Fuel cell stack and method of manufacturing such a stack

Abstract

Fuel cell stack and method for manufacturing such a cell Fuel cell stack, comprising a plurality of cells arranged successively in a direction (Z), called the stacking direction, each cell comprising: an assembly comprising two electrodes and a membrane forming an electrolyte; and two bipolar plates, each bipolar plate comprising at least one housing (Tc), called the connection housing for receiving an electrical connector; each connection housing (Tc) having an opening having a maximum dimension Dc, a bipolar plate comprises at least one housing (Ti), called the inactive housing, having an opening with a maximum dimension Di strictly less than Dc, and the mouth of a connection housing (Tc) of the first bipolar plate: is located at right angles, in a direction parallel to the stacking direction (Z), to the mouth of an inactive housing (Ti) of the second bipolar plate;and masks at least part of the mouth of the inactive housing (Ti) of the second bipolar plate. Figure for the abstract: Fig.1;

Description

Title of the invention: Fuel cell stack and method of manufacturing such a stack Technical field

[0001] The present invention relates to fuel cells, in particular the manufacture of such a cell. STATE OF THE ART

[0002] Generally speaking, a fuel cell comprises a stack, usually referred to as a "stack", of cells. The cells of the stack comprise a membrane located between two metal plates, called bipolar plates. A bipolar plate is common to two consecutive cells of the stack. At each of its ends, the stack also comprises a cell, called an end cell, located between a monopolar end metal plate and a bipolar plate. The membrane comprises a positive and a negative electrode (anode and cathode) having an electrical potential during operation of the cell. The membrane is also called an AME (i.e. "Membrane Electrode Assembly").

[0003] Measuring the voltages of the cells within a stack is generally carried out by inserting male or female plugs into the bipolar plate which has orifices complementary to the plugs. For example, French patent application FR2887690 can be cited which discloses a bipolar plate comprising a hollow housing intended to receive a collector. For example, certain devices use male plugs which are generally grouped in small groups, i.e. between two and twenty plugs. A high number facilitates the mechanical holding of the plugs in their housings forming female orifices, on the other hand a high number hinders the installation of the plugs and can pose mechanical tolerance problems if the effective spacing between two cells of the stack, also called cell "pitch", differs from the average spacing.Generally speaking, the pitch of a cell is the sum of the thicknesses or heights, measured in the active area of ​​the cell, of a bipolar plate and the membrane. The pitch can be around 1 mm.

[0004] The set of measurement sockets is generally called CVP (Cell-Voltage Pick-up). The CVP is the component that connects the stack to a measuring component that performs voltage measurements using electronic components, the measuring component is called CVM (acronym for “Cell Voltage Monitoring”).

[0005] There are different types of CVPs. For example, we can cite international application WO202286864 which discloses connectors which electrically couple to the bipolar plates using tabs which pinch the edges of the bipolar plate. In this case the connector is a female plug and the CVPs include male plugs. But this system is relatively bulky since electrical insulation must be introduced on the female plugs, thus increasing the minimum measurement pitch between two male plugs of the CVP.

[0006] There are also fuel cells for which housings are formed at the edge of the bipolar plates and form female sockets configured to receive male plugs of the CVP.

[0007] But the installation of the male plugs can be tricky and could be incompatible with industrialization since it involves inserting the plugs into a housing whose largest dimension is smaller than the pitches of the cells of the battery. Furthermore, the deformations and manufacturing tolerances of the components of a complete stack generally generate a variable cell pitch, for example + / - 100 pm and the centering and manufacturing tolerances do not allow for perfect alignment depending on the direction of stacking of the cells, and a lateral offset of + / - 100-200 pm can be obtained between the housings formed by the female orifices.

[0008] In addition to the above manufacturing tolerances, there is misalignment generated by the stacking of cells and the lack of rigidity of the structural components of a stack.

[0009] The same is true for the manufacture of CVPs, which also have wide tolerances in the design due to the flexibility required by the plugs and their length.

[0010] As a result, when a CVP with several plugs is presented to a group of cells, the plugs are frequently inserted into "the wrong housing", in three cases. In the first case, the plug is inserted between a bipolar plate and an AME instead of being inserted into the housing of the bipolar plate provided for this purpose. The electrical contact is then poor and there is a risk of short circuit if the plug damages the FAME providing the electrical insulation. In a second case, two successive plugs are inserted into two different housings of the same bipolar plate. The voltage measured between the two plugs in question will then be zero. In a third case, a bipolar plate is not taken by any plug. The cell in question is not monitored and the measurement of the following cell will indicate the sum of the voltage of the unmeasured cell with that of the following cell.

