Voltage monitoring device for a cell stack, particularly a fuel cell stack

Abstract

Disclosed is a battery stack (1) comprising a plurality of electrical plates (2;4) sandwiching an insulating layer (8), wherein at least one of the plurality of electrical plates (2;4) has a voltage monitoring element (20) disposed thereon for monitoring a voltage of the electrical plate (2;4), and wherein at least one of the electrical plates (2;4) on which the voltage monitoring element (20) is disposed has at least one through hole (18;19), and wherein the voltage monitoring element (20) is disposed on and / or in the through hole (18;19).

Description

[Technical Field]

[0001] The present invention relates to a cell stack, in particular a fuel cell stack, according to claim 1. [Background technology]

[0002] A cell stack typically consists of multiple stacked electrical plates separated from each other by insulating layers.

[0003] In the particular case of a fuel cell stack, the electrical plates are bipolar plates, and the insulating layers are multilayer membrane electrode assemblies. The bipolar plates themselves are a combination of anode and cathode plates fixed together, separated, or sandwiched, by the membrane electrode assembly. The cathode and anode plates that form the bipolar plates are typically conductive metal or graphite plates, so-called flow field plates, with a reactant flow field on one side and a cooling fluid flow field on the other. In the assembled membrane electrode assembly, the flow field plates are positioned on top of each other, with the cooling fluid flow fields facing each other and the reactant flow fields facing the sandwiching membrane electrode assembly. The current generated by the membrane electrode assembly during fuel cell stack operation results in a potential difference between the bipolar plate assemblies.

[0004] During operation of a cell stack, the voltage produced by the stacked cells must be monitored to determine whether the stack is operating within its intended operating parameters. To that end, each electrical plate typically includes a voltage monitoring element secured to the electrical plate and with wires for connecting the voltage monitoring element to an external voltage monitoring control device that monitors and controls the operation of the stack.

[0005] It is therefore known to use wires as voltage monitoring elements by soldering or welding the wires directly to the electrical plates. In the field of fuel cell stacks, it is also known to use pin connections, in which pins are inserted between the plates of the bipolar plates and they are fixed by friction or press fit.

[0006] However, placing and securing wires within a cell stack is cumbersome and time-consuming, making the stacking process inefficient and slow. Furthermore, known securing methods are also prone to failure as the wires and pins can come loose from the plates or the wires and pins are misplaced, leading to stack failure.

[0007] Furthermore, because the stack of electrical plates and associated insulating layers is typically intimate, there is no space in the cell stack to fit a voltage monitoring element that would be easy to install. Summary of the Invention [Problem to be solved by the invention]

[0008] It is therefore an object of the present invention to provide a voltage monitoring element that can be implemented in a cell stack, particularly a fuel cell stack, in a more efficient and reliable manner. [Means for solving the problem]

[0009] This object is solved by a battery stack according to claim 1.

[0010] The present invention proposes a fuel cell stack comprising a plurality of electrical plates sandwiching an insulating layer, wherein at least one of the electrical plates is provided with a voltage monitoring element for monitoring the voltage of the electrical plate. More specifically, the voltage monitoring and control element may be molded, preferably injection molded.

[0011] In order to mount the voltage monitoring element more efficiently, the at least one electrical plate on which the voltage monitoring element is disposed has at least one through-hole, and the voltage monitoring element is disposed on and / or in the through-hole, thereby providing additional space that allows the voltage monitoring element to be accommodated.

[0012] It should be noted that in general, in this application, the term "electrical plate" does not necessarily refer to a rigid electrical plate. Similarly, an electrical element (anode or cathode), such as a flexible layer, may be termed an electrical plate in this application.

[0013] Furthermore, the cell stack may be a fuel cell stack, in which case the electrical plates are bipolar plates consisting of anode and cathode plates fixed together, and in which case the insulating layer is a multilayer membrane electrode assembly. The bipolar plates are typically rigid metal or graphite plates equipped with flow field structures for supplying and distributing reactants and / or coolants to the bipolar plates and / or the adjacent membrane electrode assemblies.

