Lithium-ion batteries are energy dense, able to store an ever-increasing amount of electrons in a relatively small space. As the number of devices that they supply power to grows exponentially, it becomes more and more important to understand their chemistries, constructions, and potential limitations. We recently reached out to Brian O’Connor of the National Fire Protection Association for his insights regarding the safety of Lithium-ion batteries.
O’Connor is a fire protection engineer at the National Fire Protection Association (NFPA) and treasurer for the New England Chapter of the Society of Fire Protection Engineers. At the NFPA he is the staff liaison to technical committees covering topics such as aviation, portable extinguishers, water-based protection, and energy storage systems. We’re pleased to share his perspectives here.
Distributed Energy (DE): What materials or mechanisms are the source of most issues with Lithium-ion batteries? What, from your point of view, makes them most volatile?
Brian O’Connor (BO): One mechanism that is the source of most issues with Lithium-ion batteries is thermal runaway. Thermal runaway is a term used to describe the rapid uncontrolled release of heat energy from a battery cell. Basically, this is when a battery creates more heat than it can effectively dissipate. When this occurs it often spreads to adjacent cells causing a cascading effect until the battery explodes or bursts into flames. One issue with thermal runaway is that it is hard to catch early on because the physical signs, such as bulging, are often hidden by several layers of protective covering that usually exists around these batteries.
The electrolytes used in these batteries are made up of Lithium salts, which are extremely flammable and has the potential to release toxic gasses in the event of a failure.
DE: What are some of the Association’s primary concerns when it comes to the safety of batteries?
BO: At the NFPA, we are primarily concerned about preventing death, injury, economic and property loss due to fire, electrical, or related hazards. Specific to Lithium-ion batteries, we want the consumers, first responders, and everyone involved with the manufacture and distribution to be safe.
These batteries have a high energy density which allows them to store a large amount of energy in a small amount of space. Like any product, a small number of these batteries are defective. They can overheat, catch fire or explode.
DE: I understand that you’re currently in the process of developing a set of standards for energy storage. What are some of the specific topics that the standards will address?
BO: NFPA 855 is a standard on energy storage systems that is currently under development. The current scope of this document is minimizing the hazards associated with energy storage systems. It will cover many different types of energy storage systems, including Lithium-ion batteries but will only apply to batteries used in stationary application (not a typical cell phone or laptop battery). It will also only apply to batteries above a certain size. For Lithium-Ion batteries the threshold is 20 KWhr except for residential installations, which the threshold is 1 KWhr.
DE: What steps can consumers take to ensure that their Lithium-ion battery-powered products are safe?
- Purchase and use devices that are listed by a qualified testing laboratory
- Follow the manufacturer’s instructions (Do not abuse batteries)
- Only use the battery that is designed for the device
- Put batteries in the device right away
- Only use the charging cord that came with the device
- Do not charge a device under your pillow, on your bed, or on a couch
- Keep batteries at room temperature
- Do not place batteries in direct sunlight or keep them in a hot vehicle
- Store batteries away from anything that can catch on fire
- Properly dispose of batteries by either taking them to a recycling location or contact your community for disposal instructions
DE: In light of the recent Samsung recall on the Galaxy Note 7, what safety policies do you feel are important for companies and battery producers to uphold?
- Fire testing
- Validation testing
- Protection from impacts and abuse
- Listed by a qualified testing laboratory
- Correct warnings and instructions for use