Toxic fluoride gas emissions from lithium-ion battery fires - the best 3 burner gas grill

by:Longzhao BBQ     2020-05-06
Toxic fluoride gas emissions from lithium-ion battery fires  -  the best 3 burner gas grill
Lithium-A fire with an ion battery can produce intense heat and a lot of gas and smoke.While emissions of toxic gases may be greater than heat, there is limited knowledge of such emissions.This paper introduces the quantitative measurement of heat release and fluoride gas emissions during fire of seven different types of commercial lithium batteriesion batteries.The results were verified using two independent measurement techniques and indicated that a large amount of fluoride (HF) could be produced with a nominal battery energy capacity between 20-200 mg/Wh.In addition, another potentially toxic gas-15-22 mg/Wh of phosphorus-based fluoride (POF3) was measured in some fire tests.Gas emissions when using fine mist as fire extinguishing agent were also studied.Fluoride gas emissions pose a serious toxic threat, resulting in important findings for risk assessment and management, especially for large Li-Ion battery pack.Lithium-Ion batteries are a technical and commercial success that makes it possible for many applications from mobile phones to electric cars and large power storage devices.However, the occasional occurrence of battery fires has caused some attention, especially the risk of natural fires and the high temperatures generated by such fires.While the fire itself and the heat it generates can be a serious threat in many cases, the risks associated with faulty lithium gas and smoke emissions-In some cases, ion batteries can be a greater threat, especially in restricted environments where people exist, such as in airplanes, submarines, mines, A spacecraft or home equipped with a battery energy storage system.However, gas emissions have only been studied in a very limited range.Irreversible thermal events in lithiumThe ion battery can be started in many ways, spontaneous internal or external short circuitCircuit, overcharging, external heating or fire, mechanical abuse, etc.This can cause an external thermal reaction in the battery to cause the heat to get out of control and eventually cause a fire and/or explosion.Such an event in a big Li-The ion battery pack may be serious due to the risk of failure propagation.Electrolyte in lithium-The ion battery is flammable and usually contains lithium hexorfluoride (LiPF) or other lithiumSalt containing fluorine.If overheated, the electrolyte will evaporate and eventually drain from the battery.The gas may be ignited immediately or not immediately.If the emitted gas is not immediately ignited, the risk of a later gas explosion may be imminent.Li-Various toxic substances and toxic substances are released by ion batteries.g.CO (a choking gas) and CO (causing hypoxia) during heating and combustion ).At high temperatures, the fluorine content of the electrolyte, and to some extent, other parts of the battery, such as the poly-diammonium adhesive in the electrode, can form hydrogen fluorine HF, five fluorine phosphorus (PF) and gas such as phosphorus fluorine (POF.Compounds containing fluorine can also be present in the form of e.g.Flame retardant substances in electrolyte and/or separator, additives and electrode materials, E.G.g.Fluoride phosphate, increase the additional source of fluorine.The presence of water/humidity promotes the decomposition of LiPF according to the following reactions;The life of these PF is quite short.The toxicity of HF and derived HF is well known, while the POF has no toxicity data, it is an active intermediate that can react with other organic materials or with water that ultimately generates HF.According to the chlorine analogy of POCl/HCl, POF may even be more toxic than HF.The decomposition of fluorine compounds is complex, and many other toxic fluorine gases may also be emitted in this case, however, this study focuses on the analysis of HF and POF.Although some qualitative and halfIn order to measure HF from Li-medium, a quantitative attempt has been madeIon batteries under abuse conditions, most studies did not report time-dependent rates or total HF and other fluorine gases in different battery types, battery chemistry and stateof-charge (SOC).In some of the measurements reported, in a limited SOC-Change, abuse Lee-Ion batteries, as well as batteries detected during abuse of battery packs.However, time-Resolution quantitative HF gas emission measurement of complete Li-Until now, only limited studies have been conducted on ion battery batteries experiencing abuse;for a few SOC-Values, including larger business units, smaller-The size of commercial cells and study cells (1)e.non-Commercial community ).Time-Resolution quantitative HF measurement for gas release of complete electric vehicles including Li-Ion battery packs were also carried out during an external fire.Other types of gas emissionsIon cells during abuse have been the subject of more investigations.Since the electrolyte is usually the main source of fluorine, the measurement of fluorine emission from battery-type electrolyte has been studied.For example, a fire or external heating abuse test was performed on the electrolyte and in some cases the quantitative quantities of HF and POF were measured.Other studies of electrolyte exposed to medium temperatures of 50-85 °c have shown that the production of various fluorine compounds, some of which include electrolyte and electrode materials.Our quantitative study of Li-emitting gasesVarious battery types are covered by ion battery fires.We found commercial lithium.Ion batteries emit a lot of HF