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
  • H01M8/0204—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
  • H01M8/0247—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
• • 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
  • H01M8/026—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant characterised by grooves, e.g. their pitch or depth
• • 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
  • H01M8/0263—Collectors; Separators, e.g. bipolar separators; Interconnectors characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant having meandering or serpentine paths
• • 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
• • 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

• FLOW ELEMENT USE OF A FLOW ELEMENT, BIPOLAR PLATE AND METHOD OF MANUFACTURING A FLOW ELEMENT
• the present invention relates to a flow element, in particular as a component of a bipolar plate of an electrochemical device, for example a fuel cell device.
• the present invention relates to a use of a flow element, a bipolar plate with at least one flow element and a method for producing a flow element.
• the object of the present invention is to provide a flow element that has a robust design and advantageous flow properties.
• a flow element according to the invention in particular as a component of a bipolar plate of an electrochemical device, comprising a plate-shaped base body which extends in two main directions of extent aligned at an angle to one another and in a height direction aligned transversely and in particular perpendicular thereto, the The base body has a channel structure with a plurality of channels which are arranged laterally next to one another, the channels being formed by depressions in the base body and being separated from one another by elevations of the base body arranged between the depressions, with areas with a
• the defined normal level difference is provided as a height difference between an elevation and an adjacent depression, as well as areas with a level difference that is reduced in relation to the normal level difference as a height difference between an elevation and an adjacent depression, with areas with normal level differences and areas with repeating at least in sections in the direction of the channels Reduced level difference are provided and areas with reduced level difference of adjacent channels are shifted relative to their respective direction of course against one another, the areas with reduced level difference being formed by
• a saddle area can be formed in particular in the direction of a canal by a rising canal bottom and thus a reduced level difference compared to the valley area, and transversely to be limited by rising flanks of the elevations that separate the canal from adjacent Kanä sources.
• the saddle areas and valley areas are created within the respective channel, preferably pressure fluctuations of the dynamic and / or static pressure of the flowing fluid. Such pressure fluctuations preferably take place in the neighboring channels.
• a respective valley area of an adjacent canal lies opposite the Saddle Elbe. This can in particular be understood to mean that, starting from the saddle area, a valley area is provided transversely and in particular perpendicular to the direction of the canal after crossing the elevation separating the canals.
• GDL porous gas diffusion layer
• the channels are used to supply a reaction fluid, for example air or hydrogen gas
• a reaction fluid for example air or hydrogen gas
• an effective supply of reaction gas can advantageously also be ensured in the area of the GDL.
• a pressure loss within the respective channel can be kept low via the type of design of the areas with reduced level difference by means of saddle areas.
• a respective channel has at least sections repeating saddle areas and valley areas. Such a design can be provided over the entire length of a channel. To simplify understanding of the invention and to facilitate readability, it is assumed below that such a configuration is present over at least a section of a respective channel, even if this is not mentioned in detail in each case.
• a course direction of the channel defines in particular a flow direction through the channel.
• the saddle areas and valley areas of respectively adjacent channels are preferably arranged “in a gap” in such a way that a respective valley area of an adjacent channel lies opposite a respective saddle area.
• Saddle areas and valley areas are formed in opposite directions in neighboring canals, whereby he can give particularly advantageous overflows on the increases.
• a modulation of a cross-sectional area of the respective channel through which a flow can flow is preferably formed.
• the channel can be formed in particular with a depth modulation and as a result of its cross-sectional modulation.
• the saddle areas can be configured, for example, as convex areas of the base body in which the base body "protrudes” in the direction of view of the channels.
• the valley areas can be designed, for example, as concave areas of the base body, in which the base body “recedes” in the direction of view of the channels.
• a curvature of the Grundkör pers in the direction of the channel is less than transversely and in particular perpendicular to the direction, in particular at an apex of the saddle area, in the saddle areas.
• the curvature of the Grundkör pers due to the saddle-shaped elevation of the channel bottom is preferably less ger than transversely to the direction where the channel bottom merges into the flanks of the elevations.
• the amount of change in the channel depth along the course direction due to the saddle areas and the valley areas or the amount of change in the channel depth transversely to the course direction due to the elevations between the channels is viewed as curvature.
• a sign of the curvature results from the direction of the formation of the Grundkör pers, especially in the valley area upwards ("positive") and in the saddle area rich downwards ("negative”).
• a curvature resulting from a change in the channel depth can be discrete or continuous, for example.
• the saddle area and / or the valley area can have straight sections adjoining each other at an angle (similar to a polygon).
• the apex of the saddle area and / or a valley bottom of the saddle area can be uncurved, but the saddle area and / or the valley area in its overall extent result from a curvature of the base body.
• a curvature of the base body in the direction of the passage of the channel is the same size or essentially the same size at the saddle areas and at the valley areas.
• the direction of curvature can, however, have different signs at the valley areas and at the saddle areas.
• the base body can be curved upwards at the valley areas and downwards at the saddle areas.
• a curvature of the base body in the direction of the channel is less than transverse and in particular perpendicular to the direction of the path, in particular at a valley floor of the valley area.
• the base body can have a less pronounced curvature than transverse to it, where the valley floor merges into the flanks of the elevations.
• valley areas and the saddle areas are formed in a periodically repeating manner within a respective channel.
