Membrane-electrode unit with sealed frame

Abstract

The present invention relates to a unit comprising a device (1) consisting of two gas diffusion electrodes (2,3) sandwiched between which is a membrane (4), the device (1) being tightly connected by a first seal (5) to a frame (6) surrounding the device (1) on its periphery, the frame (6) having two mutually opposed end faces (7,8), the frame (6) having a tubular aperture (9) extending from its first end face (7) to its second end face (8), the aperture (9) being surrounded by second seals (10.1, 10.2, 10.3, ...) on both sides of the end faces of the frame (6) and sealed to each other during normal use of the unit.

Description

Technical Field

[0001] The present invention relates to a unit provided with a device composed of two gas diffusion electrodes, in which a membrane is arranged in a sandwich shape between the two gas diffusion electrodes, and the device is tightly coupled to a frame surrounding the device at its outer periphery by a first seal, and the frame has two end faces facing each other.

[0002] Prior Art Such a unit is known from German Patent Application Publication No. 102013014083. The unit is a membrane - electrode unit. The device is surrounded at its outer periphery by a frame with a gap therebetween, and a seal is arranged in the gap formed by this interval, and this seal tightly couples the device and the frame. The membrane - electrode unit is provided for use in a fuel cell.

[0003] The frame is also formed in a sandwich shape similar to the device, having two outer frame parts, and an inner frame part is arranged between the two outer frame parts.

[0004] The connection between the device and the frame is performed by applying a pressing process at high temperature. The sealing material of the seal is arranged between the outer frame parts in the pressing direction before the pressing process is executed, thereby defining an interval with respect to the device. During the pressing process, the outer frame parts are continuously moved until they respectively abut against the inner frame part. At this time, the fluid sealing material is pushed into this gap until the gap formed by the above - mentioned interval is sealed and the sealing material penetrates into the boundary of the device with which it contacts. Thereby, the membrane - electrode unit is formed as a composite body composed of the device and the frame using the seal.

[0005] The membrane - electrode unit is held in the frame by a seal.

[0006] Disclosure of the Invention The fundamental problem of the present invention is to improve the type of unit mentioned at the beginning so that the electrochemical cell, particularly the fuel cell, driven in conjunction with the unit has a simpler structure and can be manufactured more easily and at a lower cost.

[0007] The above problems are solved by the features described in claim 1 of the present invention. For advantageous configurations, refer to the claims that directly or indirectly reference claim 1.

[0008] To solve the above problems, a unit is provided comprising a device consisting of two gas diffusion electrodes, wherein a membrane is sandwiched between the two gas diffusion electrodes, the device is tightly coupled to a frame surrounding the device by a first seal, the frame has two mutually opposing end faces, and the frame has a conduit-shaped aperture extending from its first end face to its second end face, the aperture being surrounded on both sides of the frame's end faces by a second seal and sealed to each other during the unit's intended use.

[0009] In this case, the unit is configured to be multifunctional, which is advantageous because it provides another function that enables a low-cost structure with fewer parts for electrochemical cells, such as fuel cells.

[0010] The unit is configured as a membrane-electrode unit.

[0011] Typically, membrane-electrode units, as mentioned at the beginning and known from the prior art, must be sealed within an electrochemical cell, such as a fuel cell, by additionally and separately formed seals. The manufacturing and installation of these seals makes the cell production complex and expensive. Furthermore, errors in the installation of these seals can impair the function of the cell.

[0012] These drawbacks are avoided in the unit according to the present invention. To this end, the frame has a conduit-like aperture extending from its first end face to its second end face, the aperture being surrounded on both sides of the end face of the frame by a second seal.

[0013] The device and the second seal form a pre-assembled unit.

[0014] The aperture in the frame is formed to coincide with the openings in the bipolar plates that are in contact with the end face when the unit is used in a fuel cell, where the openings in the bipolar plates are formed by the inlet and outlet of the refrigerant and the inlet and outlet of the gas.

[0015] The aperture and a second seal that seals it form an integrated component of the unit, which reduces the cost and simplifies the manufacturing and installation of the electrochemical cell.

