Cartridge, compensation system and fuel cell

Abstract

Cartridge, compensation system and fuel cell Cartridge (1), comprising: a foot (20) sliding relative to a base (10) along a compression direction (X1); a spring (30), applying a pressing force (F30) on the foot (20) along the compression direction (X1); an assembly means (17), for assembling the foot (20) to an end plate (53), for bearing against a stack (51) of electrochemical cells (52) along the compression direction (X1) and while the base (10) is held in the opposite direction; and a retaining system (40), with a primary retaining portion (41) integral with the base (10), and a secondary retaining portion (42) integral with the foot (20), the primary (41) and secondary (42) portions being configured to be coupled, to prevent sliding of the foot (20), and decoupled, to allow sliding of the foot (20). Figure for the abbreviation: Figure 3

Description

Title of the invention: Cartridge, compensation system and fuel cell

[0001] The present invention relates to a cartridge and a dimensional compensation system, for maintaining in compression a stack of electrochemical cells belonging to a fuel cell, relates to a fuel cell comprising such a compensation system and relates to a use of such a cartridge.

[0002] In the field of fuel cells, it is known to compress a stack of electrochemical cells between two terminal plates, located on either side of the stack along the stacking direction, and to protect this assembly in a casing. During its various operating phases, the stack tends to expand and / or contract along the stacking direction for several reasons, notably due to thermal effects and stack aging. To allow this expansion and / or contraction to occur without degradation of the electrochemical cells, it is known to fix a first terminal plate relative to the casing and to make a second terminal plate movable relative to the casing, parallel to the stacking direction.

[0003] To maintain the stack in compression despite the mobility of the second end plate, a compressive force is applied to this second end plate using a dimensional compensation system, including one or more springs. It is known to provide that the springs exert a pull on the second end plate towards the first using tie rods to compress the stack. As an alternative solution, it is known to interpose springs in compression between the second end plate and a fixed plate belonging to the housing, so that the springs push the second end plate towards the first, thus compressing the stack.In both cases, the mobility of the second end plate allows compensation for any expansion or contraction of the stack along the stacking direction, while the stack is kept compressed between the two end plates under the action of the springs.

[0004] These known solutions have several drawbacks. In general, the springs are difficult to install or the assembly of the fuel cell is made difficult due to the presence of the springs, since said springs are designed to apply a force of up to several tons on the stack. Furthermore, although Because the stack must be compressed under a force within a relatively narrow tolerance range, obtaining a precise value for the stack compression using springs is difficult, especially since spring adjustment options are limited, difficult to implement, or nonexistent. Finally, such springs require specific space for integration, thus increasing the overall size of the fuel cell.

[0005] It is these drawbacks that the invention intends to remedy in particular, by proposing new solutions to simplify the compression of a stack of electrochemical cells while improving the precision of this compression and limiting the increase in size.

[0006] To this end, the invention relates to a cartridge for maintaining, in compression along a compression direction, a stack of electrochemical cells belonging to a fuel cell, the cartridge comprising: • a base, through which the cartridge is configured to be retained in the opposite direction to the compression direction, by a retaining wall integral with, or belonging to, the fuel cell; • a foot, which is positioned in the direction of compression relative to the base, sliding relative to the base parallel to the direction of compression; • a spring, which rests on the base to apply a pressing force on the foot along the direction of compression; • an assembly means for assembling the foot to an end plate of the fuel cell, the foot being configured to bear against the end plate in the compression direction to maintain the stack in compression, when the foot is assembled with the end plate by the assembly means and the base is retained in the opposite direction to the compression direction by the retaining wall; and • a retention system, which includes a primary retention portion, integral with the base, and a secondary retention portion, integral with the foot, the primary retention portion and the secondary retention portion being configured to: • be coupled to each other when the cartridge is in a pre-stressed configuration, the primary retaining portion and the secondary retaining portion thus coupled preventing the foot from sliding relative to the base along the compression direction; and • be decoupled from each other when the cartridge is in a released configuration, the primary retention portion and the portion of secondary retention thus decoupled allowing the foot to slide relative to the base along the direction of compression.

[0007] Thanks to the cartridge of the invention, compressing the stack is easily achievable, in that the cartridge can be easily installed in the fuel cell while in its pre-stressed configuration, where the spring action on the foot is contained by the retaining system. In particular, in the pre-stressed configuration, the cartridge can easily be assembled with the end plate via the assembly means, which will provide support against the stack under the action of the spring once the cartridge is in its released configuration.In other words, the ability to individually pre-tension the cartridge, particularly while it is outside the fuel cell, ensures that the spring is installed in the fuel cell by mounting the cartridge while it is already pre-tensioned. This prevents accidental release, provided the cartridge is not otherwise interposed between the end plate and the retaining wall. Once the cartridge is in place and held by the retaining wall, it can easily be moved to the released configuration by separating the primary and secondary retaining portions. This allows the pressing force generated by the spring to be transmitted to the stack via the foot assembled with the end plate.The assembly operation is then simplified and made safer, since the spring is enclosed in a cartridge, which protects the operator from any risk of injury due to significant spring compression.

[0008] Furthermore, the ability to pre-stress the cartridge allows the value of the pressing force to be determined in advance, which will then be applied to the stack. This is because the pressing force can be adjusted when the cartridge is pre-stressed, that is, before the cartridge is installed in the fuel cell. The fact that the cartridge can be assembled with the end plate by means of the assembly advantageously allows for the formation of a single, rigid sub-assembly, comprising the end plate and the cartridge, which can be easily handled. This is particularly advantageous in the preferred case where several cartridges need to be installed, since all the cartridges in the pre-stressed configuration can be assembled with the end plate to form the easily handled single sub-assembly.

[0009] According to advantageous, but not mandatory, aspects of the invention, one or more of the following features may be incorporated, taken individually or in any technically feasible combinations:

[0010] - The assembly means comprises an external coaxial thread with a central axis of the cartridge, the central axis being parallel to the direction, the external thread being arranged around the foot and the secondary retaining portion and being configured to be engaged with an internal thread belonging to the end plate, to assemble the foot with the end plate.

[0011] - The foot comprises a tubular crown, coaxial with the central axis; the base is received inside the tubular crown, thus guiding the sliding of the foot relative to the base parallel to the direction of compression; and the external thread is formed on the tubular crown.

[0012] - The cartridge further includes an anti-rotation element, which is configured to be mounted to prevent rotation of the foot relative to the end plate around the central axis when the external thread is engaged in the internal thread of the end plate and the retaining system is in the released configuration.

[0013] - The retaining system includes a retaining element, via of which the primary retention portion and the secondary retention portion are coupled, when the cartridge is in prestressed configuration.

[0014] - The retaining member comprises a first threaded body.

[0015] - The secondary retention portion is formed by a tapped hole, arranged in a barrel traversing parallel to the direction of compression, the primary retaining portion and the secondary retaining portion being coupled to each other when the first threaded body is engaged with the tapping and being decoupled from each other when the first threaded body of the retaining member is not engaged with the tapping.

[0016] - The anti-rotation member comprises a second threaded body, which is configured to to be engaged with the tapping when the first threaded body is not engaged with the tapping, in order to prevent the rotation of the foot relative to the terminal plate around the central axis by pressing the anti-rotation element against the terminal plate along the direction of compression.

[0017] - The holding system is configured to allow adjustment of a position foot retention, defined in relation to the base and for which the retention system prevents the foot from sliding, among a continuous range of foot positions along the direction of compression, in order to adjust the value of the pressing force applied by the spring.

[0018] - The spring is a compression spring interposed between the base and the next foot the direction of compression.

[0019] The invention also relates to a dimensional compensation system comprising the cartridge as defined above; and the end plate.

[0020] Preferably, the dimensional compensation system further comprises the retaining wall, and wherein the retaining wall comprises an access opening, which is passing through and which is configured to allow the cartridge to be put into the released configuration through the access port, when the base is retained by the retaining wall, making the retaining system accessible through the access port when the base is retained by the retaining wall.

[0021] The invention also relates to a fuel cell comprising: • the dimensional compensation system as defined above, in which: • The cartridge is in a released configuration. • The foot is assembled with the end plate via the assembly means, and • the base is held in the opposite direction to the compression direction by the retaining wall; • a supporting wall, the supporting wall and the retaining wall being fixedly attached to each other, the supporting wall being arranged in the direction of compression relative to the retaining wall; and • the stack of electrochemical cells, which is arranged between the retaining wall and the support wall, bearing against the support wall in the direction of compression, the end plate bearing against the stack in the direction of compression, the cartridge spring applying the pressing force on the stack via the foot assembled with the end plate, in the direction of compression, bearing on the base.

