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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Exploring thermal runaway propagation in Li-ion batteries through high-speed X-ray imaging and thermal analysis: Impact of cell chemistry and electrical connections

Battery safety design is important to consider from the individual Li-ion cell to the level of the macro-system. On the macro-level, failure in one single cell can lead to propagation of the thermal runaway and rapidly set a whole battery pack on fire. Factors that can impact the propagation outcome, such as cell model/chemistry and electrical connection are here investigated using a combination of measurements. Several abusive tests were conducted, combining two different cell models (Molicel P42A and LG M50, both 21700s) in series and parallel connections (16 tests per configuration). Overall, a propagation outcome of 56% was measured from the 32 conducted tests, a minimum temperature of 150 °C was required to initiate propagation, and the fastest propagation occurred in 123 s. Temperature measurements were higher in series connected cells, initiating the discussion of cell chemistry and internal resistance on this effect. The difference in current-flow during thermal runaway in series and parallel connections, and how this can affect the temperature evolution is further discussed. Spatio-temporal mapping of X-ray radiography allowed us to derive the speed of thermal runaway evolution inside the battery and has shown that series connected cells, in particular P42A, occur faster. It was further observed that deviant sidewall behaviors such as temperature-induced breaches and pressure-induced ruptures occurred in P42As only respective nail-penetrated cells only.

25 ENERGY STORAGE↗
DOE OSTI2025

Mechanically induced thermal runaway severity analysis of Li-ion batteries and continuous energy release monitoring

The large-scale deployment of Li-ion batteries in stationary energy storage and electrical vehicle applications demands a strong focus on safety, particularly on the thermal runaway risk and severity evaluation. A standardized single-side mechanical indentation test protocol was developed to induce an internal short-circuit (ISC) and evaluate cells' thermal runaway severity at different state of charge (SOC). The observed hazard severity (OHS in five categories) and evaluated scores in this work have a comprehensive consideration of each cell's capacity, initial voltage, SOC, temperature and voltage change, allowing a better evaluation of the cells' thermal runaway potential. This method was applied to about 200 Li-ion batteries in order to build an extensive thermal runaway database covering various SOCs, capacities and chemistries. In this study, we monitored the transitions of stored electrochemical energy and applied mechanical energy into both thermal energy and acoustic emissions (AE). The surface temperature and mechanical failures were monitored by infrared imaging and AE to capture critical events within battery cells throughout the mechanical indentation tests. Furthermore, the initial temperature maps can predict two types of follow-up events: thermal runaway or gradual heat release via conduction. Analyzing each cell's severity, AEs, and leveraging the evolving database offer insights into predicting occurrences of thermal runaway. The test method, thermal runaway severity evaluation and prediction, and the corresponding database provide battery designers, manufacturers, and end-users a clear overview of Li-ion batteries' thermal runaway potential under mechanical abuse, advancing the safety design of Li-ion batteries.

Acoustic emission↗
NASA NTRSDate not supplied

Predicting Maximum Thermal Response in a Li-ion Cell as a Thermal Runaway Predictor for a UAV Fight

As the energy storage devices continue to "pack" more energy in a small space, any damage, battery component failure, manufacturing defect, or electrically abusing the battery can lead to catastrophic thermal runaway events. A catastrophic thermal event in a cell leads to high temperature, in some instances to spewing of battery materials due to gas development from side reactions initiated due to high internal temperatures. Moreover, a thermal runaway can propagate from a single "failed" cell to a whole battery pack, resulting in a more serious event. The commercial and automotive sectors need to mitigate thermal runaway events. An electric aircraft (or air taxi) has no alternative in the event of a failure, so preventing such events is paramount. Currently, battery prognostics algorithms only predict the state-of-charge (SOC) and end-of-life (EOL) of a Li-ion battery in a UAV (unmanned air vehicle), but do not predict the maximum temperature during a flight or the likelihood of thermal runaway. Our current work focuses on adding the thermal model (based on Birkl's OCV model, in Ref. [1]) to the existing hybrid electrochemical model (single-particle model with lumped parameters as in Ref. [2]) to determine end-of-discharge, end-of-life, and maximum temperature during discharge.

