Fuel cell

Abstract

The invention relates to a proton exchange membrane fuel cell (1) or electrolyzer, comprising a stack of a plurality of cells (30), the stack being sandwiched between a first clamping plate (23) and a second clamping plate (23) to apply a predetermined clamping pressure to the stack, one of the clamping plates (23) having at least one conical bearing surface (43) opening into a through hole, the fuel cell (1) comprising at least one clamping device including a tie rod (44) and a conical washer (45) received by the conical bearing surface (43) such that the conical portions are opposite each other, the tie rod (44) being held in position by one of its ends by the conical washer (45) so as to apply the clamping pressure to the stack. (Short figure: Fig. 1)

Description

Title of the invention: Fuel cell

[0001] The present invention relates to a fuel cell, in particular of the proton exchange membrane fuel cell (“PEMFC”) type, comprising a stack of elementary cells, the cells each comprising an anodic plate and a cathodic plate sandwiching a Membrane Electrode Assembly (MEA).

[0002] In such a stack, the stack is sandwiched between two clamping plates to apply a determined clamping pressure to the stack, and at least one end of the stack comprises a current-collecting plate that conducts electricity and is electrically connected to the cells of the stack to collect the sum of the electrical currents produced by the cells. A tie rod is used to maintain the clamping force of such a stack.

[0003] Such a tie rod can break when the battery is subjected to vibrations. Furthermore, when the tie rod is covered by insulation, the insulation can wear out when the battery is subjected to these vibrations or when it receives shocks. Finally, the tie rod can generate a short circuit between the tie rod and the cells if it is not correctly centered with respect to the openings in the cells.

[0004] The present invention aims to effectively remedy these drawbacks by proposing a proton exchange membrane fuel cell or an electrolyzer, comprising a stack of a plurality of cells, the stack being sandwiched between a first clamping plate and a second clamping plate, to apply a predetermined clamping pressure on the stack, one of the clamping plates having at least one conical bearing opening into a through hole, the stack having at least one clamping device comprising a tie rod and a conical washer received by the conical bearing so that the conical parts are opposite each other, the tie rod being held in position by one of its ends, by the conical washer so as to apply the clamping pressure on the stack.

[0005] Such an arrangement allows for automatic realignment of the stack in the event of shock or vibration. This prevents any short circuit between the tie rod and the openings provided in the cells for the passage of the tie rod. Furthermore, when the tie rod is covered with thermal and / or electrical insulation, its wear is reduced, thanks to the space that permanently exists between the through hole and the tie rod.

[0006] Finally, such an arrangement allows for a homogeneous tightening of the stack, which makes it possible to avoid a break in the tie rod when the stack is subjected to vibrations.

[0007] According to one embodiment, the conical bearing and the conical washer are arranged so that a space exists, in particular a circular ring, between the tie rod and the hole passing through the conical washer.

[0008] According to one embodiment, the conical bearing and the conical washer are arranged so that a space exists permanently all around the tie rod, between the tie rod and the through hole of the conical washer.

[0009] According to one embodiment, the tie rod passes completely through the conical washer.

[0010] Such an arrangement makes it easier to assemble the stack.

[0011] According to one embodiment, the conical bearing surface is provided on the face of the clamping plate opposite the stacking.

[0012] According to one embodiment, the clamping device includes a nut screwed onto the tie rod to clamp the conical washer against said clamping plate or the clamping device includes a compensation member to compensate for the dimensional change due to the cells of the stack, the compensation member including in particular a spring disposed around the tie rod, the compensation member being disposed axially between the conical washer and a limit switch member, to allow the compensation member to cause a relative displacement of the limit switch member with respect to the conical washer.

[0013] Alternatively, the conical washer has a thread and the conical washer is screwed onto the tie rod.

[0014] According to one embodiment, the limit switch member has a thread and is screwed onto the tie rod.

[0015] According to one embodiment, the tie rod is held at its ends by a flat of the conical washer and by a flat of the end-of-stroke member.

[0016] According to one embodiment, the compensation member is arranged so as to maintain a play between the conical washer and the end-of-stroke member.

[0017] According to one embodiment, the clamping device includes, on the side of the other clamping plates, a nut screwed onto the tie rod to apply a clamping force on the other of the clamping plates, or a tapping provided in the other of the clamping plates to receive a second of the ends, in particular threaded, of the tie rod.

[0018] Alternatively, the other of the clamping plates has at least one conical bearing opening into a through hole, the clamping device having at least two conical washers, each washer being received respectively by the conical bearing of one and the other of the clamping plates, the tie being held in position at each of its ends, by the conical washers so as to apply the clamping pressure on the stack.

