Flow mechanism for providing a medium flow at an intake opening of a fuel cell stack - Patents.com

Abstract

The present invention relates to a flow mechanism (30) for supplying a medium flow (1) at an intake opening (42) of a fuel cell stack (40), the flow mechanism (30) comprising a flow distributor (10) for flow engineering connection with the intake opening (42) of the fuel cell stack (40), the flow distributor (10) having a main flow section (12) and a secondary flow section (14) branching off from the main flow section (12), the main flow section (12) being configured with a flow intake (11) for supplying the medium flow (1) to the main flow section (12), the flow mechanism (30) further comprising a flow insert (20) arranged in the main flow section (12) and flow engineeringly linked to the flow intake (11), the flow insert (20) having at least one flow notch (22, 24) for equally distributing the medium flow (1) to the intake opening (42) via the main flow section (12) and the secondary flow section (14).

Description

[Technical Field]

[0001] The present invention relates to a flow mechanism for supplying a medium flow at an intake opening of a fuel cell stack, the flow mechanism comprising a flow distributor for flow engineering connection with the intake opening of the fuel cell stack, the flow distributor having a main flow area and a secondary flow area branching off from the main flow area, the main flow area being configured with a flow intake for supplying a medium flow to the main flow area.The present invention also relates to a fuel cell system comprising a plurality of fuel cell stacks and such a flow mechanism. [Background technology]

[0002] The flow distributor mentioned at the outset for supplying the medium flow at the inlet opening of a fuel cell stack is known from the prior art and is shown diagrammatically by way of example in the cross-section of FIG.

[0003] The flow distributor 10 shown in Figure 1 has a main flow section 12 and a secondary flow section 14 branching off therefrom, which can be connected to intake openings of a fuel cell stack (not shown in Figure 1). As can also be seen in Figure 1, a flow intake 11 is provided on the underside 17 of the flow distributor 10 relative to the orientation shown, through which the medium stream 1 enters the flow distributor 10 for distribution to the fuel cell stack.

[0004] Due to hydraulic and heat losses, it is not possible to provide equal mass, temperature, and velocity of medium for medium stream 1 in all of the secondary flow zones 14 by passing medium stream 1 sequentially through each secondary flow zone 14 as it exits the primary flow zone 12. However, such equal provision is desirable to enable uniform operation of all fuel cell stacks.

[0005] Figure 2 shows a solution to this problem according to the prior art. Unlike in Figure 1, the main flow zone 12 does not have a constant cross section here, but rather a cross section that tapers along its main direction of extension. For this purpose, in this example, the long second side wall 18 of the main flow zone 12 is arranged obliquely.

[0006] Although this allows for a more equal distribution of the medium flow feed to the secondary flow zone 14 in terms of mass and velocity, an even more equal distribution is desirable.

[0007] 1, the temperature of the medium in the medium flow 1 is greater in the secondary flow zones 14 that are further away from the flow intake 11, i.e., by several degrees, which can already have a significant effect on the chemical reactions. This means that the fuel cell stacks are not all equally supplied with the flow parameters of the medium flow 1 and are therefore increasingly subjected to different loads over their lifetime, which leads to higher power losses and aging and, in part, to an inability to operate as desired. Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to at least partially eliminate the above-mentioned disadvantages, and in particular to provide as equal a distribution of the medium flow as possible to the individual fuel cell stacks in a cost-effective and simple manner. [Means for solving the problem]

[0009] The above-mentioned problem is solved by a flow mechanism having the features of claim 1 and a fuel cell system having the features of claim 19. Further features and details of the invention will become apparent from the dependent claims, the detailed description and the drawings, whereby features and details described in the context of the flow mechanism according to the invention naturally also apply in the context of the fuel cell system according to the invention and vice versa, so that cross-reference is always made or can be made to the disclosure of the individual inventive aspects.

[0010] According to the present invention, a flow mechanism for supplying a medium flow at an intake opening of a fuel cell stack is provided, the flow mechanism having a flow distributor for flow engineering connection with the intake opening of the fuel cell stack, the flow distributor having a main flow area and a secondary flow area branching off from the main flow area, the main flow area being configured with a flow intake for supplying the medium flow to the main flow area, in particular to a flow insert arranged therein, and further having a flow insert arranged in the main flow area and flow engineeringly linked to the flow intake, the flow insert having at least one flow cutout for equally distributing the medium flow to the intake opening via the main flow area and the secondary flow area.

