This study is supported by the UL Research Institutes. All battery cells in this work were conditioned and prepared in Prof. Chris Yuan&#39;s lab at Case Western Reserve University (CWRU). The test chamber is on loan to CWRU from NASA Glenn Research Center. We received tremendous support on the FTIR gas analyzer from a former PhD student, Dr. Yumi Matsuyama at CWRU, and technical support on the H2 sensor from Jeff Tucker, Brandon Wicks, and Brian Engle from Amphenol Advanced Sensors. We sincerely appreciate the support from Pushkal Kannan and Boyu Wang at CWRU. We would also like to acknowledge the technical discussions with Alexandra Schraiber from UL Solutions.

1. Startup of the FTIR gas analyzer
NOTE: The procedures can be different for different brands and models of the FTIR gas analyzer. The following procedure is for the specific gas analyzer used in this work.
<ol>
	<li>Install a new filter or a clean filter (i.e., one that has been cleaned in an ultrasonic bath) in the filter/valve unit (see Figure 1 and Figure 2).</li>
	<li>Open the valve of the nitrogen cylinder co...

<ol>
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P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+analysis+of+thermal+runaway+and+propagation+in+lithium-ion+battery+modules.">Experimental analysis of thermal runaway and propagation in lithium-ion battery modules.</a> Journal of The Electrochemical Society. 162 (9), 1905 (2015).</li><li>Ghiji, M., Edmonds, S., Moinuddin, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+experimental+and+numerical+studies+of+lithium+ion+battery+fires.">A review of experimental and numerical studies of lithium ion battery fires.</a> Applied Sciences. 11 (3), 1247 (2021).</li><li>Jhu, C. Y., Wang, Y. W., Shu, C. M., Chang, J. C., Wu, H. 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W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal-runaway+experiments+on+consumer+Li-ion+batteries+with+metal-oxide+and+olivin-type+cathodes.">Thermal-runaway experiments on consumer Li-ion batteries with metal-oxide and olivin-type cathodes.</a> RSC Advances. 4 (7), 3633-3642 (2013).</li><li>Joshi, T., Azam, S., Lopez, C., Kinyon, S., Jeevarajan, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Safety+of+lithium-ion+cells+and+batteries+at+different+states-of-charge.">Safety of lithium-ion cells and batteries at different states-of-charge.</a> Journal of The Electrochemical Society. 167 (14), 140547 (2020).</li><li>Ribi&#232;re, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+on+the+fire-induced+hazards+of+Li-ion+battery+cells+by+fire+calorimetry.">Investigation on the fire-induced hazards of Li-ion battery cells by fire calorimetry.</a> Energy &amp; Environmental Science. 5 (1), 5271-5280 (2012).</li><li>Chen, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+on+the+thermal+hazards+of+18650+lithium+ion+batteries+by+fire+calorimeter.">Investigation on the thermal hazards of 18650 lithium ion batteries by fire calorimeter.</a> Journal of Thermal Analysis and Calorimetry. 122 (2), 755-763 (2015).</li><li>Fu, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+experimental+study+on+burning+behaviors+of+18650+lithium+ion+batteries+using+a+cone+calorimeter.">An experimental study on burning behaviors of 18650 lithium ion batteries using a cone calorimeter.</a> Journal of Power Sources. 273, 216-222 (2015).</li><li>Ouyang, D., He, Y., Chen, M., Liu, J., Wang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+study+on+the+thermal+behaviors+of+lithium-ion+batteries+under+discharge+and+overcharge+conditions.">Experimental study on the thermal behaviors of lithium-ion batteries under discharge and overcharge conditions.</a> Journal of Thermal Analysis and Calorimetry. 132 (1), 65-75 (2018).</li><li>Said, A. O., Lee, C., Liu, X., Wu, Z., Stoliarov, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+measurement+of+multiple+thermal+hazards+associated+with+a+failure+of+prismatic+lithium+ion+battery.">Simultaneous measurement of multiple thermal hazards associated with a failure of prismatic lithium ion battery.</a> Proceedings of the Combustion Institute. 37 (3), 4173-4180 (2019).</li><li>Quintiere, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+methods+to+measure+the+energetics+of+a+lithium+ion+battery+in+thermal+runaway.">On methods to measure the energetics of a lithium ion battery in thermal runaway.</a> Fire Safety Journal. 111, 102911 (2020).</li><li>Chen, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+lithium-ion+battery+safety+concerns:+The+issues,+strategies,+and+testing+standards.">A review of lithium-ion battery safety concerns: The issues, strategies, and testing standards.</a> Journal of Energy Chemistry. 59, 83-99 (2021).</li><li>Kennedy, R. W., Marr, K. C., Ezekoye, O. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gas+release+rates+and+properties+from+Lithium+Cobalt+Oxide+lithium+ion+battery+arrays.">Gas release rates and properties from Lithium Cobalt Oxide lithium ion battery arrays.</a> Journal of Power Sourcres. 487, 229388 (2021).</li><li>Essl, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comprehensive+hazard+analysis+of+failing+automotive+Lithium-ion+batteries+in+overtemperature+experiments.">Comprehensive hazard analysis of failing automotive Lithium-ion batteries in overtemperature experiments.</a> Batteries. 6 (2), 30 (2020).</li><li>. Fire characterization and gas analysis of lithium-ion batteries during thermal runaway Available from: <a target="_blank" href="https://ttu-ir.tdl.org/handle/2346/89734">https://ttu-ir.tdl.org/handle/2346/89734</a> (2022)</li><li>FTIR Toxity Test. Fire Testing Technology Available from: <a target="_blank" href="https://www.fire-testing.com/ftir-toxicity-test/">https://www.fire-testing.com/ftir-toxicity-test/</a> (2022)</li></ol>

The authors have no conflicts of interest to disclose.

The most critical steps in the protocol are those concerning the toxic gases released in the LIB thermal runaway. The leak test in step 3.11 needs to be carefully performed to ensure that the toxic gases are confined in the chamber during the experiments. The chamber gas clean-up procedures (steps 7.1-7.14) must also be properly done to mitigate the hazard from the toxic gases. Toxic gases may constitute only a small fraction of the vent gas during LIB thermal runaway. However, even very low concentrations of some toxic ...

In the last few decades, lithium-ion batteries (LIBs) have gained popularity and benefited from tremendous technological advancements. Owing to various advantages (e.g., high energy density, low maintenance, low self-discharge and charge times, and long lifespan), the LIB has been considered a promising energy storage technology and extensively used in various applications, such as large energy storage systems (ESSs), electric vehicles (EVs), and portable electronic devices. While the global demand for LIB cells is expected to double from 725 GWh in 2020 to 1,500 GWh in 20301, there has been a substantial increase in fires and explosions related to LIBs in recent years2. These accidents demonstrate the high risks associated with LIBs, raising concerns regarding their large-scale utilization. To mitigate these concerns, it is crucial to gain a thorough understanding of the process of LIB thermal runaway leading to fires.
Previous accidents have revealed that LIB cells fail when the cell electrochemistry is disrupted by overheating in abnormal operating circumstances (such as external short circuit, rapid discharge, overcharging, and physical damage) or due to manufacturing defects and poor design2,3,4. These events lead to the decomposition of the solid-electrolyte interface (SEI), stimulating highly exothermic chemical reactions between electrode materials and electrolytes. When the heat produced in these reactions exceeds that being dissipated, it results in rapid self-heating of the cells, also known as thermal runaway. Internal temperature and pressure can continue rising until built-up pressure causes the battery to rupture and release flammable, toxic gases at high speed. In a multi-cell battery configuration, a thermal runaway in a single cell, if not controlled, can lead to thermal runaway propagation to other cells and incidents of fire and explosion at catastrophic levels, especially in enclosed spaces with limited ventilation. This poses significant threats to human safety and structures.
In the past few decades, a number of studies have been carried out to investigate the thermal runaway reactions of LIBs leading to the combustion of organic electrolytes inside the battery and the release of flammable gases under different heating conditions2,5,6,7,8,9,10,11,12. For example, Jhu et al.10 demonstrated the hazardous nature of charged cylindrical LIBs compared to uncharged ones using an adiabatic calorimeter. Many other studies focused on the thermal runaway behavior of LIBs at different state-of-charges (SOCs). For example, Joshi et al.13 investigated the thermal runaway of various types of commercial LIBs (cylindrical and pouch) at different SOCs. It was noticed that cells at higher SOCs had a higher chance of undergoing thermal runaway compared to those at lower SOCs. In addition, the minimum SOC for a thermal runaway to occur varied with the cell formats and chemistries. Roth et al.11 tested cylindrical LIBs in an accelerating rate calorimeter (ARC) and observed that, as the SOC increased, the onset temperature of thermal runaway decreased and the acceleration rate increased. Golubkov et al.12 developed a custom-designed test stand and showed that the maximum surface temperature of cylindrical LIBs could be as high as 850 &#176;C. Ribi&#232;re et al.14 used a fire propagation apparatus to investigate the fire-induced hazards of pouch LIBs and noticed that the heat release rate (HRR) and toxic gas production varied