Use of fluoropolymers inside fuel cell systems

Based on their properties, fluoropolymers are often an optimal choice leading to longer life time and higher efficiency of the system.

In the GDL (Gas Diffusion Layers), thin carbon fiber and paper layers are often coated with fluoropolymers. This coating protects the carbon fibers from soaking water and as a result, protects the full membrane from being damaged when pressurized.

In MEA (membrane electrode assembly) stack, there are usually two major kind of gaskets. The “sub-gasket” holds the CCM (catalyst coated membrane) in place whereas the “frame gasket” (or “main gasket”) mainly seals the stack towards the bi-polar plates against leakage and often is also used to protect the GDL from being damaged by over compression. With high temperature and excellent chemical resistance, fluoropolymers are proven to be a suitable choice for both types of gaskets.

Lastly, motors for electric vehicles involve exposure to Automatic Transmission Fluids (ATF) and must offer compatibility to these fluids.

Advantages offered by fluoropolymer films in EV Motors

The addition of fluoropolymer films to slot liner and phase insulation constructions (aramid paper and polyimide) is crucial to meet the rigorous demands in motors for electrical vehicles and long-term reliability requirements.

Most typically, fluoropolymers are used inside a fuel cell as a polymer membrane itself. Very often this would be a thin film of sulphonated PTFE is used as part of an electrolyte layer in the heart of each cell only allowing protons to transfer through this membrane.

Fluoropolymers as processing aids for fuel cells components

All the above mentioned fluoropolymers (films, laminates and coatings) will remain inside the final product/stack. But there is also a wide range of uses for fluoropolymers as processing aids in the manufacture of the sub-components to be used inside the fuel cell.

One typical example is the catalyst coated membrane (CCM). The CCM itself contains the membrane separating electrons and protons from the hydrogen molecules and is often made of sulphonated PTFE film. There are different ways to apply the catalyst layer. One is the decal transfer method in which the liquid catalyst will be applied to a substrate, homogeneously spread, dried and transferred to the membrane - thus forming the CCM. For this a PTFE-composite or film release carrier material can be used. It is critical to have low levels of defect in order to achieve high yields and produce thinner CCM layers which are increasingly being demanded by customers especially the automotive market Therefore, a smooth and homogeneous surface is a must here.

Other uses of fluoropolymers in fuel cell systems and hydrogen electrolysers

In addition to the above, a lot of tubes, hoses and plugs made of PTFE and other fluoropolymers are in use inside and on the exterior of fuel cells and electrolysers.

Interested in polymer membranes and processing aids for fuel cells?

Fuel cells and electrolysers are considered to be a major contributor to supplying the world with sustainable energy in the future and fluoropolymer based solutions will play a major role in supporting this change by either simply enabling the performance of these units as well as increasing the efficiency and decreasing the power losses during operational periods.

• PTFE Fabrics for Fuel Cells
• PTFE Fabrics Processing Aids for Decal Process

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