WO2021198184A1 - Bipolar plate for an electrochemical device, and electrochemical device - Google Patents

Bipolar plate for an electrochemical device, and electrochemical device Download PDF

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Publication number
WO2021198184A1
WO2021198184A1 PCT/EP2021/058171 EP2021058171W WO2021198184A1 WO 2021198184 A1 WO2021198184 A1 WO 2021198184A1 EP 2021058171 W EP2021058171 W EP 2021058171W WO 2021198184 A1 WO2021198184 A1 WO 2021198184A1
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WO
WIPO (PCT)
Prior art keywords
bipolar plate
flow field
channel
fluid medium
bypass
Prior art date
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PCT/EP2021/058171
Other languages
German (de)
French (fr)
Inventor
Thomas Kiupel
Peter Stahl
Jürgen KRAFT
Original Assignee
Ekpo Fuel Cell Technologies Gmbh
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Publication date
Application filed by Ekpo Fuel Cell Technologies Gmbh filed Critical Ekpo Fuel Cell Technologies Gmbh
Publication of WO2021198184A1 publication Critical patent/WO2021198184A1/en

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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
    • 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
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0247—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the form
    • H01M8/0254—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the form corrugated or undulated
    • 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

Definitions

  • the present invention relates to a bipolar plate for an electrochemical device, the bipolar plate comprising a flow field bipolar plate layer on which a flow field for a fluid medium is formed, the flow field comprising a flow field channel through which the fluid medium can flow along a flow direction and which comprises a flow field channel section for the fluid medium which, in the assembled state of the bipolar plate, is open to an electrochemically active unit of the electrochemical device.
  • the efficiency and power output of such an electrochemical Vorrich device depends on an adequate supply of the electrochemically active unit of the electrochemical device with the fluid reaction media, on the temperature of the electrochemically active unit, on the water content of the electrochemically active unit and on other factors.
  • the electrochemically active species (in particular hydrogen or oxygen) of the fluid media supplied to the electrochemical device which can consist of a mixture of different fluids (for example in the form of air), must be transferred to the reactive points of the electrochemically active unit, in particular to the anode and to the cathode.
  • a measure of the supply of the electrodes (anode and cathode) of the electrochemically active unit with the reactive fluid media is the concentration of the respective electrochemically active species.
  • the unconsumed species, the non-electrochemically active species and the products from the electrochemical reaction taking place in the electrochemically active unit are carried away again by the flow field. If the discharge of non-electrochemically active species and of products of the electrochemical reaction is not sufficient, reactive sites of the electrochemically active unit are blocked by products remaining there or by substances inert for the electrochemical reaction, thereby increasing the performance and efficiency of the electrochemical device decreases.
  • each reactive fluid medium is fed to the flow field in an edge region of the bipolar plate and removed again from the flow field at an opposite edge region of the bipolar plate.
  • the concentration of the electrochemically active species decreases continuously between the two edge areas of the bipolar plate.
  • the present invention is based on the object of creating a bipolar plate of the type mentioned at the outset which enables the concentration of the electrochemically active species to be homogenized in a fluid medium to which the flow field is assigned, along the direction of flow of the fluid medium through the flow field, and so on increases the efficiency of the electrochemical device.
  • the bipolar plate comprises a bypass channel for the fluid medium, the bypass channel having a bypass inlet arranged upstream of the flow field channel section through which the fluid medium enters the Bypass channel can enter, and a downstream of the flow field channel section arranged bypass outlet, through which the fluid medium can exit from the bypass channel into the flow field channel, and wherein the bypass channel is designed to be closed with respect to the electrochemically active unit.
  • the bypass channel enables the fluid medium to be guided past the reactive points of the electrochemically active unit of the electrochemical device which adjoin the flow field channel section, so that this portion of the fluid medium flowing through the bypass channel does not adhere to that in the electrochemically active unit Unit taking place electrochemical reaction is involved.
  • the concentration of the electrochemically active species is therefore not reduced in the portion of the fluid medium flowing through the bypass channel.
  • the concentration of the electrochemically active species in the Area of the bypass outlet and downstream of the bypass outlet can be increased in a targeted manner, whereby the power generation and the efficiency of the electrochemical device's rule is increased.
  • the electrochemical device can in particular be designed as a fuel cell device, preferably a PEM (polymer electrolyte membrane) fuel cell device, as an electrolysis cell or as a redox flow battery.
  • a fuel cell device preferably a PEM (polymer electrolyte membrane) fuel cell device, as an electrolysis cell or as a redox flow battery.
  • PEM polymer electrolyte membrane
  • the fluid medium which is passed through the bypass channel and contains an electrochemically active species, can in particular be an anode gas or a cathode gas of the electrochemical device.
  • the bypass channel is delimited by the flow field bipolar plate layer, on which the flow field for the fluid medium is formed, and by a further bipolar plate layer of the bipolar plate.
  • the bipolar plate has two or more bipolar plate layers.
  • the flow field bipolar plate layer and the further bipolar plate layer are preferably connected to one another in a substantially fluid-tight manner along a joint line bordering the bypass channel.
  • Such a joining line can in particular be a soldering line or a welding line.
  • a fluid channel for a further fluid medium is formed between the flow field bipolar plate layer and the further bipolar plate layer.
  • bypass channel is separated from the fluid channel by an essentially fluid-tight joining line.
  • the fluid channel is designed to be closed with respect to the electrochemically active unit.
  • the further fluid medium which flows through the fluid channel is therefore preferably a fluid medium which does not contain any electrochemically active species which are involved in the electrochemical reaction taking place in the electrochemically active unit of the electrochemical device.
  • the further fluid medium is a cooling medium.
  • the fluid medium flowing through the bypass channel is preferably an anode gas or a cathode gas for the electrochemical device.
  • the bypass channel is delimited by a web of the flow field which laterally delimits a flow field channel of the flow field.
  • the bypass outlet can be arranged in particular on a flank of the web.
  • bypass outlet is arranged at a crest of the web.
  • the web preferably rests on the electrochemically active unit of the electrochemical device.
  • the bypass entry can be arranged in particular on an end wall of the web.
  • bypass inlet is also arranged on a flank of the web, preferably at a point on the web that is arranged upstream of the bypass outlet.
  • the flow field comprises a plurality of flow field channels through which the fluid medium can flow parallel to one another.
  • the bipolar plate according to the invention is particularly suitable for use in an electrochemical device which comprises at least one electrochemically active unit and at least one bipolar plate according to the invention, the flow field channel section of which is open to the electrochemically active unit.
  • the bypass channel of the bipolar plate according to the invention can be a channel which is conventionally provided for a coolant to flow through the electrochemical device, but which is hydraulically isolated from the coolant flow field of the bipolar plate by a joining process by means of essentially fluid-tight joining lines.
  • the bypass channel with the bypass inlet and the bypass outlet serves as a channel carrying a fluid medium in which a fluid medium can be transported downstream without contact to reactive sites of the electrochemically active unit of the electrochemical device.
  • the fluid entering the bypass channel represents a fraction of the fluid which flows through the flow field channels of the flow field which is assigned to the fluid medium in question.
  • the flow of the fluid medium through the bypass channel preferably runs parallel to the flow of the fluid medium through the flow field channel section, which is in fluid connection with the reactive points of the electrochemically active unit.
  • the bypass inlet and / or the bypass outlet are preferably generated by a cutting process, in particular a laser cutting process, on the bipolar plate, in particular on the flow field bipolar plate layer on which the flow field for the fluid medium is formed.
  • the electrochemically active unit of the electrochemical device preferably comprises a polymer electrolyte membrane (PEM).
  • PEM polymer electrolyte membrane
  • the flow field bipolar plate layer and / or the further bipolar plate layer of the bipolar plate are preferably formed from a metallic material. Further features and advantages of the invention are the subject of the following description and the graphic representation ofwhosbei play.
