Adhesive tapes for MEA production

During operation, it is important to reliably separate the media used, for example oxygen and hydrogen in the PEM fuel cell. Reduced performance or even complete failure of the stack would be possible consequences of a leak.

However, operational reliability is not only important at the smallest level, the individual cell. To be competitive, fast and reliable production processes are also required.

CMC Klebetechnik offers solutions for both areas - operational reliability and high production speed:

Sealing and stabilizing the MEA

Subgasket seals are used to mechanically stabilize the MEA outside the active area. CMC 61145 is a laminate adhesive tape specified for this application. It consists of a thin Kaladex® or Teonex® PEN film coated with a hydrolysis-stable special PSA adhesive. The pressure-sensitive adhesive does not "poison" the catalytic converter coating or increase the conductivity of the cooling medium. The advantage of the permanently elastic adhesive is its long-term function as a seal (subgasket) between the membrane (e.g. Nafion®) and the frame formed by the film. The frame stabilizes the thin membrane film and makes installation much easier. Compared to other sealing concepts, the main advantage of CMC 61145 is its extremely low thickness (length of the stack), high pressure resistance and simple process control during manufacture.

The standard film has a thickness of 25µm, but 50µm and 100µm film thicknesses are also available on request. Other polymers for higher hydrolytic stability are also possible, e.g. PPS, PFA, PPSU, PEEK.

As CMC Klebetechnik itself is the manufacturer of the product, the required layer thickness of the adhesive can also be adapted to the thickness of the electrodes (GDL, MPL, CCM).

Production aid for the roll-to-roll process

The production of MEA units using the roll-to-roll process is a good way to manufacture as quickly and cost-effectively as possible. This continuous production process has been used for a long time in label production, for example. The packaging industry is also very familiar with the roll-to-roll process, as it is often important to be able to produce large quantities of packaging quickly and cost-effectively.

The initially stable PEN film from CMC 61145 becomes very unstable when the media passages and the central opening for the membrane are cutted out. It is almost impossible to guide the Subgasket adhesive tape through a lamination process with a precise fit in this unstable state.

A special adhesive tape from CMC-Klebetechnik can help here: CMC 12089. This relatively thick polyester adhesive tape (also available in 50µm) can be laminated with the PEN film before the die-cutting process. As the CMC 12089 adhesive tape is not die-cutted through during the subsequent die-cutting process (kiss-cut), it remains as a stable carrier for the subsequent roll-to-roll process. This enables precise lamination between the two CMC 61145 sub-gasket films and the inner membrane. The relatively thick polyester stabilizing film is not stretched by the tensile forces even in a hot lamination process.

After the lamination step, the CMC 12089 adhesive tape can be removed from the bond without leaving any residue and with minimal effort thanks to the special adhesive.

With the CMC 12089 laminating aid film, it is possible for automation specialists to switch from the comparatively slow process of "stacking" individual parts to the considerably faster process of roll-to-roll laminating. This is because it is now possible to master the high precision requirements and control the web tension at high speeds.