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Mass Manufacture of MEAs Using High Speed Deposition Processes

Periodic Reporting for period 2 - MAMA-MEA (Mass Manufacture of MEAs Using High Speed Deposition Processes)

Reporting period: 2019-07-01 to 2021-06-30

The MAMA-MEA project set out to address the critical component of a fuel cell, the catalyst coated membrane (CCM) via the development of the additive layer manufacturing (ALM) concept adopting mature deposition technologies from other industries to enable a step-change in production volume.

MAMA-MEA converged to the optimisation and use of slot die and inkjet implemented in an engineering design capable of exceeding the production volume of 1 GW/year of CCMs with an integrated seal, which brings about considerable improvement in materials utilisation and the reduction in use of critical raw materials and scrap, simplifying the manufacturing process, while delivering power density on par with state-of-the-art parts.

The objectives have been addressed as follows:

The identification, evaluation and down select have been performed in reporting period one (RP1) and the assessment of the non selected deposition techniques accompanied by the suggestions regarding their improvement has been performed in RP2.

Power density of 0.8 W/cm2 has been reached. To address the higher degradation rate, more testing is required. Only two batches of additive layer trial (ALT), ALT7 and ALT10, were thoroughly tested, but trials progressed to ALT14.

Engineering design and economic evaluation were done in RP2 for a line capable of 3.1 GW/year as specified in D4.1 but capable of even higher throughput if larger halls are available to accommodate the equipment.

Two full size and one short rainbow stacks were assembled using the ALM CCMs manufactured in the project. One full size stack (ALT7) operated for 2000 h, second stack (ALT10) was not operated due to frost damage to the testing facility. Short rainbow stack with ALT7 and ALT10 tested in house on a test station to compare ALT7 to ALT10.
• WP1 focused on the review and down-selection of the deposition techniques matured in other industries and their modification to be utilized in additive layer manufacturing of catalyst coated membranes. The deposition techniques were assessed and a grading matrix has been defined to down-select the most promising candidate methods. Usage of the deposition methods in the fuel cell context resulted in several issues, such as material incompatibility and foaming, which were addressed in the second reporting period in WP2. Ultimately, the methods deemed not viable for mass manufacturing of fuel cells in short term horizon were further assessed and recommendations were made as to how to improve their performance in a longer time horizon.

• WP2 dealt withscaling up the deposition technique from lab scale tackled in WP1 to fab scale needed for the manufacturing of the CCMs for characterisation in WP3 and the production line engineering concept defined in WP4. Additive layer manufacturing of the entire CCM using inkjet proved not viable in RP2, the manufacturing of the catalyst layers and the reinforced membrane has been done using slot die coating. The inkjet has been developed towards the integrated seal to utilise the inherent flexibility of the method promising considerable improvement in materials utilisation. The assessment of material compatibility of the catalyst layer and ionomer inks continued, but ultimately led to the selection of UV curable inks circumventing the effect of solvents used otherwise. The resulting CCM concept with integrated seal proved effective in testing and simplified the manufacturing process by removing the cutting and attaching the seal.

• WP3 focused on the manufacturing process, taking input from WP1 and WP2 and optimising the parameters to enhance the quality of the resulting CCMs. 14 additive layer trials (ALT) gradually improved various aspects of the layer quality, Pt loading control, number of defects, etc. The findings were used in WP4's engineering design of the MAMA-MEA line and the samples were fed back into WP2 to work out the effect of process parameters on layer quality and electrochemical and mechanical properties, WP3 to preliminarily assess the ALM CCM performance compared to benchmark and WP5 to be more thoroughly assessed at single cell screener, short and full-size stack level.

• WP4 worked out the engineering design of the MAMA-MEA line as well its economical assessment. The specifications and features of the stations comprising the line were defined based on WP3 findings and served for the definition of 3D CAD data using already commercially available hardware where available. The latest version should be able to produce CCMs at the rate of 3.1 GW/year. The life cycle assessment encompassed a projected life cycle of 20 years, estimating the capital and operational expenditure at about 13-18 M€, depending on the scenario.

• WP5 took the CCMs produced in WP3 and performed a battery of tests at the cell level to corroborate the characterisation exercise done by JMFC and the TUC. Additionally, CCMs from ALT7 and ALT10 were selected to be integrated into rainbow fuel cell stacks to provide comparison of the ALMCCMs to the reference CCMs, thus performance, degradation rate and other important parameters were monitored under the same conditions. The ALM CCMs reached performance parity with the benchmark, but the degradation rate was higher than desired, indicating the need for further development.

• WP6 consisted in technical coordination and management ensuring a smooth progression towards project goals. Milestone for WP3, WP4 and WP5 were achieved along with the submission of all remaining project deliverables. The pandemic caused delays necessitating a six-month project extension to avoid sacrificing quality of the submitted deliverables on the account of time. The meetings shifted entirely to the online variety in 2020 and 2021. Along with the general assemblies scheduled every six months, monthly teleconferences and bi-weekly inkjet team meeting were used to monitor and steer the project activities.

• WP7 steered communication, dissemination and exploitation activities to share the project results and findings outside the consortium as well as define the routes of exploitation during the project and after its conclusion. MAMA-MEA consortium informed the funding authority through the Communication plan, EU Survey and TRUST. Two open access papers were published and other two are in the submission or preparation stage and to be published in late 2021 or early 2022.
A combination of slot die and inkjet was selected for the additive layer manufacture of CCMs with an integrated seal directly merged with the electrochemically active layers. Such design reduces waste associated with cutting seals from a sheet and eliminates interfaces between the CCM and the seal, because the seal impregnates the membrane reinforcement spanning the entice unit.

The additive layer manufacturing line throughput estimated at 3.1 GW/year truly enables a step-change in manufacturing volume capable of disrupting the emerging fuel cell market. Moreover, the additive layer manufacturing eliminates some of the bottlenecks plaguing conventional CCM manufacturing roll-2-roll processes that constitute the current state of the art.

The manufacturing technology proved viable for the manufacturing of sealed CCMs for full size fuel cell stacks. JMFC already earmarked the construction of a production facility leveraging the technology developed in MAMA-MEA.
MAMA-MEA workflow in the second period
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