Over the last few years, the use of lithium-ion batteries has increased significatntly. At the same time, there have been many news stories about fires and explosions cause by lithium batteries. As a precaution, TSA has implemented restrictions on these batteries on airplanes. Similarly, there has been an increase in the manufacturing and industrial use of these batteries. With this trend, it is important that companies become aware of the health and safety hazards of lithium-ion batteries.
The lithium-ion cathode is made of lithium metal oxide. Metals may include cobalt, manganese, nickel, lithium, aluminum oxide, and/or iron phosphate. During the manufacturing and handling of these materials the components may become air-borne in the form of respirable dusts which employees may inhale. Acute exposure to hazardous metals can result in eye, nose, and throat irritation, fever, chills, headache, nausea, shortness of breath, muscle pain, and a metallic taste in the mouth. Chronic exposure can result in respiratory effects including coughing, wheezing, skin sensitization, and decreased pulmonary function. Various metals can affect specific target organs as well.
Other hazardous components of lithium-ion batteries include salts such as hexafluorophosphate which can react with moisture to form hazardous acidic compounds such as hydrogen fluoride, a highly toxic and corrosive gas. Organic solvents such as methyl-2-pyrrolidone (NMP) can be absorbed through the skin and can have adverse reproductive effects and skin and eye irritation. Inhalation can cause neurological symptoms and chronic overexposure may also impact the kidneys, liver, and immune system. Dusts and nano particles produced in the manufacturing of the batteries may also have respiratory effects.
As already noted, lithium batteries are highly flammable and can catch fire or explode due to thermal runaway. It occurs when internal heat generation exceeds a battery’s ability to dissipate it. This causes the cell’s temperature to rise uncontrollably, accelerating chemical reactions and generating more heat. Eventually, the electrolyte and electrodes can ignite, leading to explosion or combustion. In the manufacturing process, battery components and dusts may be exposed changes in temperature, charging, and pressure.
In order to control the hazards of manufacturing or using lithium batteries, safety should be designed into the process. Following OSHA guidelines and process safety management standard 1910.119 may be required and ANSI and the National Fire Protection standards are also helpful. Reduce employee exposures by using automatic systems that remove the employee from the hazard, use electrolyte vapor detection, thermal runaway protection, install ventilation, follow occupational exposure limits, and provide personal protective equipment.
Lithium-ion batteries are used in many consumer and industrial applications. It is important that the hazards of these batteries be recognized and all available controls implemented to make their use safe.
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