Development of Protection Circuit for EV Batteries

Abstract

Transportation is the key for development of any country in the world. At present we majorly depend on the fuel driven IC engines for transportation. Fuel based vehicles causes severe pollution to the environment so we are moving towards Electric vehicles. But during these days the burning of EV’s is the major setback for the transition from IC engine to Electric motor. So, in this project we designed a circuit to protect the EV battery under abnormal conditions like heating and overcurrent. In order to gain optimum battery performance, the ideal operating temperature range of the Li-ion battery should be 20-45 ℃ . The electric vehicles are powered by lithium-ion battery throughout the world. Compared with other types of fuel vehicles, lithium-ion battery electric vehicles have the great advantages of no vibration, no noise and no pollution. However, Li-ion batteries generate a vast amount of heat when they are operated, resulting in an increase in the temperature of the battery. It is not safe to operate the vehicles when the temperature of the battery is high. The protection circuit for isolating the battery is very important for the safe and reliable operation of the electric vehicle. By using the LM35 sensor and the PIC microcontroller we can detect the temperature of the batteries using relays we can break the circuit under abnormal conditions. Also, the problem of overcurrent needs to be addressed by using the shunt resistors. The purpose of shunt resistor is to measure the current flowing through the circuit. The protection circuit will detect the overcurrent and measure the temperature and if any one parameter increases the maximum value, then microcontroller will indicate the relay to close the circuit. So, with the help of this circuit, we can protect the EV batteries