Patent Application
20230327144
The present application claim priority to German Patent Application No. 20 2022 101 861.8, entitled “SEPARATOR PLATE AND METHOD FOR PRODUCING SAME”, filed Apr. 7, 2022. The entire contents of the above-listed application is hereby incorporated by reference for all purposes.
The present disclosure relates to a separator plate for an electrochemical system, and to a method for producing same. The electrochemical system may be, for example, a fuel cell system, an electrochemical compressor, or an electrolyzer.
Known electrochemical systems usually comprise a plurality of separator plates, which are arranged in a stack so that each two adjacent separator plates enclose an electrochemical cell. An electrochemical cell usually comprises a membrane, which is provided with electrodes and with a catalyst layer, and optionally gas diffusion layers facing towards the separator plates. For instance, the actual membrane is not formed over the entire surface of a separator plate, but instead extends substantially in the area that forms the electrochemically active region of the system. This is usually arranged substantially centrally and is surrounded by a frame. This frame is usually formed by an electrical insulator, for example a polymer-based film. The frame also has the task of electrically insulating adjacent separator plates from each other and thus avoiding a short-circuit. Besides the membrane, the electrodes and the catalyst layer(s), the membrane electrode assembly, hereinafter also abbreviated as MEA, also comprises the frame, which is sometimes also referred to as a reinforcing frame, but not the gas diffusion layer(s).
The separator plates usually each comprise two individual plates, which are connected to each other along their rear sides facing away from the electrochemical cells. The separator plates may serve, for example, for electrically contacting the electrodes of the individual electrochemical cells (for example fuel cells) and/or for electrically connecting adjacent cells (series connection of the cells). The separator plates may also be used to dissipate heat that is generated in the cells between the separator plates. Such waste heat may be generated, for example, during the conversion of electrical or chemical energy in a fuel cell. In the case of fuel cells, bipolar plates are often used as separator plates.
The separator plates or the individual plates of the separator plates usually each have at least one through-opening. In the separator plate stack of the electrochemical system, the through-openings of the stacked separator plates, which through-openings are arranged in an aligned or at least partially overlapping manner, then form media channels for supplying or discharging media. The through-openings are accordingly also formed in the frame of the membrane electrode assembly. For example, the through-openings in the frame are formed with a smaller diameter than in the separator plates so that the resulting overhang of the frame insulates the adjacent separator plates from each other. In order to seal off the through-openings or the media channels formed by the through-openings of the separator plates, known separator plates also have bead arrangements, which are arranged in each case around the through-opening of the separator plate.
The individual plates of the separator plate may additionally have channel structures for supplying one or more media to an active region of the separator plate and/or for conveying media away therefrom. The active region of the separator plate is usually defined in such a way that it may for example enclose or bound the active region of an electrochemical cell. By way of example, the media may be fuels (for example hydrogen or methanol), reaction gases (for example air or oxygen) or a coolant as supplied media, and reaction products and heated coolant as discharged media. In the case of fuel cells, the reaction media, e.g. fuel and reaction gases, are usually guided on the surfaces of the individual plates that face away from each other, while the coolant is guided between the individual plates.
The flanks of the bead arrangement arranged around the through-opening of the separator plate may have one or more apertures, as shown for example in DE 102 48 531 A1. These apertures serve to establish a fluid connection between the through-opening of the separator plate and the active region of the separator plate. After the individual plate has been embossed, the apertures are usually created by punching or cutting the plate material. However, since the apertures are located in the flanks of the bead arrangement, a relatively complicated 3D cut is required. In addition, the apertures may form sharp edges, which may damage the MEA, for example the film of the reinforcing frame, or may even perforate it or cause relatively large cracks therein. The apertures formed in the bead flank also cause a local weakening of the bead flank, as a result of which the stiffness of the latter is reduced in some regions.
It is also known from document DE 102 48 531 A1 that the separator plate may have one or more conveying channels instead of the apertures formed in the bead flank, which conveying channels adjoin the bead flank on an outer side of the bead arrangement and are in fluid connection with a bead interior of the bead arrangement. Such conveying channels which adjoin the bead flank may be combined with, for example, bead-like channel sections, as shown in WO 2020/174038 A1. The supply of a medium from the through-opening, through the bead arrangement, to the electrochemically active region of the separator plate can take place in an even more targeted manner with the aid of such conveying channels. Such conveying channels may also improve the discharging of the medium from the electrochemically active region, through the bead arrangement, to the through-opening. Overall, therefore, the efficiency of the electrochemical system can be increased.
The aforementioned conveying and distribution channels are therefore part of a fluid connection of the through-opening to the electrochemically active region and as such are provided only in a section of the bead arrangement that usually extends between the through-opening and the electrochemically active region. However, this asymmetrical design of the bead arrangement may lead to inhomogeneous bead compression in the stack, which in turn may lead to leaks in the stack or system.
