Separator plates and bipolar plates for electrochemical systems

Abstract

The invention relates to a separator plate and a bipolar plate for an electrochemical system, respectively. The electrochemical system may particularly be a fuel cell system, an electrochemical compressor, an electrolytic cell, or a redox flow battery. Also disclosed is an electrochemical system having a plurality of such separator plates.

Description

Technical Field

[0001] This invention relates to separator plates and bipolar plates used in electrochemical systems. These electrochemical systems may in particular be fuel cell systems, electrochemical compressors, electrolyzers, or redox flow batteries. An electrochemical system having multiple such separator plates is also disclosed. Background Technology

[0002] Known electrochemical systems of this type typically comprise an electrochemical cell stack, with each cell separated from the others by bipolar plates. In the context of such stacks, two monolayer separator plates are typically connected, and in particular joined together, to form a bipolar plate, wherein each separator plate forms a single layer of the bipolar plate. These separator plates can be joined together by material bonding, for example, through one or more welded joints, particularly through one or more laser-welded joints.

[0003] Separator plates or bipolar plates can be used, for example, for electrical contact of the electrodes of individual electrochemical cells (e.g., fuel cells) and / or for electrical connection of adjacent cells (cells in series).

[0004] Separator plates or bipolar plates may each have or be configured to supply one or more media and / or remove reaction products, for example, to an electrochemical cell arranged between adjacent separator plates or bipolar plates. In particular, cooling fluid can be guided through the gaps between the individual plates of the bipolar plates by means of these structures. These structures may, for example, include alternating sequences of fins and channels. Thus, the media may be a fuel (e.g., hydrogen or methanol), a reaction gas (e.g., air or oxygen), or a cooling fluid. Within the scope of this disclosure, the terms "media" and "fluid" may be used synonymously.

[0005] In addition, each bipolar plate typically has at least one through-opening through which a medium can be guided into or out of an electrochemical cell or membrane electrode assembly (MEAs) arranged between adjacent bipolar plates in the stack.

[0006] From such a through-opening, various fluids are guided by the aforementioned structure into the respective first distribution regions, and from there into a flow field opposite the active region of the battery or MEA. After flowing through the active region, the fluid is again conveyed to the outlet-through-opening via a second distribution region, also known as a collection region. An example of this can be found in DE 202016 107 302 U1.

[0007] It is known that a first fluid, such as fuel, is guided at the first outer side of the bipolar plate, i.e., the outer side of the first separator plate, and a second fluid, such as a reactant gas, is guided at the second outer side of the bipolar plate, opposite to the first outer side, i.e., the outer side of the second separator plate. However, in the internal space defined by the inner side of the separator plates, the opposite flow is typically guided by a cooling fluid. The structures guiding the fluid at the corresponding outer sides of the separator plates form complementary structures on their inner sides that guide the cooling fluid.

[0008] However, it has been shown that the performance of such electrochemical systems can still be optimized. Thus, for example, the fluid guide portion penetrating between the opening and the flow field still occupies a significant area percentage on each side of the bipolar plate. This area percentage cannot be used as the active region of the battery and therefore does not directly contribute to its performance. Summary of the Invention

[0009] Therefore, one object of the present invention is to improve the performance of electrochemical systems having multiple such separator plates and bipolar plates.

[0010] This objective is achieved through the subject matter of the independent claims. Advantageous modifications will be given in the dependent claims, as well as in this specification and the accompanying drawings.

[0011] Accordingly, a separator plate for an electrochemical system is proposed, wherein, for example, the separator plate can form a single-layer bipolar plate, or can be combined with another separator plate to form a double-layer bipolar plate. The separator plate has:

[0012] - At least one first through opening for guiding a first reactive fluid through a separator plate; at least one second through opening for guiding a second reactive fluid through a separator plate; and at least one third through opening for guiding a cooling fluid through a separator plate;

[0013] - On the outside of the separator plate: at least one distribution area, flow field, and at least one branch sub-channel;

[0014] The distribution area connects the first through opening to the main region of the flow field in a fluid-conducting manner.

[0015] Among them, the secondary channel of this branch:

[0016] - Connect the first through opening to the secondary region of the flow field in a fluid-conducting manner, and

[0017] - At least segmentally extending along the periphery of the back-distribution area of ​​the first and / or second and / or third through-opening;

[0018] This sub-region has multiple flow field sub-channels and ribs formed between every two flow field sub-channels.

[0019] These ribs form complementary cooling fluid secondary channels on the inner side of the separator plate.

[0020] Wherein, the branch secondary channel and / or the flow field secondary channel has at least one segmental protrusion at the bottom of the channel, and

[0021] The at least one protrusion forms part (a section) of the fluid connection between at least one cooling fluid secondary channel and the third through opening on the inner side of the separator plate.

[0022] According to the invention, through branched secondary channels, a surface region of the separator plate is used to supply fluid to the flow field, this region being located outside both the conventional distribution region and the distribution region according to the invention. Thus, a fluid supply path for the flow field, more precisely for its secondary region, previously unused, is provided. Furthermore, according to the invention, at least partial sections of the branched secondary channels can extend within the region of the separator plate, these regions serving as such an additional fluid supply path without significantly impairing other structural features or functions of the separator plate.

[0023] By supplying at least a portion of the fluid to the flow field through branched secondary channels, it is possible to reduce the number of channels and / or the area percentage of the distribution region compared to existing methods. This allows for an expansion of the flow field, thereby improving the performance of the electrochemical system.

[0024] Another advantage is that the branch secondary channels can be traversed continuously, at least in sections, without fluid buildup and / or stagnation. Otherwise, the fluid could freeze. However, regions of fluid buildup with such characteristics do exist in existing schemes.

[0025] For example, existing designs have gaps between adjacent protrusions (grooves), which can also be filled by fluid from the first through opening. Fluid can flow in but cannot flow out, thus remaining stagnant in the gaps. The secondary channel according to the invention can also contain such gaps, but provides the possibility of discharge through connection with the flow field, enabling flow through the gaps.

[0026] Furthermore, the multiple flow field sub-channels can advantageously provide a throttling effect. In particular, by distributing the fluid flow from the branch sub-channels to the multiple flow field sub-channels (or conversely, from the flow field sub-channels to the branch sub-channels), the fluid flow can be purposefully throttled. This can limit the risk of significant oversupply of the branch sub-channels, and therefore the flow field sub-channels, relative to other channels in the flow field and / or distribution area. As will be further explained below, at least one protrusion can also provide this throttling effect.

[0027] At least one protrusion according to the invention advantageously enables reliable and large-area cooling of the secondary region of the flow field. This is because it has been shown that without such a protrusion, the cooling fluid flow inside the separator plate, particularly within the internal space of the bipolar plate, cannot reach all areas inside the secondary region of the flow field. In particular, not all inner channels formed in principle by the ribs therein (see the claimed cooling fluid secondary channels) can be supplied with cooling fluid. For example, without such a protrusion, the cooling fluid (small) path through the outer channels of the separator plate (which in turn form inner ribs) may be blocked or at least significantly reduced before the cooling fluid (small) path reaches the inner side of the secondary region of the flow field. Unlike the secondary region, whether in the distribution region or the main region of the flow field, it is preferable not to provide a protrusion at the bottom of the channels in the main region, since there the flow field channels are directly supplied via branch channels. Therefore, the channels in the distribution region and the main region of the flow field, particularly all channels and / or their bottoms, may be without protrusions. The bottoms of the channels in the distribution region and the main region of the flow field, particularly all channels, can be on a reference plane ( The protrusion extends within the plane of the reference plane and / or is at a distance from the plane of the reference plane that is less than the protrusion disclosed herein.

[0028] The through openings can be configured according to existing schemes. The first to third through openings can be located between the distribution area closest to them and the outer edge of the separator plate. The first to third through openings can be arranged successively to each other transversely to the main flow axis described below, and / or side by side, preferably at a certain distance from each other. In a manner known per se, the first to third through openings can be sized differently, particularly in terms of their area. Additionally or alternatively, their centroids can be located at different positions along the main flow axis.

[0029] The first and third through openings can accommodate the second through opening between them, for example, when viewed transversely to the main axis.

[0030] The separator plate may have distribution areas on both sides of the flow field, wherein an arrangement of (multiple) through openings disclosed herein and, preferably, secondary channels disclosed herein, may be provided between each distribution area and the outer edge of the separator plate closest to it.

[0031] The first and second through openings can be through openings for guiding fluid on the outer side of the separator plate and / or bipolar plate, respectively. The designation of the outer or inner side of the separator plate is assigned to each surface of the separator plate in such a way that it corresponds to its function in the bipolar plate.

[0032] In the case of a bipolar plate, the first separator plate disclosed herein can specifically form a cathode plate, and / or may guide oxygen or air as a first fluid at its outer side. The second separator plate of the bipolar plate can form an anode plate, and / or may guide hydrogen as a second fluid at its outer side. However, alternatively, the first separator plate can also be configured as an anode plate, and / or guide hydrogen as a first fluid at its outer side. Then the second separator plate can be configured as a cathode plate, and / or may guide oxygen or air as a second fluid at its outer side.

[0033] The secondary branch channel may be fluid-conductingly connected to the first through opening, for example, by means of a through portion included therein or connected thereto, passing through a sealing flange surrounding the through opening. In particular, the secondary branch channel and / or the secondary region of the flow field may not be fluid-conductingly connected to the first through opening via a bypass path through the distribution region. For example, fluid exiting the first through opening may be diverted into the secondary branch channel and the distribution region.

[0034] In the case of opposite flow directions, the first through opening can be supplied simultaneously by the sub-branch channel on one hand and by the distribution region on the other. The volume proportion of fluid entering or leaving the sub-branch channel can be less than the corresponding volume proportion entering or leaving the distribution region. In particular, the volume proportion of the sub-branch channel can be less than 10% of the volume proportion guided by the distribution region, especially less than 8%, preferably less than 5%.

