fuel cells

Abstract

The fuel cell includes a base plate (11), a stack (20) held against the base plate (11), and a compression system. The compression system includes a movable support plate (30) held against the stack (20), a spring (50) held against the support plate (30), and a clamp (40) held against the spring (50). To ensure stability of the fuel cell over time, the fuel cell includes a first sliding connection (70) for slidingly guiding the support plate (30) relative to the base plate (11). The fuel cell also includes a draw plate (60) separated from the base plate (11), which includes anchors. These anchors attach the draw plate (60) to the base plate (11) and the clamp (40), thereby maintaining the stack (20) in a compressed state between the base plate (11) and the support plate (30) by the anchors under the action of the spring (50).

Description

[Technical Field]

[0001] The present invention relates to a fuel cell. [Background technology]

[0002] Patent Document 1 describes a fuel cell having a stack of electrochemical cells. The electrochemical cells are stacked between two terminal plates and maintained in a compressed state along the stacking direction. To maintain the stack in compression, the terminal plates are surrounded by a retention system comprising transverse members, Belleville springs, and rods. The transverse members are located on each side of the terminal plates and are interconnected by rods extending parallel to the stacking direction from one end of the stack to the other. At each end of the stack, the transverse members are held against the terminal plates under the action of these rods, with Belleville springs and pressure distribution plates interposed between the transverse members and the terminal plates on each side of the stack. A casing surrounds the assembly.

[0003] This known fuel cell in practice has the drawback that the compression state of the stack may lack precision and / or become unstable over time, in particular due to axial deformations of the stack caused in particular by thermal stresses, which may result in lateral stresses in the stack and compression retention system. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2020 / 144651 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to overcome the drawbacks of the prior art by proposing a novel fuel cell which is particularly stable over time. [Means for solving the problem]

[0006] The present invention relates to a fuel cell. The fuel cell includes a base plate, a stack including electrochemical cells stacked in a compression direction and held against the base plate in the compression direction, and a compression system. The compression system includes a support plate movable relative to the base plate parallel to the compression direction and held against the stack in the compression direction, a spring held against the support plate in the compression direction, and a clamp held against the spring in the compression direction. According to the present invention, the fuel cell includes a first sliding connection, by which the support plate is slidably guided relative to the base plate in the compression direction. According to the present invention, the compression system further includes draw plates separated from each other, each having an anchor, and the draw plate is attached to the base plate and the clamp by the anchor. Thus, the draw plates ensure that the stack is maintained in compression between the base plate and the support plate by the anchor in the compression direction under the action of the spring pressing against the clamp.

[0007] One idea underlying the present invention is that the use of a sliding connection to maintain the position of the support plate laterally ensures that the support plate remains perfectly aligned with the base plate in the compression direction, eliminating the possibility of imbalance in the distribution of compression forces applied to the stack by the clamps via springs. The draw plate, along with the anchors, absorbs most of the torsional stresses that may be applied to the stack and compression system, thus improving the stability of stack compression over time.

[0008] Preferably, the first sliding connection comprises a primary sliding part mounted to the support plate and a secondary sliding part mounted to the base plate, the primary sliding part and the secondary sliding part being received within each other so as to slide relative to each other in the compression direction, thus guiding the sliding of the support plate relative to the base plate.

[0009] Preferably, the fuel cell comprises a casing, the casing housing the stack, the compression system and the clamp and fixedly mounted to the base plate, and preferably the secondary slide is fixedly mounted to the casing, preferably at the level of the clamp or spring in the compression direction, and thereby fixedly mounted to the base plate.

[0010] Preferably, each draw plate includes a common tie and an individual tie, the common tie and the individual tie supporting anchors, and each individual tie is attached to the common tie and is positionally adjustable relative to the common tie in the compression direction to adjust the position of the anchor for attaching the draw plate to the base plate and the position of the anchor for attaching the draw plate to the clamp.

[0011] Preferably, each individual tie is connected to the common tie by a helical connection parallel to the direction of compression, so as to allow adjustment of the position of each individual tie relative to the common tie.

[0012] Preferably, each draw plate includes stringers parallel to the compression direction.

[0013] Preferably, each draw plate includes a crosspiece fixedly connected to the stringer to rigidly connect the stringers to one another, the crosspiece being located between the clamp and the base plate.

[0014] Preferably, for each draw plate, at least two stringers are separated by an inter-stringer distance that is greater than 50% of the width of the stack, the inter-stringer distance being measured perpendicular to the compression direction and the stack width being measured parallel to the inter-stringer distance.

[0015] Preferably, each stringer is axially aligned in the compression direction with one of the draw plate anchors, and preferably with two of the draw plate anchors, and is positioned between said two anchors.

[0016] Preferably, at least one of the anchors comprises at least one wing extending radially from the stringer and adapted to press against the base plate in a direction opposite to the compression direction, thereby attaching the draw plate to the base plate, the at least one wing being disposed in the plane of the plate through which the stringer extends.

[0017] Preferably, for each draw plate, the anchors include a primary anchor for attaching the draw plate to the base plate and a secondary anchor for attaching the draw plate to the clamp.

[0018] Preferably, the draw plate comprises a first draw plate and a second draw plate parallel to each other.

[0019] Preferably, the first draw plate and the second draw plate are disposed on either side of the stack in opposite directions relative to the stack.

[0020] Preferably, the fuel cell comprises a second sliding connection, and the clamp is slidably guided relative to the support plate in the compression direction by the second sliding connection.

[0021] Preferably, the clamp is made from separate parts that are independent of each other.

[0022] The present invention and further advantages thereof will become apparent from the following detailed description of an embodiment consistent with the principles of the invention, taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a longitudinal cross-sectional view of a fuel cell according to one embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view of the fuel cell of FIG. [Figure 3] 3 is a perspective view from another angle of a subassembly belonging to the fuel cell of FIGS. 1 and 2, including a base plate and a compression system; FIG. [Figure 4] FIG. 4 is a partial side view of the subassembly of FIG. 3. [Figure 5] FIG. 5 is a partial perspective view of the subassembly of FIGS. 3 and 4. DETAILED DESCRIPTION OF THE INVENTION

[0024] 1 and 2 show a fuel cell including a base plate 11, a stack 20, and a compression system. Preferably, the fuel cell includes a casing 10. The compression system includes a support plate 30, clamps 40, springs 50, and draw plates 60, of which there are only two. FIGS. 3 to 5 show the fuel cell without the casing 10 and stack 20.

