Thermal Characteristics and Safety Aspects of Lithium-Ion Batteries: An In-Depth Review

This paper provides an overview of the significance of precise thermal analysis in the context of lithium-ion battery systems. It underscores the requirement for additional research to create efficient methodologies for modeling and controlling thermal properties, with the ultimate goal of enhancing both the safety and performance of Li-ion batteries. The interaction between temperature regulation and lithium-ion batteries is pivotal due to the intrinsic heat generation within these energy storage systems. A profound understanding of the thermal behaviors exhibited by lithium-ion batteries, along with the implementation of advanced temperature control strategies for battery packs, remains a critical pursuit. Utilizing tailored models to dissect the thermal dynamics of lithium-ion batteries significantly enhances our comprehension of their thermal management across a wide range of operational scenarios. This comprehensive review systematically explores diverse research endeavors that employ simulations and models to unravel intricate thermal characteristics, behavioral nuances, and potential runaway incidents associated with lithium-ion batteries. The primary objective of this review is to underscore the effectiveness of employed characterization methodologies and emphasize the pivotal roles that key parameters—specifically, current rate and temperature—play in shaping thermal dynamics. Notably, the enhancement of thermal design systems is often more feasible than direct alterations to the lithium-ion battery designs themselves. As a result, this thermal review primarily focuses on the realm of thermal systems. The synthesized insights offer a panoramic overview of research findings, with a deeper understanding requiring consultation of specific published studies and their corresponding modeling endeavors

Thermal Analysis of Cold Plate with Different Configurations for Thermal Management of a Lithium-Ion Battery

Thermal analysis and thermal management of lithium-ion batteries for utilization in electric vehicles is vital. In order to investigate the thermal behavior of a lithium-ion battery, a liquid cooling design is demonstrated in this research. The influence of cooling direction and conduit distribution on the thermal performance of the lithium-ion battery is analyzed. The outcomes exhibit that the appropriate flow rate for heat dissipation is dependent on different configurations for cold plate. The acceptable heat dissipation condition could be acquired by adding more cooling conduits. Moreover, it was distinguished that satisfactory cooling direction could efficiently enhance the homogeneity of temperature distribution of the lithium-ion battery

Lead Doped Carbon Nanofibers in Li-ion Batteries

Lead acid batteries have been a very reliable rechargeable battery since its inception in the mid-1800s. Lithium-Ion batteries have been sought out for their light-weight and capacity of holding large amounts of energy in a small amount of space. Few studies have been conducted in the use of lead in lithium-ion batteries. In this thesis, lead-doped carbon nanofibers were produced by using the Forcespinning® method and used as an anode on a lithium-ion battery. The morphology, material characterization and thermal properties of the anode material were analyzed using the Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Thermogravimetric Analysis (TGA) and X-Ray Photoelectron Spectroscopy (XPS). Electrochemical studies on the batteries cells were cycle performance, cyclic voltammetry and rate performance

Failure mechanicms in overdischarged and overcharged lithium-ion batteries

Lithium-ion batteries are employed in applications as varied as consumer electronics, electric vehicles, satellites, and airplanes. As lithium-ion battery systems are increasingly scaled to large systems, safety and reliability are paramount. Catastrophic failure of a lithium-ion battery can cause damage to the host system and pose a risk to human life. While many lithium-ion batteries degrade in a benign fashion, others can enter into thermal runaway, generate gas within the battery, and catch fire and/or spontaneously disassemble. Determining precursors to catastrophic failure will allow for early failure mitigation strategies that can reduce the effects of a thermal runaway or prevent it from occurring in the first place. This research will identify several critical factors affecting performance and safety in lithium-ion batteries that are exposed to overdischarge or overcharge abuse. Lithium-ion batteries that are operated outside of their intended voltage range can experience both performance and safety degradation. Operation at voltages below the battery manufacturer’s recommended lower voltage limit results in overdischarge. Overdischarge of lithium-ion batteries can lead to copper dissolution, and the use of X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) analysis combines surface- and bulk-level analysis to characterize the risk of short circuit due to copper dissolution and re-precipitation. Operation at voltages above the battery manufacturer’s recommended upper voltage limit results in overcharge. Overcharge initiates exothermic reactions within the battery that can lead to thermal runaway. Furthermore, gas is generated during these side reactions, causing pressure buildup within lithium-ion cells as they undergo abuse. Pressure evolution is measured and a model developed to explain the relationship between state of charge, temperature, and internal cell pressure

