Research on lithium ion battery applications in vehicles

• Main Author: Huang, Ke
• Other Authors: Zhao Jiyun
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/60512
• Institution: Nanyang Technological University

Much attention has been paid on batteries recent years because of their wide application in portable electronic devices as well as vehicles, ships and aircrafts. Among all kinds of batteries, lithium-ion battery (LIB) plays an essential role in marketplace due to their high capacity, high efficiency, long life and low self-discharge rate，which make LIB become the perfect power supply of the electric vehicle. However, LIB has problems of poor safety characteristics caused by high heat generation and the temperature rise during charge and discharge. The high temperature affects the performance, reliability and lifespan of the battery and may cause serious safety hazards such as thermal runaway, even ignition. The safety problem and poor working properties at high temperature makes thermal behavior of LIB one of the most important issues in studying an improving the properties of it. If we want to make it possible for electric vehicle, these problems of LIB must be solved. In this report, the LIB temperature prediction model is proposed. The one-dimensional thermal/electrochemical model is based on the mathematical calculation. This model is integrated with actions of electrode reaction, joule heating, heat conduction and heat convection is developed to predicted the internal temperature of a battery cell in real time by relying on only the non-intrusive measurements of cell surface temperature and electrical quantities. The modeling approach started from the microscopic electrochemical reaction in the battery interior and ended up with the macro distribution of temperature throughout the cell, with the potential of application in BMS. And an intelligent battery cooling system is designed to improve the safety characteristic of battery/battery pack. This can help LIB maintain good working performance in electric vehicle. There are mainly four parts included in the intelligent battery cooling system, battery pack, temperature measurement circuit, DC-DC boost converter and a cooling device. When the temperature of battery pack rise to warning level, the output voltage of temperature measurement circuit will rise to a critical value under the amplification of boost converter, it can drive the cooling device (electric fan, etc.) and cool down the battery pack. DC-DC converter plays an important role in several parts of BMS. Conclusions are given at the end of this report and a discussion on future works is also presented. The proposed future work includes the optimization and combination of single cell temperature model, study on temperature prediction of battery pack, the research about mutual temperature effect of cells and the setting up of intelligent battery cooling system.