EP3430662A1 - Bipolar plate having a variable width of the reaction channels in the inlet region of the active region, fuel cell stack and fuel cell system having bipolar plates of this type, as well as a vehicle - Google Patents

Bipolar plate having a variable width of the reaction channels in the inlet region of the active region, fuel cell stack and fuel cell system having bipolar plates of this type, as well as a vehicle

Info

Publication number
EP3430662A1
EP3430662A1 EP17731159.4A EP17731159A EP3430662A1 EP 3430662 A1 EP3430662 A1 EP 3430662A1 EP 17731159 A EP17731159 A EP 17731159A EP 3430662 A1 EP3430662 A1 EP 3430662A1
Authority
EP
European Patent Office
Prior art keywords
fuel cell
channels
width
region
active region
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP17731159.4A
Other languages
German (de)
French (fr)
Inventor
Hannes Scholz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Audi AG
Volkswagen AG
Original Assignee
Audi AG
Volkswagen AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Audi AG, Volkswagen AG filed Critical Audi AG
Publication of EP3430662A1 publication Critical patent/EP3430662A1/en
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0258—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant
    • H01M8/0265—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant the reactant or coolant channels having varying cross sections
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0206—Metals or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0213—Gas-impermeable carbon-containing materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0267—Collectors; Separators, e.g. bipolar separators; Interconnectors having heating or cooling means, e.g. heaters or coolant flow channels
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H01M8/04119—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
    • H01M8/04126—Humidifying
    • H01M8/04134—Humidifying by coolants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M2008/1095—Fuel cells with polymeric electrolytes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2250/00—Fuel cells for particular applications; Specific features of fuel cell system
    • H01M2250/20—Fuel cells in motive systems, e.g. vehicle, ship, plane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H01M8/04119—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/40—Application of hydrogen technology to transportation, e.g. using fuel cells

Definitions

  • the invention relates to a bipolar plate for a fuel cell, the two profiled
  • Separator plates has, each having an active area and two manifold areas for supply and discharge of reaction gases and coolants to or from the active area, the separator plates are formed such that the bipolar plate has separate channels for the reaction gases and the coolant, which ports for
  • Reaction gases and coolant both distribution areas connect together and each formed as an open channel-like channel structures, the two profiled
  • Separator plates are arranged one above the other, that in the adjacent sides through the channel structures coolant channels are formed, a
  • Fuel cell stack a fuel cell system and a vehicle.
  • Fuel cells use the chemical transformation of a fuel with oxygen to water to generate electrical energy.
  • fuel cells contain as core component the so-called membrane electrode assembly (MEA for membrane electrode assembly), which is a composite of an ion-conducting, in particular proton-conducting membrane and in each case an electrode arranged on both sides of the membrane (anode and cathode).
  • MEA membrane electrode assembly
  • GDL gas diffusion layers
  • the fuel cell is formed by a multiplicity of stacked MEAs whose electrical powers add up.
  • the fuel in particular hydrogen H 2 or a hydrogen-containing gas mixture
  • the anode where an electrochemical oxidation of H 2 to H + takes place with emission of electrons.
  • an electrochemical oxidation of H 2 to H + takes place with emission of electrons.
  • the electrolyte or the membrane which separates the reaction spaces gas-tight from each other and electrically isolated, takes place (water-bound or anhydrous) transport of protons H + from the anode compartment in the cathode compartment.
  • the electrons provided at the anode are supplied to the cathode via an electrical line.
  • the cathode is supplied with oxygen or an oxygen-containing gas mixture, so that a reduction of 0 2 to O 2 " taking the Electrons take place.
  • these oxygen anions in the cathode compartment react with the protons transported via the membrane to form water.
  • the fuel cell is formed by a plurality of membrane-electrode units arranged in the stack, so that it is also referred to as a fuel cell stack. Between two membrane-electrode units, a bipolar plate is in each case arranged, which is a supply of the individual cells with the operating media, ie the reactants and a
  • the bipolar plates provide an electrically conductive contact to the membrane-electrode assemblies. Furthermore, they ensure a tight separation between anode and cathode space.
  • the bipolar plates are usually constructed of two profiled electrically conductive Separatorplatten, which arranged a structure in the form of either side of the plates
  • Operating media are in turn separated by the plates so that inside the plate the coolant is passed while outside the reactant gases are conducted.
  • the channels of the reactant gases are limited on the one hand by the respective plate and on the other by a gas diffusion layer.
  • a bipolar plate is known from DE 10 2008 033 21 1 A1, in which the width of the channels of a reaction gas and the webs lying therebetween is continuously varied.
  • the invention is based on the object, a bipolar plate and a
  • a bipolar plate for a fuel cell which has two profiled separator plates, each having an active region and two distributor regions for the supply and discharge of reaction gases and coolants
  • the bipolar plate according to the invention is characterized by the following configurations of the channel structures:
  • the channels for a reaction gas or both reaction gases have a smaller width in an inlet region of the active region than in the remaining partial region of the active region, the width of the channels increasing continuously from the beginning to the end of the inlet region.
  • channel width and land width represents a channel land unit and is also referred to as a "channel pitch”.
  • the width of the reaction gas channels in the region of the gas inlet is reduced in the active area, as it is provided in the other active area and thus increased the width of the webs between the reaction gas channels, so that the reaction gases and the product water in less Extent through the GDL diffuse, and thus sets a higher humidity difference between the membrane and reaction gas channels.
  • the inlet region occupies 5 to 30%, preferably 10 to 25% and particularly preferably 20% of the active region, so that the membrane is already sufficiently moistened at the beginning of the active region and at the same time an excessive moistening in the further course of the active Area is avoided.
  • the width of the channels or of the webs can be adjusted from the beginning to the end of the
  • Entry area continuously or discontinuously be designed increasingly.
  • the channel width in the entry region is smaller than in the remaining active region, but constant, and that the channels widen only upon entry into the remaining region of the active region.
  • a short transition region can be provided, which avoids a step in the channels.
  • bipolar plate can be implemented advantageously in metallic or graphitic bipolar plates.
  • the invention can be preferably used to control the humidification of the cathode gas, but it is also suitable for the control of the humidity of the anode gas. Likewise, both reaction gases can simultaneously by a
  • Embodiment of the inlet region of the bipolar plate with respect to the humidification can be influenced.
  • Velocity distribution in the anode and cathode gas channels optimized in the active region of the bipolar plate means that as far as possible over the entire active area uniform pressure conditions, uniform humidification of Reactants and the membrane and same flow rates are present.
  • the performance and service life of the fuel cell stack are advantageously increased thereby.
  • the fuel cell stack according to the invention comprises a stack alternately
  • Another aspect of the invention relates to a fuel cell system comprising fuel cell stacks according to the invention and a vehicle having at least one
  • the vehicle is preferably an electric vehicle, in which an electrical energy generated by the fuel cell system of the supply of an electric traction motor and / or a
  • FIG. 2 shows in a diagram the profiles of the relative humidity of a membrane and in the reaction gas channel along the active region of the bipolar plate in comparison with the minimum moisture content of the membrane
  • FIG. 3 shows a schematic view of the structure according to the invention
  • FIG. 4 shows in a diagram a web-channel ratio of the bipolar plate according to FIG. 3 in relation to the active region
  • FIG. 5 shows in a diagram the profiles of the relative humidity of a membrane and in the reaction gas channel along the active region of the bipolar plate according to FIG. 3 in comparison with the minimum moisture content of the membrane
  • Figure 6 is a schematic sectional view of the structure of a metallic
  • FIG. 7 shows in schematic sectional views A-A and B-B of the bipolar plate according to FIG. 3 the structure of a metallic embodiment
  • FIG. 9 shows a schematic view of the structure according to the invention.
  • FIG. 10 shows in a diagram a web-channel ratio of the bipolar plate according to FIG. 9 in relation to the active region
  • Figure 1 1 is a graph showing the profiles of the relative humidity of a membrane and in the reaction gas channel along the active region of the bipolar plate according to Figure 9 in comparison with the minimum moisture content of the membrane.
  • FIG. 1 shows a bipolar plate 10 according to the prior art.
  • the bipolar plate 10 has two profiled separator plates 12, 14, wherein only one separator plate 12, 14 is visible in the plan view.
  • the separator plates 12, 14 together form an active region 16, on both sides of the manifold areas 18, 20 adjacent, each having two ports 22, 24 for reaction gases and a port 26 for a coolant, over which the active region 16, the reaction gases and the coolant be forwarded and derived from this again.
  • In the bipolar plate 10 separate channels run 28, 30, 32 for the
  • Reaction gases and the coolant which are open groove-like structures, of which only the channels 28 are represented symbolically for a reaction gas by a reinforced line.
  • Figure 1 shows a longitudinal section through one of the channels 28 for a reaction gas, wherein the flow direction 42 is indicated by an arrow. From one side 44 of the channels 28, which, when the bipolar plate 10 is arranged in a fuel cell stack, not shown, adjacent to a gas diffusion layer, penetrates product water 46 of the cell reaction, symbolized by arrows, in this, so that the reaction gas is moistened.
  • the proportion of water (curve 48a) in the reaction gas and the proportion of water (curve 48b) in the membrane of a fuel cell are shown in a diagram in FIG.
  • the reaction gas enters the active region 16 with an insufficient amount of water, that is, the water content is lower than the required minimum moisture content of the membrane. Accordingly, the actual water content of the membrane at the beginning of the active region 16 is too low for optimum reaction of the reaction gases.
  • the reaction gas continuously absorbs product water 46, so that the water content of reaction gas and membrane above the required minimum moisture increase.
  • Figure 3 is an inventively designed bipolar plate 10 for a
  • the construction of the bipolar plate 10 according to the invention corresponds to that of the bipolar plate 10 according to FIG. 1 with the difference according to the invention that the active region 16 is divided into an inlet region 34 in which the reaction gas flows into the active region 16 and into a remaining partial region 36.
  • the channels 28 for a reaction gas have a smaller width B2 than in the partial region 36, while the webs 54 located between the channels 28 have a greater width B1. This is shown in more detail in FIGS. 5 and 7.
  • the entrance area 34 is optically delimited by a vertical line to the partial area 36, which otherwise has no technical significance. This applies correspondingly to the vertical line in FIG. 9.
  • the ratio of the width B1 of the web 54 to the width B2 of the reaction gas channel 28 is shown in a curve 49.
  • this ratio is, for example, 2: 1 (reference numeral 49a), which falls to 1: 1 (reference numeral 49b) with entry into the remaining portion 36 of the active region 16.
  • FIG. 5 shows, as in FIG. 2, the course of the water content in the reaction gas (curve 48a) and in the membrane (curve 48b) of a fuel cell in a diagram and the permissible one Minimum moisture content (curve 48) of the membrane in relation to the length I of the active region 16.
  • a moisture of the membrane is achieved in the inlet region 34, which is above the required minimum moisture, so that an optimized cell reaction can already occur in the inlet area.
  • the humidity increases until the entry region 34 ends and then drops abruptly to the required minimum moisture content.
  • An extension of the inlet region 34 would result in a further increase in the humidity, but would have a negative effect that the passage of the reaction gas to / through the narrow channels 28 would be hindered.
  • FIGS. 6 and 7 show a bipolar plate 10 according to FIG. 3 in sectional views AA and BB, with the sections AA in the inlet region 34 and the sections BB in the remaining partial region 36 of the active region 16.
  • the open, channel-like reaction gas channels 28, 32 adjoin to a GDL 50 in which a membrane 52 is located.
  • section A-A has a width B1 for the passage 30 through the channel
  • FIG. 8 shows simulation results of the local current-voltage characteristic assuming different channel geometries, ie narrow compared to wide webs 54 or correspondingly narrow or wide channels 28 and with differently set relative humidities in the reaction gas channel 28 (60% vs. 100%).
  • the curves show 100% relative humidity for wide lands 54 (56a), 100% for narrow lands 54 (58a), 60% for wide lands 54 (56b), 60% for narrow lands 54 (58b).
  • the results show that at high humidity narrow webs 54 are advantageous (dashed lines), but at low humidity wide webs 54 can lead to higher power (solid lines). Therefore, the embodiment according to the invention of the active region 16 with wide webs 54 in the entry region 34 and with narrower webs 54 in the remaining subregion 36 of the active region 16 is advantageous.
  • FIG. 9 shows a bipolar plate 10 designed according to the invention after a second one
  • the entry region 34 is designed in such a way that the width B2 of the channel 28 increases continuously from the beginning of the entry region 34 to the remaining subregion 36 and then retains its width B2.
  • the ratio of the width B1 of the web 54 to the width B2 of the reaction gas channel 28 is shown in a curve 49. In the inlet region 34, this ratio is for example 2: 1 and falls continuously (reference numeral 49a) until it enters the remaining portion 36 of the active region 16 to 1: 1 (reference numeral 49b).
  • Figure 1 1 shows the course of the water content in the reaction gas 48a and in the membrane 48b of a fuel cell in a diagram and the minimum permissible moisture of the membrane 48 in relation to the length I of the active region 16.
  • the inlet region 34 is characterized by the
  • inventive design achieves a humidity of the membrane, which over the

