Bipolar plate, bipolar plate system, end plate and fuel cell

Abstract

The invention relates to a bipolar plate (210) for a fuel cell (1), the bipolar plate (210) extending in a longitudinal direction (L) and in a width direction (B), the longitudinal direction (L) and the width direction (B) being in particular perpendicular to one another, the bipolar plate (210) having a plurality of perforations (240), the perforations (240) having an outer contour, wherein the outer contour of the passage (240) is formed in each case by a mounting passage (242) and by at least one flow passage (244), the mounting passage (242) forming a circular arc-shaped part of the outer contour of the passage (240), and the mounting passage (242) being designed to receive a fastening means (9).

Description

Technical Field

[0001] The invention relates to a bipolar plate, a bipolar plate system, an end plate and / or a fuel cell. Background Art

[0002] Fuel cells are already known from the prior art. Fuel cells are used, in particular, to release electrons by using reactions in order to thereby generate electric current or to be able to provide energy. As fuel, different fluids, such as hydrogen, can be used. However, a problem with known systems is that the fuel cell consists of a plurality of cells, which are each separated from one another by bipolar plates. The cells are mostly stacked and covered on the end sides by end plates in order to thereby achieve a compact design. The cells are fixed to one another and to the end plates mostly by external fastening means. However, the bipolar plates and the end plates are thus subjected to large bending stresses and / or this results in a high structural space requirement. Summary of the invention

[0003] It is therefore an object of the present invention to provide an arrangement which saves construction space but nevertheless enables reliable fastening of the components of a fuel cell.

[0004] This object is achieved by a bipolar plate according to claim 1, by a bipolar plate system according to claim 4, by an end plate according to claim 8 and by a fuel cell according to claim 10. Further advantages, features and embodiments emerge from the dependent claims, the description and from the drawings.

[0005] According to the present invention, a bipolar plate is provided. The bipolar plate is used to constitute or can constitute a part of a fuel cell. The bipolar plate extends in the longitudinal direction and in the width direction, wherein the longitudinal direction and the width direction are particularly perpendicular to each other, wherein the bipolar plate has a plurality of perforations, wherein the perforations have an outer contour, wherein the outer contour of the perforations is respectively constituted by a mounting perforation and at least one flow perforation, wherein the mounting perforations constitute a circular segment-shaped part of the outer contour of the perforations, and wherein the mounting perforations are designed to accommodate a fastening mechanism or a connecting mechanism. The bipolar plate is a component and / or can be arranged in a fuel cell or used therein. In particular, an MEA is respectively arranged between two bipolar plates. For the purposes of the present invention, "MEA" should be understood as a membrane-electrode unit. Therefore, the bipolar plate is used to be able to guide fuel, especially hydrogen, and / or oxygen and / or combustion products, especially fluids, such as water or water vapor, from and / or to the MEA, and at the same time at least partially limit the accommodation volume for the MEA. In addition, the bipolar plate can be used in particular for conducting electrons. The bipolar plate is at least partially made of a conductive material, and / or made of plastic and / or at least partially made of an insulating material. Therefore, the bipolar plate can especially form part of a stack or "stack" of a fuel cell. The bipolar plate extends in particular in the longitudinal direction and in the width direction. The longitudinal direction is especially the direction in which the bipolar plate has its maximum main dimension. On the contrary, the width direction can especially be the direction in which the width of the bipolar plate is measured. The height direction can be especially perpendicular to the longitudinal direction and / or the width direction. The height direction can especially be the direction in which the material strength of the bipolar plate is measured. It is particularly suitable that the longitudinal direction and the width direction are perpendicular to each other. In addition, it is preferred that the longitudinal direction, the width direction and the height direction can especially be perpendicular to each other respectively. In other words, the longitudinal direction, the width direction and the height direction can form a rectangular coordinate system with each other. The bipolar plate includes a plurality of perforations. The perforations here especially completely penetrate the bipolar plate, wherein the main extension direction of the perforations is especially the height direction. In other words, the perforations can penetrate the bipolar plate in the height direction. It is thus possible to guide a mechanism, in particular a fastening structure and / or a connecting mechanism, and / or a fluid through the bipolar plate. In other words, the through-hole can therefore be used to enable the fluid to flow from one side of the bipolar plate to the other side of the bipolar plate and also simultaneously provide a receiving space for a fastening mechanism or a tensioning mechanism. In particular, the flow through-hole of the through-hole is considered to be used for a fluid line. The through-hole itself is here constituted by being a component of the flow through-hole and at least also by another component called the mounting through-hole. The mounting through-hole is used here to accommodate a fastening mechanism or a connecting mechanism, which may also be a tensioning mechanism or a connecting mechanism, so as to thereby achieve the "stacking" or tensioning of the stack of bipolar plates and / or fuel cells. In other words, the through-hole can therefore be constituted by the combination of at least one flow through-hole of the mounting through-hole.Suitably, the bipolar plate basically has a plurality of perforations, each of which has at least one flow perforation and an installation perforation. The perforation is arranged or configured so that it forms an outer contour on the bipolar plate. The outer contour is in particular the outer edge of the perforation on the surface of the edge of the bipolar plate (especially in the height direction). The outer contour of a perforation or a plurality of perforations is at least partially formed by the flow perforation and at least partially by the installation perforation. In other words, the edge of the perforation is at least partially formed by the installation perforation and at least partially also by the flow perforation. The installation perforation in particular forms a circular segment-shaped portion of the outer contour of the perforation. In other words, at least a portion of the external perforation is therefore formed by a circular segment, which also limits the installation perforation at the same time. Alternatively, the perforation can therefore have a partial circular segment-shaped segment, which is just formed by the installation perforation. This makes it possible to achieve a particularly low-cut effect and production-friendly and compact design of the mounting lead-through, in particular adapted to fastening or connecting means, in particular fastening and / or connecting means in the form of screws. A screw in the context of the invention can in particular be a fastening and / or connecting means having an actuating head and / or an actuating section and further having an external thread and / or an internal thread, which is introduced in particular into the shank section.

