PhD position - Study and simulation of the behaviour of lithium-ion cell protection elements in short-circuit or overcurrent conditions at pack level.

OPPORTUNITY DETAILS

Total reward

0 $

State University

CEA Tech

Area

Western Europe

Host Country

France

Deadline

31 Oct 2021

Study level

Doctoral Degree

Opportunity type

PhD

Specialities

Physics , Chemistry

Opportunity funding

Not funding

Eligible Countries

This opportunity is destined for all countries

Eligible Region

All Regions

SL-DRT-21-0839

RESEARCH FIELD

Energy efficiency for smart buildings, electrical mobility and industrial processes

ABSTRACT

The safety of Li-ion batteries is a major issue in the development of these technologies. In order to best address this issue and to be able to design safe battery systems, the main dreaded events are classified and one or more safety elements are defined for each one.The internal cell faults leading to a thermal runaway are mainly managed by the venting(s) and design elements that prevent the first fault from propagating. Numerous works aim at improving our understanding of these phenomena. External faults, on the other hand, generally have the specificity of being applied at the same time on all or a large part of the battery pack. If the protections are not adapted, badly positioned or badly designed, the consequences can be dramatic. Voltage overloads or over-discharges are managed at the first level by the BMS, while short-circuits/overcurrents are managed by fuses or contactors of the pack or by internal cell protections such as CID or PTC (Current Interrupt Device or Positive Temperature Coefficient).In this thesis we will focus on external faults like short circuits or over currents applied on all or part of the battery pack, thus concerning a large number of cells. If the short circuit occurs on the load, then the battery pack will simply be protected by the fuse, but if this short circuit for an unknown reason (crash, conductive dust, electrolyte leakage, double insulation fault, ...) occurs on a current path not protected by a fuse, then the internal protections of the cells will be solicited. To be sure that they will operate correctly, it is necessary to have correctly characterized them in the different fault modes.The thesis work will be based on three axes of work :- A first experimental axis will focus on the characterization of the cells and their protection in fault conditions.- A second axis will aim to set up cell models before and after faults- Finally, the last axis will aim at building battery pack models allowing to play scenarios according to random fault conditions (impedance and short circuit position).