprises platinum.The coarse porous catalyst 134 of use increases the surface area to the catalyst 134 of hydrogen or oxygen exposure in a lot of designs.For example, platinum can extremely thin being coated on carbon paper or the carbon cloth cathode diffusion layer 124 of pulverulence.

Ion-conductive membranes 128 passes film 128 by block electrons isolates anode and cathodic electricity.Thus, film 128 prevents that electronics from passing through between gas diffusion layers 122 and gas diffusion layers 124.Ion-conductive membranes 128 is also optionally from the ion of gas diffusion layers 122 to gas diffusion layers 124 conduction positive charges, for example hydrogen proton.For fuel cell 20, proton moves through film 128, and electronics is sent to electronic load or battery.In one embodiment, ion-conductive membranes 128 comprises electrolyte.A kind ofly be applicable to that the electrolyte of fuel cell 20 is PEMEAS USA AG ofMurray Hill, the Celtec 1000 of NJ (www.pemeas.com).Comprise that this electrolytical fuel cell 20 has better carbon monoxide tolerance usually, can not need humidifying.Ion-conductive membranes 128 can also use phosphoric acid matrix, and it comprises the porous barrier that is full of phosphoric acid.The alternative ion-conductive membranes 128 that is applicable to fuel cell 20 can be widely from for example Unitedtechnologies, DuPont, and 3M company and other manufacturer well known in the art obtain there.For example, WL Gore Associates of Elkton, MD makes primea Series 58, and it is for being applicable to cryogenic film electrode assemblie of the present invention.

Anode 130 is meant than negative pole electronegative potential or membrane electrode assembly layer 62, and the electronics from hydrogen molecule, deviate from of conduction so that its can be utilized by the outside.Anode 130 comprises the electron conduction character of anode gas diffusion layer 122, catalyst 126 and bipolar plates 44.Thus, bipolar plates 44 is formed on plate and b its inside, that be used for distributing in the active region that comprises catalyst 126 passage 76 of hydrogen as a) having) the electron conduction element of fuel cell 20 anodes 130.For fuel cell pack 60, bipolar plates 44 is connected in series to increase the voltage that each membrane electrode assembly 62 produces.130 on the anode of the accumulation of fuel cell 20 comprises each bipolar plates 44 of series connection, and to outside electronic load (utilizing electric energy) or battery (storage of electrical energy) conduction electron.

Negative electrode 132 is represented the positive electrode of fuel cell 20, and to catalyst 134 conduction electrons, can combine generation water again with hydrogen ion and oxygen at this electronics.Negative electrode 132 comprises the electron conduction character of cathode gas diffusion layer 124, catalyst 134 and bipolar plates 44.Thus, bipolar plates 44 is formed on plate and b its inside, that be used for distributing in the active region that comprises catalyst 134 passage 76 of oxygen and air as a) having) the electron conduction element of fuel cell 20 negative electrodes 132.The negative electrode 132 of the accumulation of fuel cell 20 comprises each bipolar plates 44 of series connection, and electronics is conducted from external electronic circuits.

In one embodiment, fuel cell 20 does not need outside humidification machine or heat exchanger, and 60 needs hydrogen of battery pile and air produce electrical power.Another kind of optional mode is that fuel cell 20 can utilize the humidifying of fuel cell 20 negative electrodes to improve performance.For some fuel cell pack 60 designs, the negative electrode humidifying has improved the power and the operation lifetime of fuel cell.Fig. 2 F is depicted as the humidifying plate 160 that uses according to an embodiment of the invention in fuel cell pack 60.

Humidifying plate 160 comprises the structure on basic plane, is made of two facing surfaces 162, and each surface comprises that humidifying flow field 164 is arranged on each surface 162 and (only shows upper surface and humidifying flow field 164).Water-permeable membrane 168 (for example Nafion) is arranged between each humidifying plate 160.Cathode exhaust (from the bipolar plates 44 of membrane electrode assembly layer 62) is supplied with through a humidifying flow field 164 of humidifying plate 160, and cathode inlet gas (going to the bipolar plates of membrane electrode assembly layer 62) is supplied with through other humidifying flow field 164.Film 168 allows steam from one another strand of air-flow process, and does not allow different air-flows to mix.The steam of cathode exhaust and heat supply to cathode inlet air flow through water-permeable membrane 168 thus, thus humidifying and heated cathode inlet air flow.Humidifying flow field 164 can be used for allowing cathode inlet and exit flow convection current, works in coordination with and flow or cross flow one.

In one embodiment, fuel cell pack 60 comprises a plurality of humidifying plates, accounts for the 25-70% of the sum of bipolar plates 44 greatly.Humidifying plate 160 can be plastic plate for example molded or machine-building.Humidifying plate 160 does not need thermal conductivity or conductivity.

Though the invention provides the bipolar plates 44 that has the channel field 72 of distributing hydrogen and oxygen on the opposite flank of single plate 44, a lot of embodiment described herein are suitable for using traditional bipolar plate assembly, it utilizes two independent plates to distribute hydrogen and oxygen.Fig. 2 M is depicted as widely used traditional bipolar plates 300, and it comprises plate/cooling layer/plate structure.

Bipolar plates 300 comprises two plate 302a and 302b, accompanies cooling layer 304 between the two.Top board 302a comprises the channel field 306a that distributes oxygen on its upper surface 308.Base plate 302b comprises the channel field 306b that distributes hydrogen (perhaps oxygen, when top board 302a distributes hydrogen) on its cell membrane 308.Has for example deionized water cooling duct 310 of flowing through of coolant in the cooling layer 304.Coolant cools off each plate 302.The flowing of coolant can make that temperature raises on the direction identical with the direction that reduces of oxygen partial pressure in the negative electrode.Similar to bipolar plates 44, bipolar plates 300 also is " bipolar plates ", because it is as the negative electrode of a membrane electrode assembly and the anode of another membrane electrode assembly.The effect of 300 pairs of fuel cells of bipolar plates is similar for the effect of fuel cell to above-mentioned bipolar plates 44.Top board and base plate 302a and 302b can comprise silicon, etch passage so that channel field 306 to be provided on their surface.

Though in fuel cell 20, use bipolar plates 300 to cause the thickness of fuel cell greater than using bipolar plates 44, the suitable bipolar plates 300 of using of a lot of embodiment of the present invention.For example, the mobile buffer of describing with reference to Fig. 2 E is well suited for using bipolar plates 300.In addition, comprise that in battery pile the fuel cell of bipolar plates 300 will benefit from the end plate 64 of prebuckling as shown in Figure 6.Bipolar plates 300 also can be utilized staggered passage, heating annex and/or flow field described here.

In one embodiment, fuel cell 20 comprises the bipolar plates 44 that is arranged in the battery pile, and each plate 44 has different manifolds and arranges.Fig. 2 F is depicted as the design of fuel cell pack 60 in accordance with another embodiment of the present invention, and wherein bipolar plates comprises that different air inlets and waste gas distribute.

For the fuel cell pack among Fig. 2 F 60, cathode flame 170 is discharged the air-flow counter-current flow from base plate 64b (may supply with recently with air) two the humidifying plates 164 that enter and flow through with negative electrode here, obtains humidifying and heat thus.Flow through three membrane electrode assemblies 62 of cathode flame 170 arrive cathode exhaust manifolds 108 then, and it turns back to humidifying plate 160 with air-flow 170, flows through the cathode flame 170 of introducing this its.Cathode flame 170 is then from the port of export 90 dischargings.

Anode gas flow 172 enters arrival end 84, flows through next bipolar plates by a top bipolar plates 44 continuously, with cathode flame 170 counter-current flow.Air-flow 172 at first enters last bipolar plates 44 that cathode flame 170 flows through.The mobile minimizing with fuel and oxidant of anode gas flow 172 and cathode flame 170 mutual adverse currents causes concentration to reduce the relevant battery pressure loss owing to being consumed by each membrane electrode assembly layer 62.

