Innovative Materials for Lightweight EV Battery Enclosures

As the electric vehicle (EV) share of the automobile market continues to grow, the new means of propulsion has created the need to take a fresh look at automotive design, engineering and manufacturing. The automobile industry is demanding lighter, stronger and safer products, and the engineering materials experts at Envalior are meeting those demands with innovative new materials.  

Speaking at the Society of Plastics Engineers (SPE) 2024 Electric & Autonomous Vehicle (EAV) conference in Troy, Michigan,  Keith Kauffmann, Automotive Application Development Engineer, Envalior Americas, presented a session on the creation of the first fully functional high-voltage battery enclosure made entirely of engineering plastics. 

The battery tray, a joint development between Envalior and Kautex Textron, was retrofitted into a VW ID.3 EV. System level testing was completed and field testing in vehicles is currently underway. 

“The structural battery enclosure combines innovative materials and functional integration, resulting in a lightweight and cost-effective solution over the baseline metal design,” said Kauffmann. “It represents a lower cost, lower weight and lower carbon footprint solution than the metal design.”

The prototype battery tray is made from Envalior’s Durethan® B24CMH2.0 (PA6) combined with direct long-fiber technology (D-LFT), resulting in 45% long glass fiber in the end product. The battery tray is reinforced with Tepex thermoplastic composite sheet technology.  

The PA6 non-reinforced product is specifically tailored for D-LFT compression molding. It is long-term heat stabilized up to 160°C, stabilized for processing exposed to air/oxygen, optimized for less emissions (e.g. smoke, fumes) and flows easily for excellent filling behavior with reduced clamping force.

Keith Kauffmann receives a session certificate from Jeff Helms, SPE session chairperson.

When combined with compression molding, D-LFT allows the molder to readily modify the glass content (if needed) and also allows the freedom to change glass type or change to carbon fiber. It is suitable for geometries with significant changes in wall thickness. 

Compression molding also enables the optional combination of D-LFT with Tepex  composite sheets, a solution for structural enhancements and improved protection from thermal runaway. 

The realized advantages of thermoplastic battery enclosures include:

  • Single compression molding step  
  • Part and function integration 
  • Significantly reduced assembly steps 
  • Overall reduced costs 
  • High recyclability potential with lower carbon footprint 
  • Weight savings over the aluminum design 

“The single-piece design provides better dimensional tolerances than multi-piece trays, and the simple construction requires less production space,” Kauffmann said. “A reduced number of suppliers means less logistics and more material consistency.” 

In addition, it delivers on the EV industry’s stringent fire resistance tests and electromagnetic shielding (EMS) requirements by adding mica sheet and aluminum foil. 

We believe that smarter use of materials and more advanced materials will lead to further parts consolidation for applications like the battery enclosure,” Kauffmann said. “For example, although mica sheet was needed for thermal runaway protection, we believe that Tepex offers potential for thermal runaway protection that can be incorporated into the battery enclosure top cover.” 

As a solutions provider, Envalior offers numerous solutions for both compression molding and injection molding with in-house engineering knowhow to support design and engineering.

Kauffmann concluded, “We are seeing more pull from the marketplace for plastic battery enclosures to address cost and weight. Although compression molding was selected for this battery enclosure prototype, injection molding technology exists for molding these very large parts. The main benefits of injection molding are greater functional integration and process repeatability. Envalior offers a wide range of materials and engineering solutions to help our customers meet their performance and cost targets for battery enclosures.” 




Candace Roulo

Global Manager of Messaging and Content Development

Candace Roulo is Global Manager of Messaging and Content Development for Envalior. Based in Troy, Michigan, she specializes in writing blogs and articles about advanced materials solutions. Prior to joining Envalior, Candace served in editorial roles at SME and Penton Media. Candace earned her bachelor’s degree in communication, specializing in public relations, at Michigan State University’s College of Communication Arts and Sciences.

Published on

23 April 2024


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