The object of the present disclosure is to provide a separator plate for an electrochemical system that at least partially solves the problems mentioned above. The object of the present disclosure is also to provide a method for producing such a separator plate.
This object is achieved by a separator plate for an electrochemical system according to the independent claims, and by a method for producing such a separator plate according to the further independent claim. Specific embodiments are described in the dependent claims and in the description below.
Accordingly, a separator plate for an electrochemical system is proposed, comprising a first individual plate and a second individual plate, which are connected to each other. In a first variant, the separator plate comprises the following:
The conveying channel formed in the second individual plate leads opens a region of the first individual plate containing the first aperture. “Region of the first individual plate containing the first aperture” may refer either to opening directly into the first aperture or to opening indirectly into the first aperture, with the flow still passing through a fluid space spanned by the first individual plate. In addition, the conveying channel formed in the second individual plate fluidically connects the bead interior of the bead arrangement to the first aperture formed in the first individual plate.
Since the first aperture extends substantially parallel to the plate plane, the first aperture can be punched or cut parallel to the plate plane. There is thus no need for complicated 3D cuts when creating the first aperture. This also reduces the risk of damage being caused to the MEA, for example its reinforcing frame, by angled, sharp edges of the first aperture.
The first aperture is therefore not formed in a bead flank of the bead arrangement that extends at an angle to the plate plane. The first aperture is usually also spaced apart from the bead arrangement. The first aperture may be located, for example, on a side of the bead arrangement facing towards the through-opening or on a side of the bead arrangement facing towards the active region. The conveying channel may accordingly be arranged on a side of the bead arrangement facing away from the through-opening or on a side of the bead arrangement facing towards the through-opening.
The conveying channel may be formed by the plate material of the second individual plate. The present disclosure therefore also encompasses a method for producing a separator plate. In said method, the bead arrangement and/or the at least one conveying channel is integrally formed in the individual plate(s), such as the conveying channel of the second individual plate is integrally formed in the second individual plate, by hydroforming, deep-drawing and/or embossing, such as vertical and/or roller embossing. In the description below, the term “embossing” or “embossed” can be understood to refer to hydroforming, roller embossing, vertical embossing and/or deep-drawing. This method step is usually carried out simultaneously with the integral formation of the other flow-guiding structures, such as the fluid-guiding channels of the electrochemically active region. For example, in the case of large separator plates, roller embossing may require lower pressing forces per formed unit area than the other methods mentioned.
Furthermore, the at least one first aperture may be created in the first individual plate, in particular may be punched out of the latter, before or after the bead arrangement has been integrally formed. A vertical and/or rolling punching process can be used for this. It is possible for these simple methods to be used, for example after the aforementioned structures have been integrally formed, since the first aperture extends substantially parallel to the plate plane. Cutting or punching in surfaces which are sloping—e.g. at an angle to the plate plane—is more difficult to implement with regard to the process and the tools and may cause sharp edges.
In the context of this specification, a fluid connection or a fluidic connection may be a direct connection without intermediate elements or an indirect connection by way of additional intermediate elements.
The fluidic connection of the bead interior to the first aperture formed in the first individual plate by means of the conveying channel formed in the second individual plate may be established without intermediate channels or conveying sections—e.g. by means of a direct fluidic connection—or alternatively via further channels or conveying sections—e.g. via an indirect fluidic connection. These further channels or conveying sections for establishing the fluidic connection between the conveying channel formed in the second individual plate and the bead interior may be present, for example, in the first individual plate and/or in the second individual plate.
The expressions “substantially parallel” and “substantially orthogonal” with regard to two components are intended to include manufacturing tolerances and in the context of the present specification are intended to mean that slight deviations from parallelism or orthogonality are permitted, so that a corresponding angle between the respective components may deviate by between at most −30° and/or +30°, −20° and/or +20°, −10° and/or +10°, or even −5° and/or +5°. This is also intended to apply to the size of the aperture.
It may be provided that an orthogonal projection of the first aperture perpendicular to the plate plane onto the second individual plate defines a projection area, wherein the second individual plate has at least part of the conveying channel in the region of the projection area.
Often, at least in some regions, the conveying channel extends from the bead arrangement in the direction of the electrochemically active region. It may be provided that, at least in some regions, the conveying channel extends substantially parallel, at an angle and/or perpendicular to a main direction of extension of the bead arrangement. The conveying channel may therefore comprise various sections, which are fluidically connected to each other and extend in different directions. The conveying channel may adjoin the bead arrangement, such as a bead flank of the bead arrangement.
The main direction of extension of the bead arrangement is usually substantially parallel to an edge that bounds the through-opening. If the bead arrangement comprises a wavy course with convex and concave sections, the convex and concave sections of the wavy course in each case merge into each other at a turning point. The aforementioned main direction of extension is then superimposed on the wavy shape of the bead arrangement. The main direction of extension then results from the line connecting the turning points of the neutral axis of the bead arrangement, such as of the bead top of the bead arrangement.