Thermal runaway↗
DOE OSTI2021

LIM1TR: Lithium-Ion Modeling with 1-D Thermal Runaway (V.1.0)

LIM1TR (Lithium-Ion Modeling with 1-D Thermal Runaway) is an open-source code that uses the finite volume method to simulate heat transfer and chemical kinetics on a quasi 1-D domain. The target application of this software is to simulate thermal runaway in systems of lithium-ion batteries. The source code for LIM1TR can be found at https://github.com/ajkur/lim1tr. This user guide details the steps required to create and run simulations with LIM1TR starting with setting up the Python environment, generating an input file, and running a simulation. Additional details are provided on the output of LIM1TR as well as extending the code with custom reaction models. This user guide concludes with simple example analyses of common battery thermal runaway scenarios. The corresponding input files and processing scripts can be found in the “Examples” folder in the on-line repository, with select input files included in the appendix of this document.

25 ENERGY STORAGE↗
DOE OSTI2023

Mechanically induced thermal runaway severity analysis for Li-ion batteries

Thermal runaway is one of the most important safety concerns in the deployment of Li-ion batteries. For this study, we developed a standardized single-side indentation test protocol to induce an internal short-circuit. Cell voltage, temperature, and applied compressive force are monitored as a function of time. Each cell is given an observed hazard severity (OHS in five categories) modified from the EUCAR table. Meanwhile a calculated hazard severity (CHS) is obtained solely based on temperature and voltage curves. The calculation formula considers the cell temperature, rate of temperature increase, cell capacity, state of charge (SOC), voltage drop, and voltage drop rate. Each term is assigned with an appropriate weight to scale the calculated score from 0 to100. This method was applied to >100 Li-ion batteries with various SOCs and chemistries, and their OHS and CHS were displayed against SOC. The purpose is to provide battery designers, manufacturers, and end-users a clear comparison of thermal runaway severity of different batteries.

25 ENERGY STORAGE↗
DOE OSTI2021

Prevention of lithium-ion battery thermal runaway using polymer-substrate current collectors

Isolating electronically conducting material from internal short circuits is a promising way to prevent the onset of thermal runaway within lithium-ion cells. Here, a metal-coated polymer current collector, which is designed to disconnect internal short circuits by withdrawing from the heating region, is tested in 18650 cells. In addition to having lower mass and manufacturing costs, cells with metal-coated polymer current collectors demonstrate a reduced risk of thermal runaway during nail penetration. High-speed synchrotron X-ray radiography of 18650 cells during nail-penetration testing, in tandem with pre- and post-mortem X-ray computed tomography, provides insights into the function of the current collectors. The results are compared with those of 18650 cells with standard commercial aluminum and copper current collectors. Cells with aluminum-coated polymer current collectors demonstrated 100% success in thermal runaway prevention during nail penetration, retaining a cell voltage >4.00 V, while standard cells consistently experienced thermal runaway.

25 ENERGY STORAGE↗
DOE OSTI2022

Compressible battery foams to prevent cascading thermal runaway in Li-ion pouch batteries

Lithium-ion battery packs require thermal management to achieve optimum life and safety. This is becoming crucial for battery packs composed of high-energy-density cells. Pouch cells themselves achieve highest packaging efficiency but require additional structural support and thermal management when grouped into modules, especially under abusive conditions such as thermal runaway. Novel foam battery pads have demonstrated to cushion volume changes of pouch cells and are reengineered in this study to mitigate cell-to-cell thermal runaway propagation. The compressible pads are made of polyurethane foams incorporating flame-retardant additives or coatings, including intumescent and fire wall materials. Here their performances were evaluated by conducting nail penetration tests on modules composed of pouch cells at 100% state of charge (SOC), with the foams placed in between the cells. Experimental results show cascading thermal runaway was considerably delayed by polyurethane foams incorporating flame-retardant additives or coatings. Complete prevention of cascading failure was achieved with dense polyurethane foams with multilayered coatings of both fire wall and intumescent materials.

25 ENERGY STORAGE↗
DOE OSTI2024

Counter Data Paucity through Adversarial Invariance Encoding: A Case Study on Modeling Battery Thermal Runaway

