Electrode board for bipolar plate, bipolar plate for fuel cell stack, method for manufacturing fuel cell stack

Abstract

The invention relates to an electrode board, i.e. a cathode board or an anode board, for a bipolar plate (100) of a fuel cell stack, in particular for a fuel cell vehicle, comprising a board alignment device (110 / 120) for aligning said electrode board (101 / 102) with respect to a corresponding second electrode board (102 / 101) during the assembly of two electrode boards (102 / 101) to the bipolar plate (100), by means of a board alignment device (120 / 110) of said electrode board, The board alignment device (110 / 120) relates to an electrode board that at least partially defines the area (110 / 120) of the bipolar plate positioning device (105; 110, 120) of the bipolar plate (100) for stacking the bipolar plate (100) in the fuel cell stack (10).

Description

[Technical field]

[0001] The present invention relates to an electrode board for a bipolar plate and to a bipolar plate for a fuel cell stack. Furthermore, the present invention relates to a method for assembling a bipolar plate and a method for stacking bipolar plates. [Background technology]

[0002] In low-temperature polymer electrolyte fuel cells (stationary or mobile) in a fuel cell assembly, for example in a fuel cell system, for example in a fuel cell vehicle, the electrochemical conversion of two reactants of two working media into electrical energy and heat takes place. In this case, the fuel cell comprises at least one membrane electrode assembly (MEA). A fuel cell is usually formed by several membrane electrode assemblies arranged in a stack with bipolar plates arranged between them (fuel cell stack or stack).

[0003] Space on both sides of the large area of ​​the bipolar plates for the fuel cell stack is limited and therefore "precious". Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is therefore to provide a bipolar plate which allows good utilization of the electrically active surfaces on the cathode and / or anode side and / or the port surfaces for the operating medium and / or coolant, so as to provide a high-performance bipolar plate and thus a high-performance fuel cell stack. [Means for solving the problem]

[0005] The object of the present invention is achieved by an electrode board, i.e. a cathode board and / or an anode board, for a bipolar plate and by a bipolar plate for a fuel cell stack of a fuel cell, in particular for a fuel cell vehicle.Furthermore, the object of the present invention is achieved by a method for assembling a bipolar plate and by a method for stacking bipolar plates in a fuel cell stack, in particular for a fuel cell for a fuel cell vehicle.

[0006] Advantageous developments, further features and / or advantages of the invention emerge from the dependent claims and the following description.

[0007] The electrode board according to the present invention comprises a board alignment device for aligning an electrode board with respect to a corresponding second electrode board by means of the board alignment device of the electrode board in order to assemble two electrode boards into a bipolar plate, the board alignment device at least partially forming the area of ​​the bipolar plate positioning device of the bipolar plate for stacking the bipolar plate in a fuel cell stack (temporally after the two electrode boards have been assembled into the bipolar plate).

[0008] That is, the board alignment features, e.g., two through-voids, of one electrode board (cathode board or anode board of the bipolar plate to be prepared) and the board alignment features, e.g., two corresponding through-voids, of a second electrode board (anode board or cathode board of the bipolar plate to be prepared) together form a bipolar plate positioning device when assembled to the bipolar plate, which is then used to position the bipolar plate when stacked with other bipolar plates in a fuel cell stack.

[0009] The contour of the board alignment device can be set on the electrode board in such a way that it can be substantially matched only pointwise (area-wise) or section-wise with the contour of the board alignment device of a second electrode board for the same bipolar plate. That is to say (see also Figs. 3-5), for the assembly of the bipolar plate, the two electrode boards (cathode board and anode board) of the bipolar plate can only be superimposed in such a way that the contours of the mutually associated through-voids (alignment holes, alignment slots (see below)) of the two board alignment devices can be matched only point-wise or section-wise. In this case, for example, the mutually associated through-voids of the two electrode boards are naturally arranged substantially concentrically superimposed on one another, at least section-wise.

[0010] The electrode board cannot include at least a partial bipolar plate positioning device for a bipolar plate that is functionally substantially or completely separated from the board alignment device of this electrode board, i.e. the board alignment device and the partial bipolar plate positioning device (i.e. the area where the associated electrode board for the bipolar plate positioning device of the subsequent bipolar plate is available) are at least partially or completely (in the latter case they are identical) integrated with each other. Naturally, additional positioning aids, such as for example positioning grooves, can be provided on the respective electrode board, which are essentially only used to align two mutually associated electrode boards with each other when assembling the bipolar plate.

[0011] The board alignment device can be arranged in the electrode board, substantially completely in the electrode board or only in the electrode board, i.e. the board alignment device is not arranged by a periphery, in particular by a peripheral edge of the electrode board, in particular also by sections. The board alignment device can comprise at least one cavity, in particular at least one through-void, in the electrode board. The board alignment device can comprise, on the one hand, an alignment hole and, on the other hand, an alignment slot in the electrode board. The alignment hole and the alignment slot can be arranged at the opposite longitudinal ends of the electrode board, spaced apart from each other. In that case, the alignment hole and the alignment slot are preferably arranged at the opposite longitudinal ends of the electrode board, spaced apart from each other linearly or diagonally.

[0012] A bipolar plate according to the invention comprises a cathode board and an anode board fixedly connected to the cathode board, and the board alignment device of the cathode board and the board alignment device of the anode board, which align the cathode board and the anode board with respect to each other in the bipolar plate, together at least partially jointly (by or between them) form a bipolar plate positioning device for stacking the bipolar plate in a fuel cell stack, i.e. the board alignment devices of both the cathode board and the anode board together at least partially form the bipolar plate positioning device of the bipolar plate for stacking the bipolar plate in a fuel cell stack.

[0013] In this case, the combination of the board alignment devices of the cathode board and the anode board (in their entirety) at least partially forms the bipolar plate positioning device of the bipolar plate. Moreover, neither the cathode board nor the anode board can have a board alignment device solely for the mutual alignment of the cathode board and the anode board on the bipolar plate. Moreover, the bipolar plate cannot have board alignment devices separate from its bipolar plate positioning device, in particular for each section on its cathode board and each section on its anode board. Here, possible additional alignment aids are an exception (see above).

