Modular Thermal Energy Storage Cards for Electronics Cooling

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Solution Overview

Problem

Phase change materials (PCMs) used for thermal management in electronic systems, such as avionics, face limitations due to their low thermal conductivity, which hinders effective heat conduction and dissipation, leading to increased thermal resistance and potential system failure during power spikes or loss of cooling.

Innovation Solution

A modular thermal energy storage system comprising stacked thermally conductive cards with phase change materials and enhanced interfaces, including heat pipes and vapor chambers, to reduce thermal resistance and increase thermal capacitance, allowing for efficient heat transfer and storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If phase change materials are used for thermal energy storage, then thermal capacitance is increased, but thermal conductivity is low resulting in high thermal resistance

Engineering Contradiction:
Improvethermal capacitanceVSAvoidthermal resistance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent uses composite materials by combining phase change material with thermally conductive additive particles. This creates a composite where the PCM provides high thermal capacitance through phase change while the conductive particles form a network that enhances thermal conductivity and reduces thermal resistance, resolving the contradiction between these two thermal properties

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating regions of high thermal conductivity within the PCM through the distributed conductive particle network. The conductive particles are strategically positioned to create thermal pathways, ensuring that heat can be efficiently transferred to and from the PCM without requiring the entire material to have uniformly high conductivity

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If large heat sinks are used to achieve stable thermal response, then thermal mass is increased, but system complexity and size increase

Engineering Contradiction:
Improvethermal response stabilityVSAvoidheat sink size
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent exploits phase transitions of the phase change material to achieve stable thermal response. During phase change, the material absorbs or releases latent heat at a constant temperature, providing inherent thermal stability without requiring large heat sink mass. This phase transition mechanism naturally stabilizes temperature fluctuations while maintaining a compact form factor

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The patent changes the thermal parameters of the system by using materials with high latent heat of fusion. This allows the system to achieve stable thermal response through the phase change temperature and latent heat properties rather than relying on large thermal mass, thereby reducing the size and complexity of the thermal management device

Inventive Principle:
Principle #35Parameter changes

3Reliability

If thermal conductivity additives are used to increase PCM conductivity, then thermal resistance is reduced, but material purity and phase change properties may be compromised

Engineering Contradiction:
Improvethermal conductivityVSAvoidmaterial composition control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent uses a porous structure approach where thermally conductive particles are distributed within the PCM matrix. The porous network formed by the conductive particles provides thermal pathways while maintaining the PCM's phase change properties. This structure allows heat transfer enhancement without requiring high concentrations of additives that would compromise material purity or phase change behavior

Inventive Principle:
Principle #31Porous materials

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 achieves low thermal resistance and high thermal capacitance, enabling effective heat management and extended operational time for electronic systems by efficiently storing and dissipating heat, even in the absence of cooling air, thus enhancing system reliability and performance.

Implementation Method 1

a phase change material having a melting point, the phase change material disposed within the plurality of cells and in thermal communication with cell walls of the plurality of cells

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

PCMs employ a change in phase of a substance from solid to liquid or liquid to gaseous to absorb the heat. By using this latent heat absorption, PCMs are significantly more effective in theory at absorbing heat from electronics

Methodology Applied
Scientific EffectLatent heat absorption: Latent Heat

Implementation Method 3

a thermally conductive interface disposed between the thermally conductive enclosure and the chassis, the thermally conductive interface extending from the interior cavity a distance beyond the interior cavity of the enclosure and in contact with the chassis

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

a thermally conductive enclosure bounding an interior cavity; a cell wall structure comprising a plurality of cells disposed within the interior cavity and in thermal communication with the thermally conductive enclosure

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3240386B1Thermal capacitance system
Publication Date: 2020.05.27 GENERAL ELECTRIC CO
  • EP3240386B1 patent drawingFigure 1A
  • EP3240386B1 patent drawingFigure 1B~1C
  • EP3240386B1 patent drawingFigure 2~3

AI summary

A system for cooling electronics includes at least two modular thermal energy storage cards stacked in one of a horizontal or a vertical stack, where the stack provides cooling to a portion to electronics. The cards include: a thermally conductive enclosure bounding an interior cavity, a cell wall structure that includes cells disposed within the interior cavity and in thermal communication with the thermally conductive enclosure, a phase change material having a melting point where the phase change material disposed within the cells and in thermal communication with cell walls of the cells, and a thermally conductive interface disposed between the thermally conductive enclosure and a portion of the electronics that includes a heat generating surface. The thermally conductive interface extends from the interior cavity a distance beyond the interior cavity of the enclosure and is in contact with the heat generating surface.