Editorial Feature

Improving the Safety of Batteries in Underground Coal Mines

The high energy density of rechargeable lithium ion (Li-ion) batteries allow for enhanced storage capabilities and longer runtimes, making this technology one of the most popular options for portable electronic devices.

Underground mining workers often utilize Li-ion batteries to power various safety equipment including cap lamps, hand-held gas detectors, tracking devices and communication tools.

Current Use of Li-Ion Batteries in Coal Mines

The potential for the Li-ion battery thermal runway, a situation in which an increase in the temperature of a battery can lead to flame ignition, requires any mining equipment equipped with these batteries to be declared permissible by the Mine Safety and Health Administration (MSHA). The presence of released methane (CH4) gas and coal dust, both of which result from various coal mining processes, that occurs within the coal mine can also increase the severity of an explosion if an Li-powered device ignites.

Researchers from the National Institute for Occupational Safety and Health (NIOSH) are actively investigating how to standardize quality control tests for permissible Li-ion and Li polymer batteries in coal mining equipment.

Testing Li-Ion Battery Safety

Traditional safety tests for Li-ion batteries can include electrical, mechanical and environmental evaluations, with mechanical integrity crust tests being the most common. A standard crush test involves the application of an external force pushing into the battery cell until an internal short circuit, or spark, is achieved.

The nail penetration test was commonly employed for this type of mechanical evaluation, however the ability of the metal nail to exude its own thermal energy onto the Li cell limits its practicality in safety testing.

NIOSH Improves Li-Ion Battery Safety Tests

In an effort to create a more standardized technique for evaluating the safety of Li-ion batteries, a study by NIOSH developed a method that involved a 90° wedge-shaped plastic fixture to compress the Li cell. By utilizing plastic rather than metal, the Researchers eliminated the applied force’s potential electrical or thermal energy to dissipate onto the tested cell

The plastic material also exhibits a high mechanical strength and rigidity, as well as a high resistance to solvents and chemicals. To further improve the accuracy of the cell crush tests to be specific to coal mining purposes, the Researchers also conducted the tests within a 20 L chamber that was filled with CH4-air to stimulate potential hazardous conditions within a coal mine.

The NIOSH study looked at two Li-ion batteries within the aforementioned test conditions: (1) LG Chem ICR18650S2 LiCoO2 and (2) A123 Systems 26650 LiFePO4 cells. Overall, the A123 cells proved to be much safer as compared to the LG Chem cells within each of the applied crush test conditions.

The LG Chem cells readily ignited when placed within the CH4 chamber, whereas the A123 cells did not ignite in any of its crush tests. Under high-applied pressures, the A123 cells did rupture and produce smoke, however ignition was never found in either of the test chambers.

The results of the NIOSH test suggest that both the plastic wedge test and the incorporation of a CH4 test chamber are more appropriate crush tests for Li-ion battery safety. Under the conditions of the study, the A123 LiFePO4 battery demonstrated greater safety potential under fabricated mining conditions as compared to the LG Chem LiCoO2.

The plastic wedge test proved to be more severe as compared to traditional crush tests, as it allowed for a deeper penetration of the wedge into the cell without the need for greater applied force.

Additional experimental research on Li-ion battery ignition within ambient conditions containing methane gas mixtures must still be conducted in order to fully demonstrate the safety of any Li-ion battery equipment.

NIOSH and other research organizations must also continue to investigate safer battery assemblies, cable protection and ignition safe disconnects to fully protect against a potential mining disaster.

Image Credit:

Veronika Honcova/ Shutterstock.com


  1. “Are Lithium Ion Cells Intrinsically Safe?” T. Dubanieqicz, J. DuCarme. IEEE Journals. (2013). DOI: 10.1109/TIA.2013.2263274.

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.

Benedette Cuffari

Written by

Benedette Cuffari

After completing her Bachelor of Science in Toxicology with two minors in Spanish and Chemistry in 2016, Benedette continued her studies to complete her Master of Science in Toxicology in May of 2018. During graduate school, Benedette investigated the dermatotoxicity of mechlorethamine and bendamustine; two nitrogen mustard alkylating agents that are used in anticancer therapy.


Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Cuffari, Benedette. (2017, October 17). Improving the Safety of Batteries in Underground Coal Mines. AZoMining. Retrieved on June 13, 2024 from https://www.azomining.com/Article.aspx?ArticleID=1366.

  • MLA

    Cuffari, Benedette. "Improving the Safety of Batteries in Underground Coal Mines". AZoMining. 13 June 2024. <https://www.azomining.com/Article.aspx?ArticleID=1366>.

  • Chicago

    Cuffari, Benedette. "Improving the Safety of Batteries in Underground Coal Mines". AZoMining. https://www.azomining.com/Article.aspx?ArticleID=1366. (accessed June 13, 2024).

  • Harvard

    Cuffari, Benedette. 2017. Improving the Safety of Batteries in Underground Coal Mines. AZoMining, viewed 13 June 2024, https://www.azomining.com/Article.aspx?ArticleID=1366.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Your comment type

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.