Acoustic and X-ray Chacterisation of Lithium-Ion Battery Failure

Lithium-ion batteries have become synonymous with modern consumer electronics and potentially, are the cornerstone to development of integrated electrified infrastructure that can support a clean and renewable national energy grid. Despite the widespread applications due to the favourable performance parameters, recent events have elevated the safety concerns associated with lithium-ion batteries. However, there is great difficulty in rapid diagnostic analysis outside specialised laboratories which can hinder the review of functional safety- and novel energy dense- materials for lithium-ion energy storage. The dynamic evolution of internal architectures and novel active materials across multiple length scales are investigated in this thesis; with in-situ and operando acoustic spectroscopy (AS) via ultrasonic time of flight (ToF) probing, high speed synchrotron X-ray imaging, computed tomography and fractional thermal runaway calorimetry. The identification of characteristic precursor events such as gas-induced delamination in degradation mechanisms before eventual failure by AS; is correlated with X-ray imaging and post-mortem computed tomography (CT), highlighting the potential for battery management systems. Mitigation and prevention of failure with plasticized current collectors and thermally stable cellulose separators was also investigated at multiple length scales, with the transient mechanical structure compared with their commercial counterparts in cylindrical cells. Further work investigating the robustness of acoustic spectroscopy and polymer current collectors were applied to pure silicon nanowire negative electrodes. The studies reported in this thesis assess novel materials in lithium-ion batteries, and the potential impact of the work is highlighted. Development of AS via ToF probing offers another unique and field deployable insight allowing more complete and comprehensive understanding of batteries as they continue to evolve in complexity. Lithium-ion failure characterisation techniques and literature have evolved and provided insights into the function of polymer current collectors in different cell formats and chemistries. Findings presented in this thesis are anticipated to augment future inherently safer battery design and characterisation of lithium-ion energy storage thermal runaway

Thermal Modeling of Lithium-Ion Energy Storage Systems for Hybrid Electric Vehicles Using Computational Fluid Dynamics with Conjugate Heat Transfer

The success and performance of a Hybrid Electric Vehicle (HEV) relies largely on its Energy Storage System (ESS). High temperatures and thermal variations can significantly affect a battery\u27s performance and lifecycle. An effective thermal management system is vital to the health and safe operation of the ESS\u27s batteries. A well designed thermal management system begins with the accurate prediction of the battery\u27s thermal conditions. In hot climates, HEVs may be required to operate within ten degrees Celsius of the maximum safe operating temperature of their batteries. This study aims to evaluate the thermal management system of a lithium-ion based energy storage system designed for HEV applications. The analysis uses estimated current values from powertrain simulation software, fundamental heat transfer principles, finite element analysis (FEA), and computational fluid dynamics (CFD) tools to predict the temperature distributions in battery modules

Multiphysics analysis of electrochemical and electromagnetic system addressing lithium-ion battery and permanent magnet motor

