Assembly for a fuel cell

Abstract

Disclosed is an assembly for a fuel cell, comprising: - a fuel cell (11) comprising at least two bipolar plates (13), and - a base connector (21), characterized in that each bipolar plate (13) comprises at least one contact-receiving area (18), - the base connector (21) comprising a body (22) made of an electrically insulating material and at least two base contacts (23), each base contact (23) being inserted inside a through-opening (26) made in the body (22), each base contact (23) having a split end (27) intended to locally establish contact by clamping with the contact-receiving area (18) of a corresponding bipolar plate (13) so as to ensure an electrical connection between the base contact (23) and the corresponding bipolar plate (13), the split end (27) of the base contact (23) comprising a slot inside which a protrusion (17) of a bipolar plate (13) is inserted.

Description

DESCRIPTION TITLE: FUEL CELL KIT

[0001] The present invention relates to an assembly for a fuel cell. The invention finds a particularly advantageous, but not exclusive, application with fuel cells used to power electrical components, such as electric motors, in transport vehicles, such as automobiles or aircraft.

[0002] As is well known, a fuel cell, as described in document EP1528614, produces electrical energy from an electrochemical reaction between different fluids. Typically, a fuel cell is powered by hydrogen and oxygen, which react within the cell to generate electrical energy. A fuel cell consists of a stack of several cells aligned along a stacking axis. This stack of cells enables the electrochemical reaction with the fluids.

[0003] Each cell comprises an ion-conducting electrolyte surrounded by two electrodes, which are themselves surrounded by interconnecting plates. For example, in a proton exchange membrane fuel cell (PEMFC), the electrolyte is a proton-conducting polymer membrane, and the electrodes are a porous medium containing a catalyst such as platinum. The electrolyte and electrode assembly is called a Membrane Electrode Assembly (MEA). Each MEA is brought into contact with reactive gases on its two opposite faces (for example, hydrogen and oxygen, possibly from the air) via the interconnecting plates to form a cell.

[0004] The assembly of two interconnecting plates, belonging to two adjacent cells, is called a bipolar plate. Thus, a bipolar plate... A bipolar plate is located between the cathode of one AME and the anode of the adjacent AME. It supplies fuel (hydrogen) to a first AME on the anodic side and oxidizer (oxygen) to a second AME on the cathodic side. Generally, each bipolar plate has an internal cooling circuit through which a heat transfer fluid circulates to either supply heat or remove heat produced by the exothermic reaction.

[0005] The current generated by the cells is collected at both ends of the stack by conductive plates called collectors. The electrical power delivered by the fuel cell depends on the number of cells (voltage capacity delivered) and the active surface area of ​​the cells (current capacity delivered).

[0006] The entire cell stack is held in compression between two end plates connected by a compression support system that maintains and ensures the stack's airtightness. This airtightness is achieved through gaskets inserted between the bipolar plates and the cell membranes (MMs). The end plates are typically massive because they must apply uniform pressure to the cell surface and remain dimensionally stable under the effects of the stack's internal pressure and temperature variations.

[0007] The cell voltage can be measured via male contacts that fit into slots provided in the bipolar plates, as described in document EP3284127. These slots are created in the plane of the bipolar plates by a specific shaping of the two metal sheets constituting the bipolar plates to create an insertion hole. An electrical wire is crimped to the back of these male contacts. All the electrical wires are bundled together in a main electrical harness. Another technique involves soldering a contact directly onto the bipolar plate.

[0008] However, the contact insertion or soldering operations are time-consuming because they are performed on each of the bipolar plates. The wires are taken from a main harness and cut to individual lengths. There is also a significant risk of contact reversal during this installation, as well as a risk of deformation of the bipolar plates at the contact insertion holes.

[0009] The invention aims to effectively remedy the aforementioned drawbacks by proposing an assembly for a fuel cell comprising: - a fuel cell comprising at least two bipolar plates, each bipolar plate comprising at least one contact receiving area, and - a base connector comprising at least two base contacts, each base contact having a slotted end intended to establish local contact by pinching with the contact reception area of ​​a corresponding bipolar plate so as to ensure an electrical connection between the base contact and the corresponding bipolar plate.

