Mingyi Chen

Jiangsu University · School of Environment and Safety Engineering

Adding flame retardant additives is an effective approach to improve the safety of lithium-ion battery electrolytes. This study discusses the inhibiting effects of three flame retardant additives on the combustion characteristics of electrolyte and carbonate mixed solvent under low pressure. The experimental results show that the inhibition of flam...

The thermal safety problem of lithium-ion batteries (LIB) in use requires an excellent thermal management system to preserve it. In the paper, an expansion flame-retardant composed of APP and CFA and kaolinite is used to enhance the flame-retardant property of phase change materials (PCM). The performances of PCM and their property in the thermal m...

Thermal runaway (TR) of lithium-ion batteries (LIBs) has always been the most important problem for battery development, and the TR characteristics of large LIBs need more research. In this paper, the thermal runaway propagation (TRP) characteristics and TR behavior changes of three lithium iron phosphate (LFP) batteries (numbered 1 to 3) under dif...

Given that many safety standards for lithium-ion cells include a saltwater immersion test and the possibility of cell immersion by water by accident, this work prepares five kinds of cells by varying immersion time and saltwater concentration to explore the influence of saltwater immersion on the topographic, electrochemical and thermal characteris...

Due to the lack of detailed comparison and reliability validation of paraffin (PA)-based optimization methods for lithium-ion thermal management systems, in this work, PA was selected as a phase change material (PCM). Both expanded graphite (EG) and the fin were used to optimize the thermal management performance of the PA. Charging and discharging...

The concept of immersion cooling has been proposed and validated via several numerical studies in recent years, while systematical experimental studies and corresponding theoretical considerations on its heat transfer mechanism are scarcely available in the literature. In this work, a series of experiments are conducted by means of a well-designed...

Although lithium-ion batteries are increasingly being used to achieve cleaner energy, their thermal safety is still a major concern, particularly in the fields of energy-storage power stations and electric vehicles with high energy-storage density. Therefore, the battery thermal management systems (BTMs) have been extensively applied, among which p...

Phase change material (PCM) cooling performs excellently in lithium-ion battery (LIB) thermal management. In order to improve the thermal conductivity of PCM, the new thermally-conductive composite phase change material (CPCM) was prepared with the paraffin wax (PA), expanded graphite (EG), and SiC/SiO2 by physical adsorption method. The structure...

A series of experiments were carried out in this study to investigate the sensitivity of lithium-ion batteries with different capacities to overcharge and over-discharge conditions; whereby, two nominal capacities (2100 and 3000 mAh) were included. It is observed that batteries experience a serious degradation in the process of overcharge cycling;...

The widespread use of lithium‐ion battery (LIB) urgently needs a thermal management system with excellent performance to manage it. Phase change material (PCM) has been adapted for thermal management of LIB because it can absorb a mass of energy without additional power. In this research, the thermal conductivity of PCM is improved, and its cooling...

In advanced battery thermal management systems for electric vehicles, liquid cooling (LC) is typically coupled with a phase-change material (PCM) cooling for secondary heat dissipation. However, a continuous LC consumes a considerable amount of energy without considering the operating conditions. In this study, the thermal behaviors of tubular PCMs...

Three types of cell samples (fresh cell, 60°C stored cell, and −10°C stored cell) were prepared to demonstrate the impact of abusive‐temperature storage on the topographic, electrochemical, and safety characteristics of lithium‐ion cells; besides that, the sensitivity of the three cell samples to typical abusive conditions is also discussed. In com...

The present work carries out a comparative study to illustrate the safety performance of two new-format cells (22650 and 26650) in the thermal runaway tests induced by over-heating and overcharge tests, referred by the traditional 18650 cells. In addition, a long-term cycling test is also performed to evaluate the electrochemical characteristics of...

When a lithium-ion battery is thermally out of control, the internal heat is mainly coming from the mutual reaction of the internal components of the battery. It is well known that the breakdown and combustion of carbonate solvents inside lithium-ion batteries contribute a large part of the heat when thermal runaway occurs. Therefore, it is necessa...

