# SK On passes UL 9540A fire safety test for utility storage *The battery maker satisfied tightened North American container propagation rules without cell runaway in adjacent units, backing 10 gigawatt-hours of utility supply deals.* **Published:** October 29, 2026 **By:** Seung-min Park **Section:** Batteries & Electric Vehicles — South Korea **Format:** Breaking **Confidence:** medium **Source:** https://eastasiabrief.com/batteries-ev/sk-passes-ul-9540a-fire-safety-test-utility-storage-979 **Publisher:** East Asia Brief (https://eastasiabrief.com/) --- ## What to know - SK On clears UL 9540A large-scale fire test without adjacent container propagation - NeoVolta five-year contract locks in 9 GWh from Georgia plant starting 2027 - Domestic tender for roughly 1 GW opens before year-end ![A technician holds a tablet while inspecting battery modules on racks inside an energy storage facility. (AI-generated image)](https://eastasiabrief.com/media/2026-10-28-69ab11d2f73c.webp) *A technician holds a tablet while inspecting battery modules on racks inside an energy storage facility. (AI-generated image)* SK On said Oct. 28 it passed the large-scale fire test under North American standard UL 9540A, clearing container-level safety evaluations for utility battery installations. The South Korean battery maker satisfied the fire test after securing 284 megawatts, or 50.3% of the 565 megawatts auctioned in South Korea's second central energy storage tender in February. Global testing organization CSA conducted the simulated fire trial under revised criteria implemented in March. The updated rules established stricter benchmarks for assessing flame containment and heat transfer between neighboring storage enclosures. The protocol evaluated large-scale fire propagation across full industrial units. Testing verified that intense heat inside an ignited container failed to ignite battery packs in an adjacent container enclosure. Battery cells in neighboring containers did not experience thermal runaway — an uncontrollable self-heating reaction inside a cell — during the test, the company said. Temperatures inside those adjoining units remained within certification limits. SK On credited the test outcome to an internal thermal architecture that releases heat gradually over long intervals. The slow dispersion design curbs sudden increases in heat release rates during emergency events. The containment method lowers the probability that flames or radiant energy will compromise adjacent modules. Preventing enclosure-to-enclosure spread allows power providers to install battery containers closer together on constrained utility sites. Fire safety rules have become the primary hurdle in North American and European grid procurements. Regional permitting authorities enforce standards such as NFPA 855, which govern installation clearances and fire suppression in stationary storage facilities. Chinese battery makers including Contemporary Amperex Technology dominate international utility storage installations using prismatic lithium iron phosphate cells. South Korean producers are adapting pack insulation to prove pouch cells meet comparable safety thresholds. The certification supports commercial deployment of SK On's dedicated grid storage brand, GRIDON, which the manufacturer unveiled in Texas in June. The brand targets utility-scale renewables integration and industrial backup systems. SK On reached a major supply agreement in August with U.S. storage developer NeoVolta Power for nine gigawatt-hours of lithium iron phosphate pouch cells. Deliveries to NeoVolta Power will span five years from 2027 through 2031, SK On said. The contract carries an estimated market value of about 1.5 trillion won ($1.09 billion). The batteries will come from SK On's manufacturing facility in Georgia. NeoVolta Power will integrate those cells at its production site in Pendergrass, Georgia, to build complete containerized systems. Both companies are pursuing a separate agreement before year-end for an additional nine gigawatt-hours. The expanded collaboration would lift cumulative battery shipments between the two firms to 18 gigawatt-hours. The NeoVolta transaction accounted for nearly half of SK On's stated objective to win 20 gigawatt-hours of energy storage contracts this year, the company said. That transaction followed a September 2025 supply contract with U.S. developer Flatiron Energy Development for one gigawatt-hour of containerized storage products. The supply term for Flatiron runs through 2029. SK On also secured preferential negotiation rights on an additional 6.2 gigawatt-hours of projects that Flatiron is developing. If realized, the total Flatiron arrangement could reach 7.2 gigawatt-hours worth two trillion won ($1.45 billion). The battery maker is reconfiguring domestic manufacturing capacity to align with expanding grid demand. At its factory in Seosan, South Chungcheong Province, the company is converting three gigawatt-hours of capacity. The conversion shifts three gigawatt-hours of the plant's seven-gigawatt-hour total footprint into dedicated production lines for energy storage cells. The lines will make lithium iron phosphate batteries rather than automotive chemistry. Repurposing production lines in South Korea and the United States helps balance plant utilization rates, analysts said. Softer growth in global electric vehicle purchases has left high-nickel automotive lines running below designed capacity. SK On plans to submit bids for South Korea's third central energy storage market tender later this year. The domestic procurement round will auction approximately one gigawatt of grid capacity. The test announcement does not disclose the formal expiration date of the UL 9540A report. Certification agency CSA has also not published the complete technical test dossier to the public. ## Impact map | Event | Korea | China | Japan | Global impact | | --- | --- | --- | --- | --- | | UL 9540A fire test clearance | SK On secures 284 MW in auction and converts 3 GWh at Seosan plant | Contemporary Amperex Technology faces direct safety competition in North American grid RFPs | utilities and integrators monitor certified container designs for imported systems | grid developers gain UL-verified containment option to meet NFPA 855 siting rules | ## In this story - **Companies:** SK On - **Exposed:** Contemporary Amperex Technology, NeoVolta Power, Flatiron Energy Development - **Policy:** Standards - **Impact:** Compliance, Supply Chain, Order Book ## Primary sources 1. ddaily.co.kr 2. finance-scope.com 3. joseilbo.com 4. koreatimes.co.kr 5. fnnews.com --- Cite as: East Asia Brief, "SK On passes UL 9540A fire safety test for utility storage," October 29, 2026. https://eastasiabrief.com/batteries-ev/sk-passes-ul-9540a-fire-safety-test-utility-storage-979