Batteries as an energy storage device have existed for more than a century. With progressive advancements, the capacities have ramped up to a point where battery energy storage can suffice to power a home, a building, a factory, and even to supplement the grid.
The capability to supply this kind of energy is accomplished through battery energy storage systems (BESS). Lithium-ion and lead acid batteries are both currently being used for large-scale energy storage. However, lithium-ion installations command 90% market share worldwide for BESS use.
This animation shows how a Stat-X® condensed aerosol fire suppression system functions and suppresses a fire in an energy storage system (ESS) or battery energy storage systems (BESS) application with our electrically operated generators and in a smaller modular cube style energy storage unit with our thermally activated generator.
Lithium-ion batteries, in simple terms, contain a positive and negative anode. Lithium ions move from the negative anode to the positive anode during discharge and back when charging. This mechanism is immersed in an ion-conducting electrolyte. The electrolyte is a combustible/flammable liquid.
Taken together in a housing or container, the lithium-ion batteries are called “cells.” BESS can contain dozens, hundreds, or even thousands of cells to store energy. The cells are typically held in racks, and the racks are normally stored in shipping-container-type structures. Obviously, residential models are much smaller and are often installed in a home garage or basement.
Lithium-ion BESS provide a high energy density in a small, lightweight package. Furthermore, they are low maintenance and, for the most part, safe. Until a better solution for energy storage is developed, lithium-ion BESS are here to stay and will only see increased usage.
Anytime you pack high levels of energy into a small space, there is risk. The energy wants to get out, and when it does so in an uncontrolled fashion, the results can be dramatic—in a bad way. A single lithium-ion cell poses this risk. Exhibit A: exploding cell phone. Exhibit B: exploding cell phone.
Consider that there can be hundreds of cells stored together in a shipping container. With that kind of quantity, the risk of a major incident increases dramatically. But in industrial applications there can be many multiples of these shipping containers on site in close proximity to each other; the risk just went up exponentially.
The risk involved with BESS has not gone unnoticed by agencies that promulgate safety standards in energy storage installations. The following standards have been published with more on the horizon:
Underwriters’ Laboratories, Inc.®
National Fire Protection Association (NFPA®)
To manage the risks associated with BESS, it is important to understand what happens when a lithium-ion cell fails. Cell failure occurs in stages.
Thermal runaway is the catastrophic component of cell failure. During thermal runaway, the following occurs:
Fires involving BESS are problematic, for several reasons:
Given the difficult nature of BESS fires, not just any fire suppression agent is suitable for the task. Fortunately, a solution is at hand—Stat-X condensed aerosol fire suppression. Stat-X is proven to be effective on lithium-ion battery fires through extensive third-party testing. It offers many advantages over other fire suppression methods such as sprinkler and gaseous systems.
Fireaway has undergone two separate and independent testing programs focused on the BESS hazard.
First, Fireaway contracted DNV GL (now known as DNV), an international leader in testing, to conduct trials of Stat-X on lithium-ion battery fires. The results were extremely positive:
Second, Fireaway contracted PVEL, a leader in renewable energy product and regulatory testing, in conjunction with multiple subject matter experts in the BESS testing field, to perform full-scale testing in compliance with UL 9540A. These results were also positive. During the period of Stat-X discharge and agent hold:
This fire test demonstrates a Stat-X condensed aerosol fire suppression system on a li-ion battery module in a Battery Energy Storage System (BESS) application.
Stat-X condensed aerosol offers numerous advantages over legacy-type fire suppression systems in BESS fires. The effectiveness of condensed aerosol application is additionally addressed in NFPA 2010: Standard for Fixed Aerosol Fire Extinguishing Systems®.
Users deploying Stat-X in their BESS installations will realize the following features and benefits: