Modeling of passive thermal management for electric vehicle battery packs with PCM between cells N. Javani a, * , I. Dincer a , G.F. Naterer b , G.L. Rohrauer a a Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe St. North, Oshawa, ON L1H 7K4, Canada b Faculty of Engineering and Applied Science, Memorial University of Newfoundland, 240 Prince Phillip Drive, St. John's, NL A1B 3X5, Canada highlights  To study the cooling effect of the phase change materials in electric vehicles.  To improve current thermal management systems in electric vehicles.  To study the effective properties of PCM-soaked “wet foam” in different volumetric concentrations.  To evaluate the integrated PCM approach for temperature reduction and uniformity. article info Article history: Received 20 March 2014 Accepted 12 July 2014 Available online 22 July 2014 Keywords: Hybrid electric vehicle Li-ion cell Phase change material Battery thermal management abstract A passive thermal management system is examined for an electric vehicle battery pack. Phase change material (PCM) is infused in foam layers separating the lithium-ion (Li-ion) cells. Known operating conditions lead to selecting a suitable PCM for the application, n-octadecane wax. Suitable porous foam for infusion is decided on through experimentation. Finite volume based simulations are conducted to study the thermal behavior of a 4 cell sub-module. The effect of different discharge rates are compared for this sub-module, with and without the PCM's presence. The results show that the maximum tem- perature in the system is decreased up to 7.3 K by replacing dry foam with PCM-soaked “wet foam”. The addition of PCM also makes the temperature distribution more uniform across the cells. The modeling results give indication of the quantity of PCM required, show the influence of the transient melt behavior under dynamic operating conditions, and examine design constraints associated with this approach. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Transportation, as a whole sector, is considered one of the most significant sources of greenhouse gas (GHG) emissions where the root cause stems from the on-road transportation system. Full electric and plug-in hybrids (EVs and PHEVs) are treated as promising solutions to mitigate climate change. These vehicles help improve air quality and decrease the noise in urban regions and facilitate switching toward sustainable energy and transportation systems [1]. Due to the high energy and power density of Li-ion cells, they are viewed as the primary enabling technology within the battery pack. However, by extracting high current, heat generation increases (Ohmic I 2 R losses) which can lead to overheating and lowering the life expectancy of the battery pack. Elevated temperatures augment the growth of the solid electrolyte interface layer over time (SEI), raising internal resistance and contributing to power loss and ca- pacity fade. Ultimately this leads to a reduction in useable cyclic life [2-4]. Though many incremental improvements have been ach- ieved over the years via continued development in lowering in- ternal resistance and increasing the heat tolerance of the constituent materials, nonetheless all vehicles resort to some form of thermal management. The issues tend to be magnified in the smaller battery packs of PHEV's where the discharge current is high relative to the cell's ampere-hour capacity, known as the C rate. In order to establish a scaled-up Li-ion battery pack for electric ve- hicles, an effective thermal management system (TMS) is required to mitigate temperature excursions and lower the peak tempera- ture. These are the two fundamental requirements of any thermal management system [5]. Lacking a proper TMS, coupled with * Corresponding author. E-mail addresses: Nader.Javani@uoit.ca (N. Javani), Ibrahim.Dincer@uoit.ca (I. Dincer), gnaterer@mun.ca (G.F. Naterer), Greg.Rohrauer@uoit.ca (G.L. Rohrauer). Contents lists available at ScienceDirect Applied Thermal Engineering journal homepage: www.elsevier.com/locate/apthermeng http://dx.doi.org/10.1016/j.applthermaleng.2014.07.037 1359-4311/© 2014 Elsevier Ltd. All rights reserved. Applied Thermal Engineering 73 (2014) 305e314