[0011] In practice, these three cases are often encountered in combination for the same cell. In the last two cases, the operation of the fuel cell is not possible without the addition of control artifacts (such as ignoring the cells

[0012]

[0013]

[0014]

[0015]

[0016] concerned). In this case, there is a risk of malfunction of the fuel cell. There is therefore a need to facilitate the insertion of an electrical connector for taking measurements, in particular of the voltages, of the cells of a fuel cell. ABSTRACT An object of the invention is to overcome these drawbacks, and more particularly to provide means to facilitate the insertion of several connectors of a set of CVP measurement sockets. Other objects, features and advantages of the present invention will become apparent from a consideration of the following description and accompanying drawings. According to one aspect of the invention, a fuel cell stack is provided, the stack comprising a plurality of cells arranged successively in a direction, called the stacking direction, each cell comprising: - an assembly comprising two electrodes and a membrane forming an electrolyte, the membrane being placed between the two electrodes; and - two bipolar plates enclosing the assembly, each bipolar plate of a cell also acting as a bipolar plate for another cell adjacent to the cell; - for at least one cell, each bipolar plate comprising at least one housing, called connection housing, configured to receive an electrical connector intended to measure an electrical parameter of the battery; - each connection housing extending mainly in one direction, called the connection direction, contained in a plane perpendicular to the stacking direction; - each connection housing having a mouth forming an opening having a maximum dimension of taking in projection in a plane, called transverse, perpendicular to the connection direction. For said at least one cell, each bipolar plate comprises at least one housing, called inactive, having a mouth forming an opening having a maximum dimension Di, taken in projection in the transverse plane, such that De is strictly greater than Di, and in that the stack is configured so that for a first bipolar plate of said at least one cell, the mouth of a connection housing of the first bipolar plate: - is located to the right, in a direction parallel to the stacking direction, of the mouth of an inactive housing of the second bipolar plate of said at least one cell; and - masks at least part of the mouth of the inactive housing of the second bipolar plate according to a projection in the transverse plane.

[0017] Thus, the masking of the inactive housings by the connection housings reduces, or even eliminates, the risk of a male plug being inserted into a connection housing. Thus, it is easier to insert the connectors for measuring an electrical parameter characteristic of the cell, for example a voltage of at least one cell of the cell. The assembly of a fuel cell and the plugs for measuring an electrical parameter is therefore made considerably more reliable and faster. The invention thus makes it possible to make fuel cells more reliable and less expensive.

[0018] According to another aspect, a fuel cell is provided, comprising a stack as defined above, a first distribution circuit configured to distribute a first fluid to the first electrodes of the cells of the cell and a second distribution circuit configured to distribute a second fluid to the second electrodes of the cells of the cell.

[0019] According to another aspect, there is provided a method of manufacturing a fuel cell stack, comprising providing: - a stack comprising a plurality of cells arranged successively in a direction, called stacking, each cell comprising: - an assembly comprising two electrodes and a membrane forming an electrolyte, the membrane being placed between the two electrodes; and - two bipolar plates enclosing the assembly, each bipolar plate of a cell also acting as a bipolar plate for another cell adjacent to the cell; - the method comprising a first formation, for each bipolar plate of at least one cell, of at least one housing, called connection housing, configured to receive an electrical connector intended to measure an electrical parameter of the battery; - each connection housing extending mainly in one direction, called the connection direction, contained in a plane perpendicular to the stacking direction; - each connection housing having a mouth forming an opening having a maximum dimension of taking in projection in a plane, called transverse, perpendicular to the connection direction.

[0020] The method comprises, for each bipolar plate of said at least one cell, a second formation of at least one housing, called inactive, having a mouth forming an opening having a maximum dimension Di, taken in projection in the transverse plane, such that De is strictly greater than Di, and in that the stack is configured so that for a first bipolar plate of said at least one cell, the mouth of an inactive housing of the first bipolar plate: - is located to the right, in a direction parallel to the stacking direction, of the mouth of an inactive housing of the second bipolar plate of said at least one cell; and - masks at least part of the mouth of the inactive housing of the second bipolar plate according to a projection in the transverse plane. BRIEF DESCRIPTION OF THE FIGURES

[0021] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

[0022] [Fig.l] [Fig.l] schematically illustrates a sectional view of an embodiment of a stack of cells of a fuel cell;

[0023] [Fig.2][Fig.3][Fig.4][Fig.5][Fig.6] Figures 2 to 6 schematically illustrate perspective views of the main stages of a method of implementing a fuel cell manufacturing process;

[0024] [Fig.7] [Fig.7] schematically illustrates a perspective view of another mode implementation of the manufacturing process of a fuel cell; and

[0025] [Fig.8] [Fig.8] schematically illustrates a perspective view of another mode implementation of the manufacturing process of a fuel cell.

