The Fast Charge System For Lead-acid Traction Batteries

The design is for special lead-acid battery which is mainly used for the electric traction vehicle and other materials loader equipments in coal mine. The cost of this kind of battery has been an inevitability part of coal mine cost for its used widely. Therefore, prolonging the battery life, shortening the recharge time, and reducing loss will make a very important effect on decreasing the cost and increasing the economic benefits for mine coal. Now, the charge methods in coal mine always are conventional ways like constant current and constant voltage with current limitation which do not follow the physical and chemistry rules of the battery, most part of always exist the phenomenon of overcharged and gas-generation, then make the battery 's life shorter and reduce the efficiency of the whole charge process.To these conditions, the author studied the electrochemistry mechanism of lead-acid battery and kinds of polarizations which affect charge, and discover that the maximal acceptable current of battery depends on the amount of active material on the battery plates and the reactive environment. However, the maximal acceptable current of battery can be increased and restrain the polarizations and the last temperature-rise by adding reverse pulse discharge at the proper time in the whole process of charge.In order to integrate theory into practice, the author studied the relation of voltage and the charged capability of battery in the charge process. According to the relation, the author combined the velocity of voltage change and temperature-rise of battery to decide whether to discharge for depolarization, and then increase the current acceptable ratio of battery as much as possible.This design chooses ARM as core of the whole control system, the two units IGBT module as power switch composing Buck-Boost circuit and also includes drive circuit, voltage /current sampling circuit, temperature detecting circuit, LCD display unit and kinds of protect circuit and so on. The design can realizes fast charge and constant current charge and the display of charging current, voltage, charged capacity and reporting data etc.The experiment datas shows that the design can shorten the charging time greatly and inhibit the temperature-rise in the late stage.