Abstract

In order to provide a bipolar plate (10) for a fuel cell having two profiled separator plates (12, 14) designed in such a way that the bipolar plate (10) has separate channels (28, 30, 32) for the reaction gases and the coolant, wherein the gas composition is incorporated in the active region, according to the invention, the channels (28, 32) for a reaction gas or both reaction gases have a smaller width (B2) in an inlet region (34) of the active region (16) than in the remaining sub-region (36) of the active region (16), wherein the width (B2) thereof continuously increases from the beginning to the end of the inlet region (34), while supports (54) between the channels (28, 32) have a greater width (B1) than in the remaining sub-region (36) of the active region (16), wherein the sum of the width (B2) of the channels and the width (B1) of the supports (54) is constant, and the width (B2, B2) of the channels (28, 32) and the supports (54) is constant in the entire remaining sub-region (36). The invention also relates to a fuel cell stack, a fuel cell system and a vehicle.

Description

Beschreibung  description
Bipolarplatte mit variabler Breite der Reaktionsgaskanäle im Eintrittsbereich des aktiven Bipolar plate with variable width of the reaction gas channels in the inlet region of the active
Bereichs, Brennstoffzellenstapel und Brennstoffzellensystem  Area, fuel cell stack and fuel cell system
mit solchen Bipolarplatten sowie Fahrzeug  with such bipolar plates as well as vehicle
Die Erfindung betrifft eine Bipolarplatte für eine Brennstoffzelle, die zwei profilierte The invention relates to a bipolar plate for a fuel cell, the two profiled
Separatorplatten besitzt, jeweils aufweisend einen aktiven Bereich sowie zwei Verteilerbereiche zur Zu- und Ableitung von Reaktionsgasen und Kühlmitteln zu beziehungsweise aus dem aktiven Bereich, wobei die Separatorplatten derart ausgebildet sind, dass die Bipolarplatte separate Kanäle für die Reaktionsgase und das Kühlmittel aufweist, welche Ports für Separator plates has, each having an active area and two manifold areas for supply and discharge of reaction gases and coolants to or from the active area, the separator plates are formed such that the bipolar plate has separate channels for the reaction gases and the coolant, which ports for
Reaktionsgase und Kühlmittel beider Verteilerbereiche miteinander verbinden und die jeweils als offene rinnenartige Kanalstrukturen ausgebildet sind, wobei die zwei profilierten Reaction gases and coolant both distribution areas connect together and each formed as an open channel-like channel structures, the two profiled
Separatorplatten derart übereinander angeordnet sind, dass in den aneinander grenzenden Seiten durch die Kanalstrukturen Kühlmittelkanäle ausgeformt sind, einen Separator plates are arranged one above the other, that in the adjacent sides through the channel structures coolant channels are formed, a
Brennstoffzellenstapel, ein Brennstoffzellensystem und ein Fahrzeug. Fuel cell stack, a fuel cell system and a vehicle.
Brennstoffzellen nutzen die chemische Umsetzung eines Brennstoffs mit Sauerstoff zu Wasser, um elektrische Energie zu erzeugen. Hierfür enthalten Brennstoffzellen als Kernkomponente die sogenannte Membran-Elektroden-Einheit (MEA für membrane electrode assembly), die ein Verbund aus einer ionenleitenden, insbesondere protonenleitenden Membran und jeweils einer beidseitig an der Membran angeordneten Elektrode (Anode und Kathode) ist. Zudem können Gasdiffusionsschichten (GDL) beidseitig der Membran-Elektroden-Einheit an den der Membran abgewandten Seiten der Elektroden angeordnet sein. In der Regel wird die Brennstoffzelle durch eine Vielzahl, im Stapel (stack) angeordneter MEAs gebildet, deren elektrische Leistungen sich addieren. Im Betrieb der Brennstoffzelle wird der Brennstoff, insbesondere Wasserstoff H2 oder ein wasserstoffhaltiges Gasgemisch, der Anode zugeführt, wo eine elektrochemische Oxidation von H2 zu H+ unter Abgabe von Elektronen stattfindet. Über den Elektrolyten oder die Membran, welche die Reaktionsräume gasdicht voneinander trennt und elektrisch isoliert, erfolgt ein (wassergebundener oder wasserfreier) Transport der Protonen H+ aus dem Anodenraum in den Kathodenraum. Die an der Anode bereitgestellten Elektronen werden über eine elektrische Leitung der Kathode zugeleitet. Der Kathode wird Sauerstoff oder ein sauerstoffhaltiges Gasgemisch zugeführt, sodass eine Reduktion von 02 zu O2" unter Aufnahme der Elektronen stattfindet. Gleichzeitig reagieren im Kathodenraum diese Sauerstoffanionen mit den über die Membran transportierten Protonen unter Bildung von Wasser. Fuel cells use the chemical transformation of a fuel with oxygen to water to generate electrical energy. For this purpose, fuel cells contain as core component the so-called membrane electrode assembly (MEA for membrane electrode assembly), which is a composite of an ion-conducting, in particular proton-conducting membrane and in each case an electrode arranged on both sides of the membrane (anode and cathode). In addition, gas diffusion layers (GDL) can be arranged on both sides of the membrane-electrode assembly on the sides of the electrodes facing away from the membrane. As a rule, the fuel cell is formed by a multiplicity of stacked MEAs whose electrical powers add up. During operation of the fuel cell, the fuel, in particular hydrogen H 2 or a hydrogen-containing gas mixture, is fed to the anode, where an electrochemical oxidation of H 2 to H + takes place with emission of electrons. Via the electrolyte or the membrane, which separates the reaction spaces gas-tight from each other and electrically isolated, takes place (water-bound or anhydrous) transport of protons H + from the anode compartment in the cathode compartment. The electrons provided at the anode are supplied to the cathode via an electrical line. The cathode is supplied with oxygen or an oxygen-containing gas mixture, so that a reduction of 0 2 to O 2 " taking the Electrons take place. At the same time, these oxygen anions in the cathode compartment react with the protons transported via the membrane to form water.
Die Brennstoffzelle wird durch eine Vielzahl, im Stapel angeordneter Membran-Elektroden- Einheiten gebildet, sodass auch von einem Brennstoffzellenstapel gesprochen wird. Zwischen zwei Membran-Elektroden-Einheiten ist jeweils eine Bipolarplatte angeordnet, welche eine Versorgung der Einzelzellen mit den Betriebsmedien, also den Reaktanden und einer The fuel cell is formed by a plurality of membrane-electrode units arranged in the stack, so that it is also referred to as a fuel cell stack. Between two membrane-electrode units, a bipolar plate is in each case arranged, which is a supply of the individual cells with the operating media, ie the reactants and a
Kühlflüssigkeit, sicherstellt. Zudem sorgen die Bipolarplatten für einen elektrisch leitfähigen Kontakt zu den Membran-Elektroden-Einheiten. Des Weiteren gewährleisten sie eine dichte Trennung zwischen Anoden- und Kathodenraum. Coolant, ensures. In addition, the bipolar plates provide an electrically conductive contact to the membrane-electrode assemblies. Furthermore, they ensure a tight separation between anode and cathode space.
Die Bipolarplatten sind zumeist aus zwei profilierten elektrisch leitfähigen Separatorplatten aufgebaut, welche eine Struktur in Form eines beiderseits der Platten angeordneten The bipolar plates are usually constructed of two profiled electrically conductive Separatorplatten, which arranged a structure in the form of either side of the plates
Höhenprofils aufweisen. Durch dieses Profil ergeben sich beiderseits der Platten mehr oder weniger diskrete Kanäle, die ausgebildet sind, die Betriebsmedien zu führen. Die Have height profiles. This profile results in more or less discrete channels on both sides of the plates, which are designed to guide the operating media. The
