[HeavyChemON] 'Sprinkler' Inside Batteries... Samsung SDI Directly Cools Thermal Runaway Cells

Direct Supply of Cooling Water and Fire Suppressant to Runaway Cells
Blocking the Chain Reaction of Heat Propagation to Adjacent Cells
Strengthening Safety Technology as ESS and AI Data Centers Expand

If a thermal runaway occurs in a battery cell, causing hot gas to be released, the cooling water pipe located directly above bursts. The spilled coolant subsequently cools both the problematic cell and its surrounding cells. In effect, it’s as if a ‘sprinkler’ system has been installed inside the battery.

Samsung SDI is accelerating the development of safety technology that directly cools cells experiencing thermal runaway, thereby preventing the spread of fires. As the markets for batteries used in energy storage systems (ESS) and artificial intelligence (AI) data centers rapidly expand beyond electric vehicles, the speed at which a fire can be contained is emerging as a new source of competitive edge.

Prismatic batteries used in automobiles. Samsung SDI

According to U.S. patent documents released on August 29, two patents related to battery fire safety filed by Samsung SDI were published in the United States on August 27. The publication numbers are US20260253992 and US20260254077.

The first patent, titled 'Battery System and Vehicle Including the Battery System,' utilizes the high-temperature gases produced during thermal runaway to activate the cooling system.

Battery cells are equipped with gas vents that expel their hot, high-pressure gases outside during thermal runaway. Samsung SDI has arranged pipes carrying coolant along the gas vents of multiple cells.

When thermal runaway occurs in a specific cell, the high-temperature gas expelled from the vent ruptures the pipe and causes the liquid inside to be released around that cell. In particular, the section of the pipe facing the gas vent is designed to be thinner than other portions so that it will burst first in the event of a problem above the affected cell. The system also incorporates the structure of utilizing standard coolant, which normally serves to lower the battery temperature.

The released liquid seeps in between the cells. The buffer material installed between the cells absorbs the liquid, cooling both the runaway cell and adjacent cells. The key is to prevent or delay the spread of heat from a single cell to its neighbors.

The 'Battery Module' patent, also published on the same day, takes a different approach by creating a dedicated firefighting fluid channel.

Channels for firefighting fluid are installed inside the structures that fix the electrical connectors of multiple battery cells, with individual openings directed toward each cell. If an abnormality occurs in a particular cell, firefighting fluid is supplied intensively to that cell and its surroundings. Not only water, but also heat-absorbing or oxygen-blocking suppressant materials can be used.

Samsung SDI has conducted thermal propagation tests in actual battery modules by inducing thermal runaway in specific cells and then injecting suppressant fluid to measure temperature changes in adjacent cells.

Although the two technologies operate differently, their goal is the same: to directly target the cell where thermal runaway starts, and to immediately interrupt the chain reaction of heat spreading from the affected cell to neighboring cells and the entire module.

ESS and AI Data Center Expansion Makes Safety a 'Key to Winning Orders'

Battery for UPS. Samsung SDI

The reason behind Samsung SDI strengthening its fire safety technology lies in the changing battery market landscape. As the growth of the electric vehicle sector slows, energy storage systems (ESS), as well as uninterruptible power supplies (UPS) and battery backup units (BBU) for AI data centers, are emerging as new sources of demand.

Samsung SDI is actively expanding its presence in these markets. On August 11, the company secured its first independent production base in North America by acquiring the 49.99% stake in a joint venture battery plant in New Carlisle, Indiana, previously held by General Motors (GM). This plant will be used to produce batteries tailored for ESS applications to meet market demand.

The battery business for AI data centers is also growing. Samsung SDI is supplying high-power UPS batteries, and in the second quarter of this year, increased sales of products related to AI data centers—such as UPS, BBU, and ESS for power—contributed to improved financial performance. The company plans to further expand its UPS production capacity in the second half of the year.

Since both ESS installations and data centers require a large number of battery cells and modules in a single area, the ability to prevent the spread of fire is especially critical. If thermal runaway in one cell spreads to neighboring cells, modules, or storage units, the scale of damage can increase rapidly.

In July, Samsung SDI also demonstrated the effectiveness of its fire spread prevention technology during a large-scale fire test of UPS batteries conducted by global safety certification organization UL Solutions. During the test, where battery modules were deliberately put into thermal runaway, the fire did not spread to adjacent battery storage units and was extinguished even without the building’s overhead sprinkler system operating.

Samsung SDI has already applied heat insulation and suppression systems for fire spread prevention to its existing products. Now, with the addition of automatic coolant release during thermal runaway and the direct injection of suppressant fluid into abnormal cells, the company is layering its safety technology further.

As the battery market broadens from electric vehicles to ESS and AI data centers, the criteria for competition are changing. Beyond energy density, output, and price, the ability to promptly contain thermal runaway in a single cell and prevent its spread is now emerging as a new competitive factor that determines success in battery contracts.

This content was produced with the assistance of AI translation services.