Dr Juyeon Park, Principal Research Scientist and Technical Lead of Energy Storage Research at the National Physical Laboratory, spoke to The Innovation Platform about the development and commercialisation of high energy density batteries.
The National Physical Laboratory (NPL) works closely with the research community and industry to develop advanced measurement techniques, modelling tools, and standard test methods as part of government supported goals to maximise the performance, durability, and safety of the next generation of environmentally friendly energy storage devices.
Dr Juyeon Park’s research at NPL centres on energy storage devices, such as batteries and supercapacitors, but she is also a Fellow of the Institute of Materials, Minerals & Mining (FIMMM), a member of the Electrochemical Society (ECS), and a Certified Quality Engineer (CQE) of the American Society for Quality (ASQ).
Lisa Carnwell, Managing Editor at The Innovation Platform, spoke to Dr Park about the role that batteries play in the UK’s decarbonisation targets and how NPL can support the development and commercialisation of high energy density batteries.
Can you outline some of the energy storage research NPL is involved in?
I am currently working on a range of battery projects to create innovative standard test methods as diagnostic tools and to solve both scientific and engineering problems for battery performance and degradation.
Current energy storage research includes:
- The development of in situ/operando measurements for energy-related systems;
- The standardisation of reference cell design and improvements to electrochemical impedance spectroscopy analysis;
- The cost-effective performance assessment for battery second life;
- The identification and validation of key experimental parameters for electrochemical modelling to predict battery life and state of health (SoH);
- The correlation of electrochemical measurements with dimensional metrology and post-mortem analysis;
- Battery balancing and thermal management for battery longevity;
- A fault tree analysis of failure modes for safety issues;
- The next-generation energy storage systems (e.g. Na-ion batteries and solid-state electrolyte batteries) by developing measurement and modelling techniques to maximise the performance and durability of the next generation of environmentally-friendly energy devices; and
- Hybrid energy-related systems (photovoltaic cells, hydrogen technologies, supercapacitor to energy storage systems).
Wider energy storage (and conversion) research at NPL has led to the publication of energy transition reports that highlight current measurement challenges in the energy industry.
As part of the UK’s decarbonisation efforts, what role do batteries play, and what immediate challenges do we face?
NPL has carried out an extensive survey with battery experts from across the battery supply chain and industry to identify and prioritise measurement challenges that could create bottlenecks in the progress of widespread battery deployment.
The survey resulted in five challenge areas as high measurement priorities:
- Ensuring quality control throughout the manufacturing process by developing cost-effective screening tools;
- Developing diagnostic techniques to monitor the health state of batteries;
- Developing predictive models for battery performance and lifetime;
- Identifying end of life thresholds for second life and recycling; and
- Establishing standards for state estimation to generate more reliable and comparable data.
The electric vehicle era will be advanced by high energy density batteries with a low cost, as part of the UK’s decarbonisation efforts. By 2030, 60 GWh of gigafactory battery production capacity will be required to supply electricity to 1 million electric vehicles.
In order to move away from the internal combustion engine and to resolve charging inconvenience (which is the biggest disadvantage of electric vehicles), 2.3 million chargers need to be installed across the UK within the next 10 years for drivers to be able to easily charge electric vehicles anytime and anywhere.1
The 2021 report from SMMT: Delivering The Triple Bottom Line: A Blueprint For The Electric Vehicle Revolution also highlighted that in order for drivers to easily charge vehicles, many would want a charging point at their own home. Where this is not possible, ‘there must be a commitment to expand on-street public charging in residential areas.’ In order to meet the requirement for enough public charging points to deliver an electric car revolution, it is estimated that we need to create ‘at least 700 public charging points a day until 2030’.
Lithium-ion batteries have enabled the energy density of batteries to increase, but what new research and development is taking place to supersede and improve this further?
To overcome the current issues, which include the limited availability of lithium and cobalt raw materials, as well as safety concerns in Li-ion batteries, we must look at the benefits of using batteries for second use. Rechargeable batteries, analogous to Li-ion batteries but using naturally abundant elements such as sodium, and all solid-state and Li-ion batteries for second use, are being developed and improved, which is an important step.
