During the operation of photovoltaic modules, the diodes housed within the junction box act as the circuit's "guardians," responsible for providing bypass protection in the event of shading or system faults. However, as module power outputs increase and outdoor operating temperatures rise, the issue of "reverse leakage current" in diodes under high-temperature conditions has become increasingly prominent—elevated leakage currents can lead to localized overheating, power loss, and even thermal runaway breakdown. Phenyl raw rubber, leveraging its exceptional electrical insulation properties and thermal stability, serves as the diode's "high-temperature insulation guardian," effectively curbing potential leakage hazards at the packaging level.

The key to phenyl raw rubber's ability to suppress leakage current lies in its superior "volume resistivity" and "thermal compatibility." In high-temperature environments, conventional packaging materials are prone to forming microscopic pores or cracks due to intensified molecular chain segment motion; this leads to localized electric field concentrations and triggers surface leakage. In contrast, the phenyl groups introduced into the molecular chains of phenyl raw rubber not only elevate the material's glass transition temperature but—more critically—enhance the polarity and structural density of the molecular chains. This highly dense structure effectively fills the microscopic voids between the diode chip and the packaging housing, creating a "seamless" insulating barrier that significantly boosts volume resistivity and fundamentally severs the conduction pathways for leakage currents.

Furthermore, phenyl raw rubber's excellent "coefficient of thermal expansion matching" ensures that it maintains synchronized thermal deformation with the diode chip, lead frame, and housing materials across a wide temperature range of -40°C to 200°C. During the rigorous thermal cycling experienced in outdoor environments, the material resists cracking or delamination caused by thermal stress, thereby preventing corona discharge and localized electric field distortions that might otherwise arise from interfacial gaps. This combination of "rigidity and flexibility" in its thermomechanical properties ensures that the diode's internal PN junction remains situated within a stable electric field environment, effectively suppressing the exponential growth of reverse saturation current that can occur at high temperatures due to the activation of defect states. Furthermore, the inherent UV and humid-heat resistance of phenyl raw rubber enables it to withstand prolonged outdoor aging, thereby preventing conductive byproducts—resulting from material degradation—from contaminating the chip surface. Ranging from dense insulation at the molecular level to macroscopic thermal stress buffering, phenyl raw rubber leverages its exceptional properties—characterized by "high resistance at high temperatures and thermally stable insulation"—to resolve the critical issue of reverse leakage current in photovoltaic diodes operating under high-temperature conditions. It serves not only as a pivotal material for enhancing module reliability and power generation efficiency but also acts as the invisible guardian ensuring the sustained, long-term operation of photovoltaic systems over a 25-year lifespan.