significantly with the cell SOC. Chen et al.15 studied the fire behaviors of two different 18650 LIBs (LiCoO2 and LiFePO4) at different SOCs, using a custom-made in situ calorimeter. HRR, mass loss, and maximum surface temperature were found to increase with SOC. It was also demonstrated that the risk of explosion was higher for a fully charged lithium cobalt oxide (LiCoO2) cathode 18650 cell compared to a lithium iron phosphate (LiFePO2) cathode 18650 cell. Fu et al.16 and Quang et al.17 conducted fire experiments on LIBs (at 0%-100% SOCs) using a cone calorimeter. It was observed that LIBs at a higher SOC resulted in higher fire hazards due to shorter lengths of time to ignition and explosion, higher HRR, higher surface temperature, and higher CO and CO2 emissions.
To summarize, previous studies using different calorimeters18,19&#160;(ARC, adiabatic calorimetry, C80 calorimetry, and modified bomb calorimetry) have provided abundant data on the electrochemical and thermal processes associated with LIB thermal runaway and fires (e.g., HRR, compositions of the vented gases) and their dependencies on the SOC, battery chemistry, and incident heat flux2,3,7,20. However, most of these methods were designed originally for conventional solid combustibles (e.g., cellulose samples, plastic) and provide limited information when applied to LIB fires. While some previous tests measured the HRR and the total energy generated from chemical reactions, the kinetics aspects of post-thermal runaway fires were not fully addressed.
The severity of hazards during thermal runaway is mainly dependent on the nature and composition of the gases released2,5. Therefore, it is important to characterize the released gases, the venting rate, and their dependence on the SOC. Some previous studies measured the vent gas compositions of LIB thermal runaway in an inert environment (e.g., in nitrogen or argon)12,21,22; the fire component during the thermal runaway was excluded. In addition, these measurements were mostly performed post-experiments (instead of in situ). Evolutions of vent gas composition during and post-thermal runaway, especially those involving fires and toxic gases, remained under-explored.
It is known that thermal runaway disrupts the electrochemistry of the battery and impacts the cell voltage and temperature. A comprehensive test to characterize the thermal runaway process of the LIB should, therefore, provide simultaneous measurement of the temperature, mass, voltage, and vented gases (rate and composition). This has not been achieved in a single setup in the previous studies. In this study, a new apparatus and test protocol are developed to collect time-resolved data on the cell information, gas compositions, and fire characteristics during and post-thermal runaway of LIB cells23. The test apparatus is shown in Figure 1A. A large (~600 L) environmental chamber is used to confine the thermal runaway event. The chamber is equipped with a pressure relief valve (with a set gauge pressure at 0.5 psig) to prevent pressure rise in the chamber. A Fourier transform infrared (FTIR) gas analyzer is connected to the chamber for in situ gas sampling throughout the test. It detects 21 gas species (H2O, CO2, CO, NO, NO2, N2O, SO2, HCl, HCN, HBr, HF, NH3, C2H4, C2H6, C3H8, C6H14, CH4, HCHO, C6H6O, C3H4O, and COF2). The FTIR sampling rate is 0.25 Hz. In addition, a standalone hydrogen sensor is installed inside the chamber near the FTIR sampling port to record the H2 concentration. Two pumps (a 1.3 cfm chemical-resistant diaphragm pump and a 0.5 hp vacuum pump) are installed in the chamber exhaust line. After each experiment, a chamber clean-up procedure is followed to filter and pump the chamber gas directly to the building exhaust line.