[0011] The present invention thus solves this problem by utilizing a specially designed flow insert in the main flow section of the flow system. The flow insert is configured with at least one flow notch for supplying an evenly distributed medium flow to the secondary flow section and, via this, to the intake opening of the fuel cell stack. The even distribution of the medium flow is provided via the at least one flow notch, since the medium does not enter the main flow section at only one point, i.e., at the flow intake, as in the prior art, but can instead exit via at least one further flow notch within the main flow section, which can be positioned anywhere along the flow insert. The guidance of the medium flow within the flow insert prevents the medium flow from flowing unevenly within the main flow section into the secondary flow section. The application of the flow mechanism according to the invention thus makes it possible to distribute the medium flow entering the flow distributor through one inlet opening (or optionally through several inlet openings, as will be explained in more detail below) to the secondary flow zones and thus to the inlet openings of the fuel cell stack more evenly, in particular with respect to the mass, temperature, and / or velocity of the medium flow. The term "equal distribution" used in this context is not necessarily understood to mean a mathematically perfect equal distribution, since this is not practically achievable. Rather, it means that an attempt is made to achieve the maximum or best equal distribution of the medium flow with respect to the flow parameters.

[0012] The individual fuel cell stacks may then be combined into a fuel cell system, which may include other peripherals and devices for operating the individual fuel cell stacks, such as valves, pumps, recirculation fans, etc.

[0013] Furthermore, the flow insert and the flow distributor may alternatively be separate, in particular integral, components, or may be an integrated flow mechanism. The first embodiment thus offers the advantage of easy retrofitting to existing flow distributors, since the flow distributor is equipped with a flow insert that can be attached to the main flow section. The second embodiment offers the advantage of easy manufacturing, for example, by using 3D printing. The flow distributor itself, including the main and secondary flow sections, may also be manufactured in one piece or from multiple parts.

[0014] It may be preferable for at least one of the at least one flow cutouts to be an intermediate flow cutout configured between the first and second ends of the flow insert. These ends may, in particular, be longitudinal ends of the flow insert. These ends may coincide with or be located on the ends of the main flow section or on a side wall, such as the upper or lower face. Arranging one or more flow cutouts as an intermediate flow cutout between these ends allows for uniform distribution of the medium flow in the flow height of the flow insert or along the flow or main direction of extension of the flow insert, in a fuel cell stack in which the inlet openings are located between the two ends. This is particularly preferable when more than two fuel cell stacks are used, i.e., for example, three, four, five, six, or more fuel cell stacks. The number of secondary flow sections then corresponds, in particular, to the number of fuel cell stacks, so that each fuel cell stack with an inlet opening can be assigned to one secondary flow section via a flow engineering connection.

[0015] In this case, it may be preferable for the flow insert to have several intermediate flow notches spaced apart from one another along the main direction of extension of the flow insert. Providing several intermediate flow notches, for example two, three, four or more intermediate flow notches, particularly improves the temperature equidistribution of the medium flow to the intake openings of the fuel cell stack. Due to the mutual spacing, which may be particularly even, the medium flow can be subdivided in the flow insert by the intermediate flow notches. Mutual influence of the individual partial medium flows emerging from the intermediate flow notches is largely avoided or minimized, so that they can be supplied to the individual sub-flow zones without being affected.

[0016] It may be preferable for each intermediate flow notch to be located at the flow height of a respective secondary flow zone. Flow height here is understood to mean the height measured in the direction of flow of the medium stream in the flow insert, i.e. along its main direction of extension, and therefore along and beside the respective secondary flow zone. In other words, each intermediate flow notch is opposite a secondary flow zone, so that the respective partial media streams of the medium stream can flow from the intermediate flow notch into the respective secondary flow zone in the correct order.

[0017] It may be preferable to configure at least one of the at least one intermediate flow notch on the side of the flow insert facing away from the secondary flow zone, in particular the secondary flow zone opening of the secondary flow zone. This allows for a particularly radial circumferential flow of the flow insert behind the secondary flow zone in the direction of the secondary flow zone. The medium flow guided in the flow insert then exits the intermediate flow notch as a partial medium flow toward the side wall of the main flow zone (referred to here as the second direction), where it collides and can be redirected in the opposite direction around the flow insert toward the secondary flow zone, in particular at the same flow height. In this way, partial medium flows separated from each medium flow can be provided in a favorable manner, in particular for multiple secondary flow zones and thus the fuel stack, which are each very strongly evenly distributed in terms of flow parameters, in particular mass, temperature, and velocity. This has the advantage of reducing flow impacts of the medium flow and providing particularly good alignment of the medium flow toward the secondary flow zone. In this way, all secondary flow zones can be provided with inlet faces as similar as possible and with interactions with locally similar areas of the outer housing, so that each secondary flow zone bears equal heat losses.

[0018] Additionally or alternatively, it may be preferable to arrange a flow guide element in at least one of the at least one intermediate flow notch for guiding the medium flow out of the at least one intermediate flow notch, through the main flow zone, and into one of the secondary flow zones. The flow guide element may optionally be straight, inclined (with respect to the normal or the main extension axis of the flow insert), and / or curved (especially away from the secondary flow zone). Furthermore, the flow guide element may be arranged on the side of the flow insert facing away from the above-mentioned, or alternatively, on the side of the flow insert facing towards the secondary flow zone. Naturally, positions in between are also possible. The flow guide element allows for controlled flow guidance to prevent undesired swirling and mixing of the partial medium streams exiting the flow notch.