These fuel cell pack 60 flow paths allow reformate and cathode exhaust gas air-flow to arrive and flow out the short pipeline path of fuel processor.In order to improve pipeline, the structure of bipolar plates 44 has been illustrated in fuel cell pack 60 designs shown in Fig. 2 J, and each all is designed into the position of concrete plate 44 in fuel cell pack 60.More specifically, bipolar plates 44m, 44n can comprise different air inlets and exhaust manifold design with 44o.For example, bipolar plates 44o comprises an outer cathode manifold 107, and bipolar plates 44m does not have.For example the MEMs manufacturing technology has been considered the manifold design of the such variation that combines with bipolar plates 44.It is to be the flow patterns of bipolar fuel cell heap 60 exploitation complexity with minimum fringe cost that the manifold design that changes can make the designer.

Though the present invention so far is primarily aimed at reformate methanol fuel cells (RMFC) and discusses, but the present invention also can be applied to the fuel cell of other type, for example Solid Oxide Fuel Cell (SOFC), phosphoric acid fuel cell (PAFC), direct methanol fuel cell (DMFC) or direct alcohol fuel cell (DEFC).At this moment, fuel cell 20 comprises the peculiar structure of these structures, as what it will be appreciated by those skilled in the art that.DMFC or DEFC receive and handle fuel.More specifically, DMFC or DEFC receive liquid methanol or ethanol respectively, and fuel is sent into fuel cell pack 60, and the hydrogen that liquid fuel is treated as separation is used to produce electrical power.For DMFC, channel field 72 dispense liquid methyl alcohol rather than the hydrogen in the bipolar plates 44.126 of above-mentioned hydrogen catalysts comprise suitable being used for from the anode catalyst of methyl alcohol separation of hydrogen.Oxygen catalyst 128 can comprise suitable being used to and handle for example catalyst of peroxide of oxygen or other the suitable oxidant that is used for DMFC.General, hydrogen catalyst 126 also is meant the anode catalyst in other fuel cell structure usually, and can comprise any appropriate catalyst that is used for producing at fuel cell the hydrogen of electrical power of for example directly removing from DMFC fuel.Oxidant can comprise anyly can be not limited to above-mentioned oxygen with the liquid or the gas of oxidized.Also can from the present invention described here, be benefited such as SOFC, PAFC or MCFC.At this moment, fuel cell 20 comprises the anode fuel and the oxidant of anode catalyst 126, cathod catalyst 128, the SOFC according to concrete, PAFC or MCFC design.

3. bipolar plates

Fig. 2 D shows the top perspective of bipolar plates 44 according to an embodiment of the invention.Fig. 2 E shows the top orthogonal view of bipolar plates 44.Bipolar plates 44 is independent plates 44, and it has respectively at the facing surfaces 75a of independent plate 44 and first passage field 72a on the 75b and second channel field 72b.

On function, bipolar plates a) to gas distribution layer 122 and 124 and their catalyst separately transmit and distribute reacting gas, b) in battery pile 60, between membrane electrode assembly layer 62, keep reacting gas to be isolated from each other, c) from membrane electrode assembly layer 62 discharging electrochemical reaction accessory substance, d) promote to and/or from the heat conduction of membrane electrode assembly layer 62 and fuel cell pack 60, e) transmit electronics from anode to negative electrode as electronic conductor, and f) comprises gas air inlet and gas exhaust manifold, be used for transmitting gas to other bipolar plates 44 of fuel cell pack 60.

On the structure, bipolar plates 44 has flat relatively section, and comprises relative upper surface and lower surface 75a and 75b (have only upper surface 75a in Fig. 2 D and 2E, 75b sees Fig. 2 C) and a plurality of side 78.Surface 75 is the plane substantially, except passage 76 is as the groove that is formed in the substrate 89.Side 78 comprises the adjacent part in edge of the bipolar plates 44 between bipolar plates 44 and two surfaces 75.Shown in Fig. 2 E, bipolar plates 44 is general quadrangle, and inlet manifold, exhaust manifold and heat delivered annex 46 make it depart from quadrangle.Be applicable to a variety of application from about 0.125 millimeter to about 1 millimeter bipolar plates 44 at the thickness of surface between 75.But the bipolar plates of other application used thickness between about 0.25 millimeter to about 0.75 millimeter.In a specific embodiment, plate 44 all has on any point of the section of plate 44 and is not more than about 2 millimeters thickness.In another embodiment, plate 44 has the thickness of 1mm initial before any machining.At this moment, obtain the fuel cell 20 of whole component thickness less than 1cm.

Manifold on each plate 44 is used for that a lip-deep channel field to plate 44 transmits gas or from channel field 72 receiver gasess.The manifold of bipolar plates 44 is included in hole or the hole in the substrate 89, when in battery pile 60 during with other plate 44 combinations, constitutes gas communication manifolds in the plate 44 (for example 102,104,106 and 108).Thus, when plate 44 is stacked, their manifold substantially point-blank, these manifolds allow gases to be sent to each plate 44 or flow out from each plate 44.

Bipolar plates 44 is included in lip-deep channel field 72 or " flow field " of each plate 44.Each channel field 72 comprises the one or more passages 76 in the substrate 89 that is formed on plate 44, so that these passages are present under the surface of plate 44.Each channel field 72 is that one or more reacting gass are distributed in the active region 85 of fuel cell pack 60.Bipolar plates 44 comprises the first passage field 72a on the anode surface 75a of bipolar plates 44, and its anode is distributed hydrogen (Fig. 2 C), and the second channel field 72b on relative cathode surface 75b distributes oxygen to negative electrode.Particularly, channel field 72a comprises a plurality of passages 76, and it allows oxygen and air flow anodic gas dispersion layer 122, and channel field 72b comprises that a plurality of its allows oxygen and air flow cathode gas dispersion layer 124.For fuel cell pack 60, each channel field 72 is used for receiving reacting gas from inlet manifold 102 or 106, and is used for distributing these reacting gass to gas diffusion layers 122 or 124.Each channel field 72 is also collected byproduct of reaction and is used for emitting from fuel cell 20.Line up to look into preceding when bipolar plates 44 and be stacked on a time-out in 60, adjacent plate 44 sandwich membrane electrode assembly layers 62 are so that the anode surface 75a of a bipolar plates 44 cathode surface 75b with adjacent bipolar plates 44 on the opposite flank of this membrane electrode assembly layer 62 is adjacent.

Each channel field 72 comprises one group of passage that is used for distributing to the active region of bipolar plates oxygen.The number of passage 76 and structure can change with design in each channel field 72.Fig. 2 G-2L shows multiple channel field 72 structures that are applicable to as fuel cell 20.

The active region 85 of fuel cell 20 is meant the part that electrochemical reaction produces electric energy takes place in the fuel cell pack 60.Typically, active region 85 needs the function of membrane electrode assembly layer 62 (and its part for example gas distribution layer 122 and 124, relevant catalyst and ion-conductive membranes 128) and is carried out the distribution of gas by channel field.Thus, the zone of the membrane electrode assembly layer 62 that is limited by channel field 72 can constitute active region 85.Opposite, the part except distribution and planar section of channel field 72 is not included in the active region 85, and the part except surface portion of membrane electrode assembly layer 62 also is not included in the active region.According to structure, single membrane electrode assembly layer 62 can comprise a plurality of active regions 85.A plurality of active regions 85 need not to be continuous, and single membrane electrode assembly layer does not need to be constrained to and has only single continuous active region 85.

