Continental Structural Plastics developed this multi-material battery enclosure, featuring CSP’s proprietary materials, at its Advanced Technology Center in Auburn Hills, Mich. The enclosure is reported to be 15 percent lighter than a steel battery box. (Photo: Business Wire)

Continental Structural Plastics develops honeycomb technology, multi-material battery case at Advanced Tech Center

 AUBURN HILLS, Mich.—A Class A honeycomb panel technology and a multi-material battery enclosure for electric vehicles (EVs) are among the innovative technologies recently developed by Continental Structural Plastics (CSP) to produce lighter-weight components with advanced properties. Both technologies were developed at CSP’s Advanced Technology Center, according to a release from CSP and its parent company, Teijin.

The Advanced Technologies Center, a 47,500-square-foot facility in Auburn Hills, is CSP’s second R&D facility in the city. It dedicates 24,000 square feet to R&D efforts to develop next generation materials and processes, the company said in the release.

Continental Structural Plastics’ new honeycomb manufacturing process is reported to produce “ultra-lightweight” Class A panels.  Considered a “sandwich” composite, the panels use a lightweight, honeycomb core, clad with natural fiber, glass fiber, or carbon fiber skins that are wetted with PUR resin. The process enables the molding of complex shapes and sharp edges, producing panels that combine high stiffness with low weight.

“We are developing technologies and processes here that leverage CSP and Teijin’s expertise in thermoplastic and thermoset composites, carbon fiber, and manufacturing to provide our customers with new options for their existing and future vehicle programs,” said Hugh Foran, executive director of business development, new markets and technologies, in the release. “We can lighten the vehicle while improving the strength and safety of its occupants—key features needed for autonomous, connected, and electric vehicles.”

The Advanced Technology Center team currently includes five engineers and designers. Continental Structural Plastics’ advanced technology department, in combination with R&D and product development services, comprises 80 engineers, designers, and scientists, the company said.

Continental Structural Plastics is currently involved in the development and production of more than 34 battery trunk covers of different electric vehicles in the United States and China. To expand its offering and provide customers with a superior battery case, CSP and Teijin have developed a multi-material battery enclosure, or case, that features a one-piece composite lid and a one-piece composite tray with aluminum and steel reinforcements. The EV battery enclosure can be molded in numerous composite formulations that are proprietary to CSP, the company said.

Automakers face several challenges with the current multi-piece, steel-and-aluminum EV battery enclosures, according to CSP. These include the overall weight of the case (typically more than 1,000 pounds) and the need for multiple welds, fasteners, and bolts, which can result in leaks. By molding the cover and tray each as one piece, CSP created a system that is reportedly easier to seal and can be certified before shipping. The company has two patents pending for its innovative assembly and fastening systems, CSP said in the release.

The company has also developed a mounting frame using a structural foam for energy absorption. This is said to reduce chassis thickness and weight, while improving performance in the event of a collision.

Overall, CSP’s multi-material battery case is reported to be 15 percent lighter than a steel battery box. Although it is the same weight as an aluminum case, the CSP case is said to provide better temperature resistance than aluminum, especially if the phenolic resin system is used. Because the one-piece design for the tray has no through holes, no sealant or putty is required. This eliminates the chances of leakage and reduces overall production costs and complexity, according to CSP.

Continental Structural Plastics said its materials R&D team developed an assortment of advanced composites that made many of these benefits possible. As a result, customers can select the formulation for the cover or the base that best meets their specifications. Options for the battery case materials include the traditional ATH system with high-fill polyester/vinyl ester filling; an intumescent system; and a phenolic system.

The traditional ATH system with high polyester/vinyl ester filling uses conventional sheet molding compound (SMC) chemistries. It is easily adapted to existing tools and is said to give “excellent baseline performance in the right design.” The intumescent system uses a chemistry similar to traditional SMC but is said to offer better flame retardance and thermal runaway.

The phenolic system is reported to be well-suited for high-temperature applications where parts must meet fire safety, smoke emission, combustion, and toxicity requirements. It is said to provide excellent flame retardance, heat and chemical resistance, and electrical non-conductivity.

Each of these chemicals can be adapted using different fiber types or formats and can be formulated to meet the most stringent CVO requirements, the company said.

“The work being done at the Advanced Technology Center, combined with advances in materials achieved in our head office research and development facility, allows CSP to maintain our leading position in advanced composites, and establish ourselves as a global player in the multi-materials field,” said Steve Rooney, CEO of CSP, in the release. “Together with the carbon fiber and materials expertise that Teijin brings, we are developing light weight solutions that enable our customers to think outside the box when it comes to vehicle design.”

The Advanced Technology Center was a Teijin R&D center, where the Sereebo® manufacturing process was developed, before CSP was acquired by Teijin. Sereebo is the process currently used to manufacture the GMC Sierra Denali CarbonPro® pickup box, the industry’s first carbon fiber pickup box.

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