Optionally, at least one conveying channel is provided in the first individual plate, which conveying channel may be designed as a fluidic connection piece between the bead interior and the conveying channel in the second individual plate. For example, the first individual plate may have a conveying channel which is fluidically connected to the bead interior, in some regions overlaps with the conveying channel of the second individual plate and is spaced apart from the first aperture.
However, it is also possible that no conveying channel is formed in the first individual plate, or else just one conveying channel which is only fluidically connected to the bead interior via the conveying channel in the second individual plate. It may therefore be provided that, in the first individual plate, no conveying channel extends between the bead arrangement and the first aperture.
The expression “between two elements” may on the one hand refer only to the points on the shortest straight connecting line between the two elements. As an alternative or in addition, it may also refer to points located on further, non-shortest straight lines connecting the elements, which enclose at most an angle of 45° with the shortest straight connecting line.
The at least one conveying channel may have a bead-like structure with a top and a respective flank on each side thereof, which flanks, at a bead foot, pass tangentially into a plane extending parallel to the plate plane. The top may be curved or flat in cross-section. In the direction of extension of the conveying channel, the top may be planar or arranged at an angle.
If conveying channels are formed both in the second individual plate and in the first individual plate, said conveying channels may extend in a fully or partially overlapping manner in orthogonal projection onto the plate plane or may also be completely offset from each other. For example, sections of the conveying channels that directly adjoin the flank of the bead arrangement, e.g. sections extend substantially perpendicular to the bead arrangement, may extend in a fully or partially overlapping manner or may be completely offset from each other.
In one embodiment, the first aperture is formed in a region of the plate that lies in a plate plane of the first individual plate. Alternatively, the first aperture may be formed in an embossed region of the plate. For example, the first aperture may be surrounded by an embossed structure, which protrudes out of the plate plane for example in the same direction as the bead arrangement. A height of the embossed region or of the embossed structure, measured perpendicular to the plate plane, may be smaller than a height of the bead arrangement, for example in the non-compressed state of the plate stack and/or the bead arrangement. The embossed region may form a plateau, in which the first aperture is formed; however, the embossed region may also form a bead which is closed on itself in the manner of a ring, wherein the first aperture is formed in the region surrounded by the bead and thus lies in a different plane than the projecting regions of the bead. By way of example, the bead may extend in a plane that extends between the plane of the bead top and the plate plane of the first individual plate, while the aperture extends in the plate plane of the first individual plate or in a plane between the plate plane of the first individual plate and the plane of the projecting region of the bead. The embossed region or the embossed structure containing the aperture may have, for example, an oval, rounded-rectangular or elliptical basic shape or may extend in the manner of a channel, for example at least partially along the conveying channel formed in the second individual plate.
It is also possible that a plurality of first apertures are formed in the first individual plate. In this case, it may be that these apertures are arranged on the side of the bead arrangement facing away from the through-opening and/or on the side of the bead arrangement facing towards the through-opening such that, in the first individual plate, an embossed structure is formed, at least in some sections, between at least two of the two first apertures. The embossed structure may be designed such that it extends away from the plate plane in the same direction as the bead arrangement. The embossed structure may have an oval, rounded-rectangular or elliptical basic shape and may be arranged centrally between the two first apertures. As an alternative or in addition, at least one conveying channel may also extend as an embossed structure, at least in some sections, between the two first apertures.
A contact area for the MEA reinforcing frame may be provided both by means of a bead-like embossed structure, which surrounds at least one aperture, and by a separate embossed structure, the contact area being spaced apart from the plane of the aperture so that a sufficient flow space is spanned for the medium flowing through the at least one first aperture or the at least two first apertures. There is no need for either the embossed structure or the bead-like embossed structure to extend in a plane parallel to the plate plane; they may also extend at an angle to the plate plane.
The first aperture may alternatively be surrounded, such as partially surrounded, for example, by an embossed structure which projects out of the plate plane in the opposite direction to the bead arrangement. Such a first aperture may therefore extend in a plane that also extends within the conveying channel of the second individual plate.
Optionally, the first individual plate may have a first sealing bead arranged around the through-opening for sealing off the through-opening. The second individual plate may accordingly have a second sealing bead arranged around the through-opening for sealing off the through-opening. The first sealing bead and the second sealing bead may be arranged in an overlapping manner and may form the aforementioned bead arrangement with a common sealing bead interior, which is fluidically connected to the through-opening of the separator plate. The first sealing bead and the second sealing bead are typically formed on opposite sides of the separator plate and usually point away from each other with their bead tops. The first sealing bead and the second sealing bead are usually designed as full beads and accordingly each usually comprise two bead flanks. The bead flanks of the respective sealing beads are often connected to each other by a straight or curved bead top. Alternatively, it is possible that the sealing bead interior is spanned by just one sealing bead in one of the first and second individual plates, e.g. only in the first or only in the second individual plate, and the complementary individual plate extends for example in a flat manner in the regions in question.