Channel field 72 is positioned at the core of plate 44.The hermetic unit 87 of plate 44 surrounds channel field 72 near the periphery of each plate 44.Sealing part 87 surrounds channel field 72 and surrounds near plate 44 peripheral manifold 102-108.Hermetic unit 87 is with membrane electrode assembly layer 62 and manifold 102-108 sealing.Packing ring can be set between the hermetic unit 87 of adjacent plate 44 to promote sealing closely.Exert pressure from the packing ring of pressure between every pair of adjacent panels 44 of bolt 82 and end plate 64 then.The packing ring of the screen printing of being made by silicone is applicable to a lot of fuel cell packs 60.In another embodiment, with respect to the substrate 89 of plate 44 cores, be enhanced at the substrate 89 of hermetic unit 87.At this moment, membrane electrode assembly layer 62 is present in lower recess, and when being exerted pressure by bolt 82 and end plate 64, the substrate 89 that is enhanced in the hermetic unit 87 of adjacent panels 44 is as potted component.

Channel field 72 can influence the performance of fuel cell 20.More specifically, the design of channel field 72 can change the plane continuity that gas distributes between the bipolar plates 44, and it influences the output of electrical power.One embodiment of the present of invention have been improved the performance of fuel cell 20 by the structural design channel field 72 of fuel cell 20.Usually, because fuel cell 20 utilizes sidepiece heat conduction to remove the heat that produces during energy produces, each bipolar plates 44 is worked under substantially invariable temperature, the one or more structure and the layouts that may influence channel field 72 in the following parameters: the optimization of water management (distribution of water partial pressure and the removal of aqueous water) optimization in the maximization of Nernst current potential on the membrane electrode assembly 62, the fuel cell pack 60, resistance and/or pressure consistency or pressure drop in single layer.

Fig. 2 G-2L is depicted as the example of the multiple channel field 72a-72g that is applicable to fuel cell 20.In one embodiment, the lip-deep channel field 72 that is set at adjacent bipolar plates 44 in the fuel cell 20 is distributed oxygen and hydrogen gas in the opposite direction, so that the maximization of the Nernst current potential of battery.

Shown in Fig. 2 G, the oxygen flow in the channel field 72a of the bottom (or top) of bipolar plates 44a 250 begins from the upper left corner, and 252 places finish in the lower right corner.At this moment, oxygen intake pipe road 106 provides fresh oxygen to the upper left corner 250, air exhaust duct road 108 (Fig. 2 E) oxygen air that 252 receptions consume from the lower right corner.Opposite, the hydrogen gas stream in the relative channel field 72b at the top (or bottom) of adjacent bipolar plates 44b 252 begins from the lower right corner, and 250 places finish in the upper left corner.Similarly, hydrogen admission line 102 provides fresh hydrogen to the lower right corner 252, hydrogen exhaust viewpoint 104 hydrogen that 250 receptions consume from the upper left corner.Flow pattern shown in Fig. 2 F is exemplary, be understandable that distribution oxygen that channel field 72a can be as described or opposite channel field 72a can anode distribute hydrogen, and channel field 72b distributes hydrogen to negative electrode.

Shown in Fig. 2 H, have the similar planar flow pattern among channel field 72c on the apparent surface of adjacent bipolar plates 44c and 44d and the 72d, but be to flow with opposite direction.More specifically, the flow of oxygen among the channel field 72c is in the beginning of the first 254a place in the bipolar plates 44c lower left corner 254, and 254 second portion 254b place finishes in the lower left corner.Between the starting and ending part of same corner, channel field 72c distributes oxygen along the path of the active region of the covering bipolar plates 44c of example on bipolar plates 44c.Opposite, the flow of oxygen among the channel field 72d is in the beginning of the second portion 254b place of the coupling in the bipolar plates 44d lower left corner 254, and the first 254a place of 254 coupling finishes in the lower left corner.At this moment, channel field 72d is identical with channel field 72c path, but direction is opposite.

Channel allocation pattern shown in Fig. 2 G and the 2H has been illustrated serial flow pattern, is along independent channel flow when wherein being flowing in each channel field 72a-d passed plate 44 and active region.Bipolar plates 44 of the present invention also can be utilized parallel channel field design, and wherein flowing is to carry out along a plurality of paths between the one or more shared mobile terminal of flow path.Shown in Fig. 2 I, the channel field 72e on the apparent surface of adjacent bipolar plates 44e and 44f has mutually antiparallel flow path with 72f.In particular, the flow of oxygen among the channel field 72e is in 256 beginnings of the upper right corner of bipolar plates 44e, and 258 finish in the lower left corner.The flow of oxygen of the slave plate 44e upper right corner 256 beginnings is divided into 6 substantially parallel passages 266 in total mobile terminal 264, and it passes plate 44e and oxygen is transmitted in the active region, and near total terminal 268 places of flowing the lower left corner 258 converge again.Opposite, the flow hydrogen gas of the upper left corner 257 beginnings of slave plate 44f is divided into 6 substantially parallel passages 267 at total flow disruption 265 places, and it passes plate 44f and oxygen is transmitted in the active region, and near total terminal 269 places of flowing the lower right corner 259 converge again.In this mode, the active region that channel field 72e and 72f pass bipolar plates 44e and 44f is transmitted in the opposite direction and is distributed hydrogen and oxygen.

Fig. 2 K is depicted as channel field 72i and the 72j on the apparent surface of adjacent bipolar plates 44i and 44j, wherein carries out " collaborative flowing " in identical direction.At this moment, channel field 72i begins and finishes flow of oxygen and flow hydrogen gas with 72j in an identical side of each plate 44.Fig. 2 L is depicted as channel field 72i and the 72k on the apparent surface of adjacent bipolar plates 44i and 44k, wherein carries out " collaborative flowing " in vertical direction.

The bipolar plates 44 of fuel cell 20 also can be used the combination of above-mentioned technology.For example, Fig. 2 J is depicted as channel field 72g and the 72g on the apparent surface of adjacent bipolar plates 44g and 44h, and it has utilized parallel design and design continuously respectively.

Bipolar plates 44 comprises substrate 89, and it represents one or more materials, forms passage 72 on substrate.Substrate 89 materials can change according to being used to.In one embodiment, substrate 89 comprises Heat Conduction Material.Below can be with reference to the advantage and the purposes of Fig. 3 A, 3B and 5 explanation heat conduction bipolar plates 44.In a specific embodiment, each plate 44 all is heat conduction, and the thermal conductivity of substrate is greater than 1W/mK.Heat-conducting substrate 89 can comprise metal for example aluminium or copper, perhaps comprises graphite composite material.Other is applicable to that the material of substrate 89 comprises 316SS or 316SSL stainless steel, 50/50 nichrome, titanium, Fe, Ni, Cr and alloy thereof.

In another embodiment, substrate 89 comprises electric conducting material.For example aluminium and copper are applicable to bipolar plates 44 to metal thus.Another kind of optional mode is that substrate 89 can comprise non-conductive material, for example silicon or glass.At this moment, plate 44 coated conductive layers, it increases the conductivity of bipolar plates 44.The substrate 89 of conductivity allows bipolar plates 44 to have basically less than the integral thickness of graphite composite plate, and it has reduced the thickness and the size of battery pile 60.

Bipolar plates 44 can also comprise one or more coatings that are applied on the substrate 89.For example, can add a coating and lose layer as ending of metal substrate.Suitable only erosion resisting coating can comprise such as non-corrosive polymeric matrices or pure polymeric material.

