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Large lithium-ion batteries (LIBs) demonstrate different performance and lifetime compared to small LIB cells, owing to the size effects generated by the electrical configuration and property imbalance. However, the calculation time for performing life predictions with three-dimensional (3D) cell models is undesirably long. In this paper, a lumped cell model with equivalent resistances (LER cell model) is proposed as a reduced order model of the 3D cell model, which enables accurate and fast life predictions of large LIBs. The developed LER cell model is validated via the comparisons with results of the 3D cell models by simulating a 20-Ah commercial pouch cell (NCM/graphite) and the experimental values. In addition, the LER cell models are applied to different cell types and sizes, such as a 20-Ah cylindrical cell and a 60-Ah pouch cell.
Hong-Keun Kim; Kyu-Jin Lee. Scale-Up of Physics-Based Models for Predicting Degradation of Large Lithium Ion Batteries. Sustainability 2020, 12, 8544 .
AMA StyleHong-Keun Kim, Kyu-Jin Lee. Scale-Up of Physics-Based Models for Predicting Degradation of Large Lithium Ion Batteries. Sustainability. 2020; 12 (20):8544.
Chicago/Turabian StyleHong-Keun Kim; Kyu-Jin Lee. 2020. "Scale-Up of Physics-Based Models for Predicting Degradation of Large Lithium Ion Batteries." Sustainability 12, no. 20: 8544.
Large lithium-ion batteries (LIBs) in electric vehicles and energy storage systems demonstrate different performance and lifetime compared to small LIB cells, owing to the size effects generated by the electrical configuration and property imbalance. However, the calculation time for performing life predictions with three-dimensional (3D) cell models is undesirably long. In this paper, a lumped cell model with equivalent resistances (LER cell model) is proposed as a reduced order model of the 3D cell model, which enables accurate and fast life predictions of large LIBs. The developed LER cell model is validated via the comparisons with results of the 3D cell models by simulating a 20-Ah commercial pouch cell (NCM/graphite) and the experimental values. In addition, the LER cell models are applied to different cell types and sizes, such as a 20-Ah cylindrical cell and a 60-Ah pouch cell.
Hong-Keun Kim; Kyu-Jin Lee. Scale-up of Physics-based Models for Predicting Degradation of Large Lithium Ion Batteries. 2020, 1 .
AMA StyleHong-Keun Kim, Kyu-Jin Lee. Scale-up of Physics-based Models for Predicting Degradation of Large Lithium Ion Batteries. . 2020; ():1.
Chicago/Turabian StyleHong-Keun Kim; Kyu-Jin Lee. 2020. "Scale-up of Physics-based Models for Predicting Degradation of Large Lithium Ion Batteries." , no. : 1.
The existing series hybrid electric bus (SHEB) uses an ultra-capacitor (UC) to extend battery life, mitigate vehicle weight, and reduce cost. However, previous studies did not clearly identify the operation timing and load of the UC for efficiency improvement in an SHEB. This paper proposes novel efficiency improvement factors, with their application criteria for the ideal operation timing and load of the UC in an SHEB. The factors are the threshold of the required power of the motor (TRPM), slope of the power split ratio (SPSR), and y-axis intercept of the power split ratio (YPSR). The TRPM determines the duration of using just the battery. The SPSR or YPSR determine the most efficient load ratio between the battery and UC. The criteria for using them are set using particle swarm optimization. Manhattan, Braunschweig, and Orange County driving cycles were used to reflect various road load conditions. The results showed that the proposed factors and their setting criteria guarantee a significant reduction in the fuel consumption and more energy-efficient SHEBs.
Giyeon Hwang; Kyungmin Lee; Jongmyung Kim; Kyu-Jin Lee; Sangyul Lee; Minjae Kim. Energy Management Optimization of Series Hybrid Electric Bus Using an Ultra-Capacitor and Novel Efficiency Improvement Factors. Sustainability 2020, 12, 7354 .
AMA StyleGiyeon Hwang, Kyungmin Lee, Jongmyung Kim, Kyu-Jin Lee, Sangyul Lee, Minjae Kim. Energy Management Optimization of Series Hybrid Electric Bus Using an Ultra-Capacitor and Novel Efficiency Improvement Factors. Sustainability. 2020; 12 (18):7354.
Chicago/Turabian StyleGiyeon Hwang; Kyungmin Lee; Jongmyung Kim; Kyu-Jin Lee; Sangyul Lee; Minjae Kim. 2020. "Energy Management Optimization of Series Hybrid Electric Bus Using an Ultra-Capacitor and Novel Efficiency Improvement Factors." Sustainability 12, no. 18: 7354.
A spatially-resolved isothermal calorimeter has been developed to measure distributions of heat generation rates in a pouch-type lithium-ion battery. When a 20 Ah LiFePO4 battery discharges currents at constant rates, the total heat generation rates measured by the calorimeter change according to the states-of-charge (SOC). However, the spatial deviations of heat generation rates remain relatively steady. The maximum heat generation rate is detected in the vicinity of the positive tab. From the measurements, localized Joule heat generation in metal current collectors is noted as a predominant cause of the thermal non-uniformity in pouch-type batteries.
Wanseob Jung; Hong Keun Kim; Minjae Kim; Kyu-Jin Lee. Spatial measurement of heat generation in a pouch-type lithium-ion battery. International Journal of Precision Engineering and Manufacturing 2016, 17, 1085 -1089.
AMA StyleWanseob Jung, Hong Keun Kim, Minjae Kim, Kyu-Jin Lee. Spatial measurement of heat generation in a pouch-type lithium-ion battery. International Journal of Precision Engineering and Manufacturing. 2016; 17 (8):1085-1089.
Chicago/Turabian StyleWanseob Jung; Hong Keun Kim; Minjae Kim; Kyu-Jin Lee. 2016. "Spatial measurement of heat generation in a pouch-type lithium-ion battery." International Journal of Precision Engineering and Manufacturing 17, no. 8: 1085-1089.
The Discrete element method (DEM) is used for solving microscopic mechanical behaviors of granular materials and has the advantage of being able to analyze the wheel-soil interactions on the off-road ground because soil deformation under a moving wheel is a discontinuous, non-uniform and nonlinear phenomenon. However, a challenge for applying DEM to the soil analysis is that determination of DEM parameters is not rooted in a clear understanding of relationships between the DEM parameters and soil conditions. This study modeled the plate-sinkage test based on DEM and produced the soil characteristic properties of the virtual soils to reveal effects of the DEM parameters on the vertical bearing capacity of the soil. A nominal model of the plate-sinkage test was developed with a chosen set of the DEM parameters, and its model results were compared with experimental data of actual Jumunjin sand. Also, parametric studies were conducted on particle density, Young’s modulus, friction coefficient and rolling friction coefficient.
Gichan Jang; Soojin Lee; Kyu-Jin Lee. Discrete element method for the characterization of soil properties in Plate-Sinkage tests. Journal of Mechanical Science and Technology 2016, 30, 2743 -2751.
AMA StyleGichan Jang, Soojin Lee, Kyu-Jin Lee. Discrete element method for the characterization of soil properties in Plate-Sinkage tests. Journal of Mechanical Science and Technology. 2016; 30 (6):2743-2751.
Chicago/Turabian StyleGichan Jang; Soojin Lee; Kyu-Jin Lee. 2016. "Discrete element method for the characterization of soil properties in Plate-Sinkage tests." Journal of Mechanical Science and Technology 30, no. 6: 2743-2751.