Gregory Barber, "Big Batteries Are Booming. So Are Fears They'll Catch Fire" https://www.wired.com/story/big-grid-batteries-are-booming-so-are-fears-fire/

« But grid batteries do have their own risks, which some experts say should be better explained to would-be neighbors. Guillermo Rein, a professor of fire science at Imperial College London, says that the industry has done an excellent job making fires rare despite the inherent volatility of lithium-ion technology. But safety measures are still evolving, he adds, and there are significant gaps in our understanding of how to prevent and lessen the impact of the most catastrophic blazes. “We’re playing catch-up,” he says. “The risk is unknown, and it has to be measured.”

SPARKS, ARCS, AND flames are a risk in any electrical system. When they occur in or around a battery, the outcome can be disastrous. When flames warm a battery cell, one of the repeating components of a larger battery, beyond a certain temperature, a chemical reaction begins that produces more heat, triggering the same process in neighboring cells. Thermal runaway can take off in just milliseconds, before smoke or heat can be detected by an alarm system. The fire spreads first within a cluster of surrounding cells that share electronics, known as a module, and then onto others, until a whole rack of batteries is ablaze.

The first layer of fire safety is preventing that initial spark from happening. Most fire testing involves ferreting out faults in individual battery cells—something the industry, which makes millions of those cells each year for all kinds of energy applications, does well, explains Rein. But as they are packed into larger groups for grid-scale systems, testing becomes more complex, and the pathways to ignition multiply: coolant leaks, shorting electronics, faulty installation. Not every pathway is reproducible in the lab, says Rein, who authored a 2020 review of battery safety standards, which he describes as “chaotic.” »

#infrastructure #batteries #renewables #peakrenwables