It may be provided that, at least in some regions, the conveying channel extends from the second sealing bead in the direction of the electrochemically active region or in the direction of the through-opening. The conveying channel may adjoin the second sealing bead, such as a bead flank of the second sealing bead.
The present disclosure permits a large number of combinations with regard to the number of conveying channels and first apertures. In a first variant, one first aperture in the first individual plate is connected to one conveying channel in the second individual plate, for instance a conveying channel extending substantially perpendicular to the bead arrangement. However, it is also possible that a plurality of first apertures in the first individual plate overlap with one conveying channel in the second individual plate, at least in some sections, so that one conveying channel is in fluid connection with a plurality of apertures. It is also possible to feed at least two first apertures from a single conveying channel in the second individual plate, which conveying channel extends perpendicular to the bead arrangement, or to discharge fluid from these first apertures via this conveying channel. It is also possible to overlap, in some sections, one first aperture in the first individual plate with a plurality of conveying channels in the second individual plate and thereby fluidically connect it thereto.
In a second variant of the present disclosure, the separator plate comprises the following:
In this variant, too, the conveying channel opens into a region of the first individual plate containing the first aperture, such as a region spanned by the first individual plate and containing the first aperture, and fluidically connects the bead interior of the bead arrangement to the first aperture formed in the first individual plate. Once again, it is not necessary for the aperture to be formed by means of a complicated 3D punching process; instead, it can be created by means of a simple 2D punching process.
In this second variant, the conveying channel may be integrally formed in the first individual plate. The conveying channel may be formed by the plate material of the first individual plate. In this second variant, a bead arrangement may extend around the through-opening in the second layer, but it is also possible that no corresponding bead arrangement is formed in the second layer.
Many of the above-mentioned embodiments of the first variant, including the method, can also be realized with the second variant of the present disclosure, provided that they do not conflict therewith.
In both variants, the first individual plate may have at least one first through-opening for the passage of a fluid, wherein the second individual plate has a second through-opening for the passage of the fluid. The first through-opening and the second through-opening are usually arranged in alignment or in an overlapping manner at least in some sections and form the aforementioned through-opening of the separator plate, around which the bead arrangement is arranged.
As indicated above, the through-opening may be designed for the passage of a reaction medium, such as a reaction gas, or a coolant, such as a cooling fluid. A through-opening may form an inlet opening or feed opening or an outlet opening or discharge opening for the fluid. In the present specification, a conveying sequence leading from the edge of a through-opening to a first aperture is also referred to as a bead passage since it serves to enable a fluid to pass through the region crossed by the bead arrangement.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
Exemplary embodiments of the separator plate and of the electrochemical system are shown in the figures and will be explained in greater detail on the basis of the following description.
Here and below, features that recur in different figures are denoted by the same or similar reference signs.
In alternative embodiments, the system 1 may also be designed as an electrolyzer, as an electrochemical compressor, or as a redox flow battery. Separator plates can likewise be used in these electrochemical systems. The structure of these separator plates may then correspond to the structure of the separator plates 2 explained in detail here, although the media guided on and/or through the separator plates in the case of an electrolyzer, an electrochemical compressor or a redox flow battery may differ in each case from the media used for a fuel cell system.
The z-axis 7, together with an x-axis 8 and a y-axis 9, spans a right-handed Cartesian coordinate system. The separator plates 2 each define a plate plane, each of the plate planes of the separator plates being oriented parallel to the x-y plane and thus perpendicular to the stacking direction or to the z-axis 7. The end plate 4 usually has a plurality of media ports 5, via which media can be supplied to the system 1 and via which media can be discharged from the system 1. Said media that can be supplied to the system 1 and discharged from the system 1 may comprise for example fuels such as molecular hydrogen or methanol, reaction gases such as air or oxygen, reaction products such as water vapor or depleted fuels, or coolants such as water and/or glycol.
