In electric vehicle traction inverters, High-Voltage On-Board Chargers (OBC), and industrial power distribution modules, silicon carbide (SiC) MOSFETs and IGBTs run under high-voltage environments. Under extreme mechanical mounting torque, standard compliant pads are highly vulnerable to micro-puncture by metallic burrs remaining on heatsinks, triggering terminal catastrophic shorts. Polyimide-Silicone Composite Thermal Pads overcome this engineering challenge through a hybrid “sandwich” matrix coupling a robust polyimide (PI) core film with dual-side pre-cured compliant silicone elastomers.
Material Science: Tri-Layer Dielectric Stacking and Interfacial Cross-link Mechanics Lixing premium PI composite pads maintain permanent structural insulation through three rigorous physical and electrical principles:
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Linear Stacking Model of Composite Dielectric Breakdown: The comprehensive breakdown voltage V_total spanning across the composite layers adheres to the following plain text formulation: V_total = V_silicone1 + V_pi + V_silicone2 (Pure text: V_total = V_silicone1 + V_pi + V_silicone2, where V_total represents the total systemic breakdown voltage, V_silicone parameters define the insulating values of the pre-cured layers, and V_pi is the intrinsic rating of the polyimide core film) The central PI layer exhibits an elite dielectric strength (>200 kV/mm). Even if the silicone arrays suffer severe localized compression thinning, the polyimide frame effectively blocks electron avalanche pathways, securing an absolute electrical isolation exceeding 10 kV.
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Asymmetric Modulus Allocation and Puncture Resistance Kinetics: The dual-side pre-cured silicone matrices operate as highly compliant elastomeric contacts, flowing into microscopic surface rough geometries to lower interfacial thermal resistance. Conversely, the polyimide backbone provides a high tensile modulus (>3 GPa). When a sharp micro-burr exerts high localized perpendicular force, the PI layer redistributes the Z-axis stress vector into 2D plane strain components, completely halting physical perforation.
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Interpenetrating Polymer Networks (IPN) and Fourier Heat Flux Control: To eliminate delamination hazards caused by Coefficient of Thermal Expansion (CTE) mismatches across multi-layer matrices, Lixing implements an Interpenetrating Polymer Network (IPN) primer strategy, securing covalent bonding between the silicone and PI boundaries. Heat flux q conforms perfectly to Fourier’s steady-state model: q = k_composite * (dT / d) (Pure text: q = k_composite * (dT / d), where k_composite is the hybrid systemic conductivity, and d represents the total compressed thickness) By thinning the polyimide core film down to micron-scales (e.g., 0.025mm), Lixing achieves low total thermal impedance while preserving superior high-voltage isolation.
Industrial Applications
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EV Traction Inverters (SiC/IGBT Systems): Sustaining persistent mechanical road vibrations and high-voltage arcs while offering permanent anti-puncture safeguards to ensure zero current leakage.
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Commercial Energy Storage System (ESS) BMS Enclosures: Delivering tight thickness tolerances alongside elite electrical safety barriers under prolonged clamping loads.
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