Actively controlled thermal management of prismatic Li-ion cells under elevated temperatures

This paper reports the experimental study of the active control of the thermal management for prismatic lithium ion (Li-ion) batteries under an elevated thermal environment with temperature above 40 °C. To defray the cost of performing experimental study under such conditions while obtaining meaningful data for a multi-cell battery pack with practical relevance, this study developed an experimental setup using a combination of four real Li-ion cells and 12 dummy cells. The dummy cells were fabricated to have the same geometry as the real cells and embedded with controllable heating elements to simulate, respectively, the aerodynamic and thermal behavior of a multi-cell pack. This experimental setup was then placed inside a wind tunnel so actively controlled cooling tests can be performed under well-controlled flow conditions. During the tests, heating power up to 6 × 104 W/m3 was generated by the dummy cells, creating and the maximum environment temperature above 40 °C. The major observations obtained from these experiments were twofold. First, besides reducing the experimental cost, the combination of real and dummy cells also offers flexibility to obtain experimental data of a large pack under a variety of conditions for model comparison. Second, a simple on-and-off control strategy was demonstrated to effectively reduce the parasitic power consumption of the cooling systems under the evaluated environmental temperature, even when the Li-ion cells were under dynamic load.