A predictive controller for battery cooling systems to tackle the comfort-safety-efficiency dilemma

The advent of electric vehicles has increased the complexity of air conditioning systems in vehicles which now must maintain the safety and comfort of occupants while ensuring that the high voltage battery temperature is kept within safe limits. This new task is critical due to the influence of the cell and battery pack temperature on the efficiency. Moreover, high temperatures within the battery pack can lead to undesirable effects such as degradation and thermal runaway. Classical solutions to this problem include larger air conditioning components to support worst case scenario conditions where the cooling request from the battery and the cabin happen at the same time. In such conditions, for the safety of the battery, the cooling request is assigned to battery system which may cause discomfort to the passengers due the significant temperature increase in the cabin during such events. The probability of such events happening is certainly dependent on the weather conditions but in areas of the world where high average temperatures are common, it is not unlikely to find such situations. This paper shows a methodology that limits the occurrence of these events by predicting and shifting in time the cooling requests on the air conditioning system. As a result, the maximum load on the cooling system is reduced which may lead to a reduction in the size and weight of the components, with the result of a more efficient vehicle overall.