RU2842269C2 - Membrane-electrode unit with frame seal - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering, specifically to a membrane-electrode unit with frame seal, and can be used in fuel cell assemblies. Unit, which includes system (1) of two gas diffusion electrodes (2, 3), between which membrane (4) is sandwiched, is sealed by first seal (5) along the outer perimeter of frame (6), frame has two opposite to each other end sides (7, 8), and is also provided with channel openings (9), which extend from first (7) to second end side (8) of frame (6), wherein said openings (9) on the end side on both sides of frame (6) are covered by second seals (10.1, 10.2, 10.3...) and are sealed relative to each other during the intended use of the unit. When using the unit in the fuel cell frame openings are made congruent with the adjacent from the end side on both sides bipolar plates holes, wherein said openings in the bipolar plates are formed by coolant inlets and outlets, as well as gas inlets and outlets.

EFFECT: longer service life of the membrane-electrode unit due to formation of a reliable and durable seal.

11 cl, 2 dwg

Description

The invention concerns a unit that includes a system of two gas diffusion electrodes, between which a membrane is sandwiched, wherein this system is tightly connected by means of a first seal to a frame that encloses the system along the outer perimeter, and wherein the frame has two end faces opposite each other.

Such a unit is known from DE 102013014083 A1. This unit is a membrane-electrode unit. The system is surrounded by a frame along the outer perimeter at a distance, and in the gap formed by this distance a seal is located, which tightly connects the system and the frame. This membrane-electrode unit is intended for a fuel cell.

The frame, like the system, has a sandwich-type design and includes two outer frame parts, between which the inner frame part is located.

The connection of the system to the frame is carried out using a pressing process at elevated temperature. Before the pressing process, the sealing material of the seal is placed in the pressing direction between the outer parts of the frame and limits the distance to the system with them. During the pressing process, the outer parts of the frame move towards each other until each of them contacts, adjacently, the inner part of the frame. In this case, the fluid sealing material is pressed into the gap forming the distance until the gap is compacted and the sealing material penetrates the limitation of the adjacent system. In this way, the membrane-electrode unit is formed as a complex of the system and the frame by means of compaction.

The membrane-electrode unit is held by a seal inside the frame.

The invention is based on the task of improving the above-mentioned type of block in such a way that the electrochemical cell used with it, in particular the fuel cell, has a more simplified design and is even simpler and more economical to manufacture.

This task is solved in accordance with the invention by the features of claim 1. The preferred embodiments are referred to in claims directly or indirectly dependent on claim 1.

To solve the problem, a block is provided, which includes a system of two gas diffusion electrodes, between which a membrane is sandwiched, wherein this system is tightly connected by means of a first seal to a frame enclosing the system along the outer perimeter, and wherein the frame has two end sides opposite each other, wherein the frame has channel openings that extend from the first end side to the second end side of the frame, and wherein these openings on the end side on both sides of the frame are covered by second seals and are sealed relative to each other during the use of the block for its intended purpose.

It is preferable that the block is multifunctional and therefore has other functions that make it possible to design an electrochemical cell, such as a fuel cell, with a small number of parts and in an economical manner.

The block is made in the form of a membrane-electrode block.

Typically, the membrane-electrode unit, which is known from the prior art and has already been described, must be sealed within an electrochemical cell, such as a fuel cell, by means of additional and separately created seals. Due to the manufacture and installation of the seals, the manufacture of the cell is labor-intensive and expensive. In addition, the function of the cell can be negatively affected by installation errors of these other seals.

The block proposed by the invention avoids these disadvantages. For this purpose, the frame includes channel openings that extend from the first to the second end side of the frame, and these openings are covered by second seals on the end side on both sides of the frame.

The system and second seals form a pre-assembled unit.

The openings in the frame, when using the block in a fuel cell, are made congruent with the openings in the bipolar plates adjacent to the end side on both sides, and these openings in the bipolar plates are formed by inlets and outlets for the coolant, as well as inlets and outlets for the gas.

