Study on the thermal interaction and heat dissipation of cylindrical Lithium-Ion Battery cells

Abstract

Cylindrical Lithium-Ion Batteries have been widely used as power source for electric and hybrid vehicles because of their compact size and high power density. The battery pack is commonly consisted by hundreds of cylindrical Lithium-Ion battery cells in several strings. Because the distance among battery cells is only a few millimeters, the thermal status of battery would directly influent the current efficiency and battery life. In order to maintain proper function of the battery pack, the heat dissipation around battery cells should be deeply investigated and well controlled. This question is undeniably important and which has gained increasing attentions. Researchers have developed some models of the transient temperature distribution in Lithium-Ion battery during the discharge cycle and the thermal management on various kinds of battery packs has been studied. However, because of the compacted and complicated structure inside battery pack, the full thermal status and detail distributions are difficult to be revealed in the same time. In this work, three-dimensional simulation methods have been used to solve the above questions on the combination of several cylindrical Lithium-Ion battery cells. Existing heat generation models in Lithium-Ion battery is defined as the thermal boundary conditions. The flow and convection on the spacing has been studied. The transient thermal interactions and convections among adjacent battery cells have been investigated to explore the influences by spacing and transient heat release rules. The achieved results can be used as critical reference for designing the structures of battery pack and planning the cooling strategies.