Developing parametrisation methods for physics-based models of lithium and sodium-ion batteries

O'Regan, Kieran Brendan ORCID: 0000-0002-5266-594X (2024). Developing parametrisation methods for physics-based models of lithium and sodium-ion batteries. University of Birmingham. Ph.D.

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Abstract

Lithium-ion batteries have become an important technology in the transition to renewable energy. Improvements in battery performance and cost reductions have led to their adoption in transport and grid storage applications to reduce carbon emissions. Battery models have been an important tool to achieve these improvements. Physics-based models, including the Doyle-Fuller-Newman model provide insight into the mass and charge transport processes within the individual battery components. The application of these battery models in industry and research has been limited by the availability of input parameters and the lack of published methodologies for parameterizing different cell formats and chemistries. Physics-based models have significant potential within industry, from optimising fast charging and battery manufacturing, but the main obstacle for widespread adoption is obtaining the parameters. Numerous parameters relating to the physical, electrochemical, and thermal properties of a battery. This research's experimental approach identifies key battery model parameters, improves methods, and creates accurate models for specific cells, offering insights for industry application and model development. This thesis develops parameterisation methodologies using physical, electrochemical, and thermal characterisation techniques to construct battery models that improve the understanding of battery kinetics/thermodynamics. Techniques including electrochemical impedance spectroscopy, galvanostatic intermittent titration technique, thermal measurement methods, and more are adapted to extract model inputs. This allows battery models that demonstrate high accuracy between simulated and experimental data to be developed. For lithium-ion batteries, a complete parameterisation workflow is developed to capture the thermal-electrochemical behaviour of a high energy commercial cylindrical cell and the property changes that occur during battery operation. This is accomplished by evaluating the dependency of parameters on temperature and state-of-charge. Furthermore, we found that traditional methods can be modified to better parameterise silicon additives, or new chemistries including sodium Our results demonstrate the importance and complementarity practical methods have in aiding model development and understanding. The novelty of this work lies in its approach to model development, utilizing experiments to identify the limitations of existing battery models and areas where simplifications can enhance utility without compromising the understanding of battery physics. This approach equips theorists with practical tools and insights, enabling significant advancements in the field of battery modelling. These methods have been commercialised and will be developed further to provide the several industries expertise into parameterisation and model development.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):