Fuel cell assembly, fuel cell device and motor vehicle

Abstract

Fuel cell arrangement (1) with a fuel cell stack (2) comprising at least a plurality of fuel cells (3) arranged between two end plates (4), wherein the fuel cell stack (2) has an intermediate plate (5) arranged between the fuel cells (3), which is attached to a fastening element (7) of the fuel cell arrangement (1) by means of at least one fixed bearing (6) perpendicular to a stacking direction of the fuel cells (3), wherein the fastening element (7) is a fuel cell stack housing (8) in which the fuel cell stack (2) is arranged, characterized in that the intermediate plate (5) is attached to an inner wall (9) of the fuel cell stack housing (8) by means of two fixed bearings (6), wherein the two fixed bearings (6) are arranged on opposite end faces of the intermediate plate (5),and that the two end plates (4) are each attached to the inner wall (9) of the fuel cell stack housing (8) by means of two fixed bearings (6'), the fixed bearings (6') being arranged on opposite end faces of the end plates (4).

Description

[0001] The invention relates to a fuel cell arrangement with a fuel cell stack consisting at least of a plurality of fuel cells arranged between two end plates.

[0002] Furthermore, the invention relates to a fuel cell device with such a fuel cell arrangement and to a motor vehicle with the aforementioned fuel cell device.

[0003] Fuel cells are used to generate electrical energy from an electrochemical reaction in which a fuel, usually hydrogen, reacts with an oxidant, typically oxygen taken from the air. Fuel cells contain an electrolyte as their core component and associated electrodes, forming an anode and a cathode. To increase power output, multiple fuel cells can be combined into a fuel cell stack, particularly to meet the power requirements of motor vehicles. During operation of a fuel cell stack, the fuel, especially hydrogen (H₂) or a hydrogen-containing gas mixture, is supplied to the anode. In the case of a hydrogen-containing gas, it is first reformed to produce hydrogen. At the anode, an electrochemical oxidation of H₂ to H₂ takes place. +The process takes place with the release of electrons. The electrons produced at the anode are transferred to the cathode via an electrical conductor. Oxygen or an oxygen-containing gas mixture is supplied to the cathode, resulting in the reduction of O₂ to O₂. 2- This process takes place with the uptake of electrons. These oxidation and reduction products from the anode and cathode then react to form H₂O. The energy released by the electrochemical reaction described above can then be used in the form of electrical energy to power the motor vehicle.

[0004] However, with known fuel cell configurations, a problem arises: the fuel cell stack often tends to deflect during construction. The risk of deflection increases with the size or length of the fuel cell stack, i.e., with an increasing number of fuel cells arranged in series. Furthermore, even during normal operation of the fuel cell configuration, shock and vibration movements can cause further minor displacements of the fuel cells relative to each other, leading to further deflection of the fuel cell stack.

[0005] In the intended use of the fuel cell arrangement, the fuel cell stack is typically arranged in a fuel cell stack housing. Unfortunately, the problem discussed above means that, in known fuel cell arrangements, the fuel cell stack must maintain a certain distance from the fuel cell stack housing for insulation reasons, thus requiring more installation space.

[0006] WO 2013 / 053 374 A1 discloses a structure of a fuel cell stack, wherein the structure has a fuel cell stack housing with two outer and one central reinforcing rib.

[0007] WO 2004 / 075 330 A1 discloses an end plate for a fuel cell stack, wherein the end plate is structurally designed for a uniform pressure load.

[0008] German patent DE 10 2010 051 753 A1 describes a fuel cell arrangement that provides for horizontal storage of the fuel cell stack. This document describes various methods for reducing stack deflection.

[0009] The object of the present invention is to provide a fuel cell arrangement that is improved with respect to the aforementioned problem.

[0010] The problem is solved by the fuel cell arrangement with the features of claim 1, the fuel cell device with the features of claim 5 and the motor vehicle with the features of claim 6.

[0011] The fuel cell arrangement with the features of claim 1 is characterized in that the fuel cell stack has an intermediate plate arranged between the fuel cells, which can be attached or is attached to a fastening element of the fuel cell arrangement by means of at least one fixed bearing perpendicular to a stacking direction of the fuel cells. In the fuel cell arrangement according to the invention, the intermediate plate is thus arranged within the fuel cell stack, i.e., in the area between the end plates between the fuel cells located therein, and can be fixed to the fastening element at this position or is fixed in place during intended use of the fuel cell arrangement.

