Design and multi-objective optimization of single-phase natural-convection immersion cooling for cylindrical Lithium-ion battery packs in subaquatic energy storage systems

The low cost, simplicity, and easy use of battery-powered multirotor aircraft has led to their adoption in commercial, industrial, agricultural, and military applications. These aircraft, however, have limited payloads and shorter endurance and range than fuel-powered conventional aircraft. While individual use cases of multirotor craft vary drastically, one of the most important variables in performance is aircraft mass. Lithium batteries offer an energy density high enough for most small multirotor flight applications, however these batteries often constitute a significant portion of the aircraft’s mass. The mass fraction of the multirotor that consists of batteries often inhibits flight characteristics similarly to an increased payload. This research proposes the use of lithium-ion batteries in a multifunctional configuration, providing both energy for flight operations and structural load-bearing capability. This implementation is proposed to decrease the structural frame mass and thus increase multirotor performance characteristics such as payload capacity and flight time. Multifunctional lithium-based batteries have been previously proposed for the efficient use of space and mass in electric vehicles [1]. Standard 18650 cylindrical battery cells (Panasonic NCR18650B) were used in this research as they are commercially available, have a circular cross-section, and have high energy density relative to prismatic or pouch lithium polymer cells often used in this application. The proposed configuration consists of a thin tube filled with 18650 cells to provide a multifunctional member with a high bending stiffness. The method of reinforcement is similar to that of the jellyroll electrodes placed within a thin cylindrical battery shell being substantially stronger than either alone [2]. The proposed configuration is compared with the non-reinforced tubing in three-point bending and shown to increase stiffness due to the load-bearing capabilities of the battery cells. The mechanical abuse tolerance of bare battery cells has been extensively tested, however, little data is available for reinforced cells or multifunctional cell configurations [3]. It has been noted that high strain rate and reduced state of charge negatively affect the integrity of Li-ion batteries [4]. Additionally, the mechanical properties of the jellyroll electrodes have been found to be anisotropic, contributing to non-uniform mechanical response of the cell as a whole [5]. In this study, testing was performed at a zero state of charge and a high strain rate to simulate the worst-case relative performance of the multifunctional members. In addition, multiple sizes of reinforced members were tested to investigate the scalability of the multifunctional configuration. The cylindrical lithium-ion structural battery presented here can provide both a power source and a load-bearing member for multirotor aircraft. Battery reinforcement is shown to provide up to 1100% stiffness and 750% yield strength improvements. Substitution of the proposed structural battery for aluminum tubes in a notional quadcopter design showed a 41% improvement in theoretical maximum hover time. This research motivates future multifunctional battery configurations with topologically optimized designs for various loading scenarios. [1] Zhang YC, Ma J, Singh AK, et al. (2017) Multifunctional structural lithium-ion battery for electric vehicles. Journal of Intelligent Material Systems and Structures 28: 1603-1613.[2] Zhang XW and Wierzbicki T. (2015) Characterization of plasticity and fracture of shell casing of lithium-ion cylindrical battery. Journal of Power Sources 280: 47-56.[3] Zhu J, Zhang XW, Sahraei E, et al. (2016) Deformation and failure mechanisms of 18650 battery cells under axial compression. Journal of Power Sources 336: 332-340.[4] Xu J, Liu BH, Wang XY, et al. (2016) Computational model of 18650 lithium-ion battery with coupled strain rate and SOC dependencies. Applied Energy 172: 180-189.[5] Sahraei E, Campbell J and Wierzbicki T. (2012a) Modeling and short circuit detection of 18650 Li-ion cells under mechanical abuse conditions. Journal of Power Sources 220: 360-372. Figure 1

Effect of mechanical vibration on phase change material based thermal management system for a cylindrical lithium-ion battery at high ambient temperature and high discharge rate

Cylindrical lithium-ion batteries are widely used in consumer electronics, electric vehicles, and energy storage applications. However, safety risks due to thermal runaway-induced fire and explosions have prompted the need for safety analysis methodologies. Though cylindrical batteries often incorporate safety devices, the safety of the battery also depends on its design and manufacturing processes. This study conducts a design and process failure mode and effect analysis (DFMEA and PFMEA) for the design and manufacturing of cylindrical lithium-ion batteries, with a focus on battery safety.