In each experiment, the cell is set up inside the chamber in a sample holder (Figure 1B). Thermal runaway is triggered by a proportional-integral-derivative (PID)-controlled electric heating tape at a constant heating rate of 10 &#176;C/min. Cell surface temperatures are recorded by thermocouples in three different locations along the length of the cell. The mass loss of the cell is measured by a mass balance. The chamber pressure is monitored by a pressure transducer. The cell voltage and the power input (voltage and current) to the heating tape are also recorded. All sensor readings (thermocouples, mass loss, cell voltage, heating tape current, and voltage) are collected by a custom data acquisition program at a rate of 2 Hz. Lastly, two camcorders (1920 pixel x 1080 pixel resolution) are used to record the entire process of the experiments from two different angles.
The objective of developing this new test method is twofold: 1) to characterize the smoke and fire behaviors associated with LIB thermal runaway and 2) to provide time-resolved experimental data that enables the development of high-validity numerical models for battery fires. The long-term goal is to advance the understanding of how thermal runaway propagates between cells in a battery pack and how a battery fire scales up when going from single cells to multi-cell batteries. Ultimately, this will help improve guidelines and protocols for storing and transporting LIBs safely.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Balance</td>
			<td>A&#38;D</td>
			<td>EJ-6100</td>
			<td></td>
		</tr>
		<tr>
			<td>Carbon filter</td>
			<td>Whatman</td>
			<td>WHA67041500</td>
			<td></td>
		</tr>
		<tr>
			<td>Current transducer</td>
			<td>NK Technologies</td>
			<td>AT1-010-000-FT</td>
			<td></td>
		</tr>
		<tr>
			<td>Front camera</td>
			<td>Sony</td>
			<td>FDR-AX53</td>
			<td></td>
		</tr>
		<tr>
			<td>FTIR gas analyzer</td>
			<td>Fire Testing Technology</td>
			<td>Protea atmosFIR AFS-A-15</td>
			<td></td>
		</tr>
		<tr>
			<td>Heating tape (1.00&#34; x 2.00&#34;)</td>
			<td>Birk Manufacturing, Inc.</td>
			<td>BK3512-19.6-L24-03</td>
			<td></td>
		</tr>
		<tr>
			<td>High-temperature resistant tape</td>
			<td>Kapton</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogen sensor</td>
			<td>Amphenol</td>
			<td>AX220135</td>
			<td></td>
		</tr>
		<tr>
			<td>K-type, thermocouple</td>
			<td>Omega</td>
			<td>KMQSS-020U-12</td>
			<td></td>
		</tr>
		<tr>
			<td>LabVIEW</td>
			<td>National Instruments</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Matlab</td>
			<td>MathWorks</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NI-9213</td>
			<td>National Instruments</td>
			<td>NI-9213</td>
			<td></td>
		</tr>
		<tr>
			<td>NI-9219</td>
			<td>National Instruments</td>
			<td>NI-9219</td>
			<td></td>
		</tr>
		<tr>
			<td>NI-cDAQ-9174</td>
			<td>National Instruments</td>
			<td>NI-cDAQ-9174</td>
			<td></td>
		</tr>
		<tr>
			<td>NI-USB-6009</td>
			<td>National Instruments</td>
			<td>NI-USB-6009</td>
			<td></td>
		</tr>
		<tr>
			<td>PID controller</td>
			<td>Omega</td>
			<td>CN8200</td>
			<td></td>
		</tr>
		<tr>
			<td>PILOT5000 Chemical Resistant Diaphragm Vacuum Pump</td>
			<td>The Lab Depot</td>
			<td>TLD5000</td>
			<td></td>
		</tr>
		<tr>
			<td>Pressure relief valve</td>
			<td>Straval</td>
			<td>RVL20-10T-N4675</td>
			<td></td>
		</tr>
		<tr>
			<td>Pressure Transmitter</td>
			<td>Keller</td>
			<td>0308.01601.081303.02</td>
			<td></td>
		</tr>
		<tr>
			<td>Pure Nickel Strip (0.1x5x100mm 99.6% Nickel)</td>
			<td>U.S. Solid Product</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Respirator</td>
			<td>McMaster</td>
			<td>55865T52</td>
			<td></td>
		</tr>
		<tr>
			<td>Respirator Cartridge</td>
			<td>Honeywell&#160;</td>
			<td>75Scp100L</td>
			<td></td>
		</tr>
		<tr>
			<td>Rotary vane vacuum pump (0.5 hp)</td>
			<td>Alcatel</td>
			<td>Pascal 2010</td>
			<td></td>
		</tr>
		<tr>
			<td>Side camera</td>
			<td>Sony</td>
			<td>HDR-CX110</td>
			<td></td>
		</tr>
		<tr>
			<td>Spot Welder</td>
			<td>SUNKKO</td>
			<td>737G+</td>
			<td></td>
		</tr>
		<tr>
			<td>TeamViewer</td>
			<td>TeamViewer</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Voltage transducer</td>
			<td>CR Magnetics Inc.</td>
			<td>CR4510-50</td>
			<td></td>
		</tr>
	</tbody>
</table>

