SAFER LI-ION BATTERIES THROUGH BETTER THERMAL MANAGEMENT

Lithium-ion battery packs are essential to the electrification of cars, especially electric vehicles (EVs), as they provide the required energy storage for longer driving distances and improved performance. The performance and design trends for Li-ion battery packs for electric vehicles are presented in this article in detail. This review paper examines the contemporary movements in the boundaries of Li-ion battery technology for EV applications, which involve a range of factors, such as design specifications of a battery pack and other safety measures, the importance of battery management systems (BMS), and thermal management systems (TMS). The design levels of Li-ion battery packs are discussed based on a selection of the right cells and application criteria, which include the weight of the battery in an electric vehicle (EV) and the placement of the battery in the vehicle, which can affect the handling and power efficiency of the vehicle. Moreover, the Li-ion battery intelligence system, referred to as the Battery Management System (BMS), is extensively discussed, including its architecture, functions, and conventional and advanced optimized algorithms to protect and mitigate battery failures. The reliability of precise estimation of state-of-charge and cell balancing is investigated, which integrates with artificial intelligence and machine learning techniques. In this article, the temperature consequences of Li-ion batteries during internal and external fault operating conditions investigated, and various advanced battery thermal management systems emphasized to prevent thermal runaway in EV applications. The research results provide a roadmap for academics, engineers, and other industry participants to comprehend and traverse the rapidly developing field of battery technology, fostering the development of effective, secure, and environmentally friendly energy storage options for electric vehicles.

Design and simulation of a lithium-ion battery with a phase change material thermal management system for an electric scooter

Recent advancement and enhanced battery performance using phase change materials based hybrid battery thermal management for electric vehicles

<div class="section abstract"><div class="htmlview paragraph">Lithium-ion (Li-ion) batteries have become a research focus in the field of electric and hybrid electric vehicles, due to key advantages such as high specific energy, high energy density and low self-discharge rate in comparison with other battery technologies. Nevertheless, key issues involving safety, performance, cost, charging time and durability restrict mass market adoption of electric vehicles. Cold-temperature operation of Li-ion batteries is currently a subject of major research efforts. The effects of low temperature reduce the available energy of the battery and increase its internal impedance. Moreover, Li-ion batteries experience serious degradation mechanisms at low temperatures, strongly affecting performance, which poses difficulties for cold-climate countries. In this work, a battery-in-the-loop experiment has been set up to estimate and analyze Li-ion battery cold start ranges at temperatures down to -40 °C. This experimental setup is connected to the open integration and test platform CarMaker from IPG Automotive to evaluate cold start range both through standardized automotive duty cycles and within a virtual test environment designed to replicate real-world test driving. In addition, a non-isothermal equivalent circuit battery model has been developed in CarMaker for Simulink and validated against experimental data. Effects of cold temperatures on the capacity and power fade of Li-ion battery technology are studied, as well as important thermal aspects, including effects of changing battery heat transfer coefficient to replicate different thermal management strategies. Range discrepancies between standardized duty cycles and a representative driving environment are also explored. Overall, this work contributes to identify key improvements in Li-ion battery thermal management for performance and durability enhancement during cold start.</div></div>

Significant improvements in thermal management technologies will be required to support NASA’s planned Lunar and Mars missions. The developments needed include the application of advanced materials to reduce radiator system masses, enhanced survivability, and the use of alternative working fluids. Current thermal management systems utilize one of two heat rejection alternatives; either single phase pumped loops, or two phase heat pipes constructed with thick walled metal casings. These two technologies have proven themselves to be reliable performers in the transport and rejection of waste heat from spacecraft. As thermal management needs increase with increased power consumption and activity required on spacecraft, these metal based thermal management systems will become mission limiting. Investigations into the use of light weight ceramic materials for high temperature thermal management systems have been conducted by NASA, the Department of Energy, and the Department of Defense since the early 1980s, with results showing that significant mass savings can be obtained by replacing some of the metallic functions with ceramic materials.