RETRACTED: The influence of battery distance on a hybrid air-cooled cylindrical lithium-ion battery phase change material thermal management system for storing solar energy

Lithium-ion batteries come in various form factors, with cylindrical lithium-ion batteries featuring electrodes wound in a jellyroll shape. This winding process introduces curvature to the electrodes, resulting in varying curvatures depending on the radius of the jellyroll.In this study, we investigated the influence of electrode curvature within cylindrical lithium-ion batteries on battery performance. We fabricated single-coated electrode pouch cells using an NCM622 cathode and graphite-silicon composite anode. We developed devices to simulate various curvatures based on the radius of the jellyroll and applied these devices to the pouch cells to analyze the effect of curvature on the cell’s charging and discharging behavior.The results revealed that changes in electrode curvature, depending on the radius of the jellyroll, alter the area available for reaction at the anode. As a result, the potential of the anode changed, leading to a corresponding change in the potential of the cathode at the same full cell's cut-off charging voltage. Additionally, we observed differences in cathode/anode utilization depending on whether they were on the inner or outer coated surface, even with the same curvature. Particularly, we found an increased risk of lithium deposition when the curvature is large with the anode on the outer coated surface. Furthermore, these effects influence changes in silicon utilization in the anode, affecting the thickness expansion and degradation differences in the anode. Consequently, the non-uniformity of cell reactions due to electrode curvature increases. Therefore, we propose methods for designing cylindrical lithium-ion batteries to minimize such non-uniformity in reactions.Our research emphasizes the importance of curvature within cylindrical lithium-ion batteries and its impact on battery performance by elucidating the mechanism of battery performance changes due to electrode curvature. These findings are expected to contribute to the design and development of cylindrical lithium-ion batteries. Figure 1

Homogenization and finding the constitutive model of jellyroll in cylindrical lithium-ion batteries can be challenging because of their form factor. Taking samples out of the original jellyroll wounding or compressing cell assembly in its cylindrical coordinates are two possibilities for measuring the homogenized lateral strength of the cell. However, the former causes loss of accuracy due to changing constraints and electrolyte environment, and the latter requires complex fixtures that are not readily available or even practical to manufacture. Various approaches have been suggested by researchers to circumvent the above difficulties and allow the extraction of hardening curves. However, the precision of those approaches diminishes when the cells are under global compression vs local punch deformations. In this study, an updated homogenization method is established, using a lateral compression test on the jellyroll. The homogenization method is based on the assumption that the circular cross-section of the jellyroll under compression is deformed in an elliptical shape. Then the principle of virtual work is used to extract the hardening curve. To validate the above characterization model, isotropic and anisotropic finite element models were developed using crushable foam and modified honeycomb material models from the LS-DYNA library. Four sets of cell-level experiments were performed on cylindrical batteries using custom-designed fixtures, including flat lateral compression, rod indentation, hemispherical punch, and three-point bending. The voltage and surface temperature of the batteries were measured to capture the onset of short circuit during the tests. Comparison of the simulation results confirmed that the proposed homogenization method and the FE models can predict the behavior of cylindrical lithium-ion batteries with much higher accuracy compared to the currently available methods presented in the literature.

Analytical solution, optimization and design of a phase change cooling pack for cylindrical lithium-ion batteries

Simultaneous cooling of plate and cylindrical batteries in an air-cooled lithium battery thermal management system, by changing the distances of the batteries from each other and the pack wall

Effect of splitter damper on airflow conduction for thermal management of a lithium-ion battery cooling system with plate and cylindrical batteries

A compact and lightweight liquid-cooled thermal management solution for cylindrical lithium-ion power battery pack

An online temperature estimation for cylindrical lithium-ion batteries based on simplified distribution electrical-thermal model

RETRACTED:Economic cost and numerical evaluation of cooling of a cylindrical lithium-ion battery pack using air and phase change materials

Study on the thermal interaction and heat dissipation of cylindrical Lithium-Ion Battery cells

An exact prediction of temperature inside cylindrical lithium ion (Li-ion) batteries is important for their safe operation, extended life expectancy and development of next generation battery management systems. Research attempts have been made to place temperature sensors inside cylindrical Li-ion batteries [1, 2], but such arrangements are not yet commercially available. Alternatively, a computational fluid dynamics (CFD) approach can be used to accurately predict internal temperature profiles. This computational technique couples the multiphysics phenomena occurring inside cylindrical Li-ion batteries [3, 4]. In this work we present a coupled one dimensional electrochemical and three dimensional thermal CFD model, to predict internal and surface temperature profiles of a commercially available 21700 cylindrical Li-ion battery. Since the operating temperature has an important effect on Li-ion battery ageing, the CFD model is coupled with the solid electrolyte interphase (SEI) formation on the negative electrode. The SEI formation and growth is one of the main reasons that shortens the life expectancy of Li-ion batteries with liquid electrolytes and needs to be addressed in computational models [5]. The developed CFD model will be used to predict temperature profiles and SEI growth response to charge, discharge and rest duty-cycle periods of the 21700 cylindrical Li-ion battery. Surface temperature and voltage profiles acquired from the CFD model will be compared against experimental results to confirm the validity of the computational model. Such an extended model will represent a computational framework to potentially decrease the cost and number of 21700 cylindrical Li-ion battery experiments with different duty-cycle scenarios. It will also support the design of more advanced battery management systems and optimise the cooling and heating system of battery modules and packs.

Experimental study on a novel compact cooling system for cylindrical lithium-ion battery module