Korean data center fire heightens need for improved battery safety

A data center fire caused the shutdown of hundreds of online government services in South Korea, likely caused by a battery explosion. This incident is particularly severe, but there have been many like it through the battery energy storage system (BESS) industry, highlighting the need for further improvements to enhance battery safety.

At 8:20 pm on Friday 26th September, in Daejeon city, 85 miles from Seoul, a data center fire caused the shutdown of hundreds of online government services in South Korea. The cause of the fire is likely a battery explosion, which led to an out-of-control thermal runaway situation in a room with almost two hundred lithium-ion battery packs.

This incident is particularly severe, but there have been many similar incidents throughout the battery energy storage system (BESS) industry. Although the rate of battery fires per GWh deployed has decreased, the total number remains significant when summed over all battery deployments, due to the increasing number of deployments in data centers, electric vehicles, and other applications.

More stringent safety regulations have been implemented since 2020, but this incident highlights that further improvements are needed to enhance battery safety, as the deployment of Li-ion batteries continues to increase globally.

What is Li-ion battery thermal runaway?
Thermal runaway describes a situation in which exothermic reactions within the battery pack cause further exothermic reactions, causing the temperature to rise until extreme degradation and combustion of volatile gases and liquids become likely. It can spread from battery cell to battery cell in seconds, and from pack to pack in minutes.

In large-scale deployments with hundreds of packs and thousands of cells, as in the Daejeon city data center, the results of thermal runaway can be catastrophic; critically from a safety perspective but also from a financial perspective for the owner, not to mention the disruption to and security of services that data centers provide.

Battery fires in South Korea
According to the National Fire Agency, in the first half of 2025 there, have been 296 battery fire incidents in South Korea, leading to 23 casualties and 22.4 billion KRW in damages. This includes electric vehicle batteries, consumer electronics batteries, secondary batteries and primary batteries of varying chemistries. If that rate of incidents keeps up in 2025, this would be up from 2024, in which there were 543 incidents in total over the year, which in turn is up from 2023 when there were 359.

The rise in incidents is primarily driven by growth in battery deployments, e.g., in electric vehicles and stationary energy storage. One of the worst battery fire incidents in recent years in Korea occurred in a factory owned by Aricell, a producer of primary lithium batteries.

On June 24th 2024, in Hwaesong, 23 workers died in a blaze caused by a battery fault, of the hundred who were working in the factory at the time. Aricell received significant scrutiny after this event, which led to the resignation and charging of its CEO.

The circumstances around this fire indicate a lack of industry safety standards in place at the factory. This event shows the dangers of battery fires, and the negative perception that major incidents such as this can generate. Korea has had many problems with battery fires in the past -- a series of battery fires in 2018 led to significant stagnation in its BESS industry at that time, as well as product freezes, and indirectly resulted in the creation of the EPRI battery fire database, which monitors battery fire incidents in BESS around the world.

Regulation and rise of data centers
In the age of AI, and amid increasing reliance on cloud-based and internet-based services, data center power demands have risen. Data centers increasingly employ battery energy storage systems as a renewable power source. By combining BESS with renewable energy sources such as solar panels, green power can be supplied while still allowing for the peak stabilization that fossil-fueled grid sources would provide.

Data centers are one of the largest energy consumption sources in the world, requiring around 75GW of power consumption in total in 2025, a number expected to more than triple over the next ten years. This makes them a major target for increasing sustainability and reducing carbon footprint, as can be seen from IDTechEx's recent report: Sustainability for Data Centers 2025-2035.

With this comes the need to manage their power loads safely and reliably, to shave peak grid electricity to save on data center electricity consumption costs, as well as guarantee uninterruptible power supply (UPS). This can be achieved with cleaner energy technologies such as BESS, rather than diesel generators.

However, safety regulations surrounding BESS regarding thermal management and runaway prevention remain somewhat lacking, with fragmentary regulations from region to region.

Safety regulations
The US has the most stringent regulatory framework, specifically UL standards, however these are not binding on their own, but only for participating states applying NFPA codes. Europe requires a CE mark for new energy storage systems, but this does not count as a third-party testing, as it is self-declared, which means it cannot be used in the US.