This work prepares five kinds of cell samples, i.e. the fresh cell, the cell degrades to 90% SOH (state of health) after high-temperature cycling, the cell degrades to 80% SOH after high-temperature cycling, the cell degrades to 90% SOH after low-temperature cycling and the cell degrades to 80% SOH after low-temperature cycling to reveal the electr...

Herein, a series of experiments were performed to illustrate the impact of safety vents on the evolution of thermal runaway behaviors of 18650-size lithium-ion batteries. Meanwhile, the effect of safety vents on the thermal safety of batteries with different states of charge (SOC), i.e. 0%, 50% and 100% and cathode chemistries, i.e. lithium nickel...

The overall performance of traction batteries deteriorate significantly at low temperatures (below 273.15 K). Therefore, it is vital to design a successful battery thermal management system (BTMS) to heat up the batteries and benefit the start-up of electric vehicles in cold geographical regions. In this study, a coupled heating method combining ph...

The present work carries out a series of thermal runaway experiments to explore the impact of charging and charging rate on the thermal runaway behaviors of lithium-ion cells, in which five charging rates (0C, 0.5C, 1C, 2C and 4C) and three initial states of charge (SOC), i.e. 25%, 50% and 75% are included. The thermal runaway process of 18650 lith...

Electrolytes are important parts of lithium-ion batteries, but traditional carbonate-based electrolytes have high flammability which could be an important source of heat generation in the thermal runaway process. The combustion characters of electrolyte and carbonate solvent based on three kinds of composite flame retardants are studied. The influe...

New strategy on alleviating battery fire without reducing energy density is studied. • Pioneering study on thermal runaway propagation under different gas dilutions. • X-ray CT images and energy-dispersive spectrometry reveal cell internal structures. • Different flame patterns under different oxygen levels are verified by theory. A R T I C L E I N...

Majority existing organic composite phase change materials (CPCMs) are flammable that result in thermal hazards such as fire and explosions in battery modules. Furthermore, the performance of PCM-based battery modules in extreme conditions like thermal runaway has not been studied adequately. In this study, a tubular CPCM-cell structure is designed...

Phase change materials (PCMs) are widely used in battery thermal management system (BTMS). Most previous research on BTMS has focused on single temperature environment or protocol, without verifying their effectiveness in volatile working environments, which affects battery heat accumulation and dissipation. In this study, a series of experiments i...

The mitigation of battery thermal runaway propagation remains challenging in the application of lithium-ion batteries, and safety enhancement remains a popular topic for battery thermal management. In this study, an aluminum honeycomb (AH) design module is proposed for a battery thermal management module, and its effects on TM and TR propagation ar...

Owing to increasing applications of lithium-ion batteries (LIBs), it is worth investigating the thermal runaway (TR) behaviors of LIBs under extreme conditions such as flash freezing, which has been proposed as a feasible way for LIB transportation or storage. In this study, a series of experiments was conducted to explore and compare the TR behavi...

Temperature is an important factor affecting the working efficiency and service life of lithium-ion battery (LIB). This study carried out the experiments on the thermal performances of Sanyo ternary and Sony LiFePO4 batteries under different working conditions including extreme conditions, natural convection cooling and phase change material (PCM)...

In order to investigate the thermal failure propagation behaviors of lithium batteries, a sequence of full-scale burning tests were conducted. The results showed that the average mass loss and total heat release of an individual cell are 5.8 g and 31.9 kJ, respectively. The battery pack fire exhibited intermittent propagation behaviors due to the h...

In this paper, the relation between headway and velocity in one and two-dimensional pedestrian flows is investigated by a series of controlled experiments. Three types of headway between two pedestrians from the same direction, opposite directions and cross directions are classified and calculated by using the proposed method. Two linear regimes in...

To better understand the boiling liquid expanding vapor explosions (BLEVE) risk in the fluorine chemical industry, the detailed BLEVE properties of 1,1-difluoroethane were investigated based on fire dynamics simulator code of computational fluid dynamics in this work. The BLEVE fireball was modeled using appropriate numerical models and parameters....

