Passive Battery Cooling via Coolant Pool and Burst Disk

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Solution Overview

Problem

High-energy battery chemistries, such as lithium cobalt oxide, are prone to thermal runaway due to operating temperatures exceeding thermal breakdown limits, leading to potential power failure or fire, and external active cooling is not feasible during emergency operations.

Innovation Solution

A passive battery cooling system with internal sensors, dividers, and a sealed housing containing a thermally conductive cooling fluid for natural convection and pressure relief through a burst disk to vent gases and maintain safe temperatures, while allowing for continued operation during emergencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If high-energy battery chemistries are used to improve power density, then volume and weight are reduced, but thermal stability deteriorates leading to thermal runaway risk

Engineering Contradiction:
Improvebattery weightVSAvoidthermal stability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

A coolant pool is introduced as an intermediary substance between the battery cells and the external environment. The coolant pool absorbs excess heat from the battery cells through natural convection, preventing thermal runaway while allowing the use of high-energy chemistries. The coolant acts as a thermal buffer that mediates between the battery's heat generation and the external cooling requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cooling system utilizes natural convection currents within the coolant pool to automatically circulate and distribute heat without requiring external pumps or active control systems. The heated coolant naturally rises and cooler coolant sinks, creating a self-sustaining circulation pattern that provides continuous passive cooling.

Inventive Principle:
Principle #25Self-service

2Reliability

If external active cooling systems are implemented to control battery temperature, then thermal stability is improved, but device complexity and power consumption increase

Engineering Contradiction:
Improvetemperature controlVSAvoidcooling system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cooling system eliminates complex active components by utilizing natural convection currents within the coolant pool. The heated coolant naturally rises and cooler coolant sinks, creating a self-sustaining circulation pattern that provides continuous passive cooling without requiring pumps, valves, or external power sources.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical active cooling systems (pumps, fans, valves) with a passive thermal management approach based on natural convection and phase change. This substitution eliminates the need for complex mechanical components while maintaining effective temperature control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If cooling systems are operated continuously to maintain battery temperature, then thermal stability is improved, but power consumption increases during emergency operations

Engineering Contradiction:
Improvetemperature controlVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The cooling system requires no external power input as it operates entirely on natural convection principles. The temperature-driven density differences in the coolant automatically generate circulation currents that provide continuous cooling without consuming electrical power, making it ideal for emergency operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The coolant utilizes phase change (evaporation and condensation) as part of its cooling mechanism. When the coolant reaches its boiling point, it undergoes phase transition, absorbing large amounts of latent heat from the battery cells. This phase change process provides intensive cooling during critical periods without requiring additional power input.

Inventive Principle:
Principle #36Phase transitions

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

The system effectively controls battery temperatures, prevents overheating, and ensures safe venting of gases, enhancing battery safety and reliability, even during emergency power operations.

Implementation Method 1

a sealed housing containing a thermally conductive cooling fluid for natural convection

Methodology Applied
Scientific EffectNatural convection: Free Convection

Implementation Method 2

a sealed housing containing a thermally conductive cooling fluid

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

pressure relief through a burst disk to vent gases

Methodology Applied
Scientific EffectPressure relief: Depressurisation

Data Source

PatentEP2806494B1Thermal management electrical storage devices by coolant pool
Publication Date: 2018.11.14 HAMILTON SUNDSTRAND CORP
  • EP2806494B1 patent drawingFigure 1~2
  • EP2806494B1 patent drawingFigure 3~5

AI summary

A battery system (70) includes a passive cooling system for cooling a plurality battery cells (12) during normal operation and during overheating of the battery cells. The passive cooling system includes a housing (16), a cooling fluid (coolant pool) (14) within the housing (16), and a plurality of dividers (18) between each of the plurality of battery cells (12).