in situ gas analysis and fire characterization of lithium-ion cells during thermal runaway using an environmental chamber

An experimental apparatus and a standard operating procedure (SOP) are developed to collect time-resolved data on the gas compositions and fire characteristics during and post-thermal runaway of lithium-ion battery (LIB) cells. A 18650 cylindrical cell is conditioned to a desired state-of-charge (SOC; 30%, 50%, 75%, and 100%) before each experiment. The conditioned cell is forced into a thermal runaway by an electrical heating tape at a constant heating rate (10 &#176;C/min) in an environmental chamber (volume: ~600 L). The chamber is connected to a Fourier transform infrared (FTIR) gas analyzer for real-time concentration measurements. Two camcorders are used to record major events, such as cell venting, thermal runaway, and the subsequent burning process. The conditions of the cell, such as surface temperature, mass loss, and voltage, are also recorded. With the data obtained, cell pseudo-properties, venting gas compositions, and venting mass rate can be deduced as functions of cell temperature and cell SOC. While the test procedure is developed for a single cylindrical cell, it can be readily extended to test different cell formats and study fire propagation between multiple cells. The collected experimental data can also be used for the development of numerical models for LIB fires.

Videos representing typical thermal runaway processes with and without fires are included in Supplementary File 1 and Supplementary File 2, respectively. Key events are depicted in Figure 5. As the cell temperature is raised (to ~110-130 &#176;C), the cell starts swelling, indicating the buildup of the internal pressure (caused by the vaporization of electrolytes and the thermal expansion of gases inside the cell2). This is followed b...

Watch this Scientific Journal Video about In Situ Gas Analysis and Fire Characterization of Lithium-Ion Cells During Thermal Runaway Using an Environmental Chamber at JoVE.com

In Situ Gas Analysis and Fire Characterization of Lithium-Ion Cells During Thermal Runaway Using an Environmental Chamber

Here, we describe a test procedure developed to characterize thermal runaway and fires in lithium-ion cells through in situ measurements of various parameters in an environmental chamber.

In Situ Gas Analysis and Fire Characterization of Lithium-Ion Cells During Thermal Runaway Using an Environmental Chamber

An experimental apparatus and a standard operating procedure (SOP) are developed to collect time-resolved data on the gas compositions and fire ...

