Effects of using fireproof thermal management systems on the lifespan of battery cells

Abstract

The current need, from the point of view of increasing the sustainability of electric vehicles (more and more present in the car market), makes the research in the field to be focused on the analysis of the factors that can lead to an increase electric vehicle batteries' lifespan. Since this is directly related to the temperatures reached during operation and the thermal gradients inside the battery packs, this paper presents the analysis of the cells' lifespan through artificial intelligence methods and techniques, evaluating the influence of the constructive and functional characteristics of two air-based hybrid thermal management systems (CHA - composite material + heat pipe + forced air convection and CTA - composite material + thermoelectric cooler + forced air convection). The construction of the thermal management system is a special and innovative one, being a composite material (epoxy flame-retardant resin and 2 wt% hexagonal boron nitride nanoparticles) chosen as the primary thermal energy dissipation element. The research was carried out experimentally on individual cells and on a battery module (consisting of 12 cylindrical Li-ion 18650 cells), the battery module being discharged at a rate of 3C with the temperatures recorded from 15 locations inside the battery module, which allows assessing the local and global influence of the thermal management systems. Predictions on the lifetime of the cells in the battery module were made using a convolutional neural network and showed that by using the proposed fireproof thermal management systems, the cells’ lifespan increases by 26.9 … 154.4% (depending on the implemented thermal management system and the location of the cell in the battery module).