Due to the fact that the openings and the second seals sealing these openings form an integral part of the block, the manufacture and installation of the electrochemical cell is economical and simplified.

Alternatively, a block may be used that includes a system of two gas diffusion layers, between which a membrane coated with a catalyst is sandwiched, wherein this system is sealedly connected to a frame enclosing the system along the outer perimeter by means of a first seal, wherein the frame has two end sides opposite each other, wherein the frame has channel openings that extend from the first end side to the second end side of the frame, and wherein these openings on the end side on both sides of the frame are covered by second seals and are sealed relative to each other during the intended use of the block.

According to one preferred embodiment, it can be provided that the second seals consist of an elastomeric sealing material. Elastomeric sealing materials are available in many specifications, often at low cost.

At least two, preferably all of the second seals can be made to flow seamlessly into one another and from a single material. It is preferable that the at least two, also preferably all of the seals can be manufactured in only one process step, and that, due to the seamlessness, transitions between adjacent second seals and the associated risk of leaks between the second seals are prevented.

The second seals can be profiled.

The frame is preferably made as a sandwich and includes two outer frame parts, between which the inner frame part is located. Such a frame design has, as already described, the advantage that the first seal, due to pressing between the outer frame parts, creates a sealed connection between the system and the block frame.

The frame structure may consist, for example, of a thermoplastic film material such as polyester.

The inner part of the frame along the outer perimeter projects beyond the outer parts of the frame and thus forms a protruding part on the frame. In this protruding part there are openings.

The second seals are sealed to the inside of the frame and sealed to fit the openings during intended use of the electrochemical cell in which the unit is used.

In order to achieve a durable and tight connection between the second seals and the inner part of the frame, the second seals are preferably connected to the inner part of the frame with a material lock and/or with a geometric lock. For this purpose, it can be provided that the second seals are cast under pressure to the inner part of the frame. In this way, a connection with a material lock is achieved.

The geometric locking between the second seals and the inner frame can be achieved by the fact that the inner part of the frame has fastening openings that are penetrated by the sealing material of the second seals in a technologically determined manner. Thanks to this, the second seals can be easily manufactured, which are located on the end side on both sides of the inner part of the frame.

The concept described earlier is useful for both fuel cells and electrolyzers or redox flow batteries.

Hydrogen and oxygen are fed into the fuel cell, creating water and energy.

In contrast, an electrolyzer is fed with water and energy, producing hydrogen and oxygen.

A redox flow battery converts electrolytic fluids into a chemical reaction (redox reaction; oxidation-reduction reaction) that produces useful electrical energy.

An example of the implementation of the block proposed by the invention is described in more detail below in the schematically depicted Figs. 1 and 2.

They show:

Fig. 1: schematic section of the membrane-electrode unit in accordance with Fig. 2 along line A-B;

Fig.2: block from Fig.1 in plan view.

Fig. 1 and 2 show an example of the implementation of the block proposed by the invention.

Figure 1 shows a section A-B from Figure 2.

The unit includes a system 1, which is formed from two gas diffusion electrodes 2, 3 and a membrane 4, wherein the membrane 4 is located between the gas diffusion electrodes 2, 3 in a sandwich-like manner. The system 1 is covered along the outer perimeter by a frame 6, wherein the system 1 is tightly held in the frame 6 by means of the first seal 5.

Frame 6 is made composite and includes two outer frame parts 11, 12, which form end sides 7, 8. Between outer frame parts 11, 12, an inner frame part 13 is located like a sandwich.

In the inner part 13 of the frame there are channel openings 9, which are made congruent with the inlets and outlets of the bipolar plates of the electrochemical cell, here a stack of fuel cells, which are not shown here. Around the openings 9 there are second seals 10.1, 10.2, 10.3, ..., and they are made, passing into each other as a single whole, and from a single material. The second seals 10.1, 10.2, 10.3, ... are located on the end side on both sides of the frame 6 and seal the openings 9 during the use of the unit for its intended purpose, that is, in its built-in state, relative to each other.