[0022] Preferably, the retaining wall and the support wall belong to a housing of the fuel cell, the stack being received inside the housing, the housing further comprising a longitudinal wall connecting the retaining wall to the support wall.

[0023] The invention also relates to the use of the cartridge as defined above, the use comprising: • an assembly of the foot with the end plate by means of the assembly means; • an application of an initial compressive force on the stack using a pressure element separate from the cartridge, along the direction of compression, while the stack is supported against a support wall along the direction of compression, the end plate is supported against the stack along the direction of compression, the foot is still assembled with the end plate and the cartridge is in prestressed configuration; • a fixing of the retaining wall, so that the supporting wall and the retaining wall are fixedly attached to each other, that the wall the support is positioned in the compression direction relative to the retaining wall, and the cartridge, end plate, and stack are positioned between the retaining wall and the support wall in the compression direction, the retaining wall being fixed while the end plate is still bearing against the stack, the cartridge is still assembled with the end plate, and the cartridge is still in its prestressed configuration; and • a release of the initial compression force and a release of the cartridge configuration, while the retaining wall has been fixed, while the retaining wall holds the base in the opposite direction to the compression direction, the spring, bearing on the base, then applies the pressing force on the stack via the foot and the end plate, following the compression direction.

[0024] According to advantageous, but not mandatory, aspects of the invention, one or more of the following features may be incorporated, taken individually or in any technically feasible combinations:

[0025] - The use further includes, prior to assembling the foot with the terminal plate, a pre-stressed configuration of the cartridge by coupling the primary retention portion with the secondary retention portion, in order to bring the pressing force to a desired value for maintaining the stack in compression;

[0026] - The foot assembly is carried out while the cartridge is in configuration prestressing.

[0027] - The use further includes, while the compression force is being released initial and free configuration of the cartridge were carried out, an anti-rotation device was mounted to prevent rotation of the foot relative to the terminal plate around the central axis.

[0028] - The retaining wall is fixed after the application of the initial compression force, while the initial compression force is still being applied.

[0029] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0030] [Fig-1] [Fig. 1] is a perspective view of a cartridge for a fuel cell, according to an embodiment of the invention, the cartridge being shown in longitudinal section and in a prestressed configuration.

[0031] [Fig.2] [Fig.2] is a perspective view of a fuel cell including several cartridges conforming to that of [Fig. 1], the fuel cell being shown in longitudinal section, the cartridges being in a release configuration.

[0032] [Fig.3] [Fig.3] shows a detail of the longitudinal section of [Fig.2], according to the frame III shown in [Fig.2].

[0033] Figure 1 shows a cartridge 1, which comprises a base 10, a foot 20, a spring 30, and a retaining system 40. As explained below, the cartridge 1 is configured to switch between, that is, to move between, a pre-stressed configuration, shown in Figure 1, and a released configuration, shown in Figures 2 and 3, by means of the retaining system 40. In other words, the retaining system 40 either holds the cartridge 1 in the pre-stressed configuration or is released or decoupled so that the cartridge is in the released configuration. The cartridge 1 has a direction of use, defining a compression direction XI, fixed relative to the foot 20, and directed from the base 10 to the foot 20. The cartridge 1 is geometrically traversed by a central axis X10, parallel to the compression direction XL.

[0034] The cartridge 1 is intended to be integrated into a fuel cell 50, shown in Figures 2 and 3, to compress a stack 51 of electrochemical cells 52 belonging to said fuel cell 50. The outline of the stack 51 is shown schematically in dashed lines in [Fig. 2]. The electrochemical cells are not individually shown for the sake of simplicity.

[0035] Preferably, the cartridge 1 belongs to a dimensional compensation system which includes, in addition to the cartridge 1, an end plate 53, shown in Figures 2 and 3. The end plate 53 is intended to bear against the stack 51 of the fuel cell 50 along the XL direction. Preferably, the dimensional compensation system includes one or more other cartridges 1' to which the description of the cartridge 1 applies, and which contribute to maintaining the stack 51 in compression like the cartridge 1.

[0036] The stack 51 comprises, for example, between two hundred and five hundred cells 52. Each electrochemical cell 52 is, for example, made up of an anode and a cathode, separated by a polymer membrane allowing the passage of protons from the anode to the cathode. During the operation of the fuel cell 50, each anode of the stack 51 is supplied with fuel, for example, dihydrogen, and each cathode of the stack 51 is supplied with an oxidant, for example, oxygen or air.

[0037] To form the stack 51, the electrochemical cells 52 are stacked, i.e. superimposed, according to a stacking direction, which is here parallel to the compression direction XI when the cartridge 1 is integrated into the stack 50. Preferably, when the stack 50 is in operation, for example in a vehicle, the stacking direction and the compression direction XI are approximately horizontal.

[0038] In addition to the stack 51, the fuel cell 50 includes a casing 60. The cartridges 1 serve to maintain the stack 51 in compression along the compression direction XI during the use of the fuel cell 50, preferably throughout the life of the fuel cell 50.

[0039] The housing 60 surrounds and protects the stack 51 and thus forms an advantageously sealed enclosure. The housing 60 comprises a transverse wall 61 mentioned above, referred to as the "retaining wall", a longitudinal wall 62 and a transverse wall 63 mentioned above, referred to as the "support wall".

[0040] Here, walls 61 and 63 are perpendicular to direction XI, and longitudinal wall 62 is parallel to direction XL. Longitudinal wall 62 is a peripheral wall that surrounds the stack 51 and connects walls 61 and 63 to each other by being attached to their respective perimeters. Stack 51 is also arranged between walls 61 and 63, which are preferably substantially planar, with wall 63 oriented in direction XI relative to wall 61. Overall, walls 61, 62, and 63 are arranged so that the housing 60 has a general parallelepiped shape.

[0041] In the present example, the retaining wall 61 and the supporting wall 63 are removable relative to the longitudinal wall 62. Alternatively, the retaining wall 61 may be permanently fixed or form a single piece with the longitudinal wall 62, such that the walls 61 and 62 form a subassembly attached to the wall 63, which is removable relative to this subassembly. Alternatively, the walls 62 and 63 may be permanently fixed or form a single piece, while the wall 61 is removably fixed to this subassembly. Whatever the situation, it is advantageously provided that the wall 61 is removable with respect to the wall 63, either for example in that the wall 61 is removable with respect to the wall 62, or in that the wall 62 is removable with respect to the wall 63, or both at the same time, as in the present example.

[0042] The support wall 63 here serves as a fixed end plate for the stack 51, in that the stack 51 is supported, along the direction XI, against the support wall 63, without the interposition of an elastic element for dimensional compensation. However, it could be envisaged that the stack 51 includes a separate fixed end plate, through which the stack 51 would be supported against the support wall 63. As shown in [Fig. 2], preferably, the support wall 63 has openings through which connectors, not shown, can be passed, intended to be connected to fluid circulation lines, thus allowing the stack 51 to be supplied with fuel, oxidizer, a possible cooling fluid, and the removal of reaction products if any.

[0043] The retaining wall 61, which belongs to the pile 50 once mounted, can be considered as belonging to the dimensional compensation system, in particular before its integration into the pile 50.

[0044] The base 10 of the cartridge 1 has a proximal end 11, a distal end 12, a peripheral wall 13, and preferably a central conduit 14, which are fixed relative to each other, for example, by being all one piece. The axis X10 passes successively through the ends 11 and 12, with the end 12 being in the direction XI relative to the end 11. The wall 13 surrounds the axis X10 and connects the ends 11 and 12. The wall 13 is preferably cylindrical with a circular base, centered on the axis X10. The central conduit 14, if provided, advantageously passes through the base from the end 11 to the end 12, being centered on the axis X10.

[0045] The retaining wall 61 comprises an inner face 69 and an outer face 66 opposite and perpendicular to the direction XL. The lower face 69 is directed along the direction XL. The outer face 66 advantageously faces the outside of the housing 60 and is opposite the stack 51, while the inner face 69 faces the inside of the housing 60 and faces the stack 51.

