Toxic gases | Lithium-ion battery a clean future?

Similar to hydrogen fluoride (HF), carbon monoxide (CO) and carbon dioxide (CO2) are common toxic gases that are released in the burning of LIB (Peng et al., 2020 ). CO is one of the two asphyxiant gas in ISO 13571 (Peng et al., 2020).

ISO 13571:2012 establishes procedures to evaluate the life-threatening components of fire hazard analysis in terms of the status of exposed human subjects at discrete time intervals. – (International Organization for Standardization, 2020)

What is an asphyxiant gas?

Asphyxiant gas is a gas that results in hypoxia, the decrease of oxygen level in body tissue (Cleveland Clinic, 2022), by disarranging oxygen in the respiratory system (Gold, 2022). Besides hypoxia, asphyxiant gases will also cause ischaemia and metabolic acidosis (Gold, 2022; Cowled, 2011). Ischaemia causes deficiencies in blood oxygen, glucose and other substances (Cowled, 2011). When the supply of blood is lower than the demand, the body is no longer able to support essential normal functions (Cowled, 2011). The decrease in blood oxygen and other key substances deranges metabolic function which plays a crucial role in converting food and water into energy in the body (Cowled, 2011; Schoeller & Fjeld, 1991). On the other hand, metabolic acidosis is the buildup of acid in the body when the kidney is unable to remove enough acid in time due to failure (Gold, 2022).

Symptoms:

Headaches, vomiting, lethargy, confusion
Loss of appetite
Chest pain
Shortness of breath
Fast heart rate
Loss of consciousness
Cardiac arrest

(Gold, 2022)

The symptoms a person suffers from by inhaling CO vary according to the concentration of CO and the duration they are exposed to. Furthermore, the deleterious effects of CO can be amplified when CO2 is breathed in with CO (Peng et al., 2020). As both of these gases are produced in conjunction with the burning of batteries, the effects of CO will be intensified.

According to CO2 Meter (2023), the duration before CO takes effect significantly reduces when the concentration of CO exceeds 200 ppm (Figure 1).

Figure 1: Carbon monoxide levels chart (CO2 Meter, 2023)

Burning behaviours of a 68 Ah battery (Figure 2) was studied by Peng et al. (2020) at different state of charge (SOC) and the concentration of CO and CO2 released over time was studied (Figure 3).

Figure 2: 68 Ah lithium iron phosphate battery (Peng et al., 2020)

Figure 3: Experimental setup (Peng et al., 2020)

Batteries at a higher SOC produced the maximum CO and CO2 in the shortest duration after the battery started burning (Peng et al., 2020) (Figure 4). CO production reached a maximum of 258 ppm for 100% SOC albeit for a very short duration (Peng et al., 2020).

Figure 4: Graphs of CO and CO2 production (Peng et al., 2020)

Although this concentration of CO will not have immediate health impacts when exposed to such a short period of time (Figure 1), we must bear in mind that this experiment used a 68 Ah battery with a nominal voltage of 3.22 V (Peng et al., 2020). According to E.ON, (n.d.), the battery capacity of an electric car (EV) is around 40 kWh with some going as high as 100 kWh and the common voltage of the batteries are 280 V and 360 V (Matsusada Precision Inc., 2019). A battery with a capacity of 40 kWh and voltage of 280 V will have a current of 143 Ah, more than double the current of the battery used in the experiment. Burning this battery will most likely increase the concentration of CO and CO2 produced to a lethal concentration that is fatal within minutes of exposure (Figure 1).

Reference List

Cleveland Clinic. (2022). Hypoxia: Causes, Symptoms, Tests, Diagnosis & Treatment. https://my.clevelandclinic.org/health/diseases/23063-hypoxia#:~:text=Hypoxia%20is%20low%20levels%20of,Hypoxia%20can%20be%20life%2Dthreatening

CO2 Meter. (2023, January 23). Carbon Monoxide Levels Chart. https://www.co2meter.com/blogs/news/carbon-monoxide-levels-chart

Cowled, P. (2011). Pathophysiology of Reperfusion Injury. Mechanisms of Vascular Disease – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK534267/#:~:text=Ischaemia%20occurs%20when%20the%20blood,begin%20during%20this%20ischaemic%20phase

E.ON. (n.d.). Electric vehicles | Battery | Capacity and Lifespan. https://www.eonenergy.com/electric-vehicle-charging/costs-and-benefits/battery-capacity-and-lifespan.html#:~:text=The%20average%20capacity%20is%20around,higher%20the%20kWh%20the%20better

Gold, A. (2022, September 26). EMS Asphyxiation And Other Gas And Fire Hazards. StatPearls – NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK519487/

International Organization for Standardization. (2020). ISO 13571:2012. ISO. https://www.iso.org/standard/56172.html

Matsusada Precision Inc. (2019, June 4). Power Supply and Voltage of EV Motor | Tech | Matsusada Precision. Matsusada Precision. https://www.matsusada.com/column/ev-power.html#:~:text=Lithium%2Dion%20batteries%20are%20the,connected%20in%20series%20and%20parallel

Peng, Y., Yang, L., Ju, X., Liao, B., Ye, K., Li, L., Cao, B., & Ni, Y. (2020). A comprehensive investigation on the thermal and toxic hazards of large format lithium-ion batteries with LiFePO4 cathode. Journal of Hazardous Materials, 381, 120916. https://doi.org/10.1016/j.jhazmat.2019.120916