  • FIG. 1 shows a fragmentary schematic plan view of a bipolar plate for an electrochemical device, on which a flow field for a fluid medium is formed;
  • FIG. 2 shows a cross section through the bipolar plate from FIG. 1 and an electrochemically active unit of the electrochemical device, along the line 2-2 in FIG. 1;
  • FIG. 3 shows a partial schematic plan view of a second embodiment of a bipolar plate for an electrochemical device
  • FIG. 4 shows a cross section through the bipolar plate from FIG. 3 and an electrochemically active unit of the electrochemical device, along the line 4-4 in FIG. 3.
  • An electrochemical device shown in detail in FIGS. 1 and 2 and designated as a whole by 100, for example a fuel cell stack or an electrolyser, comprises a stack which contains several electrochemical units 104, one after the other in a stacking direction 102. for example fuel cell units or electrolysis units, and a tensioning device (not shown) for applying a tensioning force directed parallel to the stacking direction 102 to the electrochemical units 104.
  • Each of the electrochemical units 104 of the electrochemical device 100 each comprises a bipolar plate 106.
  • each bipolar plate 106 comprises a flow field bipolar plate layer 108, on which a flow field 110 for a fluid medium is formed, and a further bipolar plate layer 112, which is fixed fluid-tight, for example by a weld seam arrangement, to the flow field bipolar plate layer 108.
  • the flow field bipolar plate layer 108 has webs 114 and channel base sections 116 located between two webs 114 each.
  • Each of the webs 114 each has a dome 118 with which the web 114 rests against an electrochemically active unit 120 of the electrochemical device 100 adjacent to the bipolar plate 106.
  • Such an electrochemically active unit 120 can in particular be designed as a membrane electrode arrangement (MEA) 122.
  • MEA membrane electrode arrangement
  • Each dome 118 rests with a contact surface 124, which is oriented essentially perpendicular to the stacking direction 102, essentially flat on a boundary surface 126 of the electrochemically active unit 120 facing the bipolar plate 106, which is also oriented essentially perpendicular to the stacking direction 102.
  • each web 114 comprises two flanks 128 which are inclined at an acute angle with respect to the stacking direction 102.
  • a channel base section 116 of the flow field bipolar plate layer 108 which connects the two adjacent webs 114 to one another, extends between the outer edges 130 of two adjacent webs 114 facing away from the respective tip 118.
  • Each of the webs 114 extends along a web longitudinal direction 132, which is oriented essentially perpendicular to the stacking direction 102.
  • each web 114 ends at its two end regions 134 at a respective end wall 136, which - like the lateral flanks 128 of the respective web 114 - is opposite both to the dome 118 and to the stacking direction 102 are inclined at an acute angle.
  • two adjacent webs 114 and the channel base section 116 connecting the two webs 114 together with the electrochemically active unit 120 each delimit a flow field channel 138 of the flow field 110.
  • Each flow field channel 138 of the flow field 110 can be flowed through by the fluid medium to which the flow field 110 is assigned along a flow direction 140 which, within a flow field channel 138, is essentially parallel to the web longitudinal directions 132 of the webs 114 delimiting the relevant flow field channel 138 Strö flow field 110 is aligned.
  • the flow field channels 138 of the flow field 110 open at their upstream end into a medium supply area 142 of the flow field 110 and at their downstream end into a medium discharge area 144 of the flow field 110.
  • the fluid medium enters the medium supply region 142 of the flow field 110 through a medium supply channel (not shown, which preferably runs essentially parallel to the stacking direction 102) where it is divided into the various flow field channels 138 ver and flows through the same along the flow direction 140.
  • the fluid medium can in particular be an anode gas or a cathode gas for the electrochemical device 100.
  • the fluid medium passes from the flow field channels 138 to the electrochemically active unit 120, where the respective electrochemically active species from the fluid medium is consumed in the course of the electrochemical reactions taking place in the electrochemically active unit 120, so that the concentration of the electrochemically active species in the fluid medium flowing through the flow field channels 138 decreases along the flow direction 140.
  • the bipolar plate 106 comprises at least one bypass channel 146 for the fluid medium to which the flow field 110 is assigned.
  • the bypass channel 146 is delimited by a web 114a and a web 114a 'opposite the web 114a, which web is formed in the further bipolar plate layer 112 (see FIG. 2).
  • the web 114a ' likewise has a dome 118' with a contact surface 124 'oriented essentially perpendicular to the stacking direction 102 and two flanks 128' inclined at an acute angle relative to the stacking direction 102.
  • the flow field bipolar plate layer 108 and the further bipolar plate layer 112 are connected to one another in a fluid-tight manner along one or more joining lines 148 bordering the bypass channel 146.
  • every material joining method can be used to produce the at least one joining line 148.
  • the joining line 148 is a soldering line or a welding line 150.
  • a weld line 150 can in particular be produced on the bipolar plate 106 by a laser welding process.
  • a fluid channel 152 for a further fluid medium is formed between the flow field bipolar plate layer 108 and the further bipolar plate layer 112.
  • This further fluid medium is different from the fluid medium to which the flow field 110 is assigned.
  • the further fluid medium can in particular be a cooling medium for cooling the electrochemical device 100.
  • the fluid channel 152 through which the further fluid medium can flow, is separated from the bypass channel 146 by one of the essentially fluid-tight joining lines 148.
  • the fluid channel 152 through which the further fluid medium can flow is designed to be closed with respect to the electrochemically active unit 120, so that the further fluid medium, in particular the cooling medium, cannot pass from the fluid channel 152 into the electrochemically active unit 120.
  • the bypass channel 146 comprises a bypass inlet 154 through which the fluid medium to which the flow field 110 is assigned can enter the bypass channel 146, and one downstream of the bypass inlet 154 arranged bypass outlet exits 156, through which the fluid medium can exit from the bypass channel 146 into the adjacent flow field channel 138a.
  • the bypass inlet 154 is formed, for example, as a passage opening in the end wall 136a of the web 114a, which is arranged in the upstream end region 134 of the web 114a.
  • the bypass outlet 156 is designed, for example, as a passage opening in the flank 128a of the web 114a facing the flow field channel 138a.
  • a flow field channel section 158 of the flow field channel 138a is bypassed by means of the bypass channel 146, so that the portion of the fluid medium which passes through the bypass inlet 154 into the Bypass channel 146 enters and exits from bypass outlet 156 again from bypass channel 146 into flow field channel 138a, does not flow through flow field channel section 158 and thus cannot get out of flow field channel section 158 to electrochemically active unit 120.
  • the portion of the fluid medium flowing through the bypass channel 146 cannot pass from the bypass channel 146 into the electrochemically active unit 120 either, because the bypass channel 146 is designed to be closed with respect to the electrochemically active unit 120.
  • the concentration of the electrochemically active species in the fluid medium therefore remains in the portion of the fluid medium flowing through the bypass channel 146, so that by supplying this portion of the fluid medium from the bypass channel 146 through the bypass outlet 156 into the downstream of the part of the flow field channel 138a lying in the flow field channel section 158, the reduction in the concentration of the electrochemically active species in the fluid medium flowing through the flow field channel 138a is at least partially compensated for.
  • a second embodiment of an electrochemical device 108 shown in FIGS. 3 and 4, which comprises a bipolar plate 106, which in turn includes a bypass channel 146 for a fluid medium, differs from the first embodiment shown in FIGS. 1 and 2 in this way that the bypass outlet 156 of the bypass channel 146 is not formed in a flank 128a of the web 114a facing the flow field channel 138a, but in the dome 118 of the web 114a, so that the portion of the fluid medium flowing through the bypass channel 146 which the flow field 110 is assigned, is fed directly to the electrochemically active unit 120 in this embodiment.

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Abstract

In order to create a bipolar plate for an electrochemical device, comprising a flow field bipolar plate layer, on which a flow field for a fluid medium is formed, wherein the flow field comprises a flow field channel, through which the fluid medium can flow along a direction of flow and which comprises a flow field channel portion open towards an electrochemically active unit of the electrochemical device, which bipolar plate allows homogenization of the concentration of the electrochemically active species in the fluid medium along its direction of flow through the flow field and thereby increases the efficiency of the electrochemical device, it is proposed that the bipolar plate comprises a bypass channel for the fluid medium, wherein the bypass channel comprises a bypass inlet which is disposed upstream of the flow field channel portion and through which the fluid medium can enter the bypass channel, and a bypass outlet which is disposed downstream of the flow field channel portion and through which the fluid medium can flow out of the bypass channel into the flow field channel, and wherein the bypass channel is designed to be closed against an electrochemically active unit.

