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Solid Oxide Stack Lean Manufacturing

Periodic Reporting for period 2 - SOSLeM (Solid Oxide Stack Lean Manufacturing)

Período documentado: 2017-10-01 hasta 2019-03-31

Fuel cells convert the chemical energy stored in a fuel, e.g. hydrogen into electricity. They are one of the most effective technologies for energy conversion known so far and have the potential to significantly contribute to future decentralised electric power grids with a variety of technical advantages. In particular, stationary fuel cells will be able to reduce carbon dioxide emissions as well as dependencies on fossil fuels and may also help to compensate efficiently load variations in the power grid caused by fluctuating renewable energy generation, e.g. from solar or wind energy sources. However, market penetration of fuel cells is hampered by comparably high production costs. SOSLeM set out to tackle this problem by improving production processes as well as developing and applying novel manufacturing technologies for fuel cell stacks.

The SOSLeM project aimed at reducing manufacturing costs for fuel cell stacks while at the same time making production more resource efficient and realising environmental benefits. Specifically, the project objectives were to:

• Develop new and optimised processes for the production of the fuel cell cassettes by (i) avoiding cassette surface pre-treatment; (ii) implementation of automated laser welding for the preparation of the cassettes and the anode contact layer taking into account lean manufacturing rationales.
• Improve stack preparation by (i) advanced sealant curing and stack conditioning; and (ii) improved end-of-line stack characterisation, integrated in a newly developed stack conditioning test bench.
• Obtain environmental benefits by (i) on-site nickel removal from waste water; (ii) using protective coatings with less environmental impact, and (iii) hot gas cleaning.
• Reduce production time and costs and improve production flexibility by (i) using a large furnace arrangement; (ii) introduction of a multi-stack production station; (iii) cosintering or protective coatings.

Overall, a reduction of manufacturing costs of about 70% were targeted.
The work performed during the SOSLeM project has led to the following main results:

• The project partners have developed new and optimised already existing processes for the production of the fuel cell cassettes by lean manufacturing processes, improving the sealing adhesion on the cassettes, and automation of the laser welding process.
• The production time and costs have been reduced and flexibility has been increased by large furnace arrangement and introduction of a multi-stack production station.
• The new developed cassette design has reduced the cassette welding time from 540 seconds to 50 seconds.
• The stack preparation has been improved by advanced sealant curing and stack conditioning, resulting in faster commissioning (time reduced by about 40%) and 35% reduced gas consumption while maintaining high yields.
• Environmental benefits have been realised by the implementation of improved protective coatings for the steel in the fuel cell stack.

The improvements have summed up to a reduction of stack manufacturing costs by about 60%. Together with other improvements made outside of SOSLeM the capital costs could be decreased to about 3,700 €/kW.

An improved waste water cleaning unit was finally not integrated in the existing production line, as the investment costs led to too long payback periods. It is, however, now under reconsideration for the soon to realise new production plant where due to upscaled production rates higher amounts of waste water are anticipated. It further followed that the developed filter to clean the exhaust gas was too bulky to be implemented in the existing system design, and that the developed routines for performing advanced characterisation of the stacks in the end-of-line testing need further refinements. Considerable progress has nevertheless been realised, and thus the results provide a solid basis for future research.

The research performed in SOSLeM has resulted in two PhD theses and was also disseminated to scientific audiences in two peer-reviewed publications. Further articles are expected to be published.
SOSLeM results were also disseminated in a number of conferences and trade fairs (see for details). Moreover, two patents were filed as an outcome of the research carried out.
The SOSLeM project focused on the simplification of SOFC manufacturing steps and on the evolution of quality control systems for stack components in a real production line and at the final stack conditioning and validation, with the ultimate aim of a drastic reduction in production costs, stabilisation of the process, and increased product reliability.
From a strategical point of view, the impact of SOSLeM has quantum-leap potential for European SOFC manufacturing and market penetration, when considering Europe’s present situation compared to its competitors in other regions. Europe has large internal markets, into which non-European fuel cell suppliers have been trying to enter. In SOSLeM, the consistent drive for leaner fabrication has resulted in a reduction in manufacturing steps and time and a reduction of materials cost by the Co/Cu replacement. In summary, the resulting overall stack cost reduction is believed to give SOLIDpower an edge over other competitors. It was a key factor contributing to the new production plant currently under construction in Italy by SOLIDpower which will increase production capacity to 25MW/y initially and potentially up to 50MW/y, creating many new high quality employment opportunities. This is also true for suppliers of SOLIDpower, such as SOSLeM beneficiaries Athena or Greenlight who will be able to significantly increase their sales towards SOLIDpower. Greenlight will also be able to market their upgraded stack qualification stations to other manufacturers.
AVL plans to commercialise the generated know-how on the new stack characterisation methods by marketing of new end-of-line test equipment that can currently be purchased on a commercial basis in the frame of joint projects.
Rendering of new SOLIDpower factory (front view)
Rendering of new SOLIDpower factory (top view)
SOSLeM consortium map