[0026] The drawings are given as examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily on the scale of practical applications. DETAILED DESCRIPTION

[0027] Before commencing a detailed review of embodiments and implementations of the invention, optional features are set out below which may optionally be used in combination or alternatively.

[0028] According to one example, for each cell, the mouth of a connection housing of a bipolar plate of a first cell masks at least 10%, and preferably between 10% and 50%, according to a projection in said transverse plane, the mouth of the inactive housing of the cell which is successive to it. Preferably, the mouth of a connection housing of a bipolar plate of a first cell completely masks, according to a projection in said transverse plane, the mouth of the inactive housing of the cell which is successive to it.

[0029] Thus, the connector brought along the connection direction cannot enter the inactive housing. This makes it possible to further reduce, or even eliminate, the risks of inserting a connector into an inappropriate housing.

[0030] According to one example, the mouth of each connection housing has a opening having a dimension De strictly greater than the pitch of at least one cell of the stack, the pitch of a cell being equal to the thickness Epb of a bipolar plate added to the thickness Ea of the assembly, the thicknesses Epb and Ea being measured according to the stacking direction.

[0031] According to one example, the mouth of each connection housing has an opening having a dimension De less than or equal to twice the pitch of a cell.

[0032] According to one example, each connection housing and each inactive housing comprises a longitudinal portion, the longitudinal portions of the inactive housings being identical, in terms of shape and dimension, to at least a part of each longitudinal portion of the connection housings.

[0033] According to one example, each connection housing comprises a longitudinal portion and a portion, called a guide portion, which extends the longitudinal portion in the direction of the mouth and which flares in the direction of the mouth.

[0034] According to one example, the guide portion continuously flares out to the mouth.

[0035] According to one example, the guide portion forms a truncated cone.

[0036] According to one example, the guide portion flares to an end portion distal, whose section is constant and which includes the mouth.

[0037] According to one example, the guide portion comprises a truncated cone and a cylindrical part forming the distal end portion, located between the truncated cone and the mouthpiece.

[0038] According to one example, the openings of the mouths of the connection housings are contained in a first plane parallel to the stacking direction and perpendicular to the connection direction, the openings of the mouths of the inactive housings are contained in a second plane parallel to the first plane, and the first plane is located at a distance from the second plane such that the mouths of the connection housings project from the second plane.

[0039] According to an example, a first bipolar plate of a cell comprises several connection housings having openings aligned in a first transverse direction perpendicular to the stacking direction and perpendicular to the connection direction, and the second bipolar plate of the cell comprises several connection housings having openings aligned in a second transverse direction parallel to the first transverse direction, each connection housing of the second bipolar plate being located, in the stacking direction, at right angles to a space separating two connection housings of the first bipolar plate.

[0040] According to one example, a first bipolar plate of a cell comprises a first pair of connection housings having openings aligned in a first transverse direction perpendicular to the stacking direction and perpen dicular to the connection direction, and the second bipolar plate of the cell comprises a second pair of connection housings having openings aligned in a second transverse direction parallel to the first transverse direction, the connection housings of the second pair being located, in the stacking direction, at right angles to an area separating the two connection housings of the first pair.

[0041] According to an example, a first bipolar plate of a cell comprises a first pair of connection housings having openings aligned in a first transverse direction perpendicular to the stacking direction and perpendicular to the connection direction, and the second bipolar plate of the cell comprises a second pair of connection housings having openings aligned in a second transverse direction parallel to the first transverse direction, the connection housings of the second pair being located, in the stacking direction, in line with an area of ​​the first bipolar plate devoid of connection housings.

[0042] According to one example, each bipolar plate comprises two monopolar plates, called bipolar half-plates, respectively comprising two faces facing each other, and each connection and inactive housing are delimited by the two faces.

[0043] According to one example, the method comprises forming, for each bipolar plate of at least one cell, at least two connection housings, each connection housing comprising a longitudinal portion and a guide portion widening from the longitudinal portion towards the mouth, producing the inactive housings comprising cutting, for each bipolar plate, and for only some of the connection housings, a portion of the connection housing so as to remove at least part of the guide portion, and during the cutting, the guide portion of the other connection housings being retained.