Considering the complexity of working environment and the sensitivity of lithium-ion batteries, a series of experiments are performed in the present work to investigate the impact of high-temperature environment on the optimal cycle rate of lithium-ion batteries. Two ambient temperatures (26 and 70 °C) and four cycle rates (0.5 C, 1 C, 2 C and 3 C)...

Because of the multi-layer structure and the diversified connection modes of most battery modules, systematically investigating the thermal failure propagation principles and mechanisms of lithium-ion batteries is critical to provide early warnings and protection for thermal runaway. In this work, a series of experimental studies and mathematical d...

In the current work, a series of experiments are carried out to investigate the degradation behavior of lithium‐ion batteries during overcharge cycling, as well as the influence of ambient temperature on the degradation. In which, different charge cut‐off voltages (4.5, 4.8, and 5.0 V) and ambient temperatures (0°C, 20°C, 50°C, and 70 °C) are inclu...

In view of the flammability of phase change materials (PCMs), a safer structure design for thermal insulation protection is crucial in a PCM-based battery thermal management system. In this work, a series of experiments is performed on battery modules with and without PCM and/or aerogel to investigate their heat dissipation capability and thermal i...

As an excellent option that has wide application in the thermal management system to ensure the safety of lithium-ion batteries, phase change material (PCM) cooling technology is highly desirable but the low thermal conductivity of PCMs limits its application. Herein, a series of experiments are conducted with and without fins to investigate the ef...

Downward sloping buoyant turbulent jet fires occur frequently during flammable gas leakage, while its flame trajectory, especially the quantitative length, is not well described. The flame trajectory lengths of downward jet fires with five sloping angles (0°, 15°, 30°, 45°, 60° relative to the horizontal) and two nozzle diameters (8 and 10 mm) were...

In this paper, the cone calorimeter is used to investigate the combustion characteristics of typical combustible components for lithium‐ion battery (LIB). The incomplete combustion of solvents, lithium salt, and separator results in the generation of residue. The melting of the separator at the early stage shows a more obvious endothermic reaction...

A set of experiments are performed in the present work to investigate the degradation behavior of lithium‐ion battery during overdischarge cycling, as well as the influence of a high‐temperature environment on the degradation. Among, different discharge cut‐off voltages (1.0, 0.5, and 0.2 V) are included. During the overdischarge process, batteries...

The environmental pressure effect on thermal runaway and fire behaviors in the 18650 lithium-ion battery (LIB) with various cathodes and states of charge (SOC) are experimentally investigated in this work. The fire hazards were characterized by the combustion process, total mass loss (TML) and total heat release (THR). The TML and THR increase with...

The data presented in this article are related to research article "Investigation on thermal and fire propagation behaviors of multiple lithium-ion batteries within the package" (Chen et al., 2019). This data article provides the data information including the experiment pictures, flame temperatures, pressure and heat flux sensors temperatures, and...

As one of the most promising new energy sources, the lithium-ion battery (LIB) and its associated safety concerns have attracted great research interest. Herein, a comprehensive review on the thermal hazards of LIBs and the corresponding countermeasures is provided. In general, the thermal hazards of the LIB can be caused or aggravated by several f...

In this article, the combustion characteristics of different carbonate mixed solvents are considered by means of cone calorimeter. The coexistence system is composed of ternary carbonate mixed solvent and 1-g 2325 separator. Then, the comparison between coexistence systems and corresponding solvent mixtures is conducted. Experimental findings revea...

To investigate the impacts of ambient pressure on thermal runaway and fire behaviors of lithium‐ion battery (LIB), experimental measurement and theoretical analysis with serial conditions are conducted at two altitudes. The well‐designed experimental equipment and operating conditions have enabled the accurate evaluation of ambient pressure effects...

