From Server Racks to Battery Racks: Why Immersion Cooling Is the Future of Safe Energy Storage in Data Centers

Immersion cooling—the technique of submerging hardware in dielectric fluids—has become standard practice in high-performance computing environments with high thermal loads. It is efficient, scalable, and supports energy efficiency gains in high-density server configurations.

Simultaneously, to ensure uptime and energy resilience, data centers are increasingly deploying Battery Energy Storage Systems (BESS) and Uninterruptible Power Supplies (UPS). However, these systems introduce new thermal management and safety challenges that are often under-discussed.

This paper explores how immersion cooling technology, already validated in IT infrastructure, can be adapted to enhance the safety and performance of lithium-ion battery energy storage systems.

Immersion Cooling in IT: The Key to Performance Excellence

In IT infrastructure, immersion cooling is employed to manage the high thermal loads generated by CPUs and GPUs. This method typically involves single-phase or two-phase systems. In single-phase immersion cooling, hardware is submerged in a non-conductive liquid that absorbs heat and then circulates through a heat exchanger to dissipate it.

Its primary performance characteristics include:

• Exceptionally high thermal transfer efficiency: The thermal conductivity of the fluid used is typically 10-20 times that of air.
• Energy efficiency: The system achieves a Power Usage Effectiveness (PUE) as low as 1.05.
• Higher hardware density: Supports deploying server racks exceeding 100 kilowatts without requiring throttling.

These capabilities directly address the limitations of air cooling in high-density applications. Similar thermal stress characteristics observed in energy storage battery systems indicate this approach can be scaled beyond CPU applications.

Why lithium-ion battery racks pose a fire hazard
Lithium-ion batteries used in BESS and UPS systems exhibit thermal sensitivity. Chemical formulations such as NMC (nickel manganese cobalt), LFP (lithium iron phosphate), and NCA (nickel cobalt aluminum) offer high energy density but are prone to thermal runaway—a self-sustaining failure mechanism that can lead to combustion.

Thermal runaway may initiate at temperatures as low as 150°C and result in:

• Battery cell rapidly heats up
• Electrolyte decomposes and releases gas
• Failure propagates to adjacent battery cells

Real-world cases demonstrate that standard HVAC systems are incapable of containing such incidents. For instance, the 2022 fire at SK Group's data center in South Korea and the 2019 explosion at the McMicken battery energy storage system in Arizona, USA, both underscore the necessity of implementing proactive thermal containment strategies.

Energy Storage Immersion Cooling: A Safer, Smarter Evolution
In the energy storage sector, immersion cooling involves submerging battery cells in a dielectric fluid with a high flash point and chemical stability. This system operates by directly dissipating heat from each battery cell while acting as a barrier to oxygen—a necessary component for combustion.

Beyond the scope of backup power applications
The role of modern BESS solutions extends beyond backup power. They enhance power quality, increase uptime, and reduce operational costs.

Power Quality Regulation: During voltage sags or surges, the BESS can inject or absorb power within milliseconds to stabilize voltage. It also regulates frequency in both grid-connected and islanded modes. Additionally, it filters harmonics and smooths transient fluctuations, thereby improving power quality and reducing stress on IT equipment.

Extended Backup Power (as UPS Partner): The system responds instantly to outages and sustains power for hours. This addresses longer-duration failures, reduces reliance on generators, and lowers emissions. A portion of battery capacity can be reserved for emergencies, while the remainder serves economic functions.

Peak Shaving and Load Management: During high-demand periods, BESS discharges to reduce power draw from the grid. This reduces demand charges and flattens load curves. It also delays infrastructure upgrades and enables energy arbitrage—charging during off-peak hours and discharging during peak periods.

By integrating these capabilities, immersion-cooled BESS transforms from a passive backup tool into a dynamic asset that enhances reliability and efficiency.

Deployment Considerations for Data Centers

When considering deployment of immersion-cooled BESS, operators should evaluate the following factors:

System footprint: Modular designs compatible with standard rack configurations can be adopted.

Monitoring system: Must integrate with battery management and facility monitoring platforms.

Standard compliance: Systems should meet standards such as UL 9540, UL 1973, and NFPA 855.

Maintenance: Coolant remains stable long-term without frequent replacement.

Financially, immersion cooling may involve higher initial costs, but calculations indicate an average payback period typically under eight years due to operational savings and extended equipment lifespan.

Elevating battery safety to server-grade standards

As data centers evolve, the technologies ensuring performance and safety must advance in tandem. Immersion cooling has proven effective in server environments, offering a technically viable and safety-enhancing approach to managing thermal and fire risks associated with lithium-ion energy storage systems.

Adapting proven thermal management strategies from computing to energy systems points the way toward building safer, more efficient infrastructure. Facilities planning to expand BESS capacity or upgrade thermal control measures should consider immersion cooling as a reliable option grounded in existing best practices and emerging safety standards.

Born for Future Cooling: High-Performance KEY Fluorinated Liquid Solutions

The exceptional performance of immersion cooling technology hinges on one of its core foundations: an efficient, stable, and safe cooling medium.

We specialize in the research, development, and production of high-performance electronic fluorinated fluids specifically engineered to meet the stringent demands of cutting-edge immersion cooling applications—whether for IT servers or battery energy storage systems. Our products feature the following key characteristics, aligning perfectly with the technological advancements discussed in this article:

Ultimate Safety and Stability: Featuring exceptionally high dielectric strength, non-flammability (no flash point/ignition point), and outstanding chemical and thermal stability, it is the ideal choice for preventing thermal runaway propagation in lithium-ion batteries and ensuring the safe operation of sensitive electronic equipment.

Superior Thermal Management Performance: Low viscosity and high fluidity combined with excellent thermal conductivity enable rapid, uniform heat dissipation, significantly enhancing system cooling efficiency and energy efficiency.

Broad Material Compatibility: Compatible with common components including metals, plastics, and sealing materials, ensuring long-term reliable system operation.

Environmentally Sustainable: Product design balances performance with environmental responsibility, with select series featuring low Global Warming Potential (GWP).

We provide fluorinated liquid solutions—ranging from standard products to customized formulations—alongside professional technical support services for clients in data centers, high-performance computing, battery energy storage, power electronics, and related fields.

Let innovative coolants become your reliable partner for safety and energy efficiency upgrades.

Contact us to learn more about how our fluorinated liquid products can support your immersion cooling projects, helping us build efficient and safe future infrastructure together.

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