• particularly advantageous flow properties can be given to the flow element in that static and / or dynamic pressure variations can be periodically repeated.
• a period length of the repetition of the valley areas and the saddle areas of the channels can be the same size or essentially the same size. In the present case, this can in particular be understood to mean that the channels have identical or essentially identical period lengths.
• valley areas and saddle areas of adjacent canals can be positioned “on a gap”, so to speak.
• the base body has saddle areas and valley areas in a regular arrangement, in particular based on a plan view of the base body along the height direction.
• a period length of the period of the saddle areas and valley areas is advantageously approximately 2 mm to 50 mm, preferably approximately 4 mm to 20 mm.
• a length of a respective saddle area in the channel direction can preferably be approximately 1 mm to 25 mm, advantageously approximately 2 mm to 10 mm. The same can favorably apply to a respective valley area.
• the saddle areas and / or the valley areas are designed to be planar in sections.
• the saddle area has a planar apex and / or the valley area has a planar valley bottom.
• the saddle areas and / or the valley areas can be implemented by canal sections that are continuously curved in the direction of the canal.
• essentially sinusoidal saddle areas and / or valley areas are provided. It can be provided that the saddle areas and the valley areas merge into one another in the course of the canal or directly border one another.
• the saddle areas and / or the valley areas can each be formed symmetrically, in particular in relation to a canal center plane and / or in relation to a canal transverse plane oriented transversely and in particular perpendicular to the direction of the canal.
• the saddle areas and / or the valley areas are configured asymmetrically with respect to the channel center plane and / or the channel transverse plane.
• An angle of incidence of a saddle area with respect to a reference plane formed by the valley areas can in particular be approximately 2 ° to 60 °, preferably approximately 2 ° to 40 °.
• the angle of attack can be understood to mean in particular an angle of a slope of the saddle area that rises or falls in the direction of the course of the channel, via which slope the saddle area can be connected to a valley area or borders on it.
• a material thickness of the base body in particular in the case of a formed part before the forming, can be, for example, approximately 40 ⁇ m to approximately 500 ⁇ m, preferably approximately 50 ⁇ m to 120 ⁇ m.
• the depth of the channels in an area with a normal level difference and / or in an area with a reduced level difference is dependent on a material thickness of the base body.
• dimensions that relate to the channels are preferably given as clear information without taking into account a material thickness of the base body.
• a depth of the channels at an area with a normal level difference can preferably be approximately from 0.15 mm to 1.0 mm, preferably approximately from 0.2 mm to 0.6 mm.
• a ratio of the material thickness of the base body to the depth of the channels can be, for example, approximately from 0.05 to 0.8, preferably approximately from 0.15 to 0.4, in the latter case.
• a depth of the channels can preferably be approximately from 0.05 mm to 0.6 mm, preferably approximately from 0.1 mm to 0.5 mm.
• a ratio of the material thickness of the base body to the depth of the channels can preferably be approximately from 0.05 to 3, preferably approximately from 0.1 to 1.2.
• a ratio of the depth of the channels at an area with a reduced level difference to the depth at an area with a normal level difference is approximately 0.1 to 0.9, preferably approximately 0.3 to 0.7.
• the channels repeatedly have narrowing regions in their direction of extension, at which a width of the channels transversely and in particular perpendicular to the direction of extension is smaller than in normal width regions arranged between the narrowing regions.
• a width of the respective channel can, for example, be measured approximately halfway up the flank of the elevations delimiting the channel. Since the height of the flanks of the elevations varies between the saddle areas and the valley areas, it can alternatively be provided that a width of the channel is measured in a plane which, for example, is aligned parallel to a plane that extends from a contact plane of the base body or from the valley areas is defined and the value of half a depth of the area with normal level difference is spaced from this level.
• the channels repeatedly have normal width areas and widening areas in their direction of extension.
• the narrowing areas can correspond to the normal width areas and the normal width areas can correspond to the widening areas.
• a flow element comprising a plate-shaped base body which extends in two main directions of extent oriented at an angle to one another and has an extension in a height direction oriented transversely and in particular perpendicular thereto
• the base body having a channel structure with a plurality of channels arranged laterally next to one another are, wherein the channels are formed by depressions in the base body and are separated from each other by angeord designated elevations of the base body between the depressions, it can be provided that the channels in the direction of which they extend have repeatedly narrowing areas, where a width of the channels transversely and in particular perpendicular to the direction of extension is less than at the normal width areas arranged between the narrowing areas.
• Such a flow element can define an independent invention and optionally include further features disclosed here alone or in combination with one another, in particular areas with normal level difference and areas with reduced level difference can be provided.
• the narrowing areas are advantageously cross-sectional reduction areas at which a cross-sectional area of the channels through which a flow can flow is reduced in relation to that of the normal width areas. This gives the Ability to modulate the channel width. In this way, modulations of the static and / or dynamic pressure in the channels can be achieved. This can cause pressure fluctuations between adjacent channels in order to enable an overflow between adjacent channels.
• a respective normal width area of an adjacent channel lies opposite the narrowing areas. This favors the overflow of the fluid over the elevations to the adjacent channel.
• the narrowing areas, in the direction of the channels are arranged or formed on the saddle areas and the normal width areas are arranged or formed in the valley areas. In this way, a particularly effective modulation of the free cross-sectional area of a respective channel can be achieved.