Lithium-ion batteries are the leading energy storage technology in the electronic-driven society. With the need for portable, long-life electronics the demand for lithium batteries has escalated over the decade. Lithium-ion batteries show remarkable electrochemical characteristics, including but not limited to, long cycle-life, high cut-off voltages and high energy-density. However, lithium-ion cells are problematic to design due to their inherent thermal and/or mechanical instability. The objective of the current research framework is to establish the criteria causing thermo-mechanical failure of the battery systems, material properties effecting the performance, and model cycle-life degradation due to electrolyte loss by solid electrolyte interface (SEI) formation. An extension of this thermo-mechanical analysis was performed on electromagnetic system. A FEM was performed for a 20W BLDC motor to predict the electromagnetic and thermo-mechanical performance under steady state operating conditions. In our present research, we have studied the mechanical and thermal aspect of lithium battery electrodes. The first and second project encapsulated the material selection aspect for thermo-mechanically stable lithium battery electrodes. The objective of these projects was to develop a set of material indices (five for mechanical and five for thermal) which compare the performance of electrode materials based on heat generation, diffusion and mechanical strength and toughness. A mathematical model was formulated to determine particle deformation and stress fields based upon an elastic-perfectly plastic constitutive response. Mechanical deformation was computed by combining the stress equilibrium equations with the electrochemical diffusion of lithium ions into the electrode particle. The result provided a time developing stress field which shifts from purely elastic to partially plastic deformation as the lithium-ion diffuses into the particle. For the mechanical integrity, the materials were tested for strength, and toughness under elastic and plastic deformation. The model was used to derive five merit indices that parametrize mechanical stability of electrode materials. The five indices were used to analyze the mechanical stability for the six candidate electrode materials – graphite, silicon, and titanium oxide for the anode and lithium manganese oxide, lithium cobalt oxide and lithium ferrous phosphate for the cathode. Finally, the work suggested ways to improve the mechanical performance of electrode materials and helps to identify mechanical and design properties that need to be considered for optimal electrode material selection. Materials were selected based upon high strength and toughness with the ability to handle faster charging capabilities. A coupled thermo-chemical model was developed and used for deriving the heat generation by electrode particle of different materials. The thermal merit index analysis was based on performing a multivariable material selection based on four mechanisms of thermal generation against the thermal diffusion characteristics of the electrode material. A new mode of heat generation was conceptualized plausible for fast charging electrode materials. The heat generated by this mechanism accounted for the strain energy dissipated due to plastic deformation of the electrode particles upon lithiation. A parametric analysis was conducted to compare the thermal performance of six candidate electrode materials (for cathode and anode) using the merit indices and the results were validated against past experimental data. The effect of variable charging rates on thermal generation was analyzed. Finally, the paper identified the material properties which affect the thermal performance of battery systems. The thermo-mechanical material indices were designed to be a tool or platform for industries and experimentalists to compare new with existing electrode materials and isolate the material properties that need to be altered for better performance of the battery. The third project undertaken was to work on the concept of structurally integrable and mechanically robust lithium-ion pouch cells applicable for hybrid electric vehicles. Branching out from the focus area of flexible lithium batteries, a structurally stable cell could be integrated with the body of the vehicle, thereby eliminating the additional weight and support needed to install a battery pack. The analysis involves the conceptualization of the lithium-ion separator membrane as an open-cell foam under compression and the decrement in the ionic-conductivity was modelled analogous to the permeability loss in a foamy material. The thermal profiling for three different lithium-ion cells (LCO/C, (lithium manganese oxide) LMO/C and LFP/C) were simulated with five separator materials under variable applied load, rates of charging and cooling conditions. A set of thermal maps were created to demarcate the domains of thermal meltdown of the separator membrane and the conditions leading up to the thermal runaway. The proposed model could be used as a design tool for industrial application of structurally flexible lithium-ion pouch cell to predict thermally safe lithium battery, thereby reducing the risks and loss from battery meltdown during prototyping. The fourth project undertook the modeling of battery degradation and life prediction due to SEI growth resulting into capacity fading. An efficient reduced-order electrochemical model was developed for lithium cobalt oxide (LCO)/graphite (C) pouch cell and a reaction-diffusion based SEI model was integrated to predict the cyclic capacity loss due to electrolyte deposition over the anode in the form of SEI. The experimental data was fitted based on a single-parameter fit to predict the reaction coefficient for SEI current. The algorithm developed for this battery module was designed to reduce the computational time for capacity fade calculation. The model was also applied for a lithium ferrous phosphate (LFP)/C cell without any fitting, and in both cases the predictions were within ±1% deviation from the experimental results, thereby predicting capacity fading for different cathode materials with graphite as the anode. A novel concept was developed in which “aged-battery” could be used as an advantage for biomedical and EV applications. The fading rate decays as the cell ages and aged-cells could be operated for longer life cycles with negligible fading. A cost analysis was performed to find the optimized point where the benefits from lower fading was weighed against the cost (material and electricity) involved in ageing the cell. The application for this concept would be in biomedical and EV industries, where the replacement of lithium-ion batteries over short periods of time is not feasible and the cost/risk of replacement exceeds the cost of ageing the battery. Aging the cell could prolong its cycle life thereby reducing the chances of battery replacement in a long duration of operation. The fifth project undertook a small project to compare the prediction of thermal conductivity by different approaches of Boltzmann Transport Equations. The lattice thermal conductivity predictions for a silicon nanoparticle was performed using three popular formulations of the Boltzmann transport equation. The models as proposed by Klemens, Callaway and Holland, essentially differ in the phonon scattering mechanisms and the vibrational modes considered in the respective formulations. At low temperatures, results from all three models showed strong agreement with experimental measurements but deviated significantly with increasing temperatures. Estimates from the Holland model, which explicitly accounted for the normal and Umklapp scattering processes of the transverse and longitudinal modes, concur with the measured values. Similar predictions were obtained from both Holland and Callaway models at high temperatures since phonon transport was dominated by longitudinal modes, as revealed from our analyses of the relaxation times. In conclusion, the paper inferred the importance of mode dependent thermal conduction in silicon nanoparticle at elevated temperatures. The final work done was to model a 20W BLDC motor with bonded magnets used as the surface permanent magnet for the rotor. A thermo-mechanical and electromagnetic analysis was performed to test the application of the 65 vol.% bonded NdFeB magnets in a motor. The performance analysis involved the prediction thermo-mechanical properties for the bonded magnets and redesign of the motor to operate at safe thermal and mechanical limits. The design was finalized and considered for prototyping as a part of the demonstration for the project. In conclusion, a thermo-mechanical multiphysics analysis and material selection was performed primarily for electrochemical and extended to electromagnetic systems to predict performance, mechanism of degradation and cycle life under variable operating conditions. These model act as tools and design guide to aid in the development of lithium-ion batteries and electromagnetic drives. The purpose of modeling and material selection is to reduce the cost of experimentation and prototyping prior to commercialization. The multiphysics modeling performed also isolates the parameters which effect the health and safety of the system, thereby reducing the risks of failure during operation. Therefore, selection of the correct design parameters and models to support the performance and life predictions allow a rapid and economic transition from prototyping to commercialization of electrochemical and electromagnetic systems