[0046] As shown in [Fig.3], each cartridge 1 is configured to be retained by the retaining wall 61 by bearing against the retaining wall 61 in the opposite direction of XI, via the base 10. In particular, the cartridge 1 is retained in that the proximal end 11 of the base 10 bears against the inner face 69, in the opposite direction of XL. If several cartridges are provided, they are then distributed over the surface of the retaining wall 61.

[0047] Preferably, the foot 20 comprises a support pad 22, a tubular crown 29 and a shaft 21.

[0048] The tubular ring 29 is coaxial with the central axis X10. The tubular ring 29 is in the shape of a tube with a circular cross-section. The tubular ring 29 extends from the pad 22, in particular from a peripheral edge of the pad 22, in the opposite direction to XL. The base 10 is preferably received inside the tubular ring 29, which surrounds the base 10.

[0049] The support pad 22 is advantageously discoidal in shape, centered on the axis X10, and advantageously has an orifice in its center through which the axis X10 passes. The support pad 22 is fixed here relative to the shaft 21 and the ring 29, preferably all three being monoblocs, and is formed in the direction XI relative to the shaft 21 and the ring 29. Preferably, the support pad 22 has a diameter greater than that of the peripheral wall 13, so that the tubular ring 29, rising from the peripheral edge of the pad 22, extends around the base 10.

[0050] The shaft 21 is coaxial with the central axis X10. The shaft 21 is in the shape of a tube with a circular cross-section. The shaft 21 extends from the pad 22, in the opposite direction to XL. The shaft 21 is then coaxial with the ring 29 and is arranged inside the ring 29, being connected to the ring 29 by the pad 22. The shaft 21 forms a conduit coaxial with the axis X10, which advantageously passes through the foot 20 from one side to the other.

[0051] The foot 20 and the base 10 slide relative to each other, along the direction XL. To guide this sliding, preferably, the tubular ring 29 forms an internal wall, which cooperates radially with the peripheral wall 13 of the base 10. Preferably, the foot 20 and the base 10 are assembled with each other according to the principle of a sliding pivot joint along the axis X10.

[0052] The shaft 21 is received in a conduit 18 of the base 10, belonging to the central conduit 14 and opening at the distal end 12 of the base 10. The shaft 21 enters the conduit 14 through its end 12. When the sliding between the base 10 and the foot 20 is guided by the ring 29, a significant radial clearance is advantageously provided between the shaft 21 and the conduit 18. Alternatively, a smaller radial clearance can be provided so that the sliding is guided by radial cooperation of the shaft 21 with the conduit 18. In this case, a significant radial clearance can optionally be provided between the ring 29 and the wall 13 of the base 10, so that the sliding is guided only by the shaft 21 and not by the ring 29.

[0053] In the present example, regardless of the position of the foot 20 relative to the base 10 for its sliding, the support pad 22 is arranged in the direction XI relative to the distal end 12 of the base 10, and thus forms a distal end of the cartridge 1. Alternatively, the crown 29 and / or the shaft 21 could be provided to protrude from the support pad 22 in the direction XI and thus constitute the distal end of the cartridge 1.

[0054] The assembly means 17 is designed to allow the foot 20 to be assembled with the end plate 53, through which the cartridge 1 is intended to maintain the stack 51 in compression along the XL direction. The end plate 53, thus assembled, becomes fixed to the foot 20, or at least captures the foot 20 parallel to the XL direction. Depending on the situation, the assembly means 17 constitutes a fastener, a hook, or a connection for assembling the foot 20 with the end plate 53, which preferably includes additional features with the assembly means 17. The assembly means 17 allows the foot 20 to be assembled with the end plate 53 when they were initially unassembled. Preferably, the assembly means 17 also allows the foot 20 and the end plate 53 to be disassembled when they were assembled.

[0055] Preferably, the assembly means 17 forms an external thread integral with the foot 20. Here, the assembly means 17 and the foot 20 form a single piece, the external thread being formed as part of the foot 20. The external thread is advantageously coaxial with the central axis X10. The external thread advantageously extends around the foot 20, in particular around the pad 22 and around the shaft 21, for example by being supported by the tubular ring 29. The external thread of the assembly means 17 is configured to engage with a corresponding internal thread 65, belonging to the end plate 53, to assemble the foot 20 with the end plate 53.

[0056] Alternatively, the assembly means 17 is a bayonet fitting, intended to be coupled with a complementary base, belonging to the terminal plate 53.

[0057] Alternatively, the assembly means 17 includes screws or other fasteners for fixing the foot 20 to the end plate 53.

[0058] Preferably, the base 10 includes an actuating head 16, formed at its proximal end 11. The actuating head 16 is intended to be actuated by a person, preferably using a tool, or by a machine, to rotate the cartridge 1 about the axis X10, in order to allow the external thread of the assembly means 17 to engage in the internal thread of the end plate 53. For example, as illustrated, the actuating head 16 is formed by a hexagonal end centered on the axis X10, to be actuated by a hex key. More specifically, in the illustrated example, it is in particular a pressing force F30, applied by the spring 30 when the cartridge 1 is in the pre-loaded configuration, that allows the rotational torque applied to the actuating head 16 to be transmitted to the assembly means 17.

[0059] When the foot 20 is assembled with the end plate 53 via the assembly means 17, the foot 20 is designed to bear, along the direction XI, against the end plate 53 to which the foot 20 is assembled, either directly or via the assembly means 17.

[0060] In the present embodiment, the foot 20 is supported by means of the assembly means 17, which bears along the direction XI against the internal thread 65, as explained below. In other embodiments, when the foot 20 is directly supported, it is preferably achieved by means of the support pad 22, which then advantageously forms the distal end of the cartridge 1. The support pad 22 then forms, for example, a discoidal axial surface, rotated in the direction XI, to bear along the direction XI against the surface to be pressed.

[0061] The spring 30 bears against the base 10 to apply a pressing force F30 on the foot 20 along the direction XI, by virtue of the elasticity of the spring 30. Preferably, the spring 30 is a spring that acts in compression, along the direction XL

[0062] The spring 30 consists of at least one spring washer, or, preferably, a stack of spring washers, sometimes called Belleville washers. The spring washers are stacked along the XI direction and centered on the X10 axis. A spring 30 made of spring washers has the advantage of repeating the force F30, particularly compared to a helical spring. Furthermore, the use of spring washers, depending on their characteristics, advantageously reduces the size of the compression cartridge, thus increasing its compactness.

[0063] The spring 30, consisting of spring washers, is preferably configured so that the value of the pressing force F30 is constant, or varies little, over a range of spring 30 elongation values. Preferably, when the cartridge 1 is in its preloaded configuration and when the cartridge 1 is in its released configuration by being installed in the stack 50, the elongation value of the spring 30 is within the range where the force F30 depends little on, or is not affected by, a variation in the elongation value. Such an operating range, known as linear, is more easily achieved with a spring washer than with a helical spring.

[0064] Preferably, spring washers are used, each having a ratio R between 1.1 and 1.3, preferably approximately equal to 1.2, the ratio R being calculated as follows:

[0065] Ratio R = [washer height - washer thickness] / washer thickness

[0066] The "washer height" is a measurement of the spring washer along the X10 axis, when the spring washer is undeformed, from one end of the spring washer to the other. The "washer thickness" is a measurement of the thickness of the material constituting the washer along the X10 axis.

[0067] Alternatively, the spring 30 could be provided for to be a helical spring, centered on the axis X10, rather than a spring with washers.

[0068] For example, in order to apply the force F30 to the foot 20 while bearing on the base 10, the spring 30 is interposed, parallel to the direction XI, between the distal end 12 of the base 10 and the support pad 22. Thus, the spring bears on the support pad 22. The end 12 and the pad 22 respectively form opposing bearing walls, each receiving a respective end belonging to the spring 30. The spring 30 is, for example, arranged around the shaft 21 and inside the ring 29.

[0069] Radially with respect to the axis X10, the spring 30 advantageously has a radial footprint smaller than that of the base 10, in particular at the wall 13, and also, in the example, than that of the support pad 22. In other words, radially, the spring 30 does not protrude radially from either the foot 20 or the base 10.

[0070] Preferably, the holding system allowing the cartridge 1 to evolve between the pre-stressed configuration and the released configuration is constructed as follows.