Betriebsmedien sind wiederum durch die Platten voneinander getrennt, sodass im Inneren der Platte das Kühlmittel geführt wird, während außerhalb die Reaktandengase geführt werden. Die Kanäle der Reaktandengase sind zum einen von der jeweiligen Platte und zum anderen von einer Gasdiffusionsschicht begrenzt. Operating media are in turn separated by the plates so that inside the plate the coolant is passed while outside the reactant gases are conducted. The channels of the reactant gases are limited on the one hand by the respective plate and on the other by a gas diffusion layer.
Zur Steuerung des Wasserhaushaltes hinsichtlich der Reaktionsgase in den Bipolarplatten zur Erhöhung von Leistungsdichte, Wirkungsgrad und Lebensdauer der Brennstoffzelle ist unter anderem in der WO 2012/143781 A1 und US 20090197134 A1 vorgeschlagen worden, in den Kanal für das zu befeuchtende Reaktionsgas eine Vielzahl von Metallstreifen aus Titan einzubringen, was jedoch teuer und auch aufwendig in der Herstellung ist, da diese schwer zu fixieren und zu positionieren sind, beziehungsweise eine gelochte Metallplatte in den Kanal einzubringen, was ebenfalls teuer und aufwendig in der Herstellung ist. Zudem lassen sich diese Lösungen nicht in Kombination mit graphitischen Bipolarplatten anwenden. To control the water balance with respect to the reaction gases in the bipolar plates to increase the power density, efficiency and life of the fuel cell has been proposed, inter alia, in WO 2012/143781 A1 and US 20090197134 A1, in the channel for the reaction gas to be humidified, a plurality of metal strips To bring in titanium, which is expensive and expensive to manufacture, since they are difficult to fix and position, or to bring a perforated metal plate in the channel, which is also expensive and expensive to manufacture. In addition, these solutions can not be used in combination with graphitic bipolar plates.
Weiterhin ist aus der DE 10 2008 033 21 1 A1 eine Bipolarplatte bekannt, bei der die Breite der Kanäle eines Reaktionsgases und der dazwischen liegenden Stege kontinuierlich variiert wird. Furthermore, a bipolar plate is known from DE 10 2008 033 21 1 A1, in which the width of the channels of a reaction gas and the webs lying therebetween is continuously varied.
Der Erfindung liegt nun die Aufgabe zugrunde, eine Bipolarplatte und einen The invention is based on the object, a bipolar plate and a
Brennstoffzellenstapel bereitzustellen, bei denen die Gaszusammensetzung und Massenströme in den Reaktionsgaskanälen in Relation zur Länge des aktiven Bereichs berücksichtigt werden. Erfindungsgemäß wird eine Bipolarplatte für eine Brennstoffzelle bereitgestellt, die zwei profilierte Separatorplatten besitzt, jeweils aufweisend einen aktiven Bereich sowie zwei Verteilerbereiche zur Zu- und Ableitung von Reaktionsgasen und Kühlmitteln zu To provide fuel cell stacks that take into account the gas composition and mass flows in the reaction gas channels in relation to the length of the active region. According to the invention, a bipolar plate for a fuel cell is provided, which has two profiled separator plates, each having an active region and two distributor regions for the supply and discharge of reaction gases and coolants
beziehungsweise aus dem aktiven Bereich, wobei die Separatorplatten derart ausgebildet sind, dass die Bipolarplatte separate Kanäle für die Reaktionsgase und das Kühlmittel aufweist, welche Ports für Reaktionsgase und Kühlmittel beider Verteilerbereiche miteinander verbinden und die jeweils als offene rinnenartige Kanalstrukturen ausgebildet sind. Die zwei profilierten Separatorplatten sind derart übereinander angeordnet, dass in den aneinandergrenzenden Seiten durch die Kanalstrukturen Kühlmittelkanäle ausgeformt sind. Die erfindungsgemäße Bipolarplatte zeichnet sich durch folgende Ausbildungen der Kanalstrukturen aus: or from the active region, wherein the separator plates are formed such that the bipolar plate has separate channels for the reaction gases and the coolant, which connect ports for reaction gases and coolant both distribution areas and which are each designed as open channel-like channel structures. The two profiled separator plates are arranged one above the other such that coolant channels are formed in the adjoining sides through the channel structures. The bipolar plate according to the invention is characterized by the following configurations of the channel structures:
- Die Kanäle für ein Reaktionsgas oder beide Reaktionsgase weisen in einem Eintrittsbereich des aktiven Bereichs eine geringere Breite auf als im restlichen Teilbereich des aktiven Bereichs, wobei die Breite der Kanäle vom Anfang bis Ende des Eintrittsbereichs kontinuierlich zunimmt.  The channels for a reaction gas or both reaction gases have a smaller width in an inlet region of the active region than in the remaining partial region of the active region, the width of the channels increasing continuously from the beginning to the end of the inlet region.
- Zwischen den Kanälen befindliche Stege weisen in dem Eintrittsbereich eine größere Breite auf als im restlichen Teilbereich des aktiven Bereichs.  - Webs located between the channels have a greater width in the inlet region than in the remaining partial region of the active region.
- Die Summe der Breite der Kanäle und der Breite der Stege ist konstant.  - The sum of the width of the channels and the width of the webs is constant.
- Die Breite der Kanäle und die Breite der Stege sind im gesamten restlichen Teilbereich konstant.  - The width of the channels and the width of the webs are constant throughout the remaining portion.
Die Summe aus Kanalbreite und Stegbreite stellt eine Kanal-Steg-Einheit dar und wird auch als „Channel pitch" bezeichnet. The sum of channel width and land width represents a channel land unit and is also referred to as a "channel pitch".
Durch die erfindungsgemäße Ausgestaltung einer Bipolarplatte findet bei Verwendung derselben in einem Brennstoffzellenstapel im Eintrittsbereich des oder der Reaktionsgase eine erhöhte Befeuchtung der Membran statt, vorteilhafterweise selbst bei geringer Eintrittsfeuchte des Kathodengases. The inventive design of a bipolar plate, when used in a fuel cell stack in the inlet region of the reaction gases or an increased humidification of the membrane takes place, advantageously even at low inlet moisture of the cathode gas.
Um diese optimierte Befeuchtung zu erreichen, wird die Breite der Reaktionsgaskanäle im Bereich des Gaseintritts in den aktiven Bereich herabgesetzt, als es im sonstigen aktiven Bereich vorgesehen ist und somit die Breite der Stege zwischen den Reaktionsgaskanälen heraufgesetzt, sodass die Reaktionsgase und auch das Produktwasser in geringerem Ausmaß durch die GDL diffundieren, und sich somit eine höhere Feuchtedifferenz zwischen Membran und Reaktionsgaskanälen einstellt. Nach einer bevorzugten Ausführungsform nimmt der Eintrittsbereich 5 bis 30 %, vorzugsweise 10 bis 25 % und besonders bevorzugt 20% des aktiven Bereichs ein, sodass die Membran bereits am Anfang des aktiven Bereichs ausreichend befeuchtet ist und gleichzeitig eine zu starke Befeuchtung im weiteren Verlauf des aktiven Bereichs vermieden wird. In order to achieve this optimized humidification, the width of the reaction gas channels in the region of the gas inlet is reduced in the active area, as it is provided in the other active area and thus increased the width of the webs between the reaction gas channels, so that the reaction gases and the product water in less Extent through the GDL diffuse, and thus sets a higher humidity difference between the membrane and reaction gas channels. According to a preferred embodiment, the inlet region occupies 5 to 30%, preferably 10 to 25% and particularly preferably 20% of the active region, so that the membrane is already sufficiently moistened at the beginning of the active region and at the same time an excessive moistening in the further course of the active Area is avoided.
