Plate-shaped structure for a fuel cell, stack of plate-shaped structures and method

Abstract

A plate-shaped structure, for example a bipolar plate, for a fuel cell has: a flow field; inlet openings and outlet openings for an anode gas and / or a cathode gas and / or a coolant; and a plurality of recesses in at least one first main surface of the plate-shaped structure, said recesses being designed - to counteract a slipping of the plate-shaped structure relative to another plate-shaped structure when the plate-shaped structure and the other plate-shaped structure are stacked on top of one another and / or - to receive a filling material in order to counteract a slipping of the plate-shaped structure relative to another plate-shaped structure and / or in order to keep the plate-shaped structure and the other plate-shaped structure spaced apart when the plate-shaped structure and the other plate-shaped structure are stacked on top of one another.

Description

[0001] PLATE-SHAPED STRUCTURE FOR A FUEL CELL, STACK OF PLATE-SHAPED STRUCTURES AND METHOD

[0002] The present invention relates to a plate-shaped structure for a fuel cell, a stack of plate-shaped structures, and a method for handling at least two plate-shaped structures for a fuel cell.

[0003] The invention is particularly applicable in connection with bipolar plates and bipolar plate stacks and is therefore primarily explained with reference to a bipolar plate and a bipolar plate stack. However, the invention is also applicable in connection with other plate-shaped structures for a fuel cell and a stack of such other plate-shaped structures, and is thus not limited to bipolar plates. Examples of such other plate-shaped structures include, among others, an anode intermediate plate, a cathode intermediate plate, an anode end plate, and a cathode end plate.

[0004] Fuel cell systems with a fuel cell stack comprising several stacked bipolar plates are generally known in the prior art. A bipolar plate is disclosed, for example, in WO 2022 / 223657 A2.

[0005] In the production of a fuel cell stack, the bipolar plates are manufactured, usually by a dedicated bipolar plate manufacturer, and then sent to a fuel cell stack assembler, also known as a stacker, for further processing. This involves stacking the plates loosely on top of each other and shipping them as a (loose) stack. There is a risk that the individual bipolar plates may shift relative to one another, for example, due to vibrations during transport, and their surfaces may be damaged. Such damage can occur even with very slight shifts. Sometimes, the bipolar plates can be damaged simply by being stored in a loose stack, for example, by impacts or vibrations.

[0006] It is one of the tasks of the present revelation to at least mitigate the problems discussed above.

[0007] The solution to this problem is achieved according to the teaching of the independent claims. Various embodiments and further developments of the solution are the subject of the dependent claims.

[0008] A first aspect of the present disclosure relates to a plate-shaped structure for a fuel cell, wherein the plate-shaped structure has: a flow field;

[0009] Inlet and outlet openings for an anode gas and / or a cathode gas and / or a coolant; and a plurality of recesses in at least one first principal surface of the plate-shaped structure, which are designed to

[0010] - to counteract slippage of the plate-shaped structure relative to another plate-shaped structure when the plate-shaped structure and the other plate-shaped structure are stacked on top of each other, and / or

[0011] - to incorporate a filling material to prevent the plate-shaped structure from slipping relative to another plate-shaped structure and / or to keep the plate-shaped structure and the other plate-shaped structure apart when the plate-shaped structure and the other plate-shaped structure are stacked on top of each other.

[0012] The operating principle and general structure of a plate-shaped device for a fuel cell, such as a bipolar plate with a flow field and inlet and outlet openings for an anode gas and / or a cathode gas and / or a coolant, is generally known and is therefore not described in detail. Only some features of a typical plate-shaped device for a fuel cell—again using a typical bipolar plate as an example—are highlighted below. One, several, or all of these features may also be applied to the present invention, but this should not necessarily be considered a limitation.

[0013] The shape of a typical bipolar plate is essentially that of a very thin cuboid with two essentially rectangular, opposing main faces. The extent of these faces in the two dimensions in which the rectangle extends is significantly greater than the thickness (in the third dimension, i.e., orthogonal to the main faces) of the bipolar plate. Here, the term "main face" is not to be understood in the mathematical sense of a flat surface extending only in two dimensions, but rather in the sense of a side of a body that can exhibit a three-dimensional structure. However, the extent of such a side in two spatial dimensions is (significantly) greater than the extent of this structure in the third spatial dimension.

[0014] In a typical rectangular bipolar plate, the adjacent inlet openings are located near an edge at one end of the plate, and the corresponding adjacent outlet openings are located near an edge at the other end, opposite the first. In the case of non-square main surfaces of a typical bipolar plate, i.e., with main surfaces that are larger in one dimension (referred to here as the longitudinal direction) than in another (referred to here as the transverse direction), the first and second ends, with their respective inlet and outlet openings, are longitudinally opposite each other and thus as far apart as possible. The flow field typically lies longitudinally between the inlet and outlet openings.

[0015] Other plate-shaped structures for a fuel cell can be similarly designed.

[0016] The majority of recesses that the plate-shaped structure has according to the first aspect do not include, in particular, the inlet and outlet openings for an anode gas and / or a cathode gas and / or a coolant, nor openings or channels found in the flow field. The majority of recesses are therefore recesses that the plate-shaped structure has according to the first aspect in addition to the inlet and outlet openings for an anode gas and / or a cathode gas and / or a coolant, or openings or channels of the flow field of the plate-shaped structure.

[0017] The recesses can be designed, for example, as through-holes, meaning recesses that extend through the entire thickness of the plate-shaped structure. Alternatively, the recesses can be designed as blind holes, meaning they do not extend through the entire thickness of the plate-shaped structure. In any case, the recesses are accessible from the first main surface and thus form a localized depression within that surface. In particular, a channel or other cavity that extends solely within the interior of the plate-shaped structure without reaching the surface (here: the first main surface) is not to be considered a recess according to the first definition.

[0018] Viewed in the longitudinal and transverse directions of the plate-shaped structure, the recesses can have a smaller cross-section, in particular a significantly smaller cross-section, than the entrance and exit openings. For example, the recesses can have a cross-section of a few square millimeters down to a few square centimeters, for example, less than 10 cm². 2 , 5 cm 2 , 3 cm 2 , 2 cm 2 , 1 cm 2 , 0.5 cm 2 or 0.3 cm 2 .

