Unravelling the Solutions that Help Mitigate Fire Risk and Spread
Without a doubt, thermal runaway protection (TRP) continues to be a key concern when it comes to high-powered electric batteries. As electric vehicles (EVs) become more advanced with improved motor performance, higher capacity and extended driving range, the path ahead will require game-changing materials to help provide a positive impact on thermal safety. These materials will have to support OEM customisation requirements to maintain intelligent battery safeguards, while helping to support electrifying new innovations.
Saint-Gobain® Tape Solutions has a wide range of customisable solutions that can help mitigate fire risks and propagation, improve thermal management as well as aid in managing cell swelling to reinforce battery safety.
We’d like to introduce you to Dr. Fei Wang, the subject matter expert on solutions that make a real impact on thermal safety.
Dr Wang is the Global R&D Manager for EV at Saint-Gobain Tape Solutions and has a PhD in polymer science from MIT. She joined Saint-Gobain in 2010 and has been actively developing new product solutions for various applications.
Her expertise lies in the development of products that mitigate thermal propagation and manage cell swelling in batteries for EVs.
We’ve asked Dr Wang a few questions regarding the technical article and, more specifically, about the role of compression pads and how they affect thermal stability.
Dr. Wang, could you please provide a short summary of the “Material Solutions for Battery Pack Thermal Runaway Propagation Protection” article?
Yes, I do not wish to reveal too much detail as I hope interested parties will take the time to review the article's content. The main aim of the article was to explain how our TRP products can combine thermal runaway protection functions with other features such as cell-to-cell cushioning, electrical insulation, gasketing, and sealing. At Tape Solutions, our objective is to provide our customers with multifunctional solutions. This article highlights some of those solutions.
What is the role of compression pads and how do they work in relation to TRP?
Lithium battery (LIB) cells are stacked in a configuration such as a module or a pack to achieve high-energy density for EVs. Such a design requires an outer bracing to maintain mechanical integrity and safety, which applies external pressure to the LIB cells’ surfaces after assembly.
When in use, LIB cells undergo a reversible thickness change during the charge/discharge cycle (“breathing” mode) and a gradual irreversible increase in thickness over their lifespan (“swelling” mode). Significant internal stress builds up within the LIB cell stack under the mechanical constraints of the module or pack. Many studies have reported that both too low and too high pressure negatively impact cell lifetime performance due to various factors, including electrode layer delamination, Li-plating, SEI (solid electrolyte interphase) growth, and others. Controlling the pressure exerted on LIB cells within an optimal range is crucial to improving cell efficiency and prolonging cell lifetime.
We have high-performing compression pad technology to effectively manage the pressure on LIB cells; one family of compression pads provides thermal runaway propagation protection through thermal stability and insulation.
ASTM test methodology is the most common, but what if the customer application is different?
To answer this question, let’s look at compression pad as an example. Cell breathing is much slower than in a typical ASTM (American Society for Testing and Materials) test method. Because of this, our team carries out testing at different compression speeds and uses material simulation to better understand how materials perform in real-life situations.
The bottom line is that battery designs vary. To best support our customers in achieving their ideal design, we need to have a conversation and explore capabilities and options. Please don’t hesitate to get in touch with us to find a solution together. Through a collaborative approach, we work across functions to seek effective solutions that will perform today, but also lead us towards a more sustainable future. With R&D colleagues such as Dr Ying Wang and Dr Sheng Zhao, we’re committed to being your dependable partner for specialised product development and new innovations.
Our R&D focuses on pioneering high-performance products, driven by a commitment to innovation and customer-focused solutions. Emphasising sustainability, we are concentrating on reducing carbon emissions and adopting circular economics to promote a more resilient future. For instance, we are developing more sustainable silicone products using recycled raw materials, which could achieve over a 60% reduction in CO2 emissions compared to silicone products made from virgin materials. We also plan to introduce silicone products with extremely low levels of off-gassing of cyclic siloxane.
— Dr Ying Wang, R&D Manager, Silicones Core Technology
At Tape Solutions, our primary goal is to ensure that you, our customer, are part of the conversation, whether it involves enhancing current solutions or coming up with something entirely new. We know that several existing options can help secure thermal protection at optimal levels, and we are committed to research and development of products that can help balance the safety, performance, and longevity of the heart of your EV – the battery pack.