[0014] The cathode board and the anode board are fixed one above the other to form a bipolar plate. In this case, the relative contours of the board alignment devices of the cathode board and the anode board can be set so that the contour of the first board alignment device is substantially matched to the contour of the second board alignment device merely pointwise (region by region) or section by section. Furthermore, in a top view of the bipolar plate, the contour of the first board alignment device can be inscribed in the contour of the second board alignment device or circumscribed around the contour.

[0015] This applies in particular to the alignment holes of the board alignment devices (see below and above) or the alignment double holes (overlapping alignment holes) of the bipolar plate positioning devices, respectively. In this case, for example, the circular contour of the n-gon (curved part) of one electrode board can be inscribed in the circular contour of the second electrode board (naturally only in a top view, see alignment holes, respectively, left in Figs. 3 to 5). Preferably, the contour of the board alignment device of the cathode board (electrode board) is at least piecewise "inscribed" in the contour of the board alignment device of the anode board (other electrode board) or the contour of the board alignment device of the anode board (electrode board) is at least piecewise "circumscribed" around the contour of the board alignment device of the cathode board (other electrode board).

[0016] In a top view of the bipolar plate, the surface of the first board alignment device can be set on the bipolar plate in such a way that this surface is simply matched section-wise with the surface of the second board alignment device. This applies in particular to the alignment slots of the board alignment device (see below and also above) or to the alignment double slots (overlapping alignment slots) of the bipolar plate alignment device, respectively. In this case, for example, the (section-wise or sector-shaped) partial surface of the board alignment device of the cathode board (electrode board) can be matched with the (section-wise or sector-shaped) partial surface of the board alignment device of the anode board (the other electrode board) (naturally only in a top view, see the alignment slots on the right in Figs. 3 to 5, respectively).

[0017] The board alignment device of the cathode board and the anode board can form two plate stack through-voids in the bipolar plate for stacking the bipolar plate in the fuel cell stack. That is, the two plate stack through-voids at least partially constitute the bipolar plate positioning device. Both the board alignment device of the cathode board and the board alignment device of the anode board can include two through-voids each, and these four through-voids form two through-voids in the bipolar plate as the bipolar plate positioning device. The two through-voids are formed as alignment holes and alignment slots, respectively, in both the cathode board and the anode board, which form alignment double holes and alignment double slots, respectively, in the bipolar plate as the bipolar plate positioning device.

[0018] The alignment holes of one board alignment device can have only a circular contour and the alignment holes of the other board alignment device can have a circular contour with a curvature, the curvature of the circular contour being preferably located in the corner region of a regular polygon. The alignment holes with only a circular contour are preferably provided in the anode board and the alignment holes with a circular contour with a curvature are preferably provided in the cathode board, although of course this can also be done vice versa.

[0019] The alignment slots of one board alignment device can be formed as slots and the alignment slots of the other board alignment device can be formed as tapered or stepped slots. The alignment slots as slots are preferably located in the anode board and the alignment slots as tapered or stepped slots are preferably located in the cathode board, but of course this can be done vice versa. An alignment hole with a circular contour including a curvature can be inscribed in an alignment hole with only a circular contour, and an alignment slot as tapered or stepped slot can be at least partially inscribed in an alignment slot as a slot (again, of course, in top view).

[0020] In the method according to the invention for assembling bipolar plates for a fuel cell stack, in an alignment step of the method, the cathode board and the anode board of the bipolar plate to be produced are aligned with each other and are fixed to each other in a mounting step of the method which follows in time, in which the cathode board and the anode board are aligned with each other by a board alignment device of the cathode board and the anode board, which board alignment device at least partially forms in the produced and produced bipolar plate a bipolar plate positioning device for stacking the bipolar plates in the fuel cell stack. In the method for assembling bipolar plates, each preferably single cathode board and preferably single anode board are bonded to an associated bipolar plate.

[0021] The board alignment devices of the cathode board and the anode board preferably each comprise two through-holes. In the alignment step, the mutually associated through-holes of the cathode board and the anode board can be arranged substantially concentrically with one another, at least section by section. Furthermore, in the alignment step, the two mutually associated through-holes of the cathode board and the anode board can be centered with one another in the mid-plane (or in a plane parallel to this mid-plane) by the contoured alignment means of the board alignment means. In that case, the contoured alignment means for passing through the through-holes are preferably formed as assembly pins. In their centering region, the alignment means can have a preferably straight section with a polygonal, particularly preferably regular triangular, rectangular or pentagonal cross-section.

[0022] Furthermore, in the alignment step, two mutually related through-voids for the contoured alignment means can be formed as alignment holes with only a circular contour and as alignment holes with a circular contour including a curved portion. In this case, the alignment hole with the circular contour including a curved portion is inscribed in the alignment hole with only a circular contour in a top view. When centering, the contoured alignment means, on the one hand, sits with its outer corner or outer edge inside the cathode board / anode board at the curved portion of the circular contour including the curved portion, and the contoured alignment means, on the other hand, sits with this outer corner or outer edge inside the circular contour of the anode board / cathode board (see FIG. 4, left).

[0023] Furthermore, the two mutually associated through-voids of the cathode board and the anode board can be aligned, i.e. braked, with respect to one another in one or exactly one translational or rotational degree of freedom in one / above mentioned intermediate plane (other degrees of freedom can be realized conditionally) by means of the alignment means of one / above mentioned board alignment means, in which case the preferably cylindrical or conical segment-shaped alignment means for passing through the through-voids is preferably formed as an assembly pin.