Description

Bipolarplatte für eine elektrochemische Vorrichtung und elektrochemische Vorrichtung Electrochemical device bipolar plate and electrochemical device
Die vorliegende Erfindung betrifft eine Bipolarplatte für eine elektrochemische Vorrichtung, wobei die Bipolarplatte eine Strömungsfeld-Bipolarplattenlage, an welcher ein Strömungsfeld für ein fluides Medium ausgebildet ist, umfasst, wobei das Strömungsfeld einen Strömungsfeldkanal umfasst, welcher von dem fluiden Medium längs einer Strömungsrichtung durchströmbar ist und welcher einen Strömungsfeldkanalabschnitt für das fluide Medium umfasst, der im montierten Zustand der Bipolarplatte zu einer elektrochemisch aktiven Einheit der elektrochemischen Vorrichtung hin offen ist. The present invention relates to a bipolar plate for an electrochemical device, the bipolar plate comprising a flow field bipolar plate layer on which a flow field for a fluid medium is formed, the flow field comprising a flow field channel through which the fluid medium can flow along a flow direction and which comprises a flow field channel section for the fluid medium which, in the assembled state of the bipolar plate, is open to an electrochemically active unit of the electrochemical device.
Die Effizienz und Leistungsabgabe einer solchen elektrochemischen Vorrich tung ist von einer ausreichenden Versorgung der elektrochemisch aktiven Ein heit der elektrochemischen Vorrichtung mit den fluiden Reaktionsmedien, von der Temperatur der elektrochemisch aktiven Einheit, vom Wasseranteil der elektrochemisch aktiven Einheit und von weiteren Faktoren abhängig. The efficiency and power output of such an electrochemical Vorrich device depends on an adequate supply of the electrochemically active unit of the electrochemical device with the fluid reaction media, on the temperature of the electrochemically active unit, on the water content of the electrochemically active unit and on other factors.
Dabei müssen die elektrochemisch aktiven Spezies (insbesondere Wasserstoff oder Sauerstoff) der der elektrochemischen Vorrichtung zugeführten fluiden Medien, welche aus einem Gemisch verschiedener Fluide bestehen können (beispielsweise in Form von Luft), an die reaktiven Stellen der elektrochemisch aktiven Einheit, insbesondere an die Anode und an die Kathode, geführt werden. The electrochemically active species (in particular hydrogen or oxygen) of the fluid media supplied to the electrochemical device, which can consist of a mixture of different fluids (for example in the form of air), must be transferred to the reactive points of the electrochemically active unit, in particular to the anode and to the cathode.
Ein Maß für die Versorgung der Elektroden (Anode und Kathode) der elektro chemisch aktiven Einheit mit den reaktiven fluiden Medien ist die Konzentra tion der jeweiligen elektrochemisch aktiven Spezies. Die unverbrauchten Spezies, die nicht elektrochemisch aktiven Spezies und die Produkte aus der in der elektrochemisch aktiven Einheit ablaufenden elektrochemischen Reaktion (beispielsweise Wasser) werden durch das Strömungsfeld wieder ausgetragen. Geschieht der Austrag von nicht elektrochemisch aktiven Spezies und von Pro dukten der elektrochemischen Reaktion nicht in ausreichendem Maße, so werden reaktive Stellen der elektrochemisch aktiven Einheit durch dort ver bleibende Produkte oder durch für die elektrochemische Reaktion inerte Stoffe blockiert, wodurch die Leistung und die Effizienz der elektrochemischen Vor richtung sinkt. A measure of the supply of the electrodes (anode and cathode) of the electrochemically active unit with the reactive fluid media is the concentration of the respective electrochemically active species. The unconsumed species, the non-electrochemically active species and the products from the electrochemical reaction taking place in the electrochemically active unit (for example water) are carried away again by the flow field. If the discharge of non-electrochemically active species and of products of the electrochemical reaction is not sufficient, reactive sites of the electrochemically active unit are blocked by products remaining there or by substances inert for the electrochemical reaction, thereby increasing the performance and efficiency of the electrochemical device decreases.
Bei bekannten Bipolarplatten für eine elektrochemische Vorrichtung wird jedes reaktive fluide Medium dem Strömungsfeld in einem Randbereich der Bipolar platte zugeführt und an einem gegenüberliegenden Randbereich der Bipolar platte wieder aus dem Strömungsfeld abgeführt. Zwischen den beiden Rand bereichen der Bipolarplatte nimmt die Konzentration der elektrochemisch akti ven Spezies kontinuierlich ab. In known bipolar plates for an electrochemical device, each reactive fluid medium is fed to the flow field in an edge region of the bipolar plate and removed again from the flow field at an opposite edge region of the bipolar plate. The concentration of the electrochemically active species decreases continuously between the two edge areas of the bipolar plate.
Der vorliegenden Erfindung liegt die Aufgabe zugrunde, eine Bipolarplatte der eingangs genannten Art zu schaffen, welche eine Homogenisierung der Kon zentration der elektrochemisch aktiven Spezies in einem fluiden Medium, welchem das Strömungsfeld zugeordnet ist, längs der Strömungsrichtung des fluiden Mediums durch das Strömungsfeld ermöglicht und so die Effizienz der elektrochemischen Vorrichtung erhöht. The present invention is based on the object of creating a bipolar plate of the type mentioned at the outset which enables the concentration of the electrochemically active species to be homogenized in a fluid medium to which the flow field is assigned, along the direction of flow of the fluid medium through the flow field, and so on increases the efficiency of the electrochemical device.
Diese Aufgabe wird bei einer Bipolarplatte mit den Merkmalen des Oberbegriffs von Anspruch 1 erfindungsgemäß dadurch gelöst, dass die Bipolarplatte einen Bypasskanal für das fluide Medium umfasst, wobei der Bypasskanal einen stromaufwärts von dem Strömungsfeldkanalab schnitt angeordneten Bypass-Eintritt, durch welchen das fluide Medium in den Bypasskanal eintreten kann, und einen stromabwärts von dem Strömungsfeld kanalabschnitt angeordneten Bypass-Austritt, durch welchen das fluide Medium aus dem Bypasskanal in den Strömungsfeldkanal austreten kann, um fasst, und wobei der Bypasskanal gegenüber der elektrochemisch aktiven Einheit ge schlossen ausgebildet ist. Der Bypasskanal ermöglicht es, dass das fluide Medium an den reaktiven Stellen der elektrochemisch aktiven Einheit der elektrochemischen Vorrich tung, welche an den Strömungsfeldkanalabschnitt angrenzen, vorbeigeführt wird, so dass dieser durch den Bypasskanal strömende Anteil des fluiden Me diums nicht an der in der elektrochemisch aktiven Einheit stattfindenden elektrochemischen Reaktion beteiligt ist. Die Konzentration der elektroche misch aktiven Spezies verringert sich daher in dem durch den Bypasskanal strömenden Anteil des fluiden Mediums nicht. Durch die spätere Vermischung des durch den Bypasskanal strömenden Anteils des fluiden Mediums mit dem durch den Strömungsfeldkanalabschnitt strömenden Anteil des fluiden Me diums, welches an der in der elektrochemisch aktiven Einheit der elektroche mischen Vorrichtung stattfindenden elektrochemischen Reaktion teilnimmt, kann die Konzentration der elektrochemisch aktiven Spezies im Bereich des Bypass-Austritts und stromabwärts von dem Bypass-Austritt gezielt erhöht werden, wodurch die Leistungserzeugung und die Effizienz der elektrochemi schen Vorrichtung gesteigert wird. This object is achieved in a bipolar plate with the features of the preamble of claim 1 according to the invention in that the bipolar plate comprises a bypass channel for the fluid medium, the bypass channel having a bypass inlet arranged upstream of the flow field channel section through which the fluid medium enters the