‘I chose to study my PhD with the AAPS CDT because I saw the opportunity to build something good together, learn from other people, and solve some of the world’s most pressing problems.’ — Mac Geoffrey Ajaereh, Integrated PhD in Advanced Automotive Propulsion Systems

In pursuing a PhD, I wanted to focus on addressing sustainability and environmental changes. My decision was influenced by my prior experience working on power systems and renewable energy during my MSc studies. Through this work, I recognised the pivotal role that batteries play in shaping the future of energy storage, transportation, and electronics. This realisation motivated me to seek a more profound understanding of batteries and their implications.

Further expanding my expertise while actively participating in cutting-edge research initiatives made undertaking a PhD an exhilarating prospect for me. What particularly drew me to the AAPS Centre for Doctoral Training (CDT) was its inclusive and diverse community of individuals from varied backgrounds. The CDT’s collaborative environment offers a plethora of intriguing and impactful projects, supported by a renowned academic team dedicated to addressing these challenges earnestly. Selecting AAPS CDT was a deliberate choice driven by the opportunity it presented to collectively create positive change, engage in knowledge exchange with peers, and tackle some of the most urgent global issues at hand.

Improving battery testing with ultrasound tech

My research uses ultrasound technology for testing lithium-ion batteries to estimate how much charge remains. This is known as the state of charge (SoC). My research aligns these SoC estimates with conventional electrical-based measurement methods. By leveraging high-frequency waves to evaluate the elastic changes during charging and discharging, this approach offers a non-invasive and cost-effective means to enhance the accuracy of SoC assessments.

Drawing on my MSc background in signal processing and power systems , coupled with a keen interest in battery research, I was drawn to this investigation spearheaded by Dr Christopher Vagg and Dr Charles Courtney, who now serve as my project mentors. The escalating use of lithium-ion batteries across various sectors underscores the necessity to comprehensively characterise their properties. My primary focus is on deciphering the state of charge measurements to address potential health issues that could compromise their efficacy across diverse applications.

Advancing battery tech for a safer future

One of the key challenges I address involves leveraging ultrasound technology for accurate battery health assessment, bypassing inaccuracies that can arise from voltage and current measurements. Ultrasound technology can identify changes in battery elasticity using specialised transducers, offering a non-destructive and cost-efficient solution. In my approach, I combine both ultrasound contact and non-contact testing methods. Contact tests entail positioning transducers between battery samples for internal evaluations. Non-contact tests require submerging batteries and transducers in water to perform spatial measurements across various points.

I expect my research to result in enhancing the dependability of battery management systems by utilising precise ultrasound data to determine the state of charge. This strategy should improve diagnostic capabilities and enable the early detection of potential battery issues, thereby reducing the chances of failures. Integrating ultrasound technology into battery management systems will not only support safety research but also contribute to industry initiatives. The use of compact and affordable ultrasound transducers in battery operations can enhance safety and reliability, thereby promoting the widespread adoption of electric vehicles. This effort emphasises collaborative endeavours to advance battery technologies for the betterment of society.

A memorable PhD experience

A highlight of my PhD was collaborating with experts from Bath and Penn State Universities on a work package. Working with skilled acousticians and material scientists, we innovated in ultrasonic testing, especially in battery analysis. This experience boosted my confidence and enhanced my project delivery at Bath.

One key skill I honed that’s crucial is effective communication. I now engage confidently with diverse audiences, radiating genuine enthusiasm for my research. AAPS CDT provided a platform for refining my communication style, enabling me to convey information clearly and concisely, sparking fresh dialogues and ideas.

Upon completing my PhD, I aspire to contribute my expertise to groundbreaking projects centred around physical acoustics, signal processing, and materials characterisation. Specifically, I want to target pivotal industries like energy storage, semiconductors, and technology. This endeavour could unfold within the dynamic realms of a research institution or a forward-thinking consulting firm.

‘The collaboration was the standout experience for me during my research journey. I have always valued teamwork, feedback, and learning from others. I was particularly surprised by the strength of these aspects when working with a team of individuals possessing diverse intellectual skills.’ — Mac Geoffrey Ajaereh, Integrated PhD in Advanced Automotive Propulsion Systems