Mind the Gap!

As mentioned in the introduction, battery systems for electrified rail and mass transport face unique challenges due to the high vibration, extreme temperatures, and heavy loads to which they are subjected. These challenges are also relevant for battery-electric heavy-duty industrial applications, such as trucks, forklifts, agricultural or construction vehicles.

Although based on comparable technologies used in electric car batteries, there are still differences in operating conditions, requirements, and challenges faced by batteries in mass transport and heavy-duty machinery.

These challenges can cause significant damage to the battery and reduce its performance, safety, and lifespan. For instance, high vibration can cause internal damage to the battery cells, while extreme temperatures can lead to thermal runaway and even fire. There is a critical need for solutions that can address these challenges and ensure that battery systems in rail and mass transport applications are safe, reliable, and long-lasting. Advanced silicone materials are currently the preferred choice. Let us explore the how and why in more detail.

Silicone pads used in heavy-duty battery applications are typically made of high-quality silicone rubber material specifically designed to endure the harsh and demanding conditions of these industries. Depending on their use in cell-to-cell or cell-to-pack, thermal interface, or cushioning applications, the exact type of silicone pad is adapted to the specific requirements, operating conditions, and the desired level of protection needed.

• Cell-to-cell or cell-to-pack silicone compression pads: Depending on the battery pack design, these silicone materials are used to provide defined pressure on the cells, enabling optimal cell performance and extended lifespan during expansion and compression. Additionally, they help mitigate thermal runaway propagation by creating insulation barriers between adjacent cells.
• Thermal Interface silicone materials: In mass transportation and heavy industry battery applications, the enormous amount of power in a short time can cause extreme temperatures in the battery, potentially putting the entire system at risk. TIM (Thermal Interface Materials) made of silicone are ideal for dissipating heat away from the system.
• Vibration dampening and cushioning silicone materials: Due to specific densities, thicknesses, and material design, silicone cushioning pads help reduce vibration, improve thermal management, and enhance shock absorption in battery systems.

Overall, the unique combination of thermal properties, customisable densities, and compression-force-deflection (CFD) properties, as well as strong resistance to electrical, chemical, mechanical, and environmental stresses, makes silicone pads the preferred choice for high-end battery applications in mass transportation and heavy industry.

Silicone pads offer improved battery performance and efficiency, enhanced safety and reliability, as well as a longer battery lifespan, making them highly appealing to engineers designing high-end batteries with high power density. New technologies and material combinations, such as those with mica or adhesives, often make these materials the unseen champions that can make a significant difference.

Even though silicones offer premium functionality, there are other promising polyurethane-based solutions that also have excellent properties and advantages in specific applications. So, how do you find the most suitable solution?

With EV engineers across the globe working on innovative and ever more powerful battery designs, there is no one-size-fits-all solution for battery pads. This makes identifying the right solution a true challenge, but there are some key factors to consider when selecting silicone pads for rail, marine, aircraft, agriculture, industrial and mass transportation battery applications, such as:

• Material composition
• Density
• Temperature range
• Vibration damping properties

There are numerous solutions available, and to make it even more complex, there are many ways to modify existing standard solutions or to customise and co-develop new application-specific products. No product guide, selector or well-developed tool can currently provide the perfect solution at the touch of a button. Especially, as the pace of new developments and technologies is astonishing. The best approach might still be to speak to your expert, provide application details, must-haves and potential hurdles. This article can help you understand the importance of these materials, give certain directions and help start the discussion with your expert of choice.

With battery-electric mobility on the rise and new technologies opening new dimensions, silicone pads can be the turbocharger for batteries in EVs, trains, aeroplanes, marine, mass transportation and industrial applications. Be sure you "Mind the (silicone) Pad" and talk to your tape expert as these innovative materials could be the key that turns challenges into battery-electric solutions.