[0006] In a preferred embodiment, the bipolar plate has a flow area, wherein the flow area is used in particular to delimit a fluid volume, wherein the fluid volume is in particular connected to or can be connected to the fluid of at least two through-holes. The flow area is in particular an area of ​​the bipolar plate or one or more surfaces of the bipolar plate that are located outside and are surrounded in the height direction, and the area or the surface is in contact with or can be in contact with the MEA fluid. Therefore, the flow area can constitute or include a surface on the bipolar plate. Suitably, the bipolar plate has not only a flow area formed by a surface surrounded in the positive height direction, but also a flow area formed by a surface surrounded in the negative height direction. The flow area is used in particular to delimit a fluid volume that is connected to the MEA and / or to at least partially provide a volume in which the MEA is arranged. Therefore, the flow area in particular encloses a fluid volume that is connected to or can be connected to the fluid of at least two through-holes of the bipolar plate. This is particularly important when sealing elements are subsequently provided and / or are arranged on the bipolar plate, which sealing elements allow a fluid flow from one aperture to the flow region and from the flow region to another aperture. As a result, apertures, in particular flow penetrations of apertures, which are fluidically connected to the flow region or the fluid volume, can be used to enable a fluid inflow and outflow into the fluid volume.

[0007] Expediently, the installation passage and the flow passage of one or more passages penetrate the bipolar plate, thereby making it possible to achieve a particularly simple passage of the fastening means and / or the connecting means and the flow fluid through the bipolar plate.

[0008] Advantageously, the flow passage is designed such that it extends in a plane spanned by the longitudinal direction and the width direction from the installation passage to the flow region. This allows a particularly flow-technically advantageous design of the flow passage to be achieved.

[0009] Suitably, the circular segment-shaped part of the installation penetration constitutes at least 51%, preferably at least 65%, and particularly preferably at least 75% of the circle. In other words, the circular segment-shaped part can constitute at least 51%, preferably at least 65%, and particularly preferably at least 75% of the complete circle. By the design scheme that at least 51% is constituted by the circular segment-shaped part of the installation penetration, the position fixation of the fastening / connecting mechanism accommodated in the circular segment-shaped part or the installation penetration can be achieved. In other words, by this design scheme, the position fixation of the fastening / connecting mechanism in the installation penetration is particularly guaranteed or at least provided in an emergency, so that in particular, the bipolar plate is prevented or can be prevented from sliding relative to the fastening / connecting mechanism in the longitudinal direction and the width direction plane. In order to further improve the form-fitting fixation, the circular segment-shaped part should constitute at least 65%, preferably at least 75% of the complete circle. It is thus possible to further improve the form-fitting fixation between the bipolar plate and the fastening / connecting mechanism to achieve better accuracy of the position fixation. By this type of positive locking of the bipolar plates relative to the fastening / connecting means, a particularly simple assembly can be achieved. It is thus particularly possible to thread the individual bipolar plates onto the fastening / connecting means afterwards, which simplifies assembly.

