Evaluation of the thermal impact from battery packs from electrical vehicles in underground mining environment

Abstract

One of the main aspects which governs the size of ventilation facilities in underground mines is the amount of heat load generated in the underground environment. This heat load comes from many different sources, one of which is the heat contributed by underground diesel machinery operation. One strategy to mitigate the heat and other emissions from such equipment is to substitute these units to similar performance, but more thermally efficient, electric machinery. This study presents a heat load evaluation of the Lithium-iron Phosphate battery system used in a prototype electric mining vehicle. The set of equations which governs the heat generation from these devices have been developed by previous researchers and is used in this thesis to calculate the heat generation and loss. However, in the mining industry, the current methodology for heat load calculation from electric vehicles (EVs) is usually based on the rated power or on a simple power loss equation. This strategy might lead to incorrect estimations of the heat load from this type of machinery. Experimental and simulation work has been conducted as a means to evaluate the heat flux from the Lithium-iron Phosphate battery system. The battery was tested through charging and discharging it under different levels of current within the 10% to 90% range of its maximum capacity. The test was performed firstly with a single cell and then with a module. Furthermore, the battery system was set in operation under different environment temperature settings. These current and temperature levels represent the range of possible conditions in which the prototype will face in service. Through the estimation of the heat released from the other main electrical components in the vehicle, it was possible to calculate the heat impact of these units in the surrounding environment.