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:
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.
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.
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
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.
Commercial Energy Storage System (ESS) BMS Enclosures: Delivering tight thickness tolerances alongside elite electrical safety barriers under prolonged clamping loads.
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