[0024] Furthermore, the two mutually associated through-voids for the alignment means can be formed as alignment slots as slots and as tapered or stepped slots. In this case, in top view, the alignment slots are at least partially inscribed in the alignment slots as slots as tapered or stepped slots. When aligned with each other, the preferably cylindrical or conical segment-shaped alignment means, with its outer periphery, on the one hand, sits inside the slots in the cathode board / anode board, and on the other hand, the preferably cylindrical or conical segment-shaped alignment means, with its outer periphery, sits inside the tapered or stepped (preferably larger diameter) slots in the anode board / cathode board (see FIG. 4, right). In this case, in the mutually associated areas, the slots and the tapered or stepped slots have substantially the same diameter.

[0025] After the alignment step, the cathode board and the anode board can be fixed to each other, in particular welded to each other, in a mounting step of the assembly method. The cathode board and / or the anode board can be formed as an electrode board according to the invention. Furthermore, after the mounting step of the assembly method, a bipolar plate can be formed according to the invention.

[0026] In the method according to the present invention for stacking bipolar plates in a fuel cell stack (stacking, stack construction), a bipolar plate stacking means is used to stack multiple bipolar plates with interposed membrane electrode assemblies one above the other in the fuel cell stack, and the bipolar plates are stacked in the fuel cell stack by a bipolar plate positioning device in the bipolar plate, which is at least partially constituted by a board alignment device for the electrode boards of the bipolar plate, in which the electrode boards are aligned with each other to assemble the electrode boards into the bipolar plate.

[0027] The bipolar plate positioning device may include two plate stack through-cavities. In this case, a single plate stack through-cavity may be formed by a double through-cavity of the board alignment device of the electrode board. Furthermore, the single through-cavity of the two mutually associated through-cavities of the electrode board may be centered or positioned by the stacking means of the bipolar plate stacking means, the bipolar plate being positioned in the fuel cell stack. For this purpose, the stacking means preferably has a cylindrical portion for passing through the associated plate stack through-cavity.

[0028] Furthermore, each plate stack through-void can be formed from a registration double hole and a registration double slot of the board registration device of the electrode board of the bipolar plate. Furthermore, in effect, a single registration hole of the registration double hole can be centered by the stacking means of the bipolar plate stacking means, this registration hole having a circular contour, preferably including a curved portion (see FIG. 5, left). Furthermore, in effect, a single registration slot can be centered or positioned by the stacking means of the bipolar plate stacking means, this registration slot being preferably formed as a tapered or stepped slot (see FIG. 5, right). In this case, preferably the tapered or narrower portion of the slot is centered or positioned by the stacking means.

[0029] When stacking bipolar plates, bipolar plates provided with membrane electrode assemblies can be stacked or bipolar plates and membrane electrode assemblies can be stacked alternately. When stacking bipolar plates in a fuel cell stack, the positioning of the bipolar plates can be achieved by only one electrode board of the bipolar plate. In that case, it is preferred that the electrode board is made thicker than the other electrode board of the same bipolar plate. In most cases, this is the cathode plate. The bipolar plates can be formed as bipolar plates according to the invention. Furthermore, the bipolar plates can be assembled by the method according to the invention.

[0030] It is specifically mentioned that the features mentioned within the scope of the method, and in particular the device features mentioned therein (electrode board (cathode board), anode board), bipolar plate), can be applied to the claimed device. Furthermore, the features mentioned within the scope of the device, and in particular the method features mentioned therein (assembly method, stacking method), can be applied to the claimed method. This also applies to the following description of the invention.

[0031] In the following, the invention will be explained in detail on the basis of examples with reference to the attached schematic and not to scale drawings. In the present invention, features can be constructed positively, i.e., present, or negatively, i.e., absent. In this specification, a negative feature is not explicitly described as a feature if its absence is not important to the invention. That is, an invention that has actually been made and has not been constructed by the prior art omits this feature. The absence of a feature in the examples (negative feature) indicates that the feature is optional. The figures in the drawings are merely illustrative. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a simplified block circuit diagram of one embodiment of a fuel cell assembly for a fuel cell system of a fuel cell vehicle. [Diagram 2] FIG. 2 is a top view of a bipolar plate formed from a cathode board and an anode board according to the prior art for a fuel cell stack. [Diagram 3] FIG. 2 is a diagram of a bipolar plate positioning device according to the present invention formed from board alignment devices of the cathode board and the anode board of the bipolar plate, with other contours of the bipolar plate omitted. [Figure 4] A diagram showing the function of the board alignment device of the cathode board (reference numbers are underlined with solid lines, also in Figures 3 and 5) and the anode board (reference numbers are underlined with dashed lines, also in Figures 3 and 5) when assembled into a bipolar plate. [Diagram 5] FIG. 13 illustrates the function of a bipolar plate positioning device, at least partially composed of board alignment devices for the cathode and anode boards, when stacking bipolar plates in a fuel cell stack. [Figure 6] 1 is a simplified flow chart of a method for assembling a bipolar plate. [Figure 7] 4 is a simplified flow chart of a method for stacking bipolar plates into a fuel cell stack. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The present invention is described in detail on the basis of an electrode board 101 / 102, i.e. "semi" bipolar plate 100, i.e. cathode board 101 or anode board 102, and a bipolar plate 100 (see Figures 3 to 5), for a low-temperature polymer electrolyte fuel cell system in a fuel cell vehicle, i.e. a motor vehicle having a fuel cell or fuel cell system, and on the basis of a method 1000 for assembling the bipolar plate 100 (see Figure 6) and a method 2000 for stacking the bipolar plate 100 into a fuel cell stack 10 (see Figure 7).

[0034] In the drawings, only those parts of the fuel cell system necessary for the understanding of the invention are shown. The invention is described in detail and illustrated by means of preferred embodiments, but the invention is not limited to the disclosed embodiments. Further variants can be derived without departing from the scope of protection of the invention.