In line with such demands, we have participated in government-funded battery research under The Faraday Battery Challenge, as well as European projects, combining expertise from multiple scientific disciplines to develop battery metrology to assess battery performance and to solve new industrial manufacturing problems. This work combines a variety of electrochemical and chemical characterisation techniques, as well as considering new theory development to underpin the best practice interpretation of measurements.
One such Faraday Challenge project concerned battery degradation. NPL, along with a cross-disciplinary consortium of researchers and industry partners, looked to develop a comprehensive mechanistic understanding of the relationship between external stimuli (such as temperature and cycling rate), and the physical and chemical processes occurring inside the battery that lead to degradation.
Phase 1 of the project (2018-2021) covered both chemical and material driven degradation, electrochemical signatures of degradation, and the synthesis of materials.
As part of NPL’s energy storage research activities, we are also active in a number of other research projects, including:
- The Faraday Battery Challenge project, Project VALUABLE – a UK consortium set up to develop testing and measurement techniques to enable recycling, reuse, and remanufacturing of automotive Li-ion batteries at their end-of-life;
- European Metrology Research Project LibForSecUse on the standardisation of impedance measurements on Li-ion batteries for second life applications, leading to a state of health model based on electrochemical impedance data;
- The Faraday Institution FutureCat project – NPL is providing support to develop and maintain a suite of standard protocols for fabrication, testing, and postmortem evaluation of Li-ion cells. Best practice in battery testing and postmortem analysis will be shared through round-robin test programmes and two-way secondments, which will upskill the project partners and increase the likelihood of significant breakthroughs;
- Support to post-COVID-19 industrial recovery via fully funded assistance to UK-based companies through the Measurement for Recovery (M4R) programme, under which NPL provided collated battery cycling data to Faraday Battery — a battery pack development start-up; and
- Measurement science research funded directly by the UK Department of Business, Energy & Industrial Strategy (BEIS).
One recent achievement of the funded research was the development of an optimised cell configuration for Raman spectroscopy measurement on energy storage materials, using simulation-led cell design followed by experimental implementation.
When successful, this methodology provides essential confidence that observations about electrode material chemistry and mechanisms inferred from operando Raman spectroscopy can be applied in the technological development of commercial electrochemical energy storage devices.
Translating battery research and development into a workable and efficient manufacturing process is key if we are to deliver a decarbonised transport sector, but what are the challenges, and how do we overcome them?
Quality control and Bill of Material (BoM) costs are the key items for mass production that are rarely considered in R&D. To close the gap between R&D and industrial requirements, cultivating skilled personnel via practical training programmes is essential. Nurturing strong partnerships to share and utilise industrial data at the R&D stage (which is often blocked due to confidentiality) is also crucial for the rapid development of industrial goals.
Your research at NPL also includes creating innovative standard test methods. What does this involve, and do you believe that any standardisation could, or should, be implemented globally?
Creating innovative standard test methods requires new ideas, collaboration, consensus, and rigorous analysis. It involves test method development and validation, interlaboratory comparison, and progressive refinement. However, it is also vital to understand industry needs through regular consultation and engagement.
The battery market is truly global, and selected test methods need to be taken forward for international standardisation, particularly where they protect the interests of UK companies.
Finally, how do you see battery research developing over the next five years, and how can we address battery production sustainably?
The current battery research goals include, safer, longer lasting and cheaper batteries that have more power and greater energy density. Li-ion batteries will be a mainstream technology in the energy storage market over the next five years; however, research will also focus on the development of complementary areas, including hydrogen fuel cells for an eco-friendly approach.
I must also highlight that for battery production to be sustainable, battery materials should be extracted and recycled as much as possible, and a robust circular battery economy must be developed to reuse and recycle batteries. NPL is working as part of a UK consortium to develop testing and measurement towards recycling, reuse and remanufacturing of automotive Li-ion batteries at the end of their life.
Please note, this article will also appear in the seventh edition of our quarterly publication.