[0019] In this case, it may be preferable for at least one flow guide element to be configured to generate a flow vortex of the medium flow around at least one portion of the flow insert, leading into one of the secondary flow zones. The length and swirl of the flow vortex can be adjusted, on the one hand, through the position of the flow guide element and, on the other hand, through its inclined and / or curved shape in the partial region as described above. The impact of the medium flow or partial medium flow exiting the flow insert is redirected, thereby providing a desired, controlled flow vortex around the flow insert between the (second) side wall of the main flow zone and the flow insert, further improving the equal distribution of the medium flow to the fuel cell stack. Unlike the embodiment described above, in which the partial medium flow exits on the opposite side of the flow insert through the intermediate flow cutout, here the partial medium flow is not split at the (second) side wall of the main flow zone. This allows for an even distribution of the medium flow while simultaneously ensuring good alignment of the medium flow with the secondary flow zones.

[0020] It may be preferable for at least one flow guide to extend between the flow insert and the second side wall of the main flow section of the flow distributor. In particular, the flow guide may be flow-tight toward one side, whereby the flow is redirected toward one side or only allowed toward one side. The flow guide may, for example, be an integral component of the flow insert and / or the flow distributor, or may be attached to one or both of them. The second side wall of the main flow section is, in particular, a wall or surface that circumscribes the flow insert. The first and third side walls of the main flow section may be located at the ends of the main flow section, and may form the upper or lower surface of the main flow section.

[0021] Additionally or alternatively, it may be preferable for at least one of the at least one intermediate flow notch to be configured on the flow insert side facing the secondary flow zone. Such an intermediate flow notch may be provided as an alternative or in addition to an intermediate flow notch on the flow insert side facing the opposite direction. In this way, it is possible to selectively create a direct inflow into the secondary flow zone (without a flow around the flow insert) or to supply a partial medium flow to the secondary flow zone from both flow insert sides.

[0022] Furthermore, it may be preferable for at least one intermediate flow recess to be configured as a slit in the flow insert. This slit can have an elongated shape, for example rectangular or oval. The slit has a greater extension in the longitudinal direction than in the transverse direction. With respect to its length, the slit can be configured transversely, in particular perpendicularly, to the main extension direction of the flow insert. The slit can be particularly easily manufactured in the flow insert and can have a limited flow cross section, so that it does not allow the entire medium flow in the flow insert to flow out, but only a controlled, limited amount.

[0023] The second end of the flow insert, remote from the flow intake, may be arranged in the first side wall of the flow distributor. Alternatively, and preferably, one of the at least one flow cutout may be an end cutout configured in the second end of the flow insert, remote from the flow intake. In this case, the second end is not arranged in the first side wall of the flow distributor, i.e., in a sealed manner, but is arranged in an open manner by the end cutout. In this case, the end cutout occupies the entire or almost the entire cross section of the flow insert, which is completely open at the second end. This is a relatively simple option for easily and evenly distributing the medium flow from the flow insert to the upper, or in other words, last, fuel cell stack in the flow direction of the medium flow, without the medium flow suffering losses in terms of temperature, mass, and / or velocity upon entering the first fuel cell stack. The medium flow exiting the end flow notch is bounced off the first side wall and thus flows into the upper or last secondary flow zone. As mentioned above, the first side wall may then be the upper surface of the main flow zone, which may in particular face the lower surface of the main flow zone at or near the flow intake.

[0024] It may also be preferable for the flow distributor to have at least one further intake opening for supplying the medium flow past the flow insert to the main flow zone, and / or for the intake opening to be configured so that the medium flow can be supplied past the flow insert to the main flow zone. In the latter embodiment, the intake opening can be correspondingly large in size and / or positioned to allow the medium flow to enter the main flow zone between the flow insert and the second side wall in addition to entering the flow insert. This is particularly preferable in connection with the end flow cutouts, since then the lower or first secondary flow zone can also be well supplied to ensure equal distribution of the medium flow to the fuel cell stack.

[0025] It may be preferable in some cases for the intake opening to be configured in the intake zone facing away from the main flow zone. This is particularly advantageous when there is limited design space in the main direction of extension of the main flow zone. In this case too, the intake opening and thus the intake zone may be present in the first side wall mentioned above, from which the main flow zone can extend along the main direction of extension in terms of its length and / or the intended medium flow.

[0026] It may then be advantageous to provide at least one further intake zone facing away from the main flow zone, with an intake opening, in the main flow zone at a distance from the other intake zones, so that further medium flows can be supplied at other locations, in particular at higher flow heights, thereby enabling an even better distribution of the medium flows.