[0035] 1 shows a fuel cell assembly 1 according to a preferred embodiment with at least one, in particular a plurality, of electrochemical individual fuel cells 11, 11, ... (single cells 11, 11, ...) assembled into a fuel cell stack 10, the individual fuel cells being preferably housed in a fluid-tight stack housing 16. Each single cell 11 comprises an electrode chamber 12, preferably formed as an anode chamber 12 comprising a gas diffusion layer (possibly including a microporous particle layer) and an electrode chamber 13, preferably formed as a cathode chamber 13 comprising a gas diffusion layer (possibly including a microporous particle layer), which are spatially and electrically separated from each other by a membrane of a membrane electrode assembly 15. In this case, the gas diffusion layer preferably belongs to the membrane electrode assembly 15.

[0036] Between two directly adjacent membrane electrode assemblies 15, 15 with their associated anode chamber 12 and cathode chamber 13, there is arranged one bipolar plate 100 (separator plate assembly 100), preferably consisting of an anode board 102 (electrode board 102, monopolar plate 102) and a cathode board 101 (electrode board 101, monopolar plate 101), which serves inter alia to introduce / discharge the working medium 3, 5 to / from the anode chamber 12 of a first individual cell 11 and the cathode chamber 13 of a second individual cell 11 immediately adjacent to this anode chamber, and further to realize the electrically conductive connection between these individual cells 11, 11.

[0037] To supply the fuel cell stack 10 with its own working medium 3 (anode working medium, original fuel), 5 (cathode working medium, usually air), the fuel cell assembly 1 has an anode supply 20 and a cathode supply 30. The anode supply 20 comprises, inter alia, a fuel reservoir 23 for the anode working medium 3 (incoming), an anode supply 21 including a shutoff / metering valve 27 and an ejector 24, an anode exhaust 22 for the anode exhaust medium 4 (outgoing, usually to the ambient environment 2), a fuel recirculation line 25 preferably provided with a fluid conveying device 26 and possibly a water separator.

[0038] The cathode supply section 30 comprises in particular a cathode supply path 31 for the cathode operating medium 5 (incoming, usually from the ambient environment 2), preferably including a fluid transport device 33, a cathode exhaust path 32 for the cathode exhaust medium 6 (outgoing, usually to the ambient environment 2), preferably including a turbine 34, in particular for the fluid transport device 33, which is possibly the turbine of an exhaust turbocharger, preferably a humidifier 36, possibly a wastegate 35 between the cathode supply path 31 and the cathode exhaust path 22, and possibly a water separator.

[0039] The fuel cell assembly 1 further comprises, in particular, a coolant supply 40, through which the fuel cell can be coupled to a cooling circuit, preferably by its bipolar plates 100 (coolant channels 43), for heat transfer for temperature regulation. The coolant supply 40 comprises a coolant inlet channel 41 and a coolant outlet channel 42. The transport of the coolants 7 (incoming), 8 (leaving) circulating in the coolant supply 40 is preferably performed by at least one coolant transport device 44. Besides the fuel cell assembly 1, the fuel cell system comprises peripheral system components, such as a control device, which may for example belong to the fuel cell vehicle itself.

[0040] PRIOR ART Figure 2 shows a bipolar plate 100 according to the prior art, which comprises two welded together electrode boards 101, 102, a cathode board 101 and an anode board 102. The bipolar plate 100 has a bipolar plate positioning device 107 (prior art only) and a separate board alignment device 106 (prior art only) alongside the flow fields for the media and the ports of the channels 21, 22, 31, 32, 41, 42.

[0041] In this case, the associated (double) through-cavities of the bipolar plate positioning device 107 and the board alignment device 106 are set in the bipolar plate 100 side-by-side at the respective longitudinal ends of the bipolar plate 100 (i.e., upper right and lower left in FIG. 2) via webs, i.e. "depressions" of the bipolar plate 100. That is, in order to align the electrode boards 101, 102 with respect to the bipolar plate 100 and to stack the bipolar plate 100 in the fuel cell stack 10, a relatively large amount of space is required in the bipolar plate 100 that cannot be used for the subsequent function of the bipolar plate 100 (dead area or dead space).

[0042] In a prior art method of assembling such a bipolar plate, the cathode board 101 and the anode board 102 are aligned with each other using a board alignment device (106) on the cathode board 101 and a board alignment device (106) on the anode board 102. When the cathode board 101 and the anode board 102 are aligned using the board alignment device 106, they are welded together.

[0043] In a subsequent method of stacking the so assembled bipolar plates 100 into a fuel cell stack 100, the layers 100, 15 of the fuel cell stack 10, i.e. alternating bipolar plates 100 and membrane electrode assemblies 15, are positioned using the bipolar plate positioning device 107 on the bipolar plates 100 and membrane electrode assemblies 15. For this assembly and stacking method, a total of eight through-voids in the two electrode boards 101, 102 or four (double) through-voids in one bipolar plate 100 are required.

[0044] Within the scope of the present invention (see below), in figures 3 to 5, reference signs are underlined with a solid line if they belong to a cathode board 101 of a bipolar plate 100, and underlined with a dashed line if they belong to an anode board 102 of the same bipolar plate 100. Naturally, the reverse is also possible.

[0045] When stacking the fuel cell stack 10 by means of the bipolar plate positioning device, for example the so-called stack hole and stack slot principle is used, see also FIG. 3. Thus, the bipolar plates 100 and the membrane electrode assemblies 15 can be stacked very precisely one on top of the other in layers to form the fuel cell stack 10. Only one side of the bipolar plate 100, consisting of the cathode board 101 and the anode board 102, is always used for the precise positioning of the bipolar plate 100, so that the best tolerances can be achieved. This is preferably the side of the bipolar plate 100 with the larger layer thickness. Here, this is preferably the cathode board 101, which is currently formed about 0.2 mm thicker than the anode board 102, respectively.

[0046] Thus, the cathode board 101 has a diameter of, for example, 8.0 mm in its stack hole 111, and the anode board 102 has a diameter of, for example, 8.4 mm in its stack hole 121. That is, the diameter of the stack hole 111 of the cathode board 101 is smaller (but not smaller) than the diameter of the stack hole 121 of the anode board 102. If the stack holes 111, 121 of both the cathode board 101 and the anode board 102 have the same diameter, the common (double) through hole 111, 121 in the bipolar plate 100 (see plate positioning stack hole 131 (111, 121) below) will be about 7.8 mm based on positioning and tolerances, or have a shape of approximately oval in top view. The stack pins 301 of the bipolar plate stacking means 300 must be selected correspondingly smaller in order to stack the fuel cell stack 10 (see below).