[0016] Alternatively, a unit may be applied comprising a device consisting of two gas diffusion layers, wherein a catalyst-coated membrane is sandwiched between the two gas diffusion layers, and the device is tightly coupled to a frame surrounding the device by a first seal, the frame having two opposite end faces, the frame having a conduit-like aperture extending from the first end face to the second end face, the aperture being surrounded on both sides of the frame's end faces by a second seal and being sealed to each other during the intended use of the unit.

[0017] In one advantageous configuration, the second seal can be configured to consist of an elastomer sealing material. Elastomer sealing materials are often available at a low cost in many specifications.

[0018] At least two of the second seals, and more preferably all of them, can be formed from a uniform material so as to blend together to form a single unit. In this case, at least two of the second seals, and more preferably all of them, can be manufactured in a single method step, which is advantageous because the unity avoids the risk of transitions between adjacent second seals and the resulting lack of sealing between the second seals.

[0019] The second seal is moldable.

[0020] The frame is preferably formed in a sandwich shape and has two outer frame portions, with an inner frame portion positioned between these two outer frame portions. As mentioned at the beginning, such a frame structure has the advantage that the first seal forms a tight bond between the unit's device and the frame by compression between the outer frame portions.

[0021] The frame structure can be formed from a thermoplastic film material, such as polyester.

[0022] The inner frame portion protrudes beyond the outer frame portion on its outer circumference, thereby forming a protruding portion within the frame. An aperture is located on this protruding portion.

[0023] The second seal is tightly bonded to the inner frame portion, tightly surrounding the aperture while the electrochemical cell using the unit inside is being used as specified.

[0024] To achieve a durable, tight bond between the second seal and the inner frame portion, the second seal is preferably bonded to the inner frame portion by material connection and / or shape connection. For this purpose, the second seal can be configured to be injection-molded integrally with the inner frame portion. This results in a bond by material connection.

[0025] The shape connection between the second seal and the inner frame can be achieved by the inner frame part having a fixing aperture that is penetrated by the seal material of the second seal during manufacturing. This enables easy manufacturing of the second seals arranged on both sides of the end face of the inner frame part.

[0026] The concepts described above are significantly applicable to both fuel cells and electrolytic cells or redox flow batteries.

[0027] Hydrogen and oxygen are supplied to the fuel cell, thereby generating water and energy.

[0028] In contrast, water and energy are supplied to the electrolytic cell, thereby generating hydrogen and oxygen.

[0029] The redox flow battery processes an electrolyte liquid in a chemical reaction (redox reaction), thereby supplying available electrical energy.

[0030] Hereinafter, embodiments of the unit according to the present invention will be described in detail in accordance with FIGS. 1 and 2 which schematically show them.

Brief Description of Drawings

[0031] [Figure 1] FIG. 2 is a schematic cross-sectional view showing the membrane-electrode unit of FIG. 2 cut along line A-B. [Figure 2] FIG. 1 is a plan view showing the unit of FIG. 1.

[0032] Embodiments of the Invention FIGS. 1 and 2 show an embodiment of the unit according to the present invention.

[0033] FIG. 1 shows a cross-sectional view cut along line A-B of FIG. 2.

[0034] The unit comprises a device 1 formed from two gas diffusion electrodes 2 and 3 and a membrane 4, with the membrane 4 sandwiched between the gas diffusion electrodes 2 and 3. The device 1 is surrounded on its outer periphery by a frame 6, where the device 1 is held in a sealed state within the frame 6 by a first seal 5.

[0035] The frame 6 is formed from multiple parts and has two outer frame parts 11 and 12 that form end faces 7 and 8. An inner frame part 13 is sandwiched between the outer frame parts 11 and 12.

[0036] Conduit-shaped apertures 9 are arranged in the inner frame portion 13, and each aperture 9 is formed to jointly overlap the inlet and outlet portions of the bipolar plates of the electrochemical cell, in this case the fuel cell stack, which are not shown in Figure 1. Second seals 10.1, 10.2, 10.3, ... are arranged around the apertures 9, and these second seals 10.1, 10.2, 10.3, ... are formed of a uniform material so that they blend together to form a single unit. The second seals 10.1, 10.2, 10.3, ... are located on both sides of the end face of the frame 6 and seal the apertures 9 together while the unit is being used as specified, i.e., when the unit is assembled.