With the development of hybrid electric vehicles and electric vehicles, more and more attention has been paid to Li-ion batteries. Since the charge-discharge performances of Li-ion batteries are affected by the temperature, an effective thermal management system is the key to solve the problem. Therefore, it is necessary to establish different simulation models to simulate the effects of the various thermal management systems. The prismatic pouch Li-ion batteries cell is composed of multiple cell units connected in parallel, to reduce the calculation, the simplified models are used to simulate the Li-ion batteries. In this paper, one detailed model and two simplified models are established to simulate temperature uniformity of heating Li-ion batteries cells, and heating methods are the self-heating Li-ion batteries structure heating method and the wide-line metal film heating method. The simulation results of the detailed model and two simplified models are compared and analyzed. The results show that there are difference between the detailed model and two simplified models about temperature difference of the Li-ion batteries cell, and the two simplified models have the same simulation results. Finally, the simulation results of the detailed models with different footprint areas are compared. The comparison results show that different footprint areas have no effect on the simulation results for both the self-heating Li-ion batteries structure heating method and the wide-line metal film heating method.

Three dimensional (3D) integration offers numerous electrical advantages like shorter interconnection distances between different dies in the stack, reduced signal delay, reduced interconnect power and design flexibilities. The main enabler of 3D integration is through-silicon-vias (TSVs) and stacking of multiple dies. Irrespective of these advantages, thermal management in 3D stacks poses significant challenges for the implementation of 3D integrated circuits. Even though extensive research work has been done in understanding the thermal management in two dimensional (2D) planar circuits for the past several decades, 3D integration offers a new set of challenges in terms of thermal management, which makes it difficult to readily apply the thermal management strategies available for 2D planar circuits. Over the past decade, some work has been done in thermal analysis and management of 3D stacks but still, knowledge is scattered and a comprehensive understanding is lacking. This research work focuses on bringing together the limited work on thermal analysis and thermal management in 3D vertically integrated circuits available in the literature. A compilation and analysis of the results from investigations on thermal management in 3D stacks is presented in this review with special emphasis on experimental studies conducted on different thermal management strategies. Furthermore, 3D integration technologies, thermal management challenges, and advanced 2D thermal management solutions are discussed.

While the high energy densities and long cycle lifetimes of Li-ion batteries have enabled them to become an important form of energy storage, these properties are greatly diminished at lower temperatures.1 The battery electrolyte plays a key role in these performance reductions as many processes involving Li+ transport kinetics are negatively impacted by low temperatures.2 To mitigate the effects of operating Li-ion batteries in cold environments, researchers have put considerable effort into designing thermal management systems to prevent batteries from operating outside their optimized temperatures.3 While extensive work has been performed to understand and limit the effects of low temperatures on Li-batteries during operation, limited information exists on passive battery exposure to cold environments, particularly at more extreme temperatures where solidification of the electrolyte can occur. Thus, we employ micro-Raman spectroscopy to characterize the temperature-dependent, solidification dynamics of commercial, carbonate-based electrolytes (1 M LiPF6 in varied ratios of ethylene carbonate (EC) and dimethyl carbonate (DMC)). During electrolyte cooling, phase transitions for EC and DMC are observed which induce spatial heterogeneity in the electrolyte composition whereby some regions become solidified while others remain liquid with elevated concentrations of LiPF6. Such changes in the electrolyte composition may impact Li-ion batteries stored at low temperatures as well as batteries utilized in space applications where thermal management is transiently unavailable and may even impact batteries operated in cold environments in addition to the reductions in other temperature-dependent properties.References Petzl, M.; Kasper, M.; Danzer, M. A. Lithium plating in a commercial lithium-ion battery – a low-temperature aging study. J. Power Sources 2015, 275, 799–807.Hubble, D.; Brown, D. E.; Zhao, Y.; Fang, C.; Lau, J.; McCloskey, B. D.; Liu, G. Liquid electrolyte development for low-temperature lithium-ion batteries. Energy Environ. Sci. 2022, 15, 550–578.Kim, J.; Oh, J.; Lee, H. Review on battery thermal management system for electric vehicles. Appl. Therm. Eng. 2019, 149, 192–212.

Lithium-ion (Li-ion) batteries have recently become the main source of power in portable devices due to advantages such as high energy density. However, Li-ion cells operate well only in a specific temperature range. Degraded preperformance is a consequence of low temperature operation, and potential fire risk originates from thermal runaway at elevated temperatures. Efficient thermal management of Li-ion cells and battery packs is essential to ensure safe and durable performance in wide temperature range. Thermoelectric coolers (TECs), which have been used widely for electronics cooling may also be appropriate for battery cooling due to size compactness, working with direct current. This paper presents experimental characterization of cooling of a prismatic test cell with TECs on two sides. Cooling effect of TEC on the cell core and surface temperatures is investigated at different TEC power rates. Results show core and surface temperatures of the test cell decrease significantly. The obtained results show that by applying the TEC, a temperature drop of 10 °C was achieved for 0.75A TEC current. The optimum TEC current can be selected based on the application. In addition, numerical simulations are carried out to compare with experimental measurements. Heating effect of mounted TECs can be easily achieved just by changing current direction. Experimental results reveal TECs can heat up a cell in cold climate shortly. In addition, thermo electric module may also offer insulating effect in cold climate. Results presented in this paper illustrate potential application of thermoelectric cooling for thermal management of Li-ion cells.

