Some suppliers of battery cooling Baknor www.baknorthermal.com Boyd Corp www.boydcorp.com Castrol www.castrol.com Dober www.dober.com DuPont www.dupont.com Grayson Thermal Systems www.graysonts.com Kautex Textron www.kautex.com Miba www.miba.com Ricardo www.ricardo.com Siemens Digital Industries Software www.sw.siemens.com TLX Technologies www.tlxtech.com Valeo www.valeo.com Voss Automotive www.voss.net Webasto www.webasto.com 70 September/October 2025 | E-Mobility Engineering Maintaining energy density Every gram and cubic centimetre dedicated to cooling represents lost potential for energy storage, making thermal system compactness crucial for maximising battery pack energy density. Modern cooling approaches typically reduce gravimetric energy density (unit: Wh/kg) by 5–10% and volumetric density (unit: Wh/L) by 6–10%, although advanced designs can mitigate these impacts significantly. The most effective strategies focus on eliminating non-functional mass and volume. Conformal cooling systems that integrate directly with cell geometries avoid the empty space inherent in traditional cooling plate arrangements. Some designs incorporate cooling channels into cell casings themselves, achieving thermal transfer without any separate cooling component volume. Material selection plays an equally important role, with composite materials and thin-wall metals reducing structural mass while maintaining performance. Developing immersion cooling approaches may fundamentally change the energy density equation. By eliminating inter-cell spacing materials and leveraging the coolant itself as both thermal transfer medium and electrical insulator, these systems can achieve packaging factors approaching 90% – a significant improvement over conventional designs. Tough duty Off-highway EVs and industrial applications present unique thermal management challenges that go beyond typical automotive requirements. The combination of dust, water, vibration and extreme swings of temperature demands robust cooling solutions with enhanced protection features. Modern systems address these challenges through multiple layers of protection, beginning with sealed enclosures rated to IP67 or higher standards that prevent particulate and moisture ingress. The most advanced implementations employ specialised hydrophobic coatings on critical components to repel water and prevent corrosion, while highefficiency particulate filters maintain cooling performance in dusty conditions. Some designs incorporate self-cleaning mechanisms using periodic reverse airflow pulses to clear accumulated debris from heat exchangers. Again, material selection plays a crucial role, with corrosion-resistant aluminium alloys and polymer composites replacing conventional materials in harsh environments. It’s just a phase PCMs continue to attract research interest for their potential to smooth thermal transients and reduce peak cooling loads. Current exploration focuses on two primary categories: paraffin-based organic PCMs offering high latent heat capacity (150 J/g), and advanced bio-derived materials. However, the limited temperature operating range of PCMs presents a fundamental challenge. These materials provide their full thermal benefit only during phase transition, becoming much less effective once fully melted or vaporised. This narrow window of operation requires precise system tuning to match the expected thermal load profile. Weight efficiency remains another concern because the mass of PCM required to meaningfully impact battery temperatures often offsets the energy density gains. Two-phase cooling systems using specialised refrigerants show more immediate potential for high-heat-flux applications. Modern low-globalwarming-potential fluids like R1234yf can handle heat fluxes of 5–10 W/cm² while maintaining stable performance across wide temperature ranges. However, these systems introduce their own complexities, including potential material compatibility issues and the need for robust containment systems to handle pressure variations. Furthermore, maintaining temperature uniformity in two-phase systems is challenging as the transformed fluid no longer transfers heat. Product focus | Battery cooling Kautex’s cell-to-pack demonstrator shows a structural cell holder, integrated emergency venting, two-phase immersion cooling and flexible foil cooler options for its Pentatonic battery packs (Image courtesy of the author)
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