• the canals are less deep and narrower, while in the valley areas they are deeper and wider.
• the respective adjacent channels have saddle areas, valley areas, narrowing areas and normal width areas that are shifted with respect to that of the first-mentioned channel and, in particular, are shifted by half a period length.
• modulations of the static and / or dynamic pressure can be achieved with a view to an improved overflow via the elevation.
• flanks of the elevations at the narrowing areas run towards one another and then run away from one another.
• Consstrictions of the channels can accordingly be provided at the narrowing areas.
• flanks of the elevations in the direction of the channels, are separated from one another in the normal width areas. run away and then run towards each other. Accordingly, “widenings” can be provided in the normal width areas.
• the extent of the narrowing areas and the normal width areas in the direction of the channel can preferably be the same size or essentially the same size.
• the narrowing areas and the normal width areas are preferably formed in a periodically repeating manner.
• a period length of the repetition of the narrowing areas and the normal width areas of the channels is advantageously the same size or essentially the same size.
• this can in particular be understood to mean that the channels have identical period lengths for the narrowing areas and the normal width areas, just as this preferably applies to the saddle areas and the valley areas.
• a course line of the flanks of the narrowing areas and the normal width areas in a plan view of the base body along the height direction can be different.
• the course line is sinusoidal, zigzag or in the form of juxtaposed circular arcs.
• the narrowing areas and the normal width areas merge into one another in the course of the canal or directly adjoin one another.
• the narrowing areas and / or the normal width areas are inherently symmetrical with respect to a channel center plane.
• the narrowing areas and / or the normal width areas are inherently symmetrical with respect to a transverse channel plane perpendicular to the direction in which the channels run.
• a width of the channel at the narrowing area measured in particular at half the height of a flank of the elevation, can for example be approximately from 0.2 mm to 2 mm, preferably approximately from 0.3 mm to 1 mm.
• a ratio of the material thickness of the base body to the width of the channels is preferably approximately from 0.05 to 0.5, preferably approximately from 0.1 to 0.3.
• a width of the channel in the normal width area, measured in particular at half the height of a flank of the elevation, is, for example, approximately from 0.3 mm to 3 mm, preferably approximately from 0.4 mm to 2 mm.
• a ratio of the material thickness of the base body to the width of the channels is preferably approximately from 0.05 to 1.25, preferably approximately from 0.1 to 1.0.
• a ratio of a width of the channels in a narrowing region to a width in a normal width region is preferably approximately from 0.1 to 1.0, preferably approximately 0.4 to 0.85.
• a width of the elevations is, for example, approximately from 0.2 mm to 1.5 mm, preferably approximately 0.3 mm to 0.8 mm.
• a ratio of the material thickness of the base body to the width of the channels is preferably approximately from 0.05 to 0.7, preferably approximately from 0.1 to 0.4.
• the areas with cross-sectional enlargement and cross-sectional reduction are provided in a periodically repeating manner on the respective channel.
• the elevations in the areas with a widened cross-section and in the areas with a reduced cross-section have different widths transversely and, in particular, perpendicular to the direction in which the channel extends.
• Areas with enlarged cross-section and areas with reduced cross-section are preferably configured asymmetrically relative to one another.
• the extent of the areas with a reduction in cross section is preferably less than the extent of the areas with an enlarged cross section, in particular in order to achieve the aforementioned asymmetry.
• a channel can be reduced at a reduction angle in an area with a reduction in cross section.
• the opening angle and / or the reduction angle can in particular have legs extending along flanks of the elevations that delimit the channel.
• the reduction angle can be greater than the opening angle.
• the opening angle can be, for example, approximately from 0.5 ° to 20 °, preferably approximately 1 ° to 5 °.
• the reduction angle can be, for example, approximately from 0.5 ° to 20 °, preferably approximately 1 ° to 10 °.
• the elevations form contact elements of the base body for contact in particular with a gas diffusion layer (GDL) of an electrochemical device.
• GDL gas diffusion layer
• the system elements can define a system side or top of the flow element, for example.
• the gas diffusion layer can reliably rest on the base body via the contact elements.
• the contact elements are preferably each designed in a planar manner in order to enable a flat contact.
• the contact elements can form or define a common contact plane.
• the contact elements are arranged in an imaginary curved surface.
• the base body can have a relatively large radius which can coincide with a radius of a gas diffusion layer.
• the contact elements in the direction of the channels, have a zigzag shape.
• a zigzag course can result, for example, as a result of a width modulation of the channels as explained above, in which narrowing areas and normal widths or areas with cross-sectional expansion and cross-sectional reduction are provided.
• Elevations of the base body can advantageously have a zigzag shape in the course of the channel, in particular with regard to a zigzag course of the contact elements.
• the width of the above-mentioned overlap area can, for example, be adjustable or set across the width of the elevations transversely to the direction of extension of the channels and / or a modulation amplitude of channel widening and narrowing.
• the elevations can have the same or essentially the same width transversely and in particular perpendicular to the direction of extension of the respective channel, over the direction of extension of the channel.
• the elevations transversely and in particular perpendicular to the direction of the channel, over the direction of the channel have a different width.
• the channels can be designed at least in sections symmetrically with respect to a channel center plane which is aligned in particular perpendicular to a plane defined by the abovementioned contact elements.
• channels are formed asymmetrically with respect to a channel center plane or channel center line.
• a channel center line can be curved.