[0035] The secondary branch channel can extend segmentally (sectionally) away from the distribution area from its fluid-conducting connection to the first through opening. In particular, the secondary branch channel can extend segmentally towards the outer edge of the separator plate. Alternatively or additionally, it can extend segmentally towards the side of the first through opening away from the distribution area.

[0036] The secondary branch channel may extend at least segmentally at an angle relative to the main flow axis, particularly substantially transversely to it. The main flow axis may be an axis along which the fluid is guided in the flow field (particularly in the secondary and main regions). The main flow axis may be straight. In cases where the channel in the flow field is not straight but, for example, wavy, the main flow axis may extend parallel to the average orientation of the channel and / or the central axis of the wavy shape and / or define such an average orientation or central axis. Additionally or alternatively, the main flow axis may extend parallel to the axis of symmetry and / or longitudinal axis of the flow field, or form such an axis.

[0037] The secondary branch channel may optionally extend along multiple through openings. Specifically, it may extend between the peripheral segment of the opposite distribution region of the second and / or third through opening and the outer edge of the separator plate closest to it, and / or extend in a direction toward the second and / or third through opening. This indicates that the first through opening and the other through openings are preferably positioned close to different long sides of the separator plate. These long sides can extend along, and in particular parallel to, the main flow axis that passes through the flow field.

[0038] The flow field can have multiple fluid channels in a manner known per se. These fluid channels can extend adjacent to each other, particularly in a straight line and parallel to each other and / or in a wavy pattern. Here, the fluid channels preferably extend along the main flow axis of the flow field described above.

[0039] For example, the flow field may be characterized in that all the ribs and channels it includes are straight and extend parallel to each other and parallel to the main flow direction of the cooling fluid through the flow field, particularly as defined by the main flow axis. Alternatively, however, the ribs and channels may be wavy and extend adjacent to each other with the same waveform and along the main flow axis.

[0040] Additionally or alternatively, the flow field may be characterized in that it is located within the reinforcing edge of the MEA of the battery, and is particularly at least segmentally surrounded and / or encircled by it. However, preferably, the active region of the MEA itself, particularly in the form of the electrolyte membrane of the MEA, is not opposed to the reinforcing edge of the MEA itself. Exemplary reference is made to DE 20 2020106 459 U1, particularly to the figure marked 3B, which illustrates an MEA with a reinforcing edge surrounding the active region of the MEA.

[0041] Fluid flow through the corresponding conduction via the through-opening can occur, in particular, perpendicular to the plate plane and / or reference plane of the separator plate. In a manner known per se, the reference plane of a single-layer separator plate can be defined, for example, by the edge of the separator plate or by those flat areas of the separator plate that are not deformed by the embossing or deep drawing process used to form the rib-channel structure or flanges described herein. On one hand, the reference plane can extend in the neutral plane of the corresponding segment of the plate. On the other hand, the surface of the relevant segment of the plate can also be considered as the reference plane. However, in the latter consideration, it should be noted that in the case of double-layer bipolar plates and when considering distance, etc., only the material thickness of one of the two observed plates is taken into account.

[0042] In principle, more than two flow field secondary channels can be set up, and a rib can be formed between every two adjacent flow field secondary channels. If only exactly two flow field secondary channels are set up, it should be understood that there is only one single rib located between these two flow field secondary channels.

[0043] The inner fluid connection formed by the protrusion may specifically include or define a section of the cooling fluid (small) path connecting the third through opening and at least one cooling fluid secondary channel. Other sections of this cooling fluid (small) path may be formed, for example, by inner channels defined by ribs in the distribution area. It may be specified that the protrusion, or possibly multiple such protrusions, achieves a unique fluid connection between the third through opening and at least one cooling fluid secondary channel. The cooling fluid secondary channel may be supplied with cooling fluid, particularly alone or primarily, from the protrusion, and especially from the fluid connection defined internally by the protrusion. However, it cannot be supplied with cooling fluid directly from the cooling fluid distribution area and / or cannot directly transition to such an area.

[0044] According to an improvement, the at least one protrusion is formed in one of the flow field sub-channels, and the distance from the protrusion to the closest fluid inlet region and / or fluid outlet region of the flow field, measured along the main flow axis of the flow field sub-channel, is at most 5 cm, particularly at most 2 cm, particularly at most 1 cm, and / or at most 10% of the total length of the flow field sub-channel, particularly at most 6%.

[0045] Therefore, the protrusion can be correspondingly located near the end region of the secondary flow channel viewed along the main flow axis, where the end region corresponds to the fluid inlet region and / or fluid outlet region. For example, the transition from the transition region, which will be considered in more detail here, to the actual flow field can be regarded as the fluid inlet region and / or fluid outlet region. Alternatively, the line closest to the adjacent through opening, with the minimum rib height of the two plates on their outer sides, can be regarded as the fluid inlet region and / or fluid outlet region, even if this line may belong to the transition region or distribution region.

[0046] This arrangement of protrusions enables comprehensive cooling in the secondary region of the flow field—a cooling that also extensively cools the electrochemically active regions of the flow field within the secondary region. Figuratively speaking, viewed in the flow direction of the secondary channel, inner cooling can thus begin earlier and / or be maintained shortly before the end of the secondary channel.

[0047] The main flow axis of the secondary flow channel can be defined similarly to and / or parallel to the main flow axis of the flow field. It can correspond to the longitudinal axis of the secondary flow channel.

[0048] According to one improvement, the separator plate has a second branch sub-channel that fluidly connects the first through opening to a sub-region of the flow field. This second distribution sub-channel preferably extends at least segmentally (regionally) along the peripheral section of the second and / or third through opening toward the distribution region. This thus creates another fluid connection between the first through opening and the flow field outside the distribution region.

[0049] According to one improvement, at least one protrusion has a length in the extension direction of the secondary flow channel that is at most 5% of the length from the shortest branch secondary channel to the boundary of the flow field or the secondary flow channel; and / or the at least one protrusion extends along the main flow axis of the secondary flow channel in the extension direction of the secondary flow channel for a length of at most 2 cm, particularly at most 1 cm or at most 0.5 cm. This limits any influence of the protrusion on the flow of the secondary flow channel. It has been shown that using the given values, the desired cooling effect can be reliably achieved and / or enhanced without unduly obstructing the flow of the secondary flow channel.

[0050] According to an improvement, the average height of at least one protrusion, measured perpendicular to the reference plane, is at most 80%, preferably at most 60%, of the maximum height of the structure defining the branch sub-channel or flow field sub-channel in which the at least one protrusion is constructed, measured perpendicular to the reference plane. If the protrusion is formed in the cathode plate, the measured average height of the at least one protrusion is preferably at most 50% of the defined structure. Examples of such structures will be further described below. In this embodiment, the desired effect of the at least one protrusion can also be reliably achieved without unduly obstructing the flow in the sub-region of the flow field.

[0051] According to one improvement, at least one protrusion is formed in one of the flow field sub-channels, and the two ribs defining the flow field sub-channel are connected to each other. In this way, a reliable and compact internal fluid connection can be provided for the cooling fluid sub-channels formed by these ribs.

[0052] According to an improvement, one of the ribs in the secondary region of the flow field and / or the cooling fluid secondary channel formed thereon on its inner side is configured to exchange cooling fluid with the cooling fluid secondary channel of the opposing separator plate. Specifically, they can jointly define a cooling fluid (small) path, and / or define a segment of this (small) path by clamping the corresponding gap within the double-layer bipolar plates. In this way, particularly comprehensive cooling fluid guidance along the inner side of the secondary region can be ensured, thereby ensuring correspondingly significant cooling.

[0053] According to an improvement, a protrusion is formed in one of the flow field sub-channels, and the ribs defining the flow field sub-channels are connected to the structure defining the main region of the flow field, wherein cooling fluid can be guided at the inner side of the structure.

[0054] In particular, protrusions can be formed in the secondary flow channel closest to and directly adjacent to the main flow region. This secondary flow channel can extend, for example, between the ribs defining the channel in the secondary region and the structure defining the main region. This positioning of the protrusion ensures a compact and efficient supply of cooling fluid to the inner side of the secondary region, since the structure defining the main region typically guides the cooling fluid inwards.

[0055] According to one variation, the structure defining the main region is the outermost rib of the main region. The outermost position can exist, in particular, transverse to the main flow axis passing through the flow field, and / or defined along the corresponding transverse axis.

[0056] It should be noted that the outermost rib or structure generally defining the main region of such a main region cannot be classified as a sub-region. Typically, the outermost rib and / or structure generally defining the main region defines only a single flow field sub-channel, particularly the flow field sub-channel directly adjacent to it. Therefore, unlike the ribs of the sub-regions of the flow field, the outermost rib or defining structure of the main region is usually not formed between two flow field sub-channels. Therefore, it typically does not form any rib of a sub-region of the flow field in the sense of this disclosure.

[0057] A defining element may be arranged between the secondary region of the flow field and the outer edge of the separator plate. Such a defining element defines only a single secondary flow field channel, particularly the secondary flow field channel furthest from the main region. This defining element typically does not form any ribs in the secondary region of the flow field in the sense of this disclosure.

[0058] As mentioned earlier, exactly two flow field secondary channels can be provided, with only a single rib formed between these two secondary channels. The remaining boundaries can be defined either by the outermost rib of the main region and / or by a general structure defining the main region, or by defining elements. Unlike the boundary between the rib and the outermost rib of the main region, no protrusions should be arranged between the rib and the defining elements.

[0059] According to one improvement, the sub-region includes at least three ribs and at least two flow field sub-channels, which are defined at least segmentally or at least partially by two corresponding adjacent ribs. Here, for example, the corresponding two adjacent ribs are connected to each other by at least one segmental protrusion at the bottom of the flow field sub-channel they define. The at least two flow field sub-channels may be adjacent to each other and separated from each other by a common rib.