Bypass channel can enter, and a downstream of the flow field channel section arranged bypass outlet, through which the fluid medium can exit from the bypass channel into the flow field channel, and wherein the bypass channel is designed to be closed with respect to the electrochemically active unit. The bypass channel enables the fluid medium to be guided past the reactive points of the electrochemically active unit of the electrochemical device which adjoin the flow field channel section, so that this portion of the fluid medium flowing through the bypass channel does not adhere to that in the electrochemically active unit Unit taking place electrochemical reaction is involved. The concentration of the electrochemically active species is therefore not reduced in the portion of the fluid medium flowing through the bypass channel. Due to the later mixing of the portion of the fluid medium flowing through the bypass channel with the portion of the fluid medium flowing through the flow field channel section, which takes part in the electrochemical reaction taking place in the electrochemically active unit of the electrochemical device, the concentration of the electrochemically active species in the Area of the bypass outlet and downstream of the bypass outlet can be increased in a targeted manner, whereby the power generation and the efficiency of the electrochemical device's rule is increased.
Die elektrochemische Vorrichtung kann insbesondere als eine Brennstoff zellenvorrichtung, vorzugsweise eine PEM(Polymer-Elektrolyt-Membran)- Brennstoffzellenvorrichtung, als eine Elektrolysezelle oder als eine Redox- Flow-Batterie, ausgebildet sein. The electrochemical device can in particular be designed as a fuel cell device, preferably a PEM (polymer electrolyte membrane) fuel cell device, as an electrolysis cell or as a redox flow battery.
Das fluide Medium, welches durch den Bypasskanal geführt wird und eine elektrochemisch aktive Spezies enthält, kann insbesondere ein Anodengas oder ein Kathodengas der elektrochemischen Vorrichtung sein. The fluid medium, which is passed through the bypass channel and contains an electrochemically active species, can in particular be an anode gas or a cathode gas of the electrochemical device.
Bei einer bevorzugten Ausgestaltung der Erfindung ist vorgesehen, dass der Bypasskanal durch die Strömungsfeld-Bipolarplattenlage, an welcher das Strömungsfeld für das fluide Medium ausgebildet ist, und durch eine weitere Bipolarplattenlage der Bipolarplatte begrenzt ist. Die Bipolarplatte weist in diesem Fall also zwei oder mehr Bipolarplattenlagen auf. In a preferred embodiment of the invention, it is provided that the bypass channel is delimited by the flow field bipolar plate layer, on which the flow field for the fluid medium is formed, and by a further bipolar plate layer of the bipolar plate. In this case, the bipolar plate has two or more bipolar plate layers.
Die Strömungsfeld-Bipolarplattenlage und die weitere Bipolarplattenlage sind vorzugsweise längs einer den Bypasskanal berandenden Fügelinie im Wesent lichen fluiddicht miteinander verbunden. The flow field bipolar plate layer and the further bipolar plate layer are preferably connected to one another in a substantially fluid-tight manner along a joint line bordering the bypass channel.
Ein solche Fügelinie kann insbesondere eine Lötlinie oder eine Schweißlinie sein. Such a joining line can in particular be a soldering line or a welding line.
Ferner kann vorgesehen sein, dass zwischen der Strömungsfeld- Bipolarplattenlage und der weiteren Bipolarplattenlage ein Fluidkanal für ein weiteres fluides Medium ausgebildet ist. Furthermore, it can be provided that a fluid channel for a further fluid medium is formed between the flow field bipolar plate layer and the further bipolar plate layer.
Dabei ist vorzugsweise vorgesehen, dass der Bypasskanal von dem Fluidkanal durch eine im Wesentlichen fluiddichte Fügelinie getrennt ist. It is preferably provided that the bypass channel is separated from the fluid channel by an essentially fluid-tight joining line.
Vorzugsweise ist vorgesehen, dass der Fluidkanal gegenüber der elektroche misch aktiven Einheit geschlossen ausgebildet ist. It is preferably provided that the fluid channel is designed to be closed with respect to the electrochemically active unit.
Das weitere fluide Medium, welches durch den Fluidkanal strömt, ist daher vorzugsweise ein fluides Medium, das keine elektrochemisch aktive Spezies enthält, welche an der in der elektrochemisch aktiven Einheit der elektroche mischen Vorrichtung ablaufenden elektrochemischen Reaktion beteiligt ist. The further fluid medium which flows through the fluid channel is therefore preferably a fluid medium which does not contain any electrochemically active species which are involved in the electrochemical reaction taking place in the electrochemically active unit of the electrochemical device.
Insbesondere kann vorgesehen sein, dass das weitere fluide Medium ein Kühlmedium ist. In particular, it can be provided that the further fluid medium is a cooling medium.
Das durch den Bypasskanal strömende fluide Medium ist vorzugsweise ein Anodengas oder ein Kathodengas für die elektrochemische Vorrichtung. Bei einer bevorzugten Ausgestaltung der Erfindung ist vorgesehen, dass der Bypasskanal durch einen Steg des Strömungsfeldes, welcher einen Strö mungsfeldkanal des Strömungsfeldes seitlich begrenzt, begrenzt ist. The fluid medium flowing through the bypass channel is preferably an anode gas or a cathode gas for the electrochemical device. In a preferred embodiment of the invention it is provided that the bypass channel is delimited by a web of the flow field which laterally delimits a flow field channel of the flow field.
Dabei kann der Bypass-Austritt insbesondere an einer Flanke des Steges an geordnet sein. The bypass outlet can be arranged in particular on a flank of the web.
Alternativ oder ergänzend hierzu kann vorgesehen sein, dass der Bypass- Austritt an einer Kuppe des Steges angeordnet ist. As an alternative or in addition to this, it can be provided that the bypass outlet is arranged at a crest of the web.
Mit einer solchen Kuppe liegt der Steg vorzugsweise an der elektrochemisch aktiven Einheit der elektrochemischen Vorrichtung an. With such a dome, the web preferably rests on the electrochemically active unit of the electrochemical device.
Der Bypass- Eintritt kann insbesondere an einer Stirnwand des Steges ange ordnet sein. The bypass entry can be arranged in particular on an end wall of the web.
Alternativ hierzu kann vorgesehen sein, dass der Bypass-Eintritt ebenfalls an einer Flanke des Steges angeordnet ist, vorzugsweise an einer stromaufwärts von dem Bypass-Austritt angeordneten Stelle des Steges. As an alternative to this, it can be provided that the bypass inlet is also arranged on a flank of the web, preferably at a point on the web that is arranged upstream of the bypass outlet.
Bei einer bevorzugten Ausgestaltung der Erfindung ist vorgesehen, dass das Strömungsfeld mehrere parallel zueinander von dem fluiden Medium durch- strömbare Strömungsfeldkanäle umfasst. In a preferred embodiment of the invention it is provided that the flow field comprises a plurality of flow field channels through which the fluid medium can flow parallel to one another.
