S&C Reports on Li-Battery Fire at Its Franklin Facility

On August 10, 2016, S&C Electric had a fire in the assembly area of its Franklin, Wisconsin, facility. The company recently released a detailed report on the causes and impacts of that fire. The fire began in a utility-scale energy storage system that was in a partially assembled state. This partially assembled system contained lithium-ion batteries. These batteries were not being charged or discharged and were not connected to a power source or load. The fire began when an agent of the battery manufacturer was working on the energy storage system. The fire started in one of that battery manufacturer's dc power and control compartments of a battery rack within the energy storage system, and once the fire was started in the battery rack dc power and control compartment it spread to the adjacent batteries.

David Myers, Vice President, Power Quality & Energy Storage with S&C and author of the report stated, “Let me start by saying the fire in our Franklin facility was not caused by the spontaneous thermal runaway of a lithium-ion battery. I bring this up first because it is extremely important to be clear on this fact because the energy storage industry, and the general public, have questions regarding the safety of lithium-ion batteries; whether they are in a substation, our cars, or our electronics.”

“Battery energy storage on the electric grid is a relatively new technology, and the pace in which technologies are being introduced to the market is rapid. This means systems require careful engineering, integration, installation, operation, and maintenance to minimize the safety risks, especially fire. This starts with the energy storage system design. For over a decade, S&C has been applying a “5-Points” approach to energy storage system safety.

“This approach proved invaluable in helping contain the fire and minimize the impact to the affected system, to other equipment being assembled, to our Franklin Facility, and most importantly to our team members. For example, despite the batteries burning in the same container as our power conversion system inverters, our inverters were relatively undamaged.

“This is remarkable given the partially assembled nature of the system. S&C’s 5-Points approach to battery energy storage system safety ensures that safety measures are in place within the system’s: 1) Intelligent Controls (Battery and Power Conversion System); 2) Protective Devices (Fuses, Ac Circuit Breakers, Dc Circuit Breakers); 3) Fire Suppression Systems; 4) System Design (Power Conversion System, Battery Components and Systems, Compartmentalization, and Containerization); 5) Container.

“As noted earlier, given that our system was still in assembly, it does not represent what would be present in a fully integrated field installation. As a result, these points were not fully operational. Despite that, the work we put into the compartmentalized and containerized design of our Power Conversion System and Battery Container Design proved essential in containing the fire. The system that experienced the fire was designed with its power conversion system isolated from all battery racks by a walled barrier. This designed isolation system limited the spread of the fire and kept it contained to the battery racks despite the fact that the container was not sealed and the container’s fire-suppression system was not operational.

Mr. Myers continued by observing: “One of the qualities that sets S&C apart from other companies is that, rather than hide an issue, we want to bring it to light and learn from it. The reason I wrote this article is so S&C’s experience can help the industry, customers, and the public learn from the fire we had. This sharing of information can help progress the energy storage industry even further and faster.

“LESSON 1: Give thanks – We can’t express enough how thankful we are for our first responders. Our local fire department showed up in minutes and quickly mobilized other local fire departments and the local police to ensure our team members and community were kept safe. Their hard work and preparation are often overlooked until we have a time of need. I was humbled by the organization and support our first responders demonstrated both during the incident and during the investigation. If you haven’t done it lately, take a moment to thank a first responder for their service next time you see one.

“LESSON 2: We need better information on fighting battery fires – There is still work that needs to be done between battery manufacturers and fire-protection agencies to determine the best ways to contain, and if possible, put out battery fires. Material safety data sheets are not enough, especially as batteries spread throughout the grid and new chemistries are developed. Even if S&C’s safety approach is followed, fire departments around the world need more training to understand what these systems are and how to address them.

To this end, S&C is sharing details and best practices regarding our fire with members of the National Fire Protection Association (NFPA) who are developing energy storage system training for fire service members. The goal of this training is to use examples such as ours as teaching tools for the NFPA’s classroom programs that will teach firefighters how to safely respond to lithium-ion battery incidents. Additionally, because battery technologies are rapidly changing, we will be working with our local fire department to inform it of new batteries before they arrive at our facility.

“LESSON 3: Being a system integrator was essential – There is immense value in being an energy storage system integrator instead of just a packager. Individual energy storage subsystem vendors understand how to protect their individual subsystems, whether it’s the battery, power conversion system, or software. But they miss what is needed to safeguard and protect a fully integrated system. Companies that merely package energy storage systems focus only on what components are needed to build an energy storage system, but they don’t understand how the protection schemes of these different systems need to work together to effectively minimize the risk of the system as a whole not working properly.

“What proved most valuable in this event was S&C’s expertise as an integrator, which allowed us to understand all the systems involved in our assembly and how they needed to come together to minimize risk. This energy storage integration expertise directly led to our fire being contained quickly, which minimized the impact to our Franklin operations and ensured no S&C team members were hurt,” Myers concluded.