Flexible Graphite Thermal Cable for Server Cooling

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Solution Overview

Problem

Traditional cooling methods for information handling system components, such as servers, face challenges with rigid liquid cooling systems that require large tubes and difficult thermal coupling, leading to increased installation time and decreased component density, as well as stress on memory modules during installation.

Innovation Solution

A flexible graphite thermal cable is used, rolled into a cylindrical shape and covered with a thermally-insulating layer, with terminations for thermal coupling to both the thermal source and sink, providing a flexible and efficient heat-rejecting medium that minimizes thermal resistance and enhances serviceability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rigid liquid cooling systems are used, then heat transfer efficiency is improved, but device complexity and installation difficulty increase

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidcooling system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces rigid liquid cooling tubes with flexible graphite thermal cables that can be easily routed and installed. The flexible nature of the thermal cable eliminates the need for large-diameter tubes and complex routing, while maintaining effective thermal coupling between components and heat sinks.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent substitutes the mechanical liquid cooling system with a solid-phase thermal conduction system using graphite material. This eliminates the need for liquid flow mechanisms, pumps, and large-diameter tubes, while achieving comparable or superior thermal transfer efficiency through the high thermal conductivity of graphite.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If rigid copper components are used for thermal coupling, then thermal conductivity is improved, but ease of operation and installation are worsened

Engineering Contradiction:

Improvethermal conductivityVSAvoidinstallation ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent uses flexible graphite thermal cables that can be easily bent, routed, and installed around various components without requiring rigid mounting structures. The flexibility allows for simple hand installation while the graphite material provides thermal conductivity comparable to or exceeding traditional copper components.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the physical state from rigid copper to flexible graphite, maintaining high thermal conductivity while dramatically improving flexibility and ease of installation. The graphite material's inherent properties provide both the required thermal performance and mechanical flexibility.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If liquid cooling tubes are routed through memory components, then cooling effectiveness is improved, but manufacturing precision and component density are worsened

Engineering Contradiction:

Improvecooling effectivenessVSAvoidmemory module pitch

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent uses thin, flexible graphite thermal cables that can be installed without increasing memory module pitch or requiring precise routing through memory components. The cables can be easily positioned and attached without stressing memory modules or requiring specialized installation jigs.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent extracts the cooling function from the memory module structure itself, using separate flexible thermal cables that attach to components without requiring internal routing through the memory modules. This eliminates the need for increased pitch and complex integration.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If traditional cooling systems are used, then heat rejection is achieved, but loss of time for component replacement increases

Engineering Contradiction:

Improveheat rejection capabilityVSAvoidcomponent replacement time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The flexible graphite thermal cables can be quickly removed and reinstalled on replaced components, dramatically reducing processor changeover time from 30-60 minutes to a much shorter duration. The cables' flexibility allows for easy detachment and reattachment without complex disassembly.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a dynamic, easily reconfigurable cooling system where thermal cables can be quickly attached and detached as components are replaced. This dynamic capability enables rapid maintenance and component swapping while maintaining continuous cooling functionality.

Inventive Principle:

Principle #15Dynamics

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 flexible graphite thermal cable effectively transfers heat between components, reducing the need for large, rigid cooling systems and simplifying installation, thereby improving cooling efficiency and reducing component stress, while maintaining a high thermal conductivity comparable to copper.

Implementation Method 1

a first termination at which the flexible graphite layer thermally couples to the thermal source, and a second termination at which the flexible graphite layer thermally couples to the thermal sink

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

covered on the outside thereof by a thermally-insulating layer of the same cylindrical shape

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS11248852B2Graphite thermal cable and method for implementing same

Publication Date: 2022.02.15 DELL PROD LP

AI summary

A system may include a thermal source, a thermal sink and heat-rejecting media comprising a thermal cable, the thermal cable comprising a main length comprising a flexible graphite layer rolled into a cylindrical shape covered on the outside thereof by a thermally-insulating layer of the same cylindrical shape, a first termination at which the flexible graphite layer thermally couples to the thermal source, and a second termination at which the flexible graphite layer thermally couples to the thermal sink.