[0019] As mentioned above, there is a risk of slippage when another plate-shaped structure is placed on top of the first, i.e., when the first and second plate-shaped structures are stacked on top of each other. In this context, slippage of the first plate-shaped structure relative to another plate-shaped structure is understood to mean a relative movement between the first and second plate-shaped structure that has at least one component of movement in the longitudinal and / or transverse direction, or that occurs predominantly or exclusively in a plane spanned by the longitudinal and transverse directions. This also includes rotation or a combination of rotation and translation of the first plate-shaped structure relative to the second plate-shaped structure.Such a slippage includes the cases where 1) the plate-shaped structure moves relative to its surroundings, while the other plate-shaped structure remains stationary relative to its surroundings, 2) the other plate-shaped structure moves relative to its surroundings, while the plate-shaped structure remains stationary relative to its surroundings, and 3) both the plate-shaped structure and the other plate-shaped structure move relative to their surroundings.

[0020] The recesses can counteract slippage of the plate-shaped structure relative to the other plate-shaped structure, even without the inclusion of filler material, as described below. Compared to a plate-shaped structure that does not have the recesses described above but is otherwise identical in construction to the plate-shaped structure of the first aspect, such counteraction can mean that, under otherwise identical conditions (for example, regarding shocks or vibrations), slippage of the plate-shaped structure of the first aspect relative to the other plate-shaped structure is prevented.

[0021] - is less likely - occurs less frequently

[0022] - only occurs with stronger impacts or vibrations

[0023] - is less pronounced (i.e., the path of displacement is shorter) than is the case with the plate-shaped structure used for comparison. In some cases, displacement of the plate-shaped structure of the first aspect relative to the other plate-shaped structure can even be completely avoided.

[0024] The recesses create a small gap between adjacent plate-shaped structures, increasing the frictional force between them. When a force perpendicular to the stacking direction acts on one of the plate-shaped structures, a force that would normally cause the plate-shaped structures to slide against each other, the recess acts as a mechanical barrier, making it difficult for one plate-shaped structure to slide over the other. This increased friction helps prevent the plate-shaped structures from sliding against each other.

[0025] When a filler material is incorporated into the recesses, slippage can be prevented even more effectively than if the recesses were simply filled with ambient air. This improved effect can be achieved, in particular, through contact between the filler material and the other plate-shaped structure. This can be due, in particular, to a frictional or positive locking mechanism between the filler material and the other plate-shaped structure. The filler material can completely or partially fill the recesses (or at least one or some of them). Furthermore, the filler material can maintain a distance between the plate-shaped structure and the other plate-shaped structure. Finally, the filler material can be made of a material or have a surface with a different roughness than the plate-shaped structure.

[0026] The following describes various exemplary embodiments of the plate-shaped structure, which, unless expressly excluded or technically impossible, can be combined arbitrarily with each other and with the second and / or third aspect of the present disclosure described below.

[0027] The inlet and outlet openings can be arranged at opposite ends of the plate-shaped structure. In particular, all inlet openings are arranged at a first end of the plate-shaped structure, and all outlet openings at a second end. As previously described, these ends can be opposite each other along the longitudinal direction of the plate-shaped structure. As is also common in the prior art, the inlet and outlet openings are located at a certain distance from their respective ends. The area created by this distance between the inlet or outlet openings and the corresponding, generally nearest, edge of the plate-shaped structure is also referred to here as the edge region of the plate-shaped structure.Alternatively, the term "boundary area" used here can also be understood to define an area (on the first main surface of the plate-shaped structure) that lies outside a smallest convex area in which the flow field and all inlet and outlet openings are located.

[0028] In the present case, the direction between the entrance and exit openings is also referred to as the longitudinal direction even if this does not necessarily describe the greatest extent of the plate-shaped structure, i.e., if the entrance and exit openings are not located opposite each other at the furthest ends of the plate-shaped structure.

[0029] At least two of the multiple recesses can be arranged in a first edge region of the plate-shaped structure, and / or at least two of the multiple recesses can be arranged in a second edge region of the plate-shaped structure, opposite the first edge region. This effectively counteracts slippage, especially if the recesses in the first edge region are relatively far apart and the recesses in the second edge region are also relatively far apart, for example, each near a corner (in the case of a rectangular plate-shaped structure, and correspondingly at similar positions in the case of a non-rectangular plate-shaped structure).

[0030] At least one of the multiple recesses can be arranged between adjacent inlet openings and / or at least one of the multiple recesses can be arranged between adjacent outlet openings. This allows any available space between adjacent inlet openings or outlet openings to be used effectively to counteract slippage. Alternatively or additionally, at least one of the multiple recesses can be arranged between the flow field and one or more inlet openings and / or at least one of the multiple recesses can be arranged between the flow field and one or more outlet openings. This also allows any available space to be used effectively. In particular, the fact that inlet or outlet openings can be arranged between the flow field and one or more outlet openings can be exploited.Outlet openings for plate-shaped structures used in fuel cells often have a round cross-section or a cross-section with rounded corners. These rounded shapes can create a surface area that lies between two inlet or outlet openings and the flow field.

[0031] The majority of the recesses can be arranged in those areas of the first main surface of the plate-shaped structure that, viewed in the stacking direction, are furthest away from a central plane of the plate-shaped structure. This can help ensure that the plate-shaped structure and another plate-shaped structure lie against each other (at least) in areas where recesses are located, thus preventing them from slipping relative to each other.

[0032] At least one of the multiple recesses can have a shape that essentially corresponds to the shape of a concave hemisphere or spherical cap and / or has a cross-section that defines a polygon or a hexagon. The shape of the recesses can be particularly relevant if a filling material is included in the recesses or if it is intended that a filling material will be included in the recesses. However, various other shapes and cross-sections are also conceivable.