[0060] Defining a protrusion at least segmentally or at least partially by ribs can include, for example, the ribs defining only one side and / or only a peripheral segment of the protrusion, particularly its profile. For example, two opposing sides of the protrusion can be defined by ribs. Conversely, two other opposing sides of the protrusion can transition into a flow field sub-channel that includes the protrusion, particularly into the bottom of its channel.

[0061] By incorporating multiple protrusions, the cooling fluid can be distributed transversely to the main flow axis within the secondary region. Therefore, the cooling fluid can reach not only the innermost cooling fluid channels adjacent to the main flow region, but also, conversely, the outermost innermost cooling fluid channels within the secondary region when viewed transversely to the main flow axis.

[0062] Typically, any channel disclosed herein can form a recessed area relative to the adjacent ribs, these areas being configured to guide fluid. The bottom of each channel can form a surface area with minimum height in at least selected sub-regions of the separator plate. Conversely, the rib surface can form a surface area with maximum elevation in at least selected sub-regions of the separator plate. The respective sub-regions of the aforementioned separator plate can each cover several square centimeters, particularly greater than 10 cm. 2 These can include both multiple ribs and multiple channels. The rib surfaces and the bottoms of each channel can be connected via sidewalls (flankens), which can optionally belong to either the ribs or the channels. Here, the height can be measured orthogonally to the reference plane of the separator plate.

[0063] Additionally or alternatively, the rib surface may form contact areas (equipment areas) for other components of the electrochemical system, particularly for MEA, PTL and / or GDL.

[0064] Combining the several possible protrusions defined above, an improved provision stipulates that each of at least one protrusion is distributed along a common axis within the secondary flow channel, which extends orthogonally to the main flow axis of the secondary flow channel and / or the flow field. In other words, the protrusions of the secondary flow channel can be arranged successively and / or flush with each other along the common axis. Here, this axis can be, in particular, straight. Furthermore, when more than two corresponding protrusions are provided, their distribution along this axis can be specifically arranged. In this way, the cooling fluid can also be allowed to flow a short distance in the cooling fluid channel inside the secondary region, away from the main flow field. This reduces the loss of the cooling capacity of the cooling fluid (i.e., its premature heating), which typically increases with the increase of the length of the cooling fluid flow path.

[0065] According to one improvement, at least one protrusion within the secondary flow channel has a main flow axis extending relative to the main flow axis of the secondary flow channel at an angle of less than 60° or less than 45°. Specifically, the main flow axis of the secondary flow channel in which the protrusion is formed can be considered here. The main flow axis can be an axis along which the cooling fluid is primarily guided on the inner side of the protrusion. In particular, it can be the longitudinal axis of the protrusion and / or the longitudinal axis of the (small) path or cooling fluid path segment defined therein. For example, this axis can correspond to or define a shortest flow path along which the cooling fluid can flow on the inner side of the protrusion.

[0066] By using appropriately tilted protrusions, or more precisely, by tilting the main flow axis of the protrusions relative to the main flow axis of the secondary flow channels, the cooling fluid can be guided inwards without turbulence and / or via the shortest possible flow path. This, in turn, enhances the cooling capacity of the secondary regions of the flow field.

[0067] According to one improvement, in the presence of multiple possible protrusions, particularly as discussed in the context of the aforementioned embodiments, the inner flow cross-section of a protrusion farther from the main region is smaller than the inner flow cross-section of the corresponding other protrusion. The latter can then be arranged closer to the main region accordingly. Here, a corresponding distance to the main region along an axis that extends transversely to the main flow axis according to any variation disclosed herein can be taken into consideration.

[0068] The inner flow cross section can be formed, in particular, by a cooling fluid (small) path or a cooling fluid (small) path segment formed on the inner side of the protrusion. In particular, the inner cooling fluid (small) path or cooling fluid (small) path segment can be shaped to be complementary to the protrusion.

[0069] The flow cross-section decreases with increasing distance from the main region, which helps to maintain a substantially constant pressure loss of the cooling fluid despite the diversion of the cooling fluid in all (small) path sections. Therefore, the inner flow velocity (rate) can, for example, remain substantially constant compared to the protrusion or its flow cross-section located closer to the main region, or the decrease in the flow velocity (rate) can be limited to an acceptable level.

[0070] According to one improvement, the separator plate includes a continuously recessed transition region comprising end sections transitioning to branch secondary channels in the flow field and end sections of the distribution region.

[0071] The average channel height measured perpendicular to the reference plane in this flow field is h1, and the maximum channel height measured perpendicular to the reference plane in the transition region is h. max , where h max≤0.95·h1.

[0072] The recessed transition region allows for the accommodation of reinforced edge regions of the MEA adjacent to the separator plate. This enables uniform or targeted lamination of the membrane, particularly in the active regions of the relevant electrochemical cell.

[0073] For example, the transition region of the depression may belong to the distribution region, unless otherwise stated or obvious herein.

[0074] According to one improvement, at least one protrusion is formed within a section of the branch sub-channel extending in the transition region. Similar to the aforementioned implementation regarding the positioning of the protrusion, this allows for the earlier introduction and / or later exit of cooling fluid on the inner side in terms of the flow path through the sub-region, thereby enabling the sub-region to be cooled over a long distance (segment) on the inner side, and thus is correspondingly effective.

[0075] According to an improvement, for example, the branched subchannel branches into multiple channel segments in the transition region, each channel segment being correspondingly separated by a rib segment, wherein the channel segment transitions into the flow field subchannel, and the rib segment transitions into the ribs of the sub-region, wherein at least one protrusion is formed at least segmentally in one of the channel segments and connected to a structure defining the distribution area, on the inner side of which cooling fluid can be guided. The protrusion may be defined at least segmentally or at least partially by the structure defining the distribution area. Further at least segmental or at least partial (proportional) definition of the protrusion may be achieved, for example, by one of the rib segments.

[0076] According to an improvement, the length of at least one protrusion measured along the main flow axis of the secondary flow channel is less than the length of the transition region measured along the main flow axis.

[0077] According to an improvement, a second allocation area sub-channel is formed, which:

[0078] - Connect the first through opening to the secondary region of the flow field in a fluid-conducting manner, and

[0079] - At least segmentally extending along the periphery of the second and / or third through opening toward the distribution area.

[0080] The present invention also relates to a bipolar plate for an electrochemical system, comprising a first separator plate according to any aspect disclosed herein and a second separator plate that may also be configured according to any aspect disclosed herein. Here, the inner sides of the first and second separator plates face each other, such that cooling fluid can be guided between them.

[0081] An electrochemical system having multiple separator plates according to any of the aspects described herein is also disclosed. Attached Figure Description

[0082] The invention will now be described with reference to the illustrative accompanying drawings. In all the drawings, the same reference numerals may be used for features that are identical or functionally identical. If the drawings show multiple instances of a feature, for clarity, only the selected instance may be labeled with the reference numerals that are in principle assigned to that feature.

[0083] Figure 1 An electrochemical system with multiple stacked bipolar plates is illustrated in a three-dimensional diagram.

[0084] Figure 2 A stereoscopic illustration shows something similar to Figure 1 The system has two bipolar plates with a membrane electrode assembly (MEA) arranged between the separator plates.

[0085] Figure 3 This is an illustration of fluid guidance along a sub-region of a bipolar plate according to an embodiment of the invention, wherein the bipolar plate comprises two separator plates formed according to the invention.

[0086] Figures 4 to 12 Detailed views of the separator plate according to other embodiments of the present invention are shown respectively.

[0087] Figure 13 A cross-sectional view of a bipolar plate according to an embodiment of the present invention is shown. Detailed Implementation

[0088] Figure 1 An electrochemical system 1 of the type presented herein is shown, having multiple identical metal bipolar plates 2, each bipolar plate being formed by two separator plates joined together. The bipolar plates 2 are arranged in a stack 6 and stacked along the z-direction 7. The bipolar plates 2 of the stack 6 are clamped between two end plates 3, 4. The z-direction 7 is also referred to as the stacking direction.

[0089] In this example, System 1 is a fuel cell stack. In the stack 6, each pair of adjacent bipolar plates 2 clamps an electrochemical cell between them, for example, an electrochemical cell used to convert chemical energy into electrical energy. To form the electrochemical cell of System 1, membrane electrode assemblies (MEAs) 10 (see below) are correspondingly arranged between adjacent bipolar plates 2 in the stack 6. Figure 2 MEA 10 typically contains at least one membrane, such as an electrolyte membrane. Additionally, gas diffusion layers (GDLs) may be disposed on one or both surfaces of the MEA.

[0090] In alternative embodiments, System 1 can also be configured as an electrolyzer, compressor, or redox flow battery. The electrolyzer can be, for example, a polymer electrolyte membrane (PEM) electrolyzer for hydrogen production, or an anion exchange membrane (AEM) electrolyzer for CO2 conversion. Separator plates can also be used in these electrochemical systems. In the case of an electrolyzer, a single, single-layer separator plate can be used as a bipolar plate. The structure of these separator plates can correspond to the separator plate structure described in detail herein, even in the case of an electrolyzer, electrochemical compressor, or redox flow battery, the medium guided on or through the separator plate can be distinguished accordingly from the medium used in a fuel cell system.

[0091] The z-axis 7, x-axis 8, and y-axis 9 together form a right-handed Cartesian coordinate system. The bipolar plates 2 define plate planes that are parallel to the xy plane and therefore perpendicular to the stacking direction (z-axis 7). The end plates 4 have multiple media interfaces 5 through which media can be supplied to and discharged from the system 1. These media supplied to and discharged from the system 1 may include, for example, fuels such as molecular hydrogen or methanol; reaction gases such as air or oxygen; reaction products such as water vapor or lean fuel; or cooling fluids such as water and / or ethylene glycol.

[0092] Figure 2 Two adjacent bipolar plates 2 are shown in three dimensions, which can be included in... Figure 1 In the electrochemical system of type 1, the bipolar plate 2 corresponds to an example in the prior art. However, the characteristics and features described below are equally applicable to, or may be provided at, the bipolar plates and / or separator plates disclosed herein according to the invention, unless otherwise stated or clearly visible.