[0010] The invention thus proposes a connector system for voltage measurement points on fuel cells that is quick and easy to install on the bipolar plates of the fuel cell. The invention can also be easily adapted to different fuel cell sizes. Furthermore, the invention offers the advantage of a compact design and ensures reliable voltage measurements at the fuel cell terminals.

[0011] According to one embodiment of the invention, a contact reception area is constituted by an outgrowth made in an edge of the bipolar plate.

[0012] According to one embodiment of the invention, the base connector comprises at least one bipolar plate separation guide intended to be inserted between two consecutive bipolar plates.

[0013] According to one embodiment of the invention, the base connector comprises at least two separation guides arranged on either side of a base contact, such that a portion of each separation guide covers a portion of the base contact to prevent a short circuit between the bipolar plate to which the base contact is connected and an adjacent bipolar plate.

[0014] According to one embodiment of the invention, the base connector comprises a plurality of base contacts arranged in at least one row of contacts, two adjacent base contacts being separated from each other in a longitudinal extension direction of an edge of a bipolar plate and in a vertical direction by a distance corresponding to a gap between two consecutive bipolar plates.

[0015] According to one embodiment of the invention, the base contacts are arranged in two rows of contacts parallel to each other.

[0016] According to one embodiment of the invention, the base connector has two lateral lugs intended to cooperate with a retaining frame to hold the base connector on the fuel cell.

[0017] According to one embodiment of the invention, the support frame is fixed to the terminal plates of the fuel cell.

[0018] According to one embodiment of the invention, said assembly further comprises a movable connector having at least two movable contacts intended to establish an electrical connection with the base contacts.

[0019] According to one embodiment of the invention, the movable contacts each have an end disposed inside a portion chosen from a male portion or a female portion which is inserted on the front face inside another complementary portion chosen from a male portion or a female portion of the base connector disposed on the rear face of the base connector so as to establish electrical continuity to the bipolar plates.

[0020] According to one embodiment of the invention, the movable contacts of the movable connector include means for connection with electrical wires intended to be electrically connected to a voltage acquisition system.

[0021] According to one embodiment of the invention, the mobile connector includes at least one locking element intended to cooperate with a locking element of complementary shape made in the mobile connector so as to allow the mobile connector to be locked onto the base connector.

[0022] According to one embodiment of the invention, the base connector and the mobile connector include keying means to prevent reverse mounting between the mobile connector and the base connector.

[0023] According to one embodiment of the invention, said assembly includes at least one electrical insulation cover that can replace the base connector.

[0024] According to one embodiment of the invention, the electrical insulation cover includes separation guides to prevent any contact between the bipolar plates.

[0025] According to one embodiment of the invention, the base connector includes a rear fitting ensuring the retention of an electrical harness.

[0026] The present invention will be better understood and other features and advantages will become apparent upon reading the following detailed description, which includes embodiments given by way of illustration with reference to the accompanying figures, presented by way of non-limiting examples, which may serve to complete the understanding of the present invention and the explanation of its implementation and, where appropriate, contribute to its definition, on which:

[0027] [Fig. 1] Figure 1 is a schematic representation of a stack of two cells of a fuel cell according to the present invention;

[0028] [Fig. 2] Figure 2 is a side perspective view of the bipolar plates of a fuel cell equipped with protrusions intended to cooperate with a base connector according to the invention;

[0029] [Fig. 3] Figure 3 is a perspective view of a base connector according to the invention intended to be electrically connected with the bipolar plates and of a movable connector according to the invention intended to cooperate with the base connector according to the invention;

[0030] [Fig. 4] Figure 4 is a cross-sectional view of the interconnection between the base connector and the bipolar plates as well as between the mobile connector and the base connector according to the invention;

