In electric vehicle wireless charging systems, the transmitting and receiving coils serve as the core components for energy transfer. To ensure the coils maintain their electrical insulation and mechanical stability under complex operating conditions, the encapsulation process is of paramount importance. However, the internal stresses generated by traditional encapsulation materials during curing and thermal cycling often lead to "stress cracking" in the coils; this not only compromises the insulation layer but may also trigger catastrophic short-circuit failures. Phenyl gum, with its unique molecular structure and exceptional ability to modulate elasticity, offers an innovative solution to this persistent challenge.

The core advantage of phenyl gum lies in its molecular chain design, which strikes a perfect balance between rigidity and flexibility. By introducing phenyl side groups into the polysiloxane backbone, the rigid structure and steric hindrance effects of the phenyl rings serve a dual purpose: they inhibit excessive slippage of the molecular chains at high temperatures (thereby preventing material softening) while simultaneously facilitating the release of internal stresses through the flexible linkages provided by the phenyl groups. This unique structural configuration ensures that encapsulation compounds based on phenyl gum exhibit a shrinkage rate of less than 0.1% during the curing process—significantly lower than that of epoxy resins (>2%) or standard silicone rubbers (~1%)—thereby eliminating "shrinkage cracks" caused by volumetric contraction at the very source.

In terms of thermal stress buffering, phenyl gum demonstrates remarkable elastic adaptability across a wide temperature range. During operation, wireless charging coils generate high-frequency alternating magnetic fields and Joule heating, causing rapid temperature fluctuations within a range of -40°C to 150°C. Phenyl gum possesses a glass transition temperature as low as -115°C, allowing it to retain its rubber-like elasticity even in cryogenic environments and preventing the material from becoming brittle. Concurrently, the incorporation of phenyl groups ensures that the material's coefficient of thermal expansion closely matches that of the copper coils (17×10⁻⁶/°C); in thermal cycling tests involving 200 cycles, the interface between the encapsulation layer and the coil remained free of delamination or cracking, effectively mitigating the "shear stress" induced by disparities in thermal expansion coefficients.

Furthermore, the high damping characteristics inherent to phenyl gum serve to further enhance the encapsulation layer's resistance to cracking. The phenyl side groups within its molecular chains are capable of dissipating mechanical vibration energy into thermal energy through micro-Brownian motion; this enables the potting compound to achieve a damping factor (tanδ) of 0.25–0.35—twice that of ordinary silicone rubber. This means that when vehicle operation generates vibrations, the potting layer can actively absorb impact energy, thereby preventing stress concentration at the vulnerable points of the coil's enameled wires and averting the formation of "fatigue cracks."

In terms of process compatibility, the phenyl-based raw rubber potting compound exhibits excellent flowability and wettability. Its low viscosity (<500 mPa·s at 25°C) allows it to penetrate even the minute crevices within the coil structure; upon curing, it forms a seamlessly filled elastomeric network. This not only enhances insulation strength (achieving a breakdown voltage of >25 kV/mm) but also, through a "holistic encapsulation" effect, anchors the coil within a composite structure that harmonizes rigidity with flexibility—thereby definitively resolving the persistent issue of cracking associated with the "hard-on-hard" interactions characteristic of traditional rigid potting materials.

Through innovative molecular design, this phenyl-based raw rubber material integrates the attributes of "low shrinkage, high elasticity, and strong damping" into a single solution. It has not only resolved the critical challenge of stress-induced cracking in wireless charging coil potting but has also, through its flexible material design, driven a significant upgrade in the reliability of wireless charging technology for electric vehicles—offering a novel paradigm for the protection of core components in new energy vehicles.