Hydrogen Electrolyzers: Plastic Cell Frames for Industrial Hydrogen Production

Green hydrogen is emerging as a key technology for reducing emissions in industry, energy supply, and mobility. As electrolyzer systems move from pilot plants to industrial-scale production, demand is growing for scalable, reliable, and cost-effective manufacturing processes. One component is coming into particular focus: the electrolyzer cell frame. Engineering plastics and modern injection molding technologies offer promising options for producing these large, dimensionally precise components, which must withstand demanding operating conditions. ENGEL supports this emerging market with machine technology, application expertise, and comprehensive testing capabilities to help industrialize the next generation of hydrogen components.

Electrolyzers use electrical energy to split water into hydrogen and oxygen. Within an electrolyzer stack, the cell frame is an important functional component. It contributes to the stack’s structure, helps guide fluids and provide sealing interfaces, and supports mechanical stability throughout the system’s service life.

Many hydrogen projects are moving from technical feasibility and prototype production to repeatable industrial production. This transition creates new requirements for component design, material selection, and process stability.

Injection molding can play a significant role in this industrialization process. Compared with other manufacturing methods, it offers high reproducibility, design flexibility, and opportunities to integrate functions into a single component. As production volumes increase, it may also provide a cost-effective route to volume production.

For cell frames, however, an existing design cannot simply be transferred to an injection mold. Material selection, component design, mold design, machine technology, and process development need to be considered together from the outset.

Components for electrolyzers operate in demanding environments. Depending on the technology, they may be exposed to elevated temperatures, pressure, water, or alkaline solutions such as potassium hydroxide (KOH). Long-term material performance is therefore a key consideration.

High-performance thermoplastics such as PPS, PSU, PPSU, and PEEK are among the materials being evaluated for electrolyzer components. They can offer combinations of temperature resistance, chemical resistance, mechanical performance, and processability.

Glass fiber reinforcement requires particular attention. Depending on the glass composition and operating conditions, alkaline solutions can attack exposed fibers over time. Fiber content and orientation are therefore important design considerations: if the solution penetrates the component along exposed fibers or interfaces, mechanical performance may decline.

Material selection and component design may help limit this effect, but the extent of any surface damage and its impact on the core must be verified under representative operating conditions. Balancing mechanical performance and long-term chemical stability is one of the key materials challenges in this application.

The appropriate material depends on many factors: electrolyzer technology, component design, operating conditions, service life requirements, cost targets, and validation strategy. ENGEL does not define the material on its own. Rather, ENGEL works with customers, materials specialists, and moldmakers to develop a robust and scalable manufacturing approach.

Several electrolyzer technologies are being developed and deployed for hydrogen production.

PEM—Proton Exchange Membrane Electrolyzers are known for their ability to respond to changing power input and potential for compact system designs. They are particularly relevant when the electricity supply from renewable sources fluctuates.

AEL—Alkaline Electrolyzers are an established technology, particularly for larger industrial applications.

AEM—anion exchange membrane electrolyzers are an emerging field of technology. They combine features of membrane-based and alkaline electrolysis and may enable new stack designs.

Each of these technologies places different demands on components, materials, and manufacturing processes. This diversity creates opportunities to develop application-specific approaches to plastics processing.

Cell frames are more than simple plastic components. Depending on the electrolyzer design, they may be large, flat components with demanding requirements for dimensional accuracy, stability, and consistent production.

Warpage is a key consideration. In large-format components, even small dimensional deviations can affect assembly, sealing performance, and stack performance. Stable processing and precise process control are therefore important.

Advanced processes such as injection compression molding may offer advantages for certain cell-frame designs. By applying compression during molding, the process may help control warpage and achieve the required dimensions in large, flat components.

The appropriate manufacturing process depends on component geometry, material, and performance requirements. Early testing and application-specific development are therefore particularly important.

ENGEL offers customers the opportunity to support development projects through practical testing. In ENGEL’s technical center, customers can work with application engineers to test materials, molds, machine configurations, and process strategies under conditions designed to reflect production requirements.

Using machines with clamping forces of up to 55,000 kN, large-format cell frames can be evaluated under conditions relevant to planned volume production.

These tests help customers assess component behavior, optimize processes, and identify potential development risks. For hydrogen applications, testing can provide evidence to inform decisions about component quality, process consistency, and the next steps toward industrialization. Long-term performance, however, requires appropriate validation beyond production trials.

Together, these activities can help establish a path from concept to volume production.

Producing large cell frames for electrolyzers calls for equipment that can support process stability, precision, and flexibility. ENGEL’s portfolio of large machines provides options for applications in which part size, shot weight, and dimensional stability are critical.

Platen parallelism is an important consideration for large, flat cell frames. Deviations across a large mold can contribute to uneven wall thickness, warpage, or variation in part quality.

The ENGEL duo machine platform offers capabilities for monitoring and controlling platen parallelism. Maintaining the required parallelism during the molding cycle is particularly important for processes that involve a compression stroke.

For large-format cell frames, platen parallelism control works alongside stable plasticization, repeatable injection performance, and process monitoring to support consistent part quality during volume production.

Mold design has a significant impact on cell-frame quality. Gate design, cooling, venting, part handling, and mold stiffness can all affect the finished part.

ENGEL supports customers in developing an integrated manufacturing approach, from machine technology and process development to automation. Depending on the application and production goals, this may include part handling, post-mold cooling, quality inspection, and other automated steps.

ENGEL can also involve experienced moldmaking partners where needed.

As production volumes increase, the focus shifts from making individual parts that meet specifications to maintaining stable, repeatable, and efficient manufacturing over extended production runs. An integrated approach becomes increasingly important at this stage.

Sealing is a key function of an electrolyzer stack. Depending on the stack design, cell frames may require multiple sealing areas around membranes, fluid channels, and the frame perimeter.

Seals may be produced or installed in separate manufacturing or assembly steps. For some applications, integrating or automating these steps could simplify production. Options may include seals applied after molding, automated seal handling, or multi-component designs.

The appropriate approach depends on the specific application and requires validation. Material compatibility, processing temperatures, adhesion, and long-term sealing performance are important considerations.

ENGEL sees functional integration as a promising area for hydrogen-component development, rather than a standard solution for every stack design.

The hydrogen industry continues to evolve. Many companies are developing new stack designs, evaluating materials, and preparing for larger production volumes. At this stage, manufacturing expertise can help turn a feasible design into a repeatable process.ENGEL supports customers with:

• Application engineering

• Machine and process expertise

• Testing capabilities at the ENGEL Technical Center

• Application-specific evaluation of processes involving a compression stroke

• Platen parallelism monitoring and control for suitable large-format applications

• Experience in injection molding of large components

• Automation and system integration

• Support during development and preparation for volume production

For electrolyzer cell frames, the challenge is not simply producing a successful prototype. It is developing a scalable, repeatable, and cost-effective manufacturing approach.

Plastic cell frames may play an important role in future electrolyzer designs. ENGEL can support their development through machine technology, application expertise, and practical testing.

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Engineering plastics may offer benefits such as lower weight, chemical resistance, design flexibility, and opportunities for functional integration. Depending on the cell-frame design and production volume, injection molding may provide a scalable manufacturing approach.

Materials under consideration include PPS, PSU, PPSU, and PEEK. The appropriate grade depends on the electrolyzer technology, operating conditions, component design, and validation requirements.

PEM (proton exchange membrane), AEL (alkaline electrolysis), and AEM (anion exchange membrane) refer to different electrolysis technologies. Each can place different demands on materials, chemical resistance, component design, and manufacturing processes.

For large, flat cell-frame designs, warpage can affect dimensional accuracy and flatness, making assembly and sealing more difficult. Controlling it is therefore an important part of process development.

Injection compression molding combines injection of the molten material with a compression stroke during molding. For some large, flat components, it may help achieve the required dimensions and control warpage. Its suitability depends on the component and process design.

For large, flat cell frames, deviations in platen parallelism can contribute to variations in wall thickness, warpage, and part quality. Maintaining the required parallelism is particularly important in processes involving a compression stroke.

Yes. ENGEL offers application-specific testing at its Technical Center. Working with ENGEL application engineers, customers can evaluate materials, molds, machine configurations, and process strategies under conditions designed to reflect production requirements. The scope of testing depends on the project and available equipment.

Integrated sealing may be possible, depending on the stack design, material combination, and production process. Any proposed solution requires validation for compatibility, sealing performance, and long-term durability.

ENGEL supports customers during feasibility assessment, testing, and process development, and in preparing a manufacturing approach for volume production. The goal is a scalable, repeatable process suited to the application.