Bipolar plates 44 can also coated conductive metal alloy or polymeric material improve conductivity.Conductive coating a) is increased in substrate center part and comprise the plane conductivity of the bipolar plates 44 in the middle of the periphery of heat delivered annex 46 and b) improve the current delivery between bipolar plates 44 and the membrane electrode assembly 66.When plate 44 was made of non-conducting material, conductive coating was also as the electron conduction path.Conductive layer can comprise for example graphite, conductive metal alloy.In one embodiment, the plane conductivity of bipolar plates 44 is usually less than 100mOhm cm ², realize by electrically-conductive backing plate 89 or via the external conductive coating.

Can apply some coatings as ending the erosion layer and as conductive layer.For example, a kind of non-corrosive material with high conductivity both can increase conductivity, can be used as again to end the erosion layer.Similarly, a kind of and conductive adulterant for example the polymeric material that mixes of the carbon nano-tube of powdered graphite or different or similar size also can be not only as ending the erosion layer but also as conductive layer.Surface conductivity comprises most metals, conductivity ceramics and polymer, pure chemicals or alloy less than the corrosion-resistant finishes material of the conduction that is used for plate 44 of 100m Ω cm2.Some concrete examples comprise titanium carbide, titanium carbonitride, niobium, rhenium, titanium boride, chromium nitride, Au, Ni, Cu, Ti, CR, Mo and alloy thereof, conductivity ceramics, graphite composite material, and conducting polymer comprises polypyrrole, polyphenylene, polyaniline (polyanilne) etc., homopolymers and copolymer compound.

The relative little size of fuel cell 20 and bipolar plates 44 allows to use unconventional, relatively costly coating on bipolar plates 44.Relatively costly coating can comprise for example gold, titanium carbide, titanium nitride or composite material.The manufacturer of large scale fuel cell (more than the 2kW) generally avoids expensive pole plate coating owing to the expensive of a lot of square metres of coatings.Yet,, surpassed the cost of coating with the performance (augmented performance has reduced the overall dimensions of plate 44, the size that has reduced membrane electrode assembly 62 and the amount of required catalyst) of the low cost of the molded panel of whole plate and increase for small-sized fuel cell 20.For fuel cell 20, the use of the coating of gold and other high cost has further shown the novelty of fuel cell 20 with respect to traditional large-scale fuel cell technology thus, the area that uses gold on the pole plate in large-scale fuel cell is greater than two square feet, and its cost is very high.

Bipolar plates 44 can be by the multiple technologies manufacturing.In one embodiment, metal double polar plates 44 is made by the sheet metal micromechanics.Sheet metal also can be to form bipolar plates 44, passage 76 and flow field 72 through molded, casting, mold pressing or machining (for example milling).The favourable permission bipolar plates 44 of MEMs manufacturing technology is different with fuel cell ground and change feature along with fuel cell, and for example, changing channel field 72 shown in Fig. 2 G-2L like that can easily realize.In addition, other bipolar plates 44 for independent fuel cell pack 60, air inlet and exhaust manifold and gas ports can be positioned differently position, with the direction that adapts to concrete fuel cell 20 design or allow between plate 44 according to the path flow that designs (seeing the discussion for Fig. 2 F).

4, staggered passage

In one embodiment of the invention, bipolar plates 44 comprises " staggered " passage 76, and it a) reduces the thickness and/or the b of bipolar plates 44) reduce by adjacent bipolar plates 44 and be applied to by-local forces what on membrane electrode assembly layer 62 assembly.Fig. 4 A is depicted as the staggered passage 76 that is arranged on according to an embodiment of the invention on the bipolar plates 44.Fig. 4 B is depicted as bipolar plates 44c and the 44d that is arranged on according to another embodiment of the present invention on the membrane electrode assembly layer 62.Bipolar plate fuel battery heap 60 shown in Fig. 2 A also comprises staggered passage 76.

The degree of depth 270 of passage 76a by arrive with substrate Surface Vertical, that channel bottom 275 is passed of plate 44 or opening towards the distance decision of substrate.Shown in Fig. 2 A, at the facing surfaces 75a of single bipolar plates 44 and the passage 76a on the 75b and 76b to mutual skew so that when they pass substrate 89, passage 75a and 75b can not cross one another.Allow the passage 76a that is included among the 72a of first passage field on upper surface to have channel depth 270, the channel depth 272 of the passage 76b among the channel field 72b of its extend past on the apparent surface of same bipolar plates like this.The passage 76a of bipolar plates 44 lip-deep channel field 72a interlocks thus, makes them laterally can not block passage 72b among any channel field 72b (in-plane direction of 75a surfacewise).The depth value 276 of alternating share is that the channel bottom of a passage 76a approximately extends beyond the degree of depth in apparent surface's upper channel 76b channel bottom of total bipolar plates.Staggered depth value 276 can be represented by the numerical value of expection in the design or the mean values in manufacturing and the enforcement.

On the contrary, the bipolar plates 44 of Fig. 3 A is depicted as passage 76 traditional, noninterlace.At this moment, the ground of the channel vertical on the apparent surface of same bipolar plates 44 in line.Bipolar plates 44 thickness are confined at least so: the degree of depth that the degree of depth of a lip-deep passage adds the passage on the apparent surface adds the thickness of the baseplate material between two passages 76.For example, have 20 mil channel depth, the bipolar plates traditional, noninterlace of thick 10 mils of substrate 89 materials between two passages provides the bipolar plates of 50 mil thickness.Yet the staggered passage 76 shown in Fig. 4 B can stagger mutually, can make bipolar plates 44 thinner.For example, when being 10 mil interleave depths 276, the thickness of bipolar plates 44 with passage 76 of the 20 identical mil degree of depth is 30 mils, and it has saved 40% on thickness.For the fuel cell pack 60 with 50 bipolar plates 44, this makes fuel cell pack 60 and fuel cell 20 reduce 1 inch on thickness.

Staggered passage of the present invention allows bipolar plates 44 to comprise the passage 76b at channel bottom 275 extend past plates 44 middle parts thus.Usually, staggered passage 76 permission bipolar plates 44 of the present invention have the thickness 280 less than 2x, and wherein x is about degree of depth of each lip-deep passage of bipolar plates 44.In one embodiment, bipolar plates 44 of the present invention is included in having greater than the channel depth 270 of 10 mils and 272 passage 76 on each surface 75 of plate 44.At this moment, the thickness 280 of bipolar plates 44 is less than 20 mils.In another embodiment, it is lip-deep greater than the channel depth 270 of 20 mils and 272 passage 76 that bipolar plates 44 of the present invention is included in each of plate 44.At this moment, the thickness 280 of bipolar plates 44 is less than 40 mils.

Land regions 274 representatives and the transversal displacement of quantification between apparent surface 75a and 75b upper channel 76a and 76b on the surface 75 of plate 44.The thickness of the plate 44 between the apparent surface of the plane domain leap bipolar plates 44 in platform surface zone 274.When bipolar plates 44 was stacked in fuel cell pack 60, shown in Fig. 4 B and 2A, the relative passage 76 on the apparent surface of bipolar plates 44 (for example passage 76c and 76d) was staggered, makes them can not overlap.This allow platform surface zone 274 on the apparent surface of adjacent bipolar plates 44 in the opposite flank of membrane electrode assembly layer 62 to the overlapping of small part.

Channel width 277 is the plane width of passage 76 with respect to plate 44.In one embodiment, transversal displacement 274 (A) is directly proportional with the conductivity of battery pile 60 with respect to the ratio of channel width 277 (B).Some the time, A/B and maximum current density are inversely proportional to.The A/B ratio is suitable for a lot of purposes between about 1/10 to about 3.About 1/2 A/B ratio also is an acceptable.