[0025] A compression direction X10, a first lateral direction Y10, and a second lateral direction Z10 are set, and these three directions are perpendicular to each other and fixed relative to the base plate 11.

[0026] Preferably, the fuel cell is used in a vehicle, in particular in a car or other moving vehicle, such as a passenger car or truck, to ensure the power supply to one or more motors that ensure the propulsion of the vehicle.

[0027] The stack 20 is indicated by dashed lines in FIGS. 3 and 4. The stack 20 is a stack of electrochemical cells 21. These electrochemical cells 21 are shown schematically in FIG. 1 but are not individually shown for the sake of simplicity, as they may consist of, for example, 250 to 400 cells 21. Each electrochemical cell 21 comprises, for example, an anode and a cathode, which are separated by a polymer membrane that allows the passage of protons from the anode to the cathode. During use of the fuel cell, each anode of the stack 20 is supplied with a fuel, such as dihydrogen, and each cathode of the stack 20 is supplied with an oxidant, such as oxygen or air.

[0028] To form the stack 20, the electrochemical cells 21 are stacked, in other words, overlapped, according to a compression direction X10. Each cell 21 extends according to an individual plane that is perpendicular to the direction X10. Preferably, this compression direction X10 is approximately horizontal when the fuel cell is in operation, for example in a vehicle.

[0029] A central axis X20 that passes through the stack 20 and is parallel to the direction X10 is defined for the stack 20. Furthermore, the axis X20 passes through the base plate 11, the support plate 30, and the clamp 40.

[0030] The casing 10 surrounds and protects the stack 20, the compression system, and the base plate 11. In other words, the casing 10 houses these elements. The casing 10 includes a lateral wall 12 and a longitudinal wall 13. The lateral wall 12 is perpendicular to the direction X10. The axis X20 passes through the lateral wall 12. The longitudinal wall 13 is parallel to the direction X10. The longitudinal wall 13 is a circumferential wall surrounding the stack 20, i.e., has a tubular shape, and extends to the wall 13 in the direction X10 and beyond the clamp 40 in the direction opposite to the direction X10. The longitudinal wall 13 surrounds the axis X20. The wall 12 is fixedly attached to the wall 13 at one end of the wall 13 to close the casing 10. The stack 20 is disposed inside the casing 10, particularly inside the wall 13. Overall, walls 12 and 13 are arranged so that casing 10 has a generally parallelepiped shape.

[0031] Preferably, the lateral walls 12 receive the base plate 11 in a supporting manner according to the compression direction X10. The base plate 11 is oriented perpendicular to the direction X10 and is held flat against the wall 12. In this case, the base plate 11 is fixed to the wall 12, for example by means of screws. More generally, it is advantageous to configure the base plate 11 so that it is fixedly attached to the casing 10.

[0032] In this case, the base plate 11 serves as a fixed terminal plate for the stack 20 in that the stack 20 is supported flat against the base plate 11 in the compression direction X10. However, it is also possible for the stack 20 to be provided with a separate fixed terminal plate, and for the stack 20 to be in abutment against the base plate 11 via this fixed terminal plate.

[0033] Preferably, the base plate 11 is provided with openings through which connectors (not shown) can pass, which are provided for connection to fluid circulation pipes, so that the stack 20 can be supplied with fuel, oxidant and possibly cooling fluid, and can also be evacuated of reaction products, if any. Advantageously, corresponding openings are provided on the lateral walls 12.

[0034] The stack 20 is received between the support plate 30 and the base plate 11 and is compressed in the direction X10 between these two plates 11 and 30. In particular, the plate 30 applies a compressive force F30 directed in the direction X10 to the stack 20, which is held in abutment against the base plate 11. The support plate 30 is held in abutment against the stack 20 in the direction X10 on the opposite side of the base plate 11. The support plate 30 is oriented perpendicular to the direction X10 and is held flat in abutment against the stack 20.

[0035] Advantageously, the support plate 30 and base plate 11 are held flat against the stack 20, ensuring that the mechanical stress resulting from the force F30 is distributed across the end surface of the stack 20.

[0036] The support plate 30 is movable relative to the base plate 11 in a direction parallel to the compression direction, which allows the distance between the support plate 30 and the base plate 11 to change over time during use of the fuel cell, thereby adapting to dimensional changes in the stack 20 that may be caused by various factors, particularly heat.

[0037] The fuel cell comprises a sliding connection 70 for the support plate 30, called a sliding connection plate 70, formed inside the casing 10. The support plate 30 is slidably guided by the sliding connection plate 70 relative to the base plate 11 in the compression direction X10. In other words, the sliding connection plate 70 prevents the support plate 30 from pivoting as a whole relative to the base plate 11 and prevents the support plate 30 from displacing relative to the base plate 11 in the transverse directions relative to the direction X10, in particular in the directions Y10 and Z10. The sliding connection plate 70 therefore stabilizes the support plate 30 and the stack 20 not only during assembly of the fuel cell but also during use of the fuel cell. These arrangements therefore make it less likely that deformations of the stack 20, especially under the influence of heat and possible vibrations that may be generated by the stack 20, will affect the integrity of the fuel cell.

