scholarly journals Impact of Lithium Salts on the Combustion Characteristics of Electrolyte under Diverse Pressures

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5373
Author(s):  
Changcheng Liu ◽  
Que Huang ◽  
Kaihui Zheng ◽  
Jiawen Qin ◽  
Dechuang Zhou ◽  
...  

The electrolyte is one of the components that releases the most heat during the thermal runaway (TR) and combustion process of lithium-ion batteries (LIBs). Therefore, the thermal hazard of the electrolyte has a significant impact on the safety of LIBs. In this paper, the combustion characteristics of the electrolyte such as parameters of heat release rate (HRR), mass loss rate (MLR) and total heat release (THR) have been investigated and analyzed. In order to meet the current demand of plateau sections with low-pressure and low-oxygen areas on LIBs, an electrolyte with the most commonly used lithium salts, LiPF6, was chosen as the experimental sample. Due to the superior low-temperature performance, an electrolyte containing LiBF4 was also selected to be compared with the LiPF6 sample. Combustion experiments were conducted for electrolyte pool fire under various altitudes. According to the experimental results, both the average and peak values of MLR in the stable combustion stage of the electrolyte pool fire had positive exponential relations with the atmospheric pressure. At the relatively higher altitude, there was less THR, and the average and peak values of HRR decreased significantly, while the combustion duration increased remarkably when compared with that at the lower altitude. The average HRR of the electrolyte with LiBF4 was obviously lower than that of solution containing LiPF6 under low atmospheric pressure, which was slightly higher for LiBF4 electrolyte at standard atmospheric pressure. Because of the low molecular weight (MW) of LiBF4, the THR of the corresponding electrolyte was larger, so the addition of LiBF4 could not effectively improve the safety of the electrolyte. Moreover, the decrease of pressure tended to increase the production of harmful hydrogen fluoride (HF) gas.

2016 ◽  
Vol 37 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Monika Kosowska-Golachowska ◽  
Agnieszka Kijo-Kleczkowska ◽  
Adam Luckos ◽  
Krzysztof Wolski ◽  
Tomasz Musiał

Abstract The objective of this study was to investigate combustion characteristics of biomass (willow, Salix viminalis) burnt in air and O2/CO2 mixtures in a circulating fluidized bed (CFB). Air and oxy-combustion characteristics of wooden biomass in CFB were supplemented by the thermogravimetric and differential thermal analyses (TGA/DTA). The results of conducted CFB and TGA tests show that the composition of the oxidizing atmosphere strongly influences the combustion process of biomass fuels. Replacing N2 in the combustion environment by CO2 caused slight delay (higher ignition temperature and lower maximum mass loss rate) in the combustion of wooden biomass. The combustion process in O2/CO2 mixtures at 30% and 40% O2 is faster and shorter than that at lower O2 concentrations.


2012 ◽  
Vol 457-458 ◽  
pp. 607-610
Author(s):  
Feng Lu ◽  
Meng Chao Guo ◽  
Guang Jun Guo

A simulation model on working process of certain armored vehicle turbocharged diesel engine is proposed with Hiroyasu combustion model.Then the combustion characteristics of the diesel in 4km altitude is calculated. The combustion process is improved via adjusting optimum advanced injection angle(θi) which performed in plateau area.The results show: when the altitude is from 0m to 4000m, the center of gravity for heat release rate is delayed 7°CA,HRRmax (maximum value of Heat Release Rate) reduces 0.009KJ/°CA, pmax (maximum value of cylinder Pressure ) reduces1.6MPa,Tmax(maximum value of combus -tion temperature ) increases 220°C above. When θi is advanced during possible scope, HRRmax increases 0.008KJ/°CA,pmax increases 1.0MPa,Tmax increase 150°C. In view of the restriction of the pmax and the maximum increase rate of p, the optimum θi is fixed on to advanced 4°CA. The simulation results supply a research foundation for the improvement of diesel performance in Plateau.


2005 ◽  
Vol 14 (3) ◽  
pp. 321 ◽  
Author(s):  
David R. Weise ◽  
Robert H. White ◽  
Frank C. Beall ◽  
Matt Etlinger

The flammability of living vegetation is influenced by a variety of factors, including moisture content, physical structure and chemical composition. The relative flammability of ornamental vegetation is of interest to homeowners seeking to make their homes ‘fire safe’. The relative importance of the factors influencing fire behaviour characteristics, such as flammability, is unknown. In the present study, oxygen consumption calorimetry was used to obtain selected combustion characteristics of ornamental vegetation. Peak heat release rate, mass loss rate, time to ignition and effective heat of combustion of 100 × 100-mm samples of foliage and small branches were measured using a bench-scale cone calorimeter. Green and oven-dry samples of 10 species were collected and tested seasonally for a period of 1 year. Similar measurements were made on whole shrubs in an intermediate-scale calorimeter. The range of cone calorimeter peak heat release rates for green and oven-dry samples was 1–176 and 49–331 kW m−2, respectively. Moisture content significantly reduced heat release rates and increased time to ignition. Peak heat release rates for Olea europea and Adenostoma fasciculatum were consistently highest over the year of testing; Aloe sp. consistently had the lowest heat release rate. The correlation of peak heat release rates measured by the cone calorimeter and an intermediate-scale calorimeter was statistically significant yet low (0.51). The use of the cone calorimeter as a tool to establish the relative flammability rating for landscape vegetation requires additional investigation.