Um die Befeuchtung auf das jeweilige Brennstoffzellensystem optimal abstimmen zu können kann die Breite der Kanäle beziehungsweise der Stege vom Anfang bis Ende des In order to be able to optimally tune the humidification to the respective fuel cell system, the width of the channels or of the webs can be adjusted from the beginning to the end of the
Eintrittsbereichs kontinuierlich oder diskontinuierlich zunehmend ausgestaltet sein. Entry area continuously or discontinuously be designed increasingly.
Unter diskontinuierlich ist zu verstehen, dass die Kanalbreite im Eintrittsbereich geringer als im restlichen aktiven Bereich ist, jedoch konstant, und dass die Kanäle sich erst beim Eintritt in den restlichen Bereich des aktiven Bereichs verbreitern. Um Turbulenzen des oder der By discontinuous, it is to be understood that the channel width in the entry region is smaller than in the remaining active region, but constant, and that the channels widen only upon entry into the remaining region of the active region. To turbulence of or
Reaktionsgase an dieser Stelle zu vermeiden, kann ein kurzer Übergangsbereich vorgesehen sein, der eine Stufe in den Kanälen vermeidet. To avoid reaction gases at this point, a short transition region can be provided, which avoids a step in the channels.
Die erfindungsgemäße Ausgestaltung einer Bipolarplatte lässt sich vorteilhafterweise bei metallischen oder graphitischen Bipolarplatten umsetzen. The inventive design of a bipolar plate can be implemented advantageously in metallic or graphitic bipolar plates.
Die Erfindung lässt sich vorzugsweise zur Steuerung der Befeuchtung des Kathodengases einsetzen, es ist jedoch auch für die Steuerung der Feuchtigkeit des Anodengases geeignet. Ebenso können auch beide Reaktionsgase gleichzeitig durch eine erfindungsgemäße The invention can be preferably used to control the humidification of the cathode gas, but it is also suitable for the control of the humidity of the anode gas. Likewise, both reaction gases can simultaneously by a
Ausgestaltung des Eintrittsbereichs der Bipolarplatte hinsichtlich der Befeuchtung beeinflusst werden. Embodiment of the inlet region of the bipolar plate with respect to the humidification can be influenced.
Weitere bevorzugte Ausgestaltungen der Erfindung ergeben sich aus den übrigen, in den Unteransprüchen genannten Merkmalen. Further preferred embodiments of the invention will become apparent from the remaining, mentioned in the dependent claims characteristics.
Die verschiedenen in dieser Anmeldung genannten Ausführungsformen der Erfindung sind, sofern im Einzelfall nicht anders ausgeführt, mit Vorteil miteinander kombinierbar. The various embodiments of the invention mentioned in this application are, unless otherwise stated in the individual case, advantageously combinable with each other.
Durch die erfindungsgemäße Ausgestaltung einer Bipolarplatte beziehungsweise der Anoden- und Kathodenplatte einer Bipolarplatte werden Druckverteilung, Feuchteverteilung und The inventive design of a bipolar plate or the anode and cathode plate of a bipolar plate pressure distribution, moisture distribution and
Geschwindigkeitsverteilung in den Anoden- und Kathodengaskanälen im aktiven Bereich der Bipolarplatte optimiert. Optimierung bedeutet in diesem Kontext, dass möglichst über den gesamten aktiven Bereich einheitliche Druckverhältnisse, gleichmäßige Befeuchtung der Reaktanten sowie der Membran sowie gleiche Strömungsgeschwindigkeiten vorliegen. Zudem werden vorteilhafterweise damit Leistung und Lebensdauer des Brennstoffzellenstapels erhöht. Velocity distribution in the anode and cathode gas channels optimized in the active region of the bipolar plate. Optimization in this context means that as far as possible over the entire active area uniform pressure conditions, uniform humidification of Reactants and the membrane and same flow rates are present. In addition, the performance and service life of the fuel cell stack are advantageously increased thereby.
Der Brennstoffzellenstapel gemäß der Erfindung umfasst einen Stapel abwechselnd The fuel cell stack according to the invention comprises a stack alternately
angeordneter Membran-Elektroden-Einheiten und Bipolarplatten, die wie voranstehend beschrieben, ausgestaltet sind. arranged membrane electrode assemblies and bipolar plates, which are configured as described above.
Ein weiterer Aspekt der Erfindung betrifft ein Brennstoffzellensystem erfindungsgemäße Brennstoffzellenstapel aufweisend sowie ein Fahrzeug, das zumindest einen Another aspect of the invention relates to a fuel cell system comprising fuel cell stacks according to the invention and a vehicle having at least one
erfindungsgemäßen Brennstoffzellenstapel aufweist. Bei dem Fahrzeug handelt es sich vorzugsweise um ein Elektrofahrzeug, bei dem eine von dem Brennstoffzellensystem erzeugte elektrische Energie der Versorgung eines Elektrotraktionsmotors und/oder einer Having inventive fuel cell stack. The vehicle is preferably an electric vehicle, in which an electrical energy generated by the fuel cell system of the supply of an electric traction motor and / or a
Traktionsbatterie dient. Traction battery is used.
Die Erfindung wird nachfolgend in Ausführungsbeispielen anhand der zugehörigen The invention is described below in embodiments with reference to the associated
Zeichnungen erläutert. Es zeigen: Drawings explained. Show it:
Figur 1 in schematischen Ansichten den Aufbau einer Bipolarplatte nach dem Stand der Technik, 1 shows in schematic views the structure of a bipolar plate according to the prior art,
Figur 2 in einem Diagramm die Verläufe der relativen Feuchte einer Membran und im Reaktionsgaskanal entlang des aktiven Bereichs der Bipolarplatte im Vergleich mit der Mindestfeuchte der Membran, FIG. 2 shows in a diagram the profiles of the relative humidity of a membrane and in the reaction gas channel along the active region of the bipolar plate in comparison with the minimum moisture content of the membrane,
Figur 3 in einer schematischen Ansicht den erfindungsgemäßen Aufbau einer FIG. 3 shows a schematic view of the structure according to the invention
Bipolarplatte,  bipolar,
Figur 4 in einem Diagramm ein Steg-Kanal-Verhältnis der Bipolarplatte nach Figur 3 in Relation zum aktiven Bereich, FIG. 4 shows in a diagram a web-channel ratio of the bipolar plate according to FIG. 3 in relation to the active region,
Figur 5 in einem Diagramm die Verläufe der relativen Feuchte einer Membran und im Reaktionsgaskanal entlang des aktiven Bereichs der Bipolarplatte nach Figur 3 im Vergleich mit der Mindestfeuchte der Membran, Figur 6 in einer schematischen geschnittenen Ansicht den Aufbau einer metallischenFIG. 5 shows in a diagram the profiles of the relative humidity of a membrane and in the reaction gas channel along the active region of the bipolar plate according to FIG. 3 in comparison with the minimum moisture content of the membrane, Figure 6 is a schematic sectional view of the structure of a metallic
Bipolarplatte nach dem Stand der Technik oder einer erfindungsgemäßen Bipolarplatte im ungeteilten Bereich des Kanals für ein Reaktionsgas, Bipolar plate according to the prior art or a bipolar plate according to the invention in the undivided region of the channel for a reaction gas,
Figur 7 in schematischen geschnittenen Ansichten A-A und B-B der Bipolarplatte nach Figur 3 den Aufbau einer metallischen Ausführungsform, 7 shows in schematic sectional views A-A and B-B of the bipolar plate according to FIG. 3 the structure of a metallic embodiment, FIG.
Figur 8 in einem Diagramm Strom-Spannungskennlinien für verschiedene Figure 8 in a diagram current-voltage characteristics for various
Kanalgeometrien,  Channel geometries,
Figur 9 in einer schematischen Ansicht den erfindungsgemäßen Aufbau einer FIG. 9 shows a schematic view of the structure according to the invention