[0033] As previously mentioned, a filling material can be accommodated by at least one of the multiple recesses. The filling material can protrude from the first main surface of the plate-shaped structure. Particularly in the latter case, this can effectively prevent the plate-shaped structure from slipping relative to another plate-shaped structure. However, even if the filling material is flush with the corresponding recess, this can also prevent slippage.

[0034] If a filler material is accommodated by at least one of the multiple recesses, it can, for example, consist of adhesive, polyurethane, rubber, and / or ethylene propylene diene monomer (EPDM) rubber. These materials are examples of fillers that can be particularly effective in preventing slippage—especially compared to an otherwise identical plate-shaped structure without a filler material.

[0035] In general, if a filling material is received through at least one of the multiple recesses, the filling material can be of a material that, in a stacked arrangement of the plate-shaped structure and the subsequent plate-shaped structure, can counteract slippage of the plate-shaped structure relative to the subsequent plate-shaped structure to a greater extent than would be the case in a stacked arrangement of the plate-shaped structure and the subsequent plate-shaped structure without filling material. In particular, materials with a high coefficient of friction are suitable as filling material (possibly for combination with the material of a typical plate-shaped structure for a fuel cell). The filling material should be such that it does not (significantly) damage the surface of the plate-shaped structure or the subsequent plate-shaped structure.

[0036] The filling material can, for example, be elastically deformable. The filling material can, for example, have a modulus of elasticity of less than 10 GPa, 8 GPa, 6 GPa, 4 GPa, 2 GPa, 1 GPa, or 0.5 GPa.

[0037] If a filling material is received through at least one of the plurality of recesses, the filling material may have a shape adapted to the shape of the at least one recess, and / or wherein the filling material is substantially in the shape of a hemisphere, a sphere or an ovoid, and / or wherein a maximum cross-section of the filling material is larger than a cross-section of the at least one recess.

[0038] A shape of the filler material adapted to the shape of the corresponding recess can help ensure that the filler material is (at least partially) securely contained within the recess and, if necessary, remains in the recess even under shocks or vibrations (at least up to a certain intensity). Suitable shapes for this purpose include, among others, the aforementioned hemisphere, sphere, or ovoid. An ovoid—provided its longitudinal axis is oriented essentially parallel to the stacking direction—can, when stacked with one or more other flat-shaped structures, deform itself into a sphere under the weight of the stacked structures.

[0039] The filling material can also have other shapes, including shapes with a hexagonal cross-section or other polygonal cross-sections.

[0040] If, as mentioned above, the maximum cross-section of the filling material is larger than the cross-section of the at least one recess, it can be ensured that at least part of the filling material protrudes beyond the recess, which in turn can help to keep the plate-shaped structure and the other plate-shaped structure at a safe distance.

[0041] Additionally or alternatively, the extent of the filling material in the stacking direction can be greater than the extent of the corresponding recess in the stacking direction.

[0042] The plate-shaped structure can have a plurality of recesses in a second main surface of the plate-shaped structure. Optionally, the plurality of recesses in the second main surface of the plate-shaped structure can be arranged at positions that correspond to positions in the first main surface of the plate-shaped structure where the plurality of recesses in the first main surface of the plate-shaped structure are arranged. In other words, the positions of the recesses in the first and second main surfaces can be identical or at least substantially identical, except for their position in the stacking direction.

[0043] Providing recesses in both main surfaces of the plate-shaped structure can help to prevent the plate-shaped structure from slipping not only relative to another plate-shaped structure arranged above it, but also relative to another plate-shaped structure arranged below it.

[0044] A particularly secure arrangement against slippage can be achieved by stacking two or more plate-shaped structures with recesses at corresponding positions on the first and second main surfaces. In such an arrangement, filling material, especially a filler such as a rubber ball, can be partially positioned in a recess of one plate-shaped structure and partially in a recess of another (e.g., one stacked above it). The filling material can thus keep the plate-shaped structures at a distance and also counteract slippage perpendicular to the stacking direction.

[0045] The plate-shaped structure can have a surface roughness in a locally limited area around at least one of the plurality of recesses, in particular around several of the plurality of recesses in locally limited areas, in particular around all of the plurality of recesses in locally limited areas, which is greater than a surface roughness of the plate-shaped structure outside the area or areas.

[0046] Additionally or alternatively, it is possible that the recess – for example, due to manufacturing processes – does not form a sharp edge with the surrounding surface of the plate-shaped structure, but that the transition from the surface of the plate-shaped structure to the recess is rounded in a locally limited surrounding area.

[0047] Such an ambient area (with roughness and / or rounding) can have a width of, for example, a few millimeters (e.g., 1, 2, or 3 millimeters) or less than 1 millimeter, for example, less than 0.5 mm.

[0048] The surface geometry of the plate-shaped structure is altered in the area of ​​the recesses, or around each individual recess, by a previously described rounding, curvature, or roughness. This can be caused, for example, by embossing (to form the recesses), coating, or similar processes. The curvature or roughness can counteract slippage of the plate-shaped structures relative to one another—even if there is no filler material in the recess(s).

[0049] A second aspect of the present disclosure relates to a stack of plate-shaped structures, comprising one of the plate-shaped structures described above and at least one further plate-shaped structure. The plate-shaped structure and the at least one further plate-shaped structure may be arranged substantially parallel to each other and / or stacked on top of each other.

[0050] A third aspect of the present disclosure relates to a method for handling at least two plate-shaped structures, wherein the method comprises:

[0051] Providing one of the previously described plate-shaped structures; and placing another plate-shaped structure on top of the plate-shaped structure.

[0052] This method can be used, for example, when several plate-shaped objects need to be transported, especially over longer distances, such as from a manufacturer to a forklift.

[0053] The method can further involve inserting filler material, at least partially, into one or more of the recesses. This can prevent the plate-shaped structure and subsequent plate-shaped structures from slipping. If necessary, this can also keep the plate-shaped structures spaced apart. This could, for example, take place before the plate-shaped structures are transported, such as at a manufacturer's facility.

[0054] The process can further include removing the additional plate-shaped structure from the plate-shaped structure and removing the filling material from the plate-shaped structure. This could, for example, take place after the transport of the plate-shaped structure and the additional plate-shaped structure, such as by a forklift.