• a modulation width in the case of a cross-sectional variation of the channel can be different, in particular adjacent channels being able to modulate differently.
• the channels on the base body at least partially run parallel to one another.
• the channels can be at least partially straight on the base body he stretches.
• the channels can have deflections at least in some areas, for example in connection with the use of the areas with a cross-sectional reduction and cross-sectional expansion. So can after a diversion in an inner radius of the canal, a narrowing of the canal may be useful.
• An angle of deflection can be between 0 ° and 180 °, for example.
• the channels can be designed to extend in an arc at least in some areas.
• the channels on the base body run along meanders at least in certain areas, in particular rectangular meanders.
• finite radii of curvature can be provided for flow deflection elements within the channels in the sense of an improved flow guidance.
• the base body can advantageously have a first side and a second side facing away from the first side.
• the channels can be arranged on the first side. Further channels can be arranged or formed on the base body on the second side.
• the further channels are advantageously arranged in the region of the elevations on the first side, and on the second side elevations are advantageously arranged between the further channels in the region of the depressions on the first side.
• a depression on the first side for forming a channel can accordingly have a corresponding elevation on the second side.
• an elevation on the first side between channels on the second side can have a corresponding depression and accordingly a channel.
• a channel structure, which can be a “negative” of the channel structure on the first side can be formed on the second side.
• overflow areas are preferably formed between the further channels that are adjacent to one another.
• the overflow areas are preferably designed to extend less high in the vertical direction than hump areas on the second side, which are arranged on the second side in the area of the valley areas.
• overflow areas can correspond to the saddle areas on the second side. These can be extended less high with respect to the hump areas, the hump areas being arranged at those areas where valley areas are formed on the first side. To a certain extent, the overflow areas can be viewed as "yokes" between the bucket areas.
• the base body forms, in particular, contact elements for contacting the flow element.
• contact elements for contacting the flow element.
• the contact elements are preferably designed in a planar manner.
• Planar abutment elements on the first and / or the second side allow an improved introduction of force to the flow element, in particular when it is used in a bipolar plate and an electrochemical device that includes or forms a fuel cell stack, for example.
• the contact elements on the second side advantageously form a common contact plane.
• the contact elements are arranged in an imaginary curved surface.
• the area has a relatively large radius that coincides with a radius of a gas diffusion layer.
• the flow element is advantageously formed in one piece.
• the flow element can be designed as a deformed part.
• the base body is formed in a stamping process by reshaping a sheet, in particular a metallic sheet.
• the flow element can accordingly be designed as a sheet metal part.
• the flow element can be made of metal, for example.
• metal is understood to be a metallic material that can be elemental or an alloy.
• metals are steels, in particular stainless steels, with the designations 1.4301, 1.4306, 1.4404 or 1.4438. Titanium or aluminum, for example, can be used as metal.
• the flow element When manufactured as a formed part, the flow element can be given a particularly robust design.
• an area of the base body with pronounced deformation can lie in an area with a normal level difference directly next to an area with less deformation, in particular an area with a reduced level difference. Since material "flows" from the immediate vicinity during forming and is accordingly put under tension, the less pronounced structure in its vicinity allows more extreme forming.
• this can in particular be understood to mean that the use of the saddle areas allows more extreme deformations in the area of the valley areas and the associated steep flanks of the elevations.
• the area with the normal level difference, ie the valley area is at the same time a normal width area. This allows larger radii on the flanks of the elevations, creating a Deformation in these areas of the base body with greater elongation is made easier.
• Planar contact elements on the second side are advantageously arranged on the abovementioned hump areas, with valley areas preferably being located opposite on the first side.
• valley areas preferably being located opposite on the first side.
• connection can be made, for example, by welding.
• the flow element is manufactured by means of a thermal molding process.
• the flow element is made of graphite.
• graphite is "baked into shape" by means of a thermal molding process.
• the flow element can for example be made from an embossed C-compound.
• Manufacturing the flow element from a composite material, in particular a carbon composite material can be advantageous.
• the flow element can be formed, for example, by means of an additive method.
• a coating and / or surface treatment of the base body and / or the flow element can be advantageous, for example for use in electrochemical cells.
• the channel structure of the flow element in particular forms a so-called flow field.
• Different types of flow field can be provided. These include, for example, a straight flow field, a meander flow field, a foot flow field and combinations and / or derivatives thereof.
• the present invention also relates to a use.
• a use according to the invention is a use of a flow element of the type mentioned above in a bipolar plate of an electrochemical device.
• a bipolar plate according to the invention is particularly suitable for an electrochemical device and according to the invention comprises at least one flow element of the type mentioned above.
• the bipolar plate advantageously comprises a first flow element and a second flow element, at least one flow element being a flow element of the type mentioned above.
• the first flow element and the second flow element are advantageously in contact with one another via corresponding contact elements.
• the contact elements are preferably designed to be planar. This also proves to be advantageous, for example, for a welded connection between the flow elements.
• the corresponding contact elements are preferably designed flat.
• contact elements are arranged on the first flow element. This can be understood to mean, for example, the abovementioned hump areas of the second side of the first flow element.
• the second contact element preferably comprises a channel structure on at least the side facing the first flow element.
• channels of the channel structure can be aligned with channels that are formed on the side of the first flow element facing the second flow element.