[0037] The inner frame portion 13 is provided with fixing apertures 14 that are penetrated by the sealing material of the second seals 10.1, 10.2, 10.3,… This allows the second seals 10.1, 10.2, 10.3,… to be easily attached to both sides of the end face of the frame 6. On the other hand, it provides a durable and tight bond of the second seals 10.1, 10.2, 10.3,… in the inner frame portion 13 over a long period of use.

[0038] Figure 2 shows a plan view of the unit in Figure 1. The outer frame portions 11 and 12 surround the outer periphery of the device 1, and in this case, the inner frame portion 13, which is positioned between the outer frame portions 11 and 12 in the plan view of the figure, protrudes beyond the outer frame portions 11 and 12 in the periphery. An aperture 9 is positioned at this protrusion of the inner frame portion 13, and the aperture 9 is surrounded on both sides of the end face of the inner frame portion by second seals 10.1, 10.2, 10.3, ... which are formed integrally with each other, as shown in Figure 1.

Claims

1. A unit comprising a device (1) consisting of two gas diffusion electrodes (2, 3), A membrane (4) is sandwiched between the two gas diffusion electrodes (2, 3). The device (1) is tightly coupled to a frame (6) that surrounds the device (1) on its outer circumference by a first seal (5). The frame (6) has two end faces (7, 8) that face each other, In the unit, the frame (6) has a conduit-shaped aperture (9) extending from its first end face (7) to its second end face (8), The aperture (9) is surrounded on both sides of the end face of the frame (6) by second seals (10.1, 10.2, 10.3, ...) and is sealed to each other during the specified use of the unit, the frame (6) is formed from a plurality of parts and includes two outer frame parts (11, 12), the inner frame part (13) is sandwiched between the outer frame parts (11, 12), the inner frame part (13) has a fixing aperture (14) that is penetrated during manufacturing by the sealing material of the second seal, the device (1) is held in a sealed state within the frame (6) by the first seal (5), the first seal is compressed between the two outer frame parts, A unit characterized by the following features.

2. A unit comprising a device (1) consisting of two gas diffusion layers (2, 3), A catalyst-coated membrane (4) is sandwiched between the two gas diffusion layers (2, 3). The device (1) is tightly coupled to a frame (6) that surrounds the device (1) on its outer circumference by a first seal (5). The frame (6) has two end faces (7, 8) that face each other, In the unit, the frame (6) has a conduit-shaped aperture (9) extending from its first end face (7) to its second end face (8), The aperture (9) is surrounded on both sides of the end face of the frame (6) by second seals (10.1, 10.2, 10.3, ...) and is sealed to each other during the specified use of the unit, the frame (6) is formed from a plurality of parts and includes two outer frame parts (11, 12), an inner frame part (13) sandwiched between the outer frame parts (11, 12), the inner frame part (13) has a fixing aperture (14) that is penetrated during manufacturing by the sealing material of the second seal, the device (1) is held in a sealed state within the frame (6) by the first seal (5), the first seal is compressed between the two outer frame parts, unit.

3. The unit according to claim 1 or 2, wherein the second seals (10.1, 10.2, 10.3, ...) are made of an elastomer seal material.

4. The unit according to claim 1 or 2, wherein at least two of the second seals (10.1, 10.2, 10.3, ...) are formed of a uniform material so as to blend together to form a single unit.

5. The unit according to claim 1 or 2, wherein all of the second seals (10.1, 10.2, 10.3, ...) are formed of a uniform material so as to mix with each other and become a single unit.

6. The unit according to claim 1 or 2, wherein the frame (6) is formed in a sandwich-like manner.

7. The unit according to claim 6, wherein the frame (6) has two outer frame portions (11, 12), and an inner frame portion (13) is disposed between the two outer frame portions (11, 12).

8. The unit according to claim 7, wherein the aperture (9) is located only in the inner frame portion (13).

9. The unit according to claim 7, wherein the second seals (10.1, 10.2, 10.3, ...) are tightly bonded to the inner frame portion (13) and tightly surround the aperture (9).

10. The unit according to claim 9, wherein the second seals (10.1, 10.2, 10.3, ...) and the inner frame portion (13) are joined by material connection and / or shape connection.

11. The unit according to claim 7, wherein the inner frame portion (13) has a fixing aperture (14) that is penetrated by the sealing material of the second seal (10.1, 10.2, 10.3, ...).

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