Automotive and heavy truck composite components supplier Continental Structural Plastics Inc. has developed a multimaterial electric vehicle battery enclosure that meets stringent performance standards for flammability and other issues while offering a low tooling investment and overall lower product cost, it says.
Auburn Hills, Mich.-based CSP showcased its new honeycomb, electric vehicle battery enclosure technologies and proprietary material formulations, developed at its new 47,500-square-foot Advanced Technologies Center, at a virtual event Dec. 9.
CSP developed four main composite materials for more than 34 different models of battery covers, said Hugh Foran, executive director of CSP's Advanced Technologies Center. The new composites allow CSP to mold "different packaging features" that wouldn't be possible with steel or aluminum stamped parts.
Meeting various environmental requirements for customers across Asia, Europe and North America, Mike Siwajek, vice president of research and development at CSP, said, is "becoming one of the biggest hurdles in composite material."
"We consider ourselves material neutral," he said. "Whatever our customers need, we hope to be able to provide for them."
"We have materials that will exceed the temperature resistance of aluminum," Foran said. The company hopes to grow in the market, he added.
A new full-sized, multimaterial battery enclosure features a one-piece composite cover and a one-piece composite tray with aluminum and steel reinforcements.
"This is a fast-evolving market," Siwajek said. "As the OEMs learn and understand how the lithium-ion batteries perform and [with] some of the challenges they have for safety, we have to adapt very quickly. … New tests pop up every day."
The high-strength, low-density formula SMC battery enclosures also offer a low tooling investment, mass reduction and overall lower product costs, CSP said. By molding the cover and the tray each as one piece, the enclosure is easier to seal and can be certified prior to shipment.
Even though the box is equal in weight to an aluminum enclosure, it offers better temperature resistance than aluminum, specifically when its phenolic resin system is used, CSP said. It is 15 percent lighter than a steel battery box.
CSP's battery enclosure development includes not only the cover, but also compatible trays and frames, Foran said, which have also been crash and flame tested.
It is "designed to handle a battery pack that's in excess of 500 kilograms," he said. "That's a huge amount of weight that tray has to be able to carry."
The company has two pending patents for the box assembly and fastening systems.
Although honeycomb technology has "been around for quite a while," Foran said, CSP has created a way to make the process faster and reduce the weight of the product.
"Instead of having two molded SMC panels bonded together, we're using either an SMC or a thermoplastic skin and then putting the honeycomb panel behind it," Foran said, "then use the honeycomb for reinforcement underneath."
CSP's honeycomb panels, he added, "can be about 25 percent lighter than an SMC-SMC panel" and are "significantly less expensive."
The "eco-capable" honeycomb is sprayed first with polyurethane and then glass before it is formed into different shapes "with low-pressure and a fast cycle."