FUEL CELL

Description

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

[0002] The stack of such a battery is sandwiched between two clamping plates to apply a determined clamping pressure to the stack, at least one end of the stack comprising an electrically conductive current collector plate electrically connected to the cells of the stack to collect the sum of the electrical currents produced by the cells.

[0003] Such compression of the cell stack is often detrimental not only to battery performance, but also to their lifespan. Indeed, an insufficiently compressed area has increased electrical contact resistance compared to a more compressed area. An insufficiently compressed area therefore has degraded operation due to higher ohmic losses. Conversely, a cell area that is relatively overcompressed undergoes accelerated mechanical degradation.

[0004] Furthermore, at least one of the ends of the stack includes piping for the circulation of reactive fluids (air or hydrogen) and for the circulation of the cooling fluid (often a liquid).

[0005] Therefore, it is important to properly seal at least the interface located at the end of the stack containing the piping for the circulation of fluids, in particular between the clamping plate and the electric current collector plate.

[0006] Known solutions often use a plurality of O-rings arranged on either side of the electric current collector plate. This type of solution is complex to implement and there remains a high risk of leaks, linked to the compression of the stack at the level of the passage zones of the different fluids. US 6372372B1 and US 2005 / 095485A1 can be cited as representative prior art.

[0007] The present invention aims to effectively overcome these drawbacks by proposing a fuel cell, comprising a stack of a plurality of cells, the stack being sandwiched between a first clamping plate and a second clamping plate, for applying a predetermined clamping pressure to the stack, the plurality of cells comprising 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 anode plate and a cathode plate, one of the plates of the first cell forming with one of the plates of another of the cells, a first intercellular 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 intercellular cooling circuit,the other of the plates of the last cell defining a last end plate, the cell comprising a distribution plate comprising a first electric current collection face intended to face a first electric current collector plate and a distribution face intended to face the cooling face of the first end plate, the cell comprising a first flat seal interposed between the distribution plate and the first clamping plate, the distribution plate comprising at least one distribution collector of a fluid formed through the plate, the first electric current collection face and / or the first clamping plate comprising an annular lip arranged around the distribution collector, so as to pinch the first flat seal to ensure a seal against the fluid.,

[0008] Such a configuration ensures correct sealing against the fluid, the flat seal being pinched locally at the distribution manifold.

[0009] According to one embodiment, the fuel cell is a proton exchange membrane fuel cell.

[0010] According to one embodiment, the anode plate and the cathode plate of each cell sandwich a Membrane Electrode Assembly.

[0011] According to one embodiment, the distribution plate is fixed to the first end plate, in particular by welding.

[0012] Alternatively, the distribution plate and the first end plate form a single part manufactured by molding, and / or machining and / or hydroforming and / or stamping and / or three-dimensional printing.

[0013] Such a fixing ensures better sealing against the fluid.

[0014] 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 in the first cell.

[0015] According to one embodiment, the distribution plate comprises six distribution manifolds, in particular for distributing or collecting fuel, an oxidizer and a cooling fluid.

[0016] According to one embodiment, the annular lip is provided around the entire circumference of the distribution manifold.

[0017] According to one embodiment, the annular lip projects relative to the plane of the plate.

[0018] According to one embodiment, the annular lip is made from the material of the first clamping plate.

[0019] Alternatively, the annular lip is made from the material of the distribution plate.

[0020] According to one embodiment, one of the first electric current collection face and the first clamping plate comprises an annular lip arranged around the distribution manifold and the other of the first electric current collection face and the first clamping plate comprises an annular groove, so as to pinch the first flat seal to ensure a seal against the fluid.

[0021] According to one embodiment, the annular groove and the annular lip are arranged so that the lip is opposite the groove in the absence of the flat seal.

[0022] This arrangement allows the flat seal to be pinched, forming two folds on it.

[0023] According to one embodiment, the first flat seal has, at rest, a substantially constant thickness over its entire surface.

[0024] According to one embodiment, the first flat seal has no boss.

[0025] According to one embodiment, the first flat seal has a flat face whose surface area is at least equal to 80% of the surface area of ​​the face of the first end plate opposite the first flat seal.

[0026] According to one embodiment, the first flat seal has a flat face whose surface area is at least equal to 80% of the surface area of ​​the face of the first clamping plate.

[0027] According to one embodiment, the first flat seal is electrically insulating.

[0028] According to one embodiment, the first flat seal comprises a material based on silicone, elastomer or ethylene-propylene-diene monomer (EPDM).

[0029] According to one embodiment, the first flat seal is in contact with at least a portion of the first collector plate and is in contact with at least a portion of the distribution plate.