[0027] Furthermore, it may be preferable to arrange at least two flow inserts next to each other in the flow distributor. These flow inserts can be supplied with the medium flow from a common flow intake or from individual flow intakes. In this way, larger medium flows can be easily generated. This has the advantage that the main flow zone and, if necessary, the secondary flow zones can be configured with larger widths.

[0028] It may be preferable for the flow insert and / or the main flow section to be a pipe, which is relatively uncomplicated and particularly cost-effective, with various pipe cross sections being possible, such as round, square, oval, heart-shaped, and mixtures thereof.

[0029] In particular, the flow insert is spaced apart from the main flow zone, very particularly on all sides or radially. In particular, it may be preferable for the flow distributor to be arranged concentrically, in particular coaxially, with respect to the main flow zone. In this way, a substantially uniform spacing can be achieved between the main flow zone, in particular its (second) side wall, and the flow insert, through which the medium flow, in particular the generated partial medium flow, can flow to reach the secondary flow zone.

[0030] Finally, it may be preferable for the sub-flow zone openings of the sub-flow zones to be different sizes. The sub-flow zone openings, or in other words the intakes of the sub-flow zones, are used for the inflow of the medium stream. Their different sizes can be achieved, for example, by corresponding throttle elements on them and / or in the sub-flow zones. Different sizing of the sub-flow zone openings of this kind, particularly with regard to their diameter, can also further optimize the equal distribution. For example, if a larger medium stream enters the first sub-flow zone in the flow direction of the medium stream than the others, these sub-flow zone openings can be resized to achieve a more equal distribution than the sub-flow zones located further back in the flow direction. This is because the medium stream arriving at the bottom must pass through a smaller opening cross-section, which limits the flow rate. This can also be pursued with the aim of influencing the equal distribution of the mixed temperature at the intake to the sub-flow zone.

[0031] The present invention also relates to a fuel cell system having a plurality of fuel cell stacks and a flow mechanism according to the present invention, in which one intake opening of each fuel cell stack is fluidically connected to a respective sub-flow zone of the flow mechanism.

[0032] The fuel cell system according to the invention thereby offers the same advantages as those detailed in connection with the flow mechanism according to the invention.

[0033] In this case, the intake openings of the fuel cell stack may preferably lead to the air side or the fuel side of the fuel cell stack, and accordingly the medium flow is preferably an air flow or a fuel flow, for example a hydrogen flow.

[0034] Of course, two or more flow mechanisms according to the present invention can be used in a fuel cell system according to the present invention. The flow mechanisms can be used for different media and therefore for different intake openings of the fuel cell stack. For example, one flow mechanism can be used for the air side of the fuel cell stack and another for the fuel side of the fuel cell stack. Alternatively, within a single equipment / media system, a division into subsystems each with a series of fuel cell stacks, with a central media supply, can be preferable for multiple applications.

[0035] Other advantages, features and specific features of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention, which are given with reference to the accompanying drawings. [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a vertical cross-sectional view of a flow distributor according to a first embodiment of the prior art; [Figure 2] FIG. 2 is a vertical cross-sectional view of a flow distributor according to a second embodiment of the prior art. [Figure 3a] 1 is a vertical cross-sectional view showing a flow mechanism according to a first embodiment of the present invention; [Figure 3b] FIG. 3b is a horizontal cross-section showing the flow mechanism of FIG. 3a. [Figure 4a] FIG. 2 is a vertical cross-sectional view showing a flow mechanism according to a second embodiment of the present invention. [Figure 4b] FIG. 4b is a horizontal cross-section showing the flow mechanism of FIG. 4a. [Figure 5a] FIG. 10 is a vertical cross-sectional view showing a flow mechanism according to a third embodiment of the present invention. [Figure 5b] FIG. 5b is a horizontal cross-sectional view of the flow mechanism of FIG. 5a. [Figure 6a] FIG. 10 is a vertical cross-sectional view showing a fuel cell system having a flow mechanism according to a fourth embodiment of the present invention. [Figure 6b] FIG. 6b is a horizontal cross-section showing the flow mechanism of FIG. 6a. [Figure 7] FIG. 10 is a horizontal cross-sectional view showing a flow mechanism according to a fifth embodiment of the present invention. [Figure 8] FIG. 10 is a horizontal cross-sectional view showing a flow mechanism according to a sixth embodiment of the present invention. [Figure 9] FIG. 10 is a horizontal cross-sectional view showing a flow mechanism according to a seventh embodiment of the invention. [Figure 10] FIG. 10 is a vertical cross-sectional view showing a flow mechanism according to an eighth embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] Identical or functionally identical components are designated by the same reference numerals in each of FIGS.

