UL 9540A large-scale fire test requirements met

No thermal runaway in adjacent container battery cells

North America, domestic ESS market push accelerates

SK On's energy storage system on display. [SK On]
SK On's energy storage system on display. [SK On]

SK On said Wednesday it has completed a large-scale fire test for its energy storage system (ESS) and satisfied the evaluation requirements of UL 9540A, the North American safety testing standard for ESS.

UL 9540A is a testing standard that measures how heat spreads to surrounding areas when a battery undergoes thermal runaway. Its large-scale fire test (LSFT) replicates actual ESS fire conditions to verify whether fire spreads to adjacent containers. The standard's detailed requirements were tightened in March to provide clearer criteria for assessing fire propagation.

Test results showed no thermal runaway in battery cells inside containers adjacent to the one where the fire originated, and internal container temperatures met the evaluation benchmarks. SK On said it designed its ESS to disperse and release heat gradually over an extended period, suppressing sudden spikes in heat release rates and reducing the likelihood of fire spreading to neighboring containers.

SK On plans to accelerate its push into the global ESS market on the back of the UL test report. The company signed a supply agreement for lithium iron phosphate (LFP) batteries for ESS with US-based ESS firm Neovolta Power in August, and in September last year concluded a 1 gigawatt-hour ESS supply contract with US renewable energy company Flatiron.

The company is also stepping up its pursuit of the domestic market. At the second centralized contract market held in February, SK On secured 284 megawatts — more than half of the total 565 megawatts on offer. It is also converting 3 gigawatt-hours of the 7 gigawatt-hours of total production capacity at its factory in Seosan, South Chungcheong Province, into dedicated LFP battery lines for ESS.

"This test confirmed that SK On's ESS can suppress fire spread and maintain key safety performance even under actual fire conditions," a company official said. "We will continue to strengthen our safety technology and product competitiveness to provide customers with tailored ESS solutions and expand our presence in the global market."

Meanwhile, SK On recently held its second Future Technology Institute Academic Conference at the SK On Future Technology Institute in Yuseong-gu, Daejeon, sharing research findings across six areas — battery processes, cells, systems, materials, next-generation technology and platforms — as part of its broader efforts to strengthen its next-generation battery technology capabilities.


eyre@heraldcorp.com