• the first flow element can be arranged on the second flow element, for example, in such a way that the depressions extend in the direction of the second flow element.
• the first flow element is arranged on the second flow element in such a way that the elevations extend in the direction of the second flow element.
• overflow paths are preferably formed between channels of the first flow element, preferably on a side of the base body that faces away from the saddle areas.
• This can in particular be the aforementioned second side, overflow paths being arranged on the overflow areas between the hump areas, which can preferably form contact elements for the second flow element.
• the second flow element is a flow element of the type mentioned above.
• the depressions of the first flow element can engage in the depressions of the second flow element in this case.
• the channels of the first flow element and of the second flow element are configured identically or essentially identically.
• the present invention also relates to a method.
• the invention is based on the object of providing a method with which a flow element can be produced which has a robust design and advantageous flow properties.
• a method for producing a flow element of the type mentioned above comprising the formation of a channel structure on a base body which extends in two main directions of extension oriented at an angle to one another and in a height direction oriented transversely and in particular perpendicular thereto has, with a plurality of channels which are arranged laterally next to one another, the channels formed by depressions in the base body and formed separately from one another by elevations of the base body arranged between the depressions, with areas with a normal level difference defined in the height direction as a height difference between one Elevation and an adjacent depression are formed as well as areas with a level difference reduced in relation to the normal level difference as a height difference between an elevation and an adjacent depression, i n Direction of the course of the ducts, at least in sections, repeating areas with normal level difference and areas with reduced level difference are formed and areas with reduced level difference of adjacent ducts based on their respective running direction are shifted against each other, the areas with reduced level difference formed by means of saddle areas
• the flow element is expediently formed by means of a forming process, and the process comprises the provision of a plate-shaped base body, the channel structure being formed by means of the forming process.
• the flow element is formed by means of a thermal molding process, the base body being formed integrally with the channel structure.
• the flow element is formed by means of an additive method, the base body being formed integrally with the channel structure.
• FIG. 1 a schematic perspective illustration of a bipolar plate according to the invention in a preferred embodiment, which comprises a preferred embodiment of a flow element according to the invention (first flow element) and a further flow element (second flow element);
• FIG. 2 a plan view of a first side of the first flow element in FIG. 1;
• FIG. 3 a perspective partial representation of the first flow element, sectioned along the line 3-3 in FIG. 2;
• FIG. 4 an enlarged detailed illustration of the first flow element in a perspective view
• FIG. 5 a partial sectional view of the first flow element, the section running along the line 5-5 in FIG. 2;
• Figure 6 a sectional view of the first flow element along the
• FIG. 7 a perspective illustration of the second flow element from FIG. 1;
• FIG. 8 a perspective illustration of the first flow element from FIG. 1 from a second side facing away from the first side;
• FIG. 9 an enlarged illustration of detail A in FIG. 8;
• FIG. 10 a plan view of the first flow element from the second side
• FIG. 11 a sectional view along the line 11-11 in FIG. 10
• FIG. 12 a sectional view along the line 12-12 in FIG. 10
• FIG. 13 a sectional view along the line 13-13 in FIG. 10
• FIG. 14 again a plan view of the first flow element from the second side;
• FIG. 15 a sectional view along the line 15-15 in FIG. 14
• FIG. 16 a sectional view along the line 16-16 in FIG. 14
• FIG. 17 a sectional view along the line 17-17 in FIG. 14
• FIG. 18 a plan view of a section of a further flow element according to the invention from a first side;
• FIG. 19 a sectional view of a further bipolar plate according to the invention in a schematic representation.
• FIG. 20 a sectional view of a further bipolar plate according to the invention in a schematic representation.
• FIG 1 shows a schematic perspective representation of an overall with the reference numeral 10 assigned advantageous embodiment of a fiction, contemporary bipolar plate for use in an electrochemical device not shown in the drawing, for example a fuel cell device.
• the bipolar plate 10 can for example be arranged in a fuel cell stack.
• Gas diffusion layers (GDL, gas diffusion layer) can be positioned on both sides of the bipolar plate 10.
• Figure 1 shows this with dashed lines schematically with reference numeral 12 on an underside of the bipolar plate 10 shown in the drawing.
• the bipolar plate 10 comprises a first flow element 14, which is a preferred embodiment of a flow element according to the invention, and a second flow element 16.
• the flow element 14 has a first side 18 which faces the gas diffusion layer 12, and a second side 20 which faces away from it and which faces the second flow element 16. As will be explained below, the flow element 14 rests on the second side 20 on the second flow element 16.
• the flow element 14 comprises a plate-shaped base body 22 which extends along two main directions of extension 24, 26 is, which can in particular be perpendicular to each other.
• a height direction 28 is aligned transversely and in particular perpendicular to the main extension directions 24, 26.
• the flow element 14 extends in the height direction 28, the height of the flow element 14 being H in the height direction 28.
• the base body 22 and the flow element 14 as a whole can be formed, for example, as a formed part, in particular from a metal sheet, as has already been explained above. Alternatively, for example, manufacturing using a thermal molding process or generative manufacturing is possible. Reference is made to the above statements.
• the base body 22 comprises a channel structure 30 with a plurality of channels 32.
• the channels 32 are designed in a straight line and run parallel to one another.
• non-straight channels such as curved channels, channels with deflections or channels that run along meanders are also conceivable.
