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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-469-4

ISBN Online: 978-1-56700-470-0

Second Thermal and Fluids Engineering Conference
April, 2-5, 2017, Las Vegas, NV, USA

Li-ion Battery Thermal Management – Air vs. Liquid Cooling

Get access (open in a dialog) pages 1759-1772
DOI: 10.1615/TFEC2017.fna.017297

Abstract

The Li-ion battery operation life is strongly dependent on the operating temperature and the temperature variation that occurs within each individual cell. The operating temperatures for optimal battery performance and hence, longer battery life occur in a very narrow temperature bandwidth. The heat generated by the battery cells has to be removed efficiently in order to maintain the operating temperature within the required limits. In general, the cooling of a battery pack is achieved by using liquid or air. In order to evaluate various cooling concepts and compare their cooling performances, it is required to understand the basic flow and heat transfer quantities associated with the cooling performance. The current Chevy Volt battery pack utilizes liquid as the cooling agent. Liquid-cooling is very effective in removing large amounts of heat with relatively low flow rates. On the other hand, air-cooling is simpler, lighter and easier to maintain. However, in order to achieve similar cooling performance, a much higher volumetric air flow rate is required due to its lower heat capacity. The main objective of this paper is to describe the fundamental differences between air-cooling and liquid-cooling applications in terms of basic flow and heat transfer parameters, which, includes QITD (Inlet Temperature Difference). Based on the initial assessment for the Chevy Volt battery pack cooling, liquid-cooling has definite advantage compared to air-cooling in terms of heat transfer coefficient and cooling capacity. In this paper, we also assess the design limits for air-cooling systems based on the volumetric flow rate and the heat transfer coefficient. The present study will help to assess the cooling requirements between air and liquid and thus the requirements for the coolant flow rate and the heat transfer coefficient.