Bipolarplatte nach einer zweiten Ausführungsform,  Bipolar plate according to a second embodiment,
Figur 10 in einem Diagramm ein Steg-Kanal-Verhältnis der Bipolarplatte nach Figur 9 in Relation zum aktiven Bereich, und FIG. 10 shows in a diagram a web-channel ratio of the bipolar plate according to FIG. 9 in relation to the active region, and FIG
Figur 1 1 in einem Diagramm die Verläufe der relativen Feuchte einer Membran und im Reaktionsgaskanal entlang des aktiven Bereichs der Bipolarplatte nach Figur 9 im Vergleich mit der Mindestfeuchte der Membran. Figure 1 1 is a graph showing the profiles of the relative humidity of a membrane and in the reaction gas channel along the active region of the bipolar plate according to Figure 9 in comparison with the minimum moisture content of the membrane.
In Figur 1 ist eine Bipolarplatte 10 nach dem Stand der Technik dargestellt. FIG. 1 shows a bipolar plate 10 according to the prior art.
Die Bipolarplatte 10 weist zwei profilierte Separatorplatten 12, 14 auf, wobei in der Aufsicht nur eine Separatorplatte 12, 14 sichtbar ist. Die Separatorplatten 12, 14 bilden gemeinsam einen aktiven Bereich 16 aus, an den beidseitig Verteilerbereiche 18, 20 angrenzen, die jeweils zwei Ports 22, 24 für Reaktionsgase und einen Port 26 für ein Kühlmittel aufweisen, worüber dem aktiven Bereich 16 die Reaktionsgase und das Kühlmittel zugeleitet und aus diesem wieder abgeleitet werden. In der Bipolarplatte 10 verlaufen separate Kanäle 28, 30, 32 für die The bipolar plate 10 has two profiled separator plates 12, 14, wherein only one separator plate 12, 14 is visible in the plan view. The separator plates 12, 14 together form an active region 16, on both sides of the manifold areas 18, 20 adjacent, each having two ports 22, 24 for reaction gases and a port 26 for a coolant, over which the active region 16, the reaction gases and the coolant be forwarded and derived from this again. In the bipolar plate 10 separate channels run 28, 30, 32 for the
Reaktionsgase und das Kühlmittel, die offene rinnenartige Strukturen sind, von denen lediglich die Kanäle 28 für ein Reaktionsgas durch eine verstärkte Linie symbolhaft dargestellt sind. Reaction gases and the coolant, which are open groove-like structures, of which only the channels 28 are represented symbolically for a reaction gas by a reinforced line.
Zudem zeigt Figur 1 einen Längsschnitt durch einen der Kanäle 28 für ein Reaktionsgas, wobei die Strömungsrichtung 42 durch einen Pfeil angegeben wird. Von einer Seite 44 der Kanäle 28, die, wenn die Bipolarplatte 10 in einem nicht dargestellten Brennstoffzellenstapel angeordnet ist, an eine Gasdiffusionsschicht grenzt, dringt Produktwasser 46 der Zellreaktion, durch Pfeile symbolisiert, in diesen ein, sodass das Reaktionsgas befeuchtet wird. Der Wasseranteil (Kurve 48a) im Reaktionsgas und der Wasseranteil (Kurve 48b) in der Membran einer Brennstoffzelle werden in einem Diagramm in Figur 2 der erlaubten In addition, Figure 1 shows a longitudinal section through one of the channels 28 for a reaction gas, wherein the flow direction 42 is indicated by an arrow. From one side 44 of the channels 28, which, when the bipolar plate 10 is arranged in a fuel cell stack, not shown, adjacent to a gas diffusion layer, penetrates product water 46 of the cell reaction, symbolized by arrows, in this, so that the reaction gas is moistened. The proportion of water (curve 48a) in the reaction gas and the proportion of water (curve 48b) in the membrane of a fuel cell are shown in a diagram in FIG
Mindestfeuchte (Kurve 48) der Membran in Relation zur Länge I des aktiven Bereichs 16 gegenübergestellt. Minimum moisture (curve 48) of the membrane in relation to the length I of the active region 16 compared.
Aus diesem Diagramm ist ersichtlich, dass bei Brennstoffzellen mit Bipolarplatten 10 nach dem Stand der Technik das Reaktionsgas mit einem zu geringen Wasseranteil in den aktiven Bereich 16 eintritt, das heißt, der Wassergehalt ist niedriger als die erforderliche Mindestfeuchte der Membran. Dementsprechend ist der tatsächliche Wassergehalt der Membran am Anfang des aktiven Bereichs 16 zu gering für eine optimale Umsetzung der Reaktionsgase. Im Verlauf des Durchströmens des aktiven Bereichs 16 nimmt das Reaktionsgas ständig Produktwasser 46 auf, sodass der Wassergehalt von Reaktionsgas und Membran über die erforderliche Mindestfeuchte ansteigen. From this diagram, it can be seen that in fuel cells with bipolar plates 10 according to the prior art, the reaction gas enters the active region 16 with an insufficient amount of water, that is, the water content is lower than the required minimum moisture content of the membrane. Accordingly, the actual water content of the membrane at the beginning of the active region 16 is too low for optimum reaction of the reaction gases. In the course of flowing through the active region 16, the reaction gas continuously absorbs product water 46, so that the water content of reaction gas and membrane above the required minimum moisture increase.
In Figur 3 ist eine erfindungsgemäß ausgestaltete Bipolarplatte 10 für einen In Figure 3 is an inventively designed bipolar plate 10 for a
erfindungsgemäßen, hier nicht dargestellten, Brennstoffzellenstapel gezeigt. Der Aufbau der erfindungsgemäßen Bipolarplatte 10 entspricht dem der Bipolarplatte 10 nach Figur 1 mit dem erfindungsgemäßen Unterschied, dass der aktive Bereich 16 in einen Eintrittsbereich 34, in dem das Reaktionsgas in den aktiven Bereich 16 einströmt, und in einen verbleibenden Teilbereich 36 gegliedert ist. Im Eintrittsbereich 34 weisen die Kanäle 28 für ein Reaktionsgas eine geringere Breite B2 auf als im Teilbereich 36, während die zwischen den Kanälen 28 befindlichen Stege 54 eine größere Breite B1 aufweisen. Dies wird in den Figuren 5 und 7 näher dargestellt. according to the invention, not shown here, shown fuel cell stack. The construction of the bipolar plate 10 according to the invention corresponds to that of the bipolar plate 10 according to FIG. 1 with the difference according to the invention that the active region 16 is divided into an inlet region 34 in which the reaction gas flows into the active region 16 and into a remaining partial region 36. In the inlet region 34, the channels 28 for a reaction gas have a smaller width B2 than in the partial region 36, while the webs 54 located between the channels 28 have a greater width B1. This is shown in more detail in FIGS. 5 and 7.
Der Eintrittsbereich 34 ist durch eine vertikale Linie zum Teilbereich 36 optisch abgegrenzt, die ansonsten keine technische Bedeutung besitzt. Dies gilt entsprechend für die vertikale Linie in Figur 9. The entrance area 34 is optically delimited by a vertical line to the partial area 36, which otherwise has no technical significance. This applies correspondingly to the vertical line in FIG. 9.
Im Diagramm gemäß Figur 4 wird in einer Kurve 49 das Verhältnis der Breite B1 des Steges 54 zur Breite B2 des Reaktionsgaskanals 28 dargestellt. Im Eintrittsbereich 34 beträgt dieses Verhältnis beispielsweise 2:1 (Bezugszeichen 49a), das mit Eintritt in den verbleibenden Teilbereich 36 des aktiven Bereichs 16 auf 1 :1 (Bezugszeichen 49b) fällt. In the diagram according to FIG. 4, the ratio of the width B1 of the web 54 to the width B2 of the reaction gas channel 28 is shown in a curve 49. In the entrance region 34, this ratio is, for example, 2: 1 (reference numeral 49a), which falls to 1: 1 (reference numeral 49b) with entry into the remaining portion 36 of the active region 16.
