# US 2021/0280885 A1 · Method for manufacturing a membrane assembly for a fuel cell with catalyst free edge areas; membrane assembly and fuel cell with membrane assembly

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- Number: US 2021/0280885 A1
- Document ID: US20210280885A1
- Status: Published application
- Kind: A1
- Application number: 16/812,655
- Filed: 2020-03-09
- Published: 2021-09-09
- Earliest claimed: 2020-03-09
- Assignees: Daimler AG; Ford Motor Company
- Applicants: Daimler AG; Ford Motor Company
- Inventors: Sebastian Prass; Manpal Ghuman; Andrew Leow; Jennie Eastcott; Owen Thomas
- Web page: https://patentgrep.com/patent/US20210280885A1

## CPC

- H01M 8/1004: characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence)
- H01M 4/881: {Electrolytic membranes}
- H01M 4/8814: {Temporary supports, e.g. decal}
- H01M 4/8896: {Pressing, rolling, calendering (membrane electrode assemblies H01M8/1004)}
- H01M 2008/1095: {Fuel cells with polymeric electrolytes}
- Y02E 60/50: Fuel cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A method for manufacturing a membrane assembly for a fuel cell. To overcome a problem of chemical degradation at an edge of the membrane, the method comprises the following steps: positioning a first decal layer, which is made of the same material as a first catalyst layer, on a first side of the membrane, positioning a second decal layer, which is made of the same material as a second catalyst layer, on a second side of the membrane, pressing a compression pad, which is positioned on the first decal layer with the first decal layer and the second decal layer fully overlapping the compression pad, and the second decal layer against each other with the first decal layer and the membrane positioned in-between, whereby pressure on the first and the second decal layer is applied only in an area covered by the compression pad.

## Claims

### Claim 1

A method for manufacturing a membrane assembly for a fuel cell, which membrane assembly comprises
a membrane with a first side and a second side, and
a first catalyst layer arranged on the first side of the membrane and a second catalyst layer arranged on the second side of the membrane, wherein
the first catalyst layer and the second catalyst are at least substantially fully overlapping each other with respect to their extension parallel to the membrane,
wherein the method comprises the following steps forming the first catalyst layer and the second catalyst layer:
positioning a first decal layer, which is made of the same material as the first catalyst layer, on the first side of the membrane,
positioning a second decal layer, which is made of the same material as the second catalyst layer, on the second side of the membrane,
pressing a compression pad, which is positioned on the first decal layer with respective projections of the first decal layer and the second decal layer into a surface of the compression pad fully overlapping the compression pad, and the second decal layer against each other with the first decal layer and the membrane positioned in-between, whereby pressure on the first and the second decal layer is applied only in an area covered by the compression pad.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the pressing is carried out with two pressing surfaces both overlapping the compression pad.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the pressing is carried out in a continuous process by two rollers pressing the compression pad and the second decal layer against each other.

### Claim 4 (depends on 2)

The method according to claim 2, wherein the compression pad is a protruding part of one of the two pressing surfaces or one of the two rollers.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the first decal layer forms the first catalyst layer only in an area of the first side of the membrane which is overlapped by the compression pad during the step of pressing the compression pad and the second decal layer against each other, and/or the second decal layer forms the second catalyst layer only in an area of the second side of the membrane which is overlapped by the compression pad during the step of pressing the compression pad and the second decal layer against each other.

### Claim 6 (depends on 1)

The method according to claim 1, wherein due to a size and/or the positioning of the compression pad relative to the membrane an edge region of the membrane remains free from the first catalyst layer and/or the second catalyst layer.

### Claim 7

A membrane assembly for a fuel cell, comprising
a membrane with a first side and a second side, and
a first catalyst layer arranged on the first side of the membrane and a second catalyst layer arranged on the second side of the membrane, wherein
the first catalyst layer and the second catalyst are at least substantially fully overlapping each other with respect to their extension parallel to the membrane,
wherein
the first catalyst layer is formed from a first decal layer made of the same material as the first catalyst layer by decal transfer and the second catalyst layer is formed from a second decal layer made of the same material as the second catalyst layer by decal transfer, and
the first and the second catalyst layer are formed by pressing a compression pad, which is fully overlapped by respective projections of the first decal layer and the second decal layer into a surface of the compression pad, and the second decal layer against each other with the first decal layer and the membrane positioned in-between, whereby pressure is applied only in an area covered by the compression pad.

### Claim 8 (depends on 7)

The membrane assembly according to claim 7, wherein an edge region of the membrane is free from the first catalyst layer and/or the second catalyst layer.

### Claim 9 (depends on 7)

The membrane assembly according to claim 7, wherein the first catalyst layer and the second catalyst layer form an electrode each.

### Claim 10 (depends on 7)

A fuel cell with at least one membrane assembly according to claim 7.