As the demand for electric vehicles (EVs) continues to rise, automotive original equipment manufacturers (OEMs) focus on improving the longevity and increasing the power density of battery packs. Adhesive solutions help achieve these objectives; that is why acquiring knowledge on how to choose the best adhesive options for EV battery packs is essential. The main goals are two:
- Battery optimization: EV battery packs with higher longevity will save frequent replacements for the end user. Learning the most effective techniques to guarantee thermal control throughout in-service and charging procedures is necessary to accomplish this.
- Power density: EV battery packs must efficiently transfer power to drive electric motors. Lightweight solutions are crucial to increase the power density of battery packs to facilitate quick acceleration.
Bonding Solutions for EV Batteries
As an adhesive and sealants expert, Caplinq provides adhesive solutions for EV batteries for two major assembly sections:
Battery Cell Bonding
Battery Cell Bonding: The cells in the battery pack or module must be connected to provide insulation and protection against vibration and movement during the manufacturing process and throughout the battery’s lifespan. Additionally, cells must be attached to a frame or cold plate, depending on the battery type. By doing this, heat activity is reduced and impurities are kept out of the battery pack. It also keeps the structural integrity of the cells intact. The bonding application can vary by cell type, such as cylindrical, prismatic, or pouch cells.
Battery Pack Structural Bonding
Battery Pack Structural Bonding: In battery pack bonding, components like modules, housing, and other structural elements are joined to create a rigid and secure unit. Adhesives can be used to securely bond components, improving the strength and rigidity of batteries while making them lighter by eliminating the need for mechanical fasteners. Usually, two components of a battery pack are bonded together using a bead-shaped, one- or two-component epoxy. Accuracy and precision are essential for good bonding and effective material utilization. It is advised to use metering systems with durable equipment and good material control for handling extremely abrasive, medium-to-high viscosity materials.
The Role of Adhesives in Battery Pack Manufacturing
When selecting adhesives, consider their impact on both end-users during the operation of the battery pack in an EV, as well as on OEMs throughout the production process.
1. Battery Pack Performance
The right adhesive for EV batteries unlocks design freedom. Strong bonds allow engineers to utilize various materials, such as metal and nylon, for optimal performance. Choosing the right adhesive contributes in terms of thermal stability and environmental protection, achieving battery longevity. Thermally stable adhesives manage heat fluctuations, protecting battery components and extending charge life. Additionally, a strong environmental seal prevents harmful elements from entering the battery and causing damage. Choosing the right adhesive ensures both a well-designed and long-lasting battery pack.
2. Battery Pack Processing Efficiencies
Maintainability: For automotive OEMS, ideal EV battery adhesives simplify repairs, i.e., easy removal and resealing, while minimizing future maintenance needs. Flexible adhesives can reduce vibrations and external impacts, lowering repair costs. However, adhesive composition is crucial. Those with harmful solvents or monomers may require special handling and ventilation due to flammability or health risks.
3. Battery Pack Sustainability Enhancements
Electrical insulation: OEMs can design more energy-dense battery packs to improve vehicle performance for the end user by employing efficient electrical insulation techniques. Electrically insulating adhesives aid in this process. First, insulating separators with thin walls can be used to avoid short circuits. Insulating adhesives also reduce the number of battery cells short-circuits to each other while enabling high-voltage capabilities. More importantly, these adhesives stop a charge from propagating ineffectively.
How to Choose the Right Adhesive Technology
As there are several adhesive technologies that provide varying degrees of compatibility with EV battery packs, it is crucial to understand their distinct qualities to choose the best solution for your application. We will mostly focus on the three major candidates, leaving traditional acrylics and epoxies aside.
Silyl Modified Polymer (SMP)
SMP simplifies production with primerless adhesion. It exhibits broad material compatibility, such as in metals and plastics, and offers flame retardancy while being isocyanate-free for improved worker safety. The superior flexibility of SMPs compared to those of epoxies reduces vibration and extends battery life. It offers excellent elongation, fast curing, and variable open times, ensuring a strong seal against dust, moisture, and chemicals.
Our Silyl-Modified Polymer (SMP) solutions are versatile and can be used for glazing, bonding, and sealing applications to boost productivity. In addition to being 100% solvent and isocyanate-free, this alternative helps OEMs better meet the sustainability needs of EV end users while retaining flexibility and a high level of resistance to adverse conditions for an extended battery life. BS-7000 Series features high-quality elastic bonding adhesives based on SMPs. It is suitable for use as an adhesive on structures in industrial applications that require high strength. It has excellent UV and weather resistance and excellent adhesion performance on a wide variety of substrates, with minimal or no pre-treatment necessary. It can be overpainted with the most common industrial paints. Alternatively, the BS-7000F V3 SMP adhesive complies with the latest fire protection legislation, meeting the highest hazard levels according to the European Standard EN 45545. In addition, it demonstrates the mechanical properties necessary for elastic bonding. Qualities that make BS-7000F ideal for EV bonding applications.
Two-Part Polyurethane (2K PUR)
Like acrylic adhesives, 2K PUR adhesives bond to various materials (nylon, steel, aluminum) and offer odorless flame retardancy, reducing safety concerns. Their superior flexibility surpasses epoxies, and their handling of thermal expansion is better. Curing at room temperature or with heat allows versatile use on battery components while lowering energy consumption – a win for both manufacturers and environmentally conscious EV buyers.
In order to simplify the process of joining several components together, polyurethane adhesives can bond metals and thermoplastics. CAPLINQ’s two-part polyurethane adhesives do not require priming or other special handling to bond to metal. Additionally, this technology’s low viscosity allows for accurate gravity-flow bead dispense or continuous coverage streaming, enabling OEMs to maximize the usage of their adhesive supply while utilizing current equipment. Caplinq introduces the BS-9000 series polyurethane adhesive which is a 2-component, polyurethane-based adhesive. BS-9000 series is easily operatable and shows good adhesive performance with FRP, composite material, metal, and plastic substrate.
Reactive Hot Melt Polyurethane (HMPUR)
Similar to acrylic adhesives, heated HMPUR adhesives cure with moisture, offering strong chemical resistance for EV battery applications. Hot melt polyurethanes eliminate the need for special storage or ventilation due to their solvent-free composition. They outperform epoxies in vibration reduction and sound absorption thanks to their flexibility during curing, promoting a quieter and more durable battery.
We haven’t onboarded HMPUR yet but when it comes to Hotmelts, you can consider ur reactive BS-1000 V8 series Hot Melt Silicone which is specifically made for accurate manual or automated dispensing. The BS-1008 is a fast-curing, room-temperature-vulcanizing silicone sealant designed for bonding and sealing structural parts and electronic components in electronic and electrical products. It offers good flexibility and firmness, along with a wide working temperature range, excellent weatherability, and stable insulation performance to protect electronic products under harsh conditions. With good processability for various dispensing requirements, it is ready for use as supplied.
Caplinq is committed to assisting OEMs in creating EV battery packs that are made of premium adhesive solutions to meet performance and production requirements. Are you trying to find an adhesive that will improve the performance and manufacture of EV battery packs? Speak with our specialist to find out which adhesive solution is the best option for you.
