Limits of Li-Ion Batteries for Public Transportation

Accelerating a 50-ton rather than a 1-ton electric vehicle presents new scientific and engineering challenges. In view of this, our work discusses the power limits of Li-ion batteries as on-board energy storage devices in traction systems used in public transportation. This is based on a thermal analysis of a high power Li-ion battery and an aging/thermal model of it. Included within this process are the following details:

1) General analysis of required heat transfer coefficients.

2) Estimation of internal thermal conductivity along and parallel to electrodes.

3) Use of a thermal network model to calculate internal temperature.

Based on this approach, routes to develop higher power Li-ion batteries are discussed based on our current understanding of the electrochemical and heat transfer limitations. A proposal on future electrochemical devices, designed especially for public transportation, is also discussed in detail.