[0030] According to one embodiment, the battery is without an O-ring placed on either side of the first flat seal, to ensure sealing against the fluid.

[0031] According to one embodiment, the first electric current collection face comprises a first embossment for receiving the first collector plate, so that the distribution plate and the first collector plate together form a flat face for coming into contact with the first flat seal.

[0032] According to one embodiment, the first flat seal comprises at least one orifice for the passage of fluid between the first clamping plate and the distribution plate.

[0033] According to one embodiment, the first collector plate comprises a tab projecting relative to the plane of the first collector plate and the first flat seal comprises a slot for the passage of the tab through the first flat seal.

[0034] According to one embodiment, the slot is distinct from the orifice.

[0035] According to one embodiment, the stack comprises at least one tie rod for applying the clamping pressure to the stack.

[0036] According to one embodiment, the first flat seal comprises at least one through hole for the passage of the tie rod.

[0037] According to one embodiment, the first collector plate is electrically connected to the distribution plate.

[0038] According to one embodiment, each anode or cathode plate comprises a reactive face and a cooling face opposite one another, the reactive face 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 anode plate of another of the cells, defining between them reliefs and hollows to form an intercellular cooling circuit for the circulation of a cooling fluid.

[0039] According to one embodiment, each cathode or anodic plate comprises a reagent inlet manifold formed through the plate and being in fluid communication with the reagent circuit, a reagent outlet manifold formed through the plate and being in fluid communication with the reagent circuit, a cooling fluid inlet manifold formed through the plate, a cooling fluid outlet manifold formed through the plate.

[0040] According to one embodiment, the cell comprises a closure plate comprising a second electric current collection face intended to face a second electric current collector plate and a closure face fixed to the cooling face of the last end plate, the closure face and the cooling face of the last end plate defining between them reliefs and hollows to form a last cooling circuit for the circulation of the cooling fluid.

[0041] According to one embodiment, the battery comprises a second flat seal interposed between the second collector plate and the second clamping plate.

[0042] According to one embodiment, the second flat seal has, at rest, a constant thickness over its entire surface.

[0043] According to one embodiment, the second flat seal is electrically insulating.

[0044] According to one embodiment, the second flat seal has a flat face whose surface is at least equal to 80% of the surface of one of the faces of the second clamping plate.

[0045] According to one embodiment, the second flat seal has a flat face whose surface is at least equal to 80% of the surface of one of the faces of the closure plate.

[0046] According to one embodiment, the second electric current collection face comprises a second embossment for receiving the second collector plate, so that the closure plate and the second collector plate form a flat face for coming into contact with the second flat seal.

[0047] The invention will be better understood by reading the following description and examining the figures. These figures are given only for illustrative purposes but in no way limit the invention. [ Fig.1 ] There [ Fig.1 ] is a schematic cross-sectional representation of a battery according to the invention; and [ Fig.2 ] there [ Fig.2 ] is a schematic elevation representation of the stack of the [ Fig.1 ].

[0048] Identical, similar, or analogous elements retain the same reference from one figure to another.

[0049] As visible on the [ Fig.1 ], a proton exchange membrane fuel cell 1 comprises comprising a stack of a plurality of cells 30, the stack being sandwiched between a first clamping plate 17, 23 and a second clamping plate 22, for applying a predetermined clamping pressure to the stack.

[0050] 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.

[0051] Each cell 30 of the plurality comprises an anode plate 10 and a cathode 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 intercellular 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 intercellular cooling circuit 15, the other of the plates 10, 20 of the last cell 30 defining a last end plate.

[0052] The battery 1 comprises a distribution plate 11 comprising a first electric current collection face intended to face a first electric current collector plate 24 and a distribution face intended to face the cooling face of the first end plate.

[0053] The battery 1 comprises a first flat seal 19 interposed between the distribution plate 11 and the first clamping plate 17, 23, the distribution plate 11 comprising 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 comprising an annular lip arranged around the distribution collector, so as to pinch the first flat seal 19 to ensure a seal against the fluid.

[0054] The first electric current collecting face has a first embossment for receiving the first collector plate 24, so that the distribution plate 11 and the first collector plate 24 together form a flat face for coming into contact with the first flat gasket 19.

[0055] The first flat seal 19 comprises at least one orifice for the passage of fluid between the first clamping plate 17, 23 and the distribution plate 11.

[0056] The first collector plate 24 comprises a tab projecting relative to the plane of the first collector plate 24.

[0057] The first flat seal 19 has a slot for the passage of the tab through the first flat seal 19.

[0058] The stack has at least one tie rod to apply clamping pressure to the stack.