[0093] Figure 2 A known membrane electrode assembly (MEA) 10 is also shown arranged between these adjacent bipolar plates 2, wherein the MEA 10 is in Figure 2 Most of the bipolar plate 2 is obscured by the bipolar plate facing the observer. The bipolar plate 2 is formed by two separate, single-layered separator plates 2a and 2b bonded together using a material bonding method. Figure 2 In this configuration, only separator plate 2a facing the observer is visible, obscuring the other separator plate 2b. Separator plates 2a and 2b can each be made of sheet metal, such as stainless steel. For example, separator plates 2a and 2b can be welded together, for example, by laser welding, or only joined when stacking the stacks. Especially... Figure 2 The configuration of the structure guiding the fluid outward from the observer in the middle separator plate 2a may differ from the structure according to the invention shown in the other figures below.

[0094] Separator plates 2a and 2b have through openings aligned with each other, which form through openings 11a, 11b, and 11c of bipolar plates 2. When multiple bipolar plates 2 are stacked, the through openings 11a, 11b, and 11c form guides (channels) extending through the stack body 6 in the stacking direction 7 (see...). Figure 1 Typically, each guide (conduit) formed by the through openings 11a, 11b, and 11c is fluidly connected to one of the ports 5 in the end plate 4 of system 1. For example, cooling fluid can be introduced into or out of the stack 6 via the guide formed by the through opening 11a. In contrast, the guides formed by the through openings 11b and 11c can be configured to supply fuel and reaction gases to the electrochemical cells of the fuel cell stack of system 1, and to remove reaction products from the stack 6.

[0095] To seal the through openings 11a, 11b, and 11c relative to the interior of the stack 6 and relative to the surrounding environment, the separator plate 2a facing the observer has a corresponding sealing device (sealing structure) constructed as sealing protrusions (sealing grooves) 12a, 12b, and 12c. These sealing protrusions are arranged around the through openings 11a, 11b, and 11c, respectively, and completely surround the through openings 11a, 11b, and 11c. The second separator plate 2b is located on the back side of the bipolar plate 2. Figure 2 The rear side of the observer also has corresponding sealing flanges 12a, 12b, 12c for sealing the through openings 11a, 11b, 11c (not shown). Alternative sealing systems, such as elastomeric seals, may also be used.

[0096] Adjacent to the electrochemically active region of the MEA, the separator plate 2a facing the observer has a flow field 17a on its outer side facing the observer. This flow field has a structure for guiding the reaction medium along the outer side of the separator plate 2a. These structures are... Figure 2 The separator plate is constructed with multiple ribs and channels extending between and defined by the ribs. For simplicity, the region of the separator plate opposite the electrochemically active region of the MEA is also referred to as the active region 18, which is essentially formed by the flow field 17a. On the observer-facing side of the bipolar plate 2, the separator plate 2a also has two distribution regions 20. The distribution regions 20 each include structures configured to: distribute the medium introduced into the distribution region 20 from the first through-opening 11b via the flow field 17a to the electrochemically active region of the MEA; or collect or concentrate the medium flowing from the electrochemically active region of the MEA or from the flow field 17a to the second through-opening 11b. In the latter case, the collecting distribution region 20 can also be referred to as a collecting region. The fluid guiding structure of the distribution region 20 is... Figure 2 The middle part is also composed of ribs and channels extending between the ribs and defined by the ribs.

[0097] Despite Figure 2 Not shown separately, but formed and / or included between the separator plates 2a and 2b, the cooling fluid distribution structure 19 also has a distribution region 20c, which overlaps with the distribution regions 20a and 20b of the individual plates 2a and 2b. This cooling fluid distribution structure 19 is fluidly connected to a flow field 17c, which overlaps with or is sandwiched between the flow fields 17a and 17b on the outer sides of the separator plates 2a and 2b, or the cooling fluid distribution structure 19 includes the flow field 17c. The rib-channel structure on the outer sides of the separator plates 2a and 2b forms a complementary rib-channel structure on the corresponding inner side, thus forming a complementary rib-channel structure of the cooling fluid distribution structure 19.

[0098] The two through openings 11b, or the guide portions of the plate stack formed by the through openings 11b, pass through the through portion 13b in the sealing protrusion 12b, through the distribution structure of the distribution area 20, and through the direction towards Figure 2 The flow field 17a of the separator plates 2a is fluidly connected to each other. The fluid guided along the outer side of the separator plates 2a is preferably hydrogen, such that the through opening 11b is preferably a hydrogen through opening 11b. This is especially due to the fact that the hydrogen through opening 11b has the smallest cross-section compared to the other through openings 11a, 11c.

[0099] In a similar manner, the two through openings 11c or the guide portions (channels) of the stacked body through the system 1 plate formed by the through openings 11c pass through the corresponding convex through portions 13c, through the corresponding distribution structure, and through the back-facing Figure 2 The corresponding flow fields 17b at the outer side of the separator plate 2b of the observer are fluidly connected to each other. The separator plate 2b is the first separator plate 2b in the sense of this disclosure. The fluid guided along the outer side of the separator plate 2b is preferably air or oxygen, such that the through opening 11c is preferably an air or oxygen through opening 11c.

[0100] Conversely, the through opening 11a, or the guide portion (channel) formed by the through opening 11a through the plate stack of system 1, is fluidly connected to each other via cavities 19 clamped or surrounded by separator plates 2a, 2b, which form a cooling fluid distribution structure 17c. This is again achieved, for example, through the through portion 13a. The cavity 19 or the cooling fluid distribution structure 17c is used to guide cooling fluid through the bipolar plates 2, particularly for cooling the electrochemically active regions of the MEA. Thus, the through opening 11a is a cooling fluid through opening, which is particularly evident from its more moderate cross-sectional size compared to the other through openings 11b, 11c.

[0101] Figure 3 A top view of a sub-region of a bipolar plate 20 according to an embodiment of the present invention is shown. The bipolar plate 20 is largely constructed similar to... Figure 2 Examples, but particularly in terms of fluid guidance on its outer and inner sides and in terms of the configuration of the flow field, have the following differences.

[0102] The sub-region shown corresponds to Figure 2 The outer end region along the x-axis 8 includes three through openings 22a, 22b, and 22c. The positioning of these through openings 22a, 22b, and 22c indicates that this view is relative to... Figure 2 It has basically rotated 90°.

[0103] exist Figure 3 The first separator plate 24 of the bipolar plate 20 is observed to be facing outwards towards the observer. The other separator plate 26 of the bipolar plate 20 is... Figure 3 The first separator plate 24 located above is blocked.

[0104] All of the information disclosed here Figures 3 to 13 All of these involve such sub-regions or end regions. However, it should be understood that the corresponding opposing end regions can also be constructed similarly, including three additional through openings 22a, 22b, 22c, and having similar fluid guides. However, there is usually an opposite flow direction there (see [reference to...]). Figure 2 (Explanation).

[0105] Figure 3 The first through opening 22a, apart from its non-restrictive shape, is essentially constructed as similar to Figure 2 The through opening 11c is, by way of example, an air or oxygen through opening. Figure 3 The through opening 22c in the middle, apart from its non-restrictive shape, is basically similar to Figure 2 It is constructed with a through opening 11a, and is a through opening for cooling fluid. Figure 3The through opening 22b, apart from its non-restrictive shape, is essentially similar to... Figure 2 It is constructed with a through opening 11b, and is exemplarily a hydrogen through opening.

[0106] The openings 22a, 22b, and 22c are distributed transversely to the main flow axis S, as described below. For example, their centroids, or their respective faces not shown separately, are offset from each other along the main flow axis S.

[0107] As can be seen, the first through opening 22a is located near the first outer edge 31 of the separator plate 24, which extends along the main flow axis S and thus corresponds to the long side of the separator plate 24. Opposite to this is the second outer edge 33 of the separator plate 24, specifically when viewed along an axis (not shown) extending transversely to the main flow axis S. Therefore, this second outer edge 33 also corresponds to the long side of the separator plate 24.

[0108] Also shown is the third outer edge 35 of the separator plate 24, which extends transversely to the main flow axis S and thus corresponds to the short side (Querseite, transverse side).

[0109] When observed along the main flow axis S, the fourth outer edge, which is positioned opposite to it, is... Figure 3 Not shown in the diagram, this fourth outer edge forms another short edge.

[0110] A distribution region 28 is shown on the outer side of the first separator plate 24, which fluidly connects to the flow field 30, and more specifically, to the main region 32 of the flow field 30, through the opening 22a. The flow field 30 is also formed on the outer side of the first separator plate 24 shown. Both the distribution region 28 and the main region 32 of the flow field 30 have multiple fluid-guiding channels 34, 34.1 and ribs 36, 36.1 positioned between them and separating the channels 34, 34.1. Figure 3 Only the selected structural designations have corresponding reference numerals. In a manner known per se, a corresponding channel 34 of the distribution region 28 is fluidly connected to a plurality of channels 34.1 of the main region 32 of the flow field 30. Specifically, a corresponding channel 34 of the distribution region 28 transitions into (or vice versa) the plurality of channels 34.1 of the main region 32 of the flow field 30, and / or a corresponding channel 34 of the distribution region 28 branches into the plurality of channels 34.1 of the main region 32 of the flow field 30.

[0111] The channels 34.1 of the flow field 30 are elongated and, in the example shown, are straight. They extend parallel to each other and parallel to the main flow axis S of the flow field 30. However, the channels 34 of the distribution region 28 extend at a distinct angle to this main flow axis S.

[0112] The flow field 30 also has a sub-region 38 adjacent to the second outer edge 33, which, according to the preceding embodiment, extends within the electrochemically active region of the bipolar plate 2. This sub-region 38 also has channels, in the form of flow field sub-channels 40. These channels also extend parallel to the main flow axis S of the flow field 30, as illustrated by the direction of extension of the main flow axis S' of the selected flow field sub-channels 40.

