How adhesives determine the success of Tesla and VW

One of these high-tech adhesives is called Loctite TLB 9300 APS, developed by Henkel. It can be found in new electric cars that have been rolling off the assembly line since the beginning of the month. Henkel does not want to name the car manufacturer with reference to the trade secret.

One thing is clear: the stickers of the Dax group are used by all major car manufacturers such as VW or Tesla, by suppliers such as Continental or Bosch and by battery manufacturers. The Henkel experts work directly in the car companies’ factories to develop suitable adhesives.

Adhesives are a key component of electric cars

The traditional Düsseldorf group is known to the public for its Persil detergent. In fact, the company generates almost half of its sales at around ten billion euros and almost 60 percent of its profit at around 1.6 billion euros with adhesives. “E-mobility is extremely important for Henkel,” says George Kazantzis, who has global responsibility for Henkel’s automotive components business. “We can help automakers find their way in the industry revolution.”

Adhesives are a future market, especially in the automotive sector. The growth is due to the fact that more and more electric vehicles will be driving on the roads in the future. Car expert Stefan Bratzel expects that more than three million electric cars will be newly registered in Germany in 2030 – ten times as many as last year.

Adhesives were already used extensively in combustion engines because they are cheaper and lighter than screws, for example. Adhesives and coatings are becoming even more important for e-cars. Because the battery cells have to be fixed. And special coatings prevent a battery fire from spreading too quickly. These can even increase the performance of the battery itself.

“Adhesives are an integral part of the mobility revolution and a value driver for manufacturers,” says Christian Faitz, analyst and chemical expert at Kepler Cheuvreux. The stock analyst puts the global market for adhesives in the electric car sector at four billion euros by the end of the decade – four times as high as now.

The Hamburg-based adhesives manufacturer Tesa also sees e-mobility as the “fastest growing market, on which we are putting a strong focus on development”. The US competitor Dupont speaks of “strong market potential” by making batteries safer and more durable and increasing their range. Parker Lord even sees “enormous growth”. Both US companies are increasing their production capacities worldwide with investments worth millions in order to meet the demands of car manufacturers.

Henkel sees 2.5 times as much potential in e-cars as with combustion engines

The competition is fierce, but Henkel is the world’s largest adhesives manufacturer with a market share of around 17 percent. Around 200 scientists, including 50 battery experts, are researching around 20 areas of application for adhesives in electric cars. It is estimated that Henkel invested more than 150 million euros in research and development in this area in 2021 alone.

That should pay off: The Dax group expects a market potential of up to 250 euros for an e-car. It is only 100 euros for a combustion engine. Henkel has been supplying the automotive industry for decades, for example with adhesives to seal the engine block or coatings to protect the car from rusting.

Henkel explains that the potential for electric vehicles is 2.5 times as high, primarily due to the need for thermally conductive adhesives. The group made a breakthrough in this area in 2019 with the “gap filler”. The adhesive is applied between the housing of the battery cells and the cooling plate, conducting the heat out of the battery. The gap between these two components must be closed because air does not transport heat as quickly – hence the name “gap filler”.

What sounds trivial is innovative. Because the adhesive has to be applied within a minute in order not to slow down the high cycle times in car production. However, the gap filler consists of 90 percent solid materials such as the smallest ceramic particles. This is what makes heat conduction possible.

Henkel manager Stefan Kreiling, who is responsible for product development in the automotive sector, knows how difficult that is. He uses the comparison to rice pudding: “If you have 90 grams of rice grains and ten grams of milk, it is difficult to apply the mixture in a pasty, quick and precise manner.” The Henkel experts managed this by selecting special grain sizes and the surfaces of the Treated fillers so that they can flow better.

Like an iPhone – only much bigger

Henkel can draw on innovations and experience that the company has gained with all major smartphone manufacturers such as Apple and Samsung. Here, too, adhesives ensure that the device electronics do not overheat. With mobile phones, however, the adhesives are required in microscopically small quantities. In car production, it’s about three liters that have to be filled up quickly despite the large volume.

In addition, the adhesive producers had to adapt their special smartphone solutions for the automotive industry and make them cheaper, explains Holger Fricke, adhesives expert at the Fraunhofer Institute for Manufacturing Technology and Applied Materials Research IFAM. “In the electronics sector, there are often silver particles in the adhesives. In the large quantities that are required for cars, that would have been far too expensive and would not have found any buyers.”

Henkel solves these problems with the Loctite TLB 9300 APS. This adhesive marks the successor technology to the “gap filler”. While the first innovation was mainly used for heat conduction, the new generation also has to be adhesive, because the battery cells are now individually glued to the cooling plate.

The challenge: The ceramic fillers required for heat conduction make the adhesive brittle and it can break easily. Thanks to their decades of experience, the Henkel experts were able to make the adhesive so elastic that it does not break despite the particles. To do this, the team tested various formulas in the in-house laboratories for months until the special solution met the requirements. Henkel’s competitor Parker Lord has also recently been selling a comparable solution.

Faster innovations needed

Adhesive producers have to deliver such innovations faster and faster. “The speed of new developments in the automotive environment has increased tremendously,” observes adhesives expert Fricke. Political pressure, new regulations and increasing demand for electric vehicles are forcing car manufacturers to make improvements at ever shorter intervals. Europe’s largest car manufacturer puts it this way: “Volkswagen is constantly working on further innovations in development with proven adhesive experts.”

Adhesive manufacturers take on a new meaning in car production, which is changing more fundamentally than ever in its history. In the past, the car manufacturers would have made specifications and Henkel sometimes had more than a year to develop solutions, reports Manager Kreiling, who has been working in the car sector for 15 years. “We now have a completely different way of working together, almost on an equal footing.”

The Henkel employees at the local car manufacturers are involved in the development right from the start and look for solutions in several iteration loops. The problems often only become apparent in the course of car development – ​​and then answers are needed quickly.

Henkel has succeeded in doing this, for example, with a new flame-retardant coating that was developed in just six months. This was made necessary by regulatory requirements: if the battery catches fire, the fire must remain in the battery box for five minutes in future so that the occupants have enough time to get out of the car. Henkel’s coating is applied to the battery cover, withstands temperatures of up to 1000 degrees – and retards the flames. Competitor Tesa recently launched adhesive tapes that offer similar functions.

New innovation center

In order to be able to keep up with the new speed, Henkel is inaugurating a new innovation building this Monday at the main plant in Düsseldorf. It is hoped that 650 employees will work together more innovatively there on an area the size of almost seven football pitches. Henkel paid 130 million euros for the building.

All measurement data should be available there in digital form, tests should be automated and the exchange between car manufacturers, research and Henkel should be easier. The center is the link between Henkel research and the employees in the car companies. “The center is the key to making our innovations faster,” says Stephan Höfer, who is responsible for the global market strategy for e-mobility at Henkel.

Such centers are also gaining in importance in the face of competition, because many questions are still unanswered. Switching to electric cars also requires innovations in whole new areas. Because the road noise is louder in the quieter Stromer, Henkel recently developed a technology to make the rolling noise quieter. The Düsseldorf-based company glues acoustically effective materials inside the tire, which dampens the sound.

This shows that adhesives will continue to be important in the automotive industry for a long time to come – and make further innovations necessary.

More: “Conductive charging” – Easelink wants to make the charging cable for electric cars superfluous