[0047] If the stack holes 111, 121 are arranged concentrically, the stack hole 111 of the cathode board 101 has a diameter of 8.0 mm, and the stack hole 121 of the anode board 102 has a diameter of 8.4 mm, the stack pin 301 can be aligned only with the cathode board 101 and can have a diameter of approximately 8.0 mm (see also the left side of FIG. 5). The same can be done with the diameter and possibly the length (see board alignment stack slot 132 (112, 122) below) of the stack slots 112, 122 in the cathode board 101 and the anode board 102 (see also the right side of FIG. 5). Thereby, the fuel cell stack 10 can be assembled reliably, with small tolerances, and rationally, either manually or automatically. Of course, sizes different from the stated diameter sizes can be applied.

[0048] However, the cathode board 101 and the anode board 102 must be aligned with each other beforehand, i.e., when the cathode board 101 is assembled with the anode board 102 to form the bipolar plate 100. If the stack holes 111, 121 were simply formed as circular stack holes 111, 121 of different sizes, and the stack slots 112, 122 were, for example, simply formed as straight slots 112, 122 of different sizes, they would not be able to be used to align the cathode board 101 with the anode board 102, since they would not allow the cathode board 101 to be aligned correctly with respect to the anode board 102.

[0049] According to the invention, referring to Figures 3 to 6, in a bipolar plate 100, a board alignment device 110 of an electrode board 101, e.g. a cathode board 101, and a board alignment device 120 of an electrode board 102, e.g. an anode board 102, constitute a bipolar plate positioning device 105 (board-bound (platinengebunden): 110, 120 or board-crossing (platinenuebergreifend): 131, 132 (see below)). That is, the board-bound board alignment device 110 is formed as a region 110 of the bipolar plate positioning device 105, and the board-bound board alignment device 120 is also formed as a region 120 of the bipolar plate positioning device 105.

[0050] In this case, board alignment devices 110, 120 (see FIG. 5) are used in a method 1000 of assembling a bipolar plate 100 to align the electrode boards 101, 102 with each other in an alignment step 1001 of the assembly method 1000. In a chronologically next step 1002 of the method 1000, an attachment step 1002, the electrode boards 101, 102 are secured to each other. Such bipolar plates 100 can then be stacked in a fuel cell stack 10 (method 2000, see below).

[0051] A bipolar plate positioning device 105 formed from the board alignment devices 110, 120 (plate stack through-voids 131, 132, see below) is used to stack the bipolar plates 100 successive in time into the fuel cell stack 10. Such a method 2000 for stacking the bipolar plates 100 into the fuel cell stack 10 is shown in FIG. 7. In this case, bipolar plates 100 (step 2001) are stacked alternately with membrane electrode assemblies 15 (step 2002) or bipolar plates 100 provided with membrane electrode assemblies 15 (step 2010 instead of steps 2001, 2002). When the fuel cell stack 10 has its intended number of layers, the stacking method 2000 ends in step 2020. The fuel cell stack 10 can then be housed, for example, in a stack housing 16.

[0052] The board alignment device 110 includes two through-voids 111, 112 in the electrode board 101, and the board alignment device 120 includes two through-voids 121, 122 in the electrode board 102. In that case, the mutually associated through-voids 111, 121 / 112, 122 are set substantially concentrically in the bipolar plate 100. Here, in the electrode boards 101, 102, the mutually associated through-voids 111, 121 can be formed as alignment holes 111, 121, and the mutually associated through-voids 112, 122 can be formed as alignment slots 112, 122. Naturally, other shapes of the mutually associated through-voids 111, 121 / 112, 122 are also applicable.

[0053] The associated through-cavities 111, 121 / 112, 122 of the board alignment devices 110, 120 respectively form plate stack through-cavities 131, 132 of the bipolar plate positioning device 105. Here, the plate stack through-cavities 131 are formed as cross-board plate positioning stack holes 131, which may also be referred to as substantially concentric alignment double holes 111, 121. Further, here, the plate stack through-cavities 132 are formed as cross-board plate positioning stack slots 132, which may also be referred to as substantially concentric alignment double slots 112, 122.

[0054] The method 1000 for assembling the bipolar plate 100 uses board alignment means 200 for engaging with the board alignment devices 110, 120 of the electrode boards 101, 102 (FIG. 4). In this case, the board alignment means 200 comprises preferably contoured alignment means 201, in particular assembly pins 201, for passing through the through-voids 111, 121. Furthermore, the board alignment means 200 comprises preferably cylindrical or conical segment shaped alignment means 202, in particular assembly pins 201, for passing through the through-voids 112, 122.

[0055] The method 2000 for stacking the fuel cell stack 10 uses a bipolar plate stacking means 300 for engaging the bipolar plate positioning devices 105 (110, 120) of the bipolar plate 100 (FIG. 5). In this case, the bipolar plate stacking means 300 includes a preferably cylindrical stacking means 301, in particular a stack pin 301, for passing through the through-voids 111, 121. Furthermore, the bipolar plate stacking means 300 includes a preferably cylindrical stacking means 302, in particular a stack pin 302, for passing through the through-voids 112, 122.

[0056] Here, the alignment holes 121 (through voids 121) have substantially only a circular contour 121, whereas the alignment holes 111 (through voids 111) have a circular contour 111 including a curved portion. In this case, the circular contour 111 including a curved portion (for aligning the electrode boards 101, 102 and for stacking the bipolar plates 100) is inscribed in the circular contour 121 by the curved portion in particular (FIGS. 3 to 5, left).

