Publications
12 results found
Li R, O'Kane S, Huang J, et al., 2024, A million cycles in a day: Enabling high-throughput computing of lithium-ion battery degradation with physics-based models, Journal of Power Sources, Vol: 598, ISSN: 0378-7753
High-throughput computing (HTC) is a pivotal asset in many scientific fields, such as biology, material science and machine learning. Applying HTC to the complex physics-based degradation models of lithium-ion batteries enables efficient parameter identification and sensitivity analysis, which further leads to optimal battery designs and operating conditions. However, running physics-based degradation models comes with pitfalls, as solvers can crash or get stuck in infinite loops due to numerical errors. Also, how to pipeline HTC for degradation models has seldom been discussed. To fill these gaps, we have created ParaSweeper, a Python script tailored for HTC, designed to streamline parameter sweeping by running as many ageing simulations as computational resources allow, each with different parameters. We have demonstrated the capability of ParaSweeper based on the open-source platform PyBaMM, and the approach can also apply to other numerical models which solve partial differential equations. ParaSweeper not only manages common solver errors, but also integrates various methods to accelerate the simulation. Using a high-performance computing platform, ParaSweeper can run millions of charge/discharge cycles within one day. ParaSweeper stands to benefit both academic researchers, through expedited model exploration, and industry professionals, by enabling rapid lifetime design, ultimately contributing to the prolonged lifetime of batteries.
Xie Y, Hales A, Li R, et al., 2022, Thermal management optimization for large-format lithium-ion battery using cell cooling coefficient, Journal of The Electrochemical Society, Vol: 169, Pages: 1-10, ISSN: 0013-4651
The surface cooling technology of power battery pack has led to undesired temperature gradient across the cell during thermal management and the tab cooling has been proposed as a promising solution. This paper investigates the feasibility of applying tab cooling in large-format lithium-ion pouch cells using the Cell Cooling Coefficient (CCC). A fundamental problem with tab cooling is highlighted, the CCC for tab cooling decreases as capacity increases. Coupling low CCCs with greater heat generation leads to significant temperature gradients across the cell. Here, the "bottleneck" that limits heat rejection through the tabs is evaluated. The thermal resistance of the physical tabs is identified to be the main contributor towards the poor heat rejection pathway. A numerical thermal model is used to explore the effect of increased tab thickness and results showed that the cell-wide temperature gradients could be significantly reduced. At the negative tab, increasing from 0.2 mm to 2 mm led to a 100% increase in CCCneg whilst increasing the positive tab from 0.45 mm to 2 mm led to an 82% increasing in CCCpos. Together, this is shown to contribute to a 51% reduction in temperature gradient across the cell in any instance of operation.
Xie Y, Wang S, Li R, et al., 2022, Inhomogeneous degradation induced by lithium plating in a large-format lithium-ion battery, JOURNAL OF POWER SOURCES, Vol: 542, ISSN: 0378-7753
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- Citations: 10
Li R, O'Kane S, Marinescu M, et al., 2022, Modelling solvent consumption from SEI layer growth in lithium-ion batteries, Journal of The Electrochemical Society, Vol: 169, Pages: 1-14, ISSN: 0013-4651
Predicting lithium-ion battery (LIB) lifetime is one of the most important challenges holding back the electrification of vehicles,aviation, and the grid. The continuous growth of the solid-electrolyte interface (SEI) is widely accepted as the dominantdegradation mechanism for LIBs. SEI growth consumes cyclable lithium and leads to capacity fade and power fade via severalpathways. However, SEI growth also consumes electrolyte solvent and may lead to electrolyte dry-out, which has only beenmodelled in a few papers. These papers showed that the electrolyte dry-out induced a positive feedback loop between loss of activematerial (LAM) and SEI growth due to the increased interfacial current density, which resulted in capacity drop. This work,however, shows a negative feedback loop between LAM and SEI growth due to the reduced solvent concentration (in our case,EC), which slows down SEI growth. We also show that adding extra electrolyte into LIBs at the beginning of life can greatlyimprove their service life. This study provides new insights into the degradation of LIBs and a tool for cell developers to designlonger lasting batteries.