[0038] 1 and 2, the sliding connection plate 70 comprises a primary sliding plate 71 and a secondary sliding plate 72, which are distributed in pairs. In this example, two pairs of sliding plates 71 and 72 are provided. At least one pair of primary sliding plates 71 and secondary sliding plates 72 is provided. Each primary sliding plate 71 is preferably fixedly attached to the support plate 30. Each secondary sliding plate 72 is preferably fixedly attached to the base plate 11. For this reason, preferably, the secondary sliding plate 72 is fixedly attached to the casing 10, which is fixedly attached to the base plate 11. In each pair, the sliding plates 71 and 72 are received within each other and thereby slide relative to each other in the direction X10, thus guiding the sliding of the support plate 30 relative to the base plate 11. Advantageously, each pair of sliding plates 71 and 72 is arranged perpendicular to the direction X10 between the casing wall 13 and the clamp 40 and at the height of the clamp 40 in the direction X10.

[0039] In this example, for a given primary sliding plate 71, and possibly for each primary sliding plate 71, the primary sliding plate 71 is constituted by a rod parallel to the direction X10 and fixedly attached to the plate 30 by being mounted on the plate 30. As can be seen, for example, in Figure 1, the rod of a given primary sliding plate 71 has a threaded end that is received in a tapped hole in the plate 30 and a smooth end for guiding the sliding. For example, the rod can protrude from the plate 30 in a direction opposite to the direction X10 relative to the stack 20 and extend beyond the clamp 40.

[0040] In this example, each secondary sliding plate 72 is fixedly mounted to the base plate 11 by the casing 10 by having a sliding bore that is parallel to the direction X10 and fixedly mounted to the wall 13 of the casing 10. Preferably, all sliding bores are formed at the same height in the direction X10 and are distributed in a plane perpendicular to the direction X10. Preferably, for a given secondary sliding plate 72, and possibly for each secondary sliding plate 72, the sliding bore is formed through a respective lug 14 belonging to the casing 10. Each lug 14 is fixedly mounted directly to the wall 13 on the interior of the casing 10, for example approximately at the height of the clamp 40. It is also possible for a given secondary sliding plate 72, and possibly for each secondary sliding plate 72, to have a sliding sleeve 15 that forms a sliding bore and is fixedly received through the corresponding lug 14. Advantageously, the sliding sleeve 15 allows for more accurate sliding of the rod than would be possible with a sliding bore arranged directly through the lug 14, and / or allows for the use of a material for the sliding bore that is less susceptible to wear and / or is more suitable for sliding of the rod within the sliding bore in the direction X10.

[0041] A plurality of springs 50, here nine springs 50, are provided. In this case, each spring 50 is advantageously a compression spring oriented parallel to the direction X10. In this case, each spring 50 is a helical spring, although other types of springs, such as Belleville washers or substantially conical spring washers, can also be provided. Each spring 50 is held in abutment against the support plate 30 with its support axis parallel to the direction X10. In other words, the support plate 30 is interposed between the stack 20 and the springs 50 in the direction X10. Preferably, the springs 50, and thus their respective support axes, are evenly distributed over the surface of the support plate 30, so that the force F30 can be distributed to the stack 20 by the support plate 30 under the collective action of the springs 50. For example, here, three rows of three springs 50 are provided to form a grid of rows and columns parallel to the direction Y10 and the direction Z10.

[0042] 1 and 4, each spring 50 is interposed between the clamp 40 and the support plate 30 in the direction X10. In other words, the clamp 40 is held in contact with each spring 50 in the direction X10. The springs 50 press against the support plate 30 under the action of the clamp 40, causing the support plate 30 to apply a compressive force F30. The springs 50 compress the clamp 40 and are elastically deformed in the direction X10, thereby applying a concentrated force to the support plate 30 in the direction X10 due to their elastic force. The support plate 30 transmits this force to the stack 20 in the form of a compressive force F30.

[0043] Preferably, the pairs of sliding plates 71 and 72 are distributed at the lateral ends of the plate 30. Advantageously, in a plane perpendicular to the direction X10, the two pairs of sliding plates 71 and 72 are arranged on either side of the spring 50, or possibly between the springs 50 of one of the rows of springs arranged on the exterior. Advantageously, in a plane perpendicular to the direction X10, the pairs of sliding plates 71 and 72 are arranged to surround the clamp 40, or possibly to penetrate the clamp 40 near its periphery. For example, the first pair of sliding plates 71 and 72 are arranged obliquely transverse to the second pair of sliding plates 71 and 72, the oblique transverse direction being oblique to the directions Y10 and Z10 and perpendicular to the direction X10.

[0044] Preferably, the fuel cell comprises a sliding connection 80 between the support plate 30 and the clamps 40, called clamp sliding connection 80, which is formed inside the casing 10. The clamps 40 are slidably guided relative to the support plate 30 in the compression direction X10 by the clamp sliding connection 80. In other words, the clamp sliding connection 80 prevents the clamps 40 from pivoting as a whole relative to the plate 30 and prevents the clamps 40 from displacing relative to the plate 30 in directions transverse to the direction X10, in particular in the directions Y10 and Z10. The clamp sliding connection 80 therefore makes it possible to stabilize the clamps 40 and the stack 20 not only during the manufacture of the fuel cell but also during its use.

[0045] In this example, as can be seen in Figures 1, 2 and 4, the clamp slide connection 80 comprises a primary clamp slide 81 and a secondary clamp slide 82, which are distributed in pairs.

[0046] In this example, two pairs of clamp slides 81 and 82 are provided. At a minimum, one pair of primary clamp slide 81 and secondary clamp slide 82 is provided. Each primary clamp slide 81 is preferably fixedly mounted relative to the support plate 30. Each secondary clamp slide 82 is preferably fixedly mounted relative to the clamp 40. For each pair, the clamp slides 81 and 82 are received within each other so as to slide relatively according to the direction X10, thus guiding the sliding of the support plate 30 relative to the clamp 40.

[0047] In this example, for a given primary clamp slide 81, and possibly for each primary clamp slide 81, the primary clamp slide 81 is constituted by a rod parallel to the direction X10 and mounted on the plate 30, thereby fixedly attaching it to the plate 30. For example, each rod projects from the plate 30 in the direction of the clamp 40.

[0048] In this example, for a given secondary clamp slide 82, and possibly for each secondary clamp slide 82, the secondary clamp slide 82 comprises a slide bore parallel to the direction X10, in this case formed by the clamp 40 itself and thereby fixedly attached to the clamp 40. Advantageously, each slide bore opens in the direction X10 towards the plate 30 and in alignment with the corresponding rod, thereby receiving said rod in the sliding manner.

