Fraunhofer Institute for Solar Energy Systems ISEThe R2MEA project investigated innovative production processes for manufacturing the core component of fuel cells, the membrane electrode assembly (MEA). Laboratory processes and, in particular, industrial roll-to-roll processes were examined. “R2MEA” is a subproject of the joint project “H2GO – National Action Plan for Fuel Cell Production” involving 19 Fraunhofer Institutes to promote the ramp-up of fuel cell production especially for heavy-duty transport in Germany.
Series Production of Mobile Fuel Cells: Research Platform for Roll-to-Roll Production of MEAs
R2MEA
The catalyst ink is applied via slot die coating on a decal foil within the roll-to-roll coating line.
Initial Situation
In addition to battery-electric drive trains, low-temperature fuel cells are also an opportunity for the heavy-duty and commercial vehicle sector to switch to emission-free drives. The expected production volume for the MEA, is 8 million units per year for 20,000 trucks with 400 cells each, which is not achievable with today's manufacturing processes. In order to meet market expectations, existing plant concepts must therefore be adapted and scalable production methods developed.
Objective
In order to support component manufacturers and machine and plant builders in scaling up fuel cell production, the “R2MEA” research consortium, coordinated by Fraunhofer ISE, investigated manufacturing processes and components. Fraunhofer ISE developed a research platform that is available to companies for production issues ranging from catalyst ink production to full format 7-layer MEAs (i.e., the composite of membrane, catalyst layers, subgaskets, and gas diffusion layers).
The joint project is aiming at companies throughout the entire value chain of fuel cell MEA production – from manufacturing technology and mechanical and plant engineering to vehicle-side applications in heavy-duty transport.
Approach
The following questions were addressed within the framework of “R2MEA”:
- In addition to slot die coating, which is primarily used today - are rotary printing processes also useful for applying catalyst layers?
- Is direct printing on the membrane possible with the required high quality?
- How can the membrane, catalyst layers, subgaskets, and gas diffusion layers be cut to size in roll-to-roll processes?
- Which positioning and lamination processes are suitable for producing high-quality components from the individual layers?
5-Layer MEAs with the format of the Generic Stack are assembled in a roll-to-roll process and kiss-cutted on a carrier foil.
Results
In “R2MEA” innovative production processes and new plant concepts were developed for membrane coating and drying using transfer route or direct coating, application of subgaskets, and cutting of the gas diffusion layer as a high-speed roll-to-roll process. In addition, industrial processes for the production of catalyst inks were investigated. To this end, the entire production chain is available on pilot plant machines in a technical center at Fraunhofer ISE.
Additionally, Fraunhofer ISE conducted extensive techno-economic analyses of the economic efficiency of various production processes as well as life cycle assessments of their ecological footprint. For example, the establishment of innovative coating processes that enable direct coating of the membrane instead of the usual transfer process contributes to cost reduction due to more efficient use of materials and improved electrochemical performance.
Funding
The “R2MEA” project is funded by the Federal Ministry of Economic Affairs and Energy (BMWE).