The bipolar plates 44 of Fig. 3 A is depicted as passage 76 traditional, noninterlace, and wherein passage is substantially aligned.Fig. 3 A has exaggerated the thickness of membrane electrode assembly layer 62 for signal, in fact the thickness of Fig. 3 A usually is minimum (less than 1 millimeter), and compresses the passage 76 of adjacent bipolar plates 44 usually.For example, membrane electrode assembly layer 62 can comprise one or more submissive carbon-coatings as gas diffusion layers 122 and 124.Owing to the pressure on the layer that is applied to battery pile 60 by bolt 80 can surpass 100psi, the membrane electrode assembly layer can easily be pressed in the passage 76, be compressed, pushes and be damaged.

On the contrary, among Fig. 4 B the platform surface on adjacent bipolar plates 44c and 44d zone 274c and 274d overlapping to small part on one or more side surface direction 91 on plate 44 surfaces.This provides the contact side surface 93 that membrane electrode assembly 62 has between plate 44c and 44d.This total surface has increased the surface area of the contact between the adjacent panels 44, allows to carry out mechanical support jointly and has reduced pressure between bipolar plates 44c and the 44d.Reduced the local stress on the membrane electrode assembly layer 62 like this.

In one embodiment, Gong You side surface 93 comprise the surface area of passage 76c on the plate 44c and the nearest bipolar plates 44c between the passage 76d on the plate 44d at least half.In another embodiment, Gong You side surface 93 comprises at 10 of the surface area of the bipolar plates 44c between the two adjacent passages 76 on the plate 44c at least.

5, mobile buffer

The present invention also provides such bipolar plates, and it comprises that the buffer that flows improves the transmission of reacting gas and removing of product.Fig. 2 E is depicted as the mobile buffer 150 that is used to improve gas flow according to an embodiment of the invention in fuel cell.Plate 44 comprises the channel field 72 that is divided into four groups of passage 76e-76i.Every group of passage comprises a plurality of straight substantially and substantially parallel passages 76.

Bipolar plates comprises four buffer 150a-d.The buffer 150a that flows is used for receiving oxygen from four manifold passage 76e from oxygen inlet manifold 106 reception oxygen.Manifold passage 76e provides gas communication between mobile buffer 150a and oxygen manifold 106.The buffer 150a that flows also is used for five passage 76f output oxygen of the width of straddle 44 sidelong, and provides gas communication between mobile buffer 150a and mobile buffer 150b.The buffer 150b that flows be used for from five passage 76f receive oxygen and to five passage 76g output oxygen (via passage 76f than passage 76g high pressure).The buffer 150c that flows is used for receiving oxygen and exporting oxygen to five passage 76h from five passage 76g.The buffer 150d that flows is used for receiving oxygen and exporting oxygen to three passage 76i from five passage 76h, and it provides oxygen to output manifold 108.

Because each passage 76 of bipolar plates 44 cathode sides is also collected the water that electrochemical reaction produces, each passage 76 shown in Fig. 2 E also is used to collect exhaust gas products.The buffer 150 that flows thus also promotes to remove accessory substance from membrane electrode assembly 62.In addition,, be understandable that the relative side of bipolar plates 44 also can comprise one or more buffers 150, improve the gas flow of anode-side and the transmission of hydrogen though described mobile buffer 150a-d with respect to the cathode side of bipolar plates 44.

The buffer 150 that flows provides the total storage area that is used for flow of oxygen between the passage 76, and provides more stable gas flow to each channel field 72.If individual other passage 76 gets clogged or runs into pressure disturbance or fluctuation, downstream buffer 150 makes the minimum interference to the downstream that is caused by pressure disturbance.Downstream 150c is by allowing to provide among the gas passage group 76g four other passages 76 to provide gas to whole five passages to buffer 150c, and the pressure of eliminating in the individual channels 76 in channel group 76g changes.Traditional, continuous crossing of passage have the many places bending plate most and be used for the major part of a membrane electrode assembly.When getting clogged, whole downstream parts of this continuous passage all are affected, and cause the major part of membrane electrode assembly to lack gas transmission and function (if especially blocking when taking place very early) thereof.Opposite, if a passage 76 among the channel group 76g gets clogged or is changed, the gas of accumulating in the buffer 150c that flows prevents the gas supply of local dip influence to the remainder of plate 44.The buffer 150c that flows has certain taking in, and it reduces the pressure differential between other passage among the passage 76 that gets clogged and the channel group 76g before the 76 output oxygen of the passage in channel group 76f.In one embodiment, mobile buffer has 10 times capacity of an independent flow channel.For the mobile buffer 150 that has with flow channel 76 same depth, mobile buffer then can comprise the surface area of 10 times of single flow channels.When mobile buffer 150 has the identical degree of depth with flow channel 76, also can use the ratio between passage 76 thickness (d) and the buffer thickness (D).From about 1/2 to about 1/20 thickness proportion (d/D) is suitable for some purposes.

In addition, the upstream buffer also helps to overcome pressure disturbance or the fluctuation in passage, and is passive to other passage supply gas by changing according to pressure.In the example in front, if in the passage 76 gets clogged or is changed among the channel group 76g, buffer 150b increases owing to the obstruction of upstream runs into pressure, makes other four passages 76 among the downward admission passage group of the gas 76g.Block although exist, buffer 150c still is under the essentially identical pressure.

Minimize by the influence that makes the local pressure disturbance, buffer 150 thus balance the distribution of pressure, and the pressure that has reduced bipolar plates 44 active regions changes.This provides the performance of fuel cell 20.Though the bipolar plates 44 shown in Fig. 2 E comprises four mobile buffers 150, be understandable that bipolar plates 44 can comprise more or less buffer 150 according to the design of channel field 72.In one embodiment, bipolar plates 44 comprises 1 to 10 buffer 150.

6, heat management

The present invention has also improved the heat management of fuel cell.In order to reach this purpose, bipolar plates can comprise one or more heat delivered annexes.Fig. 2 E is depicted as the schematic diagram of the bipolar plates 44 that comprises a heat delivered annex 46.Fig. 3 A is depicted as the schematic cross-section that comprises the fuel cell pack 60 of a heat delivered annex 46 according to one embodiment of the invention on each bipolar plates 44.Fig. 3 B is depicted as the schematic cross-section of heat delivered annex 46 and plate 44 according to an embodiment of the invention.Fig. 2 A is depicted as the schematic cross-section of the fuel cell pack 60 that comprises two heat delivered annexes 46 on each bipolar plates 44.

Heat delivered annex 46 allows the external heat management is carried out in the inside of fuel cell pack 60.More specifically, annex 46 can be used for heating or the inside of cooled fuel cell heap 60, for example each bipolar plates 44 and any adjacent membrane electrode assembly layer 62.Heat delivered annex 46 is arranged in the outside of channel field 72 at sidepiece.Sidepiece is arranged position or the arrangement that is meant with respect to the plane surface of plate 44.The planar alignment that plane coordinates for example helps characterization board 44 at the lip-deep rectilinear coordinates 91a and the 91b (Fig. 2 E) of plate 44.Thus, the sidepiece of channel field 72 outsides is arranged and to be meant the heat delivered annex 46 that is arranged at the outside of channel field 72 according to plane coordinates 91a and 91b.In one embodiment, annex 46 is set at the outside of bipolar plates 44.The outside of bipolar plates 44 comprises any part of the plate 44 that is close to side that is included in the substrate in the plate 44 or edge.The outside of bipolar plates 44 does not generally comprise channel field 72.For the embodiment shown in Fig. 2 E, heat delivered annex 46 basic sides that do not comprise inlet manifold and exhaust manifold 102-108 across plate 44.For the embodiment shown in Fig. 2 A, plate 4 comprises two heat delivered annex 46a and 46b, and it does not comprise the both sides of gas manifold substantially across plate 44.