[0049] Preferably, the pairs of clamp slides 81 and 82 are distributed across the surface of the plate 30. In this case, two pairs of clamp slides 81 and 82 are arranged between the springs 50. In particular, as can be seen in Figure 2, the pairs of clamp slides 81 and 82 are arranged on diagonally opposite sides of a centrally located spring 50, on either side of the centrally located spring 50 in the row of centrally located springs 50. Advantageously, the axis X20 passes through the central spring 50. The first pair of clamp slides 81 and 82 is arranged between the central spring 50 and another spring 50 located at a corner of the grid of springs 50. The second pair of clamp slides 81 and 82 is arranged between the central spring 50 and another spring 50 located at the opposite corner of the grid of springs 50. For example, a first pair of clamp slides 81 and 82 are disposed diagonally across central spring 50, diagonally across directions Y10 and Z10, and perpendicular to direction X10. For example, a second pair are disposed diagonally across central spring 50 in the same diagonal direction, but in the opposite direction to the first pair.

[0050] Preferably, when two pairs of sliding plates 71, 72 and two pairs of clamp slides 81, 82 are provided, they are arranged according to a quadrilateral when viewed in projection onto a plane perpendicular to direction X10, with one pair of sliding plates 71, 72 and one pair of clamp slides 81, 82 arranged alternately and consecutively around the periphery of this quadrilateral. In other words, the two pairs of sliding plates 71, 72 are located at both ends of a first diagonal of the quadrilateral, and the two pairs of clamp slides 81, 82 are located at the ends of a second diagonal of the quadrilateral that intersects with the first diagonal near the center of clamp 40 and / or central spring 50.

[0051] In the present example, the clamp 40 forms an open work frame extending generally according to a plane perpendicular to the direction X10, but the clamp 40 can also be realized in the form of a non-open work plate.

[0052] As can be seen in FIG. 2 , the clamp 40 includes a main arm 41, which is parallel to the direction Z10, for example, and secondary arms, here secondary arms 42, 43, 44, 45, 46, and 47, which are parallel to the direction Y10. The secondary arms 42 to 47 are rigidly connected to the main arm 41, for example, to form a monoblock piece integrally with the main arm 41. For example, the secondary arms 42, 43, and 44 extend from the main arm 41 in the direction Y10 and are parallel and spaced apart from each other. For example, the secondary arms 45, 46, and 47 extend from the main arm 41 in the direction opposite to the direction Y10 and are parallel and spaced apart from each other. In this case, the secondary arms are distributed in pairs in that, in the direction Y10, arm 42 is aligned with arm 45, arm 43 is aligned with arm 46, and arm 44 is aligned with arm 47. Preferably, the number of pairs of arms is equal to the number of rows of springs 50. In this case, there are three rows of three springs 50, and therefore three pairs of secondary arms.

[0053] Each of the sub-arms 42 to 47 receives one of the springs 50 in a supporting state in the direction opposite to the direction X10. The sub-arms 42, 43, and 44 each receive the springs 50 of the first row in a supporting state. The sub-arms 45, 46, and 47 each receive the springs 50 of the second row in a supporting state. The main arm 41 receives the springs of a third row, which is disposed between the first and second rows, in a supporting state in the direction opposite to the direction X10.

[0054] Preferably, each bore forming one of the clamp slides 82 is formed on the part of clamp 40 connecting two secondary arms and one primary arm, for example formed integrally with said arms. In this case, one of these bores is formed on the part of clamp 40 connecting arms 41, 42, and 43, and the other bore is formed on the part of clamp 40 connecting arms 41, 46, and 47.

[0055] As described above, regardless of the embodiment of the clamp 40, each elastically deformed spring 50 can apply a concentrated force to the support plate 30 by compressing the clamp 40 in the direction opposite to direction X10, so that the support plate 30 itself applies a force F30 to the stack 20.

[0056] The clamps 40 themselves are held relative to the base plate 11 by draw plates 60 in the direction opposite to direction X10, with each draw plate 60 attached to a clamp 40 on one side and to the base plate 11 on the other side. By being held by draw plates 60 in this manner, the clamps 40 are held relative to the base plate 11 in direction X10, unlike the support plates 30, which may be displaced relative to the base plate 11 in direction X10 under the influence of deformation of the stack 20 during use of the fuel cell. However, as will be explained below, the compressive force applied by the springs 50 to the stack 20 can be adjusted by adjusting the position of the clamps 40 relative to the base plate 11 in direction X10 by the draw plates 60.

[0057] Preferably, the clamp 40 is held in the direction opposite to the direction X10 by only the draw plate 60. In particular, it is advantageous not to hold the clamp 40 against the base plate 11 in the direction parallel to the direction X10 by other elements such as ties or rods. In particular, the clamp 40 is not held against the base plate 11 in the direction parallel to the direction X10 by the casing 10. To apply the force F30, the support plate 30 is attached to the base plate 11 and held against the base plate 11 by a series of elements consisting of the draw plate 60, the clamp 40, and the spring 50, in that order.

[0058] In this example, as can be seen in Figures 1 and 3, exactly two draw plates 60 are provided. It is also possible to provide more than two draw plates 60. However, the advantage of providing draw plates 60 other than individual ties, such as rods, is that it facilitates fuel cell assembly by limiting the number of pieces to be assembled. In other words, it may be preferable to have as few draw plates 60 as possible. In fact, each draw plate 60 is likely to perform the same function by itself as would be performed by a number of separate rods.

[0059] The draw plates 60 are distributed around the stack 20. In particular, the draw plates 60 are distributed around the axis X20. If an even number of plates 60 is provided, the draw plates 60 are preferably arranged in pairs of plates 60, with each pair of plates 60 located on either side of the stack 20, preferably on diagonally opposite sides of the stack 20, in particular with respect to the axis X20. Preferably, in each pair of plates 60, the two plates 60 are parallel to each other.

