Simon O'Kane, Imperial College London
Simon O’Kane, research associate at Imperial College London is developing the open-source Python software PyBaMM to model how batteries degrade with usage and time
Tell us about your research
I model how batteries degrade with usage and over time as a computer modeller on the Multi-Scale Modelling project. I am a developer for the open-source python software PyBaMM (Python Battery Mathematical Modelling), supported by the Faraday Institution and NumFOCUS. PyBaMM solves physics-based electrochemical models using state-of-the-art automatic differentiation and numerical solvers. Anyone with any level of programming and battery knowledge can use PyBaMM. It can be used to test batteries by inputting certain parameters and quickly and cheaply answering questions like, what if they charge or discharge faster? What if we add thermal effects? What if we add a degradation mechanism to it? Or speed up lithium diffusion?
I am adding additional physical processes to the program. I have already added lithium metal plating, which is one of the ways batteries can degrade. I have recently added another degradation mechanism: unwanted side reactions that occur on cracks in the material.
How do you describe why your work is important to non-specialists?
We don’t fully know how to best treat batteries to make them last longer. We’re still unsure why some batteries fail gradually, whereas others will suddenly lose capacity. A variety of degradation mechanisms are known to exist, including solid-electrolyte interphase (SEI) growth, lithium metal plating, mechanical cracking, solvent consumption, acid dissolution and oxygen release. Different modelling papers have proposed different mechanisms as the cause of sudden failure. We now believe all these mechanisms can result in sudden failure. Which one is activated first depends on the design of the battery and how you use it.
Battery models can be used to design products on a computer and predict their performance, considering the properties of the materials, components and cells and impacts on functionality across the pack lifecycle. PyBaMM allows users to contribute their research ideas and use them together with research that already exists, so they can build off previous knowledge. This saves time and money as there is reduced need to use expensive prototypes or long duration experiments. We can use modelling to design better batteries as well as providing better guidance on how battery-powered devices should be used.
How did you get into battery research?
I did physics as an undergraduate at the University of Bath, where I lived for ten years before moving to London. My master’s project was on solar cells. I stayed in Bath for my PhD in light-emitting diodes and then for my postdoc where I got back into solar cells. But solar cell research was hard to stay in because typically, there is more focus on making them rather than modelling them. Someone I worked closely with moved into batteries, and I took inspiration from them and applied to a battery-related position at the University of Warwick. I didn’t get it, but their informal feedback was invaluable for me getting my current position at Imperial College London. I personally know many academics who moved into batteries using the transferable skills they got from other areas of expertise.
What is a highlight of your career to date or the aspect that gives you greatest job satisfaction?
I love the balance between doing the science and having my results serve a practical purpose. The greatest job satisfaction is the feeling of success from having solved a challenging problem.
What accomplishments are you most proud of?
My most significant accomplishments have involved helping others. I am very proud of my contribution to PyBaMM because it will be used by people worldwide and have a big impact. It already has over 300 users from across the globe, and the PyBaMM development team were awarded the Faraday Institution 2021 Collaboration Award for our wide-reaching collaboration of over 40 contributors from around the world.
We took on new staff post-pandemic, many of whom came from other areas of expertise and knew nothing about batteries. Teaching them was a rewarding experience and accomplishment.
What is the biggest challenge you have overcome in your career and how have you gone about doing so?
In the past, I have had to cope with systematic bullying, which seriously chipped away at my self-esteem. I didn’t seek any support at the time – it’s weird, but it wasn’t until a long time after I was out of that environment that I realised what had happened and how harmful it was. It took me a long time to move on from that situation. It affected my mental health both at the time and afterwards. When I was unemployed for a while, the Pokémon Go app was the only thing that could get me out of the house! I remember telling a friend about it, and she said something that stuck with me: “sometimes we need our silly little things in our silly little lives, and that’s okay.”
I think universities and institutions need to actively respond to these situations when they occur.
What opportunities has being part of the Faraday Institution opened up for you?
The Faraday Institution funding gave me another chance. It is tough to get a job after being out of work for a while – employers often assume the worst, and even if they don’t, they’ll be concerned about whether a candidate is still disciplined enough for work. Imperial College looked past that period of unemployment, and I’m grateful for it.
For our group, the Faraday Institution has allowed us to gain collaboration and expertise that was essential for creating PyBaMM. Our collaborators at the University of Birmingham have produced experimental data that was invaluable to our work. I also worked on a collaborative review paper led by colleagues from the universities of Oxford and Portsmouth.
What are your career aspirations?
Governments and private companies are investing heavily in battery research, so I have plenty of options that I’m still exploring. Even if I wanted to go into a different field, I have picked up many transferable skills in my work as a battery researcher. In the past, I have been rejected for software jobs due to a lack of experience. PyBaMM has allowed me to develop those skills to enter that sector if I want to.
What advice would you have liked to have given your younger self starting out on your career?
I would tell myself to think harder about my career earlier. I put it off for a long time because it’s so daunting. Sometimes I feel like I’m waiting for the perfect job or fellowship opportunity to drop into my lap, but that’s unrealistic. Do what makes you happy, and there are plenty of jobs where you feel supported and happy and like your work is having an impact. I would also tell myself that I chose the right field!
If people want to find out more about your research, where would you point them to?
I have a talk on YouTube about lithium plating in Li-ion batteries
They can also find out more about PyBaMM from the Faraday Institution Collaboration Award YouTube video.
Published October 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.