[0014] According to a preferred embodiment, the voltage monitoring element is made of an electrically insulating material and includes electrical contact elements made of a conductive material, which are arranged on the surface of the voltage monitoring element and configured to contact the electrical plate. Since known pins or wires are extremely small, fastening the voltage monitoring element to the plate is a very delicate operation. Furthermore, there is a high risk of misplacing pins, which can lead to damage to stack elements and ultimately to failure of the entire stack. Providing a voltage monitoring element that is primarily made of an electrically insulating material and includes conductive elements only in specific locations allows for simpler and more streamlined operation and installation of the voltage monitoring element. It should be noted that the electrical contact elements typically include integrated wires for known connection to an external voltage monitoring control device.

[0015] According to a further preferred embodiment, the voltage monitoring and control device has a base plate and a protruding portion that is recessed from the base plate to form a step between the base plate and the protruding portion, thereby providing an easy-to-handle element that can be time-efficiently positioned on the electrical plate and in the through-hole.

[0016] Therefore, the height h of the voltage monitoring element is greater than the thickness D of the electrical plate (2). EP is less than (h <D EP In particular, in the case of the voltage monitoring element having the above-mentioned base plate and protruding portion, the height h of the protruding portion of the voltage monitoring element is preferably p is the thickness D of the electric plate (2) EP is less than (h p <D EP ) This allows for a voltage monitoring element that is flush with the electrical plate on at least one side. Such a voltage monitoring element does not require additional space, as it is at least partially completely contained within the electrical plate.

[0017] According to a further advantageous embodiment, the voltage monitoring elements have, on the opposite side of the protruding portion, a recess in the base plate that is dimensioned to accommodate the protruding portion of an adjacent voltage monitoring element, so that one voltage monitoring element is configured to be stacked on top of another voltage monitoring element, so that even if the voltage monitoring element extends beyond the electrical plate, for example after compression of the stack, the excess does not negatively interfere with the overall dimensions of the stack.

[0018] On the other hand, if such a recess is provided, the height h of the protruding part of the voltage monitoring element p is the thickness D of the electrical plate EP becomes larger than (h p >D EP ) and the depth h of the recessr It would also be possible to provide a voltage monitoring element such that the protruding portion of the voltage monitoring element is configured to receive that portion of the protruding portion of the voltage monitoring element that extends beyond the electrical plate. This would also define a particular orientation of the stacked cell stack components relative to each other, so that the voltage monitoring element could also be used as an alignment feature for the components of the stack.

[0019] According to a further preferred embodiment, the diameter of the base plate is designed to be larger than the diameter of the through-hole, such that the surface of the step at least partially abuts the surface of the electrical plate and the protruding portion extends through the through-hole of the electrical plate, thereby allowing a secure mounting of the voltage monitoring element on and in the through-hole of the electrical plate.

[0020] It is further preferred if the voltage monitoring element further comprises a cover part, the diameter of which is larger than the diameter of the through-hole so that the voltage monitoring element is fixed to the electrical plate, thereby enabling connection and fixing of the cover element to both sides of the plate. The cover element can also be understood as, for example, a snap element that extends beyond the edge of the electrical plate after being inserted through the through-hole so that the voltage monitoring element is fixed to the electrical plate.

[0021] Alternatively or additionally, the cover portion may be a separate element configured to interact with the protruding portion of the voltage monitoring element to secure the voltage monitoring element to the electrical plate. Hereby, it is particularly preferred that the cover element has a recess designed to receive the protruding portion, such that the connection between the cover elements is made by form-fit or pressure-fit. For example, the cover element can be pressed and / or clicked onto the protruding portion.

[0022] To further provide an internal alignment feature, the cover element may further include a protrusion on the side opposite the surface facing the electrical plate, which allows interaction with an adjacent voltage monitoring element, and in particular with the recess of the adjacent voltage monitoring element. Additionally, the cover element may have an annular shape that interacts with the protrusion in a friction fit manner, such that the protrusion extends through the annular cover element and can be received in the recess of the adjacent voltage monitoring element.