[0060] The draw plates 60 can be seen in more detail in Figures 3-5. Each draw plate 60 has a generally flat shape and extends parallel to direction X10. In this case, each draw plate 60 extends in a respective plate plane P60, which is therefore parallel to direction X10 and, here, perpendicular to direction Y10. The stack 20, support plate 30, and spring 50 are disposed between the plates 60.

[0061] Each draw plate 60 is spaced apart from any other draw plate 60. In other words, the plates 60 are not attached to each other by any means other than the base plate 11 and the clamps 40.

[0062] Each draw plate 60 includes an anchor consisting of a primary anchor 61 and a secondary anchor 62. The primary anchor 61 attaches the draw plate 60 to the base plate 11 in the direction X10, thereby holding the draw plate 60 relative to the base plate 11 in the direction opposite to the direction X10. The secondary anchor 62 attaches the draw plate 60 to the clamp 40 in the direction X10, thereby holding the draw plate 60 in the direction X10. These configurations ensure that the stack 20 is maintained in a compressed state between the base plate 11 and the support plate 30 in the compression direction X10 by the primary anchor 61 and the secondary anchor 62 under the action of the spring 50 compressing the clamp 40. In other words, the draw plate 60, which holds the clamp 40 relative to the base plate 11, allows the support plate 30 to apply a force F30 to the stack 20 under the action of the spring 50 compressing the clamp 40.

[0063] Preferably, each draw plate 60 advantageously occupies at least 50% or even at least 70% of the width L20 of the stack 20, where the width L20 of the stack is measured perpendicular to the direction X10 and parallel to the associated draw plate 60.

[0064] Advantageously, each draw plate 60 includes a single common tie 63 and a plurality of individual ties 64. Each individual tie 64 is attached to the common tie 63, and the position of each individual tie 64 relative to the common tie 63 is preferably adjustable in the direction X10. Advantageously, the common tie 63 supports all primary anchors 61 of the draw plate 60, while each individual tie 64 carries only one of the secondary anchors 62 of the draw plate 60, so that any secondary anchor 62 of a plate 60 is supported by one of the individual ties 64 of said plate 60. Alternatively, the primary anchors 61 may be carried by the individual ties 64, and the secondary anchors may be carried by the common tie 63. Alternatively, it is also conceivable to distribute the anchors 61 and 62 between the ties 63 and 64.

[0065] Advantageously, in the direction X10, the common ties 63 occupy at least 50%, or even at least 70%, and even more preferably at least 90% of the length of the draw plate 60, while the remaining percentage of the length of the plate 60 is occupied by the individual ties 64. Preferably, the common ties 63 advantageously occupy at least 50%, or even at least 70%, of the width L20 of the stack 20, where the width L20 is measured perpendicular to the direction X10 and parallel to the associated plate 60.

[0066] In this example, with the primary anchor 61 supported at one end of the draw plate 60, the common tie 63 extends from the primary anchor 61, in other words, from the base plate 11, in the direction opposite to direction X10, i.e., toward the clamp 40. In this example, with the secondary anchor 62 supported at the other end of the draw plate 60, the individual ties 64 extend from the secondary anchor 62, in other words, from the clamp 40, in direction X10, i.e., toward the base plate 11. Each individual tie 64 is attached to the common tie 63 between the base plate 11 and the clamp 40, in other words, between the anchors 61 and 62.

[0067] The common tie 63 takes the form of a solid plate or an open work lattice extending according to the plane P60 of the draw plate 60. In this example, the common tie 63 takes the form of an open work lattice, which has the advantage that the common tie 63 is lighter in weight.

[0068] Preferably, the common tie 63 includes three stringers 65. Each stringer 65 is a rigid linear member. Each stringer 65 is parallel to the direction X10. The stringers 65 are arranged according to the plane P60 of the draw plate 60.

[0069] Preferably, all stringers 65 have the same length. Each stringer 65 extends to one of the individual ties 64 that extend it parallel to the direction X10. Each stringer 65 terminates between the clamp 40 and the base plate 11, preferably at the level of the support plate 30. Each individual tie 64 is attached to the common tie 63 via one of the stringers 65. In the direction X10, each stringer 65 advantageously extends up to, and preferably penetrates, the base plate 11. Advantageously, at the level of the base plate 11, each stringer 65 supports one of the primary anchors 61. Preferably, in the direction X10, each stringer is axially aligned with the primary anchor 61 it supports and with the secondary anchor 62 carried by the individual tie 64 attached to this stringer 65. In other words, each stringer 65 is axially aligned with and disposed between two anchors 61 and 62 of the draw plate 60 in the compression direction X10. Therefore, ignoring manufacturing and assembly tolerances, each stringer 65 and corresponding individual tie 64 is subjected only to tension by the anchors 61 and 62 parallel to the direction X10. Therefore, generally, ignoring manufacturing and assembly tolerances, the draw plate 60 is subjected only to tension.

[0070] Preferably, for each, if not all, draw plates 60, at least two stringers 65, i.e., the stringers located at the edges of the draw plates 60, are separated by an inter-stringer distance L65 that is more than 50%, or even more than 70%, of the width L20 of the stack 20. This inter-stringer distance L65 is measured perpendicular to the direction X10 according to the plane P60 of the plate 60 and parallel to the width L20 of the stack 20. More generally, in the direction parallel to the width L20, the plate 60 is particularly wide, the anchors 61 are particularly spaced apart from one another, and the anchors 62 are particularly spaced apart from one another, so that the plate 60 effectively absorbs torsional or bending forces that may be applied to the stack 20.