A set of experiments were carried out at reduced and elevated temperatures (−10, −5, 0, 20, 50, 60 and 70 °C)to investigate the homogeneity of lithium-ion batteries under abusive temperature environment in combination with different cycle rates (1C, 2C, 3C and 4C). Based on the experimental results, we found that the surface temperature of battery...

A series of thermal failure researches were conducted to explore the effects of parameters on the failure propagation behavior within battery modules, including the gap between batteries, the state of charge (SOC)and traditional phase change material (PCM). Based on the results, obvious domino phenomena were revealed during the process of thermal f...

Understanding the fire hazard of lithium-ion battery (LIB)is important for the safety issues during their manufacture, storage, transportation, and usage. In this work, experiments are conducted to analyze the mechanisms of thermal and fire propagation of multiple LIBs in the package. According to the results, it is found that the thermal and fire...

In the current work, a series of experiments were carried out under low and normal temperature conditions (0 and 20 °C) to research the influence of low temperature on the performance of lithium-ion batteries (LIBs). Besides this, a commercial insulation material (IM) was employed to research its effect on preventing damage in a battery exposed to...

As known, it is common for lithium ion battery (LIB) to be used under extreme circumstances, among the high temperature circumstance is included. Herein, a series of experiments were conducted at elevated temperatures of 50, 60, and 70°C to examine the performance of LIB. Besides, the application of phase change material (PCM) under such condition...

To better understand the fire risk of primary lithium batteries, the combustion properties of different numbers of primary lithium batteries were investigated experimentally in this work. Based on the t2 fire principle and total heat release results from the experiments, a simplified analysis was developed to predict the fire hazard, and especially...

To investigate the effects of different state of charges (SOCs), external heating powers and charging/discharging treatment on the fire behaviors of 18650 batteries pack, three groups of abuse experiments were conducted with the help of a cone-calorimeter. The fire hazards of batteries pack were characterized by measuring the flame photographs, bat...

Numerous accidents including fires and explosions occurring in transportation and storage of batteries enhance the need of studying the fire performances on batteries. In the current work, series bench-scale tests are conducted using a cone calorimeter to explore the fire behavior of lithium-ion battery. The influence of two key factors, namely sta...

Numerous lithium-ion battery fire accidents raise comprehensive safety concerns in modern society. In this paper, an experimental study was conducted to investigate fire behaviors of lithium-ion batteries under the effect of state of charge and heat treatments. The mass loss, heat release rate, and total heat released could be used as important evi...

Previous experiments at high-altitude environments have indicated that the ambient pressure has an effect on the entrainment coefficient, which further affects the axial temperature profile of a fire plume. However, their substantial relationship remains unclear as only a limited number of tests have been conducted. In this work, a reduced pressure...

In order to have a better understanding of the fire behaviors of lithium-ion battery (LIB) and batteries pack under discharge, a series of fire tests were conducted. The fire behaviors of LIB were characterized by parameters including the flame photographs, surface temperature, mass loss, radiative heat flux and hydrogen fluoride (HF) mass flow. Th...

A lithium-ion battery (LIB) may experience overcharge or over-discharge when it is used in a battery pack because of capacity variation of different batteries in the pack and the difficulty of maintaining identical state of charge (SOC) of every single battery. A series of experiments were established to investigate the thermal and fire characteris...

Thermal failure propagation is one of the most severe challenges for battery modules and it usually aggravates the thermal hazards, further resulting in serious accidents. This work conducted two groups of experiments to investigate the influence of discharging treatment and module shape on the thermal failure propagation of battery modules, where...

To better understand the fire risk of nitrocellulose (NC) used for the civil industry, the combustion properties of NC-alcohol humectant (isopropanol and ethanol) and -plasticizer (dibutyl phthalate) mixtures were investigated experimentally in this work. Flames with considerable sparks were observed for nitrocellulose-humectant samples, while the...

In this paper the difference of fundamental diagrams in pedestrian flow is investigated. A new measurement method in which the moving back is considered as negative contribution to pedestrian flow is proposed based on previous study. Firstly the comparison of different measurement methods is made and small discrepancy in the fundamental diagrams of...