Liquid hydrogen storage, thermal management, and transfer-control system for integrated zero emission aviation (IZEA)

For the last two decades rechargeable Li-ion batteries (LIBs) have been widely used in portable electronic devices owing to their peculiar characteristics such as high gravimetric and volumetric energy. In fact, LIBs are considered the most suitable candidates for hybrid (HEV) and electric vehicles (EV) [1-3]. However, towards the employment of Li-ion batteries into HEV/EV, a substantial improvement in energy and power density of the electrode materials is needed. In particular, at the anode side, the present Li-ion battery technology is mostly based on graphite anodes, providing a 372 mAh/g lithium storage capacity.In this regard, both Silicon and Germanium are excellent candidates as active anodes for LIBs owing to their high lithium storage capability, that is 4200 and 1620 mAh g-1, respectively [1,4]. Although Ge, owing to the drawback of its expensiveness, was in the recent past attracting considerably less attention than Si, it is now undergoing an increase in popularity because of its desirable advantages such as high intrinsic electrical conductivity (104 times higher than silicon) and higher capacity than graphite anodes. Furthermore, it has been reported that the lithium diffusion into Ge is 15 and 400 times faster than in Si at 360o C and at room temperature, respectively [1,5]. This ensures higher rate capability and more efficient charge transport than in silicon and graphite as well, fundamental properties in advanced high power density applications such as hybrid electric vehicles. However, similarly to silicon, the lithiation of Ge anode during cycling undergoes dramatic volume changes (~ 300%), which leads to pulverization and capacity fading in bulk. One of the most successful techniques to overcome the aforementioned problem and to improve the performance of LIBs, is the reduction of Ge size to the nanoscale.Here, we report about a novel synthesis method to produce Ge nanocrystals through solvothermal approach (200-300 oC), with size in 5-10nm range, used as anode in lithium ion batteries. The novelty lies in the simplicity of the proposed approach in fact, differently from standard processes [6], non-hazardous reducing agents were used and, at the same time, there is no longer need of maintaining inert atmosphere conditions. In particular, our approach starts from Germanium halogen GeX (X= Cl2, I2) salts. The Ge nanocrystals have been characterized with X-ray diffraction, X-ray photoelectron spectroscopy, scanning (SEM) and transmission (TEM) electron microscopies. Figure 1 shows the X-ray diffraction pattern of Ge nanocrystals with JCPDS card No. 03-065-0333 together with the TEM image of Ge nanocrystals. The latter demonstrates a good uniformity in the nanocrystals dimensions, falling in the range between 5nm and 10nm. Finally, the electrochemical investigation of lithium insertion/de-insertion of these nanocrystals have been studied with cyclic voltammetry, A.C impedance and galvanostatic charge-discharge measurements.

Lithium-ion batteries were first commercialized more than 25 years ago, and today are ubiquitous components in a wide range of applications, including personal electronics, the transportation industry, defense and space applications. As with many energy storage devices, there is a continuous push to create more efficient, better performing, and safer Li-ion batteries. While building and testing new Li-ion batteries is crucial to continued development and improvement, mathematical modeling also plays an extremely important role. Mathematical modeling can reduce the time and materials cost of battery development, and can lead to a better understanding of the fundamental parameters that affect battery performance. This article traces the history of battery modeling, including the critical contributions provided by porous electrode theory some 50 years ago. The role that these early advances have in modeling Li-ion batteries is discussed. Finally, this article touches on the future direction of Li-ion battery modeling, including development of physics-based models to improve battery safety.

