Experimental investigation on thermal management of electric vehicle battery with heat pipe Zhonghao Rao a , Shuangfeng Wang a,⇑ , Maochun Wu a , Zirong Lin a , Fuhuo Li b a Key Laboratory of Enhanced Heat Transfer and Energy Conservation of the Ministry of Education, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China b Sanmenxia SuDa Communication Energy Saving Technology Corporation Ltd., Sanmenxia 472000, China article info Article history: Received 11 May 2012 Received in revised form 25 July 2012 Accepted 17 August 2012 Available online 11 October 2012 Keywords: Thermal management Power battery Heat pipe Electric vehicle Temperature difference abstract In order to increase the cycle time of power batteries and decrease the overall cost of electric vehicles, the thermal management system equipped with heat pipes was designed according to the heat generated character of power batteries. The experimental result showed that the maximum temperature could be controlled below 50 °C when the heat generation rate was lower than 50 W. Coupled with the desired temperature difference, the heat generation rate should not exceed 30 W. The maximum temperature and temperature difference are kept within desired rang under unsteady operating conditions and cycle testing conditions. Applying heat pipes based power batteries thermal management is an effective method for energy saving in electric vehicles. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction On account of the advantages such as energy saving and zero- emissions, electric vehicles have received more and more attention in recent years. The developing electric vehicles market demands high specific power and high specific energy density batteries for the purpose of meeting the operational needs of electric vehicles [1]. Various power batteries including lead–acid [2], nickel metal hydride (Ni-MH) [3] and lithium-ion (Li-ion) [4] are available for electric vehicles applications. In general, the performance of power batteries directly affects the performance of electric vehicles [5]. However, the heat generated from the power battery during charge/discharge can lead to safety risks such as overheating, com- bustion, and explosion of the battery [6]. Ramadass et al. [7] did a capacity fade analysis for Li-ion battery and elucidated that 31% and 36% of the initial capacity were lost after 800 charge–discharge cycles which were operated at 25 °C and 45 °C, respectively; while the capacity fades were more than 60% after 600 cycles at 50 °C and 70% after 500 cycles at 55 °C. Li and Su [8] also pointed out that the cycle life of lithium-ion battery is 3323 cycles at 45 °C, but 1037 cycles at 60 °C. Therefore, thermal safety is a key issue for the re- search and development of power battery within electric vehicles. For the purpose of increasing the cycle life of power battery, and decreasing the cost of whole electric vehicles, an effective thermal management system for battery module/pack is crucial. There are several battery thermal management strategies which can be summarized as active and passive systems [9], or air [10], liquid [11] and phase change material (PCM) [12] based systems and combination of them. A detailed review of battery thermal management can be seen in our previous work Ref. [13]. Each method has its advantages and it can be used under the specific condition. The active battery thermal management system such as air forced convection cooling and liquid cooling in- creases the total energy consumption of the electric vehicles. Hence, the passive battery thermal management system without parasitic power consumption will be more suitable for commer- cialize of electric vehicles. We have investigated the thermal man- agement performance of aging commercial rectangular LiFePO 4 power batteries using PCM [14]. Selman and Al-Hallaj, who first demonstrated the PCM based battery thermal management, have presented many results by experimental and simulated methods [15–18]. Duan and Naterer [19] also provided some new experi- mental data for the effective thermal design of PCM based battery thermal management system. The previous works showed that PCM for power battery thermal management was successful. Most of these works have pointed out that the thermal conductivity of traditional PCMs were lower that limited them usage for battery thermal management. In this context, it is necessary to enhance the heat transfer of PCM or to consider new passive battery ther- mal management systems. 0196-8904/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.enconman.2012.08.014 ⇑ Corresponding author. Tel.: +86 20 22236929. E-mail address: sfwang@scut.edu.cn (S. Wang). Energy Conversion and Management 65 (2013) 92–97 Contents lists available at SciVerse ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman