44 pressure. This is critical in two-part applications with vastly different viscosities, preventing the higherpressure material from flowing back into the lower-pressure side when the dispense cycle begins. Since its release and first showing at The Battery Show, the SRP has been rapidly adopted. Its primary applications include applying thermal interface materials to manage heat in battery modules, and potting around individual battery cells with urethane or silicone foams to contain thermal runaway and prevent catastrophic failures. Wacker Chemical showcased its new generation of thermally conductive adhesives (TCAs) designed to meet the demands of rapidly evolving EV battery design, such as the shift from cell-tomodule to more integrated cell-to-pack and cell-to-chassis architectures. Branded GENIOSIL, these new TCAs are multifunctional bonding materials that must also manage heat, withstand extreme environmental stresses, and even allow for repair and recycling. This new family of TCAs is based on Wacker’s proprietary silane-terminated polyether (STP-E) technology, a hybrid system that bridges the performance gap between traditional material classes. “The polyether backbone gives siliconelike flexibility, while silane end groups cure into a siloxane network that adds mechanical strength and adhesion,” Wacker’s Alejandro Shimazaki explains. This unique structure allows engineers to fine-tune crosslink density, achieving an optimal balance of elasticity and durability essential for dynamic battery packs subjected to constant vibration and thermal cycling. The new adhesives are engineered to be isocyanate-free, solvent-free and tinfree – for health, safety and environmental reasons. Eliminating isocyanates removes exposure to potent respiratory sensitisers, simplifying compliance with OSHA and REACH regulations. The solvent-free nature means zero VOC emissions, improving indoor air quality and reducing fire risk on the production line. Furthermore, removing tin-based catalysts eradicates highly toxic, bioaccumulative compounds from the curing process, Shimazaki notes. Thermal ageing and shock are major concerns, often leading to cracking, embrittlement and loss of adhesion in conventional adhesives. The STP-E hybrid is specifically designed to resist these failure modes. “By combining a flexible backbone with a stable siloxane network,” Shimazaki notes, the adhesive can “absorb stress and maintain adhesion even under rapid temperature changes.” One of the most critical features for modern battery manufacturing and lifecycle management is reworkability. Unlike aggressive epoxies or acrylics that form permanent, brittle bonds within minutes, STP-E adhesives are designed with ‘smart curing’ in mind, meaning that they develop sufficient handling strength for assembly line throughput but can be selectively debonded for service or recycling. “It does not imply a fully reversible bond,” clarifies Shimazaki, “but the cured STP-E-based TCA can be selectively broken down using the right chemical agent or by applying gentle heat.” This controlled disassembly prevents damage to expensive battery cells and substrates, which is a common problem when removing components bonded with epoxies. While these TCAs deliver outstanding flexibility, chemical resistance and safety, they do involve calculated trade-offs. Compared with high-performance epoxies, they exhibit lower ultimate tensile strength (1–10 MPa versus 20–40 MPa) and a higher moisture vapour transmission rate. However, as Shimazaki points out, this sacrifice in peak strength and low permeability is a conscious one, made to prioritise “elasticity, durability and safer handling – making them ideal for dynamic joints and environments where flexibility matters more than brute strength.” The curing process is another area of customisation. Relying on moisturedriven hydrolysis, it can be tailored to manufacturing needs. “You can stick with standard moisture cure at ambient humidity, speed things up with heat or controlled humidity or use dualcure systems,” Shimazaki explains. This allows formulators to achieve the necessary handling strength and full cure profiles to suit high-volume production lines without necessarily increasing energy consumption. Show report | The Battery Show North America January/February 2026 | E-Mobility Engineering Wacker’s new SEMICOSIL thermally conductive adhesive combines siliconelike flexibility with adhesion and mechanical strength (Image: Wacker)
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