during the fire, and the emission rate varies for different types of batteries and SOC levels.On the other hand, the POF is only found in one of the battery types and only under 0% SOC.The use of fine mist as fire extinguishing agent may promote the formation of unwanted gases in eqs ()-() our limited measurements indicate that in the application of fine mist, the production rate of HF has increased, however, there is no significant difference in the total amount of HF formed when using or not using fine fog.The experiment is carried out using an external propane burner with the aim of heating and igniting the battery, as described in the method section.Type A 7 different types of batteriesAccording to the provisions of the table, the survey was conducted from seven manufacturers with different capacities, types of packaging, design and cellular chemistry.Type A has lithium cobalt oxide (LCO) cathode and carbon anode, and type B to type E has Lithium-The F-type phosphate (LFP) cathode and carbon anode have nickel-cobalt alumina (NCA) and lithium-aluminum-titanium phosphate (LATP) electrodes when the G-type is a laptop battery pack with an unspecified chemical composition of the battery.All electrolyte contains LiPF.Most batteries tested different SOC levels, from 100% SOC for full charge to 0% SOC for full discharge.The study includedCar size-Classified cells, me.e.High quality industry, long life and other series of production units.Heat release rate (HRR) and emission HF of B-Figure 1 shows the type units with different SOC values.Only 100% SOC batteries show several different peaks, corresponding to a strong flash when the gas emitted and emitted by the battery Burns, for all other cells, over time, the release of heat will be more smooth.These behaviors can also be replicated for other tested cell types, E.G.g.Only 100% SOC batteries show a more violent heat release peak with a strong flash.Measurements of gas emissions during fire testing indicate that the generation of HF is associated with an increase in the HRR, albeit with a delay.From Fig.Obviously, the higher the SOC value, the higher the value of the peak HF release rate.The total HF of different battery types varies greatly, as shown in Fig..HF output in mg/Wh, where Wh is the nominal battery energy capacity, is about 10 times higher for cells with the highest value compared to cells with the lowest value.The different relative quantities of electrolyte and filler materials in the battery may be a simple explanation for this change, but it is difficult for commercial batteries to obtain information about these quantities.For bag cells, the highest HF value was found, and the possible explanation is that hard prism cells and cylindrical cells can produce higher pressure before bursting, quickly release a large amount of gas/steam from the electrolyte.Due to the fast release speed and short reaction time, the combustion reaction may be incomplete and less reaction products will be produced.In tests involving the type G, the cylindrical battery is horizontally layered and therefore has different ventilation directions and may increase Wall loss, which is combined with a very energetic response, it may be suggested why HF is detected only from the filter analysis and not by infrared spectrumanalysis.The tested B-and C-bag cells burn longer and have less intensity.However, the F-bag cell burns faster, probably because it has different electrode materials.The effect of SOC on HF release is less significant, trends in figure 1The HF value of 0% is higher than the SOC of 100%, but there is a significant peak in the SOC of 50%.Although these results are reproducible, it is difficult to explain.In other studies, the test range was significantly narrow and the range involved was smallUsing different abuse methods, the total amount of HF measured with real-real was foundThe time IR of reducing SOC is higher (tests performed at 100%, 50% and 0% SOC ).The HRR curve is used to calculate the total heat release (THR) corresponding to the energy released by the combustion cell ).THR was obtained by integrating the measured HRR (minus burner contribution) throughout the test time.Fig.Displays the energy ratio, that is, the energy generated by the combustion battery, compared to the nominal power capacity that the fully charged battery can provide to the external circuit.Therefore, the energy ratio is a comparison between the chemical energy of Li-and the electric energyIon battery.The energy ratio varies greatly for different battery types, but for each battery the energy ratio is approximately constant and has nothing to do with the SOC level.There are some similarities in the picture.For bag cells, type B and Type C, the highest values are given in both cases, despite the reverse order.This may indicate a large number of combustible materials.g.Compared to other batteries, the electrolyte in these batteries.It is also interesting that the energy ratio varies greatly between the tested cells, ranging from 5 to 21.This is an important knowledge of fire fighting and fire fighting.Therefore, the energy ratio is a fully charged battery called by the indicator, while in normal use, only part of the SOC-For example, half of SOC-is used (50%)Window (corresponding to circulating battery between e.g.30% and 80% SOC ).Conversely, if the total heat release in a particular application is considered divided by the battery capacity used, a higher energy ratio is obtained.A summary of the results is shown in the table.Measuring the thermal release of an overheated battery may include several aspects, E.G.g.The temperature of the battery rises and the gas is