Tell us about your research
My group and I explore batteries from an engineering perspective. We’re mostly interested in analysing and improving the performance of commercially-available or near-commercial batteries, rather than developing new chemistries. We model and measure how batteries behave in specific applications and investigate characteristics such as how quickly they degrade or how hot they get, to develop lifetime models, charging algorithms or thermal management systems to optimise their performance. We look at questions such as: does a battery degrade faster at high states of charge, and how does this vary across different battery chemistries and manufacturers?
How do you describe why your work is important to non-specialists?
We are trying to squeeze the most out of batteries, which are still relatively expensive and made with valuable and limited materials. For example, within the Faraday Institution’s Multi-scale Modelling project, we are developing improved compact battery simulation models to increase accuracy of state of charge, temperature, and life estimation. We’re especially interested in generalising insights by working on large datasets to ensure that our findings apply widely. It is vital to understand in these kinds of applications if the system is functioning optimally. For example, is the thermal management system unnecessarily wasting energy? Is the control system working correctly? How much battery life is used up during charge and discharge cycles? We’re looking at these system integration questions to understand how to improve the operational conditions.
How did you get into battery research?
I have been interested in clean energy and sustainability since I was an undergraduate. After studying electrical engineering at the University of Cambridge and then working in industry for a few years, I decided I wanted to go into research. So, I did a PhD at Imperial College London on electric motors that are relevant to some types of wind turbines and hydropower systems. After the PhD I chose to focus on batteries. Ten years ago, there was a lot of engineering research still to be done with batteries and a lot that we didn’t know – some hybrid cars were only using 50% of their battery capacity because of concerns about degradation. My interest in trying to understand these issues and make better use of batteries brought me to the University of Oxford, and I have been building up my team here ever since.
What is a highlight of your career to date or the aspect that gives you greatest job satisfaction?
One highlight that comes to mind is our spin-out company Brill Power, a company developing intelligent battery management and control technology to increase the lifetime and reliability of lithium-ion battery packs. I am immensely proud of what the team at Brill Power has achieved. It was named Top Battery Company 2022 at Energy Tech Challengers and raised $10.5 million in funding in July 2022. On the personal side, I’m very proud that some of my former PhD students lead the company. I take immense satisfaction in interacting with great people to do research and seeing how students develop and learn in my group, and have gone on to do exciting things. As a senior academic, I recognise my role in providing training as well as research. With that in mind, I try to create a group atmosphere that is collaborative, inclusive, and relaxed so people enjoy coming to work and have the freedom to be creative.
What accomplishment are you most proud of?
Recently, we developed an algorithm that diagnoses battery health with 15-20% more accuracy than current approaches. We published our results in Joule, and filed a patent on it last year. Capacity fade or resistance increase is impossible to measure directly, so it must be inferred through careful lab tests or models. It’s challenging to do this for real applications. We had to measure battery health from live, operational data. Our method could help millions of people have better access to electricity from off-grid systems, as it allows battery performance to be optimised and batteries to be quickly replaced when they fail. The seed idea for this project began ten years ago when I was a PhD student at Imperial and I met a group of enthusiastic undergraduates who later founded the energy company Bboxx Ltd, which provided us with the data we needed. As explained in this article, we analysed measurements from 1,000+ batteries running for three to five years and ended up with six hundred million rows of data. We do a lot of work with companies like Bboxx, focussing on industry-relevant problems, and the sweet spot is finding an industry-relevant issue that’s also scientifically exciting. This is a nice example of that.
What opportunities has being part of the Faraday Institution opened up for you?
The Faraday Institution has brought people together from a range of different disciplines in an exciting new way, allowing researchers to share expertise and gain exposure. It also provides a focal point for UK battery work and can point companies needing expertise in the right direction. Personally I’ve enjoyed the breadth of different Faraday Institution projects we have been part of, from electrochemical modelling to techno-economic studies.
What are the biggest challenges you have overcome during your career and how have you gone about doing so?
My PhD was challenging because it took a complicated route. My initial supervisor left the university halfway through, and I found myself seriously wondering how I would be able to finish everything. I had to bin some of my early work and pick up new stuff from scratch. It felt awful at the time, but in hindsight I gained many key skills through the experience. It taught me how to break down an open question, plan experimental research, and have the confidence to carry it out.
What advice would you have liked to have given your younger self starting out on your career?
I would tell myself to think carefully about what a PhD is and exercise due diligence before choosing a research group and topic. I’d also tell myself to embrace every opportunity, which is something I’m much better at doing now. I’m incredibly thankful to be where I am now, but I’d remind myself that a lot of success is built on luck, so don’t beat yourself up if things don’t always work out as you expect.
What are your career aspirations?
Usually, when people are asked about their career aspirations, they reply on the scale of decades, but I’m conscious of accelerating climate change and wonder how I can have the most impact in the shortest time. That’s hard to address in academia, which tends to work over long timescales. For example, early battery research began in the 1970s, and the commercialisation of lithium-ion batteries was in the 1990s. Twenty years from now will be too late to start making impacts on climate change. So, I’m increasingly thinking about how we can measure our immediate impact – if we develop a new algorithm that can control a battery, how can I get that into the most impactful applications as quickly as possible? I’m also interested in broadening my research. The convergence of energy, machine learning and data is exciting, and I’m exploring adjacent topics like solar power.
Finally, I’ve been considering how we, as academics, can show climate-aware leadership in our day-to-day activities. For example, I’m organising a conference in Oxford on battery modelling, which I’m keen to do as a hybrid event to avoid unnecessary flights. It’s a small example, but considering our position to influence others, these choices are important.
What is your favourite battery-related fact?
We wouldn’t have batteries today if it weren’t for frogs. In the 1700s, Luigi Galvani was investigating how frog legs contracted when touched with a brass wire and steel scalpel. He thought these contractions were due to “animal electricity”, but later experiments by Alessandro Volta revealed that two rods of different metals in an acidic bath could produce electric potential independent of an animal. He developed these early experiments to invent the first battery in 1800.
If people want to find out more about your research, where would you point them to?
The Battery Intelligence Lab group website provides contains lots of information about our research. This article explains how we analysed the data we got from Bboxx.
In 2021, I gave a Lubbock lecture hosted by the Department of Engineering Science on how batteries are charging ahead, and gave a brief overview of our work.
Published November 2022.
About the author: Cara Burke is the Faraday Institution’s Science Communications Intern in the summer of 2022. She has just completed her BSc Biological Sciences degree at Imperial College London and is pursuing a career in science communications.