Fuel cell equipped with connection means configured to ensure the monitoring of the elementary cells forming said fuel cell

Abstract

The invention relates to a fuel cell formed from a stack of elementary cells, between which bipolar plates (14) are interposed. Each bipolar plate comprises a connecting pin, called the fixed pin (16), fixed to the bipolar plate and projecting from an edge, called the main edge (15). Together with a housing, called the fixed housing, in which said fixed pin (16) is at least partially housed, the fixed pin forms a connecting plug, called the fixed plug, mechanically fixed to the bipolar plate. The fixed plug is configured to allow for interlocking between the fixed pin (16) and another connecting pin, called the external pin, of an external plug. Figure 4

Description

Title of the invention: Fuel cell equipped with connection means configured to track the elementary cells forming said fuel cell. FIELD OF THE INVENTION

[0001] The invention relates to the field of fuel cells, specifically hydrogen fuel cells. More particularly, the present invention relates to monitoring the health status of the elementary cells of a fuel cell. In particular, the present invention relates to a fuel cell with means for easily and reliably connecting the bipolar plates interposed between the elementary cells of a fuel cell. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] A fuel cell consists of several stacked elementary cells in which an electrochemical reaction takes place between a fuel and an oxidant. An elementary cell includes, in particular, an anode and a cathode, generally planar, between which an electrolytic membrane is interposed.

[0003] The fuel, for example dihydrogen, and the oxidizer, for example air, are introduced gradually as they are consumed. Thus, during operation, the fuel is brought into contact with the anode, while the oxidizer comes into contact with the cathode.

[0004] The electrochemical reaction is then decomposed into two half-reactions called, respectively, the oxidation half-reaction and the reduction half-reaction. More specifically, the oxidation half-reaction occurs at the anode / electrolytic membrane interface, while the reduction half-reaction takes place at the cathode / electrolytic membrane interface.

[0005] Furthermore, the electrolytic membrane, which physically separates the anode from the cathode, exhibits selective permeability. In particular, only certain products of the electrochemical reaction can pass through said membrane while others cannot.

[0006] By way of example, when the fuel comprises hydrogen (H2), and the oxidant comprises air, the oxidation half-reaction can be written as follows:

[0007] H2 H+ + e

[0008] The electrolytic membrane allows H+ ions to pass through, thus enabling them to reach the cathode / electrolytic membrane interface. Once they reach the cathode / electrolytic membrane interface, the H+ ions participate in the reduction of oxygen molecules combine with O2 ions to form water molecules according to the following reduction half-reaction:

[0009] O2 + 4H++ 4e 2H2O

[0010] These water molecules, thus formed in a cathode compartment, are likely, in part, to pass through the electrolytic membrane to reach the anode / electrolytic membrane interface and be released into the anodic compartment. Other species, and in particular nitrogen initially contained in the air supplying the cathode, are likely to migrate through the electrolytic membrane and thus reach the anodic compartment. The presence of these species, particularly water and nitrogen, in the anodic compartment reduces the concentration of dihydrogen in said compartment and affects the performance of the fuel cell.

[0011] The elementary cells are generally separated from each other by bipolar plates configured to allow the distribution of the oxidant and the fuel but also to ensure electrical contact between immediately adjacent anodes and cathodes. Thus, a particular example of a fuel cell is described in document EP 2 207 921 B1 (hereinafter "EP'921").

[0012] In general, the operating status of the individual cells forming the fuel cell must be able to be monitored regularly. To this end, it is generally considered to create contact points at the level of the bipolar plates in order to connect them to measuring means, for example voltage meters, thus allowing regular monitoring of each of the individual cells forming the stack.

[0013] However, the resumption of contact considered remains complicated to implement and does not present the reliability required for long-term monitoring.

[0014] Thus, one object of the present invention is to propose a fuel cell equipped with means for monitoring the health status of the elementary cells forming said cell. BRIEF DESCRIPTION OF THE INVENTION

[0015] The goals of the present invention are achieved by a fuel cell formed of a stack of elementary cells and between which are intercalated bipolar plates, each bipolar plate comprising a connection pin, called fixed pin, fixed to the bipolar plate and projecting with respect to an edge, called main edge, and forming with a housing, called fixed housing, in which said fixed pin is, at least in part, housed, a connection plug, called fixed plug, mechanically fixed to the bipolar plate, the fixed plug being configured to allow cooperation by plugging between the fixed pin and another connection pin, called external pin, of an external plug.

[0016] According to one embodiment, the fixed pin is chosen from one of a male pin and a female pin and the external pin is chosen from the other of the male pin and the female pin.

[0017] According to one embodiment, the fixed pin comprises a first section and a second section, said second section being configured to ensure electrical contact by plugging with the external pin, while the first section is a section by which the fixed pin is held securely to the bipolar plate.