The thermal failure propagation is one of the most severe challenges for battery pack and it usually aggravates the thermal hazards, further resulting in serious accidents. A series of thermal failure researches were conducted to explore the effects of state of charge (SOC), the number of heaters, failure location and pack size on the thermal failu...

To have a better understanding of the thermal behaviors of lithium-ion batteries (LIBs) under discharge and overcharge conditions, some tests were conducted by a cone calorimeter. Several parameters were measured such as the battery surface temperature, voltage, the time to thermal runaway, the time to maximum temperature, heat release rate and tot...

Numerous lithium-ion battery (LIB) fires and explosions have raised serious concerns about the safety issued associated with LIBs; some of these incidents were mainly caused by overcharging of LIBs. Therefore, to have a better understanding of the fire hazards caused by LIB overcharging, two widely used commercial LIBs, nickel manganese cobalt oxid...

With the aid of same configured calorimeters as dimensions of 40% of that in ISO 9705 in Hefei (24 m, 100.8 kPa) and Lhasa (3650 m, 64 kPa), the influence of high altitude on heat release rate and combustion efficiency were investigated. Two groups of liquid pool fires of moderate sizes (D = 0.15, 0.25 m) with fuel level maintaining system were tes...

A series of shredded paper fire experiments were conducted by means of a calorimeter. The mass loss rate and heat release rate were measured. The flame spread process was recorded, which shows that the flame spread process can be divided into four typical stages, and the mean spread rates along different directions were obtained from the observed c...

Although the thermal behaviors including thermal instability of nitrocellulose (NC) and its mixtures with some humectants have been comprehensively examined previously in the literature, their combustion characteristics have not been systematically studied. To address the issue, the combustion properties of NC with alcohol humectants are investigat...

In this paper, a report is given on an experimental study of the combustion characteristics of six bundle lithium-ion batteries in a calorimeter. Several parameters including mass loss, heat release rate, surface temperature and heat flux distribution were measured to evaluate the hazards. The experimental results show that the lithium-ion batterie...

Safety problem is always a significant consideration before wider field of application such as mobile phones, computers and new energy vehicles. However, the knowledge on the battery combustion behavior is limited. To increase the safety margin, the fire hazard of lithium-ion batteries should be considered. An experimental study of different arrang...

To examine the effect of varying ceiling height on the combustion behaviors of pool fires whose flame impinged the ceiling, a series of n-heptane pool fires was performed beneath a ceiling in the range of H ef/D = 0.43–2.5 using a scaled-down calorimeter. Typical parameters including the burning intensity, combustion yields and combustion efficienc...

To increase the safety margin, the fire hazard of lithium battery should be considered. In this research, the experimental results of lithium battery fires were provided, expecting to offer guidance to facilitate the safe handling of battery packs and cells under normal and high-altitude conditions. Single and bundles of primary lithium battery exp...

To validate the feasibility of classical fire scaling laws under low pressure, three typical liquid fuels with different sooting levels, i.e. ethanol, n-heptane and jet-A, were employed in this paper to perform a sequence of pool fires in a high-altitude city, Lhasa (3650 m, 64.3 kPa). Mass loss, axial temperature profile and radiative heat flux we...

In applications of lithium ion batteries, it is a requisite to precisely appraise their fire and explosion hazards. In the current study, a fire calorimeter is utilized to test the combustion performance of two commercial 18650 lithium ion batteries (LiCoO2 and LiFePO4) at different state of charge (SOC). Characteristics on thermal hazards of lithi...

In this article, some of the combustion properties of three carbonate solvent mixtures commonly used as the electrolytes of lithium ion batteries are considered by means of the ISO 5660 cone calorimeter. Experimental findings reveal that the heat release rate, the most important parameter in fire science, exhibits a significant variation among the...

The use of lithium batteries requires understanding their fire and explosion hazards. In this paper, a report is given on an experimental study of the combustion characteristics of primary lithium batteries. Burning tests of single and bundles of primary lithium batteries were conducted in a calorimeter to measure their heat release rates when expo...