Die erfindungsgemäße Bipolarplatte eignet sich insbesondere zur Verwendung in einer elektrochemischen Vorrichtung, welche mindestens eine elektroche misch aktive Einheit und mindestens eine erfindungsgemäße Bipolarplatte, deren Strömungsfeldkanalabschnitt zu der elektrochemisch aktiven Einheit hin offen ist, umfasst. Der Bypasskanal der erfindungsgemäßen Bipolarplatte kann ein Kanal sein, welcher herkömmlicherweise für die Durchströmung mit einem Kühlmittel der elektrochemischen Vorrichtung vorgesehen ist, jedoch durch einen Fügepro zess mittels im Wesentlichen fluiddichter Fügelinien hydraulisch von dem Kühlmittel-Strömungsfeld der Bipolarplatte isoliert ist. The bipolar plate according to the invention is particularly suitable for use in an electrochemical device which comprises at least one electrochemically active unit and at least one bipolar plate according to the invention, the flow field channel section of which is open to the electrochemically active unit. The bypass channel of the bipolar plate according to the invention can be a channel which is conventionally provided for a coolant to flow through the electrochemical device, but which is hydraulically isolated from the coolant flow field of the bipolar plate by a joining process by means of essentially fluid-tight joining lines.
Der Bypasskanal mit dem Bypass-Eintritt und dem Bypass-Austritt dient als ein ein fluides Medium führender Kanal, in welchem ein fluides Medium ohne Kontakt zu reaktiven Stellen der elektrochemisch aktiven Einheit der elektro chemischen Vorrichtung stromabwärts transportiert werden kann. The bypass channel with the bypass inlet and the bypass outlet serves as a channel carrying a fluid medium in which a fluid medium can be transported downstream without contact to reactive sites of the electrochemically active unit of the electrochemical device.
Dabei stellt das in den Bypasskanal eintretende Fluid einen Bruchteil des Fluids dar, welches durch die Strömungsfeldkanäle des Strömungsfelds, welches dem betreffenden fluiden Medium zugeordnet ist, strömt. The fluid entering the bypass channel represents a fraction of the fluid which flows through the flow field channels of the flow field which is assigned to the fluid medium in question.
Die Strömung des fluiden Mediums durch den Bypasskanal verläuft vorzugs weise parallel zu der Strömung des fluiden Mediums durch den Strömungs feldkanalabschnitt, welcher mit den reaktiven Stellen der elektrochemisch aktiven Einheit in Fluidverbindung steht. The flow of the fluid medium through the bypass channel preferably runs parallel to the flow of the fluid medium through the flow field channel section, which is in fluid connection with the reactive points of the electrochemically active unit.
Der Bypass- Eintritt und/oder der Bypass-Austritt werden vorzugsweise durch einen Schneidvorgang, insbesondere einen Laser-Schneidvorgang, an der Bi polarplatte, insbesondere an der Strömungsfeld-Bipolarplattenlage, an welcher das Strömungsfeld für das fluide Medium ausgebildet ist, erzeugt. The bypass inlet and / or the bypass outlet are preferably generated by a cutting process, in particular a laser cutting process, on the bipolar plate, in particular on the flow field bipolar plate layer on which the flow field for the fluid medium is formed.
Die elektrochemisch aktive Einheit der elektrochemischen Vorrichtung umfasst vorzugsweise eine Polymer-Elektrolyt-Membran (PEM). The electrochemically active unit of the electrochemical device preferably comprises a polymer electrolyte membrane (PEM).
Die Strömungsfeld-Bipolarplattenlage und/oder die weitere Bipolarplattenlage der Bipolarplatte sind vorzugsweise aus einem metallischen Material gebildet. Weitere Merkmale und Vorteile der Erfindung sind Gegenstand der nachfol genden Beschreibung und der zeichnerischen Darstellung von Ausführungsbei spielen. The flow field bipolar plate layer and / or the further bipolar plate layer of the bipolar plate are preferably formed from a metallic material. Further features and advantages of the invention are the subject of the following description and the graphic representation of Ausführungsbei play.
In den Zeichnungen zeigen: In the drawings show:
Fig. 1 eine ausschnittsweise schematische Draufsicht auf eine Bipolar platte für eine elektrochemische Vorrichtung, an welcher ein Strömungsfeld für ein fluides Medium ausgebildet ist; 1 shows a fragmentary schematic plan view of a bipolar plate for an electrochemical device, on which a flow field for a fluid medium is formed;
Fig. 2 einen Querschnitt durch die Bipolarplatte aus Fig. 1 und eine elektrochemisch aktive Einheit der elektrochemischen Vorrich tung, längs der Linie 2 - 2 in Fig. 1; FIG. 2 shows a cross section through the bipolar plate from FIG. 1 and an electrochemically active unit of the electrochemical device, along the line 2-2 in FIG. 1;
Fig. 3 eine ausschnittsweise schematische Draufsicht auf eine zweite Ausführungsform einer Bipolarplatte für eine elektrochemische Vorrichtung; und 3 shows a partial schematic plan view of a second embodiment of a bipolar plate for an electrochemical device; and
Fig. 4 einen Querschnitt durch die Bipolarplatte aus Fig. 3 und eine elektrochemisch aktive Einheit der elektrochemischen Vorrich tung, längs der Linie 4 - 4 in Fig. 3. 4 shows a cross section through the bipolar plate from FIG. 3 and an electrochemically active unit of the electrochemical device, along the line 4-4 in FIG. 3.
Gleiche oder funktional äquivalente Elemente sind in allen Figuren mit den selben Bezugszeichen bezeichnet. Identical or functionally equivalent elements are denoted by the same reference symbols in all figures.
Eine in den Fig. 1 und 2 ausschnittsweise dargestellte, als Ganzes mit 100 be- zeichnete elektrochemische Vorrichtung, beispielsweise ein Brennstoffzellen stapel oder ein Elektrolyseur, umfasst einen Stapel, der mehrere in einer Stapelrichtung 102 aufeinanderfolgende elektrochemische Einheiten 104, beispielsweise Brennstoffzelleneinheiten oder Elektrolyseeinheiten, und eine (nicht dargestellte) Spannvorrichtung zum Beaufschlagen der elektrochemi schen Einheiten 104 mit einer parallel zu der Stapelrichtung 102 gerichteten Spannkraft umfasst. An electrochemical device, shown in detail in FIGS. 1 and 2 and designated as a whole by 100, for example a fuel cell stack or an electrolyser, comprises a stack which contains several electrochemical units 104, one after the other in a stacking direction 102. for example fuel cell units or electrolysis units, and a tensioning device (not shown) for applying a tensioning force directed parallel to the stacking direction 102 to the electrochemical units 104.
Jede der elektrochemischen Einheiten 104 der elektrochemischen Vorrichtung 100 umfasst jeweils eine Bipolarplatte 106. Each of the electrochemical units 104 of the electrochemical device 100 each comprises a bipolar plate 106.
Jede Bipolarplatte 106 umfasst bei dieser Ausführungsform eine Strömungs- feld-Bipolarplattenlage 108, an welcher ein Strömungsfeld 110 für ein fluides Medium ausgebildet ist, und eine weitere Bipolarplattenlage 112, die fluiddicht, beispielsweise durch eine Schweißnahtanordnung, an der Strömungsfeld- Bipolarplattenlage 108 festgelegt ist. In this embodiment, each bipolar plate 106 comprises a flow field bipolar plate layer 108, on which a flow field 110 for a fluid medium is formed, and a further bipolar plate layer 112, which is fixed fluid-tight, for example by a weld seam arrangement, to the flow field bipolar plate layer 108.
Die Strömungsfeld-Bipolarplattenlage 108 weist Stege 114 und zwischen je weils zwei Stegen 114 liegende Kanalgrundabschnitte 116 auf. The flow field bipolar plate layer 108 has webs 114 and channel base sections 116 located between two webs 114 each.
Jeder der Stege 114 weist jeweils eine Kuppe 118 auf, mit welcher der Steg 114 an einer der Bipolarplatte 106 benachbarten elektrochemisch aktiven Ein heit 120 der elektrochemischen Vorrichtung 100 anliegt. Each of the webs 114 each has a dome 118 with which the web 114 rests against an electrochemically active unit 120 of the electrochemical device 100 adjacent to the bipolar plate 106.
Eine solche elektrochemisch aktive Einheit 120 kann insbesondere als eine Membran-Elektroden-Anordnung (MEA) 122 ausgebildet sein. Such an electrochemically active unit 120 can in particular be designed as a membrane electrode arrangement (MEA) 122.
