Development of a system for characterizing the safety devices of Li-ion batteries

IFP Energies nouvelles (IFPEN) est un acteur majeur de la recherche et de la formation dans les domaines de l’énergie, du transport et de l’environnement. De la recherche à l’industrie, l’innovation technologique est au cœur de son action, articulée autour de quatre priorités stratégiques : CLIMAT, ENVIRONNEMENT ET ÉCONOMIE CIRCULAIRE, ÉNERGIES RENOUVELABLES, MOBILITÉ DURABLE et HYDROCARBURES RESPONSABLES.

L’engagement d’IFPEN en faveur d’un mix énergétique durable se traduit par des actions visant :

• à gagner en efficacité énergétique ;
• à réduire les émissions de CO2 et de polluants ;
• à améliorer l’empreinte environnementale de l’industrie et des transports ;

tout en répondant à la demande mondiale en mobilité, en énergie et en produits pour la chimie.

Dans cet objectif, IFPEN développe des solutions permettant, d’une part, d’utiliser des sources d’énergie alternatives et, d’autre part, d’améliorer les technologies existantes liées à l’exploitation des énergies fossiles.

Development of a system for characterizing the safety devices of Li-ion batteries

Li-ion batteries are the technology shared by all automakers to provide the energy storage required for the deployment of electrified vehicles. However, Li-ion batteries can be the source of incidents with dramatic consequences. These incidents can have various origins, but are grouped together under the term thermal runaway. Thermal runaway is currently one of the main obstacles to the development of electric mobility and has a major impact on battery design and performance.

In this context, IFPEN is developing experimental tools to qualify the runaway of a Li-ion cell. These tools are intended to fill a gap identified in the literature by providing the data needed to develop models of thermal runaway initiation.

The most recent battery technologies are equipped with a safety vent which intervenes in the event of an increase in the battery's internal pressure. While the safety vent preserves the structural integrity of the battery, the characteristics of the jets emitted have a fundamental impact on the evolution of the runaway and its propagation to other battery pack components.

The aim of this internship is to develop a methodology for characterizing the flow in safety vents. With the help of IFPEN laboratory staff, the candidate will participate in setting up an experimental device to characterize the gas jet emitted by safety vents under controlled conditions. This will involve separating the vent from its original component, coupling it to a pressure-controlled gas source (N2) and installing sensors to measure flow. The jet formed at the vent outlet will also need to be characterized to understand its shape and orientation, using high-speed imaging techniques.

In this context, the proposed internship will be structured in four phases: 

1. Literature review phase to learn more about thermal runaway issues
2. Initial experimental phase to define a protocol for the separation of the safety vent from the study battery and coupling with the high-pressure N₂
3. Installation of a flow measurement system coupled with optical diagnostics for jet characterization
4. Exploitation and analysis of results and validation of methodology.

The candidate will work in the optical diagnostics laboratory, receiving training and assistance in setting up diagnostics (R108) and interacting with the battery team (R173).

Profile required:

Master 2 (Bac+5) or final year of engineering school motivated to carry out research and development work.

• Notions of optics, Li-ion battery operation and interest for measurement and experimentation.
• Programming and signal processing tools (Matlab and/or Python, etc.)
• Ability to work as part of a team and communicate about your work.

Duration and period of internship: 6 months between January and September 2024

Practical information: The internship will take place at IFP Energies nouvelles in Rueil-Malmaison. A monthly allowance will be paid to the trainee (if not otherwise remunerated).

Interested? Send a cover letter and CV !