Lithium-ion batteries, widely used for their durability and high energy storage, face the risk of internal short circuits leading to catastrophic thermal runaway events. These events, triggered by external stimuli like mechanical loads, pose safety concerns in applications such as electric vehicles. Detecting and understanding thermal runaway events is crucial, but physics-driven models struggle to explain the non-linear evolution of battery temperature during these events, considering factors like material composition and state-of-charge. Due to the rarity of these events and the cost of data collection, we propose a deep learning (DL) model to predict battery temperature responses during thermal runaway. The challenge lies in the scarcity of data, making traditional DL models prone to overfitting and learning low-quality representations of the complex process.Our approach introduces a novel few-shot architecture that incorporates an adversarially governed invariant encoding process. This architecture aims to distill "invariant" relationships by addressing distributional shifts in data across various battery properties, facilitating the detection of thermal runaway events. Specifically, our results demonstrate that deep learning models conditioned on these "invariant" representations outperform state-of-the-art baselines, achieving a remarkable 96.8% performance improvement in terms of the popular metric MAPE. This framework presents a promising direction for enhancing battery safety modeling, particularly in the context of rare and complex events like thermal runaway. Our code and code and dataset used for the paper are public1.

Tabassum, Anika [ORNL] (ORCID:0000000254600955)↗
DOE OSTI2024

The battery failure databank: Insights from an open-access database of thermal runaway behaviors of Li-ion cells and a resource for benchmarking risks

The thermal response of Li-ion cells can greatly vary for identical cell designs tested under identical conditions, the distribution of which is costly to fully characterize experimentally. The open-source Battery Failure Databank presented here contains robust, high-quality data from hundreds of abuse tests spanning numerous commercial cell designs and testing conditions. Data was gathered using a fractional thermal runaway calorimeter and contains the fractional breakdown of heat and mass that was ejected, as well as high-speed synchrotron radiography of the internal dynamic response of cells during thermal runaway. The distribution of thermal output, mass ejection, and internal response of commercial cells are compared for different abuse-test conditions, which when normalized on a per amp-hour basis show a strong positive correlation between heat output from cells, the fraction of mass ejected from the cells, their energy- and power-density. Ejected mass was shown to contain 10x more heat per gram than non-ejected mass. The causes of 'outlier' thermal and ejection responses i.e., extreme cases, are elucidated by high-speed radiography which showed how occurrences such as vent clogging can create more hazardous conditions. High-speed radiography also demonstrated how the time-resolved interplay of thermal runaway propagation and mass ejection influences the total heat generated.

25 ENERGY STORAGE↗
DOE OSTI2022

Avoiding thermal runaway in lithium-ion batteries using ultrasound detection of early failure mechanisms

Thermal runaway leading to catastrophic failure has slowed the adoption of lithium-ion batteries, highlighting the need for early warning systems. In this work, ultrasound is used to detect physical changes in 0.950 Ah Li-ion battery cells by inducing conditions associated with thermal runaway. Ultrasound signal features are extracted as the batteries are cycled under baseline conditions and subsequently subjected to constant current and voltage overcharges. Two conditions identifying failure are defined: a warning to detect the start of overcharge and an emergency stop (E-stop), to immediately take the battery out of service. Using changes in ultrasound signal features, consistent warning and stopping classifications are applied to all failure experiments. On average, a warning notification was issued after 15% of the overcharge time and an E-stop was triggered after 35% of total overcharge duration before failure. Further testing suggests that it is possible to avoid thermal runaway by reacting to intermediate, warning notifications prior to an immediate E-stop. In other words, not only can detection derived by ultrasound identify battery failure before a catastrophic event, but can also provide early, actionable warnings so that overcharges can be detected and corrected quickly enough so the battery does not need to be decommissioned.

25 ENERGY STORAGE↗
DOE OSTI2024

Effects of Trigger Method on Fire Propagation during the Thermal Runaway Process in Li-ion Batteries

Lithium-ion batteries are prone to fire hazards due to the possibility of thermal runaway propagation. During battery product development and subsequent safety tests for design validation and safety certification, the thermal runaway onset is triggered by various test methods such as nail penetration, thermal ramp, or external short circuit. This failure initiation method affects the amount of heat contributions and the composition of gas generations. This study compares two such trigger methods, external heating and using a thermally-activated internal short circuit device (ISCD). The effects of the trigger method on total heat generation are experimentally investigated within 18650 cylindrical cells at single cell level as well as at multiple cell configuration level. The severity of failure was observed to be worse for cells with ISCDs at single cell level, whereas quite the opposite results were observed at multiple cell configuration level. A preliminary numerical analysis was performed to better understand the battery safety performance with respect to thermal runaway trigger methods and heat transfer conditions.

25 ENERGY STORAGE↗
NASA NTRS2014

Can Cell to Cell Thermal Runaway Propagation be Prevented in a Li-ion Battery Module?