[0038] Of course, the designations horizontal and vertical should not be understood as limiting, but have merely been chosen to clarify the spatial allocation of the figures relative to one another.

[0039] 3a shows an embodiment of a flow mechanism 30 according to the invention, which is improved with respect to the flow insert 20 and other measures with respect to the flow distributor 10 known from the prior art, as will be explained in more detail below. Here, the flow mechanism 30 is shown in a vertical cross section along the main direction of extension, in particular along the longitudinal extension, of the flow insert 20, which also coincides with the flow direction of the supplied medium stream 1.

[0040] The flow insert 20 is configured within the main flow section 12 of the flow distributor 10, which here defines a main flow passageway. Here, the flow insert 20 is spaced apart from the second sidewall 18 of the main flow section 12, which surrounds the flow insert 20 as an outer wall of the main flow section 12. In particular, the flow insert 20 is concentrically disposed within the main flow section 12.

[0041] The main flow section 12, the secondary flow section 14, and / or the flow insert 20 may be configured in a tubular shape, as shown in Figure 3b, a cross section taken horizontally relative to Figure 3a through the main flow section 12 and the flow insert 20 for the main flow section 12. Purely by way of example, the tubular cross sections of the main flow section 12 and the flow insert 20 are shown here as circular, although alternatively, one or both of them may be rectangular, oval, or heart-shaped (Figure 7), for example.

[0042] As shown in Figure 3a, the main flow section 12 includes a flow intake 11 at a corresponding lower surface 17 of the main flow section 12 (the lower surface 17 is in particular the third side wall of the flow distributor 10), which is flow-engineered, or in other words fluidically, connected to the flow insert 20 therein. In this way, a medium stream 1, which may comprise, for example, air or a fuel for a fuel cell stack 40 (see Figure 6a), can be introduced into the flow insert 20 and flow therein along the main flow section 12.

[0043] At the end of the flow insert 20, referred to here as the second end 23, a flow notch is present in the form of an end flow notch 24. For this reason, the flow insert 20 is open at the second end 23. The second end 23 faces the first end 21, at which the flow intake 11 is located. Through the end flow notch 24, the medium stream 1 leaves the flow insert 20 at the second end 23 and, thus, bypasses the flow insert 20 to reach the rear, or last, secondary flow zone 14 and its secondary flow zone opening 15, as seen in the flow direction or main direction of extension of the main flow zone 12. The exiting medium stream 1 then impinges on the first side wall 13 (in particular on the upper surface) and is redirected transversely, in particular perpendicularly, to the second side wall 18 and to the flow intake 11 into the rear secondary flow zone 14, as shown by the corresponding arrows representing the partial flow direction or partial medium flow of the medium stream 1.

[0044] In addition to the above-mentioned flow intakes 11, two second flow intakes 11 are configured on the underside 17 of the main flow section 12 alongside the first end 21 of the flow insert 20, or alternatively, one particularly large flow intake 11 is provided that is larger than the cross section of the flow insert 20 at the first end 21. Through both flow intakes 11, or through the particularly large-sized flow intake 11, the medium stream 1 is likewise introduced into the main flow section 12, but without detouring via the flow insert 20. The medium stream 1 introduced in this way easily reaches the front or first secondary flow section 14 and its secondary flow section opening 15, as viewed in the flow direction or main extension direction of the main flow section 12.

[0045] The above-described combination of the medium flow 1 in the first sub-flow zone 14, which does not pass through the flow insert 20, and the last sub-flow zone 14, which does pass through the flow insert 20, results in a good equal distribution of the medium flow 1 in terms of mass, temperature, and velocity in all sub-flow zones 14. The last sub-flow zone 14 then receives a sufficient supply of insulated high-temperature medium from the correspondingly dimensioned flow insert 20.

[0046] As shown in Figure 3a, the sub-flow zone openings 15 of the sub-flow zone 14 are also configured with different sizes, i.e., the sub-flow zone openings 15 here, by way of example, gradually increase in size in the flow direction. This is achieved by appropriately dimensioned throttle elements in the sub-flow zone 14, as shown in Figure 3a or, by way of example, in Figures 4a, 5a, and 6a. Additionally or alternatively, this can also be achieved by differently sized cross sections of the sub-flow zones 14. This likewise allows for a more uniform distribution of the medium flow 1 to the fuel cell stack 40.

[0047] FIG. 4a shows an alternative embodiment of the flow mechanism 30 to that of FIG. 3a, in which the end flow notches 24 are not provided. Instead, the flow insert 20 extends entirely into the main flow section 12. Furthermore, the flow insert 20 is provided with intermediate flow notches 22, which are configured on the flow insert side 26 of the flow insert 20, which faces away from the secondary flow section 14, for example. Furthermore, the intermediate flow notches 22 are configured as slits, for example, with a slit length transverse to the main extension direction of the flow insert 20. The individual intermediate flow notches 22 are spaced apart from one another in the longitudinal extension direction of the flow insert 20 and are each located at the flow height of the secondary flow section 14. The size or number of the intermediate flow notches 22 is preferably configured differently depending on the distribution path length.

