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Thermally conductive plastics are showing significant potential for use in thermal management of charging systems for electric vehicles. One recent example is the charge controller in the fully electric vehicle of a sports car manufacturer based in southern Germany. This controller contains a cooling element made of the thermally conductive and electrically insulating nylon 6 Durethan BTC965FM30 from Lanxess which dissipates the heat generated in the plug contacts of the controller when charging the batteries. Aside from preventing the charge controller from overheating, this structural material meets the strict requirements for flame-retardant properties, tracking resistance and design, according to technical key account manager Bernhard Helbich

The manufacturer of the entire charging system for the sports car is Leopold Kostal GmbH & Co. KG of Luedenscheid, a global system supplier of automotive, industrial and solar electrics as well as electrical contact systems. Charge controllers convert the three-phase or alternating current fed in from the charging station to direct current and control the charging process. During the process, they limit the charging voltage and current to prevent overcharging of the battery, for example. A current with an amperage of up to 48 amps flows through the plug contacts in the charge controller of the sports car, causing significant generation of heat during charging. “Our nylon is filled with special mineral heat-conducting particles that conduct this heat efficiently away from the source,” says Helbich. These particles give the compound a high thermal conductivity of 2.5 W/m∙K in the direction of melt flow (in plane) and 1.3 W/m∙K perpendicular to it (through plane).

The halogen-free flame-retardant nylon 6 material ensures that the cooling element is highly fire-resistant. As required, it passes the UL 94 flammability test of the US testing institute Underwriters Laboratories Inc. with the best classification, V-0 (0.75 millimeters). Its high tracking resistance also contributes to greater safety. This is demonstrated by its CTI A value of 600 V (Comparative Tracking Index, IEC 60112). Despite the high content of thermally conductive filler (68% by weight), the nylon 6 has good flowability. The heat-conductive thermoplastic also has potential for use in electric vehicle battery components such as plugs, heat sinks, heat exchangers and mounting plates for power electronics.”