[0044] According to one example, the formation, for each bipolar plate of at least one cell, of said at least two connection housings is carried out using the same stamping tool.

[0045] In Figures 1 and 6, a stack 1 for a fuel cell 60 is shown. The stack 1 comprises a plurality of cells 3, 4 arranged successively in a direction Z, called the stacking direction. The stack 60 further comprises two cells 2, 5, called end cells, stacked with the other cells 3, 4 of the stack 1. Each cell 2 to 5 of the stack 60 comprises an assembly comprising two electrodes 6, 7 and a membrane 8 forming an electrolyte, the membrane being placed between the two electrodes 6, 7. Each cell 3, 4 of the stack 1 further comprises two bipolar plates B1 to B3 enclosing the assembly, each bipolar plate B1 to B3 of a cell 3, 4 also acting as a bipolar plate B1 to B3 for another cell adjacent to the cell. A first adjacent cell of a second cell is understood to mean a cell that succeeds or precedes the second cell in the stacking direction Z. In addition, each bipolar plate B1 to B3 comprises two monopolar plates M1, M2 in contact with each other. In other words, the two monopolar plates respectively comprise two faces facing each other. Preferably, each end cell is sandwiched between an end monopolar plate ME1, ME2 and a monopolar plate M2, M1 of a bipolar plate B1, B3. In particular, the monopolar plates M1, M2 of a bipolar plate B1 to B3 are structurally different from the end monopolar plates ME1, ME2. The monopolar plates Ml, M2 of a bipolar plate Bl to B3 are also called bipolar half-plates.A cell 2 to 5 of the stack 60 may further comprise two gas diffusion layers 9, each gas diffusion layer 9 being located between an electrode 6, 7 and a monopolar plate M1, M2 (or bipolar half-plate).

[0046] The cell 60 comprises a main source 61 of a first fluid and a secondary source 62 of a second fluid. The cell 60 comprises a first distribution circuit 63 fluidly connected to the main source and configured to distribute the first fluid to the first electrodes of the cells. For example, the first fluid is dihydrogen and the first electrodes correspond to the anodes where the ionization of the dihydrogen takes place. The cell 60 comprises a second distribution circuit 64 fluidly connected to the secondary source and configured to distribute the second fluid to the second electrodes of the cells. For example, the second fluid is dioxygen and the second electrodes correspond to the cathodes where the formation of water takes place from, in particular, dioxygen.

[0047] The battery 60 may also comprise electrical connectors configured to be inserted into the connection housings Te respectively in order to be able to measure an electrical parameter of the battery 60.

[0048] Furthermore, for at least one cell 3, 4 of the stack 1, each bipolar plate B1 to B3 comprises at least one housing Te, called a connection housing, configured to receive an electrical connector intended to measure an electrical parameter of the battery, in particular a voltage of a cell. In particular, each connection housing Te corresponds to a female socket intended to cooperate with a male socket of a connector. For example, a connector comprises a plug and forms a male socket.

[0049] Each connection housing Te extends in a direction Le, called the connection direction, contained in a plane X, Y perpendicular to the stacking direction Z. Preferably, this connection direction Le is parallel to a translation direction that the male plug must perform relative to the connection housing Te to allow penetration and cooperation of the male plug in the connection housing Te.

[0050] Furthermore, each connection housing Te has a mouth forming an opening having a maximum dimension De taken in projection in a plane X, Z, called transverse, perpendicular to the connection direction Le.

[0051] More particularly, for at least one cell 3, 4 of the stack 1, each bipolar plate B1 to B3 comprises at least one housing Ti, called inactive, having a mouth forming an opening having a maximum dimension Di, taken in projection in the transverse plane X, Z. Each inactive housing Ti extends along the connection direction Le.

[0052] In particular, De is strictly greater than Di. Furthermore, the stack 1 is configured so that for a first bipolar plate B1 of a cell 3, the mouth of an active housing of the first bipolar plate B1: - is located to the right, in a direction parallel to the stacking direction Z, of the mouth of an inactive housing Ti of the second bipolar plate B2 of cell 3; and - masks at least part of the mouth of the inactive housing Ti of the second bipolar plate according to a projection in the transverse plane X, Z.