[0057] Furthermore, here, the alignment holes 122 (through voids 122) have only a substantially straight slot contour 122, whereas the alignment holes 112 (through voids 112) have a tapered or stepped slot contour 112. In this case, the tapered or stepped slot contour 112 (for aligning the electrode boards 101, 102 and also for stacking the bipolar plates 100) is inscribed in the straight slot contour 122, especially by its wider portion (Figures 3 to 5, right).

[0058] In the alignment step 1001, the contoured assembly pin 201 engages the curved part of the circular contour 111 including the curved part and centers only the circular contour 121 therewith, or vice versa, so that the electrode boards 101, 102 are aligned at their longitudinal ends (FIG. 4, left). Furthermore, in the alignment step 1001, the cylindrical or cone-segment assembly pin 202 engages the straight slot contour 122 and centers the tapered or stepped slot contour 112 therewith, or vice versa, so that the electrode boards 101, 102 are aligned at their longitudinal ends (FIG. 4, right). In this case, the cylindrical or cone-segment assembly pin 202 engages the straight slot contour 122 and the wider part of the tapered or stepped slot contour 112.

[0059] In the case of stacking 2001, 2010, only the circular contour 111 with the curved portion is centered on the cylindrical stacking means 301, or vice versa, so that the bipolar plate 100 is positioned at one end in the longitudinal direction. In that case, only the larger circular contour 121 is centered not directly on the cylindrical stacking means 301, but indirectly through the composite of the electrode boards 101, 102. Furthermore, in the case of stacking 2001, 2010, the cylindrical stacking means 301 engages with the tapered or stepped slot contour 112, or vice versa, so that the bipolar plate 100 is positioned at the other end in the longitudinal direction (FIG. 5 right). In that case, the larger straight slot contour 122 for each section is centered not directly on the cylindrical stacking means 302, but indirectly through the composite of the electrode boards 101, 102.

[0060] In summary, the mutually associated through-voids 111, 121 / 112, 122 (transverse to the board alignment devices 110, 120, respectively) of the electrode boards 101, 102 (electrode boards 101, 102 are not fixed to each other) can in particular be formed such that they are mutually centerable / alignable by alignment means 201 (alignment holes 111, 121, possibly alignment slots 112, 122, alternatively or additionally) and / or mutually aligned in one or exactly one degree of freedom by alignment means 202 (alignment slots 112, 122, possibly alignment holes 111, 121, alternatively or additionally) (see FIG. 4).

[0061] Furthermore, a single plate stack through-cavity 131 (111, 121) / 132 (112, 122) of the bipolar plate 100 (electrode boards 101, 102 are fixed to each other) can be formed in such a way that the bipolar plate 100 can be positioned by only a single through-cavity 111 / 112 of the mutually associated through-cavities 111, 121 / 112, 122 of the plate stack through-cavities 131 (111, 121) / 132 (112, 122) when stacking, using the stacking means 301 / 302 (see FIG. 5). Preferably, two plate stack through-cavities 131 (111, 121) / 132 (112, 122) are formed in such a way. In that case, such a single through-cavity 111, 112 in each case belongs in particular to the board alignment device 110 of a single electrode board 101 of the bipolar plate 100. In that case, preferably the thicker of the two electrode boards 101, (102) is preferred, and in most cases this is the cathode board 101.

[0062] If the mutually related through-voids 111, 121 (alignment holes 111, 121, later plate stack through-voids 131) each have a generally circular shape (see Figs. 3-5, left), they are jointly centered by the preferably contoured alignment means 201 of the board alignment means 200 in the assembly method 1000 (step 1001, see Fig. 4, left). In that case, the contoured alignment means 202 is seated (centered) by its corner or corner area substantially inside the two through-voids 111, 121.

[0063] Furthermore, in the stacking method 2000, the preferably cylindrical stacking means 301 of the bipolar plate stacking means 300 is centered in this created plate positioning through-void 131, or vice versa (step 2001 or step 2010, see FIG. 5, left). However, in this case, only one through-void 111 of the mutually associated through-voids 111, 121 is centered as the plate positioning through-void 131, which is the through-void 111 that is inscribed in the through-void 121 in the top view.

[0064] If the mutually related through-voids 112, 122 (alignment slots 112, 122, later plate stack through-voids 132) each generally have a slot shape (see the right in Figs. 3-5), they are centered or aligned together in the assembly method 1000 according to the invention by means of a preferably cylindrical or conical segment-shaped alignment means 202 of the board alignment means 200 (step 1001, see Fig. 4 right). In this case, the alignment means 202 is set at the first longitudinal end (in Fig. 4 this is the left longitudinal end) of the slot-shaped through-voids 112, 122. The alignment means 202 then sits (centered / aligned) substantially inside the two through-voids 112, 122.

[0065] Further, in the stacking method 2000, the preferably cylindrical stacking means 302 of the bipolar plate stacking means 300 is centered or aligned in the created plate positioning through-cavity 132, or vice versa (step 2001 or step 2010, see FIG. 5 right). However, in this case, only one through-cavity 112 of the mutually associated through-cavities 111, 122 is centered or aligned as the plate positioning through-cavity 132, which is the through-cavity 112 inscribed in the through-cavity 122 in the top view. In this case, the stacking means 302 is set at the second longitudinal end of the slot-shaped through-cavities 112, 122 (in FIG. 4, this is the right longitudinal end). [Explanation of symbols]

