PhD Studentship: Research Studentship in Battery Modelling and Performance Testing

4-year Industrially funded D.Phil. studentship that includes joining the Faraday Institution PhD Training Programme and an industry internship.

Project: The impact of thermal-mechanical-electrochemical coupling on high-rate performance of large Li-ion cells

Application: Solving challenges in optimising battery performance for automotive applications in the quest to electrify the transport system and create a more sustainable future.

Supervisors: Professors Charles Monroe and David Howey

Li-ion cells generate substantial heat during operation. Predictive modelling of temperature is important for safety and performance, and thermal behaviour may change as a battery ages. In large prismatic pouch cells, coupling of the in-plane distributions of temperature and current density has been shown to cause thermal instability, and if heat-transfer rates from surfaces are low, the temperature within a cell can increase significantly during use. In this work we will build from our existing suite of lock-in thermography (LIT) tools, which have paved the way for ‘three-dimensional’ thermal profile estimation with electrochemical-thermal models. LIT can be used to estimate physically meaningful parameters such as ionic and electronic conductivities, reaction entropy, and diffusion time in electrodes. This allows quantification of performance limitations, and ‘fingerprinting’ of changes over lifetime; both are important for fast charging and cell design.

This PhD will also consider battery swelling, which remains open from a theoretical standpoint. Previous work has established how changes in battery shape are observable on the cell level (the casing swells by as much as 1%). In defiance of conventional wisdom, experiments show that swelling depends on local temperature—which gives rise to thermal expansion—as strongly as it depends on state of charge. Designing packs that minimize swelling could reduce fatigue loads and extend life. This coupling of mechanical and thermal aspects is unexplored: novel physical models need to be created to account for mechanical effects, and feedback loops need to be developed that allow sophisticated coupled models to be parameterized and validated experimentally against high-fidelity measurements.

Eligibility

This studentship is fully funded by industry and open to UK Home students (full award – home fees plus enhanced stipend).

Award Value

Course fees are covered at the level set for home students c. £9,500 p.a. The stipend (tax-free maintenance grant) is c. £23,050 p.a. for the first year, and at least this amount for a further three years. The candidate will also join the Faraday Institution’s PhD Training Programme , which is worth £28,000, and undertake an industry placement.

Candidate Requirements

Prospective candidates will be scored according to how well they meet the following criteria:

• A first-class honours degree in Engineering, Physics or Materials Science
• Excellent English written and spoken communication skills

The following skills are desirable but not essential:

• Ability to program in Matlab
• Experimental experience

Application Procedure

Informal enquiries are encouraged and to Profs David Howey and Charles Monroe ({david.howey, charles.monroe}@eng.ox.ac.uk).

Candidates must submit a graduate application form and are expected to meet the graduate admissions criteria. Details are available on the course page of the University website .

Please quote 24ENGEE_DH in all correspondence and in your application.

Applications will be reviewed on a rolling basis as received, with a final deadline of 1st July 2024.

Start date: October 2024