[0071] The conduit 14 forms an axial shoulder 41, located at the proximal end 11, or between the end 11 and the conduit 18, and rotated in the opposite direction to XL. The shoulder is centered on the axis X10. The shoulder 41 is, for example, formed on an internal neck belonging to the conduit 14. The axial shoulder 41 forms a primary retention portion belonging to the retention system 40 and being integral with the base 10.

[0072] Preferably, a tapped hole 42, i.e., an internal thread, is provided in the barrel 21, at least for a portion of the barrel in the direction of the base 10. In the present example, the tapped hole 42 even extends along the entire length of the barrel 21. The tapped hole 42 is located along the axis of the shoulder 4L. The tapped hole 42 forms a secondary retaining portion belonging to the retaining system 40 and being integral with the foot 20. According to this example, the external thread constituting the assembly means 17 is arranged around the secondary portion, which gives the cartridge 1 good compactness.

[0073] Preferably, the retaining system 40 further comprises a screw 43, with a head 44 and a threaded body 45. The screw 43 advantageously constitutes a retaining element belonging to the retaining system 40 and which interacts with the primary retaining portion and the secondary retaining portion.

[0074] In the pre-stressed configuration, the screw 43 is received in the central channel 14 and in the threaded hole 42, as shown in [Fig. 1]. The screw 43 ensures mutual coupling of the primary retaining portion with the secondary retaining portion, in that the screw 43 bears, along the direction XI, against the shoulder 41, via the head 44, and in that the threaded body 45 is engaged in the threaded hole 42 by means of a screw-nut connection. The screw-nut connection is preferably non-reversible, in the sense that the force imposed by the spring 30 does not allow for relative rotation between the screw 43 and the foot 20. In the pre-stressed configuration shown in [Fig. 1], the threaded body 45 is oriented along the compression direction XI, while the head 44 is oriented in the opposite direction, and the screw 43 is advantageously coaxial with the axis X10.This mutual coupling of the primary retaining portion with the secondary retaining portion via the retaining member means that the retaining system 40 prevents the foot 20 from sliding relative to the base 10, in the direction XI, despite the pressing force F30 applied by the spring 30 on the foot 20 while the spring bears against the base 10. In the present case, the engagement of the threaded body 45 in the tapped hole 42 makes the screw 43 fixed to the foot 20, while, at the same time, the head 44 is held against the shoulder 41 of the base in the compression direction XI, due to the force F30, which is transmitted. to the screw 43 via the foot 20. The pre-stressed configuration thus allows the spring 30 to remain pre-stressed, the spring 30 applying the force F30.

[0075] Preferably, the retaining system 40 allows adjustment of the position of the foot 20 relative to the base 10 along the compression direction XI, referred to as the "retaining position," for which the retaining system 40 prevents the foot 20 from sliding. Indeed, for example, by tightening or loosening the screw 43 in the threaded hole 42, the retaining position in which the foot 20 is held by the screw 43 is changed. Tightening the screw brings the foot 20 closer to the base 10, while loosening it moves the foot 20 further away from the base 10.The holding position in which the foot 20 is held by the holding system 40 can therefore be chosen from a continuous range of foot 20 positions along the XL direction. In the present example, this continuous range corresponds to the screw travel of the screw 43 in the threaded hole 42, parallel to the XL direction. To perform this adjustment, a press can also be used to avoid manipulating the screw 43 under the stress of the spring force F30. For example, it is possible to position the cartridge 1 under the press to compress the spring 30, and then simultaneously adjust and fix the position of the foot 20 relative to the base 10 without the stress of the spring force F30, the latter being compressed by the press. This facilitates the adjustment operation and limits the risk of breakage of the screw 43.

[0076] Preferably, whether the spring 30 has spring washers or not, the spring 30 is designed so that the value of the pressing force F30 of the spring 30 does not vary, or varies very little, over a range of spring 30 elongation values, this range having a certain extent around the elongation value obtained when the cartridge 1 is in the preloaded configuration. Preferably, the extent of this range covers the dimensional variation of the stack 50 during operation. This can notably be achieved by a spring with spring washers as explained previously. It is then advantageously provided that, once the cartridge 1 is mounted in the stack 50 and is in the released configuration, the spring 30 is within this range of elongation values, so that the value of the pressing force F30 does not vary, or varies very little, despite the dimensional variations of the stack 51.Therefore, the pressing force F30 is not adjustable by changing the position of the foot 20, and is adjusted by changing or replacing the spring 30. For example, the number of spring washers constituting the spring 30 can be changed to vary the force F30 obtained and / or their geometric characteristics (thickness, inner / outer diameter, height).

[0077] Alternatively, whether the spring 30 has spring washers or not, the spring 30 is configured so that the value of the pressing force F30 that it produces depends on an elongation value of the spring 30, measured along the axis XI, to allow a The value of the pressing force F30 is adjusted by adjusting the elongation value. "Elongation" refers to the change in length of the spring 30, measured from one end of the spring 30 to the other parallel to the direction XI. In the case of a compression spring, the force F30 increases when the length of the compression spring is reduced. Thus, the force F30 increases for a negative elongation value. Therefore, adjusting the holding position of the foot 20 advantageously allows for adjusting the value of the pressing force F30, since each holding position corresponds to a distinct elongation value for the spring 30, which determines the value of the pressing force F30. In a preloaded configuration, the value of the force F30 applied by the spring 30 to the foot can thus be selected by adjusting the holding system 40.

[0078] To put the cartridge 1 in its released configuration, the primary retaining portion is decoupled from the secondary retaining portion, preferably by removing the retaining element. In this example, the screw 43 is removed, in particular by disengaging the threaded body 45 from the threaded hole 42 by unscrewing it. Figures 2 and 3 show the cartridge 1 in its released configuration, where the screw 43 is absent. In the released configuration, the foot 20 is therefore allowed to slide relative to the base 10, particularly under the action of the force F30, because the foot 20 is no longer retained by the retaining system 40. The foot 20 is then able to transmit the pressing force F30 to the end plate 53 to which the foot 20 is attached via the assembly means 17, along the compression direction XI, when the base 10 is otherwise retained in the opposite direction to XL.

[0079] Preferably, one end of the screw 43, located at the level of the head 44, has a recess 46, for example a star-shaped recess, so that a person, using a tool, or a machine, can actuate the screw 43 in rotation around the axis X10.

[0080] In summary, the cartridge 1 comprises two configurations, each defined by design. In the first configuration, known as the "pre-stressed configuration," the cartridge 1 is configured for safe handling outside of a fuel cell, notably thanks to the retaining system 40 which maintains the compressed spring 30. This pre-stressed configuration is stable. In the second configuration, known as the "released configuration," the cartridge 1 is configured to apply the pressing force F30, preferably predetermined, to the end plate 53, which is to be pressed against the stack 51 of electrochemical cells 52 of the fuel cell 50. When the cartridge 1 is fitted to the fuel cell 50, this released configuration is stable.

[0081] As can be seen in Figures 2 and 3, the terminal plate 53 is intended to be assembled with the cartridge 1, as well as with any other cartridge(s) 1'. Under the action of the compressive force F30 of each cartridge 1 and 1' in the released configuration and retained by the retaining wall 61 of the stack 50 in the opposite direction to XI via the base 10, the end plate 53 is designed to bear against one end of the stack 51 along the direction XI, in order to maintain the stack 51 in compression along the direction XI, while the stack 51 is supported against the support wall 63 along the direction XI, at its opposite end. The end plate 53 can therefore be described as a movable end plate 53, in that it is movable relative to the support wall 63.

[0082] The terminal plate 53 comprises an assembly side 54 and an opposing inner face 55.

[0083] The assembly side 54 is directed in the opposite direction to the XL direction. The cartridges 1, 1' are arranged on the assembly side 54. The inner face 55 is formed on the opposite side, by being turned along the XL direction. The inner face 55 is intended to bear directly against the stack 51, preferably directly against one of the cells 52.

[0084] On the assembly side 54, the end plate 53 preferably includes, for each cartridge 1, 1', the necessary provisions for assembly with the assembly means 17. For example, when the assembly means 17 is an external thread as illustrated, the end plate 53 includes, for each cartridge 1, 1', a respective internal thread 65, preferably formed inside a base 57. For example, the base 57 protrudes from the assembly side 54 in the opposite direction to XL. Preferably, the end plate 53 forms the base 57, the internal thread 65, the assembly side 54, and the internal face 55 in a single piece. If several cartridges are provided, they are preferably distributed over the surface of the end plate 53 when assembled with the end plate 53.