Figur 5 zeigt, wie Figur 2, den Verlauf des Wasseranteils im Reaktionsgas (Kurve 48a) und in der Membran (Kurve 48b) einer Brennstoffzelle in einem Diagramm sowie die erlaubte Mindestfeuchte (Kurve 48) der Membran in Relation zur Länge I des aktiven Bereichs 16. Im Eintrittsbereich 34 wird durch die erfindungsgemäße Ausgestaltung eine Feuchte der Membran erreicht, die über der erforderlichen Mindestfeuchte liegt, sodass bereits im Eintrittsbereich eine optimierte Zellreaktion ablaufen kann. Die Feuchte steigt solange an, bis der Eintrittsbereich 34 endet und sinkt dann abrupt bis zur erforderlichen Mindestfeuchte ab. Eine Verlängerung des Eintrittsbereichs 34 hätte einen weiteren Anstieg der Feuchtigkeit zur Folge, wobei jedoch negativ zum Tragen kommen würde, dass der Durchtritt des Reaktionsgases zu den/durch die schmalen Kanäle 28 behindert würde. FIG. 5 shows, as in FIG. 2, the course of the water content in the reaction gas (curve 48a) and in the membrane (curve 48b) of a fuel cell in a diagram and the permissible one Minimum moisture content (curve 48) of the membrane in relation to the length I of the active region 16. In the inlet region 34, a moisture of the membrane is achieved in the inlet region 34, which is above the required minimum moisture, so that an optimized cell reaction can already occur in the inlet area. The humidity increases until the entry region 34 ends and then drops abruptly to the required minimum moisture content. An extension of the inlet region 34 would result in a further increase in the humidity, but would have a negative effect that the passage of the reaction gas to / through the narrow channels 28 would be hindered.
Figuren 6 und 7 zeigen eine Bipolarplatte 10 gemäß Figur 3 in Schnittansichten A-A und B-B, wobei die Schnitte A-A im Eintrittsbereich 34 liegen und die Schnitte B-B im verbleibenden Teilbereich 36 des aktiven Bereichs 16. In diesen Darstellungen grenzen die offenen, rinnenartigen Reaktionsgaskanäle 28, 32 an eine GDL 50, in der eine Membran 52 befindlich ist. Zudem ist in Figur 7, Schnitt A-A eine Breite B1 für den durch den Kanal 30 für das FIGS. 6 and 7 show a bipolar plate 10 according to FIG. 3 in sectional views AA and BB, with the sections AA in the inlet region 34 and the sections BB in the remaining partial region 36 of the active region 16. In these illustrations, the open, channel-like reaction gas channels 28, 32 adjoin to a GDL 50 in which a membrane 52 is located. In addition, in FIG. 7, section A-A has a width B1 for the passage 30 through the channel
Kühlmittel ausgebildeten Steg 54 und eine Breite B2 für den Reaktionsgaskanal 28, die zusammen die Breite B3 für eine Kanal-Steg-Einheit ergeben, eingezeichnet. Coolant formed web 54 and a width B2 for the reaction gas channel 28, which together give the width B3 for a channel-web unit drawn.
Figur 8 zeigt Simulationsergebnisse der lokalen Strom-Spannungs-Kennlinie bei Annahme verschiedener Kanalgeometrien, das heißt schmale im Vergleich zu breiten Stegen 54 beziehungsweise entsprechend schmale oder breite Kanäle 28 und bei unterschiedlich eingestellten relativen Feuchten im Reaktionsgaskanal 28 (60% vs. 100%). Die Kurven zeigen 100% relative Feuchte für breite Stege 54 (56a), 100% für schmale Stege 54 (58a), 60% für breite Stege 54 (56b), 60% für schmale Stege 54 (58b). Die Ergebnisse zeigen, dass bei hoher Feuchte zwar schmale Stege 54 vorteilhaft sind (gestrichelte Linien), bei geringer Feuchte jedoch breite Stege 54 zu höherer Leistung führen können (durchgezogene Linien). Daher ist die erfindungsgemäße Ausgestaltung des aktiven Bereichs 16 mit breiten Stegen 54 im Eintrittsbereich 34 und mit schmaleren Stegen 54 im restlichen Teilbereich 36 des aktiven Bereichs 16 von Vorteil. FIG. 8 shows simulation results of the local current-voltage characteristic assuming different channel geometries, ie narrow compared to wide webs 54 or correspondingly narrow or wide channels 28 and with differently set relative humidities in the reaction gas channel 28 (60% vs. 100%). The curves show 100% relative humidity for wide lands 54 (56a), 100% for narrow lands 54 (58a), 60% for wide lands 54 (56b), 60% for narrow lands 54 (58b). The results show that at high humidity narrow webs 54 are advantageous (dashed lines), but at low humidity wide webs 54 can lead to higher power (solid lines). Therefore, the embodiment according to the invention of the active region 16 with wide webs 54 in the entry region 34 and with narrower webs 54 in the remaining subregion 36 of the active region 16 is advantageous.
In Figur 9 ist eine erfindungsgemäß ausgestaltete Bipolarplatte 10 nach einer zweiten FIG. 9 shows a bipolar plate 10 designed according to the invention after a second one
Ausführungsform dargestellt. Im Unterschied zur Ausführungsform nach Figur 3 ist der Eintrittsbereich 34 derart ausgestaltet, dass die Breite B2 des Kanals 28 vom Anfang des Eintrittsbereichs 34 bis zum restlichen Teilbereich 36 kontinuierlich zunimmt und dann seine Breite B2 behält. Im Diagramm gemäß Figur 10 wird in einer Kurve 49 das Verhältnis der Breite B1 des Steges 54 zur Breite B2 des Reaktionsgaskanals 28 dargestellt. Im Eintrittsbereich 34 beträgt dieses Verhältnis beispielsweise 2:1 und fällt kontinuierlich (Bezugszeichen 49a) bis zum Eintritt in den verbleibenden Teilbereich 36 des aktiven Bereichs 16 auf 1 :1 (Bezugszeichen 49b). Embodiment shown. In contrast to the embodiment according to FIG. 3, the entry region 34 is designed in such a way that the width B2 of the channel 28 increases continuously from the beginning of the entry region 34 to the remaining subregion 36 and then retains its width B2. In the diagram according to FIG. 10, the ratio of the width B1 of the web 54 to the width B2 of the reaction gas channel 28 is shown in a curve 49. In the inlet region 34, this ratio is for example 2: 1 and falls continuously (reference numeral 49a) until it enters the remaining portion 36 of the active region 16 to 1: 1 (reference numeral 49b).
Figur 1 1 zeigt den Verlauf des Wasseranteils im Reaktionsgas 48a und in der Membran 48b einer Brennstoffzelle in einem Diagramm sowie die erlaubte Mindestfeuchte der Membran 48 in Relation zur Länge I des aktiven Bereichs 16. Im Eintrittsbereich 34 wird durch die Figure 1 1 shows the course of the water content in the reaction gas 48a and in the membrane 48b of a fuel cell in a diagram and the minimum permissible moisture of the membrane 48 in relation to the length I of the active region 16. In the inlet region 34 is characterized by the
erfindungsgemäße Ausgestaltung eine Feuchte der Membran erreicht, die über der inventive design achieves a humidity of the membrane, which over the
erforderlichen Mindestfeuchte liegt, sodass bereits im Eintrittsbereich eine optimierte required minimum humidity, so that already in the entry area an optimized
Zellreaktion ablaufen kann. Die Feuchtigkeit steigt jedoch nicht soweit, dass der Durchtritt des Reaktionsgases durch die schmalen Kanäle 28 behindert werden würde. Cell reaction can proceed. However, the humidity does not increase so much that the passage of the reaction gas through the narrow channels 28 would be hindered.
Bezugszeichenliste LIST OF REFERENCE NUMBERS
10 Bipolarplatte 10 bipolar plate
12, 14 Separatorplatten  12, 14 separator plates
16 aktiver Bereich  16 active area
18, 20 Verteilerbereiche 18, 20 distribution areas
2, 24 Port für Reaktionsgase 2, 24 port for reaction gases
6 Port für Kühlmittel  6 port for coolant
28, 30,32 Kanäle für Betriebsmedien  28, 30.32 channels for operating media
34 Eintrittsbereich  34 entry area
36 Teilbereich  36 subarea
42 Strömungsrichtung  42 flow direction
44 Seite  44 page
46 Produktwasser  46 product water
48, 48a, 48b Kurve  48, 48a, 48b curve
49 Kanal-Steg-Verhältnis  49 channel-bridge ratio
49a, 49b Kanal-Steg-Verhältnis im Eintrittsbereich und im Teilbereich 49a, 49b Channel-to-bridge ratio in the inlet area and in the partial area
50,52 Bereich 50.52 area
54 Steg  54 footbridge
56a Kurve breite Stege 100%  56a curve wide bars 100%
58a Kurve schmale Stege 100%  58a curve narrow bars 100%
56b Kurve breite Stege 60%  56b curve wide bars 60%
58b Kurve schmale Stege 60%  58b curve narrow bars 60%
I Länge I length
B1 Breite Steg  B1 wide bridge
B2 Breite Kanal  B2 wide channel
B3 Breite Kanal plus Breite Steg  B3 width channel plus width bridge