[0010] However, preferably, the circular segment-shaped part of the mounting aperture forms a maximum of 98%, preferably a maximum of 90%, and particularly preferably a maximum of 80% of the circle. The missing part that forms a complete circle here particularly belongs to the flow aperture. In other words, this design can therefore ensure that there is enough space for the flow aperture in the aperture so that a sufficient flow surface or flow capability is provided.

[0011] Preferably, the bipolar plate has a flow groove, in particular in a flow region of the bipolar plate or in the flow region, wherein the flow groove ends and / or starts in particular in the through-hole. In other words, the bipolar plate can have a groove in a surface that delimits the bipolar plate in the height direction, which can promote and / or realize the fluid flow. The groove is particularly referred to as a flow groove here. Suitably, the flow groove extends on the bipolar plate or is arranged on the bipolar plate so that the flow groove ends and / or starts in the through-hole, in particular in the flow through-hole. In other words, the groove extends until it enters the flow through-hole or the through-hole. This makes it possible to achieve a particularly advantageous attachment of the flow groove in terms of flow technology. By providing a flow groove, it is particularly possible to achieve blockage of the fluid and also to achieve uniform delivery of the fluid to the MEA.

[0012] In a preferred embodiment, the flow channel is formed by straight and / or rectangular sections and / or the flow channel extends in a meandering manner. By using only straight and / or rectangular or right-angled sections and / or in a meandering design, the flow channel has a particularly large extension. This allows a particularly effective and uniform transport of the fluid into the MEA and / or the discharge of the fluid from the MEA into the flow channel. By means of the meandering design of the flow channel, in particular, a particularly long flow length of the channel can also be achieved, thereby achieving a particularly uniform transport or discharge of the fluid into and / or out of the MEA.

[0013] Advantageously, the portion of the outer contour of the perforation formed by the flow perforation is spaced further from the center of gravity of the perforation or the center point of the circular segment-shaped portion than the portion of the outer contour of the perforation formed by the mounting perforation. In other words, the flow perforation can extend away from the otherwise circular mounting perforation like a projection. Alternatively or additionally, preferably, the mounting perforation forms all circular segment-shaped portions of the perforation and / or is formed only by circular segment-shaped portions, in particular all having the same center point. By this type of design of the perforation, some perforations, most of the perforations and / or all perforations, a particularly good fluid guiding feasibility can be achieved. The center point of the circular segment-shaped portion is in particular a point around which the radius of the circular segment-shaped portion is determined, or a point with the same spacing from all points of the circular segment-shaped portion.

[0014] Preferably, the bipolar plate has a width-to-length ratio that is particularly less than or equal to 1 to 3, wherein the bipolar plate has a perforation, particularly a plurality of perforations, in its middle region along the longitudinal direction. In other words, the ratio of the size of the bipolar plate in the width direction to the size of the bipolar plate in the longitudinal direction can be less than or equal to 1 to 3. If such a ratio exists, a perforation, particularly a plurality of perforations, can be provided in the middle region along the longitudinal direction. The middle region along the longitudinal direction is particularly the following region of the bipolar plate along the longitudinal direction, which extends from the ideal center point in the longitudinal direction by + / -25%, preferably + / -15%, and particularly preferably + / -10% and more particularly preferably + / -5% of the maximum length of the bipolar plate along the longitudinal direction. The center point of the bipolar plate is particularly the volume center of gravity or center of gravity of the bipolar plate. By providing a perforation, particularly a plurality of perforations in the middle region, as described above and below, a particularly good tensioning feasibility of the bipolar plate can be achieved in particular. In particular, the bending moment caused by tensioning can be avoided or reduced by providing a perforation in the middle region. Advantageously, all of the passages are designed as described above or below, so that the passages have in particular a mounting passage and a flow passage, wherein in particular the fastening / connecting means are guided or can be guided through the flow passage.

[0015] Another aspect of the invention can relate to the use of a bipolar plate in / for a fuel cell.

