Management System Design for Lithium-Based Battery Pack

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Dr. Balázs Gergely György
Department of Electric Power Engineering

The fast development of purely electric power based vehicles in the beginning lagged behind the expansion of internal combustion vehicles in the 20th century. Stricter environmental regulations and rapid consumption of fossil energy sources caused the largest automotive manufacturers to pursue the development of purely electric power driven vehicles to be again as a substitute to internal combustion vehicles. Each prototype includes accumulator feeding that is the weakest part of the vehicles to be developed.

This paper compares the accumulator types most frequently used to feed electric vehicles, considering the pros and cons of each type. Most of them are sensitive to the high level of voltage and temperature rise that raises the need for battery management systems. Management systems are constantly developing and today special circuits are available developed for these systems. The most important task of the monitoring systems is to keep the voltage and temperature limits and give an estimate of the expected lifetime of the accumulators.

A core element of the paper is the characteristics of the charging and discharging of lithium-iron-phosphate accumulators bought for the Formula Student Racing Team Hub Motor Group. The operation of the cells is estimable based on the character curves taken and so setting the parameters of the monitoring system and planning the different parts of the race car gets easier. The paper explains the construction of a monitoring system for the mentioned accumulator type based on the principle of passive balancing, from the first hardware and software plans to the completed plan. In the end the paper explains the structure and operation of the computer-based data collection software prepared for the monitoring system that shows the voltage values of each accumulator cell.


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