Case Studies in Thermal Engineering 26 (2021) 101029 Available online 24 April 2021 2214-157X/© 2021 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Experimental study on the thermal performance of a battery thermal management system using heat pipes Hussein Mbulu a , Yossapong Laoonual a , Somchai Wongwises a, b, * a Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, Bangmod, Bangkok, Thailand b National Science and Technology Development Agency (NSTDA), Pathum Thani, 12120, Thailand A R T I C L E INFO Keywords: Electric vehicle Battery thermal management system Water cooling Heat pipe ABSTRACT A battery thermal management system (BTMS) plays a signifcant role in an electric vehicle (EV)’s battery pack to avoid the adverse effect of extreme heat being generated during application. A heat pipe-based BTMS is regarded as an alternative technique to maintain an optimum working temperature of the lithium-ion batteries (LIBs) used in EVs. In this study, the heat pipe-based BTMS was designed and experimented under high input power. The battery surrogate was sandwiched with L- and I-shaped heat pipes, and heated at 30, 40, 50 and 60 W. The heat pipes’ condenser sections were cooled by water at 0.0167, 0.0333 and 0.05 kg/s. Findings revealed that the designed heat pipe-based BTMS could give the maximum temperature (T max ) below 55 ◦ C, even at the highest input power, and provide the temperature difference (ΔT) below 5 ◦ C. It exhibited capability to transfer more than 92.18% of the heat generated. Controlling the T max and ΔT within the desirable range demonstrates that the heat pipe-based BTMS is viable and effective at higher heat loads. 1. Introduction Electric vehicles (EVs) have gained much attention as a promising solution against the rising world’s crises, such as global warming [1], the energy crisis, air pollution, etc. The increasing popularity of EVs is strongly assisted by the lithium-ion battery (LIB) tech- nology, which provides clean and dense energy for vehicle propulsion. Many of the attractive features of LIBs include high current, power, energy density [2], prolonged life cycle, no memory effect, and low self-discharge rate [3,4]. Despite the LIBs desirable features that led to its widespread popularity in the market, temperature is sensitive to the LIB’s operation. When the temperature goes beyond a specifed limit, it adversely affects LIB performance, triggers an exothermic reaction and eventually later fre and explosion. The real-world failure of LIBs in different areas of applications have been reported in Chombo and Laoonual [5] and Sun et al. [6]. LIB heating is an inevitable phenomenon; it emerges during operations and should not be underestimated [7]. Thus, an effective and effcient BTMS is crucial to ensure that LIBs are safely operated within the desired temperature and provide an acceptable temperature variation. Additionally, factors such as weight, cost, volume, dependent power and adaptability to EVs are necessary for BTMS’s practical application. In a few decades, researchers have explored various BTMS techniques based on air cooling [8], liquid cooling [9], phase change materials [9], heat pipe cooling [10], nanomaterials and combinations [11,12] to control the heat generation in LIBs. The air cooling method is less complicated, inexpensive and simple to implement. Airfow, battery layout and cooling channel size * Corresponding author. King Mongkut’s University of Technology Thonburi, Bangmod, Bangkok, Thailand. E-mail address: somchai.won@kmutt.ac.th (S. Wongwises). Contents lists available at ScienceDirect Case Studies in Thermal Engineering journal homepage: www.elsevier.com/locate/csite https://doi.org/10.1016/j.csite.2021.101029 Received 30 November 2020; Received in revised form 4 April 2021; Accepted 19 April 2021