University of Oxford
About the Project
Research Studentship in Battery Modelling and Performance Testing
Project: The impact of thermal-mechanical-electrochemical coupling on high-rate performance of large Li-ion cells
4-year Industrially funded D.Phil. studentship that includes joining the Faraday Institution PhD Training Programme and an industry internship.
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 reasons, and thermal behaviour may change as a cell 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 as it discharges/charges. 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. These tools have the advantage that they are chemistry- and format-agnostic; we have so far applied them to LFP and NMC pouch cells of various sizes. LIT can be used to estimate physically meaningful parameters such as ionic and electronic conductivities, reaction entropy, and diffusion time in electrodes. By estimating such parameters one can quantify performance limitations in relation to temperature hotspots and ‘fingerprint’ changes over lifetime. This is very important for fast charging (e.g., ensure cell is within safe limits) and cell design (e.g., number of layers and tab size / placement).
This PhD will consider both thermal modelling and 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 the cell’s charge state. Designing stacks that minimize swelling could reduce fatigue loads and extend life. This coupling of mechanical and thermal aspects is unexplored territory: novel physical models need to be created to account for mechanical effects, and feedback loops need to be developed that allow sophisticated coupled electrochemical/ thermal/mechanical models to be parameterized and validated experimentally against high fidelity measurements.
Eligibility
This studentship is fully funded by industry and is 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 a package worth £28,000. The studentship will also include an industrial internship 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 should be addressed 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 graduate application.
Applications will be reviewed on a rolling basis as received, with a final deadline of 1st July 2024.
Start date: October 2024
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