Increasing cell spacing decreased adjacent cell damage center dotElectrically connected adjacent cells drained more than physically adjacent cells center dotRadiant barrier prevents propagation when fully installed between BP cells center dotBP cells vent rapidly and expel contents at 100% SOC -Slower vent with flame/smoke at 50% -Thermal runaway event typically occurs at 160 degC center dotLG cells vent but do not expel contents -Thermal runaway event typically occurs at 200 degC center dotSKC LFP modules did not propagate; fuses on negative terminal of cell may provide a benefit in reducing cell to cell damage propagation. New requirement in NASA-Battery Safety Requirements document: JSC 20793 Rev C 5.1.5.1 Requirements - Thermal Runaway Propagation a. For battery designs greater than a 80-Wh energy employing high specific energy cells (greater than 80 watt-hours/kg, for example, lithium-ion chemistries) with catastrophic failure modes, the battery shall be evaluated to ascertain the severity of a worst-case single-cell thermal runaway event and the propensity of the design to demonstrate cell-to-cell propagation in the intended application and environment. NASA has traditionally addressed the threat of thermal runaway incidents in its battery deployments through comprehensive prevention protocols. This prevention-centered approach has included extensive screening for manufacturing defects, as well as robust battery management controls that prevent abuse-induced runaway even in the face of multiple system failures. This focused strategy has made the likelihood of occurrence of such an event highly improbable. b. The evaluation shall include all necessary analysis and test to quantify the severity (consequence) of the event in the intended application and environment as well as to identify design modifications to the battery or the system that could appreciably reduce that severity. In addition to prevention protocols, programs developing battery designs with catastrophic failure modes should take the steps necessary to assess the severity of a possible thermal runaway event. Programs should assess whether there are reasonable design changes that could appreciably affect the severity of the outcome. Evaluation should include environmental effects to surrounding hardware (i.e., temperature, pressure, shock), contamination effects due to any expelled contaminates, and venting propulsive effects when venting overboard.

Jeevarajan, Judith↗
DOE OSTI2021

Investigating the Role of Energy Density in Thermal Runaway of Lithium-Ion Batteries with Accelerating Rate Calorimetry

This work uses accelerating rate calorimetry to evaluate the impact of cell chemistry, state of charge, cell capacity, and ultimately cell energy density on the total energy release and peak heating rates observed during thermal runaway of Li-ion batteries. While the traditional focus has been using calorimetry to compare different chemistries in cells of similar sizes, this work seeks to better understand how applicable small cell data is to understand the thermal runaway behavior of large cells as well as determine if thermal runaway behaviors can be more generally tied to aspects of lithium-ion cells such as total stored energy and specific energy. We have found a strong linear correlation between the total enthalpy of the thermal runaway process and the stored energy of the cell, apparently independent of cell size and state of charge. We have also shown that peak heating rates and peak temperatures reached during thermal runaway events are more closely tied to specific energy, increasing exponentially in the case of peak heating rates.

25 ENERGY STORAGE↗
DOE OSTI2025

A round bobbin critical current measurement and thermal runaway simulation of REBCO coated conductors

A round bobbin test has been widely used to measure critical current Ic of practical superconductors including Nb–Ti, Nb3Sn, and Bi-2212 round strands at 4.2 K and in high magnetic fields but rarely used for rare earth-barium-copper-oxide (REBCO) coated conductor tapes. Here, we applies this method to REBCO tapes and test their Ic at 77 K, self-field, and 4.2 K with a magnetic field of 14 T applied parallel to the tape. The sample carries very high current densities; it is 1.3 m long and has a dense array of voltage taps that allows probing localized thermal runaways and correlation with Ic variations along the length. At 77 K, the Ic values of all sections were measured and found to be rather uniform. However, at 4.2 K, we found that a 3 cm section has 90% of the overall voltage drop and it went into thermal runaways upon further increasing current. Thus, at 4.2 K, we were prevented by localized thermal runaways and unable to determine Ic of most of the REBCO conductor sections; this behavior is different from Bi-2212 and Bi-2223 for which Ic of all turns of a round barrel sample can be determined. We simulate REBCO tapes during current ramping to a thermal runaway and analyze impacts of various factors including cooling, conductor n-values, and thickness of stabilizer on the thermal runaway current Iq. The combined experiments and simulations identify n-value as a crucial factor that leads to the observed differences between Bi-2212 and REBCO. Together with cooling and the standard deviation of Ic variations along the length, the n-value determines whether Iq is above or below the average Ic of a long piece of conductor and their ratio Iq/Ic,ave, greatly affecting quench detection and thermal runaway prevention strategies of Bi-2212 and REBCO magnets.