[0113] The secondary flow channels 40 are separated from each other by the ribs 42 of the secondary region 38. More precisely, each rib 42 separates two directly adjacent and parallel secondary flow channels 40.

[0114] from Figure 3 It can be seen that the size of the sub-region 38 of the flow field 30 is determined to be significantly smaller than that of the main region 32, and the number of flow field sub-channels 40 included is also significantly less compared to the channels 34.1 of the main region 32. For example, the number of flow field sub-channels 40 can not exceed 10% of the number of channels 34.1 in the main region 32, and in particular, not exceed 5%.

[0115] Additionally or alternatively, the width B1 of the main region 32, measured transversely to the main flow axis S of the main region 32, is at least ten times, and in particular at least twenty times, the corresponding width B2 of the sub-region 38.

[0116] In the example shown, sub-region 38 is not fluidly connected to through opening 22a via distribution region 28. Instead, the fluid connection to through opening 22a is established by means of branch sub-channels 44, marked with dashed lines. These branch sub-channels 44 extend exemplarily along the peripheral section of through opening 22a that does not directly face distribution region 28, particularly away from it, and also exemplarily along corresponding portions of other through openings 22b, 22c. As can be seen from the direction of the dashed lines, the branch sub-channels 44 have a branching form, and in particular, do not extend purely unbranched or in a single strand. However, this can be configured according to other embodiments not shown. The shown orientation is generally not limiting. Branch sub-channels 44 can be supplied by through-sections 13 surrounded by wavy lines, which are similar to... Figure 2 In the direction toward the distribution area 28, fluid may additionally or alternatively be fed through optional through-holes 13.1 and / or 13.2.

[0117] exist Figure 3In this configuration, each through-opening 22a, 22b, 22c has an extension in the y-direction on its side facing the distribution area 28. This extension provides a direct entrance to the distribution area 28 for the multiple through-sections 13, without having to pass through the channel section (guide section) between the two through-openings 22a-22c in the negative x-direction (i.e., towards the flow field 30). Flow is provided only in the positive x-direction, that is, in the direction directly away from the flow field 30, between the two through-openings 22a-22c.

[0118] The arrow tip of the dashed line in branch sub-channel 44 indicates that... Figure 3 In particular, there is a case where fluid is supplied to the flow field 30 from the through opening 22a, rather than being received from the flow field 30. However, it should be understood that the flow direction can also be reversed.

[0119] For example, exiting the through opening 22a can be achieved via through portions 13.1, 13.2, and 13.3. Here, segments 44.1 and 44.2 extend between the through opening 22a and the peripheral protrusion 12d, segment 44.4 extends between the through openings 22c and 22b and the peripheral protrusion (peripheral groove) 12d, while segment 44.2 extends between the through openings 22a and 22c. Through the branch sub-channel 44, fluid passes through the outermost rib 36' of the distribution region 28 and is guided through the exemplary cross-sectionally reduced connecting segment 45 of the branch sub-channel 44 into the sub-region 38 of the flow field 30 arranged adjacent to the second outer edge 33. The outermost rib 36.1' exemplarily forms a structure defining the distribution region 28. It transitions to the outermost rib 36.1' of the main region 32 of the flow field 30. This outermost rib 36.1' exemplarily forms a structure defining the main region 32.

[0120] Figure 3 The diagram also shows an optional second branch sub-channel 49, its orientation marked by dotted lines. This second branch sub-channel 49 also fluidically connects the first through opening 22a to the sub-region 38 of the flow field 30. The branch sub-channel 49 can also be configured as multi-channel and / or branched, but it can also be configured as unbranched and / or single-channel.

[0121] In particular, the second branch sub-channel 49 has a first section 49.1 that extends along the periphery of the cooling fluid through opening 22c toward the distribution area 28. Fluid can be introduced directly into this section from the through opening 22a, for example, through... Figure 2The passage 13 already shown, or the section can be directly introduced into the first section 49.1 via an optional separate passage 13.3 pointing towards it. Furthermore, the second branch sub-channel 49 has a second section 49.2 that extends along the periphery of the hydrogen penetration opening 22b toward the distribution area 28. This second section 49.2 merges into another adjacent section of the connecting section 45 or the first branch sub-channel 44 in the vicinity of the sub-region 30. This second section 49.2 merges into the first section 49.1 at its other end.

[0122] Furthermore, the second branch sub-channel 49 optionally has a segment 49.3 extending between the through openings 22b and c, which merges into the first branch sub-channel 44 and also into the second segment 49.2. This occurs at or near the same end where the second segment 49.2 merges into the first segment 49.1. Even if fluid is supplied to the sub-region 30 through the second branch sub-channel 49, the sub-region 30 is primarily supplied through the first branch sub-channel 44. As a general aspect, and not limited to this embodiment, the first and second branch sub-channels 44, 49 are preferably specifically designed for fluid-conducting connection between the through opening 22a and the sub-region 30. Conversely, the first and second branch sub-channels 44, 49 are not specifically configured for fluid-conducting connection between the through opening 22a and the main region 32, and / or the first and second branch sub-channels 44, 49 are not configured for introducing fluid into the distribution region 28. Accordingly, the first and second branch sub-channels 44, 49 are generally not allocated to the distribution region 28.

[0123] Therefore, both branch sub-channels 44 and 49 have segments, namely segments 44.3 and 49.3, which extend through the two through openings with a vector component in the positive x direction.

[0124] Finally, in sub-region 38, the incoming fluid is separated and guided into four flow field sub-channels 40. The two middle flow field sub-channels 40 are defined by two ribs 42 of sub-region 38, respectively. In the region adjacent to the second outer edge 33, when viewed transversely to the main flow axes S, S', the two outer flow field sub-channels 40 are defined on one side by the ribs 42 of sub-region 38. Further definition on the other side... Figure 3 In the case of the middle left side, this is achieved by the outermost rib 36.1' of the main region 32 of the flow field 30. Figure 3 In the case of the right side, this additional definition is achieved through the adjacent defining element 46.

[0125] The defining element 46 is optionally connected to the outermost sealing flange 48 surrounding the separator plate 24 via a transverse connecting rib 90. The transverse connecting rib 90 prevents fluid from flowing over the flow field 30 on the outer side of the separator plate 24.

[0126] The fluid provides a throttling effect through the exemplary relatively narrow connecting section 45 and through the branching to multiple flow field sub-channels 40. This can be advantageously and specifically configured to adapt the flow rate through the first branch sub-channel 44 and / or the second branch sub-channel 49 to the flow rate of the channel 34 in the distribution region 28.

[0127] Figure 3 This view is particularly schematic because it also shows an exemplary structural orientation in the distribution area 28b on the outer side of another separator plate 26 facing away from the observer. Therefore, this view corresponds to the (sectional) view through the bipolar plate 2 and / or the orthogonal projection of the fluid guides on the respective outer sides of the two separator plates 24, 26 onto a common plane.

[0128] In the distribution region 28b, a channel 34b and a rib 36b are provided to fluidly connect, in this case, the through opening 22b to the flow field 30b (not shown separately) at the outer side of the second separator plate 26. This fluid connection can, in principle, be constructed according to examples of the prior art. Alternatively, it can be similar to the examples disclosed herein, also having at least one branched secondary channel 44, 49 and flow fields subdivided into the main region and secondary regions 32, 38.

[0129] Distribution regions 28, 28b are shown to be positioned at least segmentally opposite each other, or in other words, intersecting, in a manner known per se. This forms a fluidly connected sub-region on the respective inner sides of separator plates 24, 26, allowing cooling fluid to be guided through and / or toward through opening 22c. More precisely, the respective ribs 36, 36b of distribution regions 28, 28b form complementary inner channels in which cooling fluid can be guided. Starting from through opening 22c, cooling fluid flows along the inner channels of the two distribution regions 28, 28b toward flow field 30, more precisely toward the inner side of their main region 32. Here, as previously described, cooling fluid also flows through the region intersecting with the inner channels of distribution regions 28, 28b.

[0130] However, with this configuration of distribution regions 28, 28b, it is not easy to ensure that the cooling fluid can also be guided along the sub-region 38 of the flow field 30 on the inner side. In particular, this is not easily achieved at the through opening 22c and... Figure 3 A fluid connection is established between the cooling fluid sub-channels 41 adjacent to the second outer edge 33, which are not individually visible. The latter are complementaryly formed on the inner side by a corresponding rib 42 of the sub-region 38. Insufficient cooling of the sub-region 38 may cause damage or destruction to the MEA, thereby impairing the performance of the entire electrochemical system.

[0131] exist Figure 3In the diagram, an extended end section of the inner channel of another separator plate 26 illustrates the possibility of providing a cooling fluid connection for the secondary cooling fluid channel 41 of the secondary region 38. This will be explained below according to... Figure 6 Further details will be provided. Based on the following figures, several other possibilities for establishing such cooling fluid connections will also be illustrated. Here, Figures 4 to 12 They respectively show principles similar to Figure 3 The bipolar plate 20 is constructed with sub-regions, which in particular include the fluid inlet region and / or fluid outlet region of the sub-region 38 of the flow field 30, i.e., the end region of the sub-region 38 arranged adjacent to the second outer edge 33. Similarly, the sub-regions shown include the connecting section 45 described above, which is also arranged adjacent to the second outer edge 33.

[0132] exist Figure 4 In the illustrated embodiment, the defining element 46 of the sub-region 38 is again visible, as are the outermost ribs 36' and 36.1' of the main region 32 and the distribution region 28. A first branch sub-channel 44 and a connecting section 45 extending into or potentially out of the sub-region 38 are also shown. The sub-region 38, arranged adjacent to the second outer edge 33, includes four flow field sub-channels 40. Ribs 42 separating these flow field sub-channels 40 are also shown. As previously described, these ribs 42 each form an inner, not individually visible, cooling fluid sub-channel 41. Similar cooling fluid sub-channels 41 will be described in further detail below. Figure 13 It can be seen in the sectional view.