[0055] The features and advantages described in relation to the first aspect of the revelation and its advantageous design also apply, at least where technically appropriate, to the second and third aspects of the revelation and their advantageous design, and vice versa.

[0056] Any terms used herein, such as "comprises," "includes," "features," "has," "with," or any other variant thereof, are intended to cover non-exclusive inclusion. For example, a method or apparatus that includes or features a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent in such method or apparatus.

[0057] Furthermore, unless explicitly stated otherwise, "or" refers to an inclusive "or" and not an exclusive "or". For example, a condition A or B is satisfied by each of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present). The terms "a" or "an" as used here are defined as "one or more". The terms "another" and "another", as well as any other variant thereof, are to be understood as "at least one other".

[0058] The term "plural", as used here, is to be understood in the sense of "two or more".

[0059] The terms "configured" or "set up" to perform a specific function (and their respective variations) are used here to mean that the device in question is already in a configuration or setting in which it can perform the function, or at least that it is adjustable—i.e., configurable—so that it can perform the function after appropriate adjustment. Configuration can be achieved, for example, by adjusting parameters of a process sequence or by using switches or similar devices to activate or deactivate functionalities or settings. In particular, the device can have several predefined configurations or operating modes, allowing configuration to be performed by selecting one of these configurations or operating modes.

[0060] Further features, advantages and applications of the revelation will be revealed in the following description in connection with the figures, in which the same reference signs are consistently used for the same or corresponding elements of the revelation.

[0061] For the sake of clarity, the figures are at least partially schematic or highly simplified. Furthermore, embodiments are again explained using the example of a bipolar plate for the sake of a compact presentation, although it is reiterated that corresponding features can also be applied to other plate-shaped structures for fuel cells.

[0062] They show:

[0063] Fig. 1 shows a bipolar plate in top view according to one embodiment of the present disclosure,

[0064] Fig. 2 is a cross-sectional view of a section of a bipolar plate according to one embodiment of the present disclosure, Fig. 3 is a cross-sectional view of a section of a bipolar plate according to another embodiment of the present disclosure,

[0065] Fig. 4 shows a cross-sectional view of a section of a bipolar plate according to a further embodiment of the present disclosure,

[0066] Fig. 5 shows a cross-sectional view of sections of a bipolar plate and another bipolar plate according to a further embodiment of the present disclosure,

[0067] Fig. 6 shows a cross-sectional view of sections of a bipolar plate and another bipolar plate according to a further embodiment of the present disclosure,

[0068] Fig. 7 shows a cross-sectional view of sections of a bipolar plate and another bipolar plate according to a further embodiment of the present disclosure,

[0069] Fig. 8 shows a cross-sectional view of a recess and adjacent areas of a

[0070] Bipolar plate according to a further embodiment of the present disclosure,

[0071] Fig. 9 shows a cross-sectional view of a recess and adjacent areas of a

[0072] Bipolar plate according to a further embodiment of the present disclosure,

[0073] Fig. 10 shows a cross-sectional view of a recess and adjacent areas of a

[0074] Bipolar plate according to a further embodiment of the present disclosure,

[0075] Fig. 11 shows a cross-sectional view of a recess and adjacent areas of a

[0076] Bipolar plate according to a further embodiment of the present disclosure,

[0077] Fig. 12 shows a cross-sectional view of a recess and adjacent areas of a bipolar plate according to a further embodiment of the present disclosure,

[0078] Fig. 13 shows a top view of a recess according to a further embodiment of the present disclosure,

[0079] Fig. 14 shows a top view of a recess according to a further embodiment of the present disclosure,

[0080] Fig. 15 is a flowchart illustrating a process according to one embodiment of the present disclosure, and

[0081] Fig. 16 shows a cross-sectional view of a recess and adjacent areas of a bipolar plate according to two further embodiments of the present disclosure.

[0082] Fig. 1 shows a top view of a bipolar plate 1 according to one embodiment of the present disclosure. In the example shown, the bipolar plate 1 has an approximately cuboid shape, with only the upper side, or the first main surface 2, being shown in Fig. 1. Fig. 1 also indicates a coordinate system in the lower region to illustrate the transverse direction X, the longitudinal direction Y, and the stacking direction Z. The bipolar plate 1 has a larger extent in the longitudinal direction Y than in the transverse direction X, which in turn is (significantly) larger than the extent of the bipolar plate in the stacking direction Z. The extent of the bipolar plate 1 in the stacking direction Z is not shown in Fig. 1 but is indicated in Fig. 2.

[0083] A relatively large, central area of ​​the first main surface 2 is occupied by a flow field 4. Adjoining the flow field 4 in the longitudinal direction Y are inlet openings 5 ​​(or 5a, 5b, and 5c) and outlet openings 6 (or 6a, 6b, and 6c) for an anode gas and / or a cathode gas and / or a coolant. In the example shown, the inlet openings 5 ​​are arranged side by side in the transverse direction X, as are the outlet openings 6. As already mentioned, the operation and general structure of a bipolar plate 1 with a flow field 4 and inlet openings 5 ​​and outlet openings 6 for an anode gas and / or a cathode gas and / or a coolant are not described in detail.

[0084] Along the longitudinal direction Y of the bipolar plate 1, edge regions 8 adjoin the inlet openings 5 ​​and the outlet openings 6. One of the edge regions 8 lies between the inlet openings 5 ​​and the edge of the bipolar plate 1 closest in the longitudinal direction Y (in Fig. 1, the top edge of the bipolar plate 1). The other edge region 8 lies between the outlet openings 6 and the edge of the bipolar plate 1 closest in the longitudinal direction Y (in Fig. 1, the bottom edge of the bipolar plate 1). Alternatively or additionally, the outer areas lying in the transverse direction X can also be considered edge regions 8, i.e., the areas that lie in the transverse direction X between the entire assembly consisting of the flow field 4, inlet openings 5, and outlet openings 6 and the left or right edge of the bipolar plate 1 in Fig. 1.In other words, boundary region 8 can also be considered a region of the first principal surface 2 of the bipolar plate 1 that lies outside the smallest convex region encompassing the flow field 4, the inlet openings 5 ​​and the outlet openings 6.