[0018] According to one embodiment, the fixed housing comprises a cavity, called fixed cavity, by a bottom, called fixed bottom, from which the second section is projected.

[0019] According to one embodiment, the bipolar plates are arranged in first plates and second plates, the first plates forming at least one first series and the second plates forming at least one second series, the fixed pins, called first fixed pins, being attached to the first plates of a first series sharing the same fixed housing, called first fixed housing, the fixed pins, called second fixed pins, being attached to the second plates of a second series sharing the same fixed housing, called second fixed housing.

[0020] According to one embodiment, at least a first series and at least a second series are arranged in a periodic arrangement.

[0021] According to one embodiment, the periodic arrangement comprises the repetition of an elementary pattern formed of a first series and a second series.

[0022] According to one embodiment, the periodic arrangement comprises the repetition of another elementary motif formed by the interlacing of a first series and a second series.

[0023] According to one embodiment, the first fixed pins are arranged in a first row and the second pins are arranged in a second row different from the first row.

[0024] According to one embodiment, each fixed housing extends from a rear face to a front face, and is arranged to allow the insertion of at least one fixed pin through its free end through the rear face.

[0025] According to one embodiment, each fixed housing is configured to cooperate with the external plug by snapping it into place. Brief description of the drawings

[0026] Other features and advantages of the invention will become apparent from the detailed description that follows, with reference to the accompanying figures in which:

[0027] [Fig-1] Fig. 1 is a schematic representation of a fuel cell and According to a perspective view, in particular [Fig. 1] represents a stacking, along a stacking direction, formed by an alternation of bipolar plates and elementary cells, said bipolar plates and said elementary cells being essentially planar, and the stacking direction being perpendicular to a principal face of the elementary cells;

[0028] [Fig.2] The [Fig.2] is a schematic representation of an elementary cell that can be implemented in the stacking shown in the [Fig.1], the [Fig.2] also illustrates the reaction processes taking place, respectively, at the anode and the cathode;

[0029] [Fig.3] The [Fig.3] is a simplified and partial representation of a stack of elementary cells and between which bipolar plates are arranged, in particular, the [Fig.3] is a representation according to a perspective view and allowing to observe in part an edge, called principal edge, of each of the bipolar plates;

[0030] [Fig.4] The [Fig.4] reproduces the [Fig.3], the bipolar plates being, on this [Fig.4], equipped with fixed pins;

[0031] [Fig.5] The [Fig.5] is an illustration of an isolated fixed pin 16 and according to a perspective view that can be implemented within the framework of the present invention;

[0032] [Fig.6] The [Fig.6] reproduces the illustration of the [Fig.3], the bipolar plates of this [Fig.6] being equipped with an internal plug;

[0033] [Fig.7] Fig.7 illustrates a fixed plug and an external plug inserted into each other. DETAILED DESCRIPTION OF THE INVENTION

[0034] The invention will be explained with reference to a hydrogen fuel cell, where the anode is supplied with hydrogen and the cathode with air. The fuel cell described in this application includes, in particular, connection means for monitoring, including individual monitoring, of each of the elementary cells (also known as "electrolytic cells"). These means include, in particular, male or female connectors mechanically attached to the bipolar plates interposed between the elementary cells.

[0035] Thus, the invention relates to a fuel cell formed of a stack of elementary cells and between which are intercalated bipolar plates, each bipolar plate comprising a connection pin, called fixed pin, fixed to the bipolar plate and projecting with respect to an edge, called main edge, and forming with a housing, called fixed housing, in which said fixed pin is, at least in part, housed, a connection plug, called fixed plug, mechanically fixed to the bipolar plate, the fixed plug being configured to allow cooperation by plugging between the fixed pin and another connection pin, called external pin, of an external plug.

[0036] It is understood that each fixed pin can be connected, by plugging, to an external pin with a given index corresponding to an index of the fixed pin. The index of a pin (fixed or external) is, in particular, a means of identifying a given fixed pin within the fuel cell. For example, the index of a fixed pin may correspond to its position in the stack of bipolar plates.

[0037] According to the principles of the present invention, the connection of each bipolar plate is achieved by a simple plug-in connection of the outer plug with the inner plug. The inner plug incorporates one or more fixed pins mechanically attached to the bipolar plates. In this respect, each fixed pin is attached to a bipolar plate before the latter is connected (mounted) to an elementary cell of the stack of elementary cells.

[0038] Once the stack is formed, each fixed pin is projected with respect to a principal edge of a bipolar plate, and in particular, without needing to specify it, along a direction of a plane formed by said bipolar plate. The formation of the stack can then involve a subsequent step which comprises the positioning of fixed housings, each fixed housing being adapted to accommodate, at least partially, a fixed pin and so as to form, with said fixed pin, a connection plug, referred to as a fixed plug.

