Future-proof Series Production For Fuel Cells

2023 Author : Hannah Pearcy | [email protected] . Last modified: 2023-05-24 11:12

Fuel cells are an ideal addition to batteries in electric drives in order to achieve long ranges. However, relatively few vehicle models with this drive technology are still available on the market in Germany. The reason: producing fuel cells is expensive . The researchers at the Fraunhofer Institute for Machine Tools and Forming Technology IWU are working on a more cost-effective solution

They think holistically and consider all components of the fuel cell drive. "It starts with the supply of hydrogen , affects the selection of materials that are directly involved in the generation of electricity in fuel cells, and extends to heat regulation in the cell itself and in the vehicle," explains Dipl.-Ing. Sören Scheffler, project manager at Fraunhofer IWU in Chemnitz.

Racing car Silberhummel demonstrates technology

The researchers illustrate this research approach with the technology demonstrator "Silberhummel " at this year's Hannover Messe. The Silberhummel is based on a racing car developed by Auto Union in the 1940s.

The history of the silver bumblebee

As early as 1939/1940, the racing sports car was designed in the central design department of the Auto Union in Chemnitz. However, the sports department was closed in these war years and had to give way to the increased armaments production. The design of the racing car disappeared into a drawing roll.

The idea of the racing car was revived by the author Frieder Bach. He knew the designer at the time and thus got hold of the archived drawings. The design of the body corresponds to the then ideal of beauty and the vehicle construction guidelines of a streamlined body.

Replace graphite bipolar plates with thin metal foils

In a first step, the researchers concentrate on the heart of the fuel cell , the so-called stack. In this component, electricity is generated in many cells stacked one on top of the other, which consist of bipolar plates and electrolyte membranes. The researchers are researching how they can replace conventional graphite bipolar plates with thin metal foils . “This makes it possible to produce stacks quickly and cheaply in large series. This significantly increases productivity,”says Scheffler.

The focus is also on quality assurance. Every component for stacks is checked directly during production. This is to ensure that only 100% tested parts find their way into stacks .

Silver bumblebee as a technology demonstrator

The scientists at Fraunhofer IWU are now creating the silver bumblebee step by step as a technology demonstrator. In doing so, they are pursuing two strategies: First, that industrial automobile production in quantities of 1 is economically possible . Using suitable forming technologies and processes such as incremental sheet metal forming, punching-bending-joining, adaptive manufacturing or deep drawing, the scientists show that it is possible to work quickly and cost-effectively.

The second strategy approach is an electric drive based on a hydrogen fuel cell to accomplish. This makes the silver bumblebee a showcase and test stand for the Saxon fuel cell cluster Hzwo. The aim of the cluster is to establish an innovation and value creation network around the topics of fuel cells and green hydrogen in Saxony. In three to five years, the demonstrator should be able to drive itself using these technologies and the "Made in Saxony" products.

Make stacks adaptable to the environment

At the same time, the Fraunhofer IWU is pursuing the goal of improving the adaptability of the stack to the environment and the driving situation. Scheffler: “Our assumption is: In order to save hydrogen, a dynamic adjustment to the environmental variables - also with AI support - can help. It makes a difference whether a drive is used when the outside temperature is high or low, or whether it is used in the lowlands or in the mountains. So far, stacks have worked in a predefined, rigid operating area that does not allow this environment-dependent optimization.”