M/F PhD researcher in “Study of the ageing of Li-ion cells under pulsed fast-charging conditions in automotive applications”

Job Description

Thesis Subject

In the context of electric mobility, fast charging has now become a necessity. However, regardless of the protocol chosen, fast charging causes degradation and limits the service life of batteries. Indeed, during fast charging, mechanical deformations linked to thermal phenomena (physical expansion) or electrochemical insertion/desorption phenomena (chemical expansion) have a significant impact on the battery's lifespan. Furthermore, a lithium deposit may form, which could affect the battery's safety performance. The originality of the thesis lies in a new, innovative protocol based on voltage pulses. The objectives of the thesis will therefore be: (i) To study the degradation mechanisms associated with pulsed fast-charging protocols, (ii) To develop a physical model to better understand the emergence of degradation mechanisms and phenomena.
The tests will not only help to identify the mechanisms of ageing but will also provide data to refine and validate the model that has been developed. Once the model has been validated, the simulations will enable the protocol to be refined with a view to reducing the conditions that lead to degradation.
Work planl:
- State of the art: Fast charging and ageing
State of the art regarding fast-charging protocols (patents and articles).
State of the art regarding the ageing mechanisms of lithium batteries under fast charging.
State of the art in electrochemical battery models
- Definition of test protocols and ageing study
Selection of cells
Definition of ageing and check-up protocols
Test campaign and analysis of ageing
- Modelling
Development of an electrochemical model accounting for the ageing mechanisms identified during fast charging
Validation of the model based on the ageing test campaign
Evaluation of the charging protocol's performance

Your Work Environment

As part of the energy transition and the development of electric mobility, batteries are now one of the solutions on offer. For example, the EU's decision to transition from the current fleet of combustion-engine vehicles to a fleet of electric vehicles by 2035 gives an idea of the expected growth in the battery sector, particularly for lithium-ion batteries. Batteries are also being considered for stationary applications, such as storing renewable energy, which is inherently intermittent. Numerous scientific challenges still need to be overcome in order to improve their reliability and lifespan, and thus reduce their environmental impact. Furthermore, with the growth of electric vehicles, fast charging remains a highly topical issue. The promise of fast charging (taking around 10 to 20 minutes) presents a challenge for every manufacturer, whilst also serving as an undeniable selling point. However, fast charging can cause irreversible damage such as electro-mechanical and chemical degradation or lithium deposition, which reduce the battery's range, lifespan and safety [1–4]. As part of the IBIS project led by Stellantis, SAFT, E2CAD and Sherpa.
The LEPMI laboratory offers a stimulating scientific environment that combines teaching and research. From an experimental perspective, LEPMI's activities rely on the use of a wide range of characterisation tools, including a technical facility dedicated to battery characterisation and cycling. The laboratory also maintains close and privileged relationships with the major facilities at the Grenoble site: ESRF and ILL for the structural characterisation of materials and surfaces, primarily for electrochemical generators (batteries, fuel cells). Finally, simulation tools such as MATLAB and COMSOL are widely used. The thesis, conducted in collaboration with the SATIE laboratory, addresses issues relating to batteries from the material to the model.LEPMI Laboratory, Saint Martin d'Hères, France
http://lepmi.grenoble-inp.fr/

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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