[0016] Another aspect of the present invention can relate to a bipolar plate system. The bipolar plate system in particular includes a bipolar plate as described above and / or below and a sealing element, in particular a sealing ring. Suitably, the sealing element rests on the bipolar plate, wherein the sealing element at least partially follows or can follow the circular segment-shaped portion of the outer contour of the through-hole. Therefore, the bipolar plate system in particular includes at least one sealing element, which can be configured as a seal. A seal is understood as a sealing element that is closed in itself. In other words, the seal is therefore a sealing element without ends. The sealing element rests in particular on the bipolar plate, which can occur in particular through direct contact between the sealing element and the bipolar plate. Suitably, the contact or contact area of ​​the sealing element and the bipolar plate constitutes a self-closed contour. In other words, the sealing element can therefore always contact the bipolar plate along its extension. Suitably, the sealing element at least partially follows the circular segment-shaped portion or a circular segment-shaped portion of the outer contour of the through-hole. In particular, following is understood to mean that the projection of the sealing element and the projection of the outer contour onto a plane extending through the longitudinal direction and the width direction overlap, and / or the extent of the sealing element and the outer contour is identical at least in the following region, and / or the sealing element bears at least in sections against a circular segment-shaped portion of the outer contour. By such following of the sealing element in a circular segment-shaped circle of the outer contour of the feedthrough, it is possible in particular to achieve a particularly short length of the sealing element and also a high sealing effect.

[0017] In an advantageous embodiment, the sealing element follows at least 40%, preferably at least 60%, and particularly preferably at least 80%, and particularly preferably at least 90%, and more particularly preferably at least 97% of the circular segment-shaped part of the outer contour of the perforation. Alternatively or additionally, the sealing element preferably follows at least 40%, preferably at least 60%, and particularly preferably at least 80%, and particularly preferably at least 90%, and more particularly preferably at least 97% of the outer contour of the perforation. By following at least 40% of the circular segment-shaped part and / or the entire outer contour of the perforation, a particularly simple installation can be achieved. On the contrary, if at least 60% or at least 80% of the circular segment-shaped part and / or the entire outer contour of the outer contour of the perforation is followed by the sealing element, a particularly good sealing effect can be achieved. On the contrary, if 90% of the outer contour or circular part is followed by the sealing element, a particularly good mechanical support capability around the perforation can be achieved thereby. This capability is particularly noteworthy because when the bipolar plate is tensioned by means of a fastening / connecting mechanism guided through the perforation: the contact force or tensioning force can be reliably conducted directly via the sealing element. In particular, a circular segment-shaped portion that follows the outer contour of the through-hole or the outer contour of the through-hole by at least X percentage is understood to mean that at least X percentage of the projection of the outer contour of the circular segment-shaped portion or the entire outer contour onto a plane extended by the longitudinal direction and the width direction coincides with the projection of the sealing element in the plane, and / or the sealing element at least abuts on X percentage of the circular segment-shaped portion of the outer contour or the outer contour.

[0018] Advantageously, the sealing element projects into the perforation or into one perforation and / or into at least two perforations. In this case, in particular only the perforation is decisive, which has a mounting perforation and a flow perforation and / or through which the fastening / connecting means is guided and / or which is used or designed to accommodate the fastening means. By projecting into the perforation, it is in particular possible that the seal can be arranged between the fastening / connecting means and the peripheral edge of the perforation, so that contact between the fastening / connecting means and the perforation is prevented. In other words, the sealing element can thus be used to bring about an electronic insulation between the fastening / connecting means and the bipolar plate.

[0019] The sealing element expediently consists, in particular, of an insulating material.

[0020] Advantageously, the bipolar plate system has a plurality of sealing elements, wherein the sealing elements at least partially follow the extension of the outer contour of at least one perforation, and / or wherein each perforation is surrounded by the outer contour of the sealing element. Decisive for this are, in particular, perforations which have a mounting perforation and a flow perforation and / or which are configured to accommodate a fastening / connecting mechanism. By virtue of the perforations and / or at least one of the perforations being surrounded by the outer contour of the sealing element, it is possible to achieve that the perforations can be used for guiding fluids into and / or out of the fluid volume. In particular, the perforation being surrounded by the outer contour of the sealing element means that, when projected onto a plane formed by the longitudinal direction and the width direction of the surrounding sealing element and perforation, the outer contour of the projection of the sealing element or the outer edge of the contour surrounds and / or contains the outer contour of the perforation.

