eCool Solutions

Multilayer cooling technology for EV battery applications

Keeping batteries cool is a top priority in electric vehicle systems. If a battery system overheats, it not only affects the battery’s range and longevity, but it can cause thermal runaway and become a major fire and safety risk. The latest technique to keep multiple battery cells cooled to the optimal temperature, simply involves submerging the cells in a dielectric fluid that flows around the system carrying heat away from the cells. This system works in the same was as coolant flowing around a petrol or diesel combustion engine, with a similar pump to push the coolant around the battery module system via a network of flexible thermoplastic tubes and rigid polymer pipe connectors.

Thermoplastics and elastomers have long been important in automotive cooling lines, not only because they resist cooling fluids, but they also defy hydrolysis and zinc chloride degradation, and stress cracking. The increased requirements for cooling in electric vehicles compared to combustion engine vehicles means that cooling lines themselves can be 300% longer.

Sustainable, cost-effective and high-performance solutions are in demand. eCool multilayer technology meet these demands.

eCool multilayer technology consists of Zytel® LCPA as the outer layer, a tie layer as the intermediary and a TPE / elastomer (such as Sarlink® from Teknor Apex) as the internal layer. This innovative approach provides a wealth of advantages over traditional technologies, including:

• Design flexibility – multilayer tubes can be extruded smooth or corrugated, with customised thermoplastic elastomer placement for desired flexibility
• Material combined can withstand the extreme environmental temperature range of -40°C to over 150°C
• Lightweight alternative to traditional rubber solutions
• Sustainability - most conventional cooling lines are made from PA12. e-Cool technology excels in reducing global warming potential compared to PA12. See the chart below comparing a mono-layer coolant tube variant alongside a multi-layer construction using a conventional TPO for the inner layer

Zytel® LCPA (the outer layer material) is well recognised for its suitability and compliance with automotive OEM specifications. These long chain polyamides are proven performers, providing benefits such as:

• Hydrolysis-resistance to transmission fluid, water-glycol, and dielectric fluids
• Electronic and electrically friendly solutions to prevent metal corrosion and pollution of coolant fluids
• Elevated mechanical properties at low and high temperatures
• Resistance to thermal shock and impact for extended component life
• Laser welding grades
• Laser marking capability for easy part traceability

Sarlink® from Teknor Apex, an ideal material solution for the internal layer in the eCool system, exhibits a range of excellent properties including excellent elastic properties, chemical and fluid resistance and improved long term performance over EPDM due to better heat aging properties. Sarlink® is the premier choice for flexible automotive parts requiring long-term performance.

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