burned.Due to changes in battery type, trigger method and other factorsg.If the test is conducted as an external fire test, an external heating or overcharge test, and a test method, E.G.g.Oxygen entering the environment (inert, insufficientGood ventilation or ventilationVentilation fire) and the presence of external igniters will greatly affect the thermal release of the measurements.For example, in a restricted environment, the energy release from an internal cell event may be lower than that from the same cell at the time of an external fire.So use other methods and other types of Li-Ion cells can be significantly different.For all test battert types and selected SOC-Horizontal, the POF of A-type battery can only be quantitatively measured at 0% SOC.Repeated measurements confirmed that only Type A and 0% SOC had POF.Therefore, POF cannot be detected in any other test.The POF is an intermediate compound in which local combustion conditions affect the production of the POF during each test.This shows the importance of investigating many different scenarios.Evaluate the ups when the gas is discharged.In Fig.The HRR of A-type batteries under 0% SOC, the average surface temperature of five batteries and the HF and POF productivity are shown.The POF curve is less noisy than the HF curve due to different signalsto-Noise ratio of infrared instruments of different wavelengths.About 5 minutes after the main heat event, there is a secondary peak in the HRR that does not correspond to any peak in the HF or POF mass flow.The explanation for this may be that the second peak of the heat release rate involves a major non-combustionFluorine-containing compounds.The temperature curve shows a rapid rise above the melting temperature of the aluminum oxide battery housing at a temperature of about 660 °c.At these temperatures, alumina melts and a puddle is formed on the burner bed below the battery.As a result, the thermal conditions inside and around the thermocouple and the rest of the battery have changed a lot, resulting in an obvious increase in temperature.In addition to the time-resolved measurement with the infrared spectrum, the gas-During the test, the washing bottle was used to determine the total fluorine content in the gas emissions.The comparison between the different measurement methods used can be seen in the figure.For cell type.Please note that infrared measurements of HF and POF are performed only and other fluoride compounds are not included.Interestingly, for 0% SOC, the total amount of fluoride measured by gasThe bottle washing technique is matched with infrared spectroscopy and primary filtration analysis.For other SOC values, fluorine content is higher than gasBottle size.Nevertheless, the overall trend observed in infrared measurements with different SOC values has more or less obtained gas-Bottle size.Gas-Some tests involving type B and Type C batteries also use washing bottles.These batteries release higher amounts of HF compared to type.Ratio between infrared plus filter analysis and total value of flouride released in gasThe wash bottles of type B and Type C are between 0.89 and 1.02, indicating a better correlation between IR and gasThe washing machine measures when the HF gas emissions are large.The total amount of A-type POF measured by infrared spectrum at 0% SOC is 2.8u2009g (for 5-cells) and 3.9 u2009 g (10 cells ).Therefore, the total POF output of the specification is 15-22 mg/watt-hour of the nominal battery energy capacity.Anderson, there is very little research on the abuse of POF.HF and POF found when burning propane and Li-mixtureHF: POF production ratio of Ion battery electrolyte between 8:1 and 53: 1.In addition to the HF and POF measurements, there are several different non-Specified peaks were found in infrared spectrum measurementsg.1027 cm and 1034 cm were also seen in other studies.They are typical C-O tensile energy of low molecular weight alcohol in the gas phase, but also-Plane stretching of aromatic compounds.This demonstrates the complexity and limited knowledge of the field.In order to study the effect of water on gas emissions, fire tests were also carried out to apply fine fog during the fire.The reason for this experiment is that water is the preferred fire extinguishing agent for lithium.Ion battery fireHowever, the purpose of this study was not to put out the fire completely.A potential problem with the use of fine fog is that the aqua water may, in principle, increase the formation speed of HF, as seen in Eqs () and ().The figure shows the results of B-type cells with or without exposure to fine fog, please note that the production of HRR and HF is delayed when fine fog is used.In this limited study, the peak rate of HF production increased by 35% when water was used, but there was no significant change in total HF release.A previous study reported similar results.As shown in the figure, fine fog is applied in two different times, A total of 851g of water was added to the reaction area, however, several other large water sources were also present in the experiment, I .E.e.Water produced by Propane combustion and air humidity.Fine fog is cooling the fire, and the top surface of the bag cells is partially covered with liquid water for a period of time;As shown in the figure, this is the reason for the battery fire delay.Fine fog can actually also clean the air by collecting smoke particles, HF can be combined with water droplets, which may reduce the amount of HF in the smoke tube and increase the non-Very toxic hf measured on the surface of the test area (E.G.g.Wall, floor, smoke pipe wall ).
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