Both known separator plates, as shown in
The individual plates 2a, 2b typically have through-openings, which are aligned with one another and form through-openings 11a-c of the separator plate 2. When a plurality of separator plates of the same type as the separator plate 2 are stacked, the through-openings 11a-c form fluid-guiding lines which extend through the stack 6 in the stacking direction 7 (see
In order to seal off the through-openings 11a-c with respect to the interior of the stack 6 and with respect to the surrounding environment, the first individual plates 2a may each have sealing arrangements in the form of sealing beads 12a-c, which are arranged in each case around the through-openings 11a-c and in each case completely surround the through-openings 11a-c. On the rear side of the separator plates 2, facing away from the viewer of
In an electrochemically active region 18, the first individual plates 2a have, on the front side thereof facing towards the viewer of
The sealing beads 12a-12c are crossed by passages 13a-13c, which are in each case integrally formed in all the individual plates 2a, 2b, and of which the passages 13a are formed both on the underside of the upper individual plate 2a and on the upper side of the lower individual plate 2b and form a connection between the through-opening 11a and the distribution region 20, while the passages 13b in the upper individual plate 2a and the passages 13c in the lower individual plate 2b establish a corresponding connection between the through-opening 11b or 11c and the respectively adjoining distribution region 20. By way of example, the passages 13a enable coolant to pass between the through-opening 12a and the distribution and/or collection region 20, so that the coolant enters the distribution and/or collection region 20 between the individual plates 2a, 2b and is guided out therefrom.
Furthermore, the passages 13b enable hydrogen to pass between the through-opening 12b and the distribution or collection region on the upper side of the upper individual plate 2a; these passages 13b adjoin apertures 15 which face towards the distribution or collection region and which extend at an angle to the plate plane. Hydrogen, for example, thus flows through the passages 13b and the apertures 15 from the through-opening 12b to the distribution or collection region on the upper side of the upper individual plate 2a, or in the opposite direction. The passages 13c enable air, for example, to pass between the through-opening 12c and the distribution or collection region, so that air enters the distribution or collection region on the underside of the lower individual plate 2b or is guided out therefrom. The associated apertures extending in the bead flank are not visible here.
The first individual plates 2a each also have a further sealing arrangement in the form of a perimeter bead 12d, which extends around the flow field 17 of the active region 18 and also around the distribution and/or collection region 20 and the through-openings 11b, 11c and seals these off with respect to the through-openings 11a, that is to say with respect to the coolant circuit, and with respect to the environment surrounding the system 1. The second individual plates 2b each comprise corresponding perimeter beads 12d. The structures of the active region 18, the distributing or collecting structures of the distribution and/or collection region 20 and the sealing beads 12a-d are each formed in one piece with the individual plates 2a and are integrally formed in the individual plates 2a, for example in an embossing, hydroforming or deep-drawing process. The same applies to the corresponding flow fields, distributing structures and sealing beads of the second individual plates 2b. Each sealing bead 12a-12d may have in cross-section at least one bead top and two bead flanks, but a substantially angular arrangement between these elements is not necessary; a curved transition may also be provided, e.g. beads which are arcuate in cross-section are also possible.
While the sealing beads 12a-12c have a substantially round course, which nevertheless depends primarily on the shape of the associated through-opening 11a-11c, the perimeter bead 12d has various sections that are shaped differently. For instance, the course of the perimeter bead 12d may include at least two wavy sections.
The two through-openings 11b or the fluid-guiding lines through the plate stack of the system 1 that are formed by the through-openings 11b are in each case in fluid connection with each other via the passages 13b crossing the sealing beads 12b, via the distributing structures of the distribution or collection region 20 and via the flow field 17 in the active region 18 of the first individual plates 2a facing towards the viewer of
In contrast, the through-openings 11a or the fluid-guiding lines through the plate stack of the system 1 that are formed by the through-openings 11a are in each case in fluid connection with each other via a cavity 19 which is surrounded or enclosed by the individual plates 2a, 2b. This cavity 19 serves in each case to guide a coolant through the bipolar plate 2, such as for cooling the electrochemically active region 18 of the separator plate 2. The coolant thus serves primarily to cool the electrochemically active region 18 of the separator plate 2. The coolant flows through the cavity 19 from an inlet opening 11a towards an outlet opening 11a. Mixtures of water and antifreeze are often used as coolants. However, other coolants are also conceivable. For better guidance of the coolant or cooling medium, channel structures are present on the inner side of the separator plate 2. These are not visible in
While
The first individual plate 2a may have a first sealing bead arranged around the through-opening 11 for sealing off the through-opening 11. The second individual plate 2b may accordingly have a second sealing bead arranged around the through-opening 11 for sealing off the through-opening 11. The first sealing bead and the second sealing bead may form the aforementioned bead arrangement 12 with the common sealing bead interior 24, which is fluidically connected to the through-opening 11 of the separator plate 2.
In the description below, also in relation to
The first sealing bead and the second sealing bead are typically formed on opposite sides of the separator plate 2 and usually point away from each other with their bead tops 23. The first sealing bead and the second sealing bead are usually designed as full beads and accordingly usually each comprise two bead flanks 21, 22. The bead flanks 21, 22 of the respective sealing beads are often connected by a bead top 23.
