Technology platform for high-rate electrolyzer production

The cooperative FRHY project, which forms part of the German flagship hydrogen initiative H2Giga, is aimed at scaling up electrolyzer manufacturing. Increasing electrolyzer production rates requires new technical solutions. To facilitate the development of these essential technologies a model stack was created as a point of reference. Named the FRHY Stack, it is a high-efficiency electrolyzer with the potential for industrial mass production which also supports knowledge and technology transfer.

The ten cells that in total make up the FRHY Stack each consist of two formed and joined plates referred to as bipolar plates or BPPs. These two half plates are initially stamped in a high-speed rolling process on a system newly developed by the Fraunhofer Institute for Machine Tools and Forming Technology IWU. They are then joined together in a welding process that has been adapted to take account of the high processing speed.

FRHY – the reference stack

Another key component is the proton exchange membrane or PEM which belongs to the membrane electrode assembly, otherwise known as the MEA. The membrane is fabricated in a new inkjet printing process devised by Fraunhofer ENAS. The BPP and MEA are embedded into a stiff film framework, the subgasket, to which various seals are added as well as the porous transport layer (PTL), more commonly known as the gas diffusion layer or GDL. The result is a cell design that is suitable for industrial mass manufacturing.

Within the stack, which consists of several cells, the medium and the hydrogen are conveyed through channels on the edge of each cell. Two gold-coated contact plates at the end of the stack supply the stack with energy.

The FRHY reference stack is suitable for a variety of application scenarios and has a high level of efficiency. It is the first time that the model hydrogen factory Referenzfabrik.H2 has made a platform available which will enable a number of sectors and organizations to perform technical and economic assessments of individual components, develop their own business model and position themselves in the supply chain.

Fig. 1: FRHY reference stack, Source: Referenzfabrik.H2

In the initial development phase, a design portfolio was created to define the main parameters for creating cell or stack components and provide a means of contrasting different designs. This allowed two very functional designs to be configured that enable cells to be produced in large numbers. Version M is the type used for the FRHY Stack; its manufacturing potential is based on metal BPPs.

Version K was also developed. This features a newly created intelligent plastic frame that can be made in large numbers in an automated production process. Based on these designs, engineers were able to produce components and bring them together in the FRHY Stack.

As a result of the stack, there is now a valuable frame of reference for the development of the next high-rate generation of electrolyzers. Even electrolyzers in the (price-sensitive) kilowatt range are scarcely marketable without high-rate production processes. If, however, the sale prices are reasonable, a huge market would open up just to meet the energy storage needs of wind farms or residential buildings. What’s more, the stack could be used for application scenarios in the megawatt range. The coupling of stacks would allow plants to produce large quantities of hydrogen, for example in order to supply the manufacturing and raw materials industries.

Direction of FRHY project

FRHY is taking a technology-neutral approach to developing new modules for highly scalable electrolyzer production and to the configuration of digital twins. The objective is to create a portfolio of essential production steps for technical and economic assessment to help industry select the right production processes while considering key parameters, in particular scalability, quality and cost. For instance, production options can be calculated and possible manufacturing strategies can be analyzed, e.g., taking account of automation or integrative continuous process management. This approach not only allows capital costs to be quantified but also return on investment to be deduced in relation to the planned production quantity.

The FRHY methodology also enables production lines to be linked up into one overall value system. This creates transparency and supports the building of supply chains. In addition, it makes it easier to plan factories and make decisions about effective vertical integration.

The unbiased FRHY approach gives an enormous boost to production and testing processes for electrolyzers and ensures a high degree of technology readiness. A key focus here is on furnishing proof of robust and scalable processes. This will additionally benefit the quality and longevity of the product. This is because stable processes also ensure the economic mass production of high-quality electrolyzers and support the further advancement of both production and the product itself.

H2Giga and FRHY

The German education and research ministry is supporting Germany’s entry into the hydrogen economy through its backing of the H2Giga flagship hydrogen project. Over the course of the four-year initiative which runs until March 2025, the project will seek to overcome existing obstacles to the series production of large-scale water electrolyzers. FRHY is a joint project involving six Fraunhofer institutes: IWU, ENAS, IPT, IPA, IMWS and IWES. The decentralized structure means the project is able to incorporate regional partners and networks in Baden-Württemberg, Nordrhein-Westfalen and central Germany.

Potential

FRHY links up physical and virtual solutions and consequently has an enormous impact in terms of innovation on electrolyzer production. This approach has resulted in ambitious plans that will smooth the path toward electrolyzer mass production.

The development of new, configurable production and testing modules for key process steps in stack manufacture will lower production costs by at least 50 percent and improve product quality by 20 percent while also considerably extending the life of complete electrolyzer systems.

The research questions that need to be resolved primarily entail expanding the technological limits of electrolyzer production. Parallel to this, it is expected that the scientific findings will boost the development of a production-optimized next generation of electrolyzers. The FRHY project, and the FRHY Stack especially, have laid the necessary foundations to bring this about.

Digitally mapped production and testing modules are integrated into a technology portfolio for stack production. This toolkit combines the results from physical and digital analyses. For the first time this lets industry deduce urgently needed quantifiable information about output volumes, costs and areas of operation depending on the production method employed.

Opportunities

The FRHY reference stack is the first example of a solution being created to provide a platform for the industrial mass production of electrolyzer components. Deploying continuous roll-to-roll manufacturing technologies is not the only way to increase production volumes. New processes, too, that are consciously designed to make sparing use of critical materials, e.g., platinum, iridium and titanium, as well as in-situ testing technologies bring about a substantial decrease in production costs.

The result is a genuine point of reference and a technological “diamond in the rough” that companies can implement in an industrial setting. The reference stack therefore lays important groundwork for the future availability of hydrogen systems at affordable prices – and ultimately for a hydrogen retail price that is economically viable.

Fig. 2: Rotary stamping of bipolar plates: The structure of the bipolar plate is stamped by a pair of rollers. The main advantage of this method is the high processing speed that leads to a substantial increase in output figures, scaling effects and finally to a significant reduction in cost.

Referenzfabrik.H2

The overall coordination for the FRHY project is undertaken by the model hydrogen factory Referenzfabrik.H2 developed by Fraunhofer IWU. The objective of Referenzfabrik.H2 is to be a pacemaker for the industrial mass production of electrolyzers and fuel cells. The project brings together science and industry as part of a value-creation community that works in collaboration to swiftly ramp up the efficient, scalable production of hydrogen systems.

The factory is underpinned by Fraunhofer IWU’s research and development projects. Solutions that arise from these projects provide the basic structure for manufacturing. This is where industrial corporations are able to contribute their expertise and develop this further together with the participating Fraunhofer institutes and other industrial enterprises. Only through the close cooperation of academia and industry will it be possible to produce high-performance systems for mass deployment more rapidly and at more affordable cost.

Author: Dr. Ulrike Beyer, Referenzfabrik.H2 at Fraunhofer IWU