[0048] 4b shows in a horizontal cross section through the flow device 30 (at the flow height of one of the sub-flow zones 24), here at the flow height of each intermediate flow notch 22, a partial medium stream of the medium stream 1 is guided through the flow insert 20 towards the second side wall 18, collides there, and flows around the flow insert 20 towards the respective sub-flow zone 14 and thus to the respective fuel cell stack 40. This occurs at each flow height of the sub-flow zone 14, which allows, as a whole, an evenly distributed flow of the medium 1 to the individual fuel cell stacks 40 with a small inclination angle, as already explained above, since the medium stream is equalized when flowing around the flow insert 20.

[0049] Figure 5a shows yet another alternative embodiment of flow feature 30, illustrating a combination of the embodiment of Figure 3a and a modification of the embodiment of Figure 4a. Figure 5b shows a horizontal cross-sectional view, here above end flow cutout 24 of flow insert 20. Unlike what is shown in Figure 4a, here middle flow cutout 22 is configured on flow insert side 25 of flow insert 20 facing toward secondary flow zone 14, as shown in Figure 5b. A combination of middle flow cutout 14 on flow insert side 25 facing toward secondary flow zone 14 and flow insert side 26 facing away from secondary flow zone 14 is also possible, as shown in Figure 9.

[0050] 6a shows a fuel cell system 50 having a plurality of fuel cell stacks 40, each having an inlet opening 42 for the medium flow 1. The fuel cell stacks 40 may be, for example, polymer electrolyte membrane fuel cell stacks or solid oxide fuel cell stacks. The inlet openings 42 are fluidically connected to the secondary flow zones 14 of a flow system 30 according to yet another embodiment. FIG. 6b shows a horizontal cross-section of the flow system 30 of FIG. 6a at the flow height of one of the secondary flow zones 14.

[0051] As a modification from the above embodiments, here each intermediate flow notch 22 is provided with a flow guide member 28 for guiding the medium flow 1 out of the respective intermediate flow notch 22, through the main flow zone 12 and into one of the secondary flow zones 14.

[0052] The flow guide elements 28 here extend between the flow insert 20 and the main flow zone 12. The arrangement of the flow guide elements 28 shown in FIG. 6b on the flow insert side 25 facing the secondary flow zone 14 serves to prevent the partial medium streams from the intermediate flow cutouts 22 from flowing directly into the respective secondary flow zone 14. Instead, the partial streams of the medium stream 1 have to bypass the flow insert 20, whereby the respective flow guide elements 28 create a flow vortex around the flow insert 20 which, after flowing around the flow insert 20 and, in particular, after circling around, leads to the respective secondary flow zone 14.

[0053] 6a further shows an embodiment of the flow arrangement 30 in which the medium stream 1 does not enter the main flow zone 12 through the intake opening 11 in the lower surface 17 thereof, but instead through an intake zone 16 which branches off laterally from the main flow zone 12 and which may be fabricated, for example, as a pipe. Furthermore, an optional further intake zone 16 is shown at approximately the middle flow height of the main flow zone 12, through which the medium stream 1 can be additionally fed.

[0054] Furthermore, Figure 6b shows an alternative embodiment in which the almost complete circumferential flow of the flow insert 20 is performed by the medium flow 1 in a clockwise and eccentrically convergent manner, so that the resulting inflow vortex is formed and further utilized throughout the main flow zone 12, thereby enabling a particularly uniform inflow into the corresponding secondary flow zone openings 15 due to the longer flow path.

[0055] FIG. 7 shows a modification of the embodiment of the flow feature 30 of FIG. 4b in which the flow insert 20 has a heart-shaped cross-section instead of a circular cross-section.

[0056] 8 shows in horizontal cross section an embodiment of a flow mechanism 30 having two side-by-side flow inserts 20 in the main flow zone 12, the flow inserts 20 being constructed, by way of example, based on the embodiment shown in FIGS. 4a and 4b. This embodiment allows for a smaller design space for the main flow zone 12 and a greater expansion of the flow in the direction of the secondary flow zone 14, when space considerations necessitate a wide, but flat, rectangular cross section at the secondary flow zone opening 15.

[0057] 9 shows in horizontal cross section yet another embodiment of a flow mechanism 30 having a flow insert 20 with a rectangular cross section. Here, the intermediate flow cutouts 22 are arranged not only on the flow insert side 25 facing towards the secondary flow zone 14, but also on the flow insert side 26 facing away from the secondary flow zone 14. Furthermore, here, two intake openings 11 are provided for the flow insert 20, as can be seen by reference to the partial medium flows indicated by the arrows inside the flow insert 20.