[0133] Figure 4 The rib 42 of the sub-region 38, which is closest to the main region 32, is connected to and / or transitions to the outermost rib 36' of the distribution region 28 via a first protrusion 50. This protrusion 50 protrudes relative to the bottom 43 of the adjacent, unprotruded flow field sub-channel 40, which is closest to the main region 32. This bottom 43 can extend, in particular, in the reference plane of the separator plate 24.

[0134] In other words, specifically when viewed orthogonally to the reference plane of the visible first separator plate 24, the protrusion 50 protrudes relative to the channel bottom 43, which forms at least locally the lowest region on the outer side of the first separator plate 24. Conversely, the protrusion 50 has a smaller height than the rib 42 of the sub-region 38, which is measured orthogonally to the reference plane (see also the discussion below). Figure 11 Rib 42, and especially its outermost rib surface facing the observer, forms at least a locally highest region on the outer side of the first separator plate 24.

[0135] As explained below Figure 9 As can be seen in the perspective view of this embodiment, a rib section 68 with a reduced height relative to the rib 38 is arranged between the protrusion 50 and the rib 38; however, this section 68 has a greater height than the protrusion 50.

[0136] As a general feature of this disclosure, not limited to this embodiment, any protrusions disclosed herein, such as Figure 4 The protrusion 50 can be defined at least on one side, and particularly at least on both sides, by the bottom of the adjacent channel. These two sides can be opposite each other. The remaining two sides, particularly the other two opposite sides of the protrusion having a basic rectangular outline, can be defined by the structure of the corresponding adjacent protrusion, as previously described. Figure 3 This is an illustrative example. Therefore, any protrusion disclosed herein may be spaced apart from the ends of the channel, particularly the ends adjacent to the distribution area, for example, because there may be a segment of the channel extending up to that end. Protrusions may generally be spaced apart from the distribution area, and in particular, do not directly transition into the distribution area. At least one plate region extending near or within the reference plane may separate the protrusion from the distribution area.

[0137] The first protrusion 50 is located at least sectionally in the connecting section 45 of the fluid sub-channel 44. Fluid can flow into (or out of) the adjacent flow field sub-channel 40 via the first protrusion 50. Simultaneously, a recessed region is formed on the inner side by the protrusion 50, defining a cooling fluid (small) path along which the cooling fluid can be guided. Specifically, cooling fluid can be transferred from the recessed inner region formed by the outermost rib 36' of the distribution region 28 to the cooling fluid sub-channel 41, which, on its inner side, passes through the sub-region 38. Figure 4 The uppermost rib 42 is formed therein and complements it. In this way, the protrusion 50 at least partially creates a fluid connection between the cooling fluid secondary channel 41 and the through opening 22c and / or at least one sub-section of such a fluid connection.

[0138] Optionally, additional protrusions 52 and 54 are also constructed. These protrusions are respectively formed as local elevations relative to the adjacent, non-protruding channel bottom 43, but with a reduced height relative to the rib 42. Accordingly, they are allowed to overflow (flood) with fluid on the outer side, but provide recessed sections on the inner side for guiding the cooling fluid.

[0139] The second protrusion 52 is fluid-conductingly connected to the cooling fluid secondary channel 41 on its inner side, the cooling fluid secondary channel 41 being formed by... Figure 4 The upper and middle ribs 42 are formed. A third protrusion 54 is fluid-conductingly connected to a cooling fluid secondary channel 41 on its inner side, which is composed of... Figure 4The ribs 42 are formed in the middle and lower parts. Here, the second and third protrusions 52, 54 extend between and transition into these ribs 42, respectively. Thus, the second and third protrusions 52, 54 are defined by the ribs 42 at least on both sides, particularly on both sides facing each other. Unlike the first protrusion 50, the second and third protrusions 52, 54 are not arranged in a straight line and / or along the longitudinal axis L of the corresponding adjacent rib 42. Instead, they are specifically offset and / or extend laterally thereto.

[0140] With the help of the second and third protrusions 52 and 54, the cooling fluid can be drawn from the inside... Figure 4 The uppermost cooling fluid secondary channel 41 also leads to other cooling fluid secondary channels 41 (or vice versa), these cooling fluid secondary channels 41 are formed by... Figure 4 The middle and lowermost ribs 42 are formed on the inner side.

[0141] It is also shown that the second and third protrusions 52, 54 are arranged along a common straight axis A. This advantageously reduces the length of the flow path of the cooling fluid, particularly until it reaches... Figure 4 The flow path of the cooling fluid secondary channel 41 at the bottom.

[0142] Furthermore, it can be seen that all the protrusions 50, 52, and 54 are located close to the connecting section 45 and therefore also adjacent to the second outer edge 33. This connecting section 45 may be included in, and / or form, such a fluid inlet and / or outlet region 47 of the flow field 30 (depending on the flow direction), particularly its sub-region 38. In other words, the protrusions 50, 52, and 54 are therefore located close to the end of the sub-region 38, which may be present, for example, along the longitudinal axis L of the rib or the main flow axis S or S'. As explained above, this allows for effective cooling over a large length of the sub-region 38. Figure 4 As shown, no protrusions are provided in the gas passages 34.1 of the main region 32. As already explained, the number of flow field sub-passages 40 may not exceed 10% of the number of passages 34.1 in the main region 32, and in particular, not exceed 5%, which also means that protrusions at the bottom of the passages exist in less than 10% of the passages, and especially in less than 5% of the passages.

[0143] For the sake of completeness, it is necessary to mention in Figure 4 The transverse connecting rib 90 between the defining element (limiting element) 46 and the sealing convex edge 48 can be seen again.

[0144] Figure 5 It shows the relationship with Figure 4A similar view, wherein this embodiment is characterized by the varying arrangement and shape of the protrusions 50, 52, and 54. Thus, in this case, the first protrusion 50 is similar to the second and third protrusions 52 and 54 described above, constructed on the sides of the ribs 42 and 36.1' that define it and / or extending transversely to these ribs. One of these ribs is the outermost rib 36.1' of the main region 32 of the flow field 30. The second and third protrusions 52 and 54 are each, in principle, similar to... Figure 4 Example positioning. All the protrusions 50, 52, 54 are again adjacent to the second outer edge 33 and arranged sequentially along a common straight axis A, which extends transversely to, or more precisely orthogonally to, the main flow axis S'.

[0145] As shown in the figure, the protrusions 50, 52, and 54, more specifically, the cooling fluid (small) paths formed by them on their inner sides, may optionally have different flow cross-sections. Therefore, the cooling fluid (small) path formed by the first protrusion 50 on its inner side has the largest flow cross-section compared to the cooling fluid (small) paths on the inner sides of the other protrusions 52 and 54. Here, the maximum, average, and / or minimum flow cross-sections of the corresponding protrusions 50, 52, and 54 can be observed and compared. In the example shown, the flow cross-sections of the corresponding protrusions 50, 52, and 54 are along their orientation... Figure 5 The extension (amount) in the direction of the lowest or outermost rib 42 decreases, and in particular decreases continuously. However, this is not mandatory; for example, a corresponding constant flow cross-section can also exist within each protrusion, see [reference needed]. Figure 10 .like Figure 10 As shown, this can also be achieved by increasing the distance from the outermost rib 36.1' of the main region 32 while maintaining a relatively smaller flow cross-section compared to the previously described protrusions 50, 52, and 54.

[0146] As mentioned above, according to Figure 5 And also according to Figure 10 The reduced flow cross-section allows for at least partial compensation of the decrease in the amount of cooling fluid guided through the corresponding protrusion as the distance from the outermost rib 36.1' increases. This compensation is meaningless or unnecessary in the main region 32, therefore... Figure 5 There are no protrusions in the gas channel 34.1 of the main area 32.

[0147] Figure 6 Another embodiment is shown, in which the structure of another separator plate 26 is shown in dashed lines. In particular, these structures include cooling fluid channels 41' on the inner side of the other separator plate 26, in which cooling fluid can be guided.

[0148] First, referring to the outer side of the first separator plate 24, we can see the protrusions 50 and 52 present there, which have the same characteristics as described above. Figure 5 The protrusions 50, 51, 52, 53, and 54 in the diagram have the same function and provide the same effect.

[0149] The first protrusion 50 is at least segmentally located in the adjacent, Figure 6 The uppermost rib 42 extends in its extending direction, and this rib 42 is located adjacent to the sub-region 38 arranged near the second outer edge 33, which is not visible here. Furthermore, the first protrusion 50 transitions to the outermost rib 36' of the distribution region 28. In this respect, Figure 6 The first protrusion 50 in the middle is at least segmentally related to the positioning and extension. Figure 4 The first protrusion 50 in the middle is basically the same. However, the first protrusion 50 is also... Figure 6 The uppermost rib 42 and the middle rib 42 extend directly and continuously in another section 50'. Here, it provides with Figure 4 and Figure 5 The second protrusion 52 in the middle has essentially the same function. More precisely, this additional section 50' forms an inner cooling fluid (small) path, which allows fluid to be introduced and / or drawn out into the inner cooling fluid sub-channel 41 constructed from the central rib 42.

[0150] Figure 6 The embodiment also includes another protrusion 52, which is similar to Figure 4 and Figure 5 The third protrusion 54 is constructed and positioned to provide the same effect.

[0151] The protrusions 50, 50', and 52, together with the corresponding rib sections of rib 42 located therebetween, allow the cooling fluid to flow in a tortuous manner along its path from the outermost rib 36' to the lowermost rib 42 in the distribution region 28. This creates the main flow axis C of the protrusions, which functionally corresponds to... Figure 4 and Figure 5 Axis A in the middle.

[0152] The raised main flow axis C extends at least segmentally at an angle W relative to the main flow axis S' of the sub-region 38, as schematically shown. For example, this angle W can be less than 60° or less than 45°. In this way, substantially turbulent-free and low-flow-resistance fluid guidance can be achieved between the inner fluid sub-channel 41 and the fluid channel formed on the inner side of the outermost rib 36' of the distribution region 28. Here, the angle W corresponds to the minimum recordable angle (Schnittwinkel) between the raised main flow axis C and the main flow axis S'.

