This article was published by The Energy Mix on Feb. 27, 2024.
By Gaye Taylor
Experts are tackling the battery safety—at a stress-testing lab in Ottawa, and on an interagency panel in New York State that is redefining fire codes to curb potential safety hazards.
“When you abuse batteries, you never really know what’s going to happen,” said Dean MacNeil, describing the mysteries of his work at the National Research Council of Canada (NRC).
As team leader at the NRC’s Montreal Road campus in Ottawa, MacNeil performs battery stress tests in extreme scenarios—finding the right balance between performance and safety.
“Explosions, slashings, crush tests, and cars set on fire. Welcome to the NRC’s battery abuse lab,” writes Electric Autonomy Canada, describing activities at MacNeil’s workplace, where the team is engaged in finding out what can happen when lithium-ion batteries and battery cells are “abused.”
Or, as Electric Autonomy puts it: “What does it look like when you puncture a battery with a nail gun? Crush it, light it on fire, put it in water, freeze it, broil it, slash it, short circuit it, or overheat it from the inside out?”
None of these situations is likely to happen in the real world. “These are extreme scenarios and they’re done for performance reasons,” said MacNeil. “We’ve learned a lot from everything that we’ve done so that we minimize the potential to make mistakes.”
One of the fundamental errors MacNeil and his team help battery developers to avoid is the dangerous phenomenon of “thermal runaway” in an individual battery cell.
“Thermal runaway is lab-speak for a heat-generating reaction within the battery cell that does not (or cannot) dissipate that heat,” explains Electric Autonomy, adding that without proper cooling or containment, battery overheating can cause problems. “These include faster degradation, short circuits, venting, fires and, sometimes, even an explosion.”
Thermal runaway events remain rare outside the lab, in part because lithium-ion batteries are secured in hard casings purpose-built to prevent the kinds of breaches that could lead to uncontrollable exothermic reactions within a battery. But to consider all the contingencies, MacNeil and his team are still “expanding their facility to include a room where they can test a bigger battery configuration—say a fully assembled pack or an entire car,” Electric Autonomy says.
“There’s no simple design for battery abuse testing, we test designs for a wide array of applications,” MacNeil said. “Many times, real world events drive our abuse test designs, but ultimately it is our raison d’être to ensure the fundamental science and engineering of the pack design is safe and, if not, to propose potential solutions.”
The lab has tested cells in popular vehicles for Transport Canada and for private companies, writes Electric Autonomy. For some smaller Canadian players, the lab makes sure their cell technologies are “striking the right balance between cutting edge and cautious.”
“I can’t emphasize it enough: safety is an aspect, but it’s not everything,” MacNeil said. “You have to hit other performance metrics.” Which means that “it’s hitting those other performance metrics, but keeping safety adequate.”
More-than-adequate battery safety is a concern in New York, where the inter-agency Fire Safety Working Group has compiled 15 preliminary recommendations to revise or enhance the state fire code. The working group was convened by Governor Kathy Hochul last year in the wake of a spate of battery energy storage systems (BESS) fires in the state.
Its first recommendation is for the Fire Code of New York State (FCNYS) to “require industry-funded independent peer reviews for all projects,” a tougher form of a current rule that empowers but doesn’t mandate the reviews to go along with developers’ permit applications. The change is urgently needed, the working group says, because local authorities “often lack the resources or expertise to understand and interpret critical BESS permitting documents, particularly [those] which contain product-level test data on which to base important siting decisions and requirements.”
A second recommendation would extend requirements for explosion control to confined spaces like battery enclosures, where flammable gases can accumulate and concentrate. The current rule only requires explosion control measures in rooms or other walk-in or walk-through areas.
The working group wants to see qualified personnel “available for dispatch within 15 minutes and able to arrive on scene within four hours to provide support to local emergency responders” in the event of a battery fire, and calls for a qualified person who is knowledgeable about the project to always be available by phone.
The working group document goes into detail on a series of other recommendations in areas like first responder safety, 24/7 monitoring of battery system data, an end to fire code exemptions for BESS projects owned and operated by power utilities, CCTV monitoring and responders’ access to footage, and new requirements that BESS facilities develop site-specific emergency response plans and provide annual training for local first responders.
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