[0071] Preferably, each draw plate 60 includes one or more crosspieces 66, here three crosspieces 66. Each crosspiece 66 is oriented transversely, preferably perpendicularly, to direction X10 and preferably extends in plane P60. Thus, each crosspiece 66 is transversely, preferably perpendicularly, to the stringers 65. Each crosspiece 66 rigidly connects at least two stringers 65 to each other, even if not all of the stringers 65 of the plate 60, as in this example. Overall, the stringers 65 of the plate 60 are rigidly attached to each other by the crosspieces 66, so the common tie 63 is rigid. For each plate 60, the stringers 65 and crosspieces 66 form the aforementioned lattice. As in this example, the stringers 65 and crosspieces 66 of the plate 60 can define openings, thereby configuring the plate 60 to be an openwork plate. Alternatively, these openings can be filled to form a solid plate. The crosspieces 66 rigidly connect the stringers 65 together, thereby making it possible to absorb bending and / or shear forces that may be exerted on the stack 20, thereby making the overall stability and resistance particularly high. Preferably, at least one crosspiece 66 is arranged in the direction X10 between the clamp 40 and the base plate 11, in particular between the anchors 61 and 62, in particular between the ends of the common tie 63. This arrangement applies here to all crosspieces 66 of the plate 60.

[0072] 3 and 5, each stringer 65 is received in a respective notch 16 belonging to the base plate 11 and passes through said notch 16. Advantageously, each notch 16 is formed on the peripheral edge of the base plate 11. Each notch 16 passes completely through the base plate 11 in the direction X10 and is completely penetrated by the stringer 65. On one side of the base plate 11 located opposite the stack, the anchors 61 compress the base plate 11 in the direction opposite to the compression direction X10, preferably at the exit of the notch 16. Preferably, the base plate 11 comprises one or more recesses 17 formed on this side of the base plate 11, thereby concavely accommodating the anchors 61 within the base plate 11 and thereby limiting or even preventing movement of the anchors 61 relative to the plate in the two transverse directions Y10 and Z10, preferably in both transverse directions Y10 and Z10. In this case, the notch 16 opens into the recess 17, thereby allowing the anchor 61 to engage in the notch 16 in a transverse direction perpendicular to the plane P60.

[0073] Preferably, at least one of the anchors 61, or even each anchor 61, has at least one wing 67, or even two wings 67. Here, each anchor 61 has two wings 67. Each wing 67 extends transversely to the direction X10, in particular according to the plane P60, and projects radially from the stringer 65. Here, for each stringer 65, two wings 67 are formed on either side of the stringer 65. For two adjacent anchors 61, the adjacent wings 67, one belonging to one of the two anchors 61 and the other to the other of the two anchors 61, can be configured to be connected, as in the case of the left side of FIG. 5, or separated, as in the case of the right side of FIG. 5. By means of the wings 67, the anchor 61 presses against the base plate 11 in the direction opposite to the direction X10. Advantageously, each wing 67 is configured to be received in a recess 17. The wings 67 attach the draw plate 60 to the base plate 11, thereby holding it in the direction opposite to the direction X10. When the wings 67 are located in the plate plane P60, the attachment of the draw plate 60 to the base plate 11 causes little or no bending stress on the draw plate 60, except for local bending stress at the height of the wings 67. Preferably, the draw plate 60 is not fixed to the base plate 11 but is held only in the direction opposite to the direction X10 by the anchors 61, where the stringers 65 are received in the notches 16 to position the draw plate 60 transversely to the base plate 11, i.e., transversely to the direction X10. This limits stress concentration at the height of the anchors 61 and facilitates assembly of the draw plate 60, since the draw plate 60 does not need to be fixed to the base plate 11.

[0074] Preferably, as shown in FIG. 5 , each notch 16 opens transversely to the direction X10 over its entire length, in this case, in the direction X10. Because each notch 16 opens transversely, as the draw plate 60 approaches its final orientation, each stringer 65 can be introduced into the respective notch 16 by translating the draw plate 60 parallel to the direction Y10 relative to the base plate 11. Finally, each stringer 65 is received in the respective notch 16, and the anchor 61 is positioned against the base plate 11. If recesses 17 are provided, the recesses 17 can be configured to open transversely, in this case, in the direction Y10, similarly to the notches 16, so that the anchor 61 can be received by introducing it parallel to the direction Y10. This configuration allows the draw plate 60 to be introduced into all of the notches 16 at once, facilitating assembly of the plate 60 to the clamp 40, preferably in a single operation without using tools.

[0075] Preferably, each draw plate 60 has the same number of primary anchors 61 as secondary anchors 62, here three anchors each. Preferably, each draw plate 60 has the same number of stringers 65 as individual ties 64, here three each. Preferably, each draw plate 60 has the same number of stringers 65 as primary anchors 61, here three each. Preferably, each draw plate 60 has the same number of individual ties 64 as secondary anchors 62, here three each.

[0076] For each draw plate 60, the individual ties 64 are preferably arranged according to a plane P60 and distributed across the entire width of the plate 60. Preferably, each individual tie 64 is in the form of a rod or elongated element parallel to the direction X10. This rod extends parallel to the direction X10 through the stringers 65, if one of these stringers 65 is provided for the common tie 63. Each individual tie 64 is attached to the common tie 63, and in particular to one of the stringers 65 of the common tie 63. This attachment is made at one end of the individual tie 64 and at the corresponding end of the stringer 65. Preferably, in the direction X10, each tie 64 is axially aligned with the secondary anchor 62 it supports and with the primary anchor 61 carried by the stringer 65 attached to this individual tie 64. In other words, each tie 64 is axially aligned with and disposed between two anchors 61 and 62 of the draw plate 60 in the compression direction X10.

[0077] Each tie 64 is preferably rigid, similar to the stringers 65, if provided, or similar to the common tie 63. Unlike the stringers 65, which are interconnected by crosspieces 66, the ties 64 are not interconnected except by the connections of the common tie 63 to the clamps 40 and draw plates 60. Preferably, all ties 64 have the same length.

[0078] Preferably, for each draw plate 60, if not for all draw plates 60, at least two ties 64, i.e., ties located at the edge of the draw plate 60, are separated by an inter-tie distance L64 that is more than 50%, or even more than 70%, of the width L20 of the stack 20. Distances L64 and L65 are advantageously equal or similar distances. The inter-tie distance L64 is measured perpendicular to the direction X10 according to the plane P60 of the draw plate 60 and parallel to the width L20 of the stack 20.