[0058] Finally, Figure 10 shows yet another embodiment of a flow mechanism 30 according to the present invention, which, unlike the embodiment of Figures 3a and 3b, illustratively only has two sub-flow zones 14, which are also illustratively located at each end of the flow mechanism 30. In addition, the flow insert 20 of Figure 10 is shortened compared to the flow insert 20 of Figures 3a and 3b, thereby creating a wider spacing between the first side wall 13 and the flow insert 20.

[0059] The above description of the various embodiments describes the present invention by way of example only. (Other possible items) (Item 1) A flow mechanism (30) for supplying a medium flow (1) at an inlet opening (42) of a fuel cell stack (40), the flow mechanism (30) comprising a flow distributor (10) for flow engineering connection with the inlet opening (42) of the fuel cell stack (40), the flow distributor having a main flow area (12) and a secondary flow area (14) branching off from the main flow area (12), the main flow area (12) including a flow channel (14) for supplying the medium flow (1) to the main flow area (12). a flow mechanism (30) configured with a flow intake (11) for supplying a medium flow (1) to the intake opening (42) via the main flow section (12) and the secondary flow section (14), the flow mechanism (30) further comprising a flow insert (20) arranged in the main flow section (12) and fluidically linked to the flow intake (11), the flow insert (20) having at least one flow notch (22, 24) for equally distributing the medium flow (1) to the intake opening (42) via the main flow section (12) and the secondary flow section (14). (Item 2) Item 1, wherein at least one of the at least one flow notch (22, 24) is an intermediate flow notch (22) configured between the first end (21) and the second end (23) of the flow insert (20). (Item 3) 3. The flow mechanism (30) according to item 2, wherein the flow insert (20) has a plurality of the intermediate flow notches (22) spaced apart from one another along the main extension direction of the flow insert (20). (Item 4) 4. The flow mechanism (30) according to item 3, wherein each one of the intermediate flow notches (22) is located at a flow height of each one of the sub-flow zones (14). (Item 5) 5. The flow mechanism (30) according to any one of claims 2 to 4, wherein at least one of the at least one intermediate flow notch (22) is configured on a flow insert side (26) of the flow insert (20) facing away from the secondary flow zone (14). (Item 6) 6. The flow mechanism (30) according to any one of items 2 to 5, wherein a flow guiding element (28) is arranged in at least one of the at least one intermediate flow notch (22) for guiding the medium flow (1) out of the at least one intermediate flow notch (22), through the main flow zone (12), and into one of the secondary flow zones (14). (Item 7) 7. The flow mechanism (30) according to claim 6, wherein at least one of the flow guide members (28) is configured to generate a flow vortex of the medium flow (1) around at least one portion of the flow insert (20) and leading into one of the secondary flow zones (14). (Item 8) 8. The flow mechanism (30) according to item 6 or 7, wherein at least one of the flow guide members (28) extends between the flow insert (20) and a second side wall (18) of the main flow section (12) of the flow distributor (10). (Item 9) 9. The flow mechanism (30) according to any one of items 2 to 8, wherein at least one of the at least one intermediate flow notch (22) is configured on a flow insert side (25) of the flow insert (20) facing towards the secondary flow zone (14). (Item 10) 10. The flow mechanism (30) according to any one of items 2 to 9, wherein at least one of the intermediate flow notches (22) is configured as a slit in the flow insert (20). (Item 11) 11. A flow mechanism (30) according to any one of items 1 to 10, wherein one of the at least one flow notch (22, 24) is an end flow notch (24) configured at a second end (23) of the flow insert (20) that is remote from the flow intake portion (11). (Item 12) 12. The flow mechanism (30) according to any one of claims 1 to 11, wherein the flow distributor (10) has at least one further intake opening (11) for supplying the medium flow (1) to the main flow zone (12) by passing the flow insert (20), and / or the intake opening (11) is configured so that the medium flow (1) can be supplied to the main flow zone (12) by passing the flow insert (20). (Item 13) 13. The flow mechanism (30) according to any one of items 1 to 12, wherein the intake opening (11) is configured in an intake section (16) facing away from the main flow section (12). (Item 14) Item 14. The flow mechanism (30) according to item 13, wherein at least one other intake zone (16) facing away from the main flow zone (12) and having the intake opening (11) is configured in the main flow zone (12) at a distance from the other intake zones (16). (Item 15) 15. The flow mechanism (30) according to any one of items 1 to 14, wherein at least two flow inserts (20) are arranged side by side in the flow distributor (10). (Item 16) 16. The flow mechanism (30) according to any one of the preceding items, wherein the flow insert (20) and / or the main flow section (12) is a pipe. (Item 17) 17. The flow mechanism (30) according to any one of items 1 to 16, wherein the flow insert (20) is arranged concentrically with respect to the main flow section (12). (Item 18) 18. The flow mechanism (30) according to any one of items 1 to 17, wherein the sub-flow zone openings (15) of the sub-flow zones (14) are of different sizes. (Item 19) A fuel cell system (50) having a plurality of fuel cell stacks (40) and the flow mechanism (30) described in any one of items 1 to 18, wherein each intake opening (42) of each of the fuel cell stacks (40) is fluidically connected to a respective sub-flow zone (14) of the flow distributor (10) of the flow mechanism (30). (Item 20) 20. The fuel cell system (50) of claim 19, wherein the intake opening (42) of the fuel cell stack (40) leads to an air side or a fuel side of the fuel cell stack (40). [Explanation of symbols]