[0059] The first flat seal 19 has at least one through hole for the passage of the tie rod.

[0060] As visible on the [ Fig.1 ], the cell 1 comprises a closure plate 21 comprising a second electric current collection face intended to face a second electric current collector plate 25 and a closure face fixed to the cooling face of the last end plate, the closure face and the cooling face of the last end plate defining between them reliefs and hollows to form a last cooling circuit for the circulation of the cooling fluid.

[0061] The battery 1 comprises a second flat seal 18 interposed between the second collector plate 25 and the second clamping plate 22.

[0062] There [ Fig.2 ] represents stack 1 in elevation, before assembly.

[0063] As visible on the [ Fig.2 ], each plate 10, 20 comprises: a reagent inlet manifold 3, 4 formed through the plate 10, 20 and being in fluid communication with the reagent circuit via a first lumen 2 formed through the plate 10, 20; a reagent outlet manifold 6, 7 formed through the plate 10, 20 and being in fluid communication with the reagent circuit via a second lumen 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 fluid communication only through the plate 10, 20, without being in fluid communication with the reagent circuit.

[0064] The reagent inlet manifold 3 of an anode plate 10 is in fluid communication with one of the ports of a cathode plate 20 and the reagent outlet manifold 6 of the anode plate 10 is in fluid communication with another of the ports of the cathode plate 20.

[0065] The reagent inlet manifold 3 of a cathode plate 20 is in fluid communication with one of the ports of an anode plate 10 and the reagent outlet manifold 6 of the cathode plate 20 is in fluid communication with another of the ports of the anode plate 10.

[0066] Thus, the stack allows distribution of the reactive fluid dedicated to the anode plates 10 and distribution of the reactive fluid dedicated to the cathode plates 20 by forming two independent circuits.

[0067] The closure face of the closure plate 21 comprises a reagent passage 12, 13 formed by reliefs and hollows, to allow fluid communication between the reagent inlet manifold 3, 4 and the reagent circuit or to allow fluid communication between the reagent outlet manifold 6, 7 and the reagent circuit.

[0068] The closure face of the closure plate 21 comprises 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.

[0069] The reagent passage 12, 13 and the cooling passage 13 may be provided at the closure face, at the last end plate or on both.

Claims

1. Fuel cell (1) having a stack of a plurality of cells (30), the stack being sandwiched between a first clamping plate (17, 23) and a second clamping plate (22) to apply a predetermined clamping pressure to the stack, the plurality of cells (30) having a first cell (30) at a first end of the stack and a last cell (30) at a second end of the stack, each cell (30) of the plurality having an anode plate (10) and a cathode plate (20), 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, the fuel cell (1) having 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, the fuel cell (1) having a first flat seal (19) interposed between the distribution plate (11) and the first clamping plate (17, 23), the distribution plate (11) having at least one fluid distribution manifold formed through the plate, the first electric current collection face and / or the first clamping plate (17, 23) having an annular lip formed about the distribution manifold so as to clamp the first flat seal (19) to provide a fluidtight seal.

2. Fuel cell (1) according to the preceding claim, the first flat seal (19) having, when unstressed, a substantially constant thickness over the entire surface thereof.

3. Fuel cell (1) according to one of the preceding claims, the first flat seal (19) having a flat face, the surface of which is at least equal to 80% of the surface of the face of the first end plate facing the first flat seal (19).

4. Fuel cell (1) according to one of the preceding claims, the first flat seal (19) being electrically insulating.

5. Fuel cell (1) according to one of the preceding claims, the first flat seal (19) being in contact with at least a portion of the first collection plate (24) and being in contact with at least a portion of the distribution plate (11).

6. Fuel cell (1) according to one of the preceding claims, the fuel cell not having an O-ring arranged on either side of the first flat seal (19) to provide a fluidtight seal.

7. Fuel cell (1) according to one of the preceding claims, the first electric current collection face having a first boss for receiving the first collection plate (24), such that the distribution plate (11) and the first collection plate (24) together form a flat face to come into contact with the first flat seal (19).

8. Fuel cell (1) according to one of the preceding claims, the first flat seal (19) having at least one orifice to enable the fluid to pass between the first clamping plate (17, 23) and the distribution plate (11).

9. Fuel cell (1) according to one of the preceding claims, the first collection plate (24) having a tongue projecting from the plane of the first collection plate (24) and the first flat seal (19) having a slot enabling the tongue to pass through the first flat seal (19).

10. Fuel cell (1) according to one of the preceding claims, the fuel cell having at least one tie rod for applying the clamping pressure to the stack, the first flat seal (19) having at least one through-hole for passage of the tie rod.