[0079] In the direction opposite to the direction X10, each tie 64 reaches up to the clamp 40, preferably to the crosspiece. Preferably, as can be seen in Figures 3 and 4, each individual tie 64 is received in a respective notch 18, wherein each notch 18 is formed in the clamp 40 and each individual tie 64 passes through said respective notch 18. Advantageously, each notch 18 is formed at the end of one of the arms 42, 43, 44, 45, 46 and 47 of the clamp. Each notch 18 passes completely through the clamp 40 in the direction X10 and is completely penetrated by the tie 64. On one side of the clamp 40 opposite the stack 20, the anchor 62 presses against the clamp 40 in the compression direction X10, in particular against one of the arms 42 to 47, preferably at the opening of the notch 18. Preferably, clamp 40 includes a counterbore or recess formed on this side of clamp 40 for each anchor to recess the anchor 62 within clamp 40. In this case, notch 18 opens into the counterbore or recess.

[0080] Preferably, at least one of the anchors 62, or even each anchor 62, forms a head, for example a screw head, that is fixedly attached to the end of a tie 64 that supports that anchor 62. Preferably, the head is made from the material that comprises the tie 64. In this case, it is possible for the screw to be configured to form both the tie 64 and the anchor 62 that is carried by that tie 64.

[0081] Advantageously, the anchors 62 are configured to extend in the plane P60, that is, to extend perpendicularly to the plane P60 without offset from the plane P60. Their heads cause the anchors 62 to press against the clamp 40 in the direction X10. The heads of the anchors 62 attach the draw plate 60 to the clamp 40 and hold it in the direction X10. When the anchors 62 are positioned in the plate's plane P60, the attachment of the plate 60 to the clamp 40 generates almost no or no bending stresses on the plate 60, except for those that occur locally at the height of the anchors 62. Preferably, the plate 60 is not fixed to the clamp 40 but is held only in the direction X10 by the anchors 62, which receive the ties 64 in the notches 18 and position it transversely to the direction X10, i.e., transversely to the clamp 40. This limits stress concentrations at the height of the anchors 62 and facilitates assembly of the plate 60. This is because there is no need to fix the plate 60 to the clamp 40 .

[0082] Preferably, each individual tie 64 is connected to the common tie 63 by a respective helical connection 68 centered on an axis coaxial with the individual tie 64 and the corresponding stringer 65, thereby allowing each individual tie 64 to be individually adjusted in position relative to the common tie 63 in the direction X10. In practice, this helical connection 68 may comprise an external thread formed on the end of the individual tie 64 and an internal thread formed within a hole carried at the end of the associated stringer 65. The external thread of the tie 64 is received within the hole of the stringer 65 and threaded into the internal thread. Thus, when the tie 64 is pivoted about its own axis relative to the tie 63, displacement of the tie 64 relative to the tie 63 in the direction X10 is achieved independently of the other ties 64. If the anchor 62 is carried by the tie 64, adjusting the position of the tie in the direction X10 allows adjustment of the position of the anchor 62 relative to the common tie 63 in the direction X10. Thus, each anchor 62 can be individually adjusted in position by adjusting the position of the clamp 40 using the ties 64, thereby adjusting the force F30 applied by the support plate 30.

[0083] 3, each notch 18 preferably opens transversely to direction X10, here in direction Y10, over its entire length. This transverse opening allows the draw plate 60 to translate parallel to direction Y10 relative to the clamp 40 by closing the plate 60 in a final direction, thereby introducing each tie 64 into its respective notch 18, until each tie 64 is received in its respective notch 18 and the anchor 62 is positioned against the clamp 40. If a counterbore or recess for receiving the anchor 62 is provided on the clamp, the counterbore or recess may be configured to open transversely, here in direction Y10, like the notches 18, so that the anchor 62 can be received in the counterbore or recess by introducing it parallel to direction Y10. These configurations allow the plate 60 to be introduced into all of the notches 18 at once, facilitating assembly of the plate 60 to the clamp 40, preferably in a single motion without the use of tools.

[0084] Assembly is further simplified by the open notches 16 and 18, which allow the draw plate 60 to be attached to both the clamps 40 and base plate 11 at once, with the clamps 40 and base plate 11 already surrounding the stack 20, by lateral translation of the draw plate 60 in the direction of the clamps 40 and base plate 11 via the springs 50 and support plate 30. Once the plate 60 is attached, stack clamping is performed by adjusting the position of the individual ties 64, here by screwing them, in the direction X10, gradually tightening the stack 20 until the desired final force F30 is achieved.

[0085] In the illustrated example, the clamp 40 is a single clamp. Furthermore, the clamp 40 is fabricated as a single monoblock, e.g., a cast metal piece. However, the clamp 40 can also be fabricated from multiple, independent parts. For example, each pair of secondary arms (42, 45), (42, 46), and (44, 47), each formed from two secondary arms extending in opposite directions in the direction Y10, can be configured to form a part of a clamp independent of the other parts. In the case of a clamp with four pairs of secondary arms, each consisting of two secondary arms extending in opposite directions in the direction Y10, a clamp can be provided that is made up of two independent parts, each of which has its own main arm parallel to the direction Z10 and two pairs of secondary arms each formed from two secondary arms extending in opposite directions in the direction Y10 from the main arm of the associated part. Preferably, each part of the clamp is symmetrical about a central plane perpendicular to the direction Y10. Even if there is a clamp consisting of several separate parts, the entire clamp thus configured is acted upon by two draw plates 60 with anchors 61, 62, each of which is attached to the base plate 11 and to each of the parts of the clamp 40. The draw plates 60 therefore ensure that the stack 20 is kept compressed between the base plate 11 and the support plate 30 in the compression direction X10 by the anchors 61, 62 under the action of the springs 50 which press against the different parts of the clamp 40. Preferably, for the different separate parts of the clamp, a second sliding connection can be provided, in particular as described above, so that the separate parts of the clamp 40 are slidably guided relative to the support plate 30 in the compression direction X10.