Author(s):  
Hendry Y. Nanlohy

A comparative study on the combustion characteristics of a single droplet fueled by DEX, crude jatropha oil (CJO), and a mixture of CJO with a magnetic liquid catalyst of rhodium trisulfate has been carried out under normal gravity conditions. The high viscosity of crude jatropha oil makes it difficult to burn under normal conditions (room temperature and atmospheric pressure), therefore the addition of a magnetic liquid catalyst rhodium trisulfate is needed to improve the properties of crude jatropha oil. As a catalyst, rhodium trisulfate has the potential to improve combustion performance while improving the physical properties of crude jatropha oil as an alternative fuel for the better. Furthermore, performance tests were also carried out with DEX fuel with a cetane number (CNs) 53. The results showed that compared to DEX, it was seen that the liquid metal catalyst rhodium trisulfate succeeded in making crude jatropha oil more charged so that the combustion process was better. This is evidenced by a significant change in the dimensions of the flame and an increase in the combustion temperature. Moreover, it is also seen that the burning rate increases and the ignition delay become faster.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2511
Author(s):  
Changcheng Liu ◽  
Kaihui Zheng ◽  
Yong Zhou ◽  
Kai Zhu ◽  
Que Huang

Electrolytes are involved in the thermal runaway (TR) process of cells, which is a potential hazard in lithium-ion batteries (LIBs). Therefore, the effects of different mass ratio of carbonate solvents (ethylene carbonate (EC)/propylene carbonate (PC)/ethyl methyl carbonate (EMC)) with LiBF4 and different environmental pressure on the combustion characteristics of electrolyte such as flame centerline temperature, mass loss rate (MLR) and heat release rate (HRR) were analyzed. The combustion process could be divided into four stages: ignition, stable combustion stage, stable combustion with flame color change stage and extinguishing; with the decrease of pressure, the MLR of electrolyte declined and the combustion time prolonged, while the temperature of flame centerline increased.


2020 ◽  
pp. 089270572093593
Author(s):  
Nour Fathi Attia ◽  
M Nour ◽  
M Hassan ◽  
G Mohamed ◽  
H Oh ◽  
...  

Well dispersed polyethylene (PE) nanocomposites were developed. Montmorillonite (MMT) as aluminosilicate clay layers was modified using organic silanes of different side chains. The MMT was grafted using 3-(trimethoxysilyl)propylamine, N-[3-(trimethoxysilyl)propyl]ethylenediamine, and trimethoxyvinylsilane. The modification process of MMT using organic different silanes was elucidated using microscopic, thermogravimetric, spectroscopic, and X-ray diffraction tools. Then, the developed organoclays were dispersed uniformly in PE matrix producing well exfoliated and dispersed polymer nanocomposites. The mass loadings of dispersed organoclay were varied and the impact of organic silane structure was studied. Thermal stability and flammability properties of the developed polymer nanocomposites were evaluated. The peak heat release rate and average heat release rate were reduced by 48% and 61%, respectively compared to virgin polymer. Also, the average mass loss rate was significantly reduced by 50%. This is in addition to reduction in emission of carbon monoxide (CO) and carbon dioxide (CO2) by 45% and 56%, respectively. The effect of side chain of organosilane on the performance of modified clay layers was studied. The toxicity of gases evolved during combustion process of PE and their polymer nanocomposites were evaluated using Fourier transform infrared connected to cone calorimeter. Additionally, the influence of organic silane on the pyrolysis and toxic gases emission was further studied.


2021 ◽  
Vol 35 (3) ◽  
pp. 1-6
Author(s):  
Soo-Gyeong Park ◽  
Sin-Woo Kim ◽  
Eui-Ju Lee

The lithium-ion battery is the most popular type of secondary battery because of its high energy density. It has been widely used in mobile power and energy storage systems. However, several accidents can occur in systems using lithium-ion batteries, and most of the reported losses have resulted from battery fires and explosions. In this study, a cone calorimeter experiment was performed to investigate the fire characteristics of lithium-ion batteries and assess their heat release rate (HRR), which is the most representative property for fire events. Fires involving cylindrical standard batteries consist of two combustion stages. The first burning stage is due to the package material and intercalated lithium of the battery, and the second stage is attributed to the thermal runaway reactions of the electrolyte. The second combustion stage has a greater peak HRR than the first stage and is accompanied by a violent explosion. In a comparison of the HRRs with the oxygen consumption rate, the HRRs measured on the basis of the mass loss rate show higher maximum values and extremely narrow heat release times.


2019 ◽  
Vol 118 ◽  
pp. 01034
Author(s):  
Guoan Zhang ◽  
Lingling Wei ◽  
Junhao Gao ◽  
Tingting Qiu ◽  
Rongnan Yuan ◽  
...  

Polyvinyl chloride foam (PVC) is widely used as the wall materials of the high-speed train. The combustion characteristics of PVC foam under the heat fluxes of 20-60 kW/m2 are investigated by fire Propagation Apparatus (FPA). The results show that the ignition time of PVC foam decreases with the increase of heat flux. The peak of heat release rate, mass loss rate and smoke production rate increase with the increase of heat flux. Under the condition of 60 kW/m2, the heat release rate has the peak value of 109.10 kW/m2. The research on the combustion characteristics of the PVC can be used to analyse the fire risk of the train and guide the formulation of safety measures.


Author(s):  
V. A. Poryazov ◽  
◽  
O. G. Glotov ◽  
V. A. Arkhipov ◽  
G. S. Surodin ◽  
...  

The goal of this research is to obtain experimental information about combustion characteristics of the composite propellant containing various metallic fuels. The propellant formulations contained two fractions of ammonium perchlorate (64.6%), inert binder (19.7%) - butadiene rubber SKD plastized with transformer oil, and metal fuel (15.7% of aluminum ASD-4, ASD-6, Alex; boron; aluminum diboride; aluminum dodecaboride; some mixtures of above listed ingredients). Experimental information will be used further as a background to develop the physical and mathematical model of combustion process.


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