[0012] The intermediate plate advantageously stiffens the fuel cell arrangement or fuel cell stack, thus ensuring a particularly significant reduction in deflection. This offers the further advantage that longer fuel cell stacks or corresponding cell rows can also be realized, with the intermediate plate according to the invention reliably guaranteeing the mechanical stability of the fuel cell stack.

[0013] According to the invention, the intermediate plate can be attached to one and / or at least one further fastening element by means of several fixed bearings perpendicular to the stacking direction, or is attached during the intended use of the fuel cell arrangement.

[0014] According to the invention, the fastening element is a fuel cell stack housing in which the fuel cell stack is arranged. The intermediate plate can therefore be attached to the fuel cell stack housing, preferably to an inner wall of the fuel cell stack housing associated with the fuel cell stack, or is attached during the intended use of the fuel cell arrangement. By attaching the intermediate plate or the fuel cell stack directly to the fuel cell stack housing, additional installation space can advantageously be saved. Furthermore, no separate fastening element requiring installation space is necessary.

[0015] It is particularly preferred that the intermediate plate is arranged in the middle of the fuel cell stack. In other words, the intermediate plate is equidistant from both end plates, or there are the same number of fuel cells between the first end plate and the intermediate plate as between the intermediate plate and the second end plate. Advantageously, this optimally distributes the pressure load on the fuel cell stack and thus significantly reduces the risk of deflection. Alternatively, depending on the actual design of the fuel cell arrangement, it is of course also conceivable to arrange the intermediate plate in a different position. This allows the advantages of the intermediate plate to be optimally tailored to the specific design of the fuel cell arrangement.

[0016] According to the invention, the end plates can each be attached to or fastened to the fastening element, in particular the fuel cell stack housing, by means of at least one further fixed bearing. This further improves the mechanical stability of the fuel cell arrangement and consequently further reduces the risk of deflection of the fuel cell stack. In particular, the end plates can each be attached or fastened by means of several further fixed bearings.

[0017] Preferably, the intermediate plate is made of a rigid material. The selection of the appropriate material is preferably based on the expected mechanical loads on the fuel cell arrangement or fuel cell stack. This advantageously further improves the mechanical stability of the fuel cell arrangement.

[0018] In particular, it is provided that the intermediate plate and / or the end plates are detachably attached to the fastening element, especially the fuel cell stack housing, by means of the respective fixed bearing. This offers the advantage that, if necessary, for example for maintenance purposes, the fuel cell assembly can be easily and non-destructively disassembled.

[0019] The fuel cell device with the features of claim 5 is characterized in that the fuel cell arrangement is designed according to the invention, as already described above. The advantages already mentioned in this regard result.

[0020] The motor vehicle with the features of claim 6 comprises a fuel cell device designed according to the invention, as described above. The advantages already mentioned in this regard also apply here.

[0021] Preferred features and combinations of features result in particular from the above description and the claims.

[0022] The invention will now be explained in more detail with reference to the drawing. The drawing shows: Fig. 1 A simplified schematic cross-sectional representation of an advantageous fuel cell arrangement.

[0023] Fig. Figure 1 shows a simplified schematic representation of a cross-section through an advantageous fuel cell arrangement 1 with a fuel cell stack 2.

[0024] Fuel cell stack 2 comprises a plurality of fuel cells 3 stacked on top of or next to each other in one stacking direction. For clarity, in Fig. 1. Not all fuel cells 3 are labelled with a reference numeral. The stacked fuel cells 3 are arranged within the fuel cell stack 2 between two end plates 4, which thus define the boundaries of the fuel cell stack 2. Optionally, the end plates 4 may have media connections (not shown here for clarity) to supply the fuel cells 3 with media.

[0025] During the construction of the fuel cell stack 2 and during subsequent use, shock and vibration movements as well as the length of the fuel cell stack 2 can cause displacements of the fuel cells 3 relative to each other and thus a bending of the fuel cell stack 2.

[0026] To avoid or at least reduce this deflection, the present fuel cell arrangement 1 advantageously provides that the fuel cell stack 2 has an intermediate plate 5 arranged between the fuel cells 3. For mechanical stabilization of the fuel cell stack 2, the intermediate plate 5 is attached to a fastening element 7 of the fuel cell arrangement 1 by means of at least one fixed bearing 6 perpendicular to the stacking direction of the fuel cells 3.