Claims

K 23064 WO 2017/220552 - 1 1 - PCT/EP2017/065049 Patentansprüche K 23064 WO 2017/220552 - 1 1 - PCT / EP2017 / 065049 Claims
1. Bipolarplatte (10) für eine Brennstoffzelle, die zwei profilierte Separatorplatten (12, 14) besitzt, jeweils aufweisend einen aktiven Bereich (16) sowie zwei Verteilerbereiche (18, 20) zur Zu- und Ableitung von Reaktionsgasen und Kühlmitteln zu beziehungsweise aus dem aktiven Bereich (16), wobei die Separatorplatten (12, 14) derart ausgebildet sind, dass die Bipolarplatte (10) separate Kanäle (28, 30, 32) für die Reaktionsgase und das Kühlmittel aufweist, welche Ports (22, 24, 26) für Reaktionsgase und Kühlmittel beider A bipolar plate (10) for a fuel cell having two profiled separator plates (12, 14) each having an active region (16) and two manifold regions (18, 20) for supplying and discharging reaction gases and coolants to and from the same active region (16), wherein the separator plates (12, 14) are formed such that the bipolar plate (10) has separate channels (28, 30, 32) for the reaction gases and the coolant, which ports (22, 24, 26) for reaction gases and coolant both
Verteilerbereiche (18, 20) miteinander verbinden und die jeweils als offene rinnenartige Kanalstrukturen ausgebildet sind, wobei die zwei profilierten Separatorplatten (12, 14) derart übereinander angeordnet sind, dass in den aneinander grenzenden Seiten (28, 29) durch die Kanalstrukturen Kühlmittelkanäle (30), ausgeformt sind, wobei  Connecting distributor regions (18, 20) to each other and each formed as open channel-like channel structures, wherein the two profiled separator plates (12, 14) are arranged one above the other such that in the adjoining sides (28, 29) through the channel structures coolant channels (30 ), are formed
- die Kanäle (28,32) für ein Reaktionsgas oder beide Reaktionsgase in einem  - The channels (28,32) for a reaction gas or both reaction gases in one
Eintrittsbereich (34) des aktiven Bereichs (16) eine geringere Breite (B2) aufweisen als im restlichen Teilbereich (36) des aktiven Bereichs (16), wobei die Breite (B2) der Kanäle (28, 32) vom Anfang bis Ende des Eintrittsbereichs (34) kontinuierlich zunimmt, Entry area (34) of the active area (16) has a smaller width (B2) than in the remaining portion (36) of the active area (16), wherein the width (B2) of the channels (28, 32) from the beginning to the end of the inlet area (34) continuously increases,
- zwischen den Kanälen (28, 32) befindliche Stege (54) in dem Eintrittsbereich (34) eine größere Breite (B1 ) aufweisen als im restlichen Teilbereich (36) des aktiven Bereichs (16), - located between the channels (28, 32) webs (54) in the inlet region (34) have a greater width (B1) than in the remaining portion (36) of the active region (16),
- die Summe der Breite (B2) der Kanäle und der Breite (B1 ) der Stege (54) konstant ist, und  - the sum of the width (B2) of the channels and the width (B1) of the webs (54) is constant, and
- die Breite (B2) der Kanäle (28, 32) und die Breite (B1 ) der Stege (54) im gesamten restlichen Teilbereich (36) konstant sind.  - The width (B2) of the channels (28, 32) and the width (B1) of the webs (54) in the entire remaining portion (36) are constant.
2. Bipolarplatte (10) nach Anspruch 1 , dadurch gekennzeichnet, dass der Eintrittsbereich (34) 5 - 30 %, vorzugsweise 10 - 25 %, besonders bevorzugt 20% des aktiven Bereichs (16) einnimmt. 2. bipolar plate (10) according to claim 1, characterized in that the inlet region (34) 5 - 30%, preferably 10 - 25%, particularly preferably 20% of the active region (16) occupies.
3. Bipolarplatte (10) nach einem der Ansprüche 1 bis 2, dadurch gekennzeichnet, dass die Bipolarplatten (10) metallisch oder graphitisch sind 3. bipolar plate (10) according to one of claims 1 to 2, characterized in that the bipolar plates (10) are metallic or graphitic
4. Brennstoffzellenstapel Bipolarplatten (10) nach einem der Ansprüche 1 bis 3 aufweisend. K 23064 4. Fuel cell stack bipolar plates (10) according to one of claims 1 to 3 comprising. K 23064
WO 2017/220552 - - PCT/EP2017/065049  WO 2017/220552 - - PCT / EP2017 / 065049
5. Brennstoffzellensystem einen Brennstoffzellenstapel nach Anspruch 4 aufweisend. 5. Fuel cell system having a fuel cell stack according to claim 4.
6. Fahrzeug mit einem Brennstoffzellensystem, das einen Brennstoffzellenstapel nach Anspruch 5 aufweist. 6. A vehicle having a fuel cell system comprising a fuel cell stack according to claim 5.
EP17731159.4A 2016-06-24 2017-06-20 Bipolar plate having a variable width of the reaction channels in the inlet region of the active region, fuel cell stack and fuel cell system having bipolar plates of this type, as well as a vehicle Ceased EP3430662A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102016111638.6A DE102016111638A1 (en) 2016-06-24 2016-06-24 Bipolar plate with variable width of the reaction gas channels in the area of entry of the active area, fuel cell stack and fuel cell system with such bipolar plates and vehicle
PCT/EP2017/065049 WO2017220552A1 (en) 2016-06-24 2017-06-20 Bipolar plate having a variable width of the reaction channels in the inlet region of the active region, fuel cell stack and fuel cell system having bipolar plates of this type, as well as a vehicle