[0031] [Fig. 5] Figure 5 is a perspective view illustrating the retention of a set of base connectors against the fuel cell by means of a retaining frame according to the invention;

[0032] [Fig. 6] Figure 6 is a perspective view of an insulation cover according to the invention that can be substituted for a base connector according to the invention;

[0033] [Fig. 7] Figure 7 is a perspective view illustrating the retention of a set of insulation covers of Figure 6 against the fuel cell by means of a retaining frame according to the invention;

[0034] [Fig. 8] Figure 8 is a perspective view of a support frame pre-equipped with a set of base connectors according to the invention;

[0035] [Fig. 9a] [Fig. 9b] Figures 9a and 9b are perspective and partial section views of an embodiment variant of a base connector according to the invention and of a movable connector according to the invention.

[0036] It should be noted that structural and / or functional elements common to the different embodiments may have the same references. Thus, unless otherwise specified, such elements have identical structural, dimensional, and material properties.

[0037] By convention in the following description, the "front face" of an element is the face of that element that is opposite the bipolar plates, and the "rear face" is the face of that element facing in the opposite direction to the bipolar plates. In other words, the observer of this element views the element from the bipolar plates of the fuel cell.

[0038] Figure 1 schematically illustrates a stack of two cells 10 of a fuel cell 11. The fuel cell 11 may consist of a single cell 10 or a plurality of cells 10. Each cell 10 comprises a Membrane Electrode Assembly (MEA) 12, two bipolar plates 13, and two sealing gaskets 15. One bipolar plate 13 is common to two adjacent cells 10. A voltage measurement is taken across the cells 10, between the bipolar plates 13, to monitor the fuel cell's health.

[0039] As illustrated in Figure 2, the bipolar plates 13 have protrusions 17 forming contact reception areas 18 for the base contacts 23, as explained in more detail below. Each protrusion 17 is formed in an edge of a corresponding bipolar plate 13. A protrusion 17 extends in the plane of the bipolar plate 13 and projects beyond the rest of the edge of the bipolar plate 13. The protrusion 17 has a length approximately equal to the width of a base connector 21 described below. This allows for standardization in the manufacture of the bipolar plates 13, which are identical to one another.

[0040] As can be seen in Figures 3 and 4, the base connector 21 is designed to establish an electrical connection with the bipolar plates 13. More specifically, the base connector 21 comprises a body 22 made of an electrically insulating material. The body 22 has a trapezoidal cross-section and is compatible with other base connectors 21. Alternatively, the body 22 may have a rectangular cross-section or any other shape suitable for the application.

[0041] The base connector 21 comprises a plurality of base contacts 23 made of an electrically conductive material, in particular copper or aluminum, or an alloy based on at least one of these materials. Each base contact 23 is inserted into a through-hole 26 formed in the body 22. Each base contact 23 passes through the base connector 21 on both sides so as to be accessible from both sides of the base connector 21.

[0042] The base contacts 23 are advantageously arranged in at least one row of contacts R1, R2. Two adjacent base contacts 23 are separated from each other along a longitudinal extension direction L1 of a protrusion 17, or of an edge of a bipolar plate 13, and along a vertical direction L2 by a distance corresponding to the gap between two consecutive bipolar plates 13. In this case, the base contacts 23 are arranged in two rows of contacts R1, R2 parallel to each other.

[0043] As illustrated in Figure 4, on one front face of the connector base 21, a contact base 23 has a slotted end 27 for establishing local contact by pinching with a corresponding contact receiving area 18, here a protrusion 17, so as to ensure an electrical connection between a contact base 23 and a corresponding bipolar plate 13. A contact base 23 is shaped like a pin with a slotted end. One end 27 of the contact base 23 thus has a slot into which a protrusion 17 of a bipolar plate 13 is inserted. The slotted end 27 may be cylindrical and have a slot with a width slightly less than or equal to the thickness of a bipolar plate 13.