Putting heat delivered annex 46 in outer periphery allows to carry out control transfer of heat via substrate 89 between the annex 46 of the inside of plate 44 and externally setting.Heat conduction be meant be in contact with one another or form heat delivered between the as a whole body.Thus, the conduction of the sidepiece of the heat that carries out between the core of the outside of plate 44 and bipolar plates 44 is carried out via substrate 89.In one embodiment, heat delivered annex 46 forms as one in plate 44 with the material of substrate 89.At this moment the whole continuity that is meant the material between annex 46 and the plate 44.Integrally formed annex 46 can be molded by a sheet metal is carried out once with plate 44, punching press, machining or MEMs handle and form.Integrally formed annex 46 and plate 44 allow to carry out heat conduction and heat delivered via substrate 89 between the inside of plate 44 and heat delivered annex 46.In another embodiment, annex 46 comprises and is different from the material that is used to be attached to the substrate 89 on the plate 44, and thermal conduction communication and heat delivered take place the junction between two kinds of attached materials.

Heat can pass to heat delivered annex 46 or constitute heat delivered annex 46.In other words, annex 46 can be used as heat dissipation equipment or thermal source.Thus, heat delivered annex 46 can be used as the inside that heat dissipation equipment cools off bipolar plates 44 or membrane electrode assembly 62.Fuel cell 20 utilizes coolant to remove heat from annex 46.Another kind of optional mode is that heat delivered annex 46 can be used as thermal source provides heat to the inside of bipolar plates 44 or membrane electrode assembly 62.At this moment, catalyst is set when heat medium exists, to produce heat on annex 46.

For cooling, heat delivered annex 46 allows the inside of slave plate 44 integrally to conduct heat to the annex 46 of outer setting.During hydrogen consumption and electrical power generation, the geo-electrochemistry reaction produces heat in each membrane electrode assembly 62.Because the inside of bipolar plates 44 contacts with membrane electrode assembly 62, heat delivered annex 46 on the bipolar plates 44 cools off the membrane electrode assembly 62 adjacent with plate thus, via a) conducting heat and b from membrane electrode assembly 62 to bipolar plates 44) carry out outside heat conduction and heat delivered from core to the outside of the plate 44 that comprises annex 46 with membrane electrode assembly 62 contacted bipolar plates 44.At this moment, heat delivered annex 46 is from the substrate between the second channel field 72 on another apparent surface 75 of first passage field 72 on the surface 75 of plate 44 and plate 44 89 heat radiation, with direction that the surface 75 of plate 44 parallels on conduct heat to the heat delivered annex.When fuel cell pack 60 comprises a plurality of membrane electrode assembly layer 62, pass through the sidepiece heat conduction of each bipolar plates 44 by this way, the core that is provided at the interlayer cooling-fuel cell pack 60 between a plurality of membrane electrode assembly layers 62 in the fuel cell pack 60 comprises these layers.

Fuel cell 20 utilizes the coolant of the heat delivered annex 46 of flowing through.This coolant receives and removes heat from annex 46.The heat that produces in fuel cell pack 60 is transmitted to annex 46 through bipolar plates 44 thus, and via transfer of heat heated cooling medium between annex 46 and coolant.Air is suitable for use as this coolant.

Shown in Fig. 3 B, heat delivered annex 46 can have less than 44 liang of the plates thickness 194 of thickness 196 between the surface 75 relatively.In one embodiment, thickness 194 is less than half of about thickness 196.In another embodiment, thickness 194 approximately is 1/3rd of thickness 196.On the adjacent bipolar plates 44, the thickness that is reduced of annex constitutes passage 190 (seeing Fig. 3 A) in fuel cell pack 60.A plurality of adjacent bipolar plates 44 in the battery pile and annex 46 constitute a plurality of passages 190.Each passage 190 allows coolant to flow through and process heat delivered annex 46.In one embodiment, fuel cell pack 60 comprises mechanical hull 197, its sealing and protection battery pile 60 (see figure 5)s.The wall 199 of housing 197 also provides the additional pipeline of thermal medium by form pipeline between adjacent appendages 46 and wall 197.

Coolant can be gas or liquid.The heat delivered that obtains by high-termal conductivity bipolar plates 44 allows air to come cooling heat transmission annex 46 and battery pile 60 as coolant.For example, a dc fan can be attached on the outer surface of mechanical hull.This blower fan makes air enter through the hole on the mechanical hull, and through passage 190 cooling heats transmission annex 46 and fuel cell pack 60, steam vent on mechanical hull or exhaust end flow out.The amount of the heat that the adjustable-speed joint that improves or reduce cooling blower is removed from battery pile 60 and the operating temperature of battery pile 60.In 60 1 embodiment of fuel cell pack of air-cooling, cooling blower speed increases or reduces actual negative electrode discharge temperature with respect to temperature required set point.

The heat conduction of process bipolar plates 44 and the high-termal conductivity in each bipolar plates 44 provide the hot consistency of the improvement of battery pile 60.In one embodiment, the thermal conductivity of each bipolar plates is greater than 1W/mK.For instance, the high-termal conductivity in this scope makes and be temperature gradient less than 2 to the maximum between each plate 44.The heat conduction of process bipolar plates 44 has increased the thermal stability of battery pile 60 thus, and it has improved the performance and the life-span of fuel cell 20.Heat delivered annex 46 also makes battery pile 60, and traditional that the fuel cell pack size that the method for removing thermosphere at interval obtains is set between bipolar plates 44 is littler with respect to utilizing.

For heating, heat delivered annex 46 allows to transmit heat from the annex 46 of outer setting to the inner body of plate 44.The electrochemical reaction that consumes hydrogen and produce electrical power generally needs higher temperature.Usually need be greater than 150 degrees centigrade initial temperature.

In one embodiment, fuel cell comprises and is arranged in the heat delivered annex 46 or catalyst 192 adjacent thereto.When flowing through catalyst 192, heat medium produces heat.Typically, catalyst 192 and heat medium utilize heat-producing chemical reaction to produce heat.Heat delivered annex 46 and plate 44 then with heat delivered in fuel cell pack 60 for example, with heating internal membrane electrode assemblie layer 62.For example, catalyst 192 can comprise platinum, and heat medium comprises the hydrocarbon fuel sources 17 (Figure 1A) that is fed to fuel processor 15.In one embodiment, fuels sources 17 was heated before entering fuel cell 20, and entered fuel cell 20 as gas.Similar with aforesaid coolant, be arranged on blower fan on one of wall 199 and remove gaseous state heat medium in the housing 197.In a specific embodiment, be used for and the hydrocarbon fuel sources 17 of catalyst 192 reaction reformation waste gas from fuel processor 15.This advantageously preheating enter fuels sources 17 before the fuel cell 20, and after being utilized, utilized or burnt to remain in any fuel in the reformation waste gas by fuel processor 15.Another kind of optional mode is, fuel cell 20 comprises that the hydrocarbon fuel sources 17 of separation supplies with, and it is directly to fuel cell 20 supply hydrocarbon fuel sources 17, be used for heating and with catalyst 192 reactions.Other appropriate catalyst 192 comprises palladium, platinum/palladium mixture, iron, ruthenium and combination thereof.In these each will produce heat with hydrocarbon fuel sources 17 reactions.Other suitable thermocatalyst 192 comprises platinum on the aluminium oxide for example and the platinum/palladium on the aluminium oxide.

Shown in Fig. 2 A, catalyst 192 is set at each heat delivered annex 46b and goes up and be in contact with it.At this moment, heat medium reacts through each annex 46 and with catalyst 192.Produce heat like this, heat absorbs via the heat conduction of cooling attachment 46.Flushing type applies to be used on each annex 46 catalyst is set.Ceramic monolith also can be used for bonding catalyst 192 on annex 46.

