As the penetration rate of new energy vehicles continues to rise, thermal management of power batteries has become a core industry issue. The choice of potting materials directly affects the safety rating and service life of battery packs. Liquid silicone rubber (LSR) potting compounds, with their unique comprehensive properties, are becoming an important component in power battery protection systems.

From a technical mechanism perspective, the core performance indicators of LSR potting compounds include thermal conductivity, flame retardancy rating, electrical insulation strength, and resistance to high- and low-temperature cycling. Addition-cure LSR utilizes a platinum catalytic system, releasing no by-products during curing with extremely low shrinkage, making it suitable for deep potting of precision electronic components. Condensation-cure RTV relies on moisture curing, offering simple operation and controllable costs, and continues to see widespread use in scenarios with less stringent precision requirements. In terms of thermal conductivity, the addition of thermally conductive fillers such as alumina, boron nitride, or carbon fibers can increase the thermal conductivity of silicone rubber from a baseline of 0.2 W/(m·K) to above 1.0 W/(m·K), effectively alleviating heat accumulation between cells.

At the application scenario level, power battery module potting is currently one of the most important application areas for LSR. The potting compound fills the gaps between cells, forming thermal conduction pathways through the oriented arrangement of thermally conductive fillers to address uneven heat transfer between cells. At the same time, its flame-retardant properties (typically achieving UL94 V-0 rating) can slow the spread of fire in the event of thermal runaway. BMS circuit board protection represents another important area, where the moisture resistance, salt-spray resistance, and vibration resistance of the potting compound ensure stable operation of the battery management system under complex operating conditions. Additionally, in the sealing protection of charging pile power modules, long-term outdoor weatherability becomes a key consideration.

Different battery types impose differentiated requirements on potting compounds. Lithium iron phosphate batteries operate within a relatively moderate temperature range but demand high cycle life, requiring potting compounds with excellent aging resistance. Ternary lithium batteries have higher energy density and greater thermal runaway risks, imposing stricter requirements on thermal conductivity and flame retardancy. Solid-state batteries, as the next-generation technology direction, present new challenges for potting materials in terms of interfacial compatibility and chemical stability. In terms of production line compatibility, viscosity, working time, and curing conditions must be coordinated with production line cycle times. Addition-cure LSR can achieve rapid curing through heating, while condensation-cure RTV is more suitable for room-temperature still-air curing processes.

It is worth noting that lightweight potting solutions are becoming a research hotspot in the industry. Foamed silicone, by introducing microcellular structures into the matrix, reduces density while maintaining basic protection performance, contributing to improved energy density of battery packs. While this technology has made some progress at the laboratory stage, issues such as cell uniformity and long-term reliability still need to be addressed before large-scale industrial application.

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