The bead flank 21 facing towards the through-opening 11 has a plurality of elevations 25 to enable a medium to pass through the bead flank 21, as well as conveying channels 27 adjoining said bead flank for conveying a medium to the bead flank 21. The through-opening 11 is in fluid connection with the bead interior 24 via the conveying channels 27 and the cutouts 25. The bead flank 22 facing away from the through-opening 11 likewise has elevations 25′ to enable a medium to pass through the bead flank 22.
The outer side of the bead arrangement 12, which faces away from the through-opening 11, is adjoined by conveying channels 26, which are in fluid connection with the bead interior 24 via elevations 25′. Here, the conveying channel 26 is designed such that a plurality of conveying channel sections open into a common distribution channel 29 extending substantially parallel to the bead arrangement 12, which distribution channel is likewise configured in the form of a bead and has apertures 15 arranged on the flank thereof facing away from the bead arrangement 12 and the through-opening 11. A medium guided in the media channel 11 can thus be guided through the bead arrangement 12 via the channels 27, the elevations 25, the bead interior 24, the elevations 25′, the channels 26, the distribution channel 29 and the apertures 15 and can be conveyed, for example, in a targeted manner into the active region 18 of the individual plate 2a or separator plate 2, as shown by the arrows in
A reversal of the flow direction with respect to the through-opening 11 is achieved, for example, by the opposite side of the separator plate 2, where the fluid is conveyed from the active region 18, through the bead arrangement 12, to the through-opening 11.
The entire conveying sequence consisting of conveying channel 27, elevation 25, bead interior 24, elevation 25′, optional conveying channel 26, optional distribution channel 29, and aperture 15, corresponds to a bead passage 13 as mentioned above.
In order to make the stack 2 of the separator plates of the system 1 as compact as possible, it is desirable to form the bead arrangement 12 and the other sealing beads 12a-d of the separator plate 2 in as shallow a manner as possible. However, the apertures 15 and elevations 25 in the bead flanks 21 may impair the stability and elasticity and thus the sealing effect of the bead arrangement 12. This could possibly be remedied by reducing the size of the apertures 15 and elevations 25. However, such a reduction in size would result in a likewise undesired reduction in the flow of medium through the bead arrangement 12.
In addition, the individual plates 2a, 2b of the separator plate 2 are often first embossed, hydroformed or deep-drawn before the apertures 15 are punched or cut into the individual plates. As a result, relatively complicated 3D cuts are required in order to form the apertures 15. Since the edges of the apertures 15 are sometimes arranged relatively high up in the stacking direction, there is also the risk that the MEA 10 resting on the bead top 23, such as the frame-like reinforcing layer or reinforcing frame of the MEA, will be damaged by sharp edges of the apertures 15.
The present disclosure has been conceived to solve, at least in part, the problems mentioned above.
Various embodiments of the present disclosure are shown in the groups of
The embodiments of
The separator plate 2 further comprises at least one through-opening 11 for the passage of a fluid, and a bead arrangement 12 arranged around the through-opening 11 for sealing off the through-opening 11, wherein a bead interior 24 of the bead arrangement 12 is fluidically connected to the through-opening 11 of the separator plate 2. Hereinbelow, the through-opening 11 can represent one of the through-openings 11a-11c mentioned above. Furthermore, the bead arrangement 12 can represent one of the sealing beads 12a-c. By means of the bead passages 30, the fluid can be conveyed from the through-opening, through the bead arrangement 12, to the active region 18, or from the active region 18, through the bead arrangement 12, to the through-opening 11.
The separator plate 2 additionally has at least one first aperture 35 formed in the first individual plate 2a, which aperture extends substantially parallel to a plate plane defined by the separator plate. In other words, a plane defined by the aperture 35, or more precisely by a circumferential edge 36 of the aperture 35, is substantially parallel to the plate plane of the separator plate 2.
The first aperture is therefore not formed in a bead flank 22 of the bead arrangement 12 that extends at an angle to the plate plane, or in a curved section of the separator plate, such as an end section of a conveying channel. Due to the fact that the plane defined by the aperture 35 is parallel to the plate plane, a simple 2D cut can be made when creating the aperture 35 or apertures 35. The parallel orientation of the aperture 35 also reduces the risk of damage to the reinforcing frame of the MEA 10.
In order that the aperture 35 of the first individual plate 2a is still fluidically connected to the bead arrangement 12, the separator plate 2 additionally comprises at least one conveying channel 40 formed in the second individual plate 2b, which conveying channel is arranged on a side of the bead arrangement 12 facing away from the through-opening 11. The conveying channel 40 formed in the second individual plate 2b opens into a region of the first individual plate 2a containing the first aperture 35. The conveying channel 40 formed in the second individual plate 2a also fluidically connects the bead interior 24 of the bead arrangement 12 to the first aperture 35 formed in the first individual plate 2a.