Fig. 5 A is depicted as two examples, and wherein thermocatalyst 192 is set up and approaches heat delivered annex 46.At this moment near being meant the near-thermal amount transmission annex 46 that connects, so that the heat that is produced by catalyst 192 passes to annex 46 by conduction or convection current and/or radiation.Shown in Fig. 5 A, fuel cell 20 comprises wall 195, and it comprises catalyst 192.Wall 195 contacts (for example via such as the kapton adhesive tape) and is formed for holding the space of catalyst 192 and each annex 46 with end plate 64.192 of catalyst granuless are set on the wall 195.This wall 195 allows the heat medium process and reacts with catalyst 192.Figure 5 shows that end view through the gas flow of wall 195.Before mixed gas flow was crossed heat delivered annex 46, air and fuel entered mixing chamber 191.Then discharging gas with catalyst 192 reaction backs from one or more ports of export.

Shown in Fig. 2 A, fuel cell 20 comprises mechanical hull 197, its sealing and protection battery pile 60.The wall 199 and the annex 46 of housing 197 are combined into pipeline 193.Inside-annex pipeline 193 allows a) catalyst 192 pack into pipeline 193 and b) allow flow through pipeline 193 and of heat medium through catalyst 192.At this moment, catalyst 192 is loaded into pipeline 93, its loading density be enough loose with allow gas through and can not run into extra resistance.Utilize a blower fan to provide heat medium then to pipeline 193.

For heating based on catalyst, heat is followed a) and is transferred to annex 46 from catalyst 192, b) core that contacts with membrane electrode assembly layer 62 to bipolar plates 44 from the sidepiece of the plate that comprises heat delivered annex 46 through heat conduction, from sidepiece flow through bipolar plates 44 and c) from bipolar plates 44 to 62 conduction of membrane electrode assembly layer.When fuel cell pack 60 comprises a plurality of membrane electrode assembly layer 62, provide the heating of the internal layer between 60 kinds of a plurality of membrane electrode assembly layers 62 of fuel cell pack through the sidepiece heating of each bipolar plates 44, it has quickened the preheating of fuel cell.

Bipolar plates 44 shown in Fig. 2 A is included in the heat delivered annex 46 on each side.At this moment, one group of heat delivered annex 46a is used for cooling, and another group heat delivered annex 46b is used for heating.Though the heat delivered annex 46 shown in Fig. 5 A has via two kinds of catalyst 192 dissimilar heating (promptly, by entering pipeline 193 and being stored on the wall 195), be understandable that fuel cell 20 needn't comprise the several different methods of heat delivered annex 46, and can comprise one of aforementioned techniques.In addition, though being depicted as, the bipolar plates 44 shown in Fig. 2 A and Fig. 3 A only has the plate 44 that one or two is arranged on the heat delivered annex 46 on battery pile 60 sides, but the arrangement of annex 46 can change according to other special design, to influence and to improve the heat dissipation and the heat management of fuel cell pack 60.For example, can use plural heat delivered annex 46 to come reinforcement plate 44 heat delivered between inside and outside on the plate 44.In addition, annex 46 does not need a side across plate as illustrated, can how to design by housing 197 according to the fluid of heating yet.

7, seal between the plate of Gai Shaning

The present invention has also improved the sealing of adjacent bipolar plates 44.For the description of Fig. 2 E, plate 44 comprises hermetic unit 87 as above, and its periphery at each plate 44 surrounds channel field 72.Hermetic unit 87 surrounds channel field 72 and surrounds manifold 102-108 in the periphery of plate 44.Hermetic unit 87 diaphragm seal electrode assemblie layer 62 and manifold 102-108.

When the match surface that will seal is plane and when not having with plane or the supporting cross one another structure of installation substantially, good seal.For the bipolar plates 44 shown in Fig. 2 E, extending out from manifold 102 seals around sealing around the manifold 102 and channel field 72 towards the continuous part that the manifold passage 76e of buffer 150a prevents surperficial 75a.

Fig. 7 A is depicted as the schematic diagram that comprises the bipolar plates 44 of packing ring platform 400 according to one embodiment of present invention on the hermetic unit 87 of plate.Fig. 7 B is depicted as the close-up view of 400a.The upper surface 75a that packing ring platform 400a-d is set at plate 44p goes up and surrounds in the periphery manifold on surperficial 75a.On the lower surface of plate 44, also has similar platform.Term described here, packing ring platform 400 are meant the part that has the continuous level passage on plane 75 of bipolar plate surfaces 75.General, these packing ring platform 400 passages reach periphery sealing completely thus at the whole peripheral manifold that surrounds of manifold.For example, packing ring platform 400a fully surrounds the plane periphery of hydrogen inlet manifold 102 on the surperficial 75a of plate 44p, packing ring platform 400b fully surrounds the plane periphery of cathode exhaust manifold 108 on the surperficial 75a of plate 44p, packing ring platform 400c fully surrounds the plane periphery of anode off-gas manifold 104 on the surperficial 75a of plate 44p, packing ring platform 400d fully surrounds the plane periphery of oxygen inlet manifold 106 on the surperficial 75a of plate 44p

When bipolar plates 44p and 44q adjacent one another are be stacked the time, each platform 400 provides continuous and continual plane contact between the apparent surface of plate 44p and 44q.Shown in Fig. 7 C, packing ring 406 is set between the platform 400 of adjacent panels 44p and 44q.Pressure from bolt 82 and end plate 64 (Fig. 2 A) is then compressing between the plate 44 and between the continuous platform 400.The material of packing ring 406 can comprise and is selected from following high temperature and chemically stable material: silicone, poly-(tetrafluoroethene) (Teflon PTFE), poly-(perfluoro alkoxy) (Teflon PFA), PEP (FEP), polyvinylidene fluoride (PVDF), polysiloxanes (silicon rubber/sealant), polyimides (Kapton), polyamide (nylon), polyester (Mylar), epoxy, polyphenylene oxide (PPO), sulfonated poly (phenylene oxide), the polystyrene oxide, polymethacrylates, polyether-ether-ketone (PEEK) and copolymer and mixture.Packing ring 406 can come the asymmetrical geometry of mounting platform 400 by silk screen printing.This gasket materials also can be processed by the overmolding of die-cut packing ring film, directly silk screen printing, spraying, casting or high-performance packing ring solution.

As mentioned above, the substrate 89 at hermetic unit 87 places also can raise with respect to the substrate 89 of plate 44 cores, and does not use packing ring between plate 44.At this moment, when being forced together by bolt 82 and base plate 64, the platform 400 of adjacent panels 44 seals, and does not need to be provided with packing ring.

In order to form platform 400, each plate 44 comprises manifold passage 402, and a) opening is towards manifold for it, and b) substrate of leap bipolar plates 44 from upper surface 75a to lower surface 75b c) is used for transmitting gas between manifold and channel field.Fig. 7 D is depicted as the end view of the 44q of bipolar plates 44p and the manifold passage 402a by plate 44p.Fig. 7 E is depicted as the end view of the 44q of bipolar plates 44p and the manifold passage 402d by plate 44q.As shown in FIG., enter manifold 104, turn over 90 degree downwards and extend to lower surface 75b from upper surface 75a at upper surface 75a manifold passage 402a opening, and along arrive to flow passage in the channel field on buffer 150 or the lower surface 75b of lower surface.Similarly, enter manifold 104, turn over 90 degree downwards and extend to lower surface 75b, and arrive passage 76 in the channel field on the lower surface 75b along lower surface from upper surface 75a at the upper surface 75a of plate 44q manifold passage 402b opening.Thus, each manifold passage 402 begins gas flow on a surface, gas is delivered to another surface of plate 44.Though the manifold 402 shown in Fig. 7 E and the 7F comprises the orthogonal dimension between the surface 75, also can have other structure, for example fillet or non-90 is spent corners.