[0027] In this case, the fastening element 7 is a fuel cell stack housing 8 of the fuel cell arrangement 1, in which the fuel cell stack 2 is arranged. According to the present embodiment, the intermediate plate 5 is attached to an inner wall 9 of the fuel cell stack housing 8 by means of two fixed bearings 6, the two fixed bearings 6 being arranged on opposite end faces of the intermediate plate 5.

[0028] This mechanical fastening transfers the pressure load acting on the fuel cell stack 2 to the fuel cell stack housing 8 via the intermediate plate 5, thus advantageously ensuring a lower deflection of the fuel cell stack 2.

[0029] According to the present embodiment, the intermediate plate 5 is, as shown in Fig. As can be clearly seen, the intermediate plate 5 is arranged in the middle of the fuel cell stack 2. In other words, the intermediate plate 5 is equidistant from the end plates 4, or there are as many fuel cells 3 (for example, fifty fuel cells 3) between one end plate 4 and the intermediate plate 5 as there are between the intermediate plate 5 and the other end plate 4.

[0030] Alternatively, according to embodiments not shown here, the intermediate plate 5 can also be arranged off-center, i.e., the distance of the intermediate plate 5 to one end plate 4 differs from the distance of the intermediate plate 5 to the other end plate 4. Preferably, the position or arrangement of the intermediate plate 5 within the fuel cell stack 2 is selected depending on the expected mechanical loads of the fuel cell arrangement 1.

[0031] Preferably, the intermediate plate 5 is made of a rigid material to ensure its mechanical stability even under high pressure loads. The material is preferably selected based on the expected pressure loads on the fuel cell stack 2.

[0032] According to the present embodiment, the two end plates 4 are advantageously also each attached to the fastening element 7 or, in this case, to the fuel cell stack housing 8 by means of at least one further fixed bearing 6', in this case, by means of two further fixed bearings 6' (analogous to the intermediate plate 5). This further improves the mechanical stability of the fuel cell stack 2. Preferably, the fixed bearings 6 and the further fixed bearings 6' are identical. Alternatively, the fixed bearings 6 and the further fixed bearings 6' can, of course, differ in their design.

[0033] In this case, the intermediate plate 5 and the end plates 4 are detachably attached to the fuel cell stack housing 8 by means of the respective fixed bearings 6, 6', in order to be able to easily and, above all, non-destructively disassemble the fuel cell assembly 1 if necessary, for example for maintenance purposes. In this respect, the fuel cell stack housing 8 can be opened non-destructively, for which purpose it has, for example, a cover element (not shown) or an opening mechanism. REFERENCE MARK LIST: 1 Fuel cell arrangement 2 fuel cell stacks 3 fuel cells 4 end plates (rigid) 5 intermediate plate (rigid) 6 fixed bearings 6' further fixed camp 7 Fastening element 8 fuel cell stack housings 9 Interior wall

Claims

[1] Fuel cell arrangement (1) with a fuel cell stack (2) comprising at least a plurality of fuel cells (3) arranged between two end plates (4), wherein the fuel cell stack (2) has an intermediate plate (5) arranged between the fuel cells (3), which is attached to a fastening element (7) of the fuel cell arrangement (1) by means of at least one fixed bearing (6) perpendicular to a stacking direction of the fuel cells (3), wherein the fastening element (7) is a fuel cell stack housing (8) in which the fuel cell stack (2) is arranged, characterized by, that the intermediate plate (5) is attached to an inner wall (9) of the fuel cell stack housing (8) by means of two fixed bearings (6), wherein the two fixed bearings (6) are arranged on opposite end faces of the intermediate plate (5), and that the two end plates (4) are also each attached to the inner wall (9) of the fuel cell stack housing (8) by means of two fixed bearings (6'), wherein the fixed bearings (6') are arranged on opposite end faces of the end plates (4). [2] Fuel cell arrangement according to one of the preceding claims, characterized by , that the intermediate plate (5) is arranged in the middle of the fuel cell stack (2). [3] Fuel cell arrangement according to one of the preceding claims, characterized by , that the intermediate plate (5) is made of a rigid material. [4] Fuel cell arrangement according to one of the preceding claims, characterized by, that the intermediate plate (5) and / or the end plates (4) are detachably attached to the fastening element (7) by the respective fixed bearing (6, 6'). [5] Fuel cell device with a fuel cell assembly (1), characterized by a design of the fuel cell arrangement (1) according to one of claims 1 to 4. [6] Motor vehicle with a fuel cell device according to claim 5.

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