Module design and fault diagnosis in electric vehicle batteries

By Gregory J. Offer, Vladimir Yufit, David A. Howey, Billy Wu, Nigel P. Brandon. 2012

194 citations recorded by the source corpus.

Abstract Systems integration issues, such as electrical and thermal design and management of full battery packs – often containing hundreds of cells – have been rarely explored in the academic literature. In this paper we discuss the design and construction of a 9 kWh battery pack for a motorsports application. The pack contained 504 lithium cells arranged into 2 sidepods, each containing 3 modules, with each module in a 12P7S configuration. This paper focuses particularly on testing the full battery pack and diagnosing subsequent problems related to cells being connected in parallel. We demonstrate how a full vehicle test can be used to identify malfunctioning strings of cells for further investigation. After individual cell testing it was concluded that a single high inter-cell contact resistance was causing currents to flow unevenly within the pack, leading to cells being unequally worked. This is supported by a Matlab/Simulink model of one battery module, including contact resistances. Over time the unequal current flowing through cells can lead to significant differences in cells’ state of charge and open circuit voltages, large currents flowing between cells even when the load is disconnected, cells discharging and aging more quickly than others, and jeopardise capacity and lifetime of the pack.

Subfields: Automotive Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/6a7fef3c9c581b6c5895e7372d6231b4c001022e

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Automotive Engineering

1. Widanalage Dhammika Widanage
2. James Marco
3. Xinhua Liu
4. Shichun Yang
5. Thomas Bruen
6. Billy Wu

In Electrical and Electronic Engineering

1. Widanalage Dhammika Widanage
2. James Marco
3. Xinhua Liu
4. Shichun Yang
5. Thomas Bruen
6. C. Orendorff
7. Billy Wu

Citations in the corpus

• Modelling and experimental evaluation of parallel connected lithium ion cells for an electric vehicle battery system (2016, methodology): “used a simple cell model in Simscape for analysing the effect of poor connection resistance between parallel cells [15].”
• Failure propagation in multi-cell lithium ion batteries (2015, background): “[17] showed that cells nearest the load point can discharge at a greater rate due reduced resistance between the cells and the load point, leading to increased heating of cells near the load point.”
• Battery digital twins: Perspectives on the fusion of models, data and artificial intelligence for smart battery management systems (2020, methodology): “By using this approach, faulty interconnection resistances in a 12P7S pack could be identified in the work by Offer et al. [32] .”