[0019] According to one embodiment, each cell has an opening for the passage of the tie rod, the diameter of the opening being strictly greater than the internal diameter of the conical washer.

[0020] According to one embodiment, the ratio of the diameter of the orifice to the internal diameter of the The conical washer is predetermined to avoid contact between the tie rod and the cells after centering the tie rod, the ratio being in particular greater than 1.3, for example greater than 1.8.

[0021] According to one embodiment, the inner diameter of the conical washer at one end of the tie rod is strictly less than the inner diameter of the conical washer at the other end of the tie rod.

[0022] Such an arrangement allows the installation of a compensation device.

[0023] According to one embodiment, the clamping device comprises a plurality of tie rods.

[0024] According to one embodiment, each tie rod is held in position by at least one conical washer, in particular by two conical washers.

[0025] According to one embodiment, the tie rod is devoid of thermal and / or electrical insulation along the stack, particularly around the perimeter of the tie rod.

[0026] Alternatively, the tie rod has thermal and / or electrical insulation around its perimeter.

[0027] In such a case, the invention makes it possible to avoid wear of the insulation, thanks to the space which exists permanently between the through hole and the tie rod, therefore between the openings of the cells and the tie rods.

[0028] According to one embodiment, the plurality of cells comprises a first cell at a first end of the stack and a last cell at a second end of the stack, each cell of the plurality comprising an anodic plate and a cathodic plate sandwiching a Membrane Electrode Assembly.

[0029] According to one embodiment, one of the plates of the first cell forms with one of the plates of another of the cells, a first inter-cell cooling circuit, the other of the plates of the first cell defining a first end plate, one of the plates of the last cell forming with one of the plates of another of the cells, a last inter-cell cooling circuit, the other of the plates of the last cell defining a last end plate.

[0030] According to one embodiment, the battery comprises a distribution plate including a first electric current collection face intended to face a first electric current collection plate and a distribution face intended to face the cooling face of the first end plate.

[0031] According to one embodiment, the distribution manifold is arranged so that all of the fluid entering the distribution manifold passes through the distribution plate in its thickness to distribute the fluid into the first cell.

[0032] According to one embodiment, the distribution plate includes six distribution manifolds, notably for distributing or collecting fuel, oxidizer and coolant.

[0033] According to one embodiment, each anodic or cathodic plate comprises a reactive face and a cooling face opposite each other, the face reactive of each plate being intended to face the Membrane Electrode Assembly and being provided with reliefs and hollows forming a reactive circuit, for the circulation of a reactive fluid, the cooling face of the cathode plate of at least one of the cells being intended to face the cooling face of the anodic plate of another of the cells, defining between them reliefs and hollows to form an inter-cell cooling circuit for the circulation of a cooling fluid.

[0034] According to one embodiment, each cathode or anodic plate includes a reagent inlet manifold formed through the plate and in fluidic communication with the reagent circuit, a reagent outlet manifold formed through the plate and in fluidic communication with the reagent circuit, a cooling fluid inlet manifold formed through the plate, and a cooling fluid outlet manifold formed through the plate.

[0035] According to one embodiment, the battery includes a sealing plate comprising a second electric current collection face intended to face a second electric current collection plate and a sealing face fixed to the cooling face of the last end plate, the sealing face and the cooling face of the last end plate defining between them reliefs and hollows to form a final cooling circuit for the circulation of the cooling fluid.

[0036] The invention will be better understood upon reading the following description and examining the figures. These figures are given only by way of illustration and in no way limit the invention.

[0037] [Fig.1] Fig.1 is a schematic cross-sectional representation of a battery according to the invention;

[0038] [Fig.2] Fig.2 is a schematic cross-sectional representation of a stack according to the invention;

[0039] [Fig.3] The [Fig.3] is a schematic cross-sectional representation of the stack of the [Fig.1] or of [Fig. 2]; and

[0040] [Fig.4] [Fig.4] is a schematic elevation representation of the stack of the [Fig.3].

[0041] Identical, similar, or analogous elements retain the same reference from one figure to another.

[0042] As seen in [Fig. 1], a proton exchange membrane fuel cell 1

[0043] comprises a stack of a plurality of cells 30. The stack is sandwiched between a first clamping plate 23 and a second clamping plate 23, to apply a predetermined clamping pressure to the stack. The first clamping plate 23 has two conical bearing surfaces 43, each opening into a through hole.