[0023] This allows the cover element to ensure that the voltage monitoring element remains secured to the electrical plate even when the electrical plate is not placed in the stack, which also allows for pre-attachment of the voltage monitoring element to the electrical plate prior to stacking.

[0024] According to a further preferred embodiment, the electrical contact elements are arranged on a surface of the voltage monitoring element, preferably on the base plate, preferably on the step and / or on the protruding portion and / or on the cover portion, such that the electrical contact elements contact the electrical plate.

[0025] As mentioned above, the voltage monitoring element may be made of an electrically insulating material, preferably a plastic material, and the electrical contact element may be made of a conductive material. In this regard, metals such as copper, aluminum, silver, gold, and tin are preferred. When determining the specific material of the electrical contact element, the material of the bipolar plate must be taken into consideration to avoid galvanic problems. For stainless steel bipolar plates, a coated copper material, such as gold-plated copper, is preferred. Furthermore, the electrical contact element may be a resilient element, and preferably, the electrical contact element may be resiliently shaped. For example, the electrical contact element may be shaped as a spring.

[0026] As mentioned above, the electrical contact elements are connected to wires for connection to an external voltage monitoring and control device, and the electrical contact elements can also be made from the wires or wire-like materials.

[0027] According to further embodiments, the voltage monitoring element may be made from the same material as the insulating layer or may even be an integral part of the insulating layer. In particular, the voltage monitoring element may be made from a subgasket material of the membrane electrode assembly or may be an integral part of the membrane electrode assembly. This allows for space-saving accommodation of the voltage monitoring control device in the cell stack or the fuel cell stack, respectively.

[0028] According to a further preferred embodiment, the electrical plate further comprises a flow field for distributing reactants on the electrical plate. In that regard, the flow field may be designed as a protruding structure protruding from the base of the plate. Alternatively, the plate may have other protruding structures, such as bead seals, also protruding from the base of the electrical plate. These protruding structures are common in fuel cells, where the bipolar plate is designed to distribute reactants to the membrane electrode assembly.

[0029] If the electrical plate has at least one protruding structure, e.g., a bead seal or a flow field, protruding from the base of the electrical plate in the direction of the adjacent insulating layer, the height h of the base plate of the voltage monitoring element b is the protruding height D of the protruding structure above the base of the electrical plate PS is close to, and preferably less than (h b ≒D PS , preferably h b <D PS ) This allows the voltage monitoring element to be reliably placed within the battery stack without requiring additional space, which further enables the voltage monitoring element to be implemented within the battery stack without increasing the size of the battery stack.

[0030] When the electrical plate has at least one protruding structure, such as a bead seal or a flow field, protruding from the base of the electrical plate in the direction of the adjacent insulating layer, the height h of the cover portion of the voltage monitoring element c Also, the protrusion height D of the protrusion structure on the base of the electrical plate PS is close to, and preferably less than (h c ≒D PS , preferably h c <D PS ) This further allows the voltage monitoring element to be reliably disposed within the battery stack without requiring additional space and without increasing the size of the battery stack.

[0031] According to a further preferred embodiment, the protruding portion of the voltage monitoring element may have a first portion and a second portion, wherein the second portion is recessed relative to the first portion, thereby forming a further step between the first and second portions of the protruding portion, the further step comprising an electrical contact element configured to contact the electrical plate. It is further preferred that both the step between the base plate and the first portion and the step between the first and second portions comprise an electrical contact element. This allows electrical connection of not only a single electrical plate, but also two electrical plates positioned adjacent to each other, further reducing the time required during stacking and simplifying the stacking process by requiring a separate voltage monitoring element for each of three plates.

[0032] Thereby, it is further preferred that the electrical plate has first and second through holes on and / or in which the voltage monitoring elements are accommodated, wherein the first and second through holes have different dimensions and / or shapes from each other, which allows in particular advantageous interaction between the stepped voltage monitoring elements and two adjacent electrical plates.

[0033] It is further advantageous if the dimensions of the first portion of the protruding portion match the dimensions and / or shape of the first through-hole and the dimensions of the second portion of the protruding portion match the dimensions and / or shape of the second through-hole, thereby enabling a fail-safe positioning of the voltage monitoring element and through-hole / electrical plate.

