How can we anticipate lithium-ion battery swelling and better understand battery ageing? Through the VITESS project, CRITT M2A is developing innovative experimental methods and mechanical models. The aim is to improve battery reliability, optimise testing and accelerate the development of new energy storage systems.

Understanding lithium-ion battery swelling: a major challenge

During charging and discharging cycles, lithium-ion cells undergo volume changes. Indeed, this phenomenon, sometimes referred to as battery “breathing”, causes cells to expand and contract.

However, while these changes are partly reversible, ageing can lead to irreversible swelling. This can affect electrochemical performance, thermal behaviour and battery lifespan.

Therefore, understanding and predicting this phenomenon are essential for developing more reliable and efficient batteries.

This is the challenge addressed by the VITESS project, which aims to develop a mechanical model capable of reproducing cell behaviour and predicting swelling during ageing.

Three test benches developed by CRITT M2A to characterise battery swelling

As part of the VITESS project, CRITT M2A’s teams have designed and manufactured three dedicated test benches. These facilities make it possible to study the mechanical behaviour of lithium-ion cells under different conditions.

1. Calendar ageing under mechanical constraint

Firstly, this test bench enables the study of cell ageing at rest, under a defined initial pressure. It therefore helps characterise the mechanical evolution of batteries independently of charging and discharging cycles.

2. Constrained cycling

In this configuration, the cell is held between two parallel plates. As a result, swelling during cycling generates an increasing force, which is measured using a load cell.

3. Constant-load cycling

Finally, this third test bench is equipped with a spring system, displacement sensors and a load cell. It therefore makes it possible to monitor changes in cell thickness over successive cycles.

Thanks to these three facilities, CRITT M2A collects essential experimental data to analyse lithium-ion battery swelling. These measurements also provide a better understanding of the mechanisms associated with battery ageing.

Combining experimental testing and mechanical battery modelling

One of the main ambitions of the VITESS project is to combine measurements collected from test benches with numerical simulation tools.

To achieve this, experimental data will be used to calibrate a physics-based mechanical model. This model will reproduce lithium-ion cell behaviour and investigate the interactions between swelling, ageing, temperature and electrochemical performance.

This approach, combining physical testing and virtual modelling, has three main objectives:

  • Develop a virtual platform dedicated to battery testing.
  • Reduce the costs associated with experimental testing campaigns.
  • Accelerate the development and time-to-market of new battery systems.

In this way, CRITT M2A contributes to the development of more efficient characterisation methods. This approach also addresses the needs of manufacturers in the electric mobility and energy storage sectors.

A scientific collaboration with the University of Technology of Compiègne

Furthermore, the VITESS project is supported by a collaboration with the University of Technology of Compiègne (UTC), as part of a three-year CIFRE industrial PhD programme.

In this context, CRITT M2A recently welcomed Mostafa Hassan, a PhD researcher who has joined its Research & Development team.

His research focuses on the mechanical modelling of lithium-ion cell swelling. It aims to deepen our understanding of cell behaviour and contribute to the design of more reliable and efficient energy storage systems.

This collaboration also demonstrates CRITT M2A’s commitment to strengthening the links between academic research and industrial applications.

Battery swelling testing expertise available to manufacturers

Beyond its research activities, the expertise and testing facilities developed through the VITESS project are already available to support industrial needs.

Indeed, CRITT M2A supports battery manufacturers and developers in characterising lithium-ion cell swelling. These tests can be performed during calendar ageing, under mechanical constraint or at constant load.

Moreover, thanks to its experimental facilities and modelling expertise, CRITT M2A provides solutions tailored to the development, validation and reliability challenges of battery technologies.

Discover our Research & Development expertise and the solutions developed by our teams to support your innovation projects.

The VITESS project supporting innovation in the Battery Valley

Finally, co-funded by the European Union through the Just Transition Fund (JTF), the VITESS project contributes to the innovation and electrification ecosystem of the Battery Valley.

By combining experimentation, numerical simulation and scientific research, CRITT M2A continues to demonstrate its commitment to developing more efficient, reliable and sustainable battery technologies.

Are you looking to characterise lithium-ion cell swelling or develop new testing methods? Contact the CRITT M2A teams to discuss your needs.