[0021] Preferably, the sealing element is fixed to the bipolar plate in a material-matched and / or irreversible manner, and / or the sealing element is manufactured by a screen printing method. The advantage of using a screen printing method is in particular the low-cost manufacture of a bipolar plate system with a sealing element. By fixing the sealing element to the bipolar plate, in particular a simple installation of the bipolar plate system can be achieved. In order to achieve the fixing, the fixing is implemented in a material-matched manner, for example by bonding and / or by a screen printing method. Suitably, the sealing element is irreversibly fixed to the bipolar plate, so that the connection between the sealing element and the bipolar plate can only be achieved by destroying the connection. In this way, a particularly high sealing effect can be achieved.

[0022] Advantageously, the sealing element is arranged on the bipolar plate so that the sealing element forms a closed contour on the bipolar plate, wherein at least two flow perforations, especially different perforations and / or flow areas of the bipolar plate are advantageously arranged in the closed contour. By arranging the closed contour of the sealing element on the bipolar plate, a particularly high sealing effect can be achieved. By arranging at least two flow perforations in the closed contour, a particularly good delivery and export of the fluid to the sealed area can be achieved. In particular, the flow area of ​​the bipolar plate and / or at least the outlet or contour of the flow perforations, especially different perforations, are also arranged in the sealed area or in the closed contour. It is thus possible to achieve a particularly uniform or targeted delivery and export of the fluid to the flow area of ​​the bipolar plate.

[0023] In a preferred embodiment, the bipolar plate system includes a fastening / connecting mechanism, wherein the fastening / connecting mechanism guides through the through-hole, especially the installation through-hole of the through-hole, wherein the fastening / connecting mechanism especially contacts the sealing element. The insulation between the fastening / connecting mechanism and the bipolar plate can be achieved by contacting the sealing element with the fastening / connecting mechanism. By guiding the fastening / connecting mechanism through the through-hole, especially guiding the installation through-hole through the through-hole, the tensioning and installation feasibility of the bipolar plate that is particularly simple and saves structural space can be achieved. Suitably, the fastening / connecting mechanism has an operating area, especially a head, and has an installation area, wherein the installation area constitutes a thread. Suitably, the installation area is formed in the rod area of ​​the fastening / connecting mechanism and / or around the rod area of ​​the fastening / connecting mechanism. The fastening / connecting mechanism extends in particular in the height direction. In other words, the main extension direction of the fastening / connecting mechanism is therefore advantageously parallel to the height direction. Particularly preferably, the fastening / connecting mechanism guides through each through-hole of the bipolar plate having an installation through-hole and a flow through-hole. It is thus possible to achieve a particularly uniform tensioning feasibility of the bipolar plate.

[0024] In a preferred embodiment, the fastening / connecting mechanism has a flow channel extending along a height direction or the height direction, wherein the flow channel is fluidically connected to the flow through-portion that together constitutes the through-portion, and the fastening / connecting mechanism is guided through the through-portion. For example, the fastening / connecting mechanism can be a Banjo joint, wherein the flow channel can be formed in the Banjo joint. Alternatively, the flow channel can also be preferably introduced into the fastening / connecting mechanism externally, for example, through an external groove. The flow channel extends in particular in the height direction. In other words, the flow channel can therefore provide a fluid conveying capability in the height direction. In particular, the flow channel of the fastening / connecting mechanism is fluidically connected to the flow through-portion, so that the fluid can flow from the flow channel into the flow through-portion. This can provide a particularly effective flow feasibility.

[0025] In an alternative or additional preferred embodiment, the bipolar plate system comprises a plurality of fastening / connecting means, wherein the plurality of fastening / connecting means are led through a respective perforation, wherein the perforation in particular comprises a mounting perforation and / or a flow perforation. This makes it possible in particular to achieve a particularly uniform stress distribution, so that ultimately a particularly high sealing effect can be achieved, while at the same time, however, valuable structural space can be saved.

[0026] A further aspect of the invention can relate to the use of a bipolar plate system and / or a fastening or connecting device in / for a fuel cell.