[0034] It is further preferred that adjacent electrical plates and their corresponding first and second through holes are positioned such that the first through hole of one electrical plate is aligned with the second through hole of the adjacent electrical plate. In this regard, it is further preferred that the electrical plates are symmetrical about a 180° rotation about a surface normal of the electrical plate. If the electrical plate is a bipolar plate, it is preferred that the bipolar plate be symmetrical about a 180° rotation about a surface normal of the cathode or anode side. A 180° rotation of each second electrical plate in the stack thereby results in automatic alternating placement of the first and second through holes. In addition to simplifying manufacturing, stacking, and alignment, only one set of electrical plates needs to be produced, which also allows for compensation for manufacturing tolerances that may result in stacks of unequal dimensions.

[0035] According to a further preferred embodiment, the cell stack has at least two, preferably three, stacked electrical plates, in which case the height h of the first and second portions is p1 ,h p2The battery stack is designed so that the electrical contact element located on the first step contacts the first electrical plate and the further step between the first and second portions contacts the second electrical plate. Furthermore, the second portion may protrude into an opening in the second electrical plate but not beyond the second electrical plate. Alternatively, the second portion may extend beyond the second electrical plate and be accommodated in a recess in an adjacent voltage monitoring control device located on a third bipolar plate. This allows the voltage monitoring element to be implemented within the battery stack without increasing the size of the battery stack.

[0036] It will be apparent that the voltage monitoring element may comprise a number of further steps, each step being provided with an electrical connector in contact with a respective electrical plate.

[0037] Further preferred embodiments are defined in the description and drawings as well as in the dependent claims, in which respect an element described or shown in combination with other elements may also be present alone or in combination with other elements without departing from the scope of protection.

[0038] Preferred embodiments of the invention will now be described with reference to the drawings, which are for illustrative purposes only and are not intended to limit the scope of protection, which is defined solely by the appended claims. [Brief explanation of the drawings]

[0039] [Figure 1] 1 is a cross-sectional view of a fuel cell stack according to a first exemplary embodiment. [Figure 2] FIG. 4 is a cross-sectional view of a fuel cell stack according to a second exemplary embodiment. [Figure 3] FIG. 10 is a cross-sectional view of a fuel cell stack according to a third exemplary embodiment. [Figure 4] FIG. 10 is a cross-sectional view of a fuel cell stack according to a fourth exemplary embodiment. [Figure 5]FIG. 10 is a cross-sectional view of a fuel cell stack according to a fifth exemplary embodiment. [Figure 6] FIG. 10 is a cross-sectional view of a fuel cell stack according to a sixth exemplary embodiment. [Figure 7] FIG. 10 is a cross-sectional view of a fuel cell stack according to a seventh exemplary embodiment. [Figure 8] FIG. 13 is a cross-sectional view of a fuel cell stack according to an eighth exemplary embodiment. [Figure 9] FIG. 13 is a cross-sectional view of a fuel cell stack according to a ninth exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0040] In the following, identical or similarly functioning elements are designated with the same reference numerals.

[0041] The principles of the present invention are described below in the context of a fuel cell stack. However, the principles are equally applicable to any other type of cell or cell stack. Furthermore, features illustrated with respect to one embodiment may also be included alone or in combination with other embodiments.

[0042] 1-9 partially illustrate a fuel cell stack 1 having at least one bipolar plate 2 having an anode plate 4 and a cathode plate 6. Each bipolar plate 2 is sandwiched by a first membrane electrode assembly 8-1 and a second membrane electrode assembly 8-2. The membrane electrode assembly 8 itself is typically a multi-layer membrane electrode assembly, but for simplicity, is shown in the figures as just a single layer. The bipolar plate 2 is further illustrated as having protruding structures 10, 14, e.g., bead seals or flow field channel-like structures, that protrude beyond the bases 12 (anode side) and 16 (cathode side) of the bipolar plate 2, where the bases 12 and 16 extend beyond the thickness D of the bipolar plate. EP The protruding structure has a thickness D PS or height h シール The following are specified respectively.

