Thermal Interface Material (TIM)

Introduction

Thermal management is a critical aspect of Li-ion battery safety and performance. The development of effective Thermal Interface Materials (TIMs) is essential to mitigate the risks associated with thermal runaway, a condition where an increase in temperature can lead to a self-sustaining reaction causing the battery to overheat, catch fire, or explode. In this study, we tested Electo TIM, a novel thermal interface material, in Li-ion batteries to evaluate its effectiveness in preventing thermal runaway and its suitability for practical applications.

Experimental Setup and Methodology

We conducted a series of tests to examine the performance of Electo TIM under high-stress conditions. The experimental setup involved inducing a high current to a single Li-ion cell until it reached a failure point, causing the cell to blast. The primary objectives were to measure the peak temperature during the blast, observe the temperature behavior of adjacent cells, and assess the overall thermal management capabilities of Electo TIM.

Results and Discussion

Temperature Behavior

The induced high current caused the Li-ion cell to blast after approximately 8 minutes, reaching a temperature of 200°C, with the temperature peaking at around 500°C. Remarkably, the temperature of adjacent cells only spiked by 10°C and never exceeded 90°C. This indicates that Electo TIM effectively isolated the thermal event to the affected cell, preventing thermal propagation to neighboring cells.

Safety Implications

1. Prevention of Cascading Effects: The ability of Electo TIM to contain the thermal event within a single cell is crucial in preventing a cascading failure, which is a common and dangerous scenario in battery packs where one cell’s failure triggers the failure of adjacent cells.
2. Fire Safety: Despite the high temperatures involved in the blast, no fire was observed. This suggests that Electo TIM not only manages heat effectively but also potentially suppresses ignition sources, enhancing the overall safety of the battery pack.

Practical Advantages

1. Ease of Repair: Traditional potting materials used in battery packs can be challenging to repair due to their solid and rigid nature. Electo TIM, on the other hand, offers ease of rework and repair, making maintenance more straightforward and less time-consuming.
2. Cost-Effectiveness: The cost of repair using Electo TIM is competitive. Since the material is mostly reusable, it reduces the long-term maintenance costs compared to traditional potting methods, which often require complete replacement.

Conclusion

The study demonstrates that Electo TIM is a highly effective thermal interface material for Li-ion batteries. It significantly enhances safety by preventing thermal runaway from spreading to adjacent cells, suppresses potential fire risks, and offers practical advantages in terms of ease of repair and cost-effectiveness. These findings suggest that Electo TIM is a promising solution for improving the thermal management and overall safety of Li-ion battery packs.

Future work should focus on long-term testing and the integration of Electo TIM into commercial battery packs to further validate its performance and benefits in real-world applications.