[0153] Referring again to the cooling fluid passage 41' on the inner side of another separator plate 26, at least one such cooling fluid passage 41' extends opposite to the first and second protrusions 50, 52, the cooling fluid passage 41' in Figure 6 Corresponding reference numerals have been assigned to it. In particular, the cooling fluid passage 41' branches such that each of its individual branches is positioned opposite a corresponding inner cooling fluid sub-passage 41. Alternatively, these individual branches can be regarded as inner cooling fluid passages 41' of another separator plate 26, wherein these individual branches are fluidly connected through another, even more inner cooling fluid passage 41' of another separator plate 26, which is at least segmentally opposite to the protrusions 50, 52.

[0154] Figure 6 The diagram shows an inner cooling fluid channel 41', or one end of an inner cooling fluid channel 41', positioned opposite the outermost rib 36' of the first separator plate 24. Since the outermost rib 36' forms an inner channel for guiding cooling fluid, cooling fluid can be transferred (overflowed) into the inner cooling fluid channel 41' of the other separator plate 26. Additionally, cooling fluid can also flow along the protrusions 50, 52 on the inner side. In this way, cooling fluid can be reliably and adequately distributed onto the cooling fluid channels 41 to ensure effective cooling of the sub-region 38 of the flow field 30.

[0155] Figure 7 It shows the relationship with Figure 5 Comparable implementations exist, but the flow cross-sections of the first to third protrusions 50, 51, 52, 53, and 54 are optionally constant and identical. Furthermore, the inner channels, particularly the cooling fluid sub-channels 41' of the other separator plate 26, are again shown by dashed lines. It can be seen that the ribs 42 of the sub-region 38 and the cooling fluid sub-channels 41 formed therefrom are respectively positioned opposite the corresponding inner cooling fluid sub-channels 41' of the other separator plate 26. However, in the illustrated case, these cooling fluid sub-channels 41' do not extend such that they are also positioned opposite the outermost rib 36' of the distribution region 28. The cooling fluid sub-channels 41 of the separator plate 24 and the cooling fluid sub-channels 41' of the other separator plate 26 are both supplied with cooling fluid through this outermost rib 36' or 36.1'. Again, there are no protrusions 50, 52, and 54 at the bottom of the channel 34.1 in the main region 32.

[0156] Figure 8 yes Figure 7A perspective view of a sub-region of the bipolar plate 20 shown. It can be seen that the structure at the outer edge of the separator plate 24 becomes segmentally flattened. This is achieved in the transition region 60, which is specifically flattened to accommodate the reinforced edge region of the MEA (not shown). The transition region 60 extends transversely to the main flow axis S at least along the entire flow field 30, as shown... Figure 3 As shown in the diagram. In the example shown, it can be attributed in principle to the allocation region 28. The transition region 60 includes rib sections and channel sections that transition into the ribs 36.1, 42 and channel 40 of the sub-region 38 and main region 32 of the flow field 30.

[0157] The transition section from the transition region 60 to the actual flow field 30 can be considered as the fluid inlet region and / or fluid outlet region of the flow field 30. Figure 8 The center line is marked with an 80'. Alternatively, Figure 3 The line marked 80 can be considered as the fluid inlet region and / or fluid outlet region of the flow field 30, even if the line 80 belongs to the transition region or distribution region 60, 28 if necessary. At the line 80, the two plates 24, 26 have the minimum rib height on their outer sides at the side closest to the adjacent through opening (in other words: on their side facing the adjacent and / or closest through opening).

[0158] from Figure 8 As can be seen, protrusions 50, 52, and 54 are located within one of the secondary flow channels 41 arranged adjacent to the second outer edge 33, but are very close to the transition region 60. For example, this distance can be less than 5 cm, and particularly less than 1 cm. This distance can be measured along the main flow axis S' of the sub-region 38. This small distance between protrusions 50, 52, and 54 and the transition region 60, in turn, allows for cooling of the sub-region 38 over a considerable length.

[0159] also, Figure 8 As shown, the length L1 of the transition region 60, measured along the main flow axis S' of the sub-region 38, is greater than the comparable measured length L2 of the protrusions 50, 52, and 54. This indicates that the protrusions 50, 52, and 54 form flow barriers of correspondingly short lengths within the flow field sub-channel 41, particularly with narrower cross-sections. However, it is also possible in principle that at least one of the protrusions 50, 52, and 54 may have at least segmentally a length L2 equal to or greater than L1.

[0160] Protrusions 50, 52, and 54 may be arranged only in the transition area 60 (see [reference]). Figure 10 ), or simply arranged in flow field 30 (see Figure 5 , Figure 7 , Figure 8 , Figure 11 , Figure 12Alternatively, it can be arranged both in the transition region 60 and in the flow field 30 (see...). Figure 4 , Figure 6 , Figure 9 ).exist Figure 6 In the middle, the protrusion 50 even extends into the remaining distribution area 28. If the protrusions 50, 52, and 54 are formed in the flow field 30, there is more structural space available in general, which can be distributed between the flow space on the outer side and the flow space on the inner side, that is, between the cooling fluid flow (small) path sandwiched by the protrusions 50, 52, and 54, which is more than the structural space in the transition region.

[0161] Figure 9 A diagram with Figure 8 Similar 3D diagrams, but involving Figure 4 An example of this embodiment. In this case, it can be seen that the protrusions 50, 52, and 54 extend at least segmentally within the transition region 60. Figure 9 The uppermost first protrusion 50 transitions into the rib section 68 described below, which in turn transitions into the rib 42 of the sub-region 38. The first protrusion 50 connects to the outermost rib 36' of the distribution region 28, or more precisely, in such a way that cooling fluid guided at the inner side of the outermost rib 36' can be guided along the inner side of the protrusion 50, and vice versa.

[0162] from Figure 9 As can be seen from the example, the connecting section 45 of the sub-branch channel 44, in the transition region and flowing over (overflowing) the first protrusion 50 (but not the other protrusions 52, 54), branches into multiple channel sections 66 on the outside of the first separator plate 24. These channel sections 66 each transition into one of the flow field sub-channels 41. Furthermore, they are separated from each other by rib sections 68, which transition into the ribs 42 of the sub-region 38 of the flow field 30. The rib sections 68 are lower than the rib surfaces of the ribs 42 of the sub-region 38 because they are located in the transition region 60. In principle, it is also possible that at least a portion of the branch and / or diversion is not located in the transition region 60, but rather in a portion of the distribution region 28 further away from the flow field 30, or at the height of the distribution region 28 in the x-direction (in other words: in the same region along the x-axis and / or the main flow axis S as the distribution region 28). Figure 10 It shows the principle of being consistent with Figure 4 and Figure 5 A comparable partial top view, but in which protrusions 50, 52, and 54 are arranged in the transition area 60. Unlike this, Figure 11 It shows a similar Figure 9 A three-dimensional image. In Figure 10 and Figure 11Each of the drawings shows other embodiments of protrusions 50, 51, 52, 53, and 54. As previously stated, Figure 10 It shows a principle similar to Figure 5 In this case, the flow cross-sections of protrusions 50, 51, 52, 53, and 54 decrease with increasing distance from the main region 32 of the flow field 30. However, compared with... Figure 5 The difference is that, in this case, the flow cross-sections of the corresponding protrusions 50, 51, 52, 53, and 54 are constant. The differences in flow cross-sections among protrusions 50, 51, 52, 53, and 54 are achieved through the dimensional differences of protrusions 50, 51, 52, 53, and 54 measured along the main flow axis S'.

[0163] Figure 11 An alternative scenario is illustrated, in which the corresponding flow cross-sections are achieved using different heights H of protrusions 50, 51, 52, 53, and 54. Height H is measured orthogonal to the reference plane of separator plate 24. Protrusion 50, closest to the main region 32 of the flow field 30, has the largest height H compared to the other protrusions 50 and 52. max .

[0164] Figure 12 Another embodiment is shown, which is essentially similar to Figure 4 It is constructed as follows. However, the channel 40 of the sub-region 38, which is closest to the main region 32 of the flow field 30, not only has a protrusion 50, but also two protrusions 50a and 50b arranged successively in the flow direction of the channel 40. Here, protrusion 50b can be constructed similarly to protrusions 52 and 54, while protrusion 50a is similar to... Figure 4 The protrusion 50 in the middle. In this way, with... Figure 4 In contrast, more cooling fluid can be delivered from the outermost rib 36.1' of the main region 32 to the channel 40 of the sub-region 38.

[0165] Figure 13 A cross-sectional view of the bipolar plate 20 is shown, which in principle can be arranged according to... Figure 11 This is an example construction, but with slightly different dimensional proportions if possible. The cutting plane is perpendicular to the reference plane of separator plates 24 and 26. Figure 11 The axis A extends and / or extends orthogonally to the main flow axis S or S'.

[0166] Figure 13 The image shows the compressed state of the bipolar plate 20 and / or its separator plates 24, 26, firmly, particularly connected to each other by material bonding. Figure 13In the diagram, a first separator plate 24 is shown exemplarily above, and another separator plate 26 is shown below. The inner sides of the separator plates 24 and 26, which are opposite to each other, and their outer sides, which are facing away from each other, can be clearly seen.

[0167] and Figure 4 Comparable, the separator plate 24 has the sealing flange 48 described above and the defining element (limiting element) 46, although the cross-sectional view is based on Figure 11 Not shown separately. The secondary flow channel 40 and rib 42 in the secondary region 38 of the flow field 30 are also marked. The outermost rib 36.1' of the main region 32 of the flow field 30 is also marked. Accordingly, Figure 13 The two channels on the right side are channels 34.1 of the main region 32 on the outer side of the first separator plate 24.

