Battery Immersion Cooling with Pressure-Controlled Dielectric Boiling

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Solution Overview

Problem

Current air cooling systems for lithium-ion battery cells have limitations in heat transfer capacity, necessitating additional thermal barriers to prevent thermal runaway and associated safety issues.

Innovation Solution

The implementation of a battery immersion cooling system using a boiling liquid dielectric material with a boiling point under 75°C, which surrounds the battery cells and facilitates heat transfer through vaporization and condensation, along with a pressure control device to manage boiling point and pressure within the system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If air cooling systems are used to transfer heat away from battery cells, then the system structure is simple, but the heat transfer capacity is limited

Engineering Contradiction:

Improvecooling system structureVSAvoidheat transfer capacity

Core Design Contradiction:

Device complexityVSTemperature

Solution Approach 1:

The patent utilizes the phase transition of dielectric fluid from liquid to vapor (boiling) to absorb large quantities of heat from battery cells. The fluid boils at controlled temperatures (e.g., 70-90°C) creating vapor that rises to heat exchangers, providing high heat transfer capacity through latent heat absorption without requiring complex active cooling systems

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The invention employs hydraulic principles by immersing battery cells in dielectric fluid and using natural convection currents driven by density differences between hot vapor and cooler liquid. The system uses fluid circulation through heat exchangers to transfer heat, eliminating the need for complex pumps and active cooling mechanisms while maintaining high heat transfer efficiency

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Device complexity

If air cooling systems are used, then the system is simpler, but additional thermal barriers are needed to prevent thermal runaway propagation

Engineering Contradiction:

Improvecooling system structureVSAvoidthermal event propagation mitigation

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent uses electrically insulating dielectric fluids (such as fluorinated liquids or silicone oils) that create an inert environment around battery cells. These fluids have high dielectric strength that prevents electrical arcing and thermal runaway propagation between cells, eliminating the need for additional thermal barriers while improving safety

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The dielectric fluid acts as an intermediary medium between battery cells, absorbing excess heat through boiling and preventing direct thermal contact between cells. The fluid's high specific heat capacity and latent heat of vaporization allow it to absorb large amounts of thermal energy, preventing thermal runaway propagation without requiring physical barriers

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If a low boiling point dielectric material is used, then heat transfer capacity is enhanced through vaporization, but the boiling point must be precisely controlled under 75°C

Engineering Contradiction:

Improveheat transfer capacityVSAvoidboiling point control

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent selects dielectric fluids with specifically engineered boiling points (e.g., 70-90°C) that optimize heat transfer efficiency. By changing the boiling point parameter of the dielectric fluid, the system achieves high heat transfer capacity while maintaining safe operating temperatures for lithium-ion batteries, balancing thermal management effectiveness with cell safety

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enhances heat transfer capacity, mitigates thermal event propagation, and provides passive prevention of thermal runaway, ensuring safe and efficient operation of battery modules.

Implementation Method 1

the plurality of battery cells generating heat energy which is transferred to the liquid dielectric material thereby causing at least a portion of the liquid dielectric material to vaporize

Methodology Applied

Scientific EffectVaporization: Evaporation

Implementation Method 2

the one or more heat exchange devices configured to remove heat from the vaporized dielectric material thereby causing the dielectric material to condense and be returned to the liquid reservoir

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 3

a liquid dielectric material having a boiling point under standard atmospheric pressure of less than 75° C., wherein during operation, the plurality of battery cells generating heat energy which is transferred to the liquid dielectric material

Methodology Applied

Scientific EffectLatent heat of vaporization: Latent Heat

Data Source

PatentUS20250062443A1Battery immersion cooling with controllable dielectric boiling point and thermal runway passive protection

Publication Date: 2025.02.20 BLUE ORIGIN MANUFACTURING LLC

AI summary

The present invention relates to battery immersion cooling of battery cells through vaporization of a dielectric liquid, such as through nucleate boiling. The boiling point of the liquid can be adjusted through control of the pressure to which the dielectric liquid is exposed. The quantity of liquid dielectric material is selected to adsorb the complete reaction energy of the electrical parallel cells in case of thermal runaway, leading to no propagation, flame or explosion.