• the channels 32 each have a running direction 34. A fluid flowing in the channels 32 can flow with one flow direction, wherein the orientation of the flow can be aligned along both orientations of the course direction 34.
• the fluid can in particular be a reactant, for example hydrogen gas or air for supplying the gas diffusion layer 12.
• a reactant for example hydrogen gas or air for supplying the gas diffusion layer 12.
• the channels 32 comprise free cross-sectional areas through which the fluid can flow, which can be changed over their respective direction 34.
• This offers the advantage of a better supply of the gas diffusion layer 12 with the reactants.
• the cross-sections of the channels 32 modulate both along the vertical direction 28 and along a transverse direction 36 which is oriented transversely and, in particular, perpendicular to the direction 34.
• the static and dynamic pressure of the fluid in the channels 32 are modulated.
• a pressure drop across the channels 32 is kept ge as low as possible by the advantageous embodiment of the Strö flow element explained below.
• the modulation of the static and dynamic pressure leads to an improved supply of the gas diffusion layer 12 with the fluid.
• the channels 32 are formed by depressions 38 and intervening elevations 40 of the base body 22.
• the fluid can flow in the recess 38.
• Adjacent channels 32 each have depressions 38 that are separated from one another by an elevation 40.
• the depth of the respective channels 32 varies along the course direction 34. Areas with a normal level difference N n are provided. These areas, which are identified in the drawing with the reference numeral 42, have a depth with a normal level difference Nn, which is defined from the height difference along the height direction 28 between a depression 38 and an adjacent elevation 40.
• the channels 32 have areas marked with the reference numeral 44 with a reduced level difference N r .
• the reduced level difference N r is smaller in the height direction 28 than the normal level difference Nn.
• the reduced level difference N r is also given in the height direction 28 by a height difference between a depression 38 and an adjacent elevation 40.
• the channels 32 in areas 42 with normal difference Nn are deeper than channels 32 in areas 44 with reduced level difference N r .
• the regions 42 are formed by means of the present convex saddle regions 46, and the regions 44 are formed by means of the present concave valley regions 48.
• the saddle areas 46 and the valley areas 48 alternate with one another. Two valley areas 48 are adjacent to a respective saddle area 46 and vice versa.
• the channels 32 in this way have an overall periodic modulation of the channel depth by means of saddle areas 46 and valley areas 48.
• the periods or "phases" of the modulation are each shifted by half a period between adjacent channels.
• a saddle area 46 of a channel 32 is a valley area 48 of a neighboring channel 32 opposite and vice versa.
• “opposite” refers in particular to the transition from one channel 32 via the adjacent elevation 40 to the adjacent channel 32 (FIGS. 3 and 4).
• the saddle area 46 and the valley area 48 each have a substantially planar section 50 and 52, respectively.
• the sections 50, 52 are aligned parallel to one another and in particular parallel to a contact plane 54 of the flow element 14 on the first side 18, which will be discussed below.
• the normal level difference N n at section 52 and the reduced level difference Nr at section 50 are determined, but this is not restrictive for the invention.
• the section 52 forms a valley floor of the valley area 48, the section 50 an apex of the saddle area 46.
• a clerk The angle of the bevels 56 with respect to the respective plane defined by the section 50 or 52 is, for example, approximately 2 ° to 60 °, preferably approximately 2 ° to 40 °.
• the saddle areas 46 and the valley areas 48 adjoin one another at the slopes 56;
• the respective saddle area 46 extends in the present example from the center of a rising slope 56 over the section 50 to a falling slope 56.
• the respective valley region 48 extends from the center of a sloping slope 56 over the section 52 to a rising slope 56.
• a respective length Ls of a saddle area can be, for example, approximately 1 mm to 25 mm, preferably approximately 2 mm to 10 mm.
• a respective length LT can correspond to the length Ls of the saddle area or be different from this.
• Saddle areas 46 and valley areas 48 can accordingly be the same size or essentially the same size in the course direction 34.
• a period (period length P) within a respective channel 32 is, for example, approximately 2 mm to 50 mm, preferably approximately 4 mm to 20 mm.
• a respective curvature of the base body 22 at the saddle area 46 and at the valley area 48 in the direction 34 is less than a curvature of the base body 22 in each case along the transverse direction 36.
• Flanks 58 of the elevations 40 run less steep at the saddle areas 46 than at the valley areas 48.
• the saddle area 46 which is flatter in relation to the valley area 48, allows greater design leeway with regard to the steepness of the flanks and / or radii of the base body 22.
• the channels 32 are also modulated with regard to their width in order to achieve different cross-sections that can be freely flowed through.
• the base body 22 forms normal width regions 60 and narrowing regions 62 on the channels 32.
• a width BN of a respective channel 32 is greater than a width Bvan narrowing regions 62.
• the normal width areas 60 and the narrowing areas 62 are arranged in the flow element 14 periodically repeating along the direction 34 direction.
• an extension along the course direction 34 of the normal width regions 60 is an extension of the narrowing regions 62.
• the narrowing areas 62 are arranged in the present case at saddle areas 46 and normal width areas 60 at valley areas 48. This means that at points in which the channels 32 are less deep, they also have a smaller width. Conversely, channels at the deeper valley areas 48 are wider. In this way, an effective cross-sectional modulation both in the depth and in the width of the channels to achieve an effective modulation of the static and dynamic pressure of the fluid can be achieved.