[0085] In the boundary regions 8, there are multiple recesses 7, indicated by small circles in Fig. 1. It should be noted that the shape, size, number, and arrangement of the recesses 7 are not limited to the embodiment shown in Fig. 1. It should also be noted that the small circles indicated in the flow field 4, as well as the inlet openings 5 ​​and outlet openings 6, are not to be considered recesses 7 within the meaning of this disclosure. Examples of the shapes of the recesses 7 are described in connection with the other figures.

[0086] While Fig. 1 shows the recesses 7 predominantly in those edge regions 8 that are arranged near the two longitudinal Y-directed edges of the first main surface 2, individual recesses 7 or a plurality of recesses 7 can also be arranged in the transverse X-directed edge regions of the first main surface 2 (i.e., in Fig. 1 to the left and / or right of the flow field 4, the inlet openings 5 ​​and / or the outlet openings 6), possibly in greater numbers than in the edge regions 8 at the longitudinal Y-directed ends of the first main surface 2. In Fig. 1, individual inlet openings 7 in these transverse X-directed edge regions are indicated.

[0087] Furthermore, one or more recesses 7 can be arranged between two inlet openings 5 ​​or between two outlet openings 6. An example of such a recess 7 is indicated between inlet openings 5a and 5b. Likewise, one or more recesses 7 can be arranged between an inlet opening 5 or an outlet opening 6 and the flow field 4, as indicated between inlet opening 5b and the flow field 4 or between outlet opening 6c and the flow field 4.

[0088] Finally, one or more recesses 7 can also be arranged in areas located between two inlet openings 5 ​​and the flow field 4, or between two outlet openings 6 and the flow field 4. Such an example is shown between the inlet openings 5b and 5c and the flow field 4, as well as between the outlet openings 6b and 6c and the flow field 4. In some embodiments, these areas offer slightly more space than, for example, between two adjacent inlet openings 5 ​​or two adjacent outlet openings 6, because the cross-section of the inlet openings 5 ​​or outlet openings 6 of a typical bipolar plate often has rounded edges – for example, due to manufacturing processes – as also shown in Fig. 1. Thus, for example, a slightly larger recess 7a can be accommodated in such an area.

[0089] Fig. 2 shows a cross-sectional view of a section of a bipolar plate 1 according to an embodiment of the present disclosure. A coordinate system is also indicated in Fig. 2, which applies accordingly to Figs. 3 to 12.

[0090] The cross-sectional view in Fig. 2 could, for example, be drawn along a cross-sectional surface that runs orthogonally to the transverse direction X in Fig. 1 and passes through the inlet opening 5a. However, Fig. 2 only shows a section located at the end of the bipolar plate 1 shown at the top of Fig. 1. Fig. 2 thus indicates an inlet opening 5, the adjacent edge region 8, and a portion of the flow field 4. The latter is shown in a cutaway view at the right end of Fig. 2. Furthermore, for the sake of clarity, only one recess 7 is shown in Fig. 2, specifically in the first main surface 2. In the example shown in Fig. 2, no recess 7 is arranged in the opposite second main surface 3.

[0091] The bipolar plate 1 of Fig. 2 has a raised area 10 that is thicker (in the stacking direction Z) than the flow field 4. This raised area 10 contains not only the inlet opening 5 but also the recess 7. The recess 7 is thus located in a region of the bipolar plate 1 that, viewed in the stacking direction Z, is further away from a central plane 9 of the bipolar plate 1 than other regions (for example, the flow field 4) of the bipolar plate 1. The recess 7 can be located in a region of the bipolar plate 1 with the greatest possible distance from the central plane 9. In the example of Fig. 2, the recess 7 is designed as a blind recess 7, with walls that run parallel to the stacking direction Z and a bottom that extends in a plane perpendicular to the stacking direction; however, this should not be considered a limitation.

[0092] Fig. 3 shows a cross-sectional view of a section of a bipolar plate 1 according to a further embodiment of the present disclosure, which can be considered a modification of the embodiment according to Fig. 2. In contrast to the embodiment according to Fig. 2, the example of Fig. 3 has a further recess 7 in the second main surface 3 of the bipolar plate 1. The further recess 7 in the second main surface 3 is located at a corresponding position relative to the recess 7 in the first main surface 2, i.e., only the position in the stacking direction Z is different. Alternatively, the positions of the recesses 7 in the first main surface 2 and the second main surface 3 can also differ in the longitudinal direction Y and / or in the transverse direction X.

[0093] Fig. 4 shows a cross-sectional view of a section of a bipolar plate 1 according to a further embodiment of the present disclosure, which can be considered a modification of the embodiment according to Fig. 3. In contrast to the embodiment according to Fig. 3, the recess 7 is designed as a through-opening 7, i.e., as a recess 7 that extends through the entire thickness of the bipolar plate 1. The recess 7 of Fig. 4 can thus be considered as a recess 7 in the first main surface 2 and as a recess 7 in the second main surface 3.

[0094] Fig. 5 shows a cross-sectional view of sections of a bipolar plate 1 and a further bipolar plate 11 according to a further embodiment of the present disclosure. The bipolar plate 1 of Fig. 5 is formed with a recess 7 in the first main surface 2 as shown in Fig. 2, but could alternatively be formed differently. The same applies to the further bipolar plate 11, whereby the two bipolar plates do not necessarily have to be identical in construction. The bipolar plates 1 and 11 are stacked on top of each other. In the example shown, raised areas 10 of the bipolar plates 1 and 11, i.e., the raised area 10 of the first main surface 2 of the bipolar plate 1 and the raised area 10 of the second main surface 3 of the further bipolar plate 11, are in direct contact with each other, while the flow fields 4 are not – at least for the most part – in contact. The recess 7 in the first main surface 2 of the bipolar plate 1 prevents the bipolar plates 1 and 11 from slipping.