Improved thermal performance of a large laminated lithium-ion power battery by reciprocating air flow

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Thermal safety issues are increasingly critical for large-size laminated Lithium-Ion Batteries (LIBs). Despite a number of investigations conducted on the Battery Thermal Management System (BTMS) with reciprocating air-flow cooling, large laminated power LIBs are still not sufficiently investigated, particularly in the view of battery thermal characteristics. The present study investigates the thermal behaviors of an air-cooled NCM-type LIB (LiNi1−x−yCoxMnyO2 as cathode) from an experimental and systematic approach. The temperature distribution was acquired from different Depth of Discharge (DOD) by the infrared imaging (IR) technology. A reciprocating air-flow cooling method was proposed to restrict the temperature fluctuation and homogenize temperature distribution. Results showed that there was a remarkable temperature distribution phenomenon during the discharge process, the temperature distribution was affected by direction of air-flow. Forward air-flow (from current collector side to lower part of battery) was always recommended at the beginning of the discharge due to the thermal characteristics of the battery. After comprehensive consideration on battery temperature limit and cooling effect, the desired initial reversing timing was about 50% DOD at 3 C discharge rate. Different reversing strategies were investigated including isochronous cycles and aperiodic cycles. It was found that the temperature non-uniformity caused by heat accumulation and concentration was mitigated by reciprocating air-flow with optimized reversing strategy

