Periodic Reporting for period 1 - ASCEND (Advanced Single Cell tEstiNg and Development of HT PEMFCs)
Berichtszeitraum: 2020-07-01 bis 2021-09-30
The core priorities of Horizon 2020 - Work Programme 2018-2020 “Secure, clean and efficient energy” are renewable energy, smart energy systems, energy efficiency, and carbon capture utilization and storage. In-line with these priorities a scalable electric power source is produced by Advent Technologies A/S. The product can be used for applications both off- or on-grid (e.g. critical backup power, temporary or continuous power) and for example can be used for remote telecom stations, range extender in electric vehicles or distributed power generation on board of ships. The system is fuelled with methanol-water mixture, which is first reformed into hydrogen rich gas and then converted into electricity in a high-temperature proton exchange membrane fuel cell (HT PEMFC) stack. This applied research project addressed challenges and issues encountered in the core components of the HT PEMFC stack, namely the processes and physical phenomena inside the membrane electrode assembly (MEA) and its subcomponents. A newly designed test station was assembled and commissioned to test and further improve standard and new (prototype) MEAs (and various subcomponents). Utilising this new test station allowed studying: initial start-up protocol (break-in), optimization of the MEA structure (catalyst coating process, mitigation of acid leaching, comparison of various gas-diffusion layers), and comparison of standard fresh MEAs to used (degraded) MEAs or newly developed prototype MEAs. All the above will continue after the completion of this project and contribute to the optimization and cost reduction of the product (HT PEMFC system), thus creating more efficient, environmentally friendly, and affordable power source.
In the first months the main goal was to commission the test station (single cell tester). This included adding and changing some of the sensors (new, more accurate mass flow controllers needed) and hardware for data transfer and logging (programmable logic controller - PLC), adding electrochemical impedance spectroscopy (EIS), software updates for control and regulation of the test setup (temperature control and test sequence functionality).
Initial measurements were made according to the in-house factory acceptance test (FAT) for full size stacks. Over time the measurements showed that this FAT needs to be changed for the single cell tester therefore it was modified to provide additional data of interest. These changes included:
a) performance testing at various compression pressures on the MEA
b) air and H2 utilisation tests performed at low- and high-current densities
c) addition of EIS
d) logging of data at constant current operation for extended period of time (short term durability tests)
Testing of MEAs was done on two different designs. One is a standard MEA used in the commercial fuel cell systems sold to customers and the other is an experimental one and is made in-house. The two main components of every MEA are:
a) electrodes made of carbon fibre gas-diffusion layer (GDL) which is coated with a catalyst layer (CL) based on platinum particles,
b) the proton exchange membrane (PEM) made of polymer doped with phosphoric acid.
For the standard MEAs these components are supplied by external partners. They are assembled together into a MEA in a German branch of the company located in Achern. On the other hand, the company produces its own in-house developed MEAs with a purpose to achieve the same performance and durability as standard MEAs, while focusing on reduction of costs and environmental impacts. This is a challenging task since changing the material of one component or only changing the composition of a material can introduce significant differences in the performance of the product. There are three major differences between standard and experimental MEAS:
a) In standard MEAs the GDL is made of woven carbon cloth while in experimental a thinner and cheaper non-woven carbon fibres are used
b) The PEM has high acid content which in terms of proton conductivity is good. But the acid also tends to leaches out which blocks the active sites of the catalyst. Therefore, the experimental MEAs are tested at different levels of acid doping to see the effect.
c) The most crucial subcomponent is the CL. In the case of standard MEAs the received GDL is already coated with the CL, while in the in-house MEAs a special roll coating machine is used to coat the catalyst ink onto the GDL. Here the research is mainly focused on:
- Ratio of binders, additives and solvents to achieve proper hydrophobicity, porosity, and thickness of the CL
- Reducing the Pt loading
By introducing the novel experimental setup commissioned within this project research and development and also quality control activities have gained significant boost. The exploitation of the project results can already be seen in:
- Reliable and accurate operation of the test setup
- Capability of faster testing cycles for new MEA components and production processes
- Based on the great success of this project the company decided to invest in additional test setups of this kind to increase its testing capabilities.