[0027] Another aspect of the present invention can relate to an end plate for a fuel cell, wherein the end plate extends in a longitudinal direction and in a width direction, wherein the end plate has two tensioning areas that are apart from each other, in particular in the longitudinal direction, wherein the bending stiffness of the end plate, in particular between the mounting areas, is variable, advantageously decreasing toward the mounting areas. In particular, the end plate extends in a longitudinal direction and in a width direction, wherein the longitudinal direction of the end plate can correspond to the longitudinal direction described above and below, and / or the width direction can correspond to the width direction described above and below. The longitudinal direction of the end plate is in particular the direction in which the end plate has its largest main dimension, and / or the length of the end plate is determined in said direction. Conversely, the width direction is in particular the direction in which the width of the end plate is determined, and / or the end plate has its second largest main dimension in said direction. The longitudinal direction and the width direction can in particular be perpendicular to the height direction, wherein the height direction is in particular oriented parallel and / or coincident with the height direction described above and / or below. The end plate is in particular used for being arranged in a fuel cell, and in particular constituting the distal end of the fuel cell in the height direction. In order to achieve the installation of the end plate, the end plate has in particular two installation areas that are far away from each other. The installation area is in particular the following area, which is used to provide force transmission to the end plate. Suitably, the following area is provided between the two installation areas, in which the end plate has a variable bending stiffness. In particular, the area with variable bending stiffness is expanded here so that the area includes and / or constitutes an intermediate area in the longitudinal direction of the end plate. Here, the middle area of ​​the end plate is determined in the same way as the middle area of ​​the bipolar plate. Suitably, the bending stiffness of the area located between the installation areas is configured so that its bending stiffness decreases toward the installation area. Therefore, the bending stiffness is the greatest in particular in the area that is farthest away from the installation area in the longitudinal direction. Basically, the end plate is also called the top plate for the purposes of the present invention.

[0028] In an advantageous embodiment, the end plate has an arcuate reinforcing rib, wherein the arcuate reinforcing rib extends in particular parallel to the longitudinal direction. The arcuate reinforcing rib expediently has a variable height in the longitudinal direction. The arcuate reinforcing rib is designed in particular such that it has a largest main dimension parallel to the longitudinal direction, in order to thereby provide a particularly good absorption of bending stresses.

[0029] Suitably, the end plate, in particular the mounting region of the end plate, has a fixing penetration. It is particularly preferred that the fastening / connecting means extend through the fixing penetration, wherein the fastening / connecting means can in particular also extend through one or some of the penetrations of the bipolar plate.

[0030] Another aspect of the invention can relate to the use of an end plate in / for a fuel cell.

[0031] Another aspect of the present invention can relate to a fuel cell. Suitably, the fuel cell comprises at least one bipolar plate, preferably a plurality of bipolar plates, in particular a bipolar plate as described above and / or below. Alternatively or additionally preferably, the fuel cell can also relate to a bipolar plate system, preferably a plurality of bipolar plate systems and / or a bipolar plate system with a plurality of bipolar plates and / or fastening / connecting mechanisms and / or sealing elements, in particular as described above and / or below. Furthermore, alternatively or additionally preferably, the fuel cell can also have at least one end plate or two end plates, in particular an end plate as described above and / or below.

[0032] In a preferred embodiment of the fuel cell, a cavity is formed between and / or in two bipolar plates, which cavity is partially delimited by a flow region of one or both bipolar plates, wherein a fluid reaches or can reach the cavity through one of the perforations of the bipolar plate, in particular through the flow perforation, and / or wherein a fluid leaves / can leave the cavity through one of the perforations of the bipolar plate, in particular through the flow perforation. In other words, the flow region of the bipolar plate can thus be fluidically connected to the flow perforation of one perforation and the flow perforation of another perforation. This makes it possible to achieve a particularly effective and simple possibility of contacting the fluid with the flow region via the flow perforation.

[0033] In a preferred development, the MEA is arranged in the cavity. MEA is understood here as a membrane electrode unit. This allows a particularly compact design of the fuel cell to be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further advantages and features of the invention emerge from the following description with reference to the drawings. Individual features of the illustrated embodiments can also be used in other embodiments, unless this is explicitly excluded.