[0066] 2. Surrounding environment 3 Operating medium 4 Anode exhaust medium 5 Operating medium 6. Cathode exhaust medium 7. Refrigerants 8. Refrigerants 10. Fuel Cell Stack 11 Single cell, fuel cell 12 Electrode chamber, anode chamber 13 Electrode chamber, cathode chamber 15 Membrane electrode assembly 20 Anode supply section 21 Anode supply line 22 Anode exhaust passage 23 Fuel Reservoir 24 Ejector 25 Fuel Recirculation Line 26 Fluid Conveyor 27 Shutoff / Metering Valve 30 Cathode supply section 31 Cathode supply line 32 Cathode exhaust passage 33 Fluid transport device 34 Turbine 35 Westgate 40 Refrigerant supply section 41 Refrigerant inflow path 42 Refrigerant outlet path 43 Coolant path 44 Refrigerant transport device 100 Bipolar Plates 101 Electrode board, cathode board 102 Electrode board, anode board 105 Bipolar Plate Positioning Device 106 Board Alignment Device 107 Bipolar Plate Positioning Device 110 Board alignment device 111 Circular contour including stack holes, through-voids, and curved portions of cathode board 101 112 Slot, Alignment Double Slot, Through Hole, Alignment Hole, Slot Profile 120 Board alignment device 121 Stack hole, through-void, circular contour of anode board 102 122 slot, alignment double slot, through hole, alignment hole, slot contour 131 Plate positioning stack hole 132 Plate Positioning Stack Slots 200 Board alignment means 201 Alignment means, assembly pin 202 Alignment means, assembly pin 300 Bipolar Plate Stack Means 301 Stack pins, stacking means 302 Stack pins, stacking means 1000 How to assemble 2000 How to stack

Claims

1. An electrode board (101 / 102), i.e. a cathode board (101) or an anode board (102), for a bipolar plate (100) of a fuel cell stack (10), in particular for a fuel cell vehicle, an electrode board including a board alignment device (110 / 120) for aligning the electrode board (101 / 102) with a corresponding second electrode board (102 / 101) by means of a board alignment device (120 / 110) of the electrode board in order to assemble the two electrode boards (102, 101) to the bipolar plate (100); The board alignment device (110 / 120) at least partially forms an area (110 / 120) of a bipolar plate positioning device (105; 110, 120) of the bipolar plate (100) for stacking the bipolar plate (100) in a fuel cell stack (10).

2. 2. The electrode board (101 / 102) according to claim 1, characterized in that the contour of the board alignment device (110 / 120) is set on the electrode board (101 / 102) such that said contour can be substantially matched merely pointwise or piecewise with the contour of the board alignment device (120 / 110) of the second electrode board (102 / 101) for the same bipolar plate.

3. the electrode board (101 / 102) does not include at least a partial bipolar plate positioning device for the bipolar plate (100) that is functionally substantially or completely separated from the board alignment device (105) of the electrode board; the board alignment device (110 / 120) is located within the electrode board (101 / 102), substantially entirely within the electrode board, or only within the electrode board; the board alignment device (110 / 120) comprises at least one cavity (111 / 121, 112 / 122) in the electrode board (101 / 102), in particular at least one through cavity (111 / 121, 112 / 122); and / or An electrode board (101 / 102) according to any one of claims 1 or 2, characterized in that the board alignment device (110 / 120) comprises, on the one hand, alignment holes (111 / 121) and, on the other hand, alignment slots (112 / 122) in the electrode board (101 / 102).

4. A bipolar plate (100) for a fuel cell stack (10) of a fuel cell, in particular for a fuel cell vehicle, comprising a cathode board (101) and an anode board (102) fixedly connected to said cathode board, A bipolar plate, characterized in that a board alignment device (110) for the cathode board (101) and a board alignment device (120) for the anode board (102), which align the cathode board (101) and the anode board (102) with respect to each other in the bipolar plate (100), together at least partially jointly form a bipolar plate positioning device (105) for stacking the bipolar plate (100) in a fuel cell stack (10).

5. the combination of the board alignment devices (110, 120) of the cathode board (101) and the anode board (102) at least partially forms the bipolar plate positioning device (105) of the bipolar plate (100); - neither the cathode board (101) nor the anode board (102) has a board alignment device (106) solely for aligning the cathode board (101) and the anode board (102) with respect to each other on the bipolar plate (100); and / or The bipolar plate (100) of claim 4, characterized in that neither the bipolar plate cathode board (101) nor the bipolar plate anode board (102) has a board alignment device (106) separate from the bipolar plate positioning device (107) of the bipolar plate.

6. The cathode board (101) and the anode board (102) are fixed one above the other to form a bipolar plate (100) as follows: the relative contours of the board alignment devices (110, 120) are set such that the contour of the first board alignment device (110 / 120) is substantially matched only pointwise or piecewise with the contour of the second board alignment device (120 / 120); in a top view of the bipolar plate (100), the contour of the first board alignment device (110 / 120) is inscribed within or circumscribed around the contour of the second board alignment device (120 / 110); and / or - A bipolar plate (100) as described in any one of claims 4 or 5, characterized in that, in a top view of the bipolar plate (100), the surface of the first board alignment device (110 / 120) is set on the bipolar plate (100) so that said surface is simply matched piecewise with the surface of the second board alignment device (120 / 110).

7. the board alignment devices (110, 120) of the cathode board (101) and the anode board (102) form two plate stack through-voids (131, 132) in the bipolar plate (100) for stacking the bipolar plate (100) in the fuel cell stack (10); - both the board alignment device (110) of the cathode board (101) and the board alignment device (120) of the anode board (102) each include two through-holes (111, 112; 121, 122), and the four through-holes (111, 112; 121, 122) form two through-holes (111 / 121, 112 / 122) in the bipolar plate (100) as bipolar plate positioning devices (105); and / or - The bipolar plate (100) according to any one of claims 4 to 6, characterized in that the two through-voids (111, 112; 121, 122) are formed as alignment holes (111, 121) and as alignment slots (112, 122) respectively in both the cathode board (101) and the anode board (102), and the alignment holes and the alignment slots (111, 121; 112, 122) form in the bipolar plate (100) alignment double holes (111, 121) and alignment double slots 112, 122 as bipolar plate positioning devices (105).

8. the alignment holes (121) of the one board alignment device (120) have only a circular contour (121) and the alignment holes (111) of the other board alignment device (110) have a circular contour (111) that includes a curvature; the alignment slots (122) of the one board alignment device (120) are formed as slots (122) and the alignment slots (112) of the other board alignment device (110) are formed as tapered or stepped slots (112); and / or A bipolar plate (100) according to any one of claims 4 to 7, characterized in that the alignment hole (111) having a circular contour (111) including the curvature is inscribed within the alignment hole (121) having only the circular contour (121), and the alignment slot (112) as a tapered or stepped oblong hole (112) is at least partially inscribed within the alignment slot (122) as an oblong hole (122).