By making passage 402, between two lip-deep channel field of manifold and plate 44, form plane space through plate.This plane space is formed in continuous platform 400 surfaces around each manifold.Thus packing ring platform 400 avoided with each surface 75 on manifold passage 402 intersect mutually.Opposite, manifold passage 402 has been avoided intersecting mutually with packing ring platform 400 on two surfaces of the plate 44 that forms this manifold passage.

As shown in FIG., each manifold transmits gas to three manifold passage 402.Passage 402 is intermeshing to prevent that the passage on the adjacent panels overlaps when plate 44p and 44q are adjacent one another are in battery pile 60 at sidepiece between adjacent plate 44p and the 44q.Fig. 7 C is depicted as the cross sectional view of the front portion of bipolar plates 44p and 44q, wherein shows the staggered of manifold passage 402a-f around on plate 44p and the 44q manifold 104.

8, prebuckling end plate

Get back to Fig. 2 A, the action need pressure of membrane electrode assembly layer 62.Battery pile 60 is utilized bolt 82a and 82b to compress on top end plate and bottom end plate 64a and 64b and is exerted pressure.The pressure that is provided at the plane domain of membrane electrode assembly layer 62 by end plate 64 has been provided for fastening bolt 82a and 82b.Bolt 82 makes battery pile 60 be fixed together under the compression of end plate 64 thus.Utilize flat end plate 64 to cause the pressure distribution inequality on membrane electrode assembly layer 62 in the fuel cell pack 60 through regular meeting.More specifically, bolt 82 apply around the local pressure place or near battery pile 60 in pressure usually greater than the pressure of battery pile central plane part.This pressure changes the performance that can influence fuel cell 20.For the pressure that reduces in the battery pile 60 changes, Fig. 6 illustrates prebuckling end plate 64a and the 64b that is applicable in the fuel cell 20 according to an embodiment of the invention.

Top end plate and one of bottom end plate 64a and 64b are endowed certain shape before in being assembled into fuel cell 20, when top end plate 64a and bottom end plate 64b were fixed together, its increase was applied to the pressure of the central plane part of membrane electrode assembly layer 62." prebuckling " end plate, term described here are meant the end plate 64 that was endowed definite shape before assembling, and when top end plate 64a and bottom end plate 64b were fixed together in fuel cell pack 69, it flattened substantially.Prebuckling end plate 64 is curved so that the assembly of battery pile 60 has the pressure that is increased the center plane region of battery pile 60 by end plate 64 applied pressures before supporting in big 60 being assembled into inlet, bolt 82 with respect to and the planar section of the nearer membrane electrode assembly 62 of bolt 82 between.Having reduced the applanation that runs through membrane electrode assembly 62 in the fuel cell pack 60 like this changes.

As shown in FIG., prebuckling end plate 64a and 64b have a convex curvature before assembling, and when top end plate and bottom end plate 64 were fixed together, convex curvature reduced.For one dimension convex curve shown in Figure 6, bolt 82 passes the hole on each end plate 64 opposite flank.Be applied to pressure on the central plane by adding king-bolt 82, this curature variation is at the local pressure of each end of prebuckling end plate 64.Originally, the shape of prebuckling end plate 64 causes the pressure of the central plane part of each membrane electrode assembly 62 in the fuel cell pack 60 to increase.Fastening along with bolt 82, the convex curvature of plate 64 reduces.In addition, the proportional less pressure of convex curvature from each bolt 82 to the central plane of membrane electrode assembly layer 62.When whole bolt 82 complete when fastening, the pressure of the part that the pressure balance membrane electrode assembly 62 of the central plane part of each membrane electrode assembly layer 62 and bolt 82 are contiguous.Reduced the variation of membrane electrode assembly layer 62 and battery pile 60 midplane pressure like this.

Applanation variation in membrane electrode assembly layer 62 reduces, the battery pile 60 that assembling prebuckling end plate 64 causes producing as shown in Fig. 2 A in fuel cell pack 60.Prebuckling end plate 64 keeps together bipolar plates 44 and membrane electrode assembly layer 62 thus, and exerts pressure on the plane domain of each bipolar plates 44, and each membrane electrode assembly layer 62 has the applanation variation that reduces.

One or two end plate 64a and 64b can be shaped by prebuckling or before assembling.For the plate of bending, the flexibility of each end plate 64 is used for making the applanation minimize variations of membrane electrode assembly layer 62 of fuel cell pack 60.The material of the thickness of end plate 64, end plate 64 and the required flexibility that is applied to each end plate 64 of pressure influence on the battery pile 60.In one embodiment, end plate has the thickness from about 1/2mm to about 3mm.End plate 64 can comprise suitable rigid material, for example stainless steel, titanium, aluminium, composite material or pottery.In one embodiment, the operating pressure of each membrane electrode assembly 62 utilization from about 30psi to about 400psi.Approximately the operating pressure of 100psi also is applicable to the design of some battery pile 60.

9, conclusion

Though invention has been described with reference to a plurality of embodiment, the multiple replacement in abridged in this manual, conversion and equivalent way also fall within the scope of the invention in order to simplify purpose.For example, though have prebuckling end plate 64 in the some embodiments of the present invention, be not that all embodiment of the present invention need to comprise prebuckling end plate 64, but can utilize the end plate on traditional plane yet.In addition, be used for the one or more mobile buffer that balanced gas distributes, comprise that the bipolar plates of heat delivered annex also can not need the buffer that flows though have in the some embodiments of the present invention.Therefore, scope of the present invention should limit with reference to appending claims.

Claims (11)

1, a kind of fuel cell that is used to produce electric energy, described fuel cell comprises:

A) one group of bipolar plates, each bipolar plates comprises i) substrate, it has first passage field that is arranged on the substrate first surface and the second channel field that is arranged on the substrate second surface, the first passage field comprises one group of passage that is used to distribute oxygen, the second channel field comprise second group be used to distribute the passage of hydrogen and ii) with the substrate thermal conduction communication, be arranged on the first passage heat delivered annex of portion outside the venue;

B) thermocatalyst is arranged to contact with the heat delivered annex or contiguous heat delivered annex, and generation heat when being exposed to heat medium in the time; With

C) be arranged on two membrane electrode assemblies between the bipolar plates, this membrane electrode assembly comprises hydrogen catalyst, oxygen catalyst and the ion-conductive membranes that hydrogen catalyst is separated with the oxygen catalyst electricity.

2, fuel cell according to claim 1, wherein thermocatalyst is arranged on one or more heat delivered annexes of bipolar sheetpile.

3, fuel cell according to claim 1, the thickness of heat delivered annex is littler than the thickness of the substrate between first surface and the second surface.

4, fuel cell according to claim 1 further comprises the next door that thermocatalyst is housed, and wherein said next door is attached on the heat delivered annex.

5, fuel cell according to claim 1, wherein thermocatalyst is filled near the heat delivered annex.

6, fuel cell according to claim 1, wherein heat medium comprises the hydrocarbon fuel sources that is provided to fuel processor, and fuel processor is isolated hydrogen and hydrogen is offered fuel cell from hydrocarbon fuel sources.

7, fuel cell according to claim 6, wherein said hydrocarbon fuel sources is from the waste gas of fuel processor.

8, fuel cell according to claim 1, wherein said thermocatalyst comprises platinum.

9, fuel cell according to claim 1, wherein said substrate has the thermal conductivity greater than 1W/mK.

10, fuel cell according to claim 1, wherein said substrate comprises metal.

11, fuel cell according to claim 1, wherein the heat delivered annex is used in the direction parallel with first surface, dispels the heat to the heat delivered annex from the substrate between first passage field and the second channel field.

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