• the formation of the convex saddle areas 46 and the correspondingly concave valley areas 48 and the configuration of the normal width areas 60 and narrowing areas 62 explained below keep a pressure loss across the direction 34 of the channels 32 as low as possible.
• Lengths LN of the normal width area 60 and Lv of the narrowing area 62 can be identical and match the lengths Ls and LT of the saddle area 46 and the valley area 48, or different from one another and different from the latter. Accordingly, for example, the period length P for the normal width areas 60 and the narrowing areas 62 match the period length P for the saddle areas 46 and valley areas 48.
• a narrowing area 62 of a channel 32 is opposite a normal width area 60 of an adjacent channel 32, and vice versa.
• the normal width areas 60 and the narrowing areas 62 in adjacent channels 32 are advantageously shifted by half a period length P from one another.
• the base body 22 thus advantageously has, on the one hand, saddle areas 46 and valley areas 48 and, on the other hand, normal width areas 60 and narrowing areas 62 in a regular arrangement on the first side 18.
• Saddle areas 46, valley areas 48, normal width areas 60 and narrowing areas 62 of adjacent channels 32 are arranged along the direction 34 "on a gap".
• the respective widths of the channels 32 at the normal width regions 60 and the narrowing regions 62 are not constant.
• the width BN can be determined at the normal width regions 60 in the course direction 34 essentially in the center of the section 52.
• the width Bv of the narrowing region 62 can, for example, be determined in the direction 34 essentially in the middle of the section 50.
• the normal width area 60 is formed in such a way that the flanks 58, which delimit the channel 32, initially run away from one another along the course direction 34 and then run towards one another again. Conversely, the flanks 58 of the elevations 40 delimiting the channel 32 at egg nem narrowing region 62 initially towards one another and then away from one another.
• the narrowing area 62 thereby forms a constriction, the narrowest point of which is preferably formed in the direction 34 in the middle of the Sat tel Kunststoffes 46
• the normal width area 60 forms a widening, the widest point in the direction 34 in the middle of the valley area 48 is formed ( Figure 4).
• a width of a respective channel 32 can for example be measured in relation to the height direction 28 independently of the depth of the respective channel 32 at the same point, as is symbolized in FIG. Alternatively, for example, a width of a respective channel 32 can be measured at half the height of the flank 58 between the depression 38 and the elevation 40.
• Reduced level difference NR from 0.05 mm to 0.6 mm, preferably from 0.1 mm to 0.5 mm.
• Width BNam normal width range 60 from 0.3 mm to 3 mm, preferably 0.4 mm to 2 mm.
• Width Bv at the narrowing area 62 from 0.2 mm to 2 mm, preferably 0.3 mm to 1 mm.
• the material thickness before the deformation of the base body 22 can, for example, in particular depending on the application of the flow element, for example in a fuel cell device, be approximately 40 ⁇ m to approximately 500 ⁇ m, preferably approximately 50 ⁇ m to 120 ⁇ m.
• a rather large material thickness is used, with a PEM fuel cell a rather low material thickness.
• the material thickness of the base body 22 in the present case is not included in the depth and not in the width of the channels.
• the respective channels 32 are designed symmetrically with respect to a channel center plane M in the present case.
• the saddle areas 46, valley areas 48, normal width areas 60 and narrowing areas 62 are each designed symmetrically with respect to the channel center plane M and a channel transverse plane Q at the respective area 46, 48, 60 and 62.
• the elevations 40 can have an essentially constant width over the course direction 34 in the transverse direction 36.
• the elevations 40 each form a contact element 64.
• the contact element 64 is designed in a planar manner in the present case.
• the contact elements 64 of the elevations 40 in particular form a common plane, the contact plane 54 already mentioned.
• the gas diffusion layer 12 can rest against the flow element 14 on the first side 18 and consequently assume a defined position relative to this.
• the contact elements 64 have a zigzag shape in the direction 34. In the present case, this is preferably due to the configuration of the normal width areas 60 and the narrowing areas 62 as areas with widening or areas with constriction. Due to the zigzag shape of the contact elements 64, the flow element 14 on the first side 18 has a high assembly tolerance when bipolar plates 10 and gas diffusion layers in between are stacked within a fuel cell stack.
• the flow element 14 is arranged on the flow element 16 in such a way that the depressions 38 face the flow element 16 and the elevations 40 face away from the flow element 16. Accordingly, the second side 20 is the side of the flow element 14 facing the flow element 16.
• the flow element 14 is designed as a “negative” of the first side 18, so to speak.
• elevations 66 are arranged on the second side 20 on the base body 22, and at the location of the elevations 40, depressions 68 are arranged on the second side.
• the base body 22 also forms a channel structure 70 with channels 72 on the second side 20.
• the channels 72 on the second side 20 serve, for example, to guide a coolant fluid.
• overflow areas 74 are formed at the location of the saddle areas 46.
• hump areas 76 are formed on the second side 20 in the area of the valley areas 48.
• the overflow areas 74 are less high in the height direction 28 than the hump areas 76. In this way, there is the possibility that between adjacent channels 72 on the second side 20 Overflow path of the fluid across the overflow areas 74 into adjacent channels 72 (arrows 78 in Figure 9). In this way, an effective fluid flow can also be achieved on the second side 20 through the flow element 14, in particular with regard to temperature control (cooling and / or heating) by means of a cooling medium.