Infrared imaging investigation of temperature fluctuation and spatial distribution for a large laminated lithium ion power battery

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The present study investigates the thermal behaviors of a naturally cooled NCM-type LIB (LiNi1−x−yCoxMnyO2 as cathode) from an experimental and systematic approach. The temperature distribution was acquired for different discharge rates and Depth of Discharge (DOD) by the infrared imaging (IR) technology. Two new factors, the temperature variance ( ) and local overheating index (LOH index), were proposed to assess the temperature fluctuation and distribution. Results showed that the heat generation rate was higher on the cathode side than that on the anode side due to the different resistivity of current collectors. For a low-power discharge, the eventual stable high-temperature zone occurred in the center of the battery, while with a high-power discharge, the upper part of the battery was the high temperature region from the very beginning of discharge. It was found that the temperature variance ( ) and local overheating index (LOH index) were capable of holistically exhibiting the temperature non-uniformity both on numerical fluctuation and spatial distribution with varying discharge rates and DOD. With increasing the discharge rate and DOD, temperature distribution showed an increasingly non-uniform trend, especially at the initial and final stage of high-power discharge, the heat accumulation and concentration area increased rapidly

Biomass-derived carbon materials for energy storage applications

Energy storage systems are an essential link in the implementation of renewable energies and in the development of electric vehicles, which are needed to reduce our dependence on fossil fuels and the emission of greenhouse gases. Various technologies have been proposed for energy storage based on different working principles, including lithium-ion batteries, emerging sodium-ion batteries and electric-double layer capacitors. Besides the quest for improving key aspects such as energy and power densities, current research efforts are devoted to foster the manufacturing of more environmentally friendly devices using sustainable materials. Carbon-based electrodes hold considerable promise in such terms due to their low cost, tailorable morphology and microstructure, and the possibility of processing them by direct carbonization of eco-friendly and naturally-available biomass resources. The main goal of this thesis is to develop carbon materials from biomass resources and study their applications as electrode for lithium-ion batteries, sodium-ion batteries and electric-double layer capacitors. En route towards that goal, it also aims at expanding our understanding of the microstructural changes of biomass-derived carbons with varying processing conditions and their effect on the electrochemical performance for each of these technologies. The first part of this work reports on the synthesis of graphitized carbon materials from biomass resources by means of an Fe catalyst, and the study of their electrochemical performance as anode materials for lithium-ion batteries (LIBs). Peak carbonization temperatures between 850 °C and 2000 ºC were covered to study the effect of crystallinity, surface and microstructural parameters on the anodic behavior, focusing on the first-cycle Coulombic efficiency, reversible specific capacity and rate performance. Reversible capacities of Fe-catalyzed biomass-derived carbons were compared to non-catalyzed hard carbon and soft carbons materials heated up to 2800 ºC. Moreover, in-situ characterization experiments were carried out to advance our understanding of the mechanisms responsible for catalytic graphitization. The second part of this work reports a comprehensive study on the structural evolution of hard carbons from biomass resources as a function of carbonization temperature (800 - 2000 ºC), and its correlation with electrochemical properties as anode materials for sodium-ion batteries (SIBs). Synchrotron X-ray total scattering experiments were performed and the associated atomic pair distribution function (PDF) extracted from the data to access quantitative information on local atomic arrangement in these amorphous materials at the nanoscale, as well as its evolution with increasing processing temperature. Then, electrochemical properties and the storage mechanisms involved on Na ions insertion into hard carbon structures at each characteristic potential regions were elucidated and correlated with microstructural properties. Finally, the third part of this work reports on the synthesis of nanostructured porous graphene-like materials from biomass resources using an explosion-assisted activation strategy by nitrate compounds and Ni as a graphitization catalyst. The thermal behavior during carbonization as well as the resulting microstructural and surface properties were evaluated at two different processing temperatures, 300 and 1000 ºC. Finally, their application as electrode materials for electric-double layer capacitors (EDLCs) and LIBs is investigated, with a view to their performance under high charge/discharge specific current densities experiments.Premio Extraordinario de Doctorado U