[0095] While the arrangement of the recess 7 in the raised area 10 of the bipolar plate 1 according to Fig. 5 ensures that the two bipolar plates 1 and 11 touch in an area directly surrounding the recess 7, an arrangement of the recess 7 in a raised area of ​​the bipolar plate 1 is not mandatory. For example, in Fig. 6, the recess 7 is arranged in a recessed area of ​​the first main surface 2 of the bipolar plate 1, i.e., an area which in this case is closer to a median plane 9 of the bipolar plate 1 than, for example, a surface of the flow field 4. Nevertheless, the bipolar plate 1 and the other bipolar plate 11 touch in the area around the recess 7 because the additional thickness of the other bipolar plate 11 at its second main surface 3 is greater than the recess of the bipolar plate 1 at its first main surface 2.Figure 7 shows a cross-sectional view of sections of a bipolar plate 1 and another bipolar plate 11 according to a further embodiment of the present disclosure. While in the examples of Figures 2 to 6 the recesses 7 are shown as being filled only with ambient air, which can already counteract slippage of the bipolar plate 1 relative to the other bipolar plate 11, slippage of the bipolar plate 1 can be counteracted even better if the at least one recess 7 is at least partially filled with a filling material 12. The bipolar plates 1, 11 shown in Figure 7 can be considered a variant of the bipolar plates 1, 11 shown in Figure 5.A filler material 12, for example in the form of a sphere, made of polyurethane, rubber, and / or ethylene propylene diene monomer rubber or another material, particularly one with a relatively low modulus of elasticity, is inserted into the recess 7 in the first main surface 2 of the bipolar plate 1. In the example shown in Fig. 7, the filler material 12 extends beyond the edge of the recess 7 in the stacking direction Z. Thus, the other bipolar plate 11 rests only on the filler material 12 and does not touch the bipolar plate 1. In other words, the filler material 12 holds the two bipolar plates 1 and 11 at a certain distance, which may be small, for example only about 1 mm or (or down to) a few millimeters. In the example shown in Fig. 7, the bipolar plates 1 and 11 have a substantially constant thickness, i.e., the flow field 4 is not reduced or tapered compared to, for example, the edge region 8.

[0096] Fig. 8 shows a cross-sectional view of a recess 7 and adjacent areas of a bipolar plate 1 according to a further embodiment of the present disclosure. In this example, the recess 7 has the shape of a (concave) hemisphere that is recessed into the first main surface 2. The recess 7 could again be filled only with ambient air or, as in the example shown, with a filling material 12, which in the example of Fig. 8 also has the shape of a hemisphere. The flat surface of the hemisphere of the filling material 12 is aligned flush with the upper edge of the recess 7, i.e., with the first main surface 2 of the bipolar plate 1. For the sake of clarity, the filling material 12 is shown slightly smaller than the recess 7, so that a gap is visible between the filling material 12 and the recess 7. The filling material 12 can, however, completely fill the recess 7, although this is not absolutely necessary.The filler material 12 could also, for example, comprise an adhesive 12, in particular an adhesive 12 that prevents the bipolar plates 1, 11 from slipping relative to each other, but which can optionally be easily removed from the other bipolar plate 11, in particular without leaving any residue. Fig. 9 shows a cross-sectional view of a recess 7 and adjacent areas of a bipolar plate 1 according to a further embodiment of the present disclosure, which can be considered a variant of the embodiment according to Fig. 8. In the example of Fig. 9, however, the filler material 12 is not hemispherical, but essentially spherical and thus extends beyond the edge of the recess 7 or beyond the first main surface 2 of the bipolar plate 1. A further bipolar plate 11 can thus be held at a distance from the bipolar plate 1, similar to the embodiment shown in Fig. 7.

[0097] Fig. 10 shows a cross-sectional view of a recess 7 and adjacent areas of a bipolar plate 1 according to a further embodiment of the present disclosure, which can be considered a further variant of the embodiment according to Fig. 8. In the example of Fig. 10, the filling material 12 is again hemispherical. The recess 7 has the form of a (concave) spherical cap, but this spherical cap is less deep than the thickness of the hemispherical filling material 12 would suggest. The filling material 12 thus again projects beyond the edge of the recess 7 or beyond the first main surface 2 of the bipolar plate 1.

[0098] Fig. 11 shows a cross-sectional view of a recess 7 and adjacent areas of a bipolar plate 1 according to a further embodiment of the present disclosure, which can be considered a variant of the embodiment according to Fig. 9. In the example of Fig. 11, the recess 7 is again hemispherical. The filler material 12, on the other hand, has the shape of an ovoid. In the example of Fig. 11, the ovoid has cross-sections perpendicular to the stacking direction Z, which are smaller than corresponding cross-sections—i.e., at corresponding positions in the stacking direction Z—of the recess 7. That is, the ovoid does not initially fill the recess 7 completely. If another bipolar plate 11 is now stacked on top of the bipolar plate 1, the ovoid filler material 12 can be compressed in the stacking direction Z, so that in the compressed state it essentially assumes a spherical shape, for example, which fills the recess 7.

[0099] Fig. 12 shows a cross-sectional view of a recess 7 and adjacent areas of a bipolar plate 1 according to a further embodiment of the present disclosure, which can be considered a further variant of the embodiment according to Fig. 9. In the example of Fig. 12, the filler material 12 is again spherical. The recess 7, however, is designed as a through-opening 7, as is also the case in Fig. 4. The largest cross-section of the filler material 12 is, however, larger than the cross-section of the recess 7 at the (in Fig. 12) upper edge, i.e., at the first main surface 2 of the bipolar plate 1, so that the filler material 12 protrudes beyond the edge of the recess 7 or beyond the first main surface 2.

[0100] In Fig. 12, another bipolar plate 11 is shown with dashed lines. This plate has a corresponding recess 7 in its second main surface 3. The filling material 12 is partially contained in the recess 7 of bipolar plate 1 and partially in the recess 7 of the other bipolar plate 11, thus keeping the bipolar plates 1 and 11 apart. In this way, slippage of bipolar plate 1 relative to the other bipolar plate 11 can be counteracted particularly effectively. The same applies to other embodiments of bipolar plates 1.