Jede Kuppe 118 liegt mit einer Anlagefläche 124, welche im Wesentlichen senkrecht zur Stapelrichtung 102 ausgerichtet ist, im Wesentlichen flächig an einer der Bipolarplatte 106 zugewandten Begrenzungsfläche 126 der elektro chemisch aktiven Einheit 120, welche ebenfalls im Wesentlichen senkrecht zur Stapelrichtung 102 ausgerichtet ist, an. Each dome 118 rests with a contact surface 124, which is oriented essentially perpendicular to the stacking direction 102, essentially flat on a boundary surface 126 of the electrochemically active unit 120 facing the bipolar plate 106, which is also oriented essentially perpendicular to the stacking direction 102.
Ferner umfasst jeder Steg 114 zwei Flanken 128, welche gegenüber der Stapelrichtung 102 um einen spitzen Winkel geneigt sind. Zwischen den der jeweiligen Kuppe 118 abgewandten äußeren Rändern 130 von zwei einander benachbarten Stegen 114 erstreckt sich jeweils ein Kanal grundabschnitt 116 der Strömungsfeld-Bipolarplattenlage 108, welcher die beiden einander benachbarten Stege 114 miteinander verbindet. Furthermore, each web 114 comprises two flanks 128 which are inclined at an acute angle with respect to the stacking direction 102. A channel base section 116 of the flow field bipolar plate layer 108, which connects the two adjacent webs 114 to one another, extends between the outer edges 130 of two adjacent webs 114 facing away from the respective tip 118.
Jeder der Stege 114 erstreckt sich längs einer Steglängsrichtung 132, welche im Wesentlichen senkrecht zu der Stapelrichtung 102 ausgerichtet ist. Each of the webs 114 extends along a web longitudinal direction 132, which is oriented essentially perpendicular to the stacking direction 102.
Wie am besten aus Fig. 1 zu ersehen ist, endet jeder Steg 114 an seinen beiden Endbereichen 134 an jeweils einer Stirnwand 136, welche - ebenso wie die seitlichen Flanken 128 des jeweiligen Steges 114 - sowohl gegenüber der Kuppe 118 als auch gegenüber der Stapelrichtung 102 um einen spitzen Winkel geneigt sind. As can best be seen from FIG. 1, each web 114 ends at its two end regions 134 at a respective end wall 136, which - like the lateral flanks 128 of the respective web 114 - is opposite both to the dome 118 and to the stacking direction 102 are inclined at an acute angle.
Wie am besten aus Fig. 2 zu ersehen ist, begrenzen zwei einander benachbar te Stege 114 und der die beiden Stege 114 miteinander verbindende Kanal grundabschnitt 116 zusammen mit der elektrochemisch aktiven Einheit 120 jeweils einen Strömungsfeldkanal 138 des Strömungsfeldes 110. As can best be seen from FIG. 2, two adjacent webs 114 and the channel base section 116 connecting the two webs 114 together with the electrochemically active unit 120 each delimit a flow field channel 138 of the flow field 110.
Jeder Strömungsfeldkanal 138 des Strömungsfeldes 110 ist von dem fluiden Medium, welchem das Strömungsfeld 110 zugeordnet ist, längs einer Strö mungsrichtung 140 durchströmbar, welche innerhalb eines Strömungsfeld kanals 138 im Wesentlichen parallel zu den Steg-Längsrichtungen 132 der den betreffenden Strömungsfeldkanal 138 begrenzenden Stege 114 des Strö mungsfeldes 110 ausgerichtet ist. Each flow field channel 138 of the flow field 110 can be flowed through by the fluid medium to which the flow field 110 is assigned along a flow direction 140 which, within a flow field channel 138, is essentially parallel to the web longitudinal directions 132 of the webs 114 delimiting the relevant flow field channel 138 Strö flow field 110 is aligned.
Die Strömungsfeldkanäle 138 des Strömungsfeldes 110 münden an ihrem stromaufwärts liegenden Ende in einen Medium-Zuführbereich 142 des Strö mungsfeldes 110 und an ihrem stromabwärts liegenden Ende in einen Medium-Abführbereich 144 des Strömungsfeldes 110. Im Betrieb der elektrochemischen Vorrichtung 100 tritt das fluide Medium, welchem das Strömungsfeld 110 zugeordnet ist, durch einen (vorzugsweise im Wesentlichen parallel zur Stapelrichtung 102 verlaufenden, nicht dargestell ten) Medium-Zuführkanal in den Medium-Zuführbereich 142 des Strömungs feldes 110 ein, von wo es auf die verschiedenen Strömungsfeldkanäle 138 ver teilt wird und dieselben längs der Strömungsrichtung 140 durchströmt. The flow field channels 138 of the flow field 110 open at their upstream end into a medium supply area 142 of the flow field 110 and at their downstream end into a medium discharge area 144 of the flow field 110. During operation of the electrochemical device 100, the fluid medium, to which the flow field 110 is assigned, enters the medium supply region 142 of the flow field 110 through a medium supply channel (not shown, which preferably runs essentially parallel to the stacking direction 102) where it is divided into the various flow field channels 138 ver and flows through the same along the flow direction 140.
Das fluide Medium kann insbesondere ein Anodengas oder ein Kathodengas für die elektrochemische Vorrichtung 100 sein. The fluid medium can in particular be an anode gas or a cathode gas for the electrochemical device 100.
Das fluide Medium gelangt aus den Strömungsfeldkanälen 138 zu der elektro chemisch aktiven Einheit 120, wo die jeweils elektrochemisch aktive Spezies aus dem fluiden Medium im Zuge der in der elektrochemisch aktiven Einheit 120 ablaufenden elektrochemischen Reaktionen verbraucht wird, so dass die Konzentration der elektrochemisch aktiven Spezies in dem die Strömungsfeld kanäle 138 durchströmenden fluiden Medium längs der Strömungsrichtung 140 abnimmt. The fluid medium passes from the flow field channels 138 to the electrochemically active unit 120, where the respective electrochemically active species from the fluid medium is consumed in the course of the electrochemical reactions taking place in the electrochemically active unit 120, so that the concentration of the electrochemically active species in the fluid medium flowing through the flow field channels 138 decreases along the flow direction 140.
Um diese Abnahme zumindest in einem Teil des Strömungsfeldes 110 zumin dest teilweise auszugleichen, umfasst die Bipolarplatte 106 mindestens einen Bypasskanal 146 für das fluide Medium, welchem des Strömungsfeld 110 zu geordnet ist. In order to at least partially compensate for this decrease in at least a part of the flow field 110, the bipolar plate 106 comprises at least one bypass channel 146 for the fluid medium to which the flow field 110 is assigned.
Der Bypasskanal 146 ist durch einen Steg 114a und einen dem Steg 114a ge genüberliegenden Steg 114a', welcher in der weiteren Bipolarplattenlage 112 ausgebildet ist, begrenzt (siehe Fig. 2). Der Steg 114a' weist ebenfalls eine Kuppe 118' mit einer im Wesentlichen senkrecht zur Stapelrichtung 102 aus gerichteten Anlagefläche 124' und zwei gegenüber der Stapelrichtung 102 um einen spitzen Winkel geneigte Flanken 128' auf. Die Strömungsfeld-Bipolarplattenlage 108 und die weitere Bipolarplattenlage 112 sind längs einer oder mehreren den Bypasskanal 146 berandenden Füge linien 148 fluiddicht miteinander verbunden. The bypass channel 146 is delimited by a web 114a and a web 114a 'opposite the web 114a, which web is formed in the further bipolar plate layer 112 (see FIG. 2). The web 114a 'likewise has a dome 118' with a contact surface 124 'oriented essentially perpendicular to the stacking direction 102 and two flanks 128' inclined at an acute angle relative to the stacking direction 102. The flow field bipolar plate layer 108 and the further bipolar plate layer 112 are connected to one another in a fluid-tight manner along one or more joining lines 148 bordering the bypass channel 146.
Grundsätzlich kommt jedes stoffschlüssige Fügeverfahren für die Herstellung der mindestens einen Fügelinie 148 in Betracht. In principle, every material joining method can be used to produce the at least one joining line 148.
Insbesondere kann vorgesehen sein, dass die Fügelinie 148 eine Lötlinie oder eine Schweißlinie 150 ist. In particular, it can be provided that the joining line 148 is a soldering line or a welding line 150.
Eine Schweißlinie 150 kann insbesondere durch einen Laserschweißvorgang an der Bipolarplatte 106 erzeugt sein. A weld line 150 can in particular be produced on the bipolar plate 106 by a laser welding process.
