SolaX Power’s ORI 5 MWh large-scale energy storage system recently completed a full-scale system-level deflagration test with real cells under the UL 9540A:2025 proposal framework, with UL Solutions directly involved in the test design, execution, and assessment. This marks the first system-level deflagration test conducted globally by UL under this proposed framework.
Under controlled conditions, real battery cells were intentionally driven into thermal runaway, with the emergency ventilation system kept closed throughout. The ORI 5 MWh system then went through the full sequence of flammable gas release, build-up, and deflagration, covering the key risk chain used in system-level safety assessment.
The test site, system set-up, and operating conditions were planned by UL Solutions based on simulation work and were designed to represent a highly demanding scenario. The trigger point was placed in an area where pressure waves and flame turbulence can develop more strongly, increasing the challenge for structural integrity and pressure-relief pathways.
Test observations showed that during the deflagration event:
- The pressure-relief structure activated as designed
- Container doors remained closed throughout the event, with no significant deformation observed
- The container structure remained intact, with no rupture
- No components or structural fragments were ejected
- No additional risks to surrounding personnel or the environment were identified
The test was designed to optimize both the severity and realism of the deflagration scenario. The use of real lithium-ion battery cells introduced uncertainties related to thermal runaway and free gas dispersion, so the test layout was designed to minimize these uncertainties. The test conditions applied to the SolaX ORI 5 MWh large-scale energy storage system presented a high level of challenge to both structural integrity and safety functions, and the results provide valuable engineering evidence for system-level energy storage safety.
Safety is not simply a compliance milestone for SolaX, because once a system is deployed, the associated risks are ultimately borne by the customer. Identifying potential issues early and clearly defining safety boundaries through rigorous testing is the company’s fundamental responsibility.
SolaX will continue to work closely with UL Solutions and other internationally recognized organizations to advance energy storage safety through system-level engineering validation, supporting the long-term, reliable integration of energy storage into global energy systems.
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