[0085] When several cartridges 1,1' are provided, they can be individually assembled with the end plate 53, independently of each other, via their respective assembly means 17. Thus, each cartridge 1,1' can be assembled with the end plate 53, via its individual assembly means 17, while one or more other cartridges are already assembled with the plate 53.

[0086] Advantageously, by screwing or unscrewing the thread 17 into the thread 65, the foot 20 can be selectively brought abutting against the end plate 53 in the direction XI while the foot 20 is assembled by screwing the thread 17 into the thread 65, or it can be positioned at a distance from the end plate 53 while the foot 20 is still assembled by screwing the thread 17 into the thread 65. Thus, while the foot 20 remains assembled, its position relative to the plate 53 following The axis XI can be modified. Preferably, under the effect of screwing and stopping, the foot 20 and / or the thread is clamped parallel to the direction XI, preventing the foot 20 from pivoting relative to the end plate 53 around the axis X10. The foot 20 and the plate 53 are then immobilized relative to each other, with all degrees of freedom.

[0087] Preferably, the cartridge 1 includes a member 49, which advantageously is provided to compensate for axial play in the assembly means 17 in the case where the screwing of the thread 17 is carried out without the foot 20 being butted against the plate 53 in the direction XL. It can be provided that this same member 49 then immobilizes the degree of freedom in rotation of the foot 20 with respect to the plate 53 around the axis X10 and thus constitutes an anti-rotation member.

[0088] This element 49 can also be provided in the case where the screwing of the thread 17 is carried out with the foot 20 abutted against the plate 53 in the direction XL.

[0089] Preferably, the element 49 is removable with respect to the foot 20, the base 10, the retaining system 40 and the spring 30. The anti-rotation element 49 is configured to be mounted, for example, on the secondary retaining portion 42 or on the foot 20. When the external thread 17 is engaged in the internal thread 65 of the end plate 53, the element 49 thus mounted takes up the axial play and, preferably, prevents rotation of the foot 20 relative to the end plate 53 around the central axis X10.Therefore, in the case where the member 49 serves to prevent rotation, the foot 20 and the end plate 53 are fixed relative to each other, since the engagement of the assembly means 17 ensures axial and radial immobility of the foot relative to the plate 53, and the engagement of the anti-rotation member 49 takes up any axial play and eliminates the last degree of rotational freedom of the foot 20. Preferably, the assembly of the member 49 can only be carried out when the retaining system 40 is in the released configuration.

[0090] For example, the organ 49 advantageously forms a screw. Accordingly, the member 49 includes a threaded body 48, which is configured to engage with the tapped hole 42 when the threaded body 45 of the retaining member 43 is not engaged with the tapped hole 42, in order to compensate for axial play and preferably to prevent rotation of the foot 20 relative to the end plate 53 around the central axis X10, by bearing the member 49 against the end plate 53 along the compression direction XL. In other words, the member 49 is installed in place of the retaining member 43. More precisely, it is provided that, by screwing the member 49 into the tapped hole 42, a distal end 47A of the member 49 comes into tight contact along the direction XI against the assembly side 54 of the plate 53, thus preventing rotation of the foot 20.For this purpose, the distal end 47A protrudes beyond the foot 20, in particular beyond the skate 22 along the XI direction, emerging from the foot 20 at a distal end of the shaft. 21. Preferably, as with the retaining member 43, the member 49 can be inserted into the cartridge 1 at its proximal end 11, via the central conduit 14, to be engaged in the threaded hole 42. Once engaged, the member 49 can be actuated through the base via the central conduit 14. To this end, opposite the distal end 47A, the member 49 includes a proximal end 47B forming a recess, for example a hexagonal or star-shaped recess, allowing the member 49 to be rotated about the axis X10 by means of a tool or machine. This recess opens in the opposite direction to XI into the inside of the barrel 21 or the central conduit 14, for access.

[0091] This arrangement is advantageous because the secondary retaining portion 42 serves both to ensure the maintenance in the pre-stressed configuration of the cartridge 1 by cooperation with the retaining member 43, and, in the absence of the retaining member 43 leading to the released configuration, to ensure the compensation of axial play and / or the anti-rotation of the foot 20 with respect to the terminal plate 53, by cooperation with the member 49.

[0092] Preferably, when the dimensional compensation system is not yet integrated into the fuel cell 50, the cartridges 1,1' assembled with the terminal plate 53 form, with said plate 53, a solid sub-assembly.

[0093] Preferably, for each cartridge 1 to be fitted, the retaining wall 61 provides a respective access opening 64, which passes completely through the retaining wall 61, parallel to the compression direction XI. Each opening 64 connects the faces 66 and 69 to each other. If several cartridges are provided, the openings 64 are distributed over the surface of the retaining wall 61, at locations corresponding to those of the cartridges.

[0094] When the cartridge 1 is retained by the retaining wall 61, the base 10 of said cartridge 1 is arranged so that the proximal end 11 opens into the orifice 64, or, at the very least, is accessible beyond the retaining wall 61 through the orifice 64. For example, the axis X10 passes through the orifice 64. Preferably, the cartridge 1 is aligned with the orifice 64. In other words, the base 10 can be accessed from the face 66 through the access orifice 64.

[0095] In practice, the orifice 64 provides access to the base 10 to put the cartridge 1 in the released configuration when the cartridge was in the pre-stressed configuration, in that the retaining member 43 is actuated through the orifice 64, and, preferably, can be extracted through the orifice 64. Similarly, the member 49, if provided, can be inserted into the cartridge 1 and actuated through the retaining wall 61 via the orifice 64.

[0096] More specifically, when the base 10 is retained by the retaining wall 61, it is envisaged that the cartridge 1 can, from the outer face 66, be put into The cartridge 1 can be released from its pre-tensioned configuration if it was in the pre-tensioned configuration, and / or be put into the pre-tensioned configuration if it was in the released configuration. For this purpose, for example, it is provided that, when the cartridge 1 is in the pre-tensioned configuration and received in the orifice 64, the head 44 of the screw 43, and in particular the recess 46, is accessible from the proximal end 11 of the base 10, and therefore from the outer face 66. The screw 43 can thus be actuated from outside the housing 60. In particular, the screw 43 can be removed via the opening of the conduit 14 on the end 11 side, to put the cartridge 1 into the released configuration.Conversely, when the cartridge 1 is in the released configuration, the screw 43 can be inserted into the conduit 14, through the opening of the conduit 14 at the end 11, and then the screw 43 can be rotated from the end 11 to engage the threaded body 45 with the thread 42, thus achieving the pre-stressed configuration, for example, for opening the casing 60 of the fuel cell. Maintenance of the fuel cell 50 is then facilitated.

[0097] Preferably, the actuation of screw 43 is intended solely to switch cartridge 1 between the preloaded and released configurations. Alternatively, screw 43 may be actuated to adjust the value of force F30 when cartridge 1 is in the preloaded configuration.

[0098] Similarly, when the base 10 is retained by the retaining wall 61, it is provided that the foot 20 can be immobilized against rotation relative to the end plate 53, and / or that the axial play can be taken up by mounting the component 49, or that this play can be restored and the rotation released by removing the component 49. For this purpose, for example, it is provided that the proximal end 47B of the component 49, and in particular its indentation, is accessible from the proximal end 11 of the base 10, and therefore from the outer face 66. The component 49 can thus be actuated from outside the housing 60. In particular, the component 49 can be inserted via the orifice 64 and the opening of the conduit 14 on the end 11 side, when the cartridge 1 is in the released configuration, and then the component 49 can be rotated from the end 11 to engage the threaded body 48 with the tapping 42 and thus immobilize the foot 20 in rotation.

[0099] Preferably, when the cartridge 1 is retained by the retaining wall 61, it is not attached to the retaining wall 61, but merely supported in the opposite direction to XI, without any other support. In particular, the orifice 64 does not include any means for attaching, or even assembling, the cartridge 1 with the wall 61, for example, no thread intended to cooperate with the cartridge 1. In particular, when the cartridge 1 is retained by the retaining wall 61, the cartridge 1 is not supported against the retaining wall 61 radially with respect to the XL direction. In particular, the orifice 64 is not used for centering the cartridge 1, which may, depending on the mounting, not be perfectly coaxial with the orifice 64. In particular, when the cartridge 1 is retained by the retaining wall 61, the cartridge 1 is not supported against the retaining wall 61 along the direction XI. In particular, the retaining wall 61 does not capture the cartridge 1, the cartridge 1 being captured only by being interposed between the retaining wall 61 and the stack 51.

