Ultrasound Non-destructive Evaluation for Battery Management Systems.

Recent research has shown that ultrasound can detect the changes in material elasticity that occur as batteries undergo charging and discharging, enabling accurate measurement of the battery's state of charge. Our study aims to build on this approach by implementing it in automotive batteries, allowing for continuous monitoring of the battery's charge level and structural health during normal use.

Lithium-ion battery cells are widely recognized as a crucial component of sustainable transportation solutions. Incorporating ultrasound for charge monitoring can enhance the performance of these cells. Traditional methods for measuring the battery state of charge (SOC) rely on tracking voltage and current, but such methods suffer from limited efficiency and accuracy. In contrast, ultrasound enables direct SOC measurement at any time, independent of charge history, thus eliminating errors that may accumulate in successive measurements. This technology can provide highly accurate SOC readings, improve battery range estimation, and enhance the structural integrity of the battery.

Previously, successful demonstration of ultrasound charge monitoring on an individual battery cell was carried out in a laboratory environment. The changes in elastic properties and density of lithium-ion batteries affect the wave speed travelling through the test cell, and this wave speed is measured by determining the time taken by the longitudinal wave to traverse the cell. This information is then used to determine the battery SOC. However, automotive batteries consist of several cells stacked together, and hence, our research aims to investigate the application of various ultrasonic techniques to multiple cells within a battery module and its impact on module design.

To achieve this, we will incorporate a built-in test system in a laboratory environment to collect data that will subsequently be analysed using signal processing and numerical modelling techniques in predictive machine learning. Initially, the equipment will include an ultrasonic pulse-generator, ultrasonic probes, a custom test bed, and an individual lithium-ion cell before moving on to multiple cells stacked in series. Therefore, we aim to address the challenges posed by offline, single-cell, history-dependent, complex, and costly SOC prediction techniques. Additionally, we aim to embed an ultrasonic network configuration relevant to the automotive industry.

Our research aims to gain a comprehensive understanding of the physiochemical characteristics of lithium-ion batteries, with the goal of advancing the sustainable scalability of the automotive sector, particularly as electric vehicle deployment continues to increase. Specifically, we seek to provide new insights into the physiochemical changes of lithium-ion batteries, enabling more accurate determination of state of charge (SOC) and state of health (SOH) information. Our approach aims to extract this information in a cost-effective manner, without the need for expensive equipment, thus facilitating battery management systems that can provide accurate outputs under driving conditions. By offering a viable alternative to current SOC/SOH determination methods, our work can contribute to minimising manufacturing costs, reducing material requirements, and achieving a simple yet effective solution that moves the automotive industry towards sustainability.

Impact Summary

This proposal has been developed from the ground up to guarantee the highest level of impact. The two principal routes towards impact are via the graduates that we train and by the embedding of the research that is undertaken into commercial activity. The impact will have a significant commercial value through addressing skills requirements and providing technical solutions for the automotive industry - a key sector for the UK economy.

The graduates that emerge from our CDT (at least 84 people) will be transformative in two distinct ways. The first is a technical route and the second is cultural.

In a technical role, their deep subject matter expertise across all of the key topics needed as the industry transitions to a more sustainable future. This expertise is made much more accessible and applicable by their broad understanding of the engineering and commercial context in which they work. They will have all of the right competencies to ensure that they can achieve a very significant contribution to technologies and processes within the sector from the start of their careers, an impact that will grow over time. Importantly, this CDT is producing graduates in a highly skilled sector of the economy, leading to jobs that are £50,000 more productive per employee than average (i.e. more GVA). These graduates are in demand, as there are a lack of highly skilled engineers to undertake specialist automotive propulsion research and fill the estimated 5,000 job vacancies in the UK due to these skills shortages. Ultimately, the CDT will create a highly specialised and productive talent pipeline for the UK economy.

The route to impact through cultural change is perhaps of even more significance in the long term. Our cohort will be highly diverse, an outcome driven by our wide catchment in terms of academic background, giving them a 'diversity edge'. The cultural change that is enabled by this powerful cohort will have a profound impact, facilitating a move away from 'business as usual'.

The research outputs of the CDT will have impact in two important fields - the products produced and processes used within the indsutry. The academic team leading and operating this CDT have a long track record of generating impact through the application of their research outputs to industrially relevant problems. This understanding is embodied in the design of our CDT and has already begun in the definition of the training programmes and research themes that will meet the future needs of our industry and international partners. Exchange of people is the surest way to achieve lasting and deep exchange of expertise and ideas. The students will undertake placements at the collaborating companies and will lead to employment of the graduates in partner companies.

The CDT is an integral part of the IAAPS initiative. The IAAPS Business Case highlights the need to develop and train suitably skilled and qualified engineers in order to achieve, over the first five years of IAAPS' operations, an additional £70 million research and innovation expenditure, creating an additional turnover of £800 million for the automotive sector, £221 million in GVA and 1,900 new highly productive jobs.

The CDT is designed to deliver transformational impact for our industrial partners and the automotive sector in general. The impact is wider than this, since the products and services that our partners produce have a fundamental part to play in the way we organise our lives in a modern society. The impact on the developing world is even more profound. The rush to mobility across the developing world, the increasing spending power of a growing global middle class, the move to more urban living and the increasingly urgent threat of climate change combine to make the impact of the work we do directly relevant to more people than ever before. This CDT can help change the world by effecting the change that needs to happen in our industry.