[0039] According to the present invention, a fixed or external housing is an insulating housing, for example made of a polymer material, in particular a plastic material.

[0040] Furthermore, and still according to the present invention, a pin, fixed or external, is made of a conductive material, for example a metal.

[0041] Although primarily designed for hydrogen fuel cells, the invention can be implemented for other types of reactants (oxidizer and / or fuel).

[0042] The general architecture of a hydrogen fuel cell that can be implemented in the present invention is described in document EP'921. In particular, and with reference to [Fig. 1] of the present invention, a hydrogen fuel cell 1 comprises a stack formed by alternating bipolar plates 14 and elementary cells 10. The hydrogen fuel cell also comprises two terminal plates (not shown) between which the stack is intercalated. In particular, and as illustrated in [Fig. 2], an elementary cell 10 comprises an anode 11, a cathode 12, and an electrolytic membrane 13 intercalated between the anode 11 and the cathode 12. The anode 11, the cathode 12, and the electrolytic membrane are generally planar in shape.

[0043] In addition, and without being explicitly mentioned, an elementary cell may also include one or two membranes, in particular membranes allowing the diffusion of reactive species and / or reaction products towards the anode and / or from the cathode.

[0044] These membranes can also be arranged to ensure the sealing of the anodic and / or cathodic compartments.

[0045] It is understood that an anode 11 is in contact with the electrolytic membrane 13 by one of its faces called anode contact face 1 la, and includes a free face, called anode free face 11b opposite to the anode contact face lia.

[0046] It is understood that a cathode 12 is in contact with the electrolytic membrane 13 by one of its faces called cathode contact face 12a, and includes a free face, called cathode free face 12b opposite to the cathode contact face 12a.

[0047] A bipolar plate 14, generally planar, comprises two parallel faces opposite each other and referred to respectively as the anode face 14a and the cathode face 14b.

[0048] Fig. 3 is a simplified and partial representation of a stack of elementary cells and between which bipolar plates 14 are arranged. In particular, Fig. 3 is a representation according to a perspective view and allowing observation in part of an edge, called principal edge 15, of each of the bipolar plates 14. The bipolar plates 14 are in particular arranged so that the principal edges are parallel to each other and belong to the same plane.

[0049] As illustrated in [Fig.4], each bipolar plate 14 includes a connecting pin, called a fixed pin 16, which is integral with the bipolar plate 14 and projected from the main edge 15. In particular, each fixed pin 16 extends parallel to a direction of the plane formed by the bipolar plate 14. More particularly, all the fixed pins 16 can be parallel to each other.

[0050] By way of example, and without limiting the invention to this aspect, each bipolar plate 14 may include a lamella 17, formed in the plane of the bipolar plate and in projection with respect to the main edge 15. In particular, each fixed pin 16 may be mechanically attached to the bipolar plate at the level of the lamella 17.

[0051] Figure 5 is an illustration of an isolated fixed pin 16 in perspective view. In particular, the fixed pin 16 comprises, from a first end to a second end, a first section 16X and a second section 162.

[0052] The fuel cell may also include at least one housing, called fixed housing 18, in which at least one fixed pin 16 is, at least in part, housed, and with which said fixed housing 18 forms a plug, called fixed plug 19.

[0053] In particular, the fixed housing 18 may include a cavity, referred to as the fixed cavity 18i, and a base, referred to as the fixed base 182, from which the second section is projected. Specifically, the first section 16i of the fixed pin 16 may be encapsulated within the volume of the fixed housing 18, and the second section 162 may be projected relative to the fixed base section 182.

[0054] The fixed plug 19, mechanically attached to at least one bipolar plate 14, is configured to allow cooperation by plugging between the fixed pin 16 and another connection pin, called external pin, of an external plug 20.

[0055] Figure 7 illustrates in this regard a fixed plug 19 and an external plug 20 inserted into each other. In this regard, the fixed housing 19 is configured to cooperate with the external plug 20 by snapping it into place.

[0056] By way of further example, each fixed housing 18 can generally be rectangular in shape. In particular, each housing 18 can extend from a rear face 21 to a front face 22, and is arranged to allow the insertion of at least one fixed pin 16 through its free end via the rear face.

[0057] Thus, a fixed pin 16 can be mechanically secured to a bipolar plate by its first section 16i. In particular, the fixed pin can be secured to the bipolar plate by crimping, welding, or brazing. Advantageously, the fixed pin can be pre-formed with the bipolar plate in question.

[0058] The second section, defined in relation to [Fig.5], can be configured to ensure electrical contact by plugging with the external pin.