[0053] In particular, such a connection housing Te forms a guide to facilitate the insertion of a male plug of an electrical connector. In other words, if a plug of a CVP comes into contact with an inactive housing Ti, the plug will be directed towards the connection housing Te which at least partially masks it. Thus, by facilitating the insertion of a CVP plug into a connection housing Te, the risk of inserting the plug between a bipolar plate B1 to B3 and a membrane 8 is reduced. The inactive housings do not allow a measurement to be taken since their openings are at least partially masked by the openings of the connection housings Te. [Fig.l] illustrates, by a hatched area Zm, the masking of an inactive housing Ti of the cell B2 by a connection housing Te of the cell Bl.In this example, the inactive housing Ti of the cell B2 is partly masked by the connection housing Te of the cell BL. Generally, the mouth ETc of a connection housing Te of a first bipolar plate Bl of a cell 3 masks, according to a projection in the transverse plane X, Z, at least 10%, preferably between 10% and 50%, the mouth ETi of an inactive housing Ti of the second bipolar plate of the cell 3. Furthermore, this mouth ETi of the inactive housing Ti of the second bipolar plate of the cell 3 can be masked, according to a projection in the transverse plane X, Z, by at least 10%, preferably between 10% and 50%, by the mouth ETc of a connection housing Te of a first bipolar plate B3 of another cell 4 successive to the cell 3 according to the stacking direction Z.

[0054] Furthermore, each connection housing is located to the right of an inactive housing. It is thus easy to stack the cells 2 to 5, avoiding the mouths of the connection housings Te colliding with each other. In other words, several connection housings are created with different alignments.

[0055] For example, each connection housing Te and inactive Ti is formed so as to extend longitudinally along the connection direction Le between two monopolar plates M1, M2 (or bipolar half-plates) of a bipolar plate B1 to B3.

[0056] The mouths of the connection housings may have a circular, oval, polygonal or square shape.

[0057] According to another example, for each cell, the mouth of a connection housing Te of a bipolar plate of a first cell can mask, according to a projection in said transverse plane X, Z, at least 40%, or at least 60%, or at least 80%, or even entirely, the mouth of the inactive housing Ti of the cell which follows it.

[0058] The mouth of each connection housing has an opening having a dimension De strictly greater than the pitch of at least one cell of the stack, the pitch of a cell being equal to the thickness Epb of a bipolar plate added to the thickness Ea of the assembly, the thicknesses Epb and Ea being measured along the stacking direction Z. Thus, an insertion width greater than the pitches of the cells of the fuel cell 60 is provided. For example, the pitch of a cell may correspond to the average of the pitches of the cells of the stack 60, or to the maximum pitch of the cells of the stack 60.

[0059] The mouth of each connection housing has an opening having a dimension De less than or equal to twice the pitch of a cell.

[0060] Preferably, the dimension De of the openings of the mouths of the connection housings Te has a value between one and two times the pitch of a cell. These values ​​depend on the geometry of the widening and the deformability of the material used to make the bipolar plates. The strong constraints on the forming of the bipolar plate are then limited since the greater the dimension De of the opening of the mouth, the greater the stretching of the metal will be. A lower constraint is also applied to the overhang of T AME, to ensure electrical insulation between the mouths of the connection housings. The AME may comprise a flexible polymer (for example polynaphthalate PEN or polytetraphthalate PET) that is not very thick (less than 100 pm) and which must conform to the external shape of the mouths. Indeed, the electrical insulation between the bipolar plates of a cell is generally carried out by the AME of the cell.That is, the AME located between the bipolar plates protrudes by a few millimeters from the periphery of the bipolar plates, for example with a maximum thickness of 100 pm. The AME is . configured to deform to fit the shape of the mouths of the Te connection housings.

[0061] Alternatively, De may be strictly greater than twice the pitch of a cell.

[0062] For example, each connection housing and each inactive housing comprises a longitudinal portion, the longitudinal portions of the inactive housings being identical, in terms of shape and dimension, to at least part of each longitudinal portion of the connection housings. Preferably, the longitudinal portion has a constant section along the connection direction Le in projection in a plane perpendicular to the stacking direction. Each connection housing may comprise a longitudinal portion and a portion, called a guide portion, which extends the longitudinal portion in the direction of the mouth and which widens in the direction of the mouth. Preferably, the guide portion widens continuously up to the mouth, preferably in a constant manner. The guide portion may form a truncated cone. For example, the guide portion Pg may form a Gabriel trumpet.

[0063] According to another example, the guide portion flares to a distal end portion, the section of which is constant and which comprises the mouth. The guide portion may further comprise a truncated cone and a cylindrical part forming the distal end portion, located between the truncated cone and the mouth.

[0064] The longitudinal portion may have a length greater than or equal to ten times its width. The width being measured along a plane parallel to the stacking direction Z and perpendicular to the connection direction Le. Thus, connection housings are provided suitable for electrical connectors provided with springs and which do not penetrate the bipolar plate, and for pivoting knives which would penetrate the plate.