[0035] The accompanying drawings show:

[0036] Figure 1 A bipolar plate is shown;

[0037] Figure 2 A bipolar plate system and / or a bipolar plate are shown;

[0038] Figure 3 A view showing an alternative design of a bipolar plate;

[0039] Figure 4 A bipolar plate system having a bipolar plate and a fastening mechanism is shown;

[0040] Figure 5 A fuel cell having an end plate and a plurality of bipolar plates and a bipolar plate system is shown; and

[0041] Figure 6 An isometric view of the end plate is shown. DETAILED DESCRIPTION

[0042] exist Figure 1 An isometric view of the bipolar plate 210 is shown in FIG. The bipolar plate 210 has a plurality of penetrations 240 extending in a height direction H. The penetrations include mounting penetrations 242 and flow penetrations 244, respectively. The mounting penetrations 242 each have an arc-shaped portion and / or an arc-shaped portion constituting the outer contour of the penetration 240. The mounting penetration 242 is configured to accommodate a fastening mechanism or a connecting mechanism, and the bipolar plate has a width-to-length ratio of less than or equal to 1 to 3, wherein in a central region along the longitudinal direction L, a plurality of penetrations 240 are arranged in the bipolar plate 210. This enables a particularly uniform tension distribution on the bipolar plate 210 to be formed.

[0043] exist Figure 2 , an isometric view of bipolar plates 210 can be seen, which are arranged one above the other in the height direction H. A sealing element 310 is arranged between the bipolar plates 210. In other words, Figure 2 2. The bipolar plate system 300 can also be seen in FIG. As can be seen from the bipolar plate 210 that is the highest in the height direction H, a plurality of sealing elements 310 are fixed to the bipolar plate. The sealing elements 310 surround the perforations 240, respectively. Each of the perforations 240 includes at least one mounting perforation 242 and a flow perforation 244. The sealing element 310 follows at least 60% of the arc-shaped portion of the outer contour of each perforation 240. The arc-shaped portion of the mounting perforation 242 constitutes at least 65% of the circle of the corresponding perforation 240. The flow perforation 244 is configured here so that the flow perforation is configured in a manner pointing to the flow area 252. The flow area 252 is also surrounded by the sealing elements 310. Each sealing element 310 at least partially extends into one perforation 240 or two perforations 240, that is, at least partially extends into the mounting perforation 242. This makes it possible to achieve particularly good insulation of the fastening means 9 which can be accommodated in the mounting lead-through 244, as for example in Figure 4 As shown in .

[0044] exist Figure 3 , a view of a bipolar plate 210 is shown, wherein the bipolar plate 210 has six perforations 240 extending in the height direction H. The width direction B and the longitudinal direction L are perpendicular to the height direction H. A flow groove 250 extends from a perforation 240 arranged at the lower left to a perforation 240 arranged at the upper right, which flow groove leads through a flow region 252. The flow groove 250 is arranged in a meandering shape here.

[0045] The flow region 252 is surrounded by a sealing element 310 , which also surrounds the two passages 240 .

[0046] exist Figure 4 3 shows a bipolar plate system 300. The bipolar plate system 300 includes a plurality of sealing elements 310 and a plurality of bipolar plates 210 and a fastening mechanism 9. The fastening mechanism 9, which can also be referred to as a connecting mechanism, extends in a height direction H. Figure 4 As can be seen in the figure, a plurality of sealing elements 310 contact the bipolar plate 210 and the fastening means 9. The fastening means 9 is designed in this case so that the connection means has a flow channel extending in the height direction H, wherein the flow channel is fluidically connected to the flow passage 244 of the corresponding passage 240. As a result, a particularly good and advantageous fluid supply and / or discharge can be performed via the fastening means 9.

[0047] exist Figure 5 , a fuel cell 1 is shown, wherein the fuel cell 1 has a plurality of fastening means 9 which can also be referred to as connecting means and a plurality of bipolar plates 210 and / or bipolar plate systems 300 . The fuel cell 1 is delimited in height direction H at least in sections by end plates 500 .

[0048] exist Figure 6 5 . The end plate 500 extends in a longitudinal direction L and in a width direction B, wherein the end plate 500 has mounting areas 502 that are spaced apart from one another in the longitudinal direction L, wherein fastening passages 510 are provided in the mounting areas 502. The mounting areas 502 are arranged such that they each have at least three fastening passages 510. Between the mounting areas 502, in particular when viewed in the longitudinal direction L, the bending stiffness of the end plate 500 is variable, wherein the bending stiffness decreases toward the mounting areas 502. The variable bending stiffness can be achieved here by reinforcing ribs 520 that extend parallel to the longitudinal direction L.