[0044] On one rear face of the base connector 21, a base contact 23 has a solid, tubular end 28 designed to cooperate with a housing for a contact of the mobile connector 41 described in more detail below. Preferably, the solid end 28 is located inside a female portion 29 of the base connector 21 designed to cooperate with a corresponding male portion 48 of the mobile connector 41.

[0045] Preferably, the base connector 21 includes separation guides 32 for the bipolar plates 13. A separation guide 32 is designed to be inserted between two adjacent bipolar plates 13. The separation guides 32 facilitate the connection of the base contacts 23 to the bipolar plates 13 during the assembly of the base connector 21 onto the fuel cell 11. The separation guides 32 are more clearly visible in Figure 6 under reference numeral 60 when integrated into an electrical insulation cover 56.

[0046] Two separation guides 32 are arranged on either side of a corresponding base contact 23, such that a portion of each separation guide 32 covers a portion of the base contact 23 to prevent a short circuit between the bipolar plate 13 to which the base contact 23 is connected and an adjacent bipolar plate 13. The separation guides 32 are consisting of walls made of material with a front face of the body 22 of the base connector 21. The walls 32 extend in a plane parallel to a plane in which a bipolar plate 13 extends.

[0047] The base connector 21 may also include two lateral lugs 33 for cooperating with a retaining frame 35, visible in Figure 5, to retain the base connector 21 on the fuel cell 11. The lateral lugs 33 extend laterally from the body 22 of the base connector 21. Each lateral lug 33 has a groove for receiving a vertical lateral flank 39 of the retaining frame 35. Each lateral lug 33 has a wall 34.1 extending laterally from a corresponding lateral face of the base connector 21 and a wall 34.2 extending parallel to the corresponding lateral face of the base connector 21. The wall 34.1 can form a right angle with the side face or, as shown, a top angle so that a side lug 33 has a V-shape. The side lugs 33 are arranged on the side of a front face of the base connector 21.

[0048] As illustrated in Figure 5, the base connector 21 is held by two lateral sides 39 of the retaining frame 35, each inserted into a groove in a corresponding lateral lug 33. The lateral sides can press the lateral lugs 33 of the base connector 21 against the fuel cell 11. The lateral sides 39 extend vertically along a stacking axis of the cells 10 of the fuel cell 11.

[0049] The retaining frame 35 is fixed to the end plates 36 of the fuel cell 11. For this purpose, the retaining frame 35 comprises an upper portion 37 and a lower portion (not shown) connecting the two lateral sides 39. The upper and lower portions 37 extend longitudinally parallel to a plane in which a bipolar plate 13 extends. Each upper and lower portion 37 comprises means 38 for fixing the retaining frame 35 to the end plates 36 of the fuel cell 11. The fixing means 38 comprise, for example, a screw inserted inside a fixing hole made in the upper portion 37 (respectively the lower portion of the retaining frame 35).

[0050] The retaining frame 35 ensures the retention and alignment of several base connectors 21 positioned one below the other, as well as the retention of the slotted base contacts 23 on the protrusions 17 of the bipolar plates 13. The retaining frame 35 can also allow the routing and attachment of electrical wires in a single electrical harness.

[0051] The base connectors 21 are not vertically blocked and can therefore slide along the lateral sides 39 of the retaining frame 35. The retention of the base connectors 21 by means of the retaining frame 35 thus allows the relative movement of the base connectors 21 with respect to each other during the thermal expansion of the stack of cells 10 without risk of breakage of the various base contacts 23.

[0052] Furthermore, as can be seen in Figures 3 and 4, a movable connector 41 comprises a body 42 made of an electrically insulating material. The body 42 has a shape similar to that of the base connector 21, in particular a trapezoidal cross-section. Alternatively, the body 42 may have a rectangular cross-section or any other shape suitable for the application.

[0053] The mobile connector 41 comprises a plurality of movable contacts 43 for establishing an electrical connection with the base contacts 23. A "moving" contact is understood to be a contact associated with the mobile connector 41. A movable contact 43 may, however, be fixed within the body 42 of the mobile connector 41. The movable contacts 43 are made of an electrically conductive material. Each movable contact 43 is inserted into a through-hole 44 in the body 42. The movable contacts 43 are preferably standard, normalized contacts. The movable contacts 43 are arranged in a manner corresponding to that of the base contacts 23, in this case, in two rows of contacts.