Zwischen der Strömungsfeld-Bipolarplattenlage 108 und der weiteren Bipolar plattenlage 112 ist neben dem Bypasskanal 146 ein Fluidkanal 152 für ein weiteres fluides Medium ausgebildet. In addition to the bypass channel 146, a fluid channel 152 for a further fluid medium is formed between the flow field bipolar plate layer 108 and the further bipolar plate layer 112.
Dieses weitere fluide Medium ist von dem fluiden Medium, welchem das Strö mungsfeld 110 zugeordnet ist, verschieden. This further fluid medium is different from the fluid medium to which the flow field 110 is assigned.
Das weitere fluide Medium kann insbesondere ein Kühlmedium zum Kühlen der elektrochemischen Vorrichtung 100 sein. The further fluid medium can in particular be a cooling medium for cooling the electrochemical device 100.
Der Fluidkanal 152, der von dem weiteren fluiden Medium durchströmbar ist, ist von dem Bypasskanal 146 durch eine der im Wesentlichen fluiddichten Fügelinien 148 getrennt. The fluid channel 152, through which the further fluid medium can flow, is separated from the bypass channel 146 by one of the essentially fluid-tight joining lines 148.
Ferner ist der von dem weiteren fluiden Medium durchströmbare Fluidkanal 152 gegenüber der elektrochemisch aktiven Einheit 120 geschlossen ausge bildet, so dass das weitere fluide Medium, insbesondere das Kühlmedium, nicht aus dem Fluidkanal 152 in die elektrochemisch aktive Einheit 120 gelangen kann. Wie am besten aus Fig. 1 zu ersehen ist, umfasst der Bypasskanal 146 einen Bypass- Eintritt 154, durch welchen das fluide Medium, welchem das Strö mungsfeld 110 zugeordnet ist, in den Bypasskanal 146 eintreten kann, und einen stromabwärts von dem Bypass-Eintritt 154 angeordneten Bypass-Aus tritt 156, durch welchen das fluide Medium aus dem Bypasskanal 146 in den angrenzenden Strömungsfeldkanal 138a austreten kann. Furthermore, the fluid channel 152 through which the further fluid medium can flow is designed to be closed with respect to the electrochemically active unit 120, so that the further fluid medium, in particular the cooling medium, cannot pass from the fluid channel 152 into the electrochemically active unit 120. As can best be seen from FIG. 1, the bypass channel 146 comprises a bypass inlet 154 through which the fluid medium to which the flow field 110 is assigned can enter the bypass channel 146, and one downstream of the bypass inlet 154 arranged bypass outlet exits 156, through which the fluid medium can exit from the bypass channel 146 into the adjacent flow field channel 138a.
Der Bypass-Eintritt 154 ist beispielsweise als eine Durchtrittsöffnung in der Stirnwand 136a des Steges 114a, welche im stromaufwärts liegenden Endbe reich 134 des Steges 114a angeordnet ist, ausgebildet. The bypass inlet 154 is formed, for example, as a passage opening in the end wall 136a of the web 114a, which is arranged in the upstream end region 134 of the web 114a.
Der Bypass-Austritt 156 ist beispielsweise als eine Durchtrittsöffnung in der dem Strömungsfeldkanal 138a zugewandten Flanke 128a des Steges 114a ausgebildet. The bypass outlet 156 is designed, for example, as a passage opening in the flank 128a of the web 114a facing the flow field channel 138a.
Zwischen dem stromaufwärts liegenden Bypass- Eintritt 154 und dem strom abwärts liegenden Bypass-Austritt 156 liegt ein Strömungsfeldkanalabschnitt 158 des Strömungsfeldkanals 138a, welcher mittels des Bypasskanals 146 umgangen wird, so dass der Anteil des fluiden Mediums, welcher durch den Bypass-Eintritt 154 in den Bypasskanal 146 eintritt und aus dem Bypass- Austritt 156 wieder aus dem Bypasskanal 146 in den Strömungsfeldkanal 138a austritt, nicht den Strömungsfeldkanalabschnitt 158 durchströmt und somit nicht aus dem Strömungsfeldkanalabschnitt 158 zu der elektrochemisch aktiven Einheit 120 gelingen kann. Between the upstream bypass inlet 154 and the downstream bypass outlet 156 is a flow field channel section 158 of the flow field channel 138a, which is bypassed by means of the bypass channel 146, so that the portion of the fluid medium which passes through the bypass inlet 154 into the Bypass channel 146 enters and exits from bypass outlet 156 again from bypass channel 146 into flow field channel 138a, does not flow through flow field channel section 158 and thus cannot get out of flow field channel section 158 to electrochemically active unit 120.
Der durch den Bypasskanal 146 strömende Anteil des fluiden Mediums kann auch nicht aus dem Bypasskanal 146 in die elektrochemisch aktive Einheit 120 gelangen, weil der Bypasskanal 146 gegenüber der elektrochemisch aktiven Einheit 120 geschlossen ausgebildet ist. Die Konzentration der elektrochemisch aktiven Spezies in dem fluiden Medium bleibt daher in dem den Bypasskanal 146 durchströmenden Anteil des fluiden Mediums erhalten, so dass durch die Zufuhr dieses Anteils des fluiden Me diums aus dem Bypasskanal 146 durch den Bypass-Austritt 156 in den strom abwärts von dem Strömungsfeldkanalabschnitt 158 liegenden Teil des Strö mungsfeldkanals 138a die Verringerung der Konzentration der elektroche misch aktiven Spezies in dem den Strömungsfeldkanal 138a durchströmenden fluiden Medium zumindest teilweise ausgeglichen wird. The portion of the fluid medium flowing through the bypass channel 146 cannot pass from the bypass channel 146 into the electrochemically active unit 120 either, because the bypass channel 146 is designed to be closed with respect to the electrochemically active unit 120. The concentration of the electrochemically active species in the fluid medium therefore remains in the portion of the fluid medium flowing through the bypass channel 146, so that by supplying this portion of the fluid medium from the bypass channel 146 through the bypass outlet 156 into the downstream of the part of the flow field channel 138a lying in the flow field channel section 158, the reduction in the concentration of the electrochemically active species in the fluid medium flowing through the flow field channel 138a is at least partially compensated for.
Eine in den Fig. 3 und 4 dargestellte zweite Ausführungsform einer elektro chemischen Vorrichtung 108, die eine Bipolarplatte 106 umfasst, welche ihrerseits einen Bypasskanal 146 für ein fluides Medium umfasst, unterschei det sich von der in den Fig. 1 und 2 dargestellten ersten Ausführungsform dadurch, dass der Bypass-Austritt 156 des Bypasskanals 146 nicht in einer dem Strömungsfeldkanal 138a zugewandten Flanke 128a des Steges 114a ausgebildet ist, sondern in der Kuppe 118 des Steges 114a, so dass der durch den Bypasskanal 146 strömende Anteil des fluiden Mediums, welchem das Strömungsfeld 110 zugeordnet ist, bei dieser Ausführungsform direkt der elektrochemisch aktiven Einheit 120 zugeführt wird. A second embodiment of an electrochemical device 108 shown in FIGS. 3 and 4, which comprises a bipolar plate 106, which in turn includes a bypass channel 146 for a fluid medium, differs from the first embodiment shown in FIGS. 1 and 2 in this way that the bypass outlet 156 of the bypass channel 146 is not formed in a flank 128a of the web 114a facing the flow field channel 138a, but in the dome 118 of the web 114a, so that the portion of the fluid medium flowing through the bypass channel 146 which the flow field 110 is assigned, is fed directly to the electrochemically active unit 120 in this embodiment.
Im Übrigen stimmt die in den Fig. 3 und 4 dargestellte zweite Ausführungs form einer elektrochemischen Vorrichtung 100 hinsichtlich Aufbau, Herstellung und Funktionsweise mit der in den Fig. 1 und 2 dargestellten ersten Ausfüh rungsform überein, auf deren vorstehende Beschreibung insoweit Bezug ge nommen wird. Otherwise, the second embodiment shown in FIGS. 3 and 4 of an electrochemical device 100 in terms of structure, manufacture and mode of operation corresponds to the first embodiment shown in FIGS.

