scholarly journals The Influence of Structure on the Electrochemical and Thermal Response of Li-Ion Battery Electrodes

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Prehit Patel ◽  
George J. Nelson
Keyword(s):  
Particle Size ◽  
Heat Generation ◽  
Active Material ◽  
Thermal Response ◽  
Lithium Ion ◽  
Local Heat ◽  
Spherical Particles ◽  
Electrode Thickness ◽  
Material Particle ◽  
Fast Charging

Abstract Advancement of lithium-ion batteries for transportation applications requires addressing two key challenges: increasing energy density and providing fast charging capabilities. The first of these challenges can be met using thicker electrodes. However, the implementation of thick electrodes inherently presents a trade-off with respect to fast charging. As the thickness is increased, transport limitations reduce the ability of the battery to meet aggressive charge conditions. At the particle scale, interactions between solid diffusion and reaction kinetics influence the effective storage of lithium. At the electrode scale, diffusion limitations can lead to local variations in salt concentrations and electric potential. These short-range and long-range effects can combine to influence local current and heat generation. In the present work, a pseudo-2D lithium-ion battery model is applied to understand how active material particle size, porosity, and electrode thickness impact local field variables, current, heat generation, and cell capacity within a single-cell stack. The model was built assuming that the active particles are representative spherical particles. The governing equations and boundary conditions were set following the common Newman model. Cell response under varied combinations of charge and discharge cycling is assessed for rates of 1 C and 5 C. Aggressive charge and discharge conditions lead to locally elevated C-rates and attendant increases in local heat generation. These variations can be impacted in part by tailoring electrode structures. To this end, results for parametric studies of active material particle size, porosity, and electrode thickness are presented and discussed.

The Influence of Structure on the Electrochemical and Thermal Response of Li-Ion Battery Electrodes

2019 ◽  
Author(s):  
Prehit Patel ◽  
George J. Nelson
Keyword(s):  
Particle Size ◽  
Lithium Ion Battery ◽  
Heat Generation ◽  
Active Material ◽  
Lithium Ion ◽  
Spherical Particles ◽  
Electrode Thickness ◽  
Material Particle ◽  
Trade Off ◽  
Fast Charging

Abstract The continued advancement of lithium ion batteries for transportation applications requires addressing two key challenges: increasing energy density and providing fast charging capabilities. The first of these challenges can be met in part through the use of thicker electrodes, which reduce the electrochemically inactive mass of the cell. However, implementation of thick electrodes inherently presents a trade-off with respect to fast charging capabilities. As thickness is increased, transport limitations exert greater influence on battery performance and reduce the ability of the battery to meet aggressive charge conditions. This trade-off can manifest over multiple length scales. At the particle-scale, interactions between solid diffusion and reaction kinetics influence the effective storage of lithium within the active material. At the electrode scale, diffusion limitations can lead to local variations in salt concentrations and electric potential. These short-range and long-range effects can combine to influence local current and heat generation. In the present work, a pseudo-2D lithium ion battery model is applied to understand how active material particle size, porosity, and electrode thickness impact local field variables, current, heat generation, and cell capacity within a single cell stack. COMSOL Multiphysics 5.2 is used to implement the pseudo-2D model of a lithium ion battery consisting of a graphite negative electrode, polymer separator, and lithium transition metal oxide positive electrode. Lithium hexafluorophosphate (LiPF6) in 1:1 ethylene carbonate (EC) and diethylene carbonate (DEC) was used as the electrolyte. The model was built assuming that the active particles are representative spherical particles. The governing equations and boundary conditions were set following the common Newman model. Cell response under varied combinations of charge and discharge cycling is assessed for rates of 1C and 5C. Aggressive charge and discharge conditions lead to locally elevated C-rates and attendant increases in local heat generation. These variations can be impacted in part by tailoring electrode structures. To this end, results for parametric studies of active material particle size, porosity, and electrode thickness are presented and discussed.

scholarly journals Mechanical Integrity of Conductive Carbon-Black-Filled Aqueous Polymer Binder in Composite Electrode for Lithium-Ion Battery

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1460
Author(s):  
Kehua Peng ◽  
Yaolong He ◽  
Hongjiu Hu ◽  
Shufeng Li ◽  
Bao Tao
Keyword(s):  
Carbon Black ◽  
Composite Electrode ◽  
Mechanical Stability ◽  
Critical Role ◽  
Active Material ◽  
Mechanical Damage ◽  
Lithium Ion ◽  
Spherical Particles ◽  
Inorganic Filler ◽  
Composite Electrodes

The mechanical stability of aqueous binder and conductive composites (BCC) is the basis of the long-term service of composite electrodes in advanced secondary batteries. To evaluate the stress evolution of BCC in composite electrodes during electrochemical operation, we established an electrochemical–mechanical model for multilayer spherical particles that consists of an active material and a solid-electrolyte-interface (SEI)-enclosed BCC. The lithium-diffusion-induced stress distribution was studied in detail by coupling the influence of SEI and the viscoelasticity of inorganic-filler-doped polymeric bonding material. It was found that tensile hoop stress plays a critical role in determining whether a composite electrode is damaged or not—and circumferential cracks may primarily initiate in BCC, rather than in other electrode components. Further, the peak tensile stress of BCC is at the interface with SEI and does not occur at full lithiation due to the relaxation nature of polymer composite. Moreover, mechanical damage would be greatly misled if neglecting the existence of SEI. Finally, the structure integrity of the binder and conductive system can be effectively improved by (1) increasing the carbon black content as much as possible in the context of meeting cell capacity requirements—it is greater than 27% and 50% for sodium alginate and the mixtures of carboxy styrene butadiene latex and sodium carboxymethyl cellulose, respectively, for composite graphite anode; (2) reducing the elastic modulus of SEI to less than that of BCC; (3) decreasing the lithiation rate.