Thermal runaway in lithium-ion batteries occurs due to several causes, which can also result in very different worst case outcomes. In this method, we are trying to simulate a catastrophic hazard in a single cell, and the protocol has been shown to provide consistency in results for the simulation of the type of hazard we want to create. The main advantage of this test procedure is that it measures various parameters in situ in one single test.The time result data comprehensively characterizes the transient event of lithium-ion battery thermal runaway and fires. This experiment requires a synchronization of data acquisition from many sensors, FDIR, and video recording. The operator has to follow the standard operating procedure to operate multiple devices step-by-step correctly.This ensures the success of experiments with consistent results and without potential hazards to personnel and devices. Demonstrating the procedure will be Pushkal Kannan, a PD student, and Dr.Ankit Sharma, a post-doctoral researcher from my lab. To begin, install a new or clean filter in the filter valve unit.Open the valve of the nitrogen cylinder connected to the gas analyzer, and adjust the nitrogen flow rate to 150 to 250 cubic centimeters per minute. With a cell preparation, measure the initial voltage and mass of the cell with a precision of 0.01 grams, and record them on the experiment log sheet. Attach a heating tape to the center of the cell.Ensure that the heating tape wires point toward the negative side of the cell. Take a picture of the cell with the tape. Attach three thermocouples to the cell surface, one near the positive terminal, one in the middle, and one at the bottom near the negative terminal of the cell using high temperature resistant tape.Use the thermocouple near the positive terminal to control the heating rate through the proportional integral derivative, or PID. All three thermocouples should be located five millimeters away from the edge of the heating tape. Take a picture of the cell with a ruler to confirm the distance from the heating tape.Spot weld nickel tabs to the positive and negative terminals of the cell for the cell voltage measurement, then load the cell on the cell holder. Place the cell and the cell holder on the mass balance in the chamber. Connect the thermocouple connectors, heating tape, and nickel tabs to the chamber feed-through plugs and wires.Turn on the PID controller for the heating tape, and set up the heating profile. Connect the cables for the PID controller, data acquisition, and the mass balance to a laptop, and start the data acquisition program on the laptop. Make sure all the sensor readings shown in the data acquisition program are reasonable.After checking the measurements, turn off the data acquisition program. Adjust the front and side view camcorder settings, manual white balance, manual focus, auto exposure, auto iris, and auto shutter speed. Make sure that the camcorder battery is full.Position the front view camcorder on a tripod outside the chamber, start recording on the side view camcorder, and place it inside a protection box in the chamber. After checking the side view camcorder angle and view, lock the protection box. Close the chamber, and ensure all the screws on the cover plates are tightly fastened.Use the vacuum or diaphragm pump to conduct a leak check, and change the FTIR intake from ambient air to the chamber. Then connect the FTIR return line to the chamber. Set the PID controller to ramp soak mode, and turn off the light in the room and the LED light in the chamber.Start the front view camcorder recording, and then record the following startup process to synchronize the data acquisition and video recording. Start the data recording and the data acquisition program on the laptop. Start the PID ramp soak mode at 10 seconds on the data acquisition program timer, turn on the chamber LED light, and start the FTIR recording.Position the front view camcorder on the tripod, and continue recording the experiment. Move to a different room, and continue monitoring the data acquisition panel on the laptop through a remote controlled desktop program. When thermal runaway occurs, or after the PID controller has maintained the cell temperature at 200 degrees Celsius for 60 minutes, turn off the power to the heating tape, and set the PID controller to standby mode.End the experiment and data recording when all three thermocouple readings become lower than 40 degrees Celsius. Purge the FTIR gas analyzer with nitrogen to clean the tube in the analyzer for around 15 minutes. After purging, stop the FTIR measurement.Before the chamber cleanup vacuuming procedure, check if the FTIR sampling intake line is closed or open to the ambient air. Select ambient air on the Protea Analyser Software, or PAS-Pro Software, or shut down the FTIR entirely. Open valve one to prepare for partially vacuuming the chamber using the chemical resistant diaphragm pump, and run the diaphragm pump until the chamber pressure drops to 9.7 pounds per square inch absolute.Turn off the diaphragm pump, and close valve one, then open valve three to fill the chamber with ambient air. Close valve three when the chamber pressure recovers to the ambient pressure. After lowering the concentration of toxic gases by partially vacuuming the chamber with the diaphragm pump, run a rotary vein pump until the chamber pressure drops to 4.7 pounds per square inch absolute to remove the rest of the toxic gases.Open the chamber, and retrieve the camcorder and the cell. Take photos before, during, and after taking the cell off the cell holder. Weigh the cell, and record the post-test mass of the cell.Finally, post-process the collected data, and generate plots to visualize the time evolution of all measurements. The cell temperature and mass loss data obtained for an 18650 cylindrical cell at 75%state of charge is shown in this figure. The mass loss indicates two distinct gas release periods, one during cell venting, and the other during thermal runaway.The concentrations of major hydrocarbon and toxic gas species are shown here. The recorded current and voltage supplied to the heating tape can be used to calculate the power input to the cell. The representative data for voltage and current supplied to the heating tape and calculated energy and power supplied to the heating tape are presented here.The most important factor here is to ensure safety during and post each experiment. The experiment must prevent an external short circuit of the test cell. And the other critical factors are confirming that the cell SoC and the heating rates are verified to be correct before the test.It is also critical to seal the chamber completely to confine the exhaust of toxic gases, and follow the cleanup procedure exactly to remove the gases in a safe manner. The test procedure can be extended to study fire application in different cell formats and modules, advancing our understanding of thermal runaway and battery fire scaling in multi-cell batteries. The comprehensive time result data collected in this test procedure enables the development of future models and theories of lithium-ion batteries.It will also help to understand how battery fire scales up.

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Research

JoVE Journal

Engineering

1.8K vistas.  Case Western Reserve University. La fuga térmica en las baterías de iones de litio ocurre debido a varias causas, que también pueden resultar en resultados muy diferentes en el peor de los casos. En este método, estamos tratando de simular un peligro catastrófico en una sola célula, y se ha demostrado que el protocolo proporciona consistencia en los resultados para la simulación del tipo de peligro que queremos crear. La principal ventaja de este procedimiento de prueba es que mide varios parámetros in situ en una so...