The company also collaborates well with the local Aalborg University (AAU), either in joint research projects or supplying materials for research and testing purposes. This collaboration has also contributed to the publication of the scientific article https://doi.org/10.3390/en14112994(öffnet in neuem Fenster) and more are expected.
Initial measurements were made according to the in-house factory acceptance test (FAT) for full size stacks. Over time the measurements showed that this FAT needs to be changed for the single cell tester therefore it was modified to provide additional data of interest. These changes included:
a) performance testing at various compression pressures on the MEA
b) air and H2 utilisation tests performed at low- and high-current densities
c) addition of EIS
d) logging of data at constant current operation for extended period of time (short term durability tests)
Testing of MEAs was done on two different designs. One is a standard MEA used in the commercial fuel cell systems sold to customers and the other is an experimental one and is made in-house. The two main components of every MEA are:
a) electrodes made of carbon fibre gas-diffusion layer (GDL) which is coated with a catalyst layer (CL) based on platinum particles,
b) the proton exchange membrane (PEM) made of polymer doped with phosphoric acid.
For the standard MEAs these components are supplied by external partners. They are assembled together into a MEA in a German branch of the company located in Achern. On the other hand, the company produces its own in-house developed MEAs with a purpose to achieve the same performance and durability as standard MEAs, while focusing on reduction of costs and environmental impacts. This is a challenging task since changing the material of one component or only changing the composition of a material can introduce significant differences in the performance of the product. There are three major differences between standard and experimental MEAS:
a) In standard MEAs the GDL is made of woven carbon cloth while in experimental a thinner and cheaper non-woven carbon fibres are used
b) The PEM has high acid content which in terms of proton conductivity is good. But the acid also tends to leaches out which blocks the active sites of the catalyst. Therefore, the experimental MEAs are tested at different levels of acid doping to see the effect.
c) The most crucial subcomponent is the CL. In the case of standard MEAs the received GDL is already coated with the CL, while in the in-house MEAs a special roll coating machine is used to coat the catalyst ink onto the GDL. Here the research is mainly focused on:
- Ratio of binders, additives and solvents to achieve proper hydrophobicity, porosity, and thickness of the CL
- Reducing the Pt loading
By introducing the novel experimental setup commissioned within this project research and development and also quality control activities have gained significant boost. The exploitation of the project results can already be seen in:
- Reliable and accurate operation of the test setup
- Capability of faster testing cycles for new MEA components and production processes
- Based on the great success of this project the company decided to invest in additional test setups of this kind to increase its testing capabilities.
The company also collaborates well with the local Aalborg University (AAU), either in joint research projects or supplying materials for research and testing purposes. This collaboration has also contributed to the publication of the scientific article https://doi.org/10.3390/en14112994(öffnet in neuem Fenster) and more are expected.
The main goal of the project is to use the developed test setup for quality control of the standard MEAs and especially for novel MEAs developed in-house and also for research activities of current or new components and materials. In literature, life cycle assessment (LCA) analyses have shown that the reduction in Pt catalyst can significantly reduce environmental impacts and reduce the cost of the fuel cell product. Also, using methanol produced by steam reforming of natural gas shows additional environmental benefits compared to traditional backup power sources based on other fossil fuels (i.e. diesel backup generators). The environmental footprint will be further reduced by using the so called green methanol (produced from renewable hydrogen and sequestrated CO2), which is a mature process already at an industrial scale https://www.carbonrecycling.is(öffnet in neuem Fenster). Cheaper components - while achieving better performance through optimisation- will reduce the price per kW of installed power and reduce costs for fuel due to lower consumption (higher efficiency). Lower consumption also improves environmental footprint because less resources are used.
The potential wider societal implications are:
- smart energy system with lower environmental impacts
- reliable and affordable product for backup power
The potential wider societal implications are:
- smart energy system with lower environmental impacts
- reliable and affordable product for backup power