[0065] For example, the opening of at least one connection housing Te extends in a plane parallel to the stacking direction and protrudes at least in part and in the stacking direction, an external face of a bipolar plate of a second successive cell.

[0066] According to another example, each connection housing of a bipolar plate has a position offset in a direction parallel to the stacking direction relative to the position of each connection housing of a bipolar plate of a successive cell. In other words, each connection housing of a bipolar plate is not located at right angles, in a direction parallel to the stacking direction, to a connection housing of a bipolar plate of an adjacent cell.

[0067] In [Fig. 6], an embodiment is shown, in which the mouths of the connection housings are arranged in a staggered pattern, along a plane parallel to the alignment direction. A first bipolar plate of a cell comprises several connection housings aligned in a first transverse direction perpendicular to the stacking direction, and the second bipolar plate of the cell comprises several connection housings aligned in a second transverse direction perpendicular to the stacking direction. According to this staggered pattern, each connection housing of the second bipolar plate is located, in the stacking direction, in line with a space separating two connection housings of the first bipolar plate. In particular, the space is devoid of connection housings.

[0068] Another pattern, called a mirror pattern, may be chosen for arranging the mouths of the connection housings. According to the mirror pattern, a first bipolar plate of a cell comprises a first pair of connection housings aligned in a first transverse direction perpendicular to the stacking direction, and the second bipolar plate of the cell comprises a second pair of connection housings aligned in a second transverse direction perpendicular to the stacking direction. According to this mirror pattern, the connection housings of the second pair are located, in the stacking direction, at right angles to a zone separating the two connection housings of the first pair. In particular, the zone is devoid of connection housings.

[0069] Another pattern, called a group of two pattern, may be chosen for arranging the openings of the connection housings. According to the group of two pattern, a first bipolar plate of a cell comprises a first pair of connection housings aligned in a first transverse direction perpendicular to the stacking direction, and the second bipolar plate of the cell comprises a second pair of connection housings aligned in a second transverse direction perpendicular to the stacking direction. According to this group of two pattern, the connection housings Te of the second pair are located, in the stacking direction, at right angles to a zone of the first bipolar plate devoid of connection housings Te.

[0070] Each connection and inactive housing are delimited by the two faces facing each other of two monopolar plates M1, M (or bipolar half-plates) of a bipolar plate B1 to B3.

[0071] It is also possible to carry out the measurements not for all the cells in the stack, but for all N cells. In this case, the maximum distance De of the mouthpiece openings is N*P, with N an integer corresponding to the number of cells and P corresponding to the cell pitch (in millimeters).

[0072] In Figures 2 to 6, the main steps of a method for manufacturing a stack 1 for a fuel cell 60 are shown. In particular, as illustrated in [Fig.2], the method comprises a formation, for each bipolar plate of at at least one cell, of at least two connection housings Te. Then, in [Fig. 3] cutting lines have been shown for producing the inactive housings Ti. For example, the method comprises producing the inactive housings comprising, for each bipolar plate, and for only some of the connection housings, a portion of the connection housing so as to remove at least part of the guide portion. In particular, part of the guide portion Pg is removed so as to obtain Di strictly less than De. For example, part of the guide portion Pg can be removed so as to obtain Di less than or equal to the pitch of at least one cell of the fuel cell 60. In [Fig. 3], a first cutting line has been shown in solid lines to obtain a first bipolar plate, of a first type, and a second cutting line in dotted lines to obtain the second bipolar plate, of a second type.A first bipolar plate Bl, of the first type, illustrated in [Fig.4] and a second bipolar plate B2, of the second type, illustrated in [Fig.5] are thus obtained. When cutting, the flared portion of the other connection housings is retained. For example, the cutting of certain connection housings is carried out so that the mouths of the connection housings are placed in a staggered manner, as illustrated in [Fig.6], along a plane parallel to the stacking direction and perpendicular to the connection directions Le. In other words, a bipolar plate Bl to B3 comprises a plurality of spaces forming a recess on the contour of the plate Bl to B3, the mouths of the inactive housings Ti are located in the spaces, so that: a. the mouths of the connection housings Te are located on a first line contained in the plane X, Y; . b. the mouths of the inactive housings Ti are located on a second line contained in the X, Y plane, the second line being parallel to the first line and located at a non-zero distance Es, as illustrated in figures 4 and 6.

[0073] In [Fig.7], other cutting lines have been shown to obtain a pattern in mirror. In [Fig.8], other cutting lines have been shown to obtain a pattern in groups of two.