[0100] Preferably, when the cartridge 1 is retained by the retaining wall 61, the cartridge is positioned beyond the wall 61 in the direction XI, except possibly for the proximal end 11 and / or part of the retaining system 40, which is received in the orifice 64. Advantageously, the cartridge 1 is not provided to protrude from the wall 61 through the orifice 64 in the opposite direction to XI. In any case, when the cartridge 1 is retained by the retaining wall 61, the foot 20 advantageously protrudes from the wall 61, in particular from the inner face 69, in the direction XI.

[0101] Optionally, the orifice 64 provides access to the actuating head 16 through the retaining wall 61, in order to actuate the cartridge 1 in rotation around the axis X10 while the retaining wall 61 is interposed between the cartridge 1 and the operator or the machine which is to rotate the cartridge 1. This rotational actuation is preferably carried out while the cartridge 1 is not yet in contact with the retaining wall 61, in order to bring the cartridge 1 in contact with the retaining wall 61, the rotation being carried out in the direction of unscrewing the thread 17, moving the cartridge 1 away from the end plate 53 without detaching it.

[0102] Preferably, each orifice 64 is designed to be closed by a plug, not shown, attached along direction XI to one end of the orifice 64 on the outer face 66, while the cartridge 1 is retained by the wall 61. Preferably, the orifice 64 has an internal thread for assembling the plug to close the orifice 64, this thread not being designed to cooperate with the cartridge 1 itself. Thus, during the operation of the battery 50, the orifice 64 is sealed so that the housing 60 forms a sealed enclosure.

[0103] Preferably, the orifice 64 is shaped so that the cartridge 1 cannot be traversed, in particular so that the foot 20 cannot be traversed, when attempting to insert the cartridge 1 into the orifice 64 along the direction XI, from the outer face 66. Preferably, the orifice 64 is shaped so that the cartridge 1 cannot be traversed, in particular so that the base 10 cannot be traversed, except possibly by the proximal end 11, when attempting to insert the cartridge 1 into the orifice 64 in the opposite direction to XI, from the inner face 69. In practice, the orifice 64 is narrower than the cartridge 1 and is intended to be traversed only for the actuation of the cartridge through the wall 61, without being traversed by the cartridge 1 itself.

[0104] During the use of the stack 50, while the stack 51 is likely to expand and contract parallel to the direction XI, the base 10 remains held against the retaining wall 61 in the opposite direction to XI under the action of the spring 30 of the cartridges 1, 1' in the released configuration. The base 10 slides, if necessary, relative to the foot 20 to accommodate this expansion or contraction. The foot 20 remains fixed relative to the end plate 53, being assembled to the plate 53 via the assembly means 17. The retaining wall 61 is fixedly attached to the opposite support wall 63, via the longitudinal wall 62. As the stack 51 comes to rest against the wall 63 along the direction XI, the stack 51 is compressed between the feet 20 of the cartridges 1 and 1' and the support wall 63, and takes in compression the pressing force F30 applied respectively by the springs 30 of each cartridge 1 and 1'.

[0105] Other elements can be interposed in the stack 51, between the plate 53 and the wall 63, for example a current collector plate and / or an insulation plate.

[0106] Below is described a method of using the compensation system described above, and in particular the cartridge 1. This use can also be seen as a method of manufacturing the fuel cell 50, or as a method of putting and maintaining in compression the stack 51.

[0107] Preferably, while the cartridge 1 is not yet assembled to the terminal plate 53 nor received in the housing 60 or against the stack 51, it is planned on the one hand to prepare said cartridge 1 and the compensation system, and on the other hand to prepare the stack 51 and the housing 60.

[0108] To prepare the stack 51 and the housing 60, the stack 51 is placed against the support wall 63 along the compression direction XL. For this purpose, for example, the support wall 63 is positioned horizontally and the cells 52 are stacked.

[0109] Independently of the preparation of the housing 60, the cartridge 1 is prepared. This step can, in particular, be carried out in parallel with the preparation of the housing 60. To prepare the cartridge 1, once the base 10, the foot 20, the spring 30, and the system 40 have been supplied or manufactured, they are assembled. This includes positioning the spring 30 so that it bears against the base 10 in the opposite direction to the compression direction XI and against the foot 20 in the direction XL. At this stage, the cartridge 1 is in a released configuration, so that the foot 20 is free to slide relative to the base 10, while still being subjected to the pressing force F30 of the spring 30.

[0110] Next, while holding the base 10 in the opposite direction to XI, a force is applied to the foot 20 in the opposite direction to XI, for example using a press, to slide the foot 20 towards the base 10 and thus put the spring 30 under stress, that is to say, in this case, under compression. The value of the force The force applied to the foot 20 at this instant is preferably calibrated to correspond to the value of the compressive force F30 that the cartridge 1 is intended to apply later to the stack 51, when the cartridge 1 is integrated into the stack 50 in its released configuration. Once the desired force is reached, the cartridge 1 is placed in a prestressed configuration, which prevents the foot 20 from sliding relative to the base 10 and fixes the value of the compressive force F30 to the value of the force that was applied in the opposite direction to the foot 20. For example, the value of the compressive force F30 within the cartridge 1 in the prestressed configuration is expected to be between two and three kilonewtons, if only one cartridge 1 is used. If there are several cartridges, it is advantageous to divide this value by the number of cartridges used to maintain the stack 51 in compression.

[0111] In particular, to put the cartridge 1 in the pre-stressed configuration, the screw 43 is inserted into the channel 14 until the threaded body 45 reaches the tapped hole 42. The screw 43 is then screwed in, here by actuating the recess 46. This actuating leads to the screwing of the threaded body 45 into the tapped hole 42 until the head 44 comes to rest, along the direction XI, against the shoulder 41. The screw 43 then prevents the foot 20 from sliding relative to the base 10 along the direction XI, so that the base 10, the foot 20 and the retaining system 40 hold the spring 30 pre-stressed, with the desired value for the pressing force F30. Being able to adjust the pressing force F30 before installing the spring 30 in the stack 50 makes adjustment easier and more precise.

[0112] If it is planned to install other cartridges 1' for the stack, as is the case for the present example, they are prepared in the same way as cartridge 1, in order to obtain a desired value for their respective pressing force F30.

[0113] Once the cartridge 1 is in the prestressed configuration, as well as any other cartridges 1', the compensation system is prepared. This is done prior to the integration of the compensation system into the stack 50, in particular prior to the bearing of the end plate 53 against the stack 51 and before the cartridge 1 is retained by the wall 61. The preparation of the compensation system can be carried out independently of the preparation of the casing 60 and the stack 51.

[0114] To prepare the compensation system, the foot 20 of the cartridge 1 is assembled with the end plate 53, using the assembly means 17. In practice, to perform this assembly, the external thread 17 is engaged in the internal thread 65, rotating the cartridge 1 around the axis XI relative to the plate 53. The rotation of the cartridge 1 is preferably carried out via the actuating head 16. Preferably, the cartridge 1 is thus rotated until the foot 20 comes to rest against the plate 53 in the direction XL. This restraint advantageously takes place at the level of the support pad 22. If necessary, the same is done for the other cartridges 1', until all the cartridges 1' are assembled with the terminal plate 53.

[0115] Once the cartridge 1 is thus assembled with the end plate 53, as well as any other cartridge 1', and the stack 51 is ready, the end plate 53 carrying the cartridge(s) 1,1' is placed against the stack 51 along the direction XL. The stack 51 is then interposed between the end plate 53 and the support wall 63, parallel to the direction XL. In practice, the placement of the end plate 53 consists of stacking the end plate 53 on the stack 51 already stacked on the support wall 63.

[0116] Alternatively, the assembly of the cartridge 1 in prestressed configuration with the plate 53 via the assembly means 17 is carried out while the plate 53 is already in support against the stack 51 along the direction XI, but before the application of the initial compressive force F70 mentioned below.

[0117] Alternatively, the prestressing configuration of the cartridge 1 is carried out while the cartridge 1 is already assembled with the end plate 53 via the assembly means 17, but before the end plate 53 is in contact with the stack 51.

