Innovative Joining Process for Bipolar Plates: SKZ and ZBT Launch Research Project

The SCoPE Project Develops a Novel Approach for Single-Step Welding of Highly Filled Polymer Compounds in Fuel Cell Technology

Bipolar plates have a significant impact on the cost, weight, and power density of fuel cells. As part of the SCoPE project, bipolar half-plates made of highly filled polymer compounds will be manufactured via film extrusion and then embossed. These thin-walled components—with wall thicknesses of less than 0.5 mm—will be joined into functional, fluid-tight bipolar plates using a newly developed welding process as the project progresses.

Development of a Joining Process Without Filler Material
A key focus of the project is to develop and evaluate a fast, single-step—and thus particularly efficient and cost-effective—joining process that does not require filler materials such as adhesives. To this end, existing technologies such as thermal contact welding, thermal pulse welding, and ultrasonic welding will be employed; the welding process with the highest application potential will be identified, and its process parameters will be specifically optimized to meet the special requirements of highly filled materials.

Improvement of electrical and thermal conductivity at the joints
In particular, the project aims to develop solutions to overcome the challenges posed by high filler content—such as carbon black and graphite. The goal is to significantly improve the mechanical and chemical stability of the joints as well as the electrical and thermal conductivity at the joint locations. Furthermore, the plan is to validate the developed approaches using an industry-relevant demonstrator.

“With SCoPE, we aim to develop a robust and cost-effective joining process that makes it easier for SMEs in particular to enter the mass production of bipolar plates,” explains Dr. Lisa Stiegler, Senior Scientist at SKZ in the Thermal Joining Group. “In doing so, we want to lay the foundation for broader industrial implementation of fuel cell technology.”

Further Development of Hydrogen Technology
In addition to SKZ’s joining expertise, ZBT is contributing its expertise in compound development, extrusion, and stack testing to the project. A project committee comprising companies across the entire value chain is providing additional support for the development.
SCoPE aims to lay important groundwork for further advancing hydrogen technology and tapping into new market potential for plastics processing and mechanical engineering.