Schoeller, D. A., & Fjeld, C. R. (1991). Human Energy Metabolism: What Have We Learned from the Doubly Labeled Water Method? Annual Review of Nutrition, 11(1), 355–373. https://doi.org/10.1146/annurev.nu.11.070191.002035

Today, lithium-ion batteries (LIB)/ grid-scale battery storage is one of the fastest-growing energy storage systems globally with China, US and Europe leading the market (Schoenfisch & Dasgupta, 2022) (Figure 1). Although the global economy plunged in 2020 due to the COVID pandemic, the battery market continued to grow exponentially. Between 2020 and 2021, the grid-scale battery storage market saw an annual increase of over 60% in global storage capacity (Schoenfisch & Dasgupta, 2022).

Figure 1: Annual grid-scale battery storage additions and distribution (Schoenfisch & Dasgupta, 2022)

In spite of the rapid growth in grid-scale battery storage, the global capacity remains undesirably low should we want to reach a net zero scenario. To meet the goal, Schoenfisch & Dasgupta (2022) estimate that the global grid-scale battery storage capacity will have to increase to 680 GW by 2030 (Figure 2).

Figure 2: Required annual increase of gird-scale battery storage to meet the net zero scenario (Schoenfisch & Dasgupta, 2022)

Although LIB is an excellent alternative and direction towards a low-carbon future, the gaps and problems these batteries continue to plague the industry. The most pressing problem these batteries have today is their sensitivity to high temperatures and susceptibility to burn (Ghiji et al., 2020) (Figure 3). There are a few ways a LIB can be ignited, they include short-circuit, overcharging, exposure to high temperature, mechanical stress and more (Larsson et al., 2017). The hazardous nature of these batteries is particularly risky when used in vehicles such as electrical vehicles and aeroplanes (Ghiji et al., 2020).

Figure 3: Electric car on fire (Ghoshal, 2021)

According to Larsson et al. (2017), the electrolyte of LIBs often contains lithium hexafluorophosphate (LiPF6) or other Li-salts containing fluorine, which are highly flammable and reactive compounds (Guo et al., 2020). Furthermore, fluorine is commonly found in other parts of the LIB in components such as fire retardants and electrodes (Larsson et al., 2017). Being one of the lightest and most reactive metals, this makes LIBs extremely vulnerable to high temperatures and combustion.

Besides the immediate thermal damage from burning, LIBs also release toxic gases such as carbon monoxide (CO) and hydrogen fluoride (HF) (Zhang et al., 2022). The decomposition of LiPF6 is further exacerbated when water is used as an extinguisher (Larsson et al., 2017).

LiPF6 → LiF + PF5 – (1)

PF5 + H2O + → POF3 + 2HF – (2)

LiPF6 + H2O → LiF + POF3 + 2HF – (3)

Additionally, the composition of toxic gases released between different batteries varies according to the particular chemical composition and state of charge (SOC) of each battery (Larsson et al., 2017). The volume and threat of toxic gases released are also larger for bigger cell packs (Larsson et al., 2017). When a large amount of electrolyte evaporates when batteries are heated, this gas may not ignite immediately when released but may accumulate and result in gas explosions at later stages (Larsson et al., 2017).

In the coming blogs, I will explore the toxic gases produced from the combustion of LIBs in detail so stay tuned for more!

Reference List

Ghiji, M., Novozhilov, V., Moinuddin, K., Joseph, P., Burch, I. A., Suendermann, B., & Gamble, G. (2020). A Review of Lithium-Ion Battery Fire Suppression. Energies, 13(19), 5117. https://doi.org/10.3390/en13195117

Ghoshal, A. (2021, December 15). How Lithium Ion batteries in EVs catch fire – Adreesh Ghoshal – Medium. Medium. https://adreesh-ghoshal.medium.com/how-lithium-ion-batteries-in-evs-catch-fire-9d166c5b3af1

Guo, F., Ozaki, Y., Nishimura, K., Hashimoto, N., & Fujita, O. (2020). Influence of lithium salts on the combustion characteristics of dimethyl carbonate-based electrolytes using a wick combustion method. Combustion and Flame, 213, 314–321. https://doi.org/10.1016/j.combustflame.2019.12.001

Larsson, F., Andersson, P., Blomqvist, P., & Mellander, B. (2017). Toxic fluoride gas emissions from lithium-ion battery fires. Scientific Reports, 7(1). https://doi.org/10.1038/s41598-017-09784-z

Schoenfisch, M., & Dasgupta, A. (2022, September). Grid-Scale Storage – Analysis – IEA. IEA. https://www.iea.org/reports/grid-scale-storage

Zhang, L., Duan, Q., Meng, X., Jin, K., Xu, J., Sun, J., & Wang, Q. (2022). Experimental investigation on intermittent spray cooling and toxic hazards of lithium-ion battery thermal runaway. Energy Conversion and Management, 252, 115091. https://doi.org/10.1016/j.enconman.2021.115091

Lithium-ion battery a clean future?

Category Archives: Toxic gases

Toxic gases released during the burning of Lithium-ion batteries (CO and CO2)

Toxic gases released during the burning of Lithium-ion batteries