Lithium ion batteries represent a well established technology in a range of applications (laptops, mobile phones, etc.) but they are becoming key factors in many other areas were reliability and safety are of paramount importance (e.g. the space and automobile industries). However, a number of drawbacks still raise concerns about their wider use and hamper a more structured introduction in these additional applications.
In particular, the management of heat effects remains a challenge, as an excessive temperature rise can cause reduction of cycle life, battery failures and, above all, may lead to thermal runaway of individual cells or of an entire battery pack, with associated damages to the surrounding people or environment. In the present paper, a simplified model capable of predicting the thermal behaviour of a battery pack refrigerated with a cooling fluid, is presented. It allows to quickly estimating the efficiency of a given cooling system under specific working conditions, and thus identify the range of operation within which a given energy storage system can safely operate.