A review of lithium ion battery failure mechanisms and fire prevention strategies

Lithium ion batteries (LIBs) have transformed the consumer electronics (CE) sector and are beginning to power the electrification of the automotive sector. The unique requirements of the vehicle ap...

Opportunities and Challenges of Lithium Ion Batteries in Automotive Applications

Over the last decade, the electric vehicle (EV) has significantly changed the car industry globally, driven by the fast development of Li-ion battery technology. However, the fire risk and hazard associated with this type of high-energy battery has become a major safety concern for EVs. This review focuses on the latest fire-safety issues of EVs related to thermal runaway and fire in Li-ion batteries. Thermal runaway or fire can occur as a result of extreme abuse conditions that may be the result of the faulty operation or traffic accidents. Failure of the battery may then be accompanied by the release of toxic gas, fire, jet flames, and explosion. This paper is devoted to reviewing the battery fire in battery EVs, hybrid EVs, and electric buses to provide a qualitative understanding of the fire risk and hazards associated with battery powered EVs. In addition, important battery fire characteristics involved in various EV fire scenarios, obtained through testing, are analysed. The tested peak heat release rate (PHHR in MW) varies with the energy capacity of LIBs ($$E_{B}$$ in Wh) crossing different scales as $$PHRR = 2E_{B}^{0.6}$$. For the full-scale EV fire test, limited data have revealed that the heat release and hazard of an EV fire are comparable to that of a fossil-fuelled vehicle fire. Once the onboard battery involved in fire, there is a greater difficulty in suppressing EV fires, because the burning battery pack inside is inaccessible to externally applied suppressant and can re-ignite without sufficient cooling. As a result, an excessive amount of suppression agent is needed to cool the battery, extinguish the fire, and prevent reignition. By addressing these concerns, this review aims to aid researchers and industries working with batteries, EVs and fire safety engineering, to encourage active research collaborations, and attract future research and development on improving the overall safety of future EVs. Only then will society achieve the same comfort level for EVs as they have for conventional vehicles.

A review of battery fires in electric vehicles

Lithium-ion battery fires generate intense heat and considerable amounts of gas and smoke. Although the emission of toxic gases can be a larger threat than the heat, the knowledge of such emissions is limited. This paper presents quantitative measurements of heat release and fluoride gas emissions during battery fires for seven different types of commercial lithium-ion batteries. The results have been validated using two independent measurement techniques and show that large amounts of hydrogen fluoride (HF) may be generated, ranging between 20 and 200 mg/Wh of nominal battery energy capacity. In addition, 15–22 mg/Wh of another potentially toxic gas, phosphoryl fluoride (POF3), was measured in some of the fire tests. Gas emissions when using water mist as extinguishing agent were also investigated. Fluoride gas emission can pose a serious toxic threat and the results are crucial findings for risk assessment and management, especially for large Li-ion battery packs.

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Toxic fluoride gas emissions from lithium-ion battery fires

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The Future of Flame Retardant Polymers – Unmet Needs and Likely New Approaches

Heat release during thermally-induced failure of a lithium ion battery: Impact of cathode composition

Lithium ion batteries (LIBs) are efficient, high-density electrical energy storage devices utilized in a perpetually increasing range of applications. One of the weaknesses of LIBs is that a small deviation from the normal operating conditions may cause an irreversible failure accompanied by a rapid self-heating and ejection of combustible gases and aerosols. The information on how much energy is released upon failure is critical for design of energy storage systems. In the current study, a novel technique, Copper Slug Battery Calorimetry (CSBC), was combined with oxygen consumption calorimetry to measure the rate of heat generated inside an LIB cell (PIHG) and the rate of heat generated as a result of combustion of ejected battery materials (PFlaming). A short duct equipped with a perforated plate was added to the original design of the CSBC apparatus to collect gases and aerosols ejected from the cell, reduce their flow speed and deliver them to a hot-wire igniter, which was used to initiate a diffusion flame. The exhaust from this flame was collected to measure the oxygen consumed in the combustion process and compute PFlaming. This approach to handling the ejected materials increased their combustion efficiency and eliminated thermal feedback from the flame to the cell, which enabled simultaneous measurement of PIHG and PFlaming. The new setup was employed to investigate thermally induced failure of an 1880 mA h prismatic LIB at various states of charge (SOC). It was determined that, at 100% SOC, this LIB released 33 ± 1.0 kJ of energy into the body of the cell and 113 ± 19 kJ was produced as a result of combustion of the ejected battery materials. The latter value is significantly greater than those previously reported for similarly sized cells, which can be explained by a more complete combustion achieved in this new apparatus.

Simultaneous measurement of multiple thermal hazards associated with a failure of prismatic lithium ion battery

This study outlines a general methodology to develop a thermo-kinetic model of thermally-induced failure for a lithium ion battery (LIB) using COMSOL multiphysics software and experimental data collected with the Copper Slug Battery Calorimetry (CSBC) This methodology is demonstrated by developing the model for a specific type of LIB - T-Energy ICR18650 CSBC tests were conducted on the sample LIB cells to determine the thermal transport parameters and global reaction kinetics associated with the cells' thermal failure The model was parameterized primarily via an iterative inverse modeling analysis of the CSBC test results The parameters include heat capacity and density of the cell, radial thermal conductivity of the cell, and the Arrhenius parameters and heat of reaction representing the process of thermal runaway The reaction parameters were related to the cell's state of charge using empirical functions interpolating these parameter values The fully-parameterized thermo-kinetic model was then validated against CSBC tests that were conducted under conditions not utilized in the model parameterization process Subsequently, this model was applied to predict the thermally-induced failure of LIB cells in a more complex scenario: cascading failure of 6 LIB cells in a "billiard rack" configuration The simulated time of onset of thermal runaway of each sequentially failing LIB cell was found to be in a good agreement (within 9%, on average) with the corresponding experimental observations

Zhibo Wu

Papers

Heat release during thermally-induced failure of a lithium ion battery: Impact of cathode composition

Simultaneous measurement of multiple thermal hazards associated with a failure of prismatic lithium ion battery

A Thermo-Kinetic Model of Thermally-Induced Failure of a Lithium Ion Battery: Development, Validation and Application