[0086] Any feature described above with respect to one embodiment or alternative can also be implemented with respect to any other embodiment or alternative described, where technically possible. [Explanation of symbols]

[0087] 10 Casing 11 Base Plate 12 Lateral wall 13 Vertical wall 14 Rug 15 Sliding sleeve 16 notches 17 Recess 18 notches 20 stacks 21 Electrochemical Cell 30 Support Plate 40 Clamp 41 Main arm 42 Secondary Arm 43 Secondary Arm 44 Secondary Arm 45 Secondary Arm 46 Secondary Arm 47 Secondary Arm 50 central spring 60 Draw Plate 61 Primary Anchor 62 Secondary Anchor 63 Common Ties 64 Individual Ties 65 Stringer 66 Cross Piece 67 Wings 68 Spiral connection 70 Sliding connection plate, sliding connection part 71 Primary sliding plate 72 Secondary sliding plate 80 Clamp sliding connection 81 Primary clamp sliding part 82 Secondary clamp sliding part F30 Compression Force L20 width L64 Distance between ties L65 Stringer Distance P60 Plate Flat X10 Compression direction X20 center axis Y10 First horizontal Z10 Second Horizontal

Claims

1. A fuel cell, A base plate (11); a stack (20) including electrochemical cells (21) stacked in a compression direction (X10) and held in abutting contact with the base plate (11) in the compression direction (X10); 1. A compression system comprising: a support plate (30) movable relative to the base plate (11) in a direction parallel to the compression direction (X10) and held in abutting contact with the stack (20) in the compression direction (X10); a spring (50) held in abutting contact with the support plate (30) in the compression direction (X10); and A clamp (40) held in abutting contact with the spring (50) in the compression direction (X10). a compression system comprising: In a fuel cell comprising: The fuel cell includes a first sliding connection (70), and the support plate (30) is slidably guided relative to the base plate (11) in the compression direction (X10) by the first sliding connection (70); the compression system further comprises draw plates (60) separated from one another, each draw plate (60) having an anchor (61, 62) by which the draw plate (60) is attached to the base plate (11) and the clamp (40), such that the draw plate (60) ensures that the stack (20) is maintained in compression between the base plate (11) and the support plate (30) in the compression direction (X10) by the anchors (61, 62) under the action of the spring (50) pressing against the clamp (40).

2. 2. The fuel cell of claim 1, wherein the first sliding connection (70) comprises a primary sliding part (71) attached to the support plate (30) and a secondary sliding part (72) attached to the base plate (11), the primary sliding part (71) and the secondary sliding part (72) being received within each other and thereby sliding relative to each other in the compression direction (X10), thus guiding the sliding of the support plate (30) relative to the base plate (11).

3. The fuel cell comprises a casing (10), the casing (10) containing the stack (20), the compression system, and the clamp (40), and the casing (10) is fixedly mounted to the base plate (11); 3. The fuel cell of claim 2, wherein the secondary sliding portion (72) is fixedly attached to the casing (10), preferably at a height position of the clamp (40) or the spring (50) in the compression direction (X10), thereby being fixedly attached to the base plate (11).

4. 4. The fuel cell according to claim 1, wherein each draw plate (60) comprises a common tie (63) and individual ties (64), the common tie (63) and the individual ties (64) supporting the anchors (61, 62), and each individual tie (64) is attached to the common tie (63) and is positionally adjustable relative to the common tie (63) in the compression direction (X10) to adjust the position of the anchor (61) for attaching the draw plate (60) to the base plate (11) and the position of the anchor (62) for attaching the draw plate (60) to the clamp (40).

5. 5. The fuel cell of claim 4, wherein each individual tie (64) is connected to the common tie (63) by a spiral connection parallel to the compression direction (X10) so that the position of each individual tie (64) relative to the common tie (63) can be adjusted.

6. 6. The fuel cell according to any one of claims 1 to 5, wherein each draw plate (60) comprises stringers (65) parallel to the compression direction (X10).

7. 7. The fuel cell of claim 6, wherein each draw plate (60) comprises a crosspiece (66) fixedly connected to the stringer (65) to rigidly connect the stringers (65) to one another, the crosspiece (66) being disposed between the clamp (40) and the base plate (11).

8. 8. The fuel cell according to claim 6 or 7, wherein for each draw plate (60), at least two stringers (65) are spaced apart by a stringer-to-stringer distance (L65) that is greater than 50% of the width (L20) of the stack (20), the stringer-to-stringer distance (L65) being measured perpendicular to the compression direction (X10), and the width (L20) of the stack (20) being measured parallel to the stringer-to-stringer distance (L65).

9. 9. The fuel cell according to claim 6, wherein each stringer (65) is axially aligned with one of the anchors (61, 62) of the draw plate (60) in the compression direction (X10), and preferably with two of the anchors (61, 62) of the draw plate (60), and is disposed between two of the anchors (61, 62).

10. 10. The fuel cell of claim 6, wherein at least one of the anchors comprises at least one wing extending radially from the stringer and pressing the base plate in a direction opposite to the compression direction, thereby attaching the draw plate to the base plate, and wherein the at least one wing is disposed in a plane in which the stringer extends.

11. 11. The fuel cell of claim 1, wherein for each draw plate (60), the anchors (61, 62) comprise a primary anchor (61) for attaching the draw plate (60) to the base plate (11) and a secondary anchor (62) for attaching the draw plate (60) to the clamp (40).

12. 12. The fuel cell of claim 1, wherein the draw plates (60) comprise a first draw plate (60) and a second draw plate (60) parallel to each other.

13. 13. The fuel cell of claim 12, wherein the first draw plate (60) and the second draw plate (60) are disposed on either side of the stack (20) in opposite directions relative to the stack (20).

14. 14. The fuel cell according to claim 1, wherein the fuel cell comprises a second sliding connection (80), and the clamp (40) is slidingly guided relative to the support plate (30) in the compression direction (X10) by the second sliding connection.

15. 15. The fuel cell according to any one of claims 1 to 14, wherein the clamp (40) is made from different parts that are independent of each other.

Images