The specialty chemicals company LANXESS and the Hella Hooker Group of companies have jointly developed a new composite material called PocanAF4130, which is the housing material for a cell management unit (BMU) and two cell detection units (CMU). The significant advantages of this material are the extremely low warpage and expansion and the high flame retardancy.
The polybutylene terephthalate (PBT) and acrylonitrile-styrene-acrylate copolymer (ASA) blend contains 30 percent by weight glass fibers and a halogenated flame retardant package. "We see great potential for the application of this material in precision parts for automotive battery systems." said Marc Marbach, sales director of LANXESS' High Performance Materials (HPM) division. The process took a total of two and a half years from the initial idea, through extensive testing at a later stage and finally into full production use.
Lanxess and Hella Hoeker develop new composite material together
These extremely flat devices are currently used in lithium battery systems for small cars in Germany.
Low deviation
The BMU and CMU housings have a large flat surface with complex geometry around the edges and inside. It is these innovative designs that allow the BMU and CMU housings to be injection molded as individual parts, saving costs. When the housing is mounted on a printed circuit board, the contact terminals of the connection posts cannot be mixed together. The spatial distance deviation between the connection posts is extremely small, resulting in a small cutout for the contact terminals as well. "This is why our hybrid Pocan AF4130 has such amazing dimensional stability." Marbach explains.
Listed with UL945VA and ULf1
UL94 fire resistance test results from Underwriters Laboratories show the material has the best V-0 (0.75 mm) and fully meets the requirements of the above-mentioned German small car lithium battery system application. the UL Yellow Card describes this material as a premium UL945VA (1.5 mm). This material will eventually be used for injection molding of flame retardant case components. In addition, Ulf1 shows says the material can also be used in outdoor applications, where it can be lifted from UV light and water. "Therefore, our composite material can also be used in electronic components such as photovoltaic plugs and sockets." Marbach said.
Low volatility and emissions within tolerable limits
Analysis conducted jointly by LANXESS and VDA 278 (German Automotive Industry Association) shows that the material, which is made from thermoplastics on the surface part, has low emissions. "It therefore also fits well with the requirements of many automotive applications such as interior car parts, i.e. low volatility and emissions within tolerable limits." Marbach said.
Good resistance to common battery electrolytes
The blend is highly resistant to typical media used in automobiles, such as fuels, petroleum, detergents, and car care products. To prove this, LANXESS conducted extensive media storage tests for Hellahuck to LV124 supply specifications. LV124 is used by many automotive manufacturers and this blend has also shown good resistance to the media widely used in lithium batteries. In this regard, overload tests have also been carried out according to DINEN 22088-3.
Comprehensive HiAnt service
LANXESS has provided additional support to Hellahuac in the development of housing components. These services are part of the HiAnt consumer service package. For example, HPM advised on optimizing component design, provided material property data needed for the computer-aided design of all housing components to meet expected loads and performed mold flow analysis to help with initial injection molding trials. This specialty chemical company also performed odor testing of VDA270 by ion chromatography for Hellahuck to further confirm the halide content of this blend.