Publications (1)

Publication Number Publication Date
EP3430662A1 true EP3430662A1 (en) 2019-01-23

Family

ID=59078085

Family Applications (1)

Application Number Title Priority Date Filing Date
EP17731159.4A Ceased EP3430662A1 (en) 2016-06-24 2017-06-20 Bipolar plate having a variable width of the reaction channels in the inlet region of the active region, fuel cell stack and fuel cell system having bipolar plates of this type, as well as a vehicle

Country Status (7)

Country Link
US (1) US11108059B2 (en)
EP (1) EP3430662A1 (en)
JP (1) JP6745920B2 (en)
KR (1) KR102307256B1 (en)
CN (1) CN109417176B (en)
DE (1) DE102016111638A1 (en)
WO (1) WO2017220552A1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7176490B2 (en) * 2019-07-19 2022-11-22 トヨタ車体株式会社 fuel cell stack
DE102020203066A1 (en) * 2020-03-11 2021-09-16 Robert Bosch Gesellschaft mit beschränkter Haftung Bipolar plate with optimized mass flow
CN113839060A (en) * 2020-06-24 2021-12-24 未势能源科技有限公司 Fuel cell unit and fuel cell stack structure
DE102020128279A1 (en) 2020-10-28 2022-04-28 Audi Aktiengesellschaft bipolar plate and fuel cell stack
DE102021100186A1 (en) * 2021-01-08 2022-07-14 Audi Aktiengesellschaft Bipolar plate with channel splits and fuel cell stack present in the active area
DE102021214667A1 (en) 2021-12-20 2023-06-22 Robert Bosch Gesellschaft mit beschränkter Haftung Bipolar plate for an electrochemical cell and method of making a bipolar plate

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6756149B2 (en) 2001-10-23 2004-06-29 Ballard Power Systems Inc. Electrochemical fuel cell with non-uniform fluid flow design
JP4585737B2 (en) * 2002-08-12 2010-11-24 本田技研工業株式会社 Fuel cell
US7951507B2 (en) * 2004-08-26 2011-05-31 GM Global Technology Operations LLC Fluid flow path for stamped bipolar plate
TW200737576A (en) * 2006-03-24 2007-10-01 Asia Pacific Fuel Cell Tech Gas-inlet pressure adjustment structure for bipolar plate of fuel cell stack
DE102006027034A1 (en) 2006-06-08 2007-12-13 Daimlerchrysler Ag Fuel cell with a Separatorplatteneinheit and Separatorplatteneinheit
EP2026393A1 (en) 2007-08-13 2009-02-18 Nissan Motor Co., Ltd. Fuel cell separator and fuel cell
DE102008033211A1 (en) * 2008-07-15 2010-01-21 Daimler Ag Bipolar plate for a fuel cell assembly, in particular for the arrangement between two adjacent membrane-electrode assemblies
JP5589946B2 (en) 2011-04-20 2014-09-17 トヨタ自動車株式会社 Fuel cell and manufacturing method thereof

Also Published As

Publication number Publication date
US11108059B2 (en) 2021-08-31
KR20190021357A (en) 2019-03-05
KR102307256B1 (en) 2021-09-30
CN109417176A (en) 2019-03-01
JP6745920B2 (en) 2020-08-26
WO2017220552A1 (en) 2017-12-28
CN109417176B (en) 2022-07-08
DE102016111638A1 (en) 2017-12-28
JP2019518317A (en) 2019-06-27
US20190229347A1 (en) 2019-07-25

Similar Documents

Publication Publication Date Title
WO2017220552A1 (en) Bipolar plate having a variable width of the reaction channels in the inlet region of the active region, fuel cell stack and fuel cell system having bipolar plates of this type, as well as a vehicle
DE102008013439B4 (en) Fuel cell stack and bipolar plate for a fuel cell
WO2017186770A1 (en) Bipolar plate which has reactant gas channels with variable cross-sectional areas, fuel cell stack, and vehicle comprising such a fuel cell stack
EP3378117B1 (en) Bipolar plate having asymmetrical sealing sections, and fuel cell stack having such a bipolar plate
WO2017025555A1 (en) Bipolar plate and a fuel cell stack comprising same
DE102015225228A1 (en) Bipolar plate for a fuel cell and fuel cell stack with such
EP3884535B1 (en) Fuel cell plate, bipolar plate and fuel cell device
DE112007000282T5 (en) fuel cell
DE10220183A1 (en) Polymer electrolyte fuel cell has stacked unit cells comprising water electrolysis and fuel cell portions within single plane of unit cell and water passage in interconnector to feed water to water electrolysis portion
DE102017101954A1 (en) Membrane electrode assembly and fuel cell stack
EP4154335B1 (en) Bipolar plate and fuel cell stack
EP3736894B1 (en) Bipolar plate for fuel cells, fuel cell stack comprising such bipolar plates and vehicle comprising such a fuel cell stack
WO2017085030A1 (en) Fuel cell stack having bipolar plates, and fuel cell system
DE102019205069A1 (en) Bipolar plate for fuel cells, fuel cell stacks with such bipolar plates and vehicles with such a fuel cell stack
DE102018211078B3 (en) Bipolar plate for fuel cells with three individual plates, and fuel cell and fuel cell stack with such bipolar plates
EP4165705B1 (en) Flow field plate and fuel cell stack
DE102012011441A1 (en) Membrane electrode unit for a fuel cell
DE102016201707A1 (en) Bipolar plate for fuel cells with improved structure, fuel cell stack with such bipolar plates and vehicle with such a fuel cell stack
DE102020114066A1 (en) Bipolar plate
DE102015222245A1 (en) Polar plate for a fuel cell stack
WO2022090128A1 (en) Individual cell and fuel cell stack having elastic structures for evenly distributing operating media
DE102019206118A1 (en) Bipolar plate for fuel cells comprising elastic structural elements on the electrode side
WO2021233647A1 (en) Bipolar plate
DE102019205579A1 (en) Bipolar plate for fuel cells, fuel cell stacks with such bipolar plates and vehicles with such a fuel cell stack
DE102018218076A1 (en) Membrane electrode arrangement for a fuel cell, fuel cell stack and vehicle with such a fuel cell stack

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20181017

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
17Q First examination report despatched

Effective date: 20190905

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

REG Reference to a national code

Ref country code: DE

Ref legal event code: R003

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED

18R Application refused

Effective date: 20201217