The inner part 13 of the frame is provided with fastening openings 14, which are penetrated by the sealing material of the second seals 10.1, 10.2, 10.3, .... Due to this, on the one hand, the second seals 10.1, 10.2, 10.3, ... can be easily installed from the end side on both sides of the frame 6. On the other hand, due to this, a durable and tight connection of the second seals 10.1, 10.2, 10.3, ... on the inner part 13 of the frame is obtained during a long service life.

Fig. 2 shows a plan view of the block of Fig. 1. The outer parts 11, 12 of the frame embrace the system 1 along the outer perimeter, wherein the inner part 13 of the frame, which is located in the plane of the drawing between the outer parts 11, 12 of the frame, projects along the perimeter beyond the outer parts 11, 12 of the frame. In this protruding part of the inner part 13 of the frame, openings 9 are located, which are embraced by second seals 10.1, 10.2, 10.3, ... made in one piece with each other on the end side on both sides of the inner part of the frame, as shown in Fig. 1.

Claims (11)

1. A membrane-electrode unit with a frame seal, comprising a system (1) of two gas diffusion electrodes (2, 3), between which a membrane (4) is sandwiched, wherein this system (1) is sealedly connected by means of a first seal (5) to a frame (6) enclosing the system (1) along the outer perimeter, and wherein the frame (6) has two end sides (7, 8) opposite each other, wherein the frame (6) has channel openings (9) that extend from the first end side (7) to the second end side (8) of the frame (6), characterized in that said openings (9) on the end side on both sides of the frame (6) are covered by second seals (10.1, 10.2, 10.3...) and are sealed relative to each other during the intended use of the unit, wherein the system (1) is sealed is held in the frame (6) by means of the first seal (5). 2. A membrane-electrode unit with a frame seal, comprising a system (1) of two gas diffusion layers (2, 3), between which a membrane (4) coated with a catalyst is sandwiched, wherein this system (1) is sealedly connected to a frame (6) enclosing the system (1) along the outer perimeter by means of a first seal (5), and wherein the frame (6) has two end sides (7, 8) opposite each other, wherein the frame (6) has channel openings (9) that extend from the first end side (7) to the second end side (8) of the frame (6), characterized in that said openings (9) on the end side on both sides of the frame (6) are covered by second seals (10.1, 10.2, 10.3, ...) and are sealed relative to each other during the intended use of the unit, wherein the system (1) is held tightly in the frame (6) by means of the first seal (5). 3. The unit according to item 1 or 2, characterized in that the second seals (10.1, 10.2, 10.3, …) consist of an elastomeric sealing material. 4. A block according to one of paragraphs 1-3, characterized in that at least two (10.1, 10.2) of the second seals (10.1, 10.2, 10.3, ...) are made as a single unit, merging into each other, and from a single material. 5. A block according to one of paragraphs 1-4, characterized in that all second seals (10.1, 10.2, 10.3, ...) are made as a single unit, flowing into each other, and from a single material. 6. A block according to item 1 or 2, characterized in that the frame (6) is made as a sandwich. 7. The block according to item 6, characterized in that the frame (6) has two outer frame parts (11, 12), between which the inner frame part (13) is located. 8. A block according to one of paragraphs 1-7, characterized in that the openings (9) are located only in the inner part (13) of the frame. 9. A block according to one of paragraphs 1-8, characterized in that the second seals (10.1, 10.2, 10.3, ...) are tightly connected to the inner part (13) of the frame and tightly cover the openings (9). 10. The block according to item 9, characterized in that the second seals (10.1, 10.2, 10.3, …) and the inner part (13) of the frame are connected with a material lock and/or with a geometric lock. 11. A block according to one of paragraphs 7-10, characterized in that the inner part (13) of the frame has fastening openings (14) that are penetrated by the sealing material of the second seals (10.1, 10.2, 10.3, ...).