Mechanical Properties of Elastomeric Foam-Based Compression Pads for Battery Pack Applications

With the increasing adoption of electric vehicles (EVs) worldwide, ensuring the long-term reliability and performance of the battery systems has become a paramount engineering challenge. Lithium-ion cells exhibit dimensional changes throughout their operational life, characterized by reversible “breathing”—expansion and contraction during charge and discharge cycles—and irreversible swelling due to aging. Compression pads are critical components for ensuring the lifetime performance of battery packs. The primary function of a compression pad is to act as a compliant cushion between cells. It accommodates these volumetric fluctuations by exerting consistent and optimized pressure. By absorbing the stress from cell expansion and maintaining structural integrity within the module, compression pads mitigate degradation mechanisms and ultimately maximize the durability and safety of the battery system over thousands of cycles. This paper highlights the importance of tailoring elastomeric-foam-based compression pads to meet the unique challenges of various battery formats and chemistries. We first characterize the fundamental mechanical properties of these pads under a range of conditions, such as different compression speeds and temperatures, that are directly relevant to realistic battery applications. Additionally, we demonstrate the pad’s long-term mechanical resilience by evaluating their performance over thousands of charge-discharge cycles at different operating temperatures, confirming their ability to maintain consistent pressure over a long time. Finally, we present advanced modeling and simulation approaches for compression pads. These predictive models are crucial tools to accurately forecast mechanical behavior and explore the design space virtually, accelerating the development of optimized solutions of compression pad for battery pack applications.