Applicability of new Lithium-ion battery technologies to light electric vehicle use : battery cell level evaluation on vehicle performance

Abstract

The development of drive batteries for electric motorcycles is a continuing effort at vehicle manufacturers. New lithium-ion and other cell technologies are emerging and according to the cell suppliers’ marketing materials, theoretically they will provide significant improvement opportunities. Vehicle manufacturers need to be able to select the best cells to suit their application to develop and build their drive batteries with. The various test protocols, standards and methods provided and mandated via international and national regulations and legislation leave an important question unanswered: How would a specific vehicle perform with a specific battery cell? A vehicle manufacturer needs to understand the answer to the proposed question. They also need to be able to simulate the operation of different cells in different situations and evaluate how a user would be affected by specific characteristics of battery behaviour, such as charge times and range.

This thesis develops a theoretical test method and a model for evaluating the performance of a specific vehicle combined with a battery constructed from specific cells. The technical details of the vehicle and the battery cell type can be adjusted and inserted into the model. The model is a mathematical model based on vehicle dynamics. After constructing the test model, the application of the created model to actual testing of battery cells is carried out. The cell tests are carried out in a Maccor test system in a battery testing laboratory, using the charge-discharge-charge-discharge test method developed for this purpose. The resulting data is analysed using graphical methods. The analysis results provide answers to the proposed research question and can be implemented when selecting cell types for further research. The thesis was commissioned by a vehicle manufacturer who wishes to remain unnamed.