Roe C, Feng X, White G, et al., 2022, Immersion cooling for lithium-ion batteries – a review, Journal of Power Sources, Vol: 525, Pages: 231094-231094, ISSN: 0378-7753
Battery thermal management systems are critical for high performance electric vehicles, where the ability to remove heat and homogenise temperature distributions in single cells and packs are key considerations. Immersion cooling, which submerges the battery in a dielectric fluid, has the potential of increasing the rate of heat transfer by 10,000 times relative to passive air cooling. In 2-phase systems, this performance increase is achieved through the latent heat of evaporation of the liquid-to-gas phase transition and the resulting turbulent 2-phase fluid flow. However, 2-phase systems require additional system complexity, and single-phase direct contact immersion cooling can still offer up to 1,000 times improvements in heat transfer over air cooled systems. Fluids which have been considered include: hydrofluoroethers, mineral oils, esters and water-glycol mixtures. This review therefore presents the current state-of-the-art in immersion cooling of lithium-ion batteries, discussing the performance implications of immersion cooling but also identifying gaps in the literature which include a lack of studies considering the lifetime, fluid stability, material compatibility, understanding around sustainability and use of immersion for battery safety. Insights from this review will therefore help researchers and developers, from academia and industry, towards creating higher power, safer and more durable electric vehicles.
LI R, REN D, WANG S, et al., 2021, Non-destructive local degradation detection in large format lithium-ion battery cells using reversible strain heterogeneity, Journal of Energy Storage, Vol: 40, Pages: 102788-102788, ISSN: 2352-152X
Li Y, Han X, Feng X, et al., 2021, Errors in the reference electrode measurements in real lithium-ion batteries, Journal of Power Sources, Vol: 481, Pages: 228933-228933, ISSN: 0378-7753
Li Y, Liu X, Ren D, et al., 2020, Toward a high-voltage fast-charging pouch cell with TiO2 cathode coating and enhanced battery safety, Nano Energy, Vol: 71, Pages: 104643-104643, ISSN: 2211-2855
Feng X, Merla Y, Weng C, et al., 2020, A reliable approach of differentiating discrete sampled-data for battery diagnosis, ETRANSPORTATION, Vol: 3, ISSN: 2590-1168
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- Citations: 61
Ren D, Hsu H, Li R, et al., 2019, A comparative investigation of aging effects on thermal runaway behavior of lithium-ion batteries, eTransportation, Vol: 2, Pages: 100034-100034, ISSN: 2590-1168
Tomaszewska A, Chu Z, Feng X, et al., 2019, Lithium-ion battery fast charging: A review, eTransportation, Vol: 1, Pages: 1-28, ISSN: 2590-1168
In the recent years, lithium-ion batteries have become the battery technology of choice for portable devices, electric vehicles and grid storage. While increasing numbers of car manufacturers are introducing electrified models into their offering, range anxiety and the length of time required to recharge the batteries are still a common concern. The high currents needed to accelerate the charging process have been known to reduce energy efficiency and cause accelerated capacity and power fade. Fast charging is a multiscale problem, therefore insights from atomic to system level are required to understand and improve fast charging performance. The present paper reviews the literature on the physical phenomena that limit battery charging speeds, the degradation mechanisms that commonly result from charging at high currents, and the approaches that have been proposed to address these issues. Special attention is paid to low temperature charging. Alternative fast charging protocols are presented and critically assessed. Safety implications are explored, including the potential influence of fast charging on thermal runaway characteristics. Finally, knowledge gaps are identified and recommendations are made for the direction of future research. The need to develop reliable in operando methods to detect lithium plating and mechanical degradation is highlighted. Robust model-based charging optimisation strategies are identified as key to enabling fast charging in all conditions. Thermal management strategies to both cool batteries during charging and preheat them in cold weather are acknowledged as critical, with a particular focus on techniques capable of achieving high speeds and good temperature homogeneities.
Li R, Ren D, Guo D, et al., 2019, Volume Deformation of Large-Format Lithium Ion Batteries under Different Degradation Paths, Journal of The Electrochemical Society, Vol: 166, Pages: A4106-A4114, ISSN: 0013-4651
<jats:p>Lithium ion batteries experience volume deformation in service, leading to a large internal stress in modules and potential safety issues. Therefore, understanding the mechanism of volume deformation of a lithium ion battery is critical to ensuring the long-term safety of electric vehicles. In this work, the irreversible and reversible deformation of a large-format lithium ion battery under four degradation paths, including cycling at −5°C/1 C, 55°C/1 C and 25°C/4 C, and storage at 55°C/100% state of charge, are investigated using laser scanning. The reversible deformation decreases while the irreversible deformation increases as batteries age, following a linear trend with the state of health. The mechanism behind irreversible deformation is investigated using incremental capacity analysis and scanning electron microscopy. The irreversible deformation of the battery cycled at 25°C/4 C and stored at 55°C becomes extremely large below 80% state of health, mainly because of the additional deposit layers on the anode and increased gas production, respectively. Mechanical calculations show the huge stress in the aged modules. Proper spacers between batteries are suggested to reduce such damage. This study is valuable for understanding the mechanical safety of battery modules.</jats:p>
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