The success of electric cars depends on powerful long-range batteries. Sika has developed novel products that allow more energy to be packed into the batteries.

Electric car drivers do not want to make concessions. The vehicle needs to be fast-accelerating and able to cover a long distance. And when the battery is empty, the time it takes for a coffee break under way should be enough to quickly recharge.

These specifications can be met thanks to modern lithium-ion batteries. Manufacturers are working all out to bundle even higher concentrations of energy into a small space. This presents new challenges for carmakers. “More powerful batteries emit considerably more heat. And this needs to be effectively dissipated to avoid the risk of overheating,” explains David Hofstetter, Senior Scientist with Sika Technology.

Sika development staff testing novel materials for the battery module of the new VW e-Golf

Sika development staff testing novel materials for the battery module of the new VW e-Golf.

Heat-conductive adhesives

Lithium-ion batteries react sensitively to heat. These power packs achieve their maximum electrical output and longest life only at a temperature of between 20 and 30°C. At temperatures above 30°C the battery ages excessively fast, and above 40°C irreversible damage may occur. This can be prevented with cooling elements bonded to the outside of the battery box.

To ensure functioning thermal management, a special adhesive is required. Conventional products have an insulating effect and retain the heat produced by the batteries. The Sika-developed technology based on SikaForce® is different. “Our new adhesive has excellent adhesion and is also thermally conductive,” points out David Hofstetter. This allows the cooling elements to do their job.

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Manufacturers trust Sika

Intelligent thermal management is not the only key factor with electric cars. Electric automobiles require six times more electronic components than conventional vehicles with an internal combustion engine. Besides a motor and a battery, they also need a charger or transformers. For all these parts Sika has the products necessary for heat conductivity, insulation, or encapsulation. Novel grouts can also be used to secure the components and effectively protect them against environmental influences. Sika’s expertise has won over the major carmakers — Audi, BMW, Volkswagen, Chevrolet, Toyota, and Nissan are already relying on these high-tech materials.