<div class="section abstract"><div class="htmlview paragraph">The transition towards sustainable transportation necessitates the development of advanced thermal management systems (TMS) for electric vehicles (EVs), hybrid electric vehicles (HEVs), hydrogen fuel cell vehicles (FCVs), and hydrogen internal combustion engine vehicles (HICEVs). Effective thermal control is crucial for passenger comfort and the performance, longevity, and safety of critical vehicle components. This paper presents a rigorous and comparative analysis of TMS strategies across these diverse powertrain technologies. It systematically examines the unique thermal challenges associated with each subsystem, including cabin HVAC, battery packs, fuel cell stacks, traction motors, and power electronics. For cabin HVAC, the paper explores methods for minimizing energy consumption while maintaining thermal comfort, considering factors such as ambient temperature, humidity, and occupant load. The critical importance of battery thermal management is emphasized, with a focus on preventing thermal runaway and maximizing battery lifespan through precise temperature regulation. The complexities of fuel cell stack thermal management are addressed, considering the electrochemical reactions and the need for uniform temperature distribution for optimal performance and durability. Furthermore, the paper investigates the thermal behavior of high-power traction motors and power electronics, analyzing different cooling techniques and their impact on efficiency and reliability. A comparative assessment of various cooling technologies, including forced air convection, liquid cooling, and emerging two-phase cooling methods, is provided. The paper also delves into integrating these individual TMS components, exploring opportunities for waste heat recovery and holistic system optimization. Finally, the paper identifies critical research gaps and outlines future directions in the development of intelligent and adaptive thermal management systems for next-generation electrified vehicles, emphasizing the need for robust control algorithms, advanced materials, and innovative cooling architectures.</div></div>

The advent of modern technology has led to a significant increase in the utilisation of rechargeable secondary batteries. Despite the sustainability of lithium-ion (Li-ion) batteries, the limited availability of lithium has driven research into alternative energy storage technologies. Sodium-ion (Na-ion) batteries, as a potential alternative to Li-ion batteries, have emerged as a highly promising contender. However, for these batteries to become industrially viable, certain properties such as energy and power density need to be enhanced. To address this issue, batteries have been a focus of research, and battery thermal management systems have been developed. These systems aim to evaluate battery performance, which is strongly influenced by temperature. Effective thermal management ensures that the battery operates within the optimal temperature range. This study models a pouch-type battery and evaluates the effects of phase changing materials (PCM) on battery temperature control. Comparative analysis is conducted using different PCMs to understand their impact. The study analyses the battery's response to specific temperature ranges and assesses how different PCMs affect battery cooling performance. The results provide critical insights for ensuring efficient battery operation. Furthermore, this research supports the broader adoption of Na-ion batteries in industrial applications and contributes to the development of sustainable energy storage systems.

Li-ion batteries are commonly used in portable electronic devices due to their outstanding energy and power density. However, in order to reach the requirements of the automotive industry for next-generation electric vehicles regarding safety, life-time, energy density, and fast charging further developments are inevitable. Additionally, a reduction of material and production costs is needed to improve the price competitiveness. In this contribution we will present a study of different electrode design concepts with the goal to optimize energy and power density of Li-Ion battery electrodes and cells by microstructure resolved electrochemical simulations [1]. State-of-the-art NMC positive electrodes with different thickness and density were prepared and characterized electrochemically in collaboration with our partners [2]. In a next step reconstructions of the electrodes were created with the help of synchrotron tomography and a 3D stochastic microstructure generator [3], [4]. The resulting microstructures are then input to electrochemical simulations within our software BEST and good qualitative agreement between the simulations and experimental data can be reported. Especially, the pivotal role of inactive materials for battery performance could be demonstrated through microstructure-resolved impedance simulations. Based on these results different design concepts were evaluated regarding their energy and power density. An attractive strategy to decrease the share of inactive materials is to increase the mass loading of the electrodes [5], [6]. This concept provides a high theoretical capacity and energy density. However, it also shifts the transport limitations of shuttling lithium ions in the electrolyte to lower C-rates and reduces the rate capability and practical capacity of the cell [6], [7]. In order to enable a fast charging of the batteries structuring techniques are investigated. A promising concept is the laser perforation of the electrodes which creates a hierarchical pore network with macroscopic transport pathways between anode and cathode. Our simulations confirm the beneficial effects which are found in the experiments and we perform an extensive simulation study in order to investigate the effect of different hole geometries and configurations on battery performance and life time. Our study shows that this simulation-based approach is a powerful and efficient tool for the analysis and design of porous electrodes for Li-ion batteries. Acknowledgement This work has been funded by the ‘Bundesministerium für Bildung und Forschung’ within the project HighEnergy under the reference numbers 03XP0073D.