THERMINSYNX™

Definition

THERMINSYNX™ is a proprietary family of thermal spacer and propagation‑barrier materials from Mitsubishi Chemical Group, engineered primarily for use in electric‑vehicle (EV) battery modules and packs. The materials are designed to impede heat transfer and help mitigate cell‑to‑cell thermal runaway propagation while maintaining precise mechanical spacing and providing electrical insulation and flame‑retardant performance.

Key properties or functions

  • Thermal runaway mitigation: Formulated to interrupt or slow conductive, convective, and radiant heat transfer between adjacent cells, supporting pack designs that limit or prevent propagation.
  • Thermo‑mechanical control: Tuned compressibility, stiffness, rebound, and dimensional stability to maintain gap control under clamping pressure, vibration, and temperature cycling typical of EV operation.
  • Electrical insulation: High dielectric strength and volume resistivity to preserve isolation and creepage/clearance in battery assemblies.
  • Heat and flame resistance: Flame‑retardant chemistries (e.g., targeting UL 94 ratings) to withstand high‑temperature events and maintain barrier function.
  • Environmental and chemical resistance: Stability against humidity, electrolytes, and common automotive fluids; low outgassing/volatility for enclosure compatibility.
  • Reliability: Resistance to compression set, thermal aging, and mechanical fatigue across automotive operating and storage temperature ranges.
  • Integration and manufacturability: Available in multiple thicknesses and formats (e.g., sheets, pads, films, molded spacers, die‑cut parts), with options such as pressure‑sensitive adhesive (PSA) layers for assembly.

Relevance

  • EV battery safety: Supports OEM safety goals by helping contain or delay thermal runaway propagation, a critical requirement for high‑energy lithium‑ion battery systems.
  • Design flexibility: Enables tighter packaging and higher energy density by providing a robust, space‑efficient thermal barrier with controlled mechanical compliance.
  • System performance: Complements active cooling and thermal management strategies by providing insulation where heat should not flow, while maintaining electrical isolation and structural integrity.

Typical applications

  • Cell‑to‑cell spacers or partitions in cylindrical, prismatic, and pouch‑cell modules.
  • Inter‑module barriers or compartmentalization within packs to localize thermal events.
  • Edge, end‑plate, or cover liners intended to shield adjacent components from hot gases or localized heat during fault conditions.

Related terms and distinctions

  • Related functional terms: Cell‑to‑cell thermal barrier (CTB), thermal propagation barrier (TPB), thermal spacer, battery safety spacer.
  • Distinction from TIMs: Unlike thermal interface materials (TIMs), gap fillers, or thermal pads that are engineered to conduct heat to a sink, THERMINSYNX™ is intended primarily to insulate and control propagation while maintaining spacing and electrical isolation.
  • Technologically related categories (not synonyms): Microporous or aerogel‑based insulators, mica/ceramic paper barriers, flame‑retardant polymeric spacers.

Data typically specified (by grade)

  • Geometry and mechanics: Thickness range, density, compressive stress–strain behavior, compression set/creep, tensile or shear properties.
  • Thermal properties: Thermal conductivity (typically low for barrier function), thermal diffusivity, specific heat, temperature rating.
  • Electrical properties: Dielectric breakdown strength, volume/surface resistivity.
  • Flammability and safety: UL 94 rating and other automotive/flame performance metrics.
  • Environmental performance: Humidity/temperature aging, chemical compatibility, outgassing/fogging characteristics.
  • Processing/assembly: Available formats, die‑cutting/molding options, adhesive layers, reworkability.

Notes

THERMINSYNX™ is a proprietary portfolio; detailed composition and exact performance values vary by grade and application and may not be fully disclosed in public sources. Selection is typically driven by propagation‑resistance targets, available packaging space, required electrical insulation, assembly method, and durability requirements for the specific battery architecture.