[0054] On the front side of the mobile connector 41, the mobile contacts 43 each have an end 47 arranged inside a male portion 48 fitting into a corresponding female portion 29 of the base connector 21 arranged on the rear face of the base connector 21 so as to establish electrical continuity to the bipolar plates 13 of the fuel cell 11. Alternatively, the configuration can be reversed, i.e. the male portion 48 is made in the base connector 21 and the female portion is made in the movable connector 41.

[0055] On the rear face of the mobile connector 41, the moving contacts 43 have means 49 for connecting electrical wires intended to be electrically connected to a voltage acquisition system, as shown in Figure 4. More specifically, each moving contact 43 has an end equipped with a means 49 for connecting an electrical wire. The connection means 49 may be in the form of crimping or soldering means for establishing a permanent electrical connection between the electrical wires and the moving contacts 43. The electrical wires are bundled together to form an electrical harness 52 (see Figure 5).

[0056] The mobile connector 41 includes at least one locking element 53 intended to cooperate with a locking element 54 of complementary shape made in the base connector 21 so as to allow the mobile connector 41 to be locked onto the base connector 21, as shown in Figure 3. The locking element 53 of the mobile connector 41 may be in the form of a snap-on tab intended to cooperate with a correspondingly shaped receiving slot 54 made in the base connector 21. Alternatively, the configuration may be reversed, i.e. the snap-on tab 53 may be carried by the base connector 21 while the receiving slot 54 is provided in the mobile connector 41.

[0057] The base connector 21 and the mobile connector 41 have keying means 55 to prevent reversed assembly between the mobile connector 41 and the base connector 21. In particular, the keying means 55 consist of the two rows of contacts R1, R2 of the base connector 21 (and therefore of the mobile connector 41) having a different number of electrical contacts to prevent incorrect assembly of the connector in the event that it is rotated 180 degrees from its position of use.

[0058] As illustrated in Figure 6, an electrical insulation cover 56 can be substituted for a base connector 21 when the latter is not in use. For this purpose, the electrical insulation cover 56 comprises an insulating body 57 having a shape similar to that of the body 22 of the base connector 21. The electrical insulation cover 56 also comprises lateral tabs 58 similar to those of the base connector 21.

[0059] The electrical insulation cover 56 may have on its front face separation guides 60 intended to be inserted each between two adjacent bipolar plates 13 in order to avoid any contact between the bipolar plates 13. The separation guides 60 have a configuration analogous to that of the separation guides 32 of the base connector 21.

[0060] As illustrated in Figure 7, the electrical insulation covers 56 positioned one below the other can be held by the retaining frame 35 in place of the base connectors 21.

[0061] In the embodiment of Figure 8, the retaining frame 35 is a system pre-equipped with all the base connectors 21. The assembly can be plugged onto the bipolar plates 13 in a single operation.

[0062] In the embodiment of figures 9a and 9b, the bipolar plates 13 are without protrusion 17. It is then necessary to divert the air and hydrogen circulation circuits to the edge of the bipolar plate 13 in order to have a contact reception space on the bipolar plate 13 corresponding to the contact reception area 16.

[0063] The base connector 21 is connected to the edges of the bipolar plates 13 via the slotted base contacts 23. A base contact 23 has a slot that directly receives an edge of a corresponding bipolar plate 13 without a protrusion 17. A movable connector 41 is inserted and locked into the base connector 21.

[0064] The locking elements consist of a tab 61 of the mobile connector 41 intended to cooperate with a correspondingly shaped housing 62 of the base connector 21. The stacking of the base connectors 21 is possible by staggering the mounting of the base connectors 21 on the bipolar plates 13, as shown in figure 9a.