[0043] 1-9 show various preferred embodiments of the voltage monitoring element 20. Each voltage monitoring element has a height h ec 1. For simplicity, the electrical contact elements 22 are shown only diagrammatically in the drawings. It should be noted that each electrical contact element 22 typically includes a wire (not shown) for connection to an external voltage monitoring and control device.

[0044] To attach the voltage monitoring element 20 to the bipolar plate 2, the bipolar plate 2 is provided with a through hole 18 through which the voltage monitoring element 22 can be inserted and passed.

[0045] Furthermore, in the illustrated embodiment, the voltage monitoring element 20 is made of an electrically insulating material, while the electrical contact element 22 is made of a conductive material. The electrically insulating material may be a plastic material, and the voltage monitoring element 20 may be molded or injection molded. The electrical contact element 22 may be made of copper. Furthermore, the electrical contact element 22 may be a resilient element, and preferably, the electrical contact element 22 is resiliently molded. For example, the electrical contact element 22 may be shaped as a spring, which is schematically illustrated in FIGS. 1-9 by the semicircular shaped electrical contact element.

[0046] The voltage monitoring element 20 as shown in FIGS. 1 to 9 has a height h b of base plate 24 and height h p The protruding portion 26 is recessed from the base plate 24 such that a step 28 is formed between the base plate 24 and the protruding portion 28. Furthermore, the electrical contact elements 22 are disposed on the base plate 24, particularly on the step 28, such that the electrical contact elements 22 contact each bipolar plate 2.

[0047] Furthermore, as can be seen from FIG. 1, the height h of the base plate 24 b and the height h of the electrical contact element 22 ecis the total height h of the base plate 24 and the electrical contact element 22 b +h ec is the protruding part 14 of the bipolar plate 2, e.g., the height h of the bead seal シール (=D PS ) is less than (h シール >h b +h c ) is designed to

[0048] Height h of the protruding part of the voltage monitoring element 20 p is that the voltage monitoring element 20 does not protrude through both the anode and cathode plates 4, 6 (h p <D EP ) (see FIG. 1), or the voltage monitoring element 20 may be designed to protrude through both the anode and cathode plates 4, 6 (h p >D EP ) (see FIG. 2). In either case, however, the overall height H of the voltage monitoring element 20 v The total height H of the bipolar plate 2 at any point BPP Does not protrude beyond (H BPP >H V ). In that case, H BPP =D EP +h シール .

[0049] As can be seen in the embodiment shown in FIG. 3, the electrical contact elements 22 can be located in various locations, such as on the sides of the protruding portion 28, rather than on the step 28 as shown.

[0050] Furthermore, as can be seen in FIG. 3 and FIGS. 4 to 8, the voltage monitoring element 20 has a height h c The cover part 30 may have a cover portion 30 having a cover portion 30a, 30b, 30c, 30d, 30e, 30f, 30f, 30g, 30h, 30h, 30g, 30h, 30f ...

[0051] In the embodiment of FIG. 3, the cover part 30 is an integral part of the voltage monitoring element 20 and may be designed as a hook 32 configured to snap onto the edge of the through-hole 18 of the bipolar plate 2 .

[0052] Alternatively, the cover portion 30 may be designed as a separate element that can interact with the protruding portion 26 of the voltage monitoring element 20, as shown in Figures 4 to 6. In that regard, for example, the cover portion 30 as shown in Figure 4 may comprise a connecting portion 34. In the illustrated embodiment, the connecting portion 34 is provided with a depth h provided on the protruding portion 26 of the voltage monitoring element 20 in order to securely fasten the cover portion 30 to the protruding portion 26. r The cover part 30 is designed as a protrusion that can be accommodated in a recess (also not shown) having a recess (not shown). Of course, other connections are possible as well. For example, the cover part 30 may further have a depth h that interacts with the protrusion part 26. r The recess may have a recess having a

[0053] In all cases, the cover portion 30 and the protruding portion 26 preferably interact such that the cover portion 30 and the protruding portion 26 are secured to one another, for example by a press fit, a friction fit, etc. To this end, additional elements, such as snap elements, may be provided on the protruding portion 26 or on the cover portion 30. The cover portion 30 and the protruding portion 26 are joined to one another, for example by gluing or welding, etc.