9. A method (1000) for assembling a bipolar plate (100) for a fuel cell stack (10) of a fuel cell, in particular for a fuel cell vehicle, comprising: In an alignment step (1001) of the method (1000), the cathode board (101) and the anode board (102) of the bipolar plate (100) to be produced are aligned with each other and are fixed to each other in a mounting step (1002) of the method (1000) which follows in time, The method of claim 1, wherein in the alignment step (1001), the cathode board (101) and the anode board (102) are aligned with each other by board alignment devices (110, 120) for the cathode board (101) and the anode board (102), and the board alignment devices (110, 120) at least partially form in the fabricated (1002) bipolar plate (100) a bipolar plate positioning device (105) for stacking the bipolar plate (100) in a fuel cell stack (10).

10. The board alignment devices (110, 120) of the cathode board (101) and the anode board (102) each include two through-holes (111, 112; 121, 122), and in the alignment step (1001), the mutually associated through-voids (111, 121; 112, 122) of said cathode board (101) and said anode board (102) are arranged at least piecewise substantially concentric with one another; the contoured alignment means (201) of the board alignment means (200) ensures that the two mutually associated through-voids (111, 121) of said cathode board (101) and said anode board (102) are mutually centered in the mid-plane; the two mutually associated through-voids (111, 121) for said contoured alignment means (201) are formed as an alignment hole (121) having only a circular contour (121) and as an alignment hole (111) having a circular contour (111) including a curved portion, by means of the alignment means (202) of one / the board alignment means (200), two mutually associated through-voids (112, 122) of the cathode board (101) and the anode board (102) are aligned with one another in one or exactly one degree of freedom in one / the intermediate plane; and / or - The assembly method (1000) described in claim 9, characterized in that the two mutually associated through-voids (112, 122) for the alignment means (202) are formed as an alignment slot (122) as a long hole (122) and as an alignment slot (112) as a tapered or stepped long hole (112).

11. - temporally subsequent to said alignment step (1001), in a mounting step (1002) of said assembly method (1000), said cathode board (101) and said anode board (102) are fixed to each other, in particular welded to each other; the cathode board (101) and / or the anode board (102) are formed as an electrode board (101, 102) according to any one of claims 1 to 3, and / or - The assembly method (1000) according to any one of claims 9 or 10, characterized in that, after the mounting step (1002) of the assembly method (1000), a bipolar plate (100) is formed according to any one of claims 4 to 8.

12. A method (2000) for stacking bipolar plates (100) in a fuel cell stack (10) for a fuel cell, in particular for a fuel cell vehicle, comprising: A method in which a plurality of bipolar plates (100) having intervening membrane electrode assemblies (15) are stacked one above the other to form a fuel cell stack (10) using a bipolar plate stacking means (300), comprising: Stacking (2001, 2010) a bipolar plate (100) into the fuel cell stack (10) by a bipolar plate positioning device (105) on the bipolar plate (100); The bipolar plate positioning device (105) is at least partially constituted by board alignment devices (110, 120) for the electrode boards (101, 102) of the bipolar plate (100) that align the electrode boards (101, 102) with each other (1000) for assembling the electrode boards to the bipolar plate (100).

13. The bipolar plate positioning device (105) includes two plate stack through-voids (131, 132); a single plate stack through-void (131 / 132) is formed by a double through-void (111,121 / 112,122) in the board alignment device (110,120) of the electrode board (101,102); a single through-void (111 / 121, 112 / 122) of two mutually associated through-voids (111, 121; 112, 122) of said electrode boards (101, 102) is centered or positioned by the stacking means (301, 302) of said bipolar plate stacking means (300) and said bipolar plate (100) is positioned in said fuel cell stack (10); each plate stack through-void (131, 132) is formed from a registration double hole (111, 121) and a registration double slot (112, 122) of the board registration device (110, 120) of the electrode board (101, 102) of the bipolar plate (100); In effect, a single alignment hole (111) of said alignment double holes (111, 121) is centered by the stacking means (301) of said bipolar plate stacking means (300), said alignment hole (111) having a circular contour (111), preferably including a curvature; and / or The stacking method (2000) of claim 12, characterized in that essentially a single alignment slot (112) is centered or positioned by the stacking means (302) of the bipolar plate stacking means (300), the alignment slot (112) being preferably formed as a tapered or stepped slot (112).

14. When stacking the bipolar plates (100) (2001, 2002; 2010), the bipolar plates (100) provided with the membrane electrode assemblies (15) are stacked (2010) or the bipolar plates (100) and the membrane electrode assemblies (15) are stacked alternately (2001, 2002); When stacking (2001, 2010) the bipolar plate (100) in the fuel cell stack (10), the bipolar plate (100) is positioned by a single electrode board (101 / 102) of the bipolar plate (100), and / or The stacking method (2000) according to any one of claims 12 or 13, characterized in that the bipolar plates (100) are formed according to any one of claims 4 to 8 and / or assembled by the method according to any one of claims 9 to 11.

15. In a fuel cell, a fuel cell assembly (1) or a fuel cell system, in particular for a fuel cell vehicle, the fuel cell, the fuel cell assembly (1) or the electrode board (101 / 102) of the fuel cell system is formed according to any one of claims 1 to 3, the fuel cell, the fuel cell assembly (1) or the bipolar plate (100) of the fuel cell system is formed according to any one of claims 4 to 8, the fuel cell, the fuel cell assembly (1) or the bipolar plate (100) of the fuel cell system is assembled by the method (1000) according to any one of claims 9 to 11, and / or A fuel cell, a fuel cell assembly or a fuel cell system, characterized in that the fuel cell, the fuel cell assembly (1) or the fuel cell stack (10) of the fuel cell system is stacked by the method (2000) according to any one of claims 12 to 14.

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