[0074] An advantage of producing the bipolar plates with all the housings flared and then cutting out those which will not be used, by forming the inactive housings Ti, is to be able to produce the two bipolar plates of the same cell with a single set of stamping of the plates. The difference between the first bipolar plate and the second bipolar plate is achieved by a difference in cutting. This avoids multiplying the tools for manufacturing the bipolar plates which are very expensive.

[0075] Advantageously, with bipolar plates of two different types, all the bipolar plates of the stack 60 can be produced. The variety of bipolar plates to be used is saved.

Claims

1. Claims Stack (1) for fuel cell, the stack (1) comprising a plurality of cells (3, 4) arranged successively in a direction (Z), called stacking direction (1), each cell comprising: - an assembly comprising two electrodes (6, 7) and a membrane (8) forming an electrolyte, the membrane being placed between the two electrodes; and - two bipolar plates (B 1-B3) enclosing the assembly, each bipolar plate of a cell also acting as a bipolar plate for another cell adjacent to the cell; - for at least one cell (3, 4), each bipolar plate (B1-B3) comprising at least one housing (Te), called connection housing, configured to receive an electrical connector intended to measure an electrical parameter of the battery; - each connection housing (Te) extending mainly in a direction (Le), called connection, contained in a plane (X, Y) perpendicular to the stacking direction (Z); - each connection housing (Te) having a mouth (ETc) forming an opening having a maximum dimension taken in projection in a plane (X, Z), called transverse, perpendicular to the connection direction (Le); characterized in that for said at least one cell (3, 4), each bipolar plate (B1-B3) comprises at least one housing (Ti), called inactive, having a mouth (ETi) forming an opening having a maximum dimension Di, taken in projection in the transverse plane (X, Z), such that De is strictly greater than Di, and in that the stack (1) is configured so that for a first bipolar plate of said at least one cell, the mouth of a connection housing (Te) of the first bipolar plate: - is located to the right, in a direction parallel to the stacking direction (Z), of the mouth of an inactive housing (Ti) of the second bipolar plate of said at least one cell; and - masks at least part of the mouth of the inactive housing (Ti) of the second bipolar plate according to a projection in the transverse plane (X, Z).

2. Stack (1) according to claim 1, in which, for each cell, the mouth of a connection housing (Te) of a bipolar plate of a first cell masks, according to a projection in said transverse plane (X, Z), at least 10%, preferably between 10% and 50%, of the mouth of the inactive housing (Ti) of the cell which follows it.

3. Stack (1) according to any one of the preceding claims, in which the mouth of each connection housing (Te) has an opening having a dimension De strictly greater than the pitch of at least one cell of the stack, the pitch of a cell being equal to the thickness Epb of a bipolar plate added to the thickness Ea of the assembly, the thicknesses Epb and Ea being measured in the stacking direction (Z).

4. Stack (1) according to the preceding claim, in which the mouth of each connection housing (Te) has an opening having a dimension De less than or equal to twice the pitch of a cell.

5. Stack (1) according to any one of the preceding claims, in which each connection housing (Te) and each inactive housing (Ti) comprises a longitudinal portion, the longitudinal portions of the inactive housings (Ti) being identical, in terms of shape and dimension, to at least part of each longitudinal portion of the connection housings (Te).

6. Stack (1) according to any one of the preceding claims, in which each connection housing (Te) comprises a longitudinal portion (PI) and a portion, called a guide portion (Pg), which extends the longitudinal portion (PI) in the direction of the mouth and which widens in the direction of the mouth.

7. Stack (1) according to any one of the preceding claims, in which the guide portion (Pg) continuously flares up to the mouth.

8. Stack (1) according to the preceding claim, in which the guide portion (Pg) forms a truncated cone.

9. Stack (1) according to any one of claims 1 to 5, in which the guide portion flares out to a distal end portion, the section of which is constant and which comprises the mouth.

10. Stack (1) according to the preceding claim, in which the guide portion comprises a truncated cone and a cylindrical part forming the distal end portion, located between the truncated cone and the mouth.

11. Stack (1) according to any one of the preceding claims, in which the openings of the mouths (ETc) of the connection housings (Te) are contained in a first plane parallel to the stacking direction (Z) and perpendicular to the connection direction (Le), the openings of the mouths (ETi) of the inactive housings (Ti) are contained in a second plane parallel to the first plane, and the first plane is located at a distance from the second plane so that the mouths (ETc) of the connection housings (Te) project from the second plane.