[0054] If the voltage monitoring element 20 includes a cover portion 30, it is of course possible to arrange electrical contact elements on the cover portion (see, for example, FIG. 5), on both the cover portion 30 and the base portion 24 (see, for example, FIG. 6), or on any other surface of the voltage monitoring element 20.

[0055] As mentioned above, each bipolar plate 2 has at least one opening 18 configured to receive the protruding portion 26 of the voltage monitoring element 20. The voltage monitoring element 20 is configured to be fixed to the bipolar plate 2. In an embodiment not shown, the voltage monitoring element 20 may also be configured to be fixed to or be an integral part of the multilayer membrane electrode assembly 8 of the fuel cell stack 1, and in particular may be part of a subgasket surrounding the multilayer membrane electrode assembly 8.

[0056] In addition to its function as a voltage monitoring element, the voltage monitoring element 20 can also be used for stacking and alignment assistance. To that end, the voltage monitoring element may include structures that allow one voltage monitoring element 20-1 to interact with an adjacent voltage monitoring element 20-2. Figures 7-10 illustrate various embodiments of voltage monitoring elements 20-1, 20-2 with additional alignment mechanisms.

[0057] As shown in Figures 7-9, where such stacking and alignment assistance is provided, the membrane electrode assembly 8 also preferably includes a through-hole 40 through which a portion or portions of the voltage monitoring element 20-1 can extend for interaction with an adjacent voltage monitoring element 20-2.

[0058] Furthermore, for the interaction between two adjacent voltage monitoring elements 20-1, 20-2, it is further preferred that the voltage monitoring element 20 further comprises a recess 36 on the opposite side of the protruding portion, as shown in Figures 7 and 8. In that regard, the size and / or shape and / or depth h of the recess r is further preferably configured to accommodate the protruding portion 26 of an adjacent voltage monitoring element, thereby allowing stacking of the voltage monitoring elements 20-1, 20-2 on top of each other, resulting in automatic alignment of the bipolar plates 2 and membrane electrode assemblies 8 between the layers.

[0059] In Figure 7, a first embodiment is shown, in which the cover part 30 described with reference to Figures 4 to 6 above has a protruding part 38 on its side facing the membrane electrode assembly 8, which extends through a through hole 40 provided in the membrane electrode assembly 8.

[0060] This protruding portion 38-1 is received within a recess 36-2 in the adjacent voltage monitoring element 20-2, allowing alignment of the membrane electrode assembly 8 to the bipolar plate 2, as well as alignment of the bipolar plate 2-1 to the bipolar plate 2-2.

[0061] Figure 2 shows a fuel cell stack 1 according to a second exemplary embodiment. The fuel cell stack 1 of Figure 2 differs from the fuel cell stack 1 of Figure 1 in that the protruding portion 10 of the voltage monitoring and control device 6 has a first portion 17 and a second portion 18, and the second portion 18 is recessed relative to the first portion 17, thereby forming an additional step 20 between the first portion 17 and the second portion 18 of the protruding portion 10.

[0062] As can be further seen in this embodiment, the through-holes 18 and 40 of the bipolar plate 2 and the membrane electrode assembly 8, respectively, may be shaped differently and adapted to the protruding portions 26 and the protruding portions 38, respectively, which further allows for a specific orientation of the bipolar plate 2 and the membrane electrode assembly 8 relative to the voltage monitoring element 20 and therefore relative to each other.

[0063] 8 and 9, the voltage monitoring element 20 extends beyond a single bipolar plate 2 rather than across two bipolar plates 2-1 and 2-2. In that regard, the protruding portion 26 of the voltage monitoring element 20 comprises a first portion 26-1 and a second portion 26-2 that are recessed relative to one another to form a further step 27. As can be further seen, the voltage monitoring element 22 has a first electrical contact element 22-1 at the original step and a second electrical contact element 22-2 at the further step 27, the first electrical contact element being configured to contact the first bipolar plate 2-1 and the second electrical contact element 22-2 being configured to contact the second bipolar plate 2-2.

