When automotive OEMs design and produce EVs, there is a fundamentally different engineering process that takes place. Engineering thermoplastics like PBT and PBT blends have potential for many applications in the EV battery sector. Although especially PBT has been widely utilized in electrical and electronic automotive components, it may be challenging to find a material specifically for battery components. Certain requirements must be met, and so Envalior and Hella tailormade Pocan AF4130 material to use for BMU and CMU housings that fulfills battery-specific needs—it is resistance to heat and chemicals.
Electric vehicles (EVs) are here to stay and trending upward – according to the new edition of the IEA’s annual Global Electric Vehicle Outlook, more than 10 million electric vehicles were sold worldwide in 2022 and sales are expected to grow by another 35% this year to reach 14 million. Thus, EVs are being developed and produced to meet this sales growth. When automotive manufacturers design and manufacture these battery powered vehicles, there is a fundamentally different engineering process that takes place.
POCAN® (PBT and PBT blends) has been successfully utilized in many electrical and electronic automotive components, including sensors, connectors, and actuator housings. However, you may be challenged to find a material specifically for battery components because the material must meet certain requirements, such as being resistant to battery electrolytes, heat and chemicals.
In an EV, the battery management unit (BMU) and cell monitoring unit (CMU) are extremely important. The CMU collects and monitors battery data and is responsible for the charge, health and state of the battery. If the battery is in a critical condition the BMU determines the cause and controls countermeasures with the vehicle’s energy management system. This prevents the battery from overcharging or undercharging, which can damage the battery.
Housing components for the BMU need to be compact, flat, integrated and fire-resistant certified. The housing’s function is to control high-voltage current sensors and insulation monitoring units in batteries for EVs and hybrid vehicles. For the CMU, functions are integrated, which is why its geometry is complex. Therefore, the material utilized needs to have low warpage to facilitate the complex design.
To meet all these application requirements, we developed with Hella a material for BMU and CMU housings. We drew on our experience with low-warpage and flame retardant PBT material blend for safety critical electronic components for EVs. The result of our collaboration is Pocan® AF4130, a 30 wt.% glass-fiber reinforced, low warpage blend of PBT+ASA containing a low-volatile halogenic flame retardant package. Pocan® is known for its impressive resistance to heat and chemicals, outstanding electrical properties, strength and hardness.
A thermal desorption analyses was conducted , in which the emissions of volatile organic compounds and condensable from non-metallic auto materials were determined in accordance with the standard German Association of the Automotive Industry. This makes the material very suitable for applications that require low emissions, such as interior components.
Several chemical media storage tests were conducted too, to determine the chemical resistance of the blend. The selected material passed all the tests that exposed the material to oils, fuels, cleansers and car care products. No surface damage occurred during any of the tests.
Also, an analysis of the resistance of the material to an electrolyte of commercial origin used in lithium ion batteries was conducted under load-free exposure and visual inspection, and under load. The test specimens were exposed to an electrolyte vapor. No visible cracks were detected in the blend material.
Our HiAnt® customer service team supported Hella by making suggestions about component design and provided characteristic material data required for CAE design of the housing parts to meet the expected loads. In addition Envalior made suggestions for the mold flow analysis and supported the injection molding trials onsite. For Pocan® AF4130, using ion chromatography a content of free ionic halogenides below 10ppm was confirmed and odor testing according to VDA270 has been conducted.
Global Business Director PBT
Marc Marbach is global business director PBT for Envalior. In this global role, he focuses on effective management and optimization of the PBT business line to drive overall business success. Before taking over his current position, Marc has held various positions in technical and commercial areas in Hong Kong, from 2008-2012, and Germany, including technical marketing E&E, project management, global key account management and head of sales segment E&E.
08 April 2024
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