Fire Prevention · Thermal Management
What is Immersion Cooling For Battery Energy Storage?
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The New Standard in
Fire Prevention and
Thermal Management for
Lithium-Ion Battery Energy Storage
Immersion cooling submerges lithium-ion battery cells in a dielectric, non-toxic, biodegradable fluid with a high fire point. The fluid remains in constant contact with every cell surface, drawing heat away and keeping cells operating at consistent, ideal temperatures.
Submerging the cells also isolates them from oxygen and from one another. In the event of thermal runaway, cells cannot ignite or propagate heat to adjacent cells.
It is the only solution that prevents lithium-ion battery fires before they start.
The Evolution of Cooling
THE FIRST STANDARD
Air
Simple, low cost, but limited heat transfer
THE PREVIOUS STANDARD
Liquid Cold Plate
Improved heat removal but creates hot & cold spots with only one contact surface
THE NEXT GENERATION
Immersion
Tighter temperature delta minimizes thermal gradients, reducing degradation, extends battery life, and avoids stranded energy
Why is Thermal Management Important?
Excessive heat drives battery cell degradation and thermal runaway: The two biggest performance and safety challenges in lithium-ion battery energy storage
Immersion Cooling Benefits
Maintains Cell Temperature
Fluid surrounds each cell to remove heat evenly and maintain stable operating temperatures.
Limits Thermal Runaway
Quickly removes heat to reduce the likelihood of dangerous temperature escalation inside the cell.
Prevents Propagation
Isolates cells to stop heat and fire from spreading from one cell to the next.
Slows Battery Degradation
Consistent cell temperatures reduce thermal stress, slowing capacity loss and performance decline.
Extends Battery Life
Lower cell stress increases cycle life and reduces long-term replacement frequency.
Reduces OpEx
Improves cooling efficiency, lowers maintenance requirements, and reduces total operating costs.
How It Works:
LiquidShield Immersion Technology
Complete Cell Immersion
Each lithium-ion cell is fully submerged in dielectric fluid, placing the cooling medium in direct contact with every cell surface.
This removes heat immediately and evenly, eliminating hotspots and temperature gradients that accelerate degradation and increase thermal runaway risk.
The fluid also creates a protective barrier around every cell. By isolating cells from oxygen and from one another, immersion cooling prevents flames and contains any cell-level failure rather than allowing heat or fire to propagate through the module.
Each module uses our patented dual-wall liner that provides redundant protection against fluid leakage while also supporting controlled internal flow paths. In the pump fails, the cells stay fully submerged, with leak detection adding another layer of system-level protection.
Active Circulation & Heat Exchanger
The Battery Management System continuously monitors temperatures and circulates the immersion fluid to maintain thermal balance across the battery array.
As the fluid absorbs heat, it is routed through an integrated heat exchanger, where that heat is transferred to a water/glycol loop and carried to an external chiller.
This closed-loop process keeps cells operating at stable, ideal temperatures under real-world charge and discharge conditions. The result is safer operation, slower degradation, and longer battery life.
Immersion Cooling Fluid
Shell BESS Fluid S5 MIVOLT is a synthetic ester dielectric fluid engineered for immersion-cooled battery storage. Its combination of electrical insulation, high fire-point performance, thermal stability, and biodegradability supports safer operation, efficient heat removal, and long-term reliability.
In Partnership with Shell BESS Fluids
Non-Conductive
The fluid safely surrounds energized battery cells while enabling direct-contact cooling without electrical shorting.
High Fire Point
With a flash point above 250°C and fire point above 310°C, the fluid delays ignition and resists combustion.
Thermally Stable
Synthetic ester chemistry retains thermal performance under elevated temperatures, supporting long-term cooling reliability.
Readily Biodegradable
The fluid is readily biodegradable and not classified as a physical, health, or environmental hazard under GHS criteria.
Optimized Heat Removal
Its thermophysical properties support direct, continuous heat transfer and stable temperatures across the module.
Flow Efficient
Low viscosity supports efficient circulation while maintaining safety and performance advantages.
Immersion Cooling FAQ
What Is Thermal Runaway and What Causes It in Lithium-Ion Batteries?
Thermal runaway is a self-accelerating failure event in which a battery cell generates heat faster than it can dissipate it, causing temperature to rise rapidly and potentially leading to fire. It can be triggered by overheating, short circuits, overcharging, mechanical damage, or internal cell defects.
Why Is Immersion Cooling More Effective Than Air or Cold Plate Cooling?
Immersion cooling places dielectric fluid in direct contact with every cell surface, removing heat faster and more evenly than air or indirect cold plate methods. That direct-contact cooling reduces hotspots, lowers temperature variation across the pack, and improves overall thermal performance.
How Does EticaAG’s Immersion Cooling System Work?
EticaAG fully submerges each battery cell in dielectric fluid so heat is drawn directly from all cell surfaces. The Battery Management System then circulates the fluid in response to rising temperatures to maintain real-time thermal balance across the array.
How Is Fluid Circulation Controlled in EticaAG’s Immersion Cooling System?
Fluid circulation is controlled by the Battery Management System, which monitors temperatures and activates circulation as needed to dissipate heat. This keeps cells within a stable operating range under charge, discharge, and peak load conditions.
How Does EticaAG’s Immersion Cooling System Prevent Fire Propagation?
The dielectric fluid removes heat, isolates cells from one another, and limits the ignition conditions needed for fire to spread. In EticaAG’s UL 9540A-related testing, propagation could not be achieved with immersion cooling active.
How Does Immersion Cooling Reduce Battery Degradation and Extend Battery Life?
Stable, uniform cell temperatures slow the thermal stress that drives capacity fade, mismatch, and degradation knees. In EticaAG testing, immersion cooling extended battery life by 20% compared with cold plate cooling.
How Do You Prevent Fluid Leaks in an Immersion-Cooled Battery System?
EticaAG’s patented dual-wall containment liner is designed to contain a potential fluid leak at the module level while maintaining full cell submersion, even if circulation stops or power is lost. Each module retains the minimum fluid required to keep cells protected. External circulation lines use shut-off connectors that seal when disconnected, while containment pans in the enclosure floor provide an added layer of spill protection. Integrated leak detectors trigger a BMS alert, notifying maintenance teams and enabling a system shutdown if needed.
What Makes Shell BESS Fluid S5 MIVOLT Well Suited for Immersion Cooling?
Shell BESS Fluid S5 MIVOLT is a synthetic ester dielectric fluid with a high fire point, strong thermal stability, low viscosity for efficient circulation, and a non-hazardous GHS classification. Its properties support direct-contact cooling, long-term reliability, and strong fire-safety performance in immersion-cooled BESS.