12. Stack (1) according to any one of the preceding claims, in which a first bipolar plate (Bl) of a cell comprises several connection housings (Te) having openings aligned in a first transverse direction perpendicular to the stacking direction (Z) and perpendicular to the connection direction (Le), and the second bipolar plate (B2) of the cell comprises several connection housings (Te) having openings aligned in a second transverse direction parallel to the first transverse direction, each connection housing (Te) of the second bipolar plate (B2) being located, in the stacking direction (Z), at right angles to a space separating two connection housings (Te) of the first bipolar plate (Bl).

13. Stack (1) according to any one of claims 1 to 12, wherein a first bipolar plate (B1) of a cell comprises a first pair of connection housings (Te) having openings aligned in a first transverse direction perpendicular to the stacking direction (Z) and perpendicular to the connection direction (Le), and the second bipolar plate (B2) of the cell comprises a second pair of connection housings (Te) having openings aligned in a second transverse direction parallel to the first transverse direction, the connection housings (Te) of the second pair being located, in the stacking direction (Z), at the right of an area separating the two connection housings (Te) of the first pair.

14. Stack (1) according to any one of claims 1 to 13, in which a first bipolar plate (Bl) of a cell comprises a first pair of connection housings (Te) having openings aligned in a first transverse direction perpendicular to the stacking direction (Z) and perpendicular to the connection direction (Le), and the second bipolar plate (B2) of the cell comprises a second pair of connection housings (Te) having openings aligned in a second transverse direction parallel to the first transverse direction, the connection housings (Te) of the second pair being located, in the stacking direction (Z), at right angles to an area of ​​the first bipolar plate (Bl) devoid of connection housings (Te).

15. Stack (1) according to any one of the preceding claims, in which each bipolar plate (B 1 to B3) comprises two monopolar plates (Ml, M2), called bipolar half-plates, respectively comprising two faces (Fl, F2) facing each other, and each connection housing (Te) and inactive housing (Ti) are delimited by the two faces (Fl, F2).

16. Fuel cell, comprising a stack (1) according to any one of the preceding claims, a first distribution circuit (63) configured to distribute a first fluid to the first electrodes (6) of the cells (2 to 5) of the stack (60) and a second distribution circuit (64) configured to distribute a second fluid to the second electrodes (7) of the cells (2 to 5) of the stack (60).

17. A method of manufacturing a stack (1) for a fuel cell, the method comprising providing a stack (1) comprising a plurality of cells (3, 4) arranged successively in a direction (Z), called the stack (1) direction, each cell comprising: - an assembly comprising two electrodes (6, 7) and a membrane (8) forming an electrolyte, the membrane being placed between the two electrodes; and - two bipolar plates (B 1-B3) enclosing the assembly, each bipolar plate of a cell also acting as a bipolar plate for another cell adjacent to the cell; the method comprising a first formation, for each bipolar plate of at least one cell, of at least one housing (Te), called connection housing, configured to receive an electrical connector intended to measure an electrical parameter of the battery; - each connection housing (Te) extending mainly in a direction (Le), called connection, contained in a plane (X, Y) perpendicular to the stacking direction (Z); - each connection housing (Te) having a mouth (ETc) forming an opening having a maximum dimension taken in projection in a plane (X, Z), called transverse, perpendicular to the connection direction (Le); characterized in that the method comprises, for each bipolar plate of said at least one cell, a second formation of at least one housing (Ti), called inactive, having a mouth forming an opening having a maximum dimension Di, taken in projection in the transverse plane (X, Z), such that De is strictly greater than Di, and in that the stack (1) is configured so that for a first bipolar plate of said at least one cell, the mouth (ETi) of an inactive housing (Ti) of the first bipolar plate: - is located to the right, in a direction parallel to the stacking direction (Z), of the mouth of an inactive housing (Ti) of the second bipolar plate of said at least one cell; and - masks at least part of the mouth of the inactive housing (Ti) of the second bipolar plate according to a projection in the transverse plane (X, Z).

18. Method according to the preceding claim, comprising a formation, for each bipolar plate of at least one cell, of at least two connection housings (Te), each connection housing (Te) comprising a longitudinal portion (PI) and a guide portion (Pg) widening from the longitudinal portion in the direction of the mouth (ETc), a development of the inactive housings (Ti) comprising, a cutout, for each bipolar plate, and for only some of the connection housings (Te), of a portion of the connection housing (Te) so as to remove at least part of the guide portion, and during the cutting, the guide portion of the other connection housings (Te) being preserved.

19. Method according to the preceding claim, in which the formation, for each bipolar plate of at least one cell, of said at least two connection housings (Te) is carried out using the same stamping tool.

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