[0059] According to an advantageous embodiment, the bipolar plates 14 can be arranged in first plates and second plates, the first plates forming at least one first series (for example, 4 bipolar plates) and the second plates forming at least one second series (for example, 4 bipolar plates). The fixed pins, referred to as first fixed pins, attached to the first plates of a first series share the same fixed housing, referred to as the first fixed housing; the fixed pins, referred to as the second fixed pins, attached to the second plates of a second series share the same fixed housing, referred to as the second fixed housing.

[0060] As a reminder, a bipolar plate is an assembly of two polar plates called, respectively, cathode plate and anode plate.

[0061] Within the framework of the present invention, a first bipolar plate and a second bipolar plate may differ only in the type of anode plate. In other words, a first bipolar plate and a second bipolar plate may each comprise a cathode plate having the same characteristics.

[0062] Advantageously, the fixed boches are formed on the anode plates.

[0063] Always this advantageous embodiment, at least a first series and the minus a second series are arranged periodically.

[0064] According to a first alternative of this advantageous embodiment, the periodic arrangement may include the repetition of an elementary pattern formed of a first series and a second series.

[0065] According to a second alternative of this advantageous embodiment, the periodic arrangement may comprise the repetition of another elementary motif formed by the interlacing of a first series and a second series. The interlacing thus results in the repetition of an elementary motif formed by a first plate and a second plate.

[0066] Advantageously, the first fixed pins are arranged in a first row and the second pins are arranged in a second row different from the first row.

[0067] It is thus understood that the fixed connector can be formed for a plurality of fixed pins and a fixed housing. Furthermore, among all the fixed connectors, a distinction can be made between first fixed connectors and second fixed connectors. In particular, a first fixed connector can be associated with a first series (specifically, the first 4 plates) while a second fixed connector can be associated with a second series (specifically, the second 4 plates).

[0068] Consideration of the plugs as described in the present invention not only makes it easier and more reliable to connect the bipolar plates for monitoring the state of the elementary cells, but also allows for a reduced spacing between said bipolar plates, in particular less than 2 mm, advantageously less than 1.5 mm, even more advantageously less than 1 mm.

[0069] Of course, the invention is not limited to the embodiments described and alternative embodiments can be made without departing from the scope of the invention as defined by the claims.

Claims

Demands

1. Fuel cell (1) formed of a stack of elementary cells (10) and between which are intercalated bipolar plates (14), each bipolar plate comprising a connection pin, called fixed pin (16), fixed to the bipolar plate and projecting from an edge, called main edge (15), and forming with a housing, called fixed housing (18), in which said fixed pin (16) is, at least in part, housed, a connection plug, called fixed plug (19), mechanically fixed to the bipolar plate, the fixed plug (19) being configured to allow cooperation by plugging between the fixed pin (16) and another connection pin, called external pin, of an external plug (20).

2. Fuel cell (1) according to claim 1, wherein the fixed pin (16) is selected from one of a male pin and a female pin and the external pin is selected from the other of the male pin and the female pin.

3. Fuel cell (1) according to claim 1 or 2, wherein the fixed pin (16) comprises a first section (16X) and a second section, said second section (162) being configured to ensure electrical contact by plugging with the external pin, while the first section (16i) is a section by which the fixed pin (16) is held securely to the bipolar plate.

4. Fuel cell (1) according to claim 3, in which the fixed casing (18) comprises a cavity, referred to as fixed cavity (18i), by a bottom, referred to as fixed bottom, from which the second section (162) is projected.

5. Fuel cell (1) according to any one of claims 1 to 4, wherein the bipolar plates (14) are arranged in first plates and second plates, the first plates forming at least a first series and the second plates forming at least a second series, the fixed pins, referred to as first fixed pins, being integral with the first plates of a first series sharing the same fixed housing, referred to as first fixed housing (18), the fixed pins, referred to as second fixed pins, being integral with the second plates of a second series sharing the same fixed housing, referred to as second fixed housing (18).

6. Fuel cell (1) according to claim 5, wherein at least a first series and at least a second series are arranged in a periodic arrangement.

7. Fuel cell (1) according to claim 6, wherein the periodic arrangement comprises the repetition of an elementary pattern formed of a first series and a second series.

8. Fuel cell (1) according to claim 6, wherein the periodic arrangement comprises the repetition of another elementary pattern formed by the interlacing of a first series and a second series.

9. Fuel cell (1) according to claim 6 or 8, wherein the first fixed pins are arranged in a first line and the second pins are arranged in a second line different from the first line.

10. Fuel cell (1) according to any one of claims 1 to 9, wherein each fixed housing (18) extends from a rear face (21) to a front face (22), and is arranged to permit the insertion of at least one fixed pin (16) through its free end through the rear face (21).

11. Fuel cell (1) according to any one of claims 1 to 10, wherein each fixed housing (18) is configured to cooperate with the external plug (20) by snapping.

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