The conveying channel 40 may be formed or bounded by the plate material of the second individual plate 2b. The conveying channel 40 is usually integrally formed in the second individual plate 2b by hydroforming, roller embossing, vertical embossing and/or deep-drawing, and as such may be trough-shaped. It may be provided that, at least in some regions, the conveying channel 40 extends from the second sealing bead in the direction of the electrochemically active region 18. As shown in
It should be noted here that the fluidic connection of the bead interior 24 to the first aperture 35 by means of the conveying channel 40 may be established directly or at least indirectly. Between the conveying channel 40 and the bead interior 24, therefore, there may also be further channel sections or connection pieces which fluidically connect the conveying channel to the bead interior 24.
The conveying channel 40 may also comprise various sections 42, 44 with different orientations or directions of extension, cf. embodiments of
The conveying channel 40 may further comprise at least one secondary channel 44, for example a plurality of secondary channels 44. Hereinbelow, reference is made to a single secondary channel 44; of course, this may also mean a plurality of secondary channels 44. The secondary channel 44 may fluidically connect the primary channel 42 to the bead interior 24 and usually adjoins the bead flank 22 of the bead arrangement 12, or more precisely the bead flank of the second sealing bead formed in the second individual plate 2b. If the associated through-opening 11 is designed as an inlet opening, the primary channel 42 is thus fed by the secondary channels 44. Conversely, if the associated through-opening 11 is designed as an outlet opening, the primary channel 42 is a feed line for the secondary channels 44. Depending on the direction of flow of the fluid and the function of the through-opening 11, the primary channel 42 can be referred to as a distribution channel or collection channel. For instance, the sections 42 and/or 44 or the conveying channel 40 are lower than the bead arrangement 12, e.g. they project out of the plate plane by a smaller distance than the bead arrangement 12.
The secondary channel 44 may be arranged at an angle to the primary channel 42 and/or to the main direction of extension of the bead arrangement 12, for example at an angle α of at least 45°, for example at least 60°, for instance at least 75° and/or at most 135°, for example at most 120°, for example at most 105°. In one example, the secondary channel 44 extends substantially orthogonally to the primary channel 42 and/or to the main direction of extension of the bead arrangement 12. The secondary channel 44 usually extends from the bead arrangement 12 in the direction of the active region 18.
The first aperture 35 is usually spaced apart from the bead arrangement 12. The aperture 35 may be formed, for example, in a region of the first individual plate 2a that lies in a plate plane of the first individual plate 2a, cf. sectional views in
Alternatively, the first aperture 35 may be formed in an embossed region 37 of the individual plate 2a. Such a design is shown in the sectional views of
In the embodiment of
In the embodiments of
An orthogonal projection of the first aperture 35 perpendicular to the plate plane onto the second individual plate 2b may define a projection area, wherein the second individual plate 2b has at least part of the conveying channel 40 in the region of the projection area. This may be evident in a plan view of the first individual plate 2a and their first apertures 35, cf.
Although the separator plates 2 shown in
In some embodiments, the separator plate 2 comprises at least one conveying channel 50 formed in the first individual plate 2a, which conveying channel is arranged on a side of the bead arrangement 12 facing away from the through-opening 11 or on the side of the bead arrangement 12 facing towards the active region 18. The conveying channel 50 formed in the first plate 2a may be in direct or indirect fluid connection with the bead interior 24 of the bead arrangement 12.
The conveying channel 50 may be formed by the plate material of the first individual plate 2a. The conveying channel 40 is usually integrally formed in the second individual plate 2a by hydroforming, roller embossing, vertical embossing and/or deep-drawing and as such may be configured as a bead, such as a full bead. It may be provided that, at least in some regions, the conveying channel 50 extends from the first sealing bead in the direction of the electrochemically active region 18. The conveying channel 50 may adjoin the first sealing bead, such as a bead flank of the first sealing bead.
The conveying channel 50 may therefore comprise various sections 52 and/or 54 with different orientations or directions of extension, cf. embodiments of
The conveying channel 50 may comprise, for example, a single primary channel 52, cf.
The at least one aperture 35 may be formed in a flat section of the conveying channel 50 formed in the first individual plate 2a, for example in a flat top of the conveying channel. For instance, the aperture 35 may be formed in a flat section of the primary channel 52, for example in a top 38 of the primary channel 52.
In some embodiments (cf.
In some embodiments (cf.
The secondary channel 54 may be arranged at an angle to the primary channel 52 and/or to the main direction of extension of the bead arrangement 12 and/or to the edge 16 of the through-opening, for example at an angle β of at least 45°, for example at least 60°, at least 75° and/or at most 135°, for example at most 120°, at most 105°. In one example, the secondary channel 54 extends substantially orthogonally to the primary channel 52 and/or to the main direction of extension of the bead arrangement 12 and/or the edge 16 of the through-opening 11. The secondary channel 54 usually extends from the bead arrangement 12 in the direction of the active region 18.