• the hump areas 76 form contact elements 80 on the second side 20.
• the flow element 14 rests against the flow element 16 via the contact elements 80.
• the contact elements 80 are arranged in the area of the sections 52, on the second side 20.
• the contact elements 80 are designed to be planar.
• the contact elements 80 define a contact plane 82.
• the second flow element 16 likewise has a base body 84 which extends in the main directions of extension 24 and 26 and which extends in the height direction 28.
• the flow element 16 has a first side 86 facing away from the flow element 14 and a second side 88 facing the flow element 14.
• the base body 84 forms a channel structure 90 with channels 92 which are formed by depressions 94 and elevations 96 lying therebetween (FIGS. 1 and 7).
• the flow elements 14, 16 are oriented relative to one another in such a way that the channels 72 are aligned with the channels 92 and the elevations 96 can lie flat against the contact elements 80.
• the flow element 16 comprises base-like support elements 98 which are enlarged in both main directions of extension 24, 26 in relation to the elevations 96.
• a connection of the flow elements 14, 16 is preferably provided on the support elements 98, for example by welding.
• the support elements 98 are preferably designed in a planar manner and can rest flat against the contact elements 80 of the flow element 14. Since with the support points 98 on the hump areas 76, ie on the two th side 20, the relatively wide valley areas 48 opposite. As a result, reliable support can take place, in particular in the stack direction.
• the base body 84 On the first side 86, the base body 84 also forms a channel structure 100, which is used, for example, to transport a further reactant.
• FIG. 18 shows a detail of a flow element according to the invention, assigned the reference numeral 110, in a plan view of the first side 18.
• the channels 32 are shown with depressions 38 and elevations 40.
• saddle areas 46 and valley areas 48 are hidden in FIG. Flanks and radii of the channels 32 are also not shown for the same reason.
• areas 112 with a widened cross-section are provided and areas 114 with a reduced cross-section.
• the first-mentioned areas can also be referred to as diffuser 116, the second-mentioned areas as confuser 118.
• the cross-section expands, in the area of a confuser 118 the cross-section decreases.
• the direction of flow is indicated by arrow 120.
• the diffuser 116 and the confuser 118 have different extensions along the direction 34.
• the diffuser 116 extends in particular longer than the confuser 118.
• the diffuser 116 has an opening angle 122, the confuser 118 a reduction angle 124. Legs of the angles 122 and 124 each run along the flanks 58.
• the opening angle 122 and the reduction angle 124 are different from one another. It can be advantageous here if the reduction angle 124 is greater than the opening angle 122.
• the opening angle is approximately 0.5 ° to 20 °, preferably approximately 1 ° to 5 °.
• the reduction angle is, for example, approximately 0.5 ° to 20 °, preferably approximately 1 ° to 10 °.
• a respective channel 32 comprises successive deflections 126 and is not designed in a straight line.
• To the steering angle is in the present example about 10 ° to 50 °.
• the elevations 40 in the course direction 34, have different widths.
• the adaptation of the widths of the elevations 40 to the changes in cross section of the channels 32 and the deflections 126 can serve in particular to avoid dead areas of the flowing fluid.
• a larger contact surface, in particular for the gas diffusion layer 12, can be provided.
• the flow element 110 can be part of a bipolar plate according to the invention.
• a modification of the embodiment shown in FIG. 18 can be provided in which a diffuser 116 and a confuser 118 are present without the deflections 126 shown in FIG common center line, which can be aligned in the channel direction 34.
• FIG. 19 shows, in a sectional view, an advantageous embodiment of a bipolar plate according to the invention, assigned the reference numeral 130.
• the bipolar plate 130 comprises the flow element 14 and a further flow element 132, which the flow element 14 faces via its second side 20.
• the flow element 132 has a first side 86 facing away from the flow element 14 and a second side 88 facing the flow element 14.
• the channel structure 90 with channels 92 is formed on the base body 84.
• the elevations 96 engage in the depressions 68.
• the elevations 66 engage in the depressions 94. In this way, a very compact bipolar plate 130 can be formed, whereby a preferred robust mutual support can be achieved at the same time.
• the bipolar plate 130 it can be provided that no fluid flows in channels 72. Instead, fluid flows between the flow elements 14 and 132 in the channels 92.
• the depressions 94 are designed to be deeper than the depressions 38 (FIG. 19).
• a lateral distribution of the fluid can be achieved, for example, by differences in the slopes or flanks of the respective depressions and elevations.
• FIG. 18 shows, in a manner corresponding to FIG. element 142 includes.
• the flow element 142 is identical or at least functionally identical to the flow element 14.
• a second side 20 of the flow element 142 faces the second side 20.
• the flow elements 14 and 142 preferably lie flat against one another.
• the flow elements 14, 142 are positioned shifted relative to one another in the transverse direction 36. In this way, the contact elements 80 of a respective flow element 14, 142 can contact the respective second side 20 of the other flow element 142 or 14, specifically in the area of the respective elevations 40. Corresponding contact areas are identified in FIG.
• bipolar plate 12
• gas diffusion layer 14
• first flow element 16
• second flow element 18
• first side 20
• second side 22
• base body 24
• main direction of extent 26
• height direction 30
• channel structure 32
• transverse direction 38
• Basic body first side, second side

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• 2020
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