[0044] Each conical bearing surface 43 is provided on the face of the first clamping plate 23 opposite the stacking.

[0045] The stack 1 includes at least one clamping device comprising here two tie rods 44 and two conical washers 45.

[0046] Each conical washer 45 is received by one of the conical seats 43 so that the conical parts of the washer and the conical seat are opposite each other and in contact.

[0047] Each tie rod 44 is mounted by one of its ends in one of the conical washers 45 and by another of its ends, either in a nut (the tie rod on the left, in [Fig.1]) or in a threaded hole in the clamping plate 23 (the tie rod on the right in [Fig.1]).

[0048] Each tie rod 44 passes through each of the two conical washers 45 and a nut 49 is screwed onto a threaded end of the tie rod, to tighten the stack, the nut 49 coming against the conical washer 45.

[0049] [Fig.2] illustrates a pile identical to that of [Fig.1], but in which a tie rod held in position by two conical washers is shown.

[0050] The first clamping plate 23 and the second clamping plate 23 each have a conical bearing surface 43 opening into a through hole and the clamping device includes two conical washers 45.

[0051] The conical washer 45 on the side of the first plate 23 is received by the conical bearing surface 43 of the first plate so that the conical parts are opposite each other.

[0052] The conical washer 45 on the side of the second plate 23 is received by the conical bearing surface 43 of the second plate so that the conical parts are opposite each other.

[0053] The tie rod 44 is housed between the two conical washers 45, to apply the clamping pressure on the stack.

[0054] The tie rod 44 passes completely through each of the two conical washers 45.

[0055] As can be seen in [Fig.2], the clamping device further includes a compensation element 47 to compensate for the dimensional change due to the cells 30 of the stack.

[0056] Although not shown in [Fig.1], such a compensating member 47 can be installed at the level of the conical washer 45 of one or each of the tie rods of the stack of [Fig.1].

[0057] The compensating member 47 includes a spring 47 disposed at a first end of the tie rod 44, between the conical washer 45 and a limit switch member 48.

[0058] The compensating member 47 is mounted around the tie rod 44, the tie rod 44 being held at its ends by a flat of the conical washer 45 and by a flat of the limit switch 48. In the example shown in [Fig.2], the limit switch 48 has a threaded hole and is screwed onto a threaded end of the tie rod 44.

[0059] The clamping device includes a nut 49 screwed onto the other end of the tie rod 44, the nut 49 coming into contact with one of the conical washers 45.

[0060] As can be seen in [Fig.3], the plurality of cells 30 comprises a first cell 30 at a first end of the stack and a last cell 30 at a second end of the stack.

[0061] Each cell 30 of the plurality comprises an anodic plate 10 and a cathodic plate 20 sandwiching a Membrane Electrode Assembly 16, one of the plates 10, 20 of the first cell 30 forming with one of the plates 10, 20 of another of the cells 30, a first inter-cell cooling circuit 15, the other of the plates 10, 20 of the first cell 30 defining a first end plate, one of the plates 10, 20 of the last cell 30 forming with one of the plates 10, 20 of another of the cells 30, a last inter-cell cooling circuit 15, the other of the plates 10, 20 of the last cell 30 defining a last end plate.

[0062] The stack 1 includes a distribution plate 11 comprising a first electric current collection face intended to face a first electric current collection plate 24 and a distribution face intended to face the cooling face of the first end plate.

[0063] The stack 1 includes a first seal 19 interposed between the distribution plate 11 and the first clamping plate 17, 23, the distribution plate 11 having at least one distribution collector for a fluid formed through the plate, the first electric current collection face and / or the first clamping plate 17, 23 having an annular lip formed around the distribution collector, so as to pinch the first seal 19 to ensure a seal against the fluid.

[0064] The first electric current collection face has a first embossing to receive the first collector plate 24, so that the distribution plate 11 and the first collector plate 24 together form a flat face to come into contact with the first joint 19.

[0065] The first joint 19 has at least one through hole for the passage of the tie rod.

[0066] The battery 1 comprises a sealing plate 21 including a second face of electric current collection intended to face a second electric current collection plate 25 and a sealing face fixed to the cooling face of the last end plate, the sealing face and the cooling face of the last end plate defining between them reliefs and hollows to form a final cooling circuit for the circulation of the cooling fluid.

[0067] The stack 1 includes a second seal 18 interposed between the second col- plate reader 25 and the second clamping plate 23.

[0068] Fig. 4 represents pile 1 in elevation, before assembly.