[0101] 11 and filler material 12, provided that one bipolar plate 1 has a corresponding recess 7 on its upper side 2 and the other bipolar plate 11 has a corresponding recess 7 on its lower side 3 (regardless of whether the recesses 7 are designed as through openings 7 or blind recesses 7, and regardless of the shapes of the recesses 7) and the filler material

[0102] 12 can each be partially accommodated in both recesses 7. This could be the case, for example, with two bipolar plates 1, 11, which are designed according to Fig. 3.

[0103] Fig. 13 shows a top view of a recess 7 according to a further embodiment of the present disclosure. While previously mainly recesses 7 have been described which, in top view (i.e., in a plane perpendicular to the stacking direction Z), have circular cross-sections, in principle all other shapes of recesses 7 are also possible, for example, recesses 7 with a rectangular or square cross-section, as shown in Fig. 13. A filling material 12 to be used with such a recess 7 can have a corresponding shape or a different shape. Accordingly, the filling material 12 can completely fill the recess 7, or not.

[0104] Fig. 14 shows a top view of a recess 7 according to a further embodiment of the present disclosure. As in Fig. 13, the cross-section of the recess 7 is not circular, but hexagonal in this example.

[0105] Fig. 15 shows a flowchart illustrating a method according to one embodiment of the present disclosure. After the start 20 of the method, in step 21 a bipolar plate 1 with a plurality of recesses 7 in at least one first principal surface 2 of the bipolar plate 1 is provided. Then, in step 23, (at least) another bipolar plate 11 is placed on the bipolar plate 1 to form a bipolar plate stack (the optional intermediate step 22, shown with dashed lines, and the further optional steps 24 and 25, also shown with dashed lines, are skipped for now). The method can then end (26).

[0106] In one variant of the method, the additional step 22 is also carried out, in which a filling material 12 is inserted into one or more recesses 7 of the bipolar plate 1, for example in such a way that the bipolar plates 1 , 11 are kept at a distance, in particular in such a way that the filling material 12 is not only (partially) received in a recess 7 of the bipolar plate 1, but also (partially) in a recess 7 of the further bipolar plate 11.

[0107] In another variant of the procedure, steps 21 and 23, and optionally step 22, are carried out as described above. Additionally, step 24 is also performed, in which – optionally after transporting the stack of bipolar plates formed from bipolar plate 1 and the additional bipolar plate 11 (and optionally further bipolar plates) – the additional bipolar plate 11 is removed from bipolar plate 1.

[0108] In another variant of the process, steps 21 to 24 are carried out, and additionally, step 25 is performed, in which the filling material 12 is also removed from the bipolar plate 1. If necessary, the bipolar plate 1 can simply be tilted, i.e., rotated about a horizontal axis by a sufficiently large angle (e.g., by 180°), so that the filling material 12 falls or rolls out of the recess(s) 7 without any additional steps, or at least that removal of the filling material 12 is facilitated. Falling out or rolling out is to be expected in particular if the filling material 12, at least in its uncompressed state, does not completely fill the corresponding recess 7 or its cross-sections and / or has a shape with round, especially circular, cross-sections, in particular the shape of a sphere, spherical cap, hemisphere, or ovoid.

[0109] The filling material 12 can then be recycled or reused if necessary.

[0110] Fig. 16 shows an exemplary enlarged cross-sectional view of a recess 7 and adjacent areas of a bipolar plate 1. Fig. 16 also shows two embodiments. The left half of Fig. 16 illustrates an embodiment that has a small surrounding area 13 directly adjacent to the edge of the recess 7. This surrounding area is indicated by a dotted line 13. In this surrounding area

[0111] 13 the first main surface 2 of the bipolar plate 1 has a higher roughness than outside the surrounding area 13 (shown in Fig. 16 to the left of the surrounding area 13).

[0112] In the right half of Fig. 16, a further embodiment is illustrated, in which a small surrounding area 14 directly adjacent to the edge of the recess 7 has a rounded shape.

[0113] 14. Further outwards (in Fig. 16 on the right) the rounding 14 transitions into the first main surface 2 of the bipolar plate 1.

[0114] Both the area 13 with higher roughness and the rounding 14 can, for example, arise due to manufacturing processes when producing the recess 7.

[0115] While Fig. 16 shows a region 13 with higher roughness in the left half and a rounding 14 in the right half, the surrounding region 13 with higher roughness can extend around the entire circumference of the recess 7. Likewise, the surrounding region 14 with rounding can extend around the entire circumference of the recess 7 instead. Furthermore, embodiments are possible in which the recess 7 is surrounded around its entire circumference by a rounding 14 that also has increased roughness.

[0116] A design with an area 13 of increased roughness and / or a rounding 14 is possible for all recesses 7 to which the present disclosure refers, and is therefore not limited to the shape of the recess 7 shown in Fig. 16.

[0117] While at least one exemplary embodiment has been described above, it should be noted that a large number of variations exist. It should also be noted that the described exemplary embodiments are merely non-limiting examples, and it is not intended to restrict the scope, applicability, or configuration of the devices and methods described herein. Rather, the preceding description will provide guidance for those skilled in the art in implementing at least one exemplary embodiment. It is understood that various modifications to the function and arrangement of the elements described in an exemplary embodiment can be made without derogating from the subject matter defined in the appended claims and their legal equivalents.The features described herein may be combined with one another in any way, unless expressly excluded or technically impossible. Likewise, features described primarily in connection with one aspect disclosed herein may also represent features of the other aspects disclosed herein. Furthermore, all aspects and features disclosed herein, either individually or in combination, are to be considered aspects of the present invention.