[0118] Once the stack 51 is supported against the support wall 63, and the end plate 53 is supported against the stack 51 with the cartridge(s) 1, 1' in prestressed configuration and assembled with the end plate 53, an initial compressive force F70 is applied to the stack 51 using a press 70, or any other pressing device separate from the compensation system and the cartridge 1 itself. The press 70 and the force F70 are schematically shown in [Fig. 3]. Although [Fig.3] shows cartridge 1 already held by wall 61, cartridge 1 in free configuration and member 49 already mounted, it should be considered that, when the force F70 is applied, cartridge 1 is not yet held by wall 61, which is not fixed to wall 62, cartridge 1 is in prestressed configuration and member 49 is not yet mounted.

[0119] In practice, to apply the force F70 to the stack 51, it is advantageous to apply the force F70 via the end plate 53. For this purpose, the end plate 53 preferably comprises one or more application surfaces 72, facing in the opposite direction to XI and formed on the assembly side 54, against which support legs 71 belonging to the press 70 bear in the direction XI to apply the force F70 in a distributed manner. The application surfaces 72 are preferably distributed over the surface of the plate 53, between the sockets 57 forming the threads 65, and therefore, between the cartridges 1, 1'.

[0120] If only one cartridge 1 is to be fitted to the pier 50, it is advantageously assumed that the value of the initial compressive force F70 is equal to or slightly greater than the value of the force F30 contained in the cartridge 1 in its prestressed configuration. If, in addition to the cartridge 1, other cartridges 1' are to be fitted to the pier 50, it is advantageously assumed that the value of the initial compressive force F70 is equal to or slightly greater than the sum of the values ​​of all the cumulative forces F30 contained in the cartridges 1 and 1' in their prestressed configuration.

[0121] Before the application of the force F70, it may occur that the stack 51, in an uncompressed state, presents an obstruction along the direction XI which opposes the placement of the wall 61. In particular, the stack 51 and the compensation system protrude from the wall 62. In this case, it is advantageously provided that the application of the force F70 by the press 70 or the pressing member is carried out through the retaining wall 61, while said wall 61 is not yet fixed to the wall 63 via the wall 62. In particular, the wall 61 is positioned at a distance from the wall 62, preferably at a distance from the cartridges 1, 1', in the opposite direction to XI, with the orifices 64 in alignment with the corresponding cartridges 1, 1', i.e. through which their respective axis X10 passes. For the application of the force F70, it is provided for example that the retaining wall 61 has secondary orifices 67 which pass through it parallel to the direction XI.These orifices 67 are distinct from the orifices 64. The secondary orifices 67 are aligned along the direction XI with the surfaces 72. The support legs 71 are then passed through the orifices 67 along the direction XI, to apply together the force F70 on the stack 51, via the plate 53, through the wall 61 which is not yet attached to the wall 63, here via the wall 62.

[0122] Applying the force F70 produces a compressive deformation of the stack 51, reducing its size along the direction XI and thus allowing the wall 61 to be attached to the wall 63, here via the wall 62. The retaining wall 61 is then fixed by attaching it to the wall 63, here by fixing it to the wall 62 already in place, so that the support wall 63 and the retaining wall 61 are fixedly connected to each other. The support wall 63 is then positioned in the compression direction XI relative to the retaining wall 61. The cartridge(s) 1, 1', the end plate 53, and the stack 51 are then arranged between the retaining wall 61 and the support wall 63, in that order, along the compression direction XL.

[0123] Alternatively, before the application of the force F70, it may occur that the stack 51, in an uncompressed state, does not oppose the placement of the wall 61. In this case, the wall 61 can be fixed either before the application of the force F70, or after the application of the force F70, while the force F70 is maintained, as explained above. In any event, the fixing of the wall 61 is carried out while the end plate 53 is bearing on the stack 51, and the cartridges 1,1' are in prestressed configuration and are assembled with the terminal plate 53 via their assembly means 17.

[0124] Regardless of the solution adopted, once the retaining wall 61 is fixed, the proximal end 11 of the cartridge 1 in the prestressed configuration is distant from the retaining wall 61, along the direction XI, as long as the force F70 is maintained. Indeed, the force F70 compresses the stack 51, so that its size is reduced in the direction XI.

[0125] Once the retaining wall 61 is fixed, the base 10 of the cartridge 1 is placed against the retaining wall 61 in the opposite direction to the XI direction, while the foot 20 remains assembled with the plate 53 via the assembly means 17 and the cartridge 1 remains in prestressed configuration.

[0126] Preferably, this step is carried out before the release of the force F70 and when the cartridge 1 is in the released configuration, by acting on the assembly means 17, by moving the cartridge 1 relative to the plate 53 in the opposite direction to the XI direction. This movement of the cartridge 1 is carried out until the base 10 comes to rest against the retaining wall 61 in the opposite direction to the XI direction.

[0127] Preferably, for this purpose, the external thread 17 is unscrewed within the thread 65, which has the effect of displacing the foot 20, and therefore the cartridge 1 as a whole, relative to the plate 53, in the opposite direction to XI. The unscrewing is carried out by rotating the cartridge 1 through the access port 64, via the actuating head 16. The unscrewing is carried out until the cartridge 1 is brought abutted against the retaining wall 61, the external thread 17 remaining engaged in the thread 65, so that the foot 20 remains assembled with the end plate 53. Then, the cartridge 1 is retained by the wall 61 in the opposite direction to XL

[0128] Once the retaining wall 61 is fixed and the cartridge 1 is retained by the retaining wall 61, the compression force F70 is released and each cartridge 1 is put into the released configuration, which leads to the spring 30 of each cartridge 1, bearing on the base 10 of said cartridge 1 retained by the wall 61, applying the pressing force F30 on the stack 51 in the direction XI, via the foot 20 and the end plate 53, here via the assembly means 17.

[0129] Preferably, the compression force F70 is released first and the cartridge 1 is put into the released configuration once the force F70 has been totally released, or partially released.

[0130] In practice, to release the force F70, the legs 71 of the press 70 are retracted in the opposite direction to the direction XI, until they are completely extracted from the pile 50.

[0131] To then put the cartridge 1 in the released configuration, the screw 43 is advantageously unscrewed via the opening 64 to free the translation of the foot 20 by with respect to the base 10. The screw 43 is preferentially extracted from the stack 50 via the opening 64. The fact that the force F70 has been released and that the cartridge 1 is interposed between the wall 61 and the stack 51 facilitates the unscrewing of the screw 43, on which less axial force is applied. Then, since the retaining system 40 no longer bears the force F30, the spring 30 applies the force F30 to the stack 51 via the foot 20 assembled with the plate 53, bearing against the retaining wall 61 via the base 10. With the cartridge 1 in its released configuration, the force F30 it generates takes over from the force F70, which has already been released, preferably completely released, otherwise partially released. If several cartridges are planned, their F30 forces are added together and collectively take over from the F70 force. This leads to the situation shown in [Fig.2].Therefore, for cartridge 1, or for each cartridge 1 and 1', the force F30, as calibrated when the cartridge was put into the prestressed configuration, is applied to the stack 51 with the same value, or a very close value. Thanks to this method, the desired compressive force value for the stack 51 was applied in a particularly easy, reliable, precise, and safe manner.

[0132] Alternatively, contrary to the above, one or more of the cartridges 1, or all of the cartridges 1, could be placed in the released configuration before releasing the compression force F70. With each cartridge 1 in the released configuration and the force F70 released, each force F30 is applied to the stack 51, as explained above.

[0133] Preferably, once the initial compression force F70 has been released and each cartridge 1,1' has been placed in its free configuration, the component 49 is mounted in each cartridge 1,1' to compensate for axial play and, preferably, to prevent the rotation of the foot 20 relative to the end plate 53 around the central axis X10. In practice, the component 49 is inserted into the relevant cartridge 1 via the orifice 64 and engaged with the threaded hole 42 by screwing it in until the component 49 is fully tightened in the direction XI against the end plate 53. The component 49 is left in this position inside the stack 50 during the use of the stack 50.

[0134] Once the above steps have been completed, the orifices 64 and 67 are advantageously sealed with plugs.

[0135] Any feature described above for one embodiment or variant applies to the other embodiments and variants described above, as far as technically possible.

