Numerical analysis of heat propagation in a battery pack using a novel technology for triggering thermal runaway. (1st October 2017)

• Record Type: Journal Article
• Authors: Coman, Paul T.; Darcy, Eric C.; Veje, Christian T.; White, Ralph E.
• Is Part Of: Applied energy. Volume 203(2017)
• Page Start: 189
• Page End: 200
• Publication Date: 2017-10-01
• Subjects: Propagation -- Internal short circuit device -- Battery pack -- 18650 -- Safety -- Air gap; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2017.06.033
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: Heat propagation during thermal runaway (TR) in a battery pack with aluminum heat sink was analyzed. TR in the battery pack, triggered by a novel internal short circuit device (ISCD) was modeled. A 2D geometry and model couplings reduce computation time significantly. Small air gaps and mica paper in combination with a thermally conductive matrix increase safety in battery packs. Abstract: This paper presents a numerical model used for analyzing heat propagation as a safety feature in a custom-made battery pack. The pack uses a novel technology consisting of an internal short circuit device implanted in a cell to trigger thermal runaway. The goal of the study is to investigate the importance of wrapping cylindrical battery cells (18650 type) in a thermally and electrically insulating mica sleeve, to fix the cells in a thermally conductive aluminum heat sink. By modeling the full-scale pack using a 2D model and coupling the thermal model with an electrochemical model, good agreement with a 3D model and experimental data was found (less than 6%). The 2D modeling approach also reduces the computation time considerably (from 11 h to 25 min) compared to using a 3D model. The results showed that the air trapped between the cell and the boreholes of the heat sink provides a good insulation which reduces the temperature of the adjacent cells during thermal runaway. At the same time, a highly conductive matrix dissipates the heat throughout its thermal mass, reducing the temperature even further. It was found that for designing a safe battery pack which mitigates thermal runaway propagation, a combination of small insulating layers wrapped around the cells, and a conductive heat sink is beneficial.