What do the trends toward electric mobility and autonomous driving mean to Freudenberg Sealing Technologies (FST)? What about the transformation in energy technology? What components will be needed in these markets in the future? Which of FST’s core competencies can be applied in these areas? What applications are coming under consideration? How must new parts and modules be designed to offer customers added value and give FST unique selling propositions? Technology & Innovation (T&I) is tackling these issues proactively. Many different innovations have already emerged from its work – or are in the process of development. Jens Trabert, Vice President, T&I, Innovation Commercialization, offers some examples.
“We anticipate future trends systematically and try to actively develop components in line with them wherever we can build on existing knowledge, and they are good strategic fit for us. We increasingly find ourselves on a path, taking us from the individual seal to complete modules. We are working to acquire the necessary design and production expertise for this.”
Jens Trabert | Lead Function, Technology & Innovation at FST
The Centerpiece: A Safe Battery
The lithium ion batteries are the centerpiece of electric vehicles and e-mobility. Cells are the smallest units of these energy storage systems. When there is a short circuit, energy is abruptly released as heat and pressure. The electrolyte turns into gas and the cell ruptures. This can trigger a disastrous chain reaction from cell to cell and cause a fire that spreads through the entire battery. FST has developed solutions that prevent this uncontrolled cell-to-cell spillover – or at least slow the process long enough for occupants to escape the vehicle.
Heatshields …
… from FST create barriers between the individual cells. “We are now developing the second generation of our heatshields. These are extremely compact, elastic mats made of a mix of materials in a multi-element structure. This makes it possible for the heatshield to withstand higher temperatures for a significantly longer period of time. Here our material expertise and our “Innovating Together” with Freudenberg Performance Materials have come into play,” Trabert said.
Thermal barriers …
… perform the same tasks as heatshields, only at another point in the battery housing. These three-dimensional profiles prevent flames around the heatshields from spreading across the upper ends of the cells. FST manufactures these 3D thermal barriers with an injection-molding process using a special silicone-based material developed in-house. In parallel, FST is developing new materials for flat, two-dimensional thermal barriers, that is, sheet products that can be used as flame protection around the battery housing.
DIAvent …
… is the name of FST’s patented pressure equalization element that combines two functions in a single part. In normal operation, it enables an electric-car battery to “breathe.” The technical term is “bidirectional pressure equalization.” It also draws off the overpressure that occurs quickly during thermal runaway – thanks to its high degassing rate. There are also different versions of the innovation. During emergency degassing, the flow rate of the HighFlow model is four times as high as that of the standard version. DIAvent Light only provides pressure equalization during normal operation. Other variations are conceivable, potentially for battery-powered two-wheeled vehicles.
Busbars …
… are power rails. In lithium ion batteries, electricity flows from cell to cell through power rails made of copper, not wires or cables. They also require the maximum protection against flames, whether they are straight, meter-long rails, wound molded parts or threaded elements. Busbars are either coated with flame-retarding, electrically insulating materials or encased in elastomers to prevent the short-circuits and fires that can result from overheating. The jobs of coating and encasing metals fall squarely into FST’s core expertise. “It is obvious, even if it often requires explanation, why Freudenberg is offering products such as busbars. But as we collaborate with customers, we realize again and again how much our experience and our development expertise are in demand in these new businesses, which are still marked by uncertainty,” Trabert said.
Prismatic Cell Caps: Puttng A Lid On It
Cell caps play an important role in power transmission in lithium ion batteries. They are also a safety measure preventing cell chemicals and vapors from reaching the environment, sealing the two poles of the cell and insulating them from one another. The caps contain a range of parts. “Years ago, we developed media-resistant sealing materials that “can live” with cell chemicals. Since we also understand metal processing, whether for Simmerrings® or valve stem cells, it made sense to manufacture and offer the entire cell. The major advantage to the customer: They don’t need to assemble individual parts from the anode to the integrated rupture element on their own. We provide them with the total module as a finished assembly,” Trabert said.
EMI Shielding: Teaching Plastic To Shield
Consider sensor, camera and radar systems: These electronic vehicle components give off electromagnetic radiation and can disrupt one another. The technical term is electromagnetic interference, or EMI. That means they must be shielded from one another, either with housings made of a conductive metal, usually aluminum, that is comparatively expensive and heavy, or with housings made of plastic, on which a seal can be directly injection-molded to permanently attach it.
For EMI shielding, however, the plastic must be made electrically conductive. FST has developed several ways to do this. One is known as “EMI coating,” the application of a conductive coating onto the surface of the plastic part. FST is working with BASF to optimize the process.
eCON: Seals With A “Built-In Lightning Rod”
With a systematic process, FST is taking its sealing expertise to a new level for electric powertrains. Its eCON products are an example. These low-friction radial shaft seals have a “built-in lightning rod,” or integrated grounding. The multifunctional seals dissipate harmful currents in the engine mount, preventing bearing damage that electric erosion can cause.
Electrolyzers: Hydrogen For Fuel Cells
“Our goal is to participate in a megatrend: the use of hydrogen as a future energy source,” Trabert said. Electrolyzers uses electrical energy to produce hydrogen. They function much like a fuel cell – but in reverse. Like those in fuel cells, electrolyzer stacks have to be sealed. FST already provides flat seals and O-rings that are resistant to electrochemical media. “The major challenge with electrolyzers and fuel cells is reducing costs with automated production. Our concept is to connect our seals directly to the frame or the bipolar plate with an automated process as part of the vertical integration of our seals, and then deliver the unit to the customer as a finished module. This saves the customer several production steps,” Trabert said.
Innovative Materials And Processes
Product innovations often go hand-in-hand with material and process innovations – or even presume they can be made available. That was the case with thermal interface materials (TIM). FST has had a thermally conductive and electrically insulating silicone material in its product line for a few years. FST now has developed it further – in two ways. First of all, the material can now also be processed into complex three-dimensional geometries using injection molding – an entirely new approach. Secondly, the material can become an integral element of two-component parts. It can be directly sprayed on, and it adheres to plastic, aluminum or copper. A two-component part with a thermoplastic main body has been in series production for some time for charging ports on electric cars. Its specific contribution is to make charging vehicles safer and more efficient: FST’s product “feeds” sensors with thermal information. The charging process can be continually monitored and controlled on this basis.