Claims

Patentansprüche Claims
1. Bipolarplatte für eine elektrochemische Vorrichtung (100), umfassend eine Strömungsfeld-Bipolarplattenlage (108), an welcher ein Strömungs feld (110) für ein fluides Medium ausgebildet ist, wobei das Strömungsfeld (110) einen Strömungsfeldkanal (138a) um fasst, welcher von dem fluiden Medium längs einer Strömungsrichtung (140) durchströmbar ist und welcher einen Strömungsfeldkanalabschnitt (158) für das fluide Medium umfasst, der im montierten Zustand der Bi polarplatte (106) zu einer elektrochemisch aktiven Einheit (120) der elektrochemischen Vorrichtung (100) hin offen ist, d a d u r c h g e k e n n z e i c h n e t, dass die Bipolarplatte (106) einen Bypasskanal (146) für das fluide Me dium umfasst, wobei der Bypasskanal (146) einen stromaufwärts von dem Strömungs feldkanalabschnitt (158) angeordneten Bypass- Eintritt (154), durch welchen das fluide Medium in den Bypasskanal (146) eintreten kann, und einen stromabwärts von dem Strömungsfeldkanalabschnitt (158) ange ordneten Bypass-Austritt (156), durch welchen das fluide Medium aus dem Bypasskanal (146) in den Strömungsfeldkanal (138a) austreten kann, umfasst, und wobei der Bypasskanal (146) gegenüber der elektrochemisch aktiven Einheit (120) geschlossen ausgebildet ist. 1. Bipolar plate for an electrochemical device (100), comprising a flow field bipolar plate layer (108) on which a flow field (110) for a fluid medium is formed, the flow field (110) comprising a flow field channel (138a) which the fluid medium can flow through it along a flow direction (140) and which comprises a flow field channel section (158) for the fluid medium which, in the assembled state of the bi-polar plate (106), leads to an electrochemically active unit (120) of the electrochemical device (100) is open, characterized in that the bipolar plate (106) comprises a bypass channel (146) for the fluid medium, the bypass channel (146) having a bypass inlet (154) arranged upstream of the flow field channel section (158) through which the fluid Medium can enter the bypass channel (146), and a downstream of the flow field channel section (158) is arranged bypass Outlet (156) through which the fluid medium can exit from the bypass channel (146) into the flow field channel (138a), and wherein the bypass channel (146) is designed to be closed with respect to the electrochemically active unit (120).
2. Bipolarplatte nach Anspruch 1, dadurch gekennzeichnet, dass der By passkanal (146) durch die Strömungsfeld-Bipolarplattenlage (108), an welcher das Strömungsfeld (110) für das fluide Medium ausgebildet ist, und durch eine weitere Bipolarplattenlage (112) der Bipolarplatte (106) begrenzt ist. 2. Bipolar plate according to claim 1, characterized in that the by pass channel (146) through the flow field bipolar plate layer (108), on which the flow field (110) is formed for the fluid medium, and by a further bipolar plate layer (112) of the bipolar plate (106) is limited.
3. Bipolarplatte nach Anspruch 2, dadurch gekennzeichnet, dass die Strö- mungsfeld-Bipolarplattenlage (108) und die weitere Bipolarplattenlage (112) längs einer den Bypasskanal (146) berandenden Fügelinie (148) im Wesentlichen fluiddicht miteinander verbunden sind. 3. Bipolar plate according to claim 2, characterized in that the flow field bipolar plate layer (108) and the further bipolar plate layer (112) are connected to one another in a substantially fluid-tight manner along a joining line (148) bordering the bypass channel (146).
4. Bipolarplatte nach Anspruch 3, dadurch gekennzeichnet, dass die Füge linie (148) eine Lötlinie oder eine Schweißlinie (115) ist. 4. Bipolar plate according to claim 3, characterized in that the joining line (148) is a soldering line or a welding line (115).
5. Bipolarplatte nach einem der Ansprüche 2 bis 4, dadurch gekennzeich net, dass zwischen der Strömungsfeld-Bipolarplattenlage (108) und der weiteren Bipolarplattenlage (112) ein Fluidkanal (152) für ein weiteres fluides Medium ausgebildet ist. 5. Bipolar plate according to one of claims 2 to 4, characterized in that a fluid channel (152) for a further fluid medium is formed between the flow field bipolar plate layer (108) and the further bipolar plate layer (112).
6. Bipolarplatte nach Anspruch 5, dadurch gekennzeichnet, dass der By passkanal (146) von dem Fluidkanal (152) durch eine im Wesentlichen fluiddichte Fügelinie (148) getrennt ist. 6. Bipolar plate according to claim 5, characterized in that the by pass channel (146) is separated from the fluid channel (152) by a substantially fluid-tight joining line (148).
7. Bipolarplatte nach einem der Ansprüche 5 oder 6, dadurch gekennzeich net, dass der Fluidkanal (152) gegenüber der elektrochemisch aktiven Einheit (120) geschlossen ausgebildet ist. 7. Bipolar plate according to one of claims 5 or 6, characterized in that the fluid channel (152) is designed to be closed with respect to the electrochemically active unit (120).
8. Bipolarplatte nach einem der Ansprüche 5 bis 7, dadurch gekennzeich net, dass das weitere fluide Medium ein Kühlmedium ist. 8. Bipolar plate according to one of claims 5 to 7, characterized in that the further fluid medium is a cooling medium.
9. Bipolarplatte nach einem der Ansprüche 1 bis 8, dadurch gekennzeich net, dass das fluide Medium ein Anodengas oder ein Kathodengas für die elektrochemische Vorrichtung (100) ist. 9. Bipolar plate according to one of claims 1 to 8, characterized in that the fluid medium is an anode gas or a cathode gas for the electrochemical device (100).
10. Bipolarplatte nach einem der Ansprüche 1 bis 9, dadurch gekennzeich net, dass der Bypasskanal (146) durch einen Steg (114a) des Strö mungsfeldes (110), weicher einen Strömungsfeldkanal (138a) des Strömungsfeldes (110) seitlich begrenzt, begrenzt ist. 10. Bipolar plate according to one of claims 1 to 9, characterized in that the bypass channel (146) is laterally bounded by a web (114a) of the flow field (110), which is a flow field channel (138a) of the flow field (110) .
11. Bipolarplatte nach Anspruch 10, dadurch gekennzeichnet, dass der By pass-Austritt (156) an einer Flanke (128a) des Steges (114a) angeord net ist. 11. Bipolar plate according to claim 10, characterized in that the by-pass outlet (156) on a flank (128a) of the web (114a) is angeord net.
12. Bipolarplatte nach Anspruch 10, dadurch gekennzeichnet, dass der By pass-Austritt (156) an einer Kuppe (118) des Steges (114a) angeordnet ist. 12. Bipolar plate according to claim 10, characterized in that the by-pass outlet (156) is arranged on a tip (118) of the web (114a).
13. Bipolarplatte nach einem der Ansprüche 10 bis 12, dadurch gekenn zeichnet, dass der Bypass-Eintritt (154) an einer Stirnwand (136) des Steges (114a) angeordnet ist. 13. Bipolar plate according to one of claims 10 to 12, characterized in that the bypass inlet (154) is arranged on an end wall (136) of the web (114a).
14. Bipolarplatte nach einem der Ansprüche 10 bis 13, dadurch gekenn zeichnet, dass das Strömungsfeld (110) mehrere parallel zueinander von dem fluiden Medium durchströmbare Strömungsfeldkanäle (138, 138a) umfasst. 14. Bipolar plate according to one of claims 10 to 13, characterized in that the flow field (110) comprises a plurality of flow field channels (138, 138a) through which the fluid medium can flow parallel to one another.
15. Elektrochemische Vorrichtung, umfassend mindestens eine elektroche misch aktive Einheit (120) und mindestens eine Bipolarplatte (106) nach einem der Ansprüche 1 bis 14, deren Strömungsfeldkanalabschnitt (158) zu der elektrochemisch aktiven Einheit (120) hin offen ist. 15. An electrochemical device comprising at least one electrochemically active unit (120) and at least one bipolar plate (106) according to one of claims 1 to 14, the flow field channel section (158) of which is open to the electrochemically active unit (120).
PCT/EP2021/058171 2020-03-31 2021-03-29 Bipolar plate for an electrochemical device, and electrochemical device WO2021198184A1 (en)

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Citations (3)

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US20100136452A1 (en) * 2007-07-18 2010-06-03 Mads Bang Bipolar plate for a fuel cell comprising a by-passed serpentine flow path for oxidant gas; a cooling plate for a fuel cell comprising a by-passed serpentine flow path for coolant fluid; fuel cell comprising such plates and uses thereof
US20150132677A1 (en) * 2012-06-11 2015-05-14 Htceramix S.A. Solid oxide fuel cell
US20180048012A1 (en) * 2016-08-10 2018-02-15 GM Global Technology Operations LLC Fuel cell stack assembly

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KR102371604B1 (en) 2017-05-26 2022-03-07 현대자동차주식회사 Fuel cell stack

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100136452A1 (en) * 2007-07-18 2010-06-03 Mads Bang Bipolar plate for a fuel cell comprising a by-passed serpentine flow path for oxidant gas; a cooling plate for a fuel cell comprising a by-passed serpentine flow path for coolant fluid; fuel cell comprising such plates and uses thereof
US20150132677A1 (en) * 2012-06-11 2015-05-14 Htceramix S.A. Solid oxide fuel cell
US20180048012A1 (en) * 2016-08-10 2018-02-15 GM Global Technology Operations LLC Fuel cell stack assembly

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