[0118] List of reference signs

[0119] 1 plate-shaped structure or bipolar plate

[0120] 2 first main area

[0121] 3 second main area

[0122] 4 Flow field

[0123] 5 (a, b, c) Entrance openings

[0124] 6 (a, b, c) Exit openings

[0125] 7, 7a Exemptions

[0126] 8 border area(s)

[0127] X transverse direction

[0128] Y Longitudinal direction

[0129] Z Stacking direction

[0130] 9 Middle level

[0131] 10 Raised surface section of the plate-shaped structure or bipolar plate

[0132] 11. Another plate-shaped structure or another bipolar plate

[0133] 12 Filling material

[0134] 13. Area with higher roughness

[0135] 14 Surrounding area with rounding

[0136] 20 to 26 process steps

Claims

REQUIREMENTS 1. Plate-shaped structure (1) for a fuel cell, wherein the plate-shaped structure (1) has: a flow field (4); Inlet openings (5) and outlet openings (6) for an anode gas and / or a cathode gas and / or a coolant; and a plurality of recesses (7) in at least one first principal surface (2) of the plate-shaped structure (1), which are configured to counteract a slippage of the plate-shaped structure (1) relative to another plate-shaped structure (11) when the plate-shaped structure (1) and the other plate-shaped structure (11) are stacked on top of each other, and / or to accommodate a filling material (12) to counteract a slippage of the plate-shaped structure (1) relative to another plate-shaped structure (11) and / or to keep the plate-shaped structure (1) and the other plate-shaped structure (11) apart when the plate-shaped structure (1) and the other plate-shaped structure (11) are stacked on top of each other.

2. Plate-shaped structure (1) according to claim 1, wherein the inlet openings (5) and outlet openings (6) are arranged at opposite ends of the plate-shaped structure (1).

3. Plate-shaped structure (1) according to claim 1 or 2, wherein at least two recesses (7) of the plurality of recesses (7) are arranged in a first edge region (8) of the plate-shaped structure (1) and / or at least two recesses (7) of the plurality of recesses (7) are arranged in a second edge region (8) of the plate-shaped structure (1) opposite the first edge region (8).

4. Plate-shaped structure (1) according to one of the preceding claims, wherein at least one of the plurality of recesses (7) is arranged between adjacent inlet openings (5) and / or at least one of the plurality of recesses (7) is arranged between adjacent outlet openings (6), and / or wherein at least one of the plurality of recesses (7) is arranged between the flow field (4) and one or more inlet openings (5), and / or at least one of the plurality of recesses (7) is arranged between the flow field (4) and one or more outlet openings (6).

5. Plate-shaped structure (1) according to one of the preceding claims, wherein the majority of the recesses (7) are arranged in such areas of the first main surface (2) of the plate-shaped structure (1) which, viewed in the stacking direction (Z), are furthest apart from a central plane (9) of the plate-shaped structure (1).

6. Plate-shaped structure (1) according to one of the preceding claims, wherein at least one of the plurality of recesses (7) has a shape that substantially corresponds to the shape of a concave hemisphere or spherical cap and / or has a cross-section that defines a polygon or a hexagon.

7. Plate-shaped structure (1) according to one of the preceding claims, wherein a filling material (12) is received through at least one of the plurality of recesses (7) and wherein the filling material (12) protrudes from the first main surface (2) of the plate-shaped structure (1).

8. Plate-shaped structure (1) according to one of the preceding claims, wherein a filler material (12) is received by at least one of the plurality of recesses (7) and wherein the filler material (12) comprises adhesive, polyurethane, rubber and / or ethylene propylene diene monomer rubber.

9. Plate-shaped structure (1) according to one of the preceding claims, wherein a filling material (12) is received by at least one of the plurality of recesses (7) and wherein the filling material (12) comprises a material which is in a stacked arrangement of the plate-shaped structure (1) and the further plate-shaped structure (11) counteracts a slippage of the plate-shaped structure (1) relative to the further plate-shaped structure (11) more than would be the case in a stacked arrangement of the plate-shaped structure (1) and the further plate-shaped structure (11) without filling material (12).

10. Plate-shaped structure (1) according to one of the preceding claims, wherein a filling material (12) is received by at least one of the plurality of recesses (7) and wherein the filling material (12) has a shape adapted to the shape of the at least one recess (7), and / or wherein the filling material (12) substantially has the shape of a hemisphere, a sphere or an ovoid and / or wherein a maximum cross-section of the filling material (12) is larger than a cross-section of the at least one recess (7) and / or wherein the filling material (12) has a rough surface and / or wherein the filling material (12) is coated and / or wherein the filling material (12) has a cross-section defining a polygon or a hexagon.

11. Plate-shaped structure (1) according to one of the preceding claims, wherein the plate-shaped structure (1) has a plurality of recesses (7) in a second main surface (3) of the plate-shaped structure (1), wherein the plurality of recesses (7) in the second main surface (3) of the plate-shaped structure (1) are arranged at positions that correspond to positions in the first main surface (2) of the plate-shaped structure (1) at which the plurality of recesses (7) in the first main surface (2) of the plate-shaped structure (1) are arranged.

12. Plate-shaped structure (1) according to one of the preceding claims, wherein the plate-shaped structure (1) has a rounding (14) around at least one of the plurality of recesses (7) in a locally limited surrounding area (13, 14), in particular around several of the plurality of recesses (7) in locally limited surrounding areas (13, 14), in particular around all of the plurality of recesses (7) in locally limited surrounding areas (13, 14).

13. Plate-shaped structure (1) according to one of the preceding claims, wherein the plate-shaped structures (1) and / or the further plate-shaped structure (11) has a bipolar plate (1, 11).

14. Stack of plate-shaped structures (1 , 11) comprising a plate-shaped structure (1) according to one of the preceding claims and at least one further plate-shaped structure (11).

15. Method for handling at least two plate-shaped structures (1 , 11), wherein the method comprises: Providing (21) a plate-shaped structure (1) according to any one of claims 1 to 13; and Placing (23) another plate-shaped structure (11) on the plate-shaped structure (1).

16. The method of claim 15, further comprising: Inserting (22) filler material (12) at least partially into a recess (7) of the plurality of recesses (7).

17. The method of claim 16, further comprising: Removal (24) of the further plate-shaped structure (11) from the plate-shaped structure (1); and Removing (25) the filling material (12) from the plate-shaped structure (1).

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