[0065] The contacts 43 of the movable connectors 41 can be piston contacts. These piston contacts 43, which move in translation, are spring-loaded to improve electrical continuity between the bipolar plates 13 and the contacts 43 of the base connector 21.

[0066] A rear fitting 63 is integrated into the mobile connector 41 to ensure the retention of an electrical harness 52.

[0067] Of course, the different features, variants and / or embodiments of the present invention can be combined with each other in various ways as long as they are not incompatible or mutually exclusive.

[0068] Furthermore, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms, and other variations that a person skilled in the art may envision within the scope of the present invention, and in particular all combinations of the different modes of operation described above, which may be considered separately or in combination.

Claims

DEMANDS 1. Assembly for a fuel cell comprising: - a fuel cell (11) comprising at least two bipolar plates (13), and - a base connector (21), characterized in that each bipolar plate (13) comprises at least one contact receiving area (18), - the base connector (21) comprising a body (22) made of an electrically insulating material and at least two base contacts (23), each base contact (23) being inserted inside a through opening (26) made in the body (22), each base contact (23) having a slotted end (27) intended to establish local pinch contact with the contact receiving area (18) of a corresponding bipolar plate (13) so as to ensure an electrical connection between the base contact (23) and the corresponding bipolar plate (13), the slotted end (27) of the base contact (23) having a slot inside which is inserted a protrusion (17) of a bipolar plate (13).

2. Assembly according to claim 1, characterized in that a contact receiving zone (18) is constituted by an outgrowth (17) made in an edge of the bipolar plate (13).

3. Assembly according to claim 1 or 2, characterized in that the base connector (21) comprises at least one separation guide (32) for bipolar plates (13) intended to be inserted between two consecutive bipolar plates (13).

4. Assembly according to claim 3, characterized in that the base connector (21) has at least two separation guides (32) arranged on either side of a base contact (23), such that a part of each separation guide (32) covers a portion of the base contact (23) to prevent a short circuit between the bipolar plate (13) to which the base contact (23) is connected and an adjacent bipolar plate (13).

5. Assembly according to any one of claims 1 to 4, characterized in that the base connector (21) comprises a plurality of base contacts (23) arranged along at least one row of contacts (R1, R2), two adjacent base contacts (23) being separated from each other along a longitudinal extension direction (L1) of an edge of a bipolar plate (13) and along a vertical direction (L2) by a distance corresponding to a gap between two consecutive bipolar plates (13).

6. Assembly according to any one of claims 1 to 5, characterized in that the base connector (21) has two lateral lugs (33) intended to cooperate with a retaining frame (35) to retain the base connector (21) on the fuel cell (11).

7. Assembly according to any one of claims 1 to 6, characterized in that it further comprises a movable connector (41) comprising at least two movable contacts (43) intended to establish an electrical connection with the base contacts (23).

8. Assembly according to claim 7, characterized in that the movable contacts (43) each have an end disposed inside a portion selected from a male portion or a female portion which is inserted on the front face inside another complementary portion selected from a male portion or a female portion of the base connector (21) disposed on the rear face of the base connector (21) so as to establish electrical continuity to the bipolar plates (13).

9. Assembly according to claim 7 or 8, characterized in that the mobile connector (41) comprises at least one locking element intended to cooperate with a locking element of complementary shape made in the mobile connector (41) so as to allow the locking of the mobile connector (41) onto the base connector (21).

10. Assembly according to any one of claims 7 to 9, characterized in that the base connector (21) and the movable connector (41) comprise means of error-proofing to avoid reverse mounting between the mobile connector (41) and the base connector (21).

11. Assembly according to any one of claims 1 to 10, characterized in that it comprises at least one electrical insulation cover (56) that can be substituted for the base connector (21).

12. Assembly according to claim 11, characterized in that the electrical insulation cover (56) has separation guides (60) to avoid any contact between the bipolar plates (13).

13. Assembly according to any one of claims 1 to 12, characterized in that the base connector (21) has a rear fitting (63) ensuring the retention of an electrical harness (52).

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