[0168] The cutting plane extends through protrusions 50, 52, and 54. Similar to... Figure 11 The different heights of these protrusions 50, 52, and 54, and the different depths of the corresponding flow field sub-channels 40, are again visible. Additionally, the cooling fluid sub-channels 41 formed inside the ribs 42 of the sub-region 30 are marked.

[0169] from Figure 13 It can be seen that, with the aid of protrusions 50, 52, and 54, the distance D measured perpendicular to the reference plane E between the inner sides of separator plates 24 and 26 increases. This is relative to... Figure 13 The flow field sub-channel 40 of the leftmost first separator plate 24 is particularly suitable, where the separator plate 24 is supported (rested) on another separator plate 26. Through their increased distance D, protrusions 50, 52, and 54 define the inner (small) cooling fluid paths to guide or drain the cooling fluid into or from each cooling fluid sub-channel 41 as described above. Again, there are no protrusions 50, 52, and 54 at the channel bottom 34.1 in the main region 32. Similarly, in the sub-region 38, the channel bottom 43 closest to the sealing protrusion 48 is implemented without channel protrusions because no coolant guidance is performed there. Instead, the channels located therein are equipped with protrusions 50, 52, and 54 for guiding coolant, and the bottom of the protruding channels is correspondingly irregularly marked with 43'.

[0170] If already Figure 3 As explained in the context, Figure 13The width B1 of the main region 32, shown only in sections, measured transversely to its main flow axis S, can be at least ten times, and particularly at least twenty times, the corresponding width B2 of the sub-region 38. This means that the protrusions 50, 52, 54… of the channel bottom 43' are provided only in regions spanning less than 10%, and particularly less than 5%, of the total width of the flow field 30, i.e., not across the entire width of the flow field 30. This region, i.e., the sub-region 38, is preferably located adjacent to the second side edge 33, while conversely, the protrusions 50, 52, 54 are absent adjacent to the opposite first side edge 31, which also stems from… Figure 3 This conclusion is drawn from a combined observation with one of the subsequent accompanying figures.

[0171] By way of example only, the separator plate 26 has a sub-region 38 on its outer side that is substantially comparable in construction, specifically including protrusions 50, 52, 54 that are similarly arranged and sized. However, this is not mandatory.

Claims

1. A separator plate (24, 26) for an electrochemical system, characterized in that, include: - At least one first through opening (22a) for allowing a first reactive fluid to flow through the separator plates (24, 26); at least one second through opening (22b) for allowing a second reactive fluid to flow through the separator plates (24, 26); and at least one third through opening (22c) for allowing cooling fluid to flow through the separator plates (24, 26). - On the outside of the separator plates (24, 26): at least one distribution area (28), flow field (30) and at least one branch sub-channel (44); The distribution area (28) fluidly connects the first through opening (22a) to the main region (32) of the flow field (30); Among them, the branch sub-channel (44): - Connect the first through opening (22a) to the sub-region (38) of the flow field (30) in a fluid-conducting manner; and -The branch sub-channel (44) extends at least segmentally along the peripheral segment of the first and / or second and / or third through opening (22a, 22a, 22c) away from the distribution area (28); The sub-region (38) has multiple flow field sub-channels (40) and ribs (42) formed between every two flow field sub-channels (40). The ribs (42) respectively form complementary cooling fluid secondary channels (41) on the inner side of the separator plates (24, 26). The branch sub-channel (44) and / or the flow field sub-channel (40) have at least one segmental protrusion (50, 52, 54) at the bottom (43') of the channel; and The at least one protrusion (50, 52, 54) forms a fluid connection section between the at least one cooling fluid secondary channel (41) and the third through opening (22c) on the inner side of the separator plate (24, 26).

2. The separator plates (24, 26) according to claim 1, Its features are, The at least one protrusion (50, 52, 54) is formed in one of the flow field sub-channels (40), and the distance from the protrusion (50, 52, 54) to the nearest fluid inlet region and / or fluid outlet region of the flow field (30) along the main flow axis (S') of the flow field sub-channel (40) is at most 5 cm, particularly at most 2 cm, more particularly at most 1 cm, and / or at most 10% of the total length of the flow field sub-channel (40), particularly at most 6%.

3. The separator plate (24, 26) according to claim 1 or 2, characterized in that, A second branch sub-channel (49) is formed, the second branch sub-channel: - Connect the first through opening (22a) to the sub-region (38) of the flow field (30) in a fluid-conducting manner; and - At least segmentally extending along the periphery of the second and / or third through opening (22c) toward the distribution area (28).

4. The separator plates (24, 26) according to claim 3, Its features are, The length of the at least one protrusion (50, 52, 54) in the extension direction of the flow field sub-channel (40) is at most 5% of the length from the shortest branch sub-channel (44, 49) to the boundary of the flow field (30) or the flow field sub-channel (40). and / or The at least one protrusion (50, 52, 54) extends along the main flow axis (S') of the flow field sub-channel (40) in the extension direction of the flow field sub-channel (40) with a length of up to 2 cm, particularly up to 1 cm or up to 0.5 cm.

5. The separator plate (24, 26) according to any one of the preceding claims, Its features are, The average height (H) of the at least one protrusion (50, 52, 54) measured perpendicular to the reference plane (E) has the maximum height (H) of the structure measured perpendicular to the reference plane (E). max The structure defines the branch sub-channel (44) or the flow field sub-channel (40) in which the at least one protrusion (50, 52, 54) is formed, with a maximum of 80%, a maximum of 60%, and particularly a maximum of 50%.

6. The separator plate (24, 26) according to any one of the preceding claims, Its features are, The at least one protrusion (50, 52, 54) is formed in one of the flow field sub-channels (40) and connects the two ribs (42) that define the flow field sub-channel (40) to each other.

7. The separator plate (24, 26) according to any one of the preceding claims, Its features are, The protrusions (50, 52, 54) are formed in one of the flow field sub-channels (40) and connect the rib (42) that defines the flow field sub-channel (40) and the structure (36.1') that defines the main region (32) of the flow field, and can guide cooling fluid at the inside of the structure.

8. The separator plate (24, 26) according to any one of the preceding claims, Its features are, The sub-region includes at least three ribs and at least two flow field sub-channels (40), each flow field sub-channel being defined at least segmentally by two adjacent corresponding ribs, wherein the adjacent corresponding ribs are connected to each other by at least one segmental protrusion (50, 52, 54) at the bottom of the flow field sub-channel (40) defined by them.

9. The separator plates (24, 26) according to claim 8, Its features are, The corresponding at least one protrusion (50, 52, 54) is distributed along a common axis within the flow field sub-channel (40), the common axis extending orthogonally to the main flow axis (S') of the flow field sub-channel (40).

10. The separator plates (24, 26) according to claim 8, Its features are, At least one of the protrusions (50, 52, 54) within the flow field sub-channel (40) has a protruding main flow axis (C), which extends at an angle (W) of less than 60° or less than 45° to the main flow axis (S') of the flow field sub-channel (40).

11. The separator plate (24, 26) according to claim 9 or 10, Its features are, The inner flow cross-section of the protrusions (50, 52, 54) that are farther away from the main region (32) is smaller than the inner flow cross-section of the corresponding other protrusion (50, 52, 54).

12. The separator plate (24, 26) according to any one of the preceding claims, Its features are, The separator plates (24, 26) include a continuously descending transition region (60), which includes end sections transitioning to the branch sub-channel (44) and the distribution region (28) in the flow field (30). In the flow field (30), the average channel height measured perpendicular to the reference plane (E) is h1, while in the transition region (60), the highest channel height measured perpendicular to the reference plane (E) is h1. max , where h max ≤0.95·h1.

13. The separator plates (24, 26) according to claim 12, Its features are, The at least one protrusion (50, 52, 54) is formed in a section of the branch sub-channel (44), the section extending in the transition region (60).

14. The separator plates (24, 26) according to claim 13, Its features are, The branch sub-channel (40) branches into multiple channel segments (66) within the transition region (60), each channel segment being separated by a rib segment (68). The channel segment (66) transitions into the flow field sub-channel (40), and the rib segment (68) transitions into the rib (42) of the sub-region (38). The at least one protrusion (50, 52, 54) is formed at least in one of the channel segments (66) and is connected to a structure (36') that defines the distribution area (28) and can guide cooling fluid at the inside of the structure.

15. The separator plate (24, 26) according to any one of claims 12 to 14, Its features are, The length (L2) of the at least one protrusion (50, 52, 54) along the main flow axis (S') of the secondary flow channel (40) is less than the length (L1) of the transition region (60) along the main flow axis (S').

16. The separator plate (24, 26) according to any one of the preceding claims, Its features are, The separator plate (24, 26) has at least two segmental protrusions (50, 50') arranged successively on the bottom of the channel (43') in at least one continuous flow channel having a branch sub-channel (44) and the flow field sub-channel (40) connected thereto.

17. The separator plate (24, 26) according to any one of the preceding claims, Its features are, When viewed in a cross-sectional plane perpendicular to the reference plane (E) of the separator plates (24, 26), the protrusions (50, 52, 54) protrude relative to the reference plane (E) higher than the bottom (43) of the channels in the main region (32) of the distribution area (28) and / or the flow field (30), and in particular higher than all of the bottoms (43) of the channels therein.

18. The separator plate (24, 26) according to any one of the preceding claims, Its features are: The protrusions (50, 52, 54) achieve a unique fluid connection between the third through opening (22c) and the at least one cooling fluid secondary channel (41); and / or The protrusions (50, 52, 54) are defined on both sides by the bottom (43) of the adjacent channel.

19. The separator plate (24, 26) according to any one of the preceding claims, Its features are, The distribution area (28) and / or the main area (32) of the flow field (30) have no protrusions (50, 52, 54) at the bottom of the channel (43).

20. A bipolar plate (20) for use in an electrochemical system, Including a first separator plate (24) according to any one of claims 1 to 19 and including a second separator plate (26), characterized in that, The inner sides of the first and second separator plates (24, 26) are opposite each other, allowing the cooling fluid to be guided between them.

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