[0064] Additionally, each bipolar plate 2 has a first opening 18 configured to receive a first portion 26-2 of the protruding portion 26 of the voltage monitoring element 20, and a second opening 19 configured to receive a second portion 26-2 of the protruding portion 26 of the voltage monitoring element 20. The first and second bipolar plates 2-1, 2-2 are arranged such that the first opening 18 of the first bipolar plate 2-1 is aligned with the second opening 19 of the second bipolar plate 2-2.

[0065] Furthermore, as shown, the second portion 26-1 of the protruding portion 26 can be received within the recess 36-2 of the adjacent voltage monitoring element 20-2, thereby enabling automatic alignment of the bipolar plate and the membrane electrode assembly 8. It should be noted that in this embodiment, the membrane electrode assembly 8 further includes two through-holes of different dimensions. Thus, the membrane electrode assembly 8-2 has a through-hole 40 with a first dimension, and the membrane electrode assembly 8-3 has a through-hole 41 with a dimension different from that of the through-hole 40. As with the bipolar plate, the dimensions and shape of the through-holes may be adapted to the dimensions and shape of the first and / or second portions 26-1, 26-2 of the protruding portion 26.

[0066] FIG. 9 shows an embodiment in which the voltage monitoring element 20 provides electrical contact with two plates but does not interact with the adjacent voltage monitoring element 20-2. In this case, every other membrane electrode assembly 8-2, 8-4, etc. only needs to have a through-hole 40 through which the voltage monitoring element 20 can protrude. Furthermore, in this case, alignment of the first and second bipolar plates 2-1, 2-2 is possible because the bipolar plates also have through-holes 18, 19 of different dimensions. The voltage monitoring element 20 provides alignment of the plates relative to each other through the interaction between the dimensions of the protruding portions 26-1, 26-2 and the corresponding through-holes 18, 19 of the bipolar plates 2-1, 2-2. This voltage monitoring element 20 can also make electrical contact with the two bipolar plates 2-1, 2-2 because electrical contact elements 22-1, 22-2 are located on both steps.

[0067] It should be noted that although in Figures 4 to 9 the electrical contact elements 22 are arranged on the steps, it is also possible to arrange the electrical contact elements on any other suitable surface of the voltage monitoring element 20 or the cover portion 30.

[0068] In summary, the disclosed voltage monitoring elements allow for easy and reliable placement of the voltage monitoring elements on the bipolar plates, and furthermore, any misplacement of the electrical contact elements can be avoided, thereby avoiding any damage to the fuel cell stack due to misplacement. [Explanation of symbols]

[0069] 1. Fuel cell stack 2 bipolar plates 4 anode plates 6 cathode plate 8. Membrane Electrode Assembly 10 Protruding part of bipolar plate (bead seal) 12 Bipolar plate base 18;19 Bipolar plate through-holes 20 Voltage Monitoring Elements 22 Electrical Contact Elements 24 base plate 26 Protruding part 28 steps 30 Cover part 32 Hook 34 Cover element connecting element 36 Recess 38 Cover element protrusion 40,41 Membrane electrode assembly through-hole h b Base plate height h p Height of protruding part h c Cover height h ec Electrical Contact Element Height h r Recess depth h シール =D PS Bipolar plate protrusion height D EP Bipolar plate base height H VM Overall height of voltage monitoring element H BPP Overall height of bipolar plate

Claims

1. A battery stack (1) comprising a plurality of electrical plates (2; 4) sandwiching an insulating layer (8), wherein at least one of the electrical plates (2; 4) is provided with a voltage monitoring element (20) for monitoring the voltage of the electrical plate (2; 4), The battery stack (1), characterized in that the at least one electrical plate (2; 4) on which the voltage monitoring element (20) is arranged has at least one through-hole (18; 19), and the voltage monitoring element (20) is arranged on and / or in the through-hole (18; 19).

2. 2. The battery stack (1) according to claim 1, wherein the voltage monitoring element (20) is made of an electrically insulating material and is provided with an electrical contact element (22) made of a conductive material, the electrical contact element (22) being arranged on a surface of the voltage monitoring element (20) and configured to make contact with the electrical plates (2; 4).