[0069] As can be seen in [Fig. 4], each plate 10, 20 comprises:

[0070] - a reagent inlet collector 3, 4 formed through the plate 10, 20 and being in fluidic communication with the reagent circuit via a first light 2 formed through the plate 10, 20; - a reagent outlet collector 6, 7 formed through the plate 10, 20 and being in fluidic communication with the reagent circuit via a second light 2 formed through the plate 10, 20; - a coolant inlet manifold 5 formed through the plate 10, 20; - a coolant outlet manifold 8, 9 formed through the plate 10, 20. - at least two orifices formed through the plate 10, 20, each orifice being arranged to allow fluidic communication only through the plate 10, 20, without being in fluidic communication with the reagent circuit.

[0071] The reagent inlet manifold 3 of an anodic plate 10 is in fluidic communication with one of the orifices of a cathodic plate 20 and the reagent outlet manifold 6 of the anodic plate 10 is in fluidic communication with another of the orifices of the cathodic plate 20.

[0072] The reagent inlet manifold 3 of a cathode plate 20 is in fluidic communication with one of the orifices of an anode plate 10 and the reagent outlet manifold 6 of the cathode plate 20 is in fluidic communication with another of the orifices of the anode plate 10.

[0073] Thus, the stacking allows a distribution of the reactive fluid dedicated to the anodic plates 10 and a distribution of the reactive fluid dedicated to the cathodic plates 20 by forming two independent circuits.

[0074] The sealing face of the sealing plate 21 has a reagent passage 12, 13 formed by reliefs and hollows, to allow fluidic communication between the reagent inlet manifold 3, 4 and the reagent circuit or to allow fluidic communication between the reagent outlet manifold 6, 7 and the reagent circuit.

[0075] The sealing face of the sealing plate 21 has a cooling passage 13 formed by reliefs and hollows, to allow fluid communication between the cooling fluid inlet manifold 5 and the cooling circuit or to allow fluid communication between the cooling fluid outlet manifold 8, 9 and the cooling circuit.

[0076] The reagent passage 12, 13 and the cooling passage 13 can be provided at the sealing face, at the last end plate or on both.

Claims

Demands

1. Proton exchange membrane fuel cell or electrolyzer (1), comprising a stack of a plurality of cells (30), the stack being sandwiched between a first clamping plate (23) and a second clamping plate (23), to apply a predetermined clamping pressure on the stack, one of the clamping plates (23) having at least one conical bearing surface (43) opening into a through hole, the cell (1) having at least one clamping device comprising a tie rod (44) and a conical washer (45) received by the conical bearing surface (43) so that the conical parts are opposite each other, the tie rod (44) being held in position by one of its ends, by the conical washer (45) so as to apply the clamping pressure on the stack.

2. Stack (1) according to the preceding claim, the tie rod (44) passing through the conical washer (45).

3. Stack (1) according to any one of the preceding claims, the conical bearing surface (43) being provided on the face of said clamping plate (23) which is opposite to the stacking.

4. Stack (1) according to any one of the preceding claims, the clamping device comprising a nut (49) screwed onto the tie rod (44) for clamping the conical washer (45) against said clamping plate (23) or the clamping device comprising a compensating member (47) for compensating the dimensional change due to the cells of the stack, the compensating member (47) comprising in particular a spring (47) disposed around the tie rod (44), the compensating member (47) being disposed axially between the conical washer (45) and a limit switch (48), to enable the compensating member (47) to cause a relative displacement of the limit switch (48) with respect to the conical washer (45).

5. Battery (1) according to the preceding claim, the limit switch member (48) having a thread and being screwed onto the tie rod (44).

6. Stack (1) according to any one of the preceding claims, the tie rod (44) being devoid of thermal and / or electrical insulation along the stack.

7. A pile (1) according to any one of the preceding claims, the clamping device comprising, on the side of the other clamping plates (23), a nut (49) screwed onto the tie rod (44) to apply a clamping force to the other clamping plates (23), or a threaded hole formed in the other clamping plates (23) to receive a second of the ends, in particular threaded, of the tie rod (44).

8. Stack (1) according to one of the preceding claims, the other of the clamping plates (23) comprising at least one conical bearing surface (43) opening into a through hole, the clamping device comprising at least two conical washers (45), each washer being received respectively by the conical bearing surface (43) of one and the other of the clamping plates (23), the tie rod (44) being held in position at each of its ends, by the conical washers (45) so as to apply the clamping pressure on the stack.

9. Stack (1) according to any one of the preceding claims, each cell having an opening for the passage of the tie rod (44), the diameter of the opening being strictly greater than the internal diameter of the conical washer (45).