Local Heat Generation in a Single Stack Lithium Ion Battery Cell

2015 ◽  
Vol 186 ◽  
pp. 404-412 ◽  
Author(s):  
C. Heubner ◽  
M. Schneider ◽  
C. Lämmel ◽  
A. Michaelis
Keyword(s):  
Lithium Ion Battery ◽  
Heat Generation ◽  
Lithium Ion ◽  
Local Heat ◽  
Battery Cell ◽  
Local Heat Generation

Fingerprinting Redox Heterogeneity in Electrodes during Extreme Fast Charging

2019 ◽  
Author(s):  
Aashutosh Mistry ◽  
Francois L. E. Usseglio-Viretta ◽  
Andrew Colclasure ◽  
Kandler Smith ◽  
Parth Mukherjee
Keyword(s):  
Mass Transport ◽  
Heat Generation ◽  
Early Onset ◽  
Short Range ◽  
Lithium Ion ◽  
Redox Activity ◽  
Spatial Correlations ◽  
Fast Charging ◽  
Fast Transients ◽  
Erroneous Interpretation

Conventionally, battery electrodes are rationalized as homogeneous reactors. It proves to be an erroneous interpretation for fast transients, where mass transport limitations amplify underlying heterogeneities. Given the lack of observability of associated fast spatiotemporal dynamics, redox activity in inhomogeneous electrodes is superficially explored. We resort to a physics-based description to examine extreme fast charging of lithium-ion battery electrodes. Representative inhomogeneity information is extracted from electrode tomograms. We discover such electrodes to undergo preferential intercalation, localized lithium plating and nonuniform heat generation as a result of distributed long- and short-range interactions. The spatial correlations of these events with the underlying inhomogeneity are found to be nonidentical. Investigation of multiple inhomogeneity fields reveals an exponential scaling of plating severity and early onset in contrast to the homogeneous limit. Anode and cathode inhomogeneities couple nonlinearly to grow peculiar electrodeposition patterns. These mechanistic insights annotate the complex functioning of spatially nonuniform electrodes.

Modeling Heat Generation in a Lithium Ion Battery

2011 ◽  
Author(s):  
Wei Wu ◽  
Xinran Xiao ◽  
Xiaosong Huang
Keyword(s):  
Heat Generation ◽  
Numerical Study ◽  
Lithium Ion ◽  
Local Heat ◽  
Generation Rate ◽  
Generation Model ◽  
Heat Generation Rate ◽  
Battery Cell ◽  
Discharge Rates ◽  
Generation Mechanisms

This paper presents a numerical study on heat generation in a lithium-ion (LiC6/LiPF6/LiyMn2O4) battery cell. The numerical model considered multi-physics including battery kinetics, diffusion, and thermal analysis. The heat generation rate was determined by a local heat generation model. This model enables the investigation of the effects of battery parameters on different heat generation mechanisms and the overall heat generation rate in the battery. The effects of the thickness of the battery components and the size of the electrode particles at different discharge rates were evaluated. The results revealed the relationships between these parameters. A battery with a low heat generation rate and efficient battery utilization may be achieved through parameter optimization.

Reduction of oxygen to peroxide in a trickle electrode

1989 ◽  
Vol 54 (6) ◽  
pp. 1564-1574 ◽  
Author(s):  
Otomar Špalek ◽  
Karel Balogh
Keyword(s):  
Particle Size ◽  
Current Efficiency ◽  
Electrode Material ◽  
Pressure Loss ◽  
Peroxide Formation ◽  
Liquid Holdup ◽  
Electrolyte Flow ◽  
Electrode Thickness ◽  
Material Particle ◽  
Flow Rates

The effects of the electrode material particle size, electrode thickness, diaphragm properties and gas and electrolyte flow rates on the pressure loss and liquid holdup in the electrode and on the current efficiency of peroxide formation by oxygen reduction were studied in a trickle electrode. The results are discussed using trickle-bed electrode calculations.

Reduced Order Impedance Models of Lithium Ion Batteries

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Githin K. Prasad ◽  
Christopher D. Rahn
Keyword(s):  
Lithium Ion Batteries ◽  
Transfer Functions ◽  
Electrochemical Impedance ◽  
Active Material ◽  
Lithium Ion ◽  
Particle Model ◽  
Simulation Design ◽  
Material Particle ◽  
Reduced Order ◽  
Cell Parameters

This paper develops reduced order, linear models of lithium ion batteries that can be used for model-based power train simulation, design, estimation, and controlling in hybrid and electric vehicles (HEV). First, a reduced order model is derived from the fundamental governing electrochemical charge and Li+ conservation equations that are linearized at the operating state of charge and low current density. The equations are solved using analytical and numerical techniques to produce the transcendental impedance or transfer function from input current to output voltage. This model is then reduced to a low order state space model using a system identification technique based on least squares optimization. Given the prescribed current, the model predicts voltage and other variables such as electrolyte and electrode surface concentration distributions. The second model is developed by neglecting electrolyte diffusion and modeling each electrode with a single active material particle. The transcendental particle transfer functions are discretized using a Padé Approximation. The explicit form of the single particle model impedance can be realized by an equivalent circuit with resistances and capacitances related to the cell parameters. Both models are then tuned to match experimental electrochemical impedance spectroscopy (EIS) and pulse current-voltage data.

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