3. 3. The battery stack (1) of claim 1 or 2, wherein the voltage monitoring element (20) has a base plate (24) and a protruding portion (26), the protruding portion (26) being recessed from the base plate (24) so ​​as to form a step (28) between the base plate (24) and the protruding portion (26).

4. The height h of the protruding portion (26) of the voltage monitoring element (20) ｐ is the thickness D of the electrical plate (2; 4) ＥＰ is less than (h ｐ <D ＥＰ 4. The battery stack (1) according to claim 3, wherein the battery stack (1) is designed so that:

5. 4. The battery stack (1) of claim 3, wherein the voltage monitoring elements (20) have recesses (36) in the base plate (24) on the opposite side of the protruding portions (26) that are sized to accommodate the protruding portions (26) of adjacent voltage monitoring elements (20), such that one voltage monitoring element (20) is configured to be stacked on top of another voltage monitoring element (20).

6. The height h of the protruding portion (26) of the voltage monitoring element (20) ｐ is the thickness D of the electrical plate (2; 4) ＥＰ becomes larger than (h ｐ >D ＥＰ ) and the depth h of the recess (36) ｒ 6. The cell stack (1) of claim 5, wherein the protruding portion (26) of the voltage monitoring element (20) extends beyond the electrical plates (2; 4).

7. 4. The battery stack (1) according to claim 3, wherein the diameter of the base plate (24) is designed to be larger than the diameter of the through holes (18; 19) of the electrical plates (2; 4) such that a surface of the step (28) at least partially abuts a surface of the electrical plates (2; 4) and the protruding portion (26) extends through the through holes (18; 19) of the electrical plates (2; 4).

8. 4. The battery stack (1) according to claim 3, wherein the voltage monitoring element (20) further comprises a cover portion (30), the diameter of which is larger than the diameter of the through-holes (18; 19) so that the voltage monitoring element (20) is fixed to the electrical plate (2; 4).

9. 9. The battery stack (1) according to claim 8, wherein the cover portion (30) is a separate element configured to interact with the protruding portion (26) of the voltage monitoring element (20) to secure the voltage monitoring element (20) to the electrical plate (2; 4).

10. A battery stack (1) as described in claim 8, wherein the voltage monitoring element (20) is made from an electrically insulating material and is provided with an electrical contact element (22) made from a conductive material, and the electrical contact element (22) is arranged on the base plate (24), on the protruding portion (26) and / or on the cover portion (30) so that the electrical contact element (22) contacts the electrical plates (2; 4).

11. The height D by which the electrical plate (2; 4) protrudes from the base (12) of the electrical plate (2; 4) in the direction of the adjacent insulating layer (8). ＰＳ and the height h of the base plate of the voltage monitoring element is ｂ is the height D of the protruding structure (10) ＰＳ The following is true: ｂ ≦D ＰＳ 4. The battery stack (1) according to claim 3, wherein the battery stack (1) is designed so that:

12. The height D by which the electrical plate (2; 4) protrudes from the base (12) of the electrical plate (2; 4) in the direction of the adjacent insulating layer (8). ＰＳ The height hc of the cover portion (30) of the voltage monitoring element (20) is equal to or greater than the height D of the protruding structure (10). ＰＳ (hc≦D ＰＳ 9. The battery stack (1) according to claim 8, wherein the battery stack (1) is designed so that:

13. 4. The battery stack (1) of claim 3, wherein the protruding portion (26) of the voltage monitoring element (20) has a first portion (26-1) and a second portion (26-2), and the second portion (26-2) is recessed relative to the first portion (26-1), thereby forming a further step between the first and second portions (26-1, 26-2) of the protruding portion (26), and both steps are provided with electrical contact elements (22) configured to contact the electrical plates (2; 4).

14. 2. The battery stack (1) according to claim 1, wherein the electrical plates (2; 4) have first and second through holes (18; 19) on and / or within which the voltage monitoring element (20) is housed, the first and second through holes (18; 19) having different dimensions and / or shapes.

Images