How do the impact resistance and abrasion resistance of aromatic polyurea coating significantly reduce the risk of collision damage in electric vehicle battery bottom protection applications?
Publish Time: 2026-02-10
With the continuous increase in the popularity of electric vehicles, the safety and durability of the power battery, as one of the most core and expensive components of the vehicle, have received much attention. Especially in complex and changing road environments, the bottom of the battery pack is highly susceptible to mechanical damage from impacts by flying stones, scratches from speed bumps, and potholes. This can lead to minor issues like casing deformation and seal failure, or even internal short circuits and thermal runaway. To address this challenge, the application of high-performance protective materials has become a key line of defense. Aromatic polyurea coating, with its high strength, high toughness, 100% solids content, and excellent impact and abrasion resistance, is widely used in the protective treatment of battery bottom protection plates and top covers, and has been proven to reduce customer complaints caused by collisions and scratches by up to 90%.1. Molecular Structure Provides Excellent Impact ResistanceAromatic polyurea is generated by the rapid reaction of isocyanate and terminal amino resin, forming a highly cross-linked, dense network structure. Its molecular chain contains rigid benzene rings and flexible urea bonds, combining both hardness and elasticity. When the bottom of the battery experiences a sudden impact, the coating can quickly absorb and disperse the impact energy, preventing stress concentration in a localized area. This "softness overcomes hardness" mechanism effectively buffers the direct impact of external forces on the metal or composite material substrate, preventing casing dents, cracks, or weld tears, thereby protecting the structural integrity of the internal cells. Experiments show that battery guards coated with a 1.5–2.0 mm thick polyurea layer can withstand impact energy more than three times that of traditional epoxy coatings.2. Ultra-high wear resistance to resist long-term scratching and corrosionIn addition to instantaneous impacts, continuous friction during daily driving—such as gravel rolling, ice and snow scraping, and towing during maintenance—also threatens battery pack safety. Aromatic polyurea coating has extremely high Shore hardness and excellent wear resistance, far exceeding ordinary polyurethane or paint systems. Its dense, non-porous surface structure not only prevents the embedding of microparticles but also maintains coating continuity during repeated scratching, preventing corrosion or structural weakening caused by wear exposing the substrate. This long-lasting wear-resistant property ensures that the battery bottom remains effectively protected throughout its years of use.3. Seamless Integrated Film Provides a Comprehensive BarrierAromatic polyurea is applied using high-pressure airless spraying, allowing for rapid curing on complex geometric battery shield surfaces to form a seamless, pinhole-free, integral coating. This "skin-like" covering not only resists mechanical damage but also provides excellent waterproofing, corrosion resistance, and flame retardancy. Even in environments with salt spray, de-icing agents, or oil contamination, the coating effectively prevents the penetration of moisture and chemical media, preventing secondary damage caused by the expansion and corrosion of the metal substrate. Furthermore, its limiting oxygen index is typically above 28%, providing self-extinguishing properties and further enhancing the passive safety level of the battery system.
