New Lightweight Battery Housing Solution: How STM Process Is Reshaping EV Supply Chain?

The challenge of balancing safety and cost in electric vehicle batteries is driving cross-material process innovations. At the Battery Show Europe in Stuttgart, Germany, from June 9 to 11, automotive supplier Autoneum showcased a battery lid component manufactured via spray transfer moulding (STM). This component is not a traditional metal part or pure plastic; it is a multifunctional composite structure that integrates fiber and resin, directly contributing to simplified battery pack design and enhanced safety performance.

Substantial Breakthrough in Process Path

The STM process is familiar in the textile industry: short-cut fibers and resin are simultaneously sprayed onto a mold surface for rapid forming. However, applying it to power battery lids requires coordinated solutions for fiber orientation, resin impregnation, flame retardancy, and insulation. Autoneum's component achieves multifunctional integration—sealing, insulation, vibration damping, and thermal management in one part—simplifying overall battery pack design.

From a textile composite perspective, this development signals two key trends. First, nonwoven or short-fiber reinforced composites are penetrating from interior trim and underbody shields into safety-critical components like battery housings. Second, cost-effective rapid forming processes are breaking the dominance of carbon fiber prepregs in high-end applications, offering a viable lightweight path for mid- and low-end vehicles.

Implications for Textile Industry Clusters

What does this mean for domestic textile composite enterprises? Currently, the domestic battery housing market is dominated by aluminum and steel, with composite penetration below 5% but growing at over 30% annually. The maturation of STM will directly reduce mold investment and per-unit costs for composite battery housings—traditional autoclave or high-pressure RTM processes require molds costing millions of yuan, while STM molds can cut costs by over 40%.

For industry clusters like Shengze and Keqiao, which focus on woven and knitted fabrics, directly entering STM production involves equipment barriers. However, upstream segments—short-cut fiber supply, functional coating finishing, and prepreg development—are precisely where textile enterprises can contribute. Flame-retardant fibers and electrolyte-resistant coating technologies remain largely at the laboratory stage domestically, with limited mass production capacity.

Practical Recommendations

For Purchasers - Evaluate fiber suppliers for STM processes: focus on wettability, dispersion uniformity of short-cut glass and carbon fibers, and flame-retardant modification solutions. - Require full electrolyte immersion test reports: material stability in long-term contact with electrolyte is more critical than mechanical strength. - Compare mold amortization costs: for projects under 100,000 units per year, STM's total lifecycle cost may be lower than metal stamping or traditional autoclave processes.

For Export Enterprises - Certification cycles for composite battery housings by European OEMs typically take 12-18 months; establish joint development relationships with Tier 1 suppliers rather than submitting samples alone. - Monitor EU Battery Regulation (EU 2023/1542) on material recyclability: recycling solutions for thermoset resins in STM are not yet mature, and biodegradable or thermoplastic matrix alternatives will become export barriers. - Leverage exhibition channels for technical dialogue: the showcased component has entered mass production validation; proactively contact Autoneum's procurement to understand their short-cut fiber supplier qualification standards.