[0060] 1 Media flow 10 Flow distributor 11 Flow intake section 12 Main flow area 13 First side wall 14 Sub-flow area 15 Secondary flow area opening 16 Intake Area 17 Bottom side 18 Second Side Wall 20 Flow Insert 21 first end 22 Intermediate flow notch 23 Second end 24 End / flow notch 25 flow insert side facing the secondary flow zone 14 26 flow insert side facing away from secondary flow zone 14 28 Flow guide member 30 Flow mechanism 40 Fuel Cell Stack 42 Intake opening 50 Fuel Cell System

Claims

1. 1. A flow mechanism for supplying a medium flow at an intake opening of a fuel cell stack, the flow mechanism comprising a flow distributor having a main flow area and a secondary flow area branching off from the main flow area for flow engineering connection with the intake opening of the fuel cell stack, the main flow area being configured with a flow intake for supplying the medium flow to the main flow area, the flow mechanism further comprising a flow insert disposed in the main flow area and flow engineeringly linked to the flow intake, the flow insert having at least one flow cutout for equally distributing the medium flow through the main flow area and the secondary flow area to the intake opening.

2. The flow mechanism of claim 1 , wherein at least one of the at least one flow notch is an intermediate flow notch configured between a first end and a second end of the flow insert.

3. The flow mechanism of claim 2 , wherein the flow insert has a plurality of the intermediate flow notches spaced apart from one another along a primary extension direction of the flow insert.

4. The flow mechanism of claim 3 , wherein a respective one of the intermediate flow notches is located at a flow height of a respective one of the sub-flow zones.

5. The flow mechanism of claim 2 , wherein at least one of the at least one intermediate flow notch is configured on a flow insert side of the flow insert facing away from the secondary flow zone.

6. 3. The flow mechanism according to claim 2, wherein a flow guiding member is disposed in at least one of the at least one intermediate flow notch to guide the medium flow out of the at least one intermediate flow notch through the main flow zone and into one of the secondary flow zones.

7. The flow mechanism of claim 6 , wherein at least one of the flow guide members is configured to generate a flow vortex of the media flow around at least one portion of the flow insert and into one of the secondary flow zones.

8. The flow mechanism of claim 6 , wherein at least one of the flow guide members extends between the flow insert and a second sidewall of the main flow section of the flow distributor.

9. The flow mechanism of claim 2 , wherein at least one of the at least one intermediate flow notch is configured on a flow insert side of the flow insert facing the secondary flow zone.

10. The flow mechanism of claim 2 , wherein at least one of the intermediate flow notches is configured as a slit in the flow insert.

11. The flow mechanism of claim 1 , wherein one of the at least one flow notch is an end flow notch configured at a second end of the flow insert remote from the flow intake.

12. 2. The flow mechanism of claim 1, wherein the flow distributor has at least one other intake opening for supplying a medium flow past the flow insert to the main flow section, and / or the intake opening is configured to allow a medium flow to be supplied past the flow insert to the main flow section.

13. The flow mechanism of claim 1 , wherein the intake opening is configured in an intake area facing away from the main flow area.

14. The flow mechanism of claim 13 , wherein at least one other intake zone facing away from the main flow zone and having the intake opening is configured in the main flow zone spaced apart from the other intake zones.

15. The flow mechanism of claim 1 , wherein at least two flow inserts are positioned side-by-side in the flow distributor.

16. The flow system of claim 1 , wherein the flow insert and / or the main flow section is a pipe.

17. The flow mechanism of claim 1 , wherein the flow insert is concentrically positioned relative to the main flow section.

18. The flow mechanism of claim 1 , wherein the sub-flow zone openings of the sub-flow zones are different sizes.

19. 20. A fuel cell system having a plurality of fuel cell stacks and a flow mechanism according to any one of claims 1 to 18, wherein each intake opening of each of the fuel cell stacks is fluidically connected to a respective sub-flow zone of the flow distributor of the flow mechanism.

20. 20. The fuel cell system of claim 19, wherein the intake opening of the fuel cell stack leads to an air side or a fuel side of the fuel cell stack.

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