The secondary channels 54 may extend so far in the direction of the first apertures 35 that, at least in some sections, such as with those regions in which they have their maximum height, they project between the first apertures or even to a greater distance away from the bead arrangement and thus can support the MEA reinforcing frame, so that a sufficient flow space to or from the aperture 35 to the active region 18 is ensured, cf.
It should be noted at this point that the conveying channel 50 and the channels 52, 54 are optional. The channels 50, 52, 54 are therefore not present in some embodiments, cf.
As already indicated above, conveying channels 27 may optionally be present on a side of the bead arrangement 12 facing towards the through-opening 11 (cf.
The conveying channels 27, 27a, 27b adjoin a bead flank 21 of the bead arrangement 12—or bead flanks of the first sealing bead and/or of the second sealing bead—and form a fluidic connection between the through-opening 11 and the bead interior 24. The feeding of a medium from the through-opening 11 to the bead arrangement 12 can thus take place by means of such conveying channels 27, 27a, 27b. Such conveying channels 27, 27a, 27b can also improve the discharging of the medium from the bead arrangement 12 to the through-opening 11.
Alternatively, as shown in
It is also possible to provide an aperture 35′ on the side of the sealing bead 12 facing towards the through-opening 11, too, as is the case in
It would also be possible to omit an aperture 35 on the side of the sealing bead 12 facing away from the through-opening 11; this may be advantageous if the medium, as is customary in the case of coolant for example, does not flow on an outwardly facing surface of the separator plate 2 in the active region 18, but instead flows in the interior between the individual plates 2a, 2b and therefore does not have to pass through any of the individual plates 2a, 2b on the side of the sealing bead 12 facing towards the active region 18. Features shown in connection with the apertures 35 shown in
The provision of secondary channels 44 may be advantageous if the conveying channels 27b are also arranged on the side of the bead arrangement 12 facing towards the through-opening 11. Accordingly, the provision of secondary channels 54 may also be advantageous if conveying channels 27a are also arranged on the side of the bead arrangement 12 facing towards the through-opening 11. By way of example, both channels 27a, 54 and 27b, 44 are provided on both sides of the bead arrangement 12 in the exemplary embodiments of
The provision of the primary channel 52 may be advantageous, for example, if embossed inner edges 16 of the through-opening 11 are present on the side of the bead arrangement 12 facing towards the through-opening 11, as is the case symmetrically in
The conveying channels 40, 50 of the individual plates 2a, 2b may overlap at least in some regions and at these points, they can together form a conveying channel 60 of the separator plate 2. Overlapping primary channels 42, 52 of the individual plates 2a, 2b may therefore be parts of a primary channel 62 of the separator plate 2. In some embodiments, a secondary channel 64 of the separator plate 2 is provided, which is formed by overlapping secondary sections 44, 54 of the individual plates 2a, 2b, cf.
The secondary channels 44, 54 of the individual plates are sometimes offset from each other, so that they do not form a common secondary channel 64, but instead form spatially separate channel sections, cf. for example
The through-openings 11 of the individual plates 2a, 2b each optionally have embossed inner edges 16 extending therearound, which edges point away from each other and/or are spaced apart from each other, cf.
In the exemplary embodiment of
The first individual plate 2a may sometimes also have embossed structures 39, which are spaced apart from the bead arrangement 12 and the apertures 35. The embossed structures 39 are shown, for example, in
The conveying channel 27b formed in the second individual plate 2b and the secondary channel 44 often have an equal height, measured perpendicular to a flat surface plane (plate plane) of the separator plate 2b or the second individual plate 2b, cf.
In the embodiment of
The conveying channel 27a formed in the first individual plate 2a and the secondary channel 54 often have an equal height, measured perpendicular to a flat surface plane (plate plane) of the separator plate 2 or the second individual plate 2b, cf.
In a section located between the through-opening 11 and the active region 18, the bead arrangement 12 may have a periodic course, such as a wavy course with concave and convex sections, cf.
The apertures 35 may face towards convex and/or concave sections of the bead arrangement 12. Each aperture 35 may be arranged between two adjacent secondary sections 54 or embossed structures 39. The apertures 35 may be spaced apart from each other at regular intervals, cf.
The exemplary embodiments of
One aperture 35 may be fluidically connected to two conveying channels 40 that terminate in the vicinity thereof, as shown in
A group of two apertures 35 may be fluidically connected via a short conveying channel 40 or 42 to a terminating conveying channel 54, as shown in
It is clear to a person skilled in the art that individual features of
It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. Moreover, unless explicitly stated to the contrary, the terms “first,” “second,” “third,” and the like are not intended to denote any order, position, quantity, or importance, but rather are used merely as labels to distinguish one element from another. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.
As used herein, the term “approximately” or “substantially” is construed to mean plus or minus five percent of the range unless otherwise specified.
The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2022 101 861.8 | Apr 2022 | DE | national |