[0049] Reference numerals list

[0050] 1 Fuel Cell

[0051] 9 Fastening mechanism or connecting mechanism

[0052] 210 Bipolar Plate

[0053] 240 Pass-through

[0054] 242 Install the feedthrough

[0055] 244 Flow through

[0056] 250 Flow Cell

[0057] 252 Flow Area

[0058] 300 Bipolar Plate System

[0059] 310 Sealing element

[0060] 500 End Plate

[0061] 502 Installation Area

[0062] 510 Fixed through-hole

[0063] 520 Reinforcement Rib

[0064] B Width direction

[0065] L Longitudinal direction

[0066] H Height direction

Claims

1. A bipolar plate (210) for a fuel cell (1), wherein the bipolar plate (210) extends in a longitudinal direction (L) and in a width direction (B), wherein the longitudinal direction (L) and the width direction (B) are in particular perpendicular to each other, The bipolar plate (210) has a plurality of through-holes (240). The through-hole (240) has an outer contour, The outer contour of the through-hole (240) is respectively formed by a mounting through-hole (242) and at least one flow through-hole (244), wherein the mounting through-portion (242) constitutes an arc-shaped portion of the outer contour of the through-portion (240), and The installation passage (242) is configured to accommodate a fastening mechanism (9).

2. The bipolar plate (210) according to claim 1, The arc-shaped portion of the installation aperture (242) forms at least 51%, preferably at least 65%, and particularly preferably at least 75% of a circle.

3. The bipolar plate (210) according to any one of the preceding claims, The arc-shaped portion of the installation aperture (242) forms a maximum of 98%, preferably a maximum of 90%, and particularly preferably a maximum of 80% of a circle.

4. The bipolar plate (210) according to any one of the preceding claims, The bipolar plate (210) has a flow groove (250), in particular in a flow region (252) of the bipolar plate (210). The flow channel (250) in particular ends and / or begins in the passage (240).

5. The bipolar plate (210) according to any one of the preceding claims, in particular claim 5, wherein the flow channel (250) is formed by straight and rectangular sections, and / or The flow channel (250) extends in a serpentine shape.

6. A bipolar plate system (300), comprising a bipolar plate (210) according to any one of the preceding claims and a sealing element (310), in particular a sealing ring, The sealing element (310) is abutted against the bipolar plate (210). The sealing element (310) at least partially follows the arc-shaped portion of the outer contour of the passage (240).

7. The bipolar plate system (300) according to claim 6, The sealing element (310) projects into the aperture (240) or into at least two apertures (240).

8. The bipolar plate system (300) according to any one of claims 6 to 7, The bipolar plate system (300) has a plurality of sealing elements (310). wherein the sealing element (310) at least partially follows the course of an outer contour of the passage (240), and / or Each aperture (240) is surrounded by the outer contour of the sealing element (310).

9. The bipolar plate system (300) according to any one of claims 6 to 8, wherein the sealing element (310) is in particular materially bonded and / or reversibly fastened to the bipolar plate (210), and / or The sealing element (310) is manufactured by a screen printing method or by on-site molding.

10. The bipolar plate system (300) according to any one of claims 6 to 9, The sealing element (310) is arranged on the bipolar plate (210) such that the sealing element (310) forms a self-closed contour on the bipolar plate (210). In this case, at least two flow passages (244), in particular different passages (240), and / or flow regions (252) of the bipolar plate (210) are preferably arranged within the closed contour.

11. Use of the bipolar plate (210) according to any one of claims 1 to 5 and / or the bipolar plate system (300) according to any one of claims 6 to 10 in a fuel cell (1) / for a fuel cell.

12. An end plate (500) for a fuel cell (1), wherein the end plate (500) extends in a longitudinal direction (L) and a width direction (B), The end plate (500) has two mounting areas (502) which are spaced apart from each other, in particular in the longitudinal direction (L). The bending stiffness of the end plate (500), in particular between the mounting areas (502), is variable and advantageously decreases towards the mounting areas (502).

13. The end plate (500) according to claim 12, The end plate (500) has an arc-shaped reinforcing rib (520). The arc-shaped reinforcement rib (520) extends in particular parallel to the longitudinal direction (L).

14. Use of the end plate (500) according to any one of claims 12 to 13 in a fuel cell (1) / for a fuel cell.

15. A fuel cell (1), comprising a bipolar plate (210) according to any one of claims 1 to 5 and / or a bipolar plate system (300) according to any one of claims 6 to 10 and / or an end plate (500) according to any one of claims 12 to 13.

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