Claims

1. Demands Cartridge (1), for maintaining in compression, along a compression direction (XI), a stack (51) of electrochemical cells (52) belonging to a fuel cell (50), the cartridge (1) comprising: • a base (10), through which the cartridge (1) is configured to be retained in the opposite direction to the compression direction (XI), by a retaining wall (61) integral with, or belonging to, the fuel cell (50); • a foot (20), which is disposed in the compression direction (XI) relative to the base (10), being slidable relative to the base (10) parallel to the compression direction (XI); • a spring (30), which bears on the base (10) to apply a pressing force (F30) on the foot (20) along the direction of compression (XI); • an assembly means (17) for assembling the foot (20) to an end plate (53) of the fuel cell (50), the foot (20) being configured to bear the end plate (53) against the stack (51) along the compression direction (XI) to maintain the stack (51) in compression, when the foot (20) is assembled with the end plate (53) by the assembly means (17) and the base (10) is retained in the opposite direction to the compression direction (XI) by the retaining wall (61); and • a retaining system (40), which includes a primary retaining portion (41), integral with the base (10), and a secondary retaining portion (42), integral with the foot (20), the primary retaining portion (41) and the secondary retaining portion (42) being configured to: • be coupled to each other when the cartridge (1) is in a pre-stressed configuration, the primary retaining portion (41) and the secondary retaining portion (42) thus coupled preventing the sliding of the foot (20) relative to the base (10) along the compression direction (XI); and • be decoupled from each other when the cartridge (1) is in a released configuration, the primary retaining portion (41) and the secondary retaining portion (42) thus decoupled allowing the foot (20) to slide relative to the base (10) along the compression direction (XI).

2. Cartridge (1) according to claim 1, wherein the assembly means (17) comprises an external thread coaxial with a central axis (X10) of the cartridge (1), the central axis (X10) being parallel to the direction (XI), the external thread being arranged around the foot (20) and the secondary retaining portion (42) and being configured to be engaged with an internal thread (65) belonging to the end plate (53), to assemble the foot (20) with the end plate (53).

3. Cartridge (1) according to claim 2, wherein: • the foot (20) comprises a tubular ring (29), coaxial with the central axis (X10); • the base (10) is received inside the tubular ring (29), thus guiding the sliding of the foot (20) relative to the base (10) parallel to the compression direction (XI); and • the external thread (17) is formed on the tubular ring (29).

4. Cartridge (1) according to any one of claims 2 or 3, wherein the cartridge (1) further comprises an anti-rotation member (49), which is configured to be mounted to prevent rotation of the foot (20) relative to the end plate (53) around the central axis (X10) when the external thread (17) is engaged in the internal thread (65) of the end plate (53) and the retaining system (40) is in the released configuration.

5. Cartridge (1) according to claim 4, wherein: • the retaining system (40) comprises a retaining member (43), through which the primary retaining portion (41) and the secondary retaining portion (42) are coupled, when the cartridge (1) is in pre-stressed configuration; • the retaining member (43) comprises a first threaded body (45); • the secondary retaining portion (42) is formed by a tapped hole, arranged in a through shaft (21) parallel to the compression direction (XI), the primary retaining portion (41) and the secondary retaining portion (42) being coupled to each other when the first threaded body (45) is engaged with the tapped hole and being decoupled from each other when the first threaded body (45) of the retaining member (43) is not engaged with the tapped hole;and • the anti-rotation member (49) includes a second threaded body (48), which is configured to be engaged with the tapping when the first threaded body (45) is not engaged with the tapping, in order to prevent the rotation of the foot (20) relative to the end plate (53) around the central axis (X10) by bearing the anti-rotation member (49) against the end plate (53) along the compression direction (XI).

6. Cartridge (1) according to any one of the preceding claims, wherein the retaining system (40) is configured to allow adjustment of a retaining position of the foot (20), defined with respect to the base (10) and for which the retaining system (40) prevents the foot (20) from sliding, among a continuous range of positions of the foot (20) along the compression direction (XI), in order to adjust the value of the pressing force (F30) applied by the spring (30).

7. Cartridge (1) according to any one of the preceding claims, wherein the spring (30) is a compression spring interposed between the base (10) and the foot (20) along the compression direction (XI).

8. Dimensional compensation system comprising: • the cartridge (1) according to any one of the preceding claims; and • the end plate (53).

9. Dimensional compensation system according to claim 8, further comprising the retaining wall (61) and wherein the retaining wall (61) includes an access port (64), which is through and which is configured to allow the cartridge (1) to be put into the released configuration through the access port (64), when the base (10) is retained by the retaining wall (61), making the retaining system (40) accessible through the access port (64) when the base (10) is retained by the retaining wall (61).

10. Dimensional compensation system according to any one of claims 8 or 9, wherein: • the dimensional compensation system comprises at least one other cartridge (1') according to any one of claims 1 to 7; and • the foot (20) of said at least one other cartridge (1') is configured to be assembled with the end plate (53) via the assembly means (17) of said at least one other cartridge (1'), while the foot of the cartridge (1) is also assembled with the end plate (53) via the assembly means (17) of the cartridge (1').

11. Fuel cell (50) comprising: • the dimensional compensation system according to any one of claims 8 to 10, wherein: • the cartridge (1) is in the released configuration, • the foot (20) is assembled with the end plate (53) by means of the assembly means (17), and • the base (10) is retained in the opposite direction to the compression direction (XI) by the retaining wall (61); • a support wall (63), the support wall (63) and the retaining wall (61) being fixedly attached to each other, the support wall (63) being disposed in the compression direction (XI) relative to the retaining wall (61); and • the stack (51) of electrochemical cells (52), which is arranged between the retaining wall (61) and the support wall (63) and is supported against the support wall (63) following the compression direction (XI), the end plate (53) being in contact with the stack (51) along the compression direction (XI), the spring (30) of the cartridge (1) applying the pressing force (F30) on the stack (51) by means of the foot (20) assembled with the end plate (53), along the compression direction (XI), bearing on the base (10).

12. Fuel cell (50) according to claim 11, wherein the retaining wall (61) and the support wall (63) belong to a housing (60) of the fuel cell (50), the stack (51) being received inside the housing (60), the housing (60) further comprising a longitudinal wall (62) connecting the retaining wall (61) to the support wall (63).

13. Use of the cartridge (1) according to any one of claims 1 to 7, use including: • an assembly of the foot (20) with the end plate (53) by means of the assembly means (17); • an application of an initial compression force (F70) on the stack (51) using a pressure member (70) separate from the cartridge (1), along the compression direction (XI), while the stack (51) is supported against a support wall (63) along the compression direction (XI), the end plate (53) is supported against the stack (51) along the compression direction (XI), the foot (20) is still assembled with the end plate (53) and the cartridge (1) is in prestressed configuration; • a fixing of the retaining wall (61), such that the support wall (63) and the retaining wall (61) are fixedly attached to each other, that the support wall (63) is disposed in the compression direction (XI) relative to the retaining wall (61) and that the cartridge (1), the end plate (53) and the stack (51) are disposed between the retaining wall (61) and the support wall (63) along the compression direction (XI), the fixing of the retaining wall (61) being carried out while the end plate (53) is still bearing against the stack (51), that the cartridge (1) is still assembled with the end plate (53) and that the cartridge (1) is still in pre-stressed configuration; and • a release of the initial compression force (F70) and a release of the cartridge (1), while the fixing of the retaining wall (61) has been carried out, while the retaining wall (61) retains the base (10) in the opposite direction to the compression direction (XI), the spring (30), bearing on the base (10), then applying the pressing force (F30) on the stack (51) via the foot (20) and the end plate (53), along the compression direction (XI).

14. Use according to claim 13, wherein: • the use further comprises, prior to the assembly of the foot (20) with the end plate (53), a pre-stressed configuration of the cartridge (1) by coupling the primary retaining portion (41) with the secondary retaining portion (42), in order to bring the pressing force (F30) to a value desired for the compression retention of the stack (51); and • the assembly of the foot (20) is carried out while the cartridge (1) is in a pre-stressed configuration.

15. Use according to any one of claims 13 or 14, wherein the cartridge (1) is according to any one of claims 4 or 5, the use further comprising, while the initial compression force (F70) has been released and the cartridge (1) has been put into its free configuration, mounting the anti-rotation member (49) to prevent the rotation of the foot (20) relative to the end plate (53) around the central axis (X10).

16. Use according to any one of claims 13 to 15, wherein the fixing of the retaining wall (61) is carried out after the application of the initial compression force (F70), while the initial compression force (F70) is still being applied.

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