China has improved regulations for battery packs in EVs, but has fallen behind in terms of BESS regulation. China recently passed the GB 38031-2025 regulation, which will go into effect in July 2026, and is the first 'no fire, no explosion' regulation in the world, i.e., requiring sufficient safety standards to be met that risk of fire is zero for EV battery packs.

This could have a knock-on effect for BESS battery packs, due to major battery suppliers (e.g., CATL, BYD), targeting both markets. However, as there is no single globally recognized safety standard for BESS safety, further regulations and development of a unified standard is needed to ensure battery safety in data centers can be achieved with a higher degree of confidence.

Solutions to improving battery storage safety for data centers
There are several avenues through which battery safety can be improved, each of which requires regulatory support to achieve wide-scale deployment and success:

Thermal management improvements: Employing active thermal management technologies, including liquid cooling systems and aerosol fire suppressants, and passive fire protection materials are key strategies for reducing the risk of battery fires and explosions, as is covered in IDTechEx's upcoming report: Thermal Management, Fire and Explosion Protection for BESS 2026-2036.

By effectively venting heat away from damaged cells, as well as integrating more thermally resistant pack, cell and enclosure designs (e.g. through use of thermally resistant materials such as ceramics, mica and insulating foams), thermal runaway can be prevented firstly from occurring and secondly from propagating between cells and packs.

This approach is also used wherever there are high power computing deployments, including server racks in data centers.

Improved diagnostics and monitoring: This also plays an important role in preventing battery fires. This includes both cell diagnostics and battery pack monitoring through sensors. Through use of AI-enhanced modelling and machine learning methods, battery module state of health (SoH) can be accurately tracked, which in turn allows for estimation of battery cell degradation, before faults can occur which might generate excess heat, and be the inciting event of a battery fire.

The integration of gas and pressure sensors, as well as moisture and humidity sensors, within the pack can also allow for much earlier warning of thermal runaway than is currently possible. During runaway, battery cells vent flammable gases into the battery pack enclosure. By detecting the buildup of these gases, thermal runaway events can be identified up to twenty-five minutes earlier, before battery fire occurs.

Alternative energy storage technologies: Another approach is to utilize an alternative energy storage technology. Lithium-ion batteries are ubiquitous across many industries due to high energy density, reasonable cycle life and reasonable power density, however for specific industries, alternatives exist.

For BESS, for example, redox flow batteries (RFBs) can instead be used in data center applications. While vanadium RFBs are typically more expensive, they do offer a longer cycle life and lower levelized cost of storage and most critically, non-flammable electrolyte. Redox flow batteries are primarily developed as a form of long-duration energy storage system, defined by IDTechEx as a system in which storage time exceeds six hours.

However, they could be used in data centers, with their non-flammable electrolyte acting as a key advantage, making them safer than Li-ion BESS. RFBs could be used to provide the key applications in a data center just how a Li-ion BESS would, including peak shaving, UPS, and managing volatile compute load applications.

As detailed in IDTechEx's upcoming report, Redox Flow Batteries 2026 - 2036, many players are developing RFB technologies, with Chinese player Rongke Power leading the way by capacity of global deployments. A similar solution is to use solid-state batteries which are also considered inherently safer, due to the lack of liquid electrolyte. Solid-state batteries are seeing initial rollout in China, though higher costs may prevent their usage in BESS.

Conclusions and outlook
Lithium-ion batteries are not an inherently safe technology, due to their flammable electrolyte. However, through proper management, improved diagnostics and potential advancements in design, or integration of alternatives, large-scale battery fires can be prevented. China's GB 38031-2025 regulation is a step in the right direction, but being limited to electric vehicles means that BESS regulations are falling behind.

IDTechEx's position is that only with effective, globally adopted, safety standards can the identified solutions be practically applied to prevent catastrophes such as in Daejon City. More transparency is also needed on the root cause of thermal runaway issues, which could be enabled through use of AI-driven diagnostics and advanced sensors.

However, BESS developers may not have interest in releasing root causes publicly, due to an inherent conflict of interest -- if the root cause is revealed to be due to product fault or component failure from a third-party supplier, it could lead to negative business consequences.

In the meantime, BESS developers will continue to strive for holistic approaches to BESS thermal management and fire and explosion protection, from active cooling and fire suppression systems to passive fire protection and fire-retardant materials. 

-- Daniel Parr, Technology Analyst, and Conrad Nichols, Senior Technology Analyst, IDTechEx, USA.