Mosat, Marek↗
DOE OSTI2026

Gas-driven short disconnection mitigates thermal runaway in Li-ion batteries under mechanical abuse

Mechanical abuse poses a critical safety risk to Li-ion batteries by inducing internal short circuits that initiate thermal runaway. Remarkably, voltage recovery frequently emerges during thermal runaway initiation, a phenomenon that conventional theories fail to explain. Here, our study develops a new multiphysics mechanism to explain voltage recovery, termed gas-driven short disconnection, whereby internal gas pressure mechanically disengages short-circuit contacts and causes the cell voltage to rebound. This mechanism incorporates gas generation and its structural impact on the short circuit. Real-time optical and thermal imaging and X-ray computed tomography reveal fluid-structure interaction between internal gas flow and adjacent shorting contacts. We establish a mechanistic framework linking gas-driven short disconnection to cell-level voltage and temperature responses, elucidating the extension–truncation pattern of voltage recovery. Furthermore, thermal regime maps show that a voltage recovery duration exceeding 5 s correlates with limited temperature rise below 150 °C, indicating that sustained short-circuit disconnection suppresses Joule heating. Additionally, a dimensionless criterion is deduced from scaling analysis for physical plausibility of gas-driven short disconnection in mechanically abused cells. This finding inspires smart venting control, which regulates gas release to maintain the internal pressure while dissipating gas enthalpy, thereby providing a device-level strategy for thermal runaway mitigation.

Gas-driven short disconnection↗
DOE OSTI2021

Unlocking the self-supported thermal runaway of high-energy lithium-ion batteries

Layered Ni-rich LiNi x Mn y Co 1-x-y O 2 (NMC) materials are the most promising cathode materials for Li-ion batteries due to their favorable energy densities. However, the low thermal stability typically caused by detrimental oxygen release leads to significant safety concerns. Determining the pathways of oxygen evolution reaction is essential, as the ideal safety countermeasure is to break the reaction chain of thermal runaway. In this study, we demonstrate that two endogenous pathways of oxygen involved in strong exothermic reactions lead the NMC811|graphite pouch cell to an uncontrollable state, and we quantify the individual contribution of the pathways to thermal runaway. Approximately 41% of thermal-induced oxygen reacts aggressively with ethylene carbonate (EC) at the cathode/electrolyte interface with 16% heat generation, accelerating the self-heating rate and thereby further triggering thermal runaway. The residual oxygen that survives the reaction with carbonate spreads to the lithiated anode with major heat generation (65%), bringing the battery to the maximum destructive temperature during thermal runaway. By confirming the significant roles of EC and anode, a deeper understanding on battery fire was achieved. Finally, the revealed mechanism can help guide studies on stopping the two reaction pathways, allowing for the safer use of high-energy lithium-ion batteries in the future.

25 ENERGY STORAGE↗
DOE OSTI2023

Sidewall Breach During Lithium-Ion Battery Thermal Runaway Triggered by Cell-to-Cell Propagation Visualized Using High-Speed X-Ray Imaging

With the rapid deployment of Li-ion batteries (LiBs) in a range of applications, it is crucial to ensure their safe operation. Therefore, it is necessary to investigate the rapid thermal runaway failure that LiBs can undergo if improperly operated or subjected to abuse scenarios so that hazardous events can be avoided or mitigated. Sidewall breaches or ruptures of LiBs during thermal runaway are considered the most hazardous failure scenario, resulting in hot abrasive flare from the casing of the cell that can impinge on neighbouring cells and lead to the propagation of thermal runaway throughout a battery pack. Yet, the process leading up to the sidewall breach is not well understood due to the extreme difficulty in visualizing such a failure in commercially relevant cells. With the application of a newly developed chamber for remote-controlled abuse testing of batteries coupled with simultaneous X-ray imaging, we demonstrate here for the first time an in-situ visualization of a sidewall breach. By further applying spatiotemporal mapping techniques, the internal thermal runaway events leading up to the sidewall breach can be analyzed in detail. Subsequently, the speed of the electrode layer delamination could be calculated to a speed of 0.6 m/s. These new insights bring more clarity regarding this phenomenon, that in turn can help battery designers improve battery safety.

battery safety↗