Pluggable Module Liquid Cooling With Compliant Thermal Interface

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Solution Overview

Problem

Liquid cooling of pluggable modules is challenging due to the need for removable connections that are costly, prone to leakage, and difficult to establish a good thermal interface without damaging thermal interface materials or requiring excessive insertion forces.

Innovation Solution

A pluggable module cooling assembly with a cooling interface block, a heat transfer device, and a cooling interface module that uses a compliant thermal gap pad and protective cover to establish a robust thermal interface without high contact pressures or damage, allowing for easy insertion and removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If liquid cooling is implemented for pluggable modules using removable connections, then cooling effectiveness is improved, but the system becomes costly and prone to leakage

Engineering Contradiction:
Improvecooling effectivenessVSAvoidleakage risk
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent introduces a thermal interface material (TIM) as an intermediary between the cold plate and the pluggable module. This TIM layer acts as a mediator that accommodates the removable connection while maintaining thermal contact, preventing direct liquid-coolant leakage paths while preserving cooling effectiveness through controlled thermal conduction.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cooling system is segmented into distinct components: a cold plate portion and a thermal interface material portion. This segmentation allows the cold plate to maintain structural integrity for liquid cooling while the TIM provides the flexible, removable interface, separating the liquid containment function from the thermal transfer function to reduce leakage risks.

Inventive Principle:
Principle #1Segmentation

2Temperature

If high contact pressures are used to establish thermal interface, then heat transfer rates are improved, but thermal interface materials are damaged

Engineering Contradiction:
Improveheat transfer rateVSAvoidTIM integrity
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent modifies the pressure parameter by using compliant, elastomeric thermal interface materials that can deform under low contact pressures to achieve adequate thermal contact. This parameter change allows sufficient heat transfer rates to be achieved without applying the high pressures that would damage traditional TIMs, maintaining both thermal performance and material integrity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs flexible, elastomeric thermal interface materials that can conform to surface irregularities under minimal pressure. This flexibility allows the TIM to maintain effective thermal contact without requiring high contact pressures, thereby preventing damage to the thermal interface material while achieving adequate heat transfer rates.

Inventive Principle:
Principle #30Flexible shells and thin films

3Temperature

If excessive insertion forces are applied, then thermal interface is established, but the module and cooling system are damaged

Engineering Contradiction:
Improvethermal interface qualityVSAvoidcomponent integrity
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The elastomeric thermal interface material acts as a compliant layer that deforms easily during insertion, allowing the module to be installed with minimal insertion force. This flexibility enables the thermal interface to be established without applying excessive forces that would damage the pluggable module or the cooling system components.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The compliant thermal interface material serves as a cushioning element that absorbs insertion forces before they can transmit to and damage the underlying components. This beforehand cushioning protects both the pluggable module and the cooling system from damage while still allowing adequate thermal contact to be established during normal insertion operations.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Ease of operation

If pluggable modules are made removable for easy installation, then ease of operation is improved, but establishing reliable thermal connections becomes difficult

Engineering Contradiction:
Improvemodule installabilityVSAvoidthermal connection reliability
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The elastomeric thermal interface material provides a flexible, compliant interface that maintains reliable thermal contact despite the removable nature of the pluggable module. This flexibility allows the module to be easily installed and removed while the TIM ensures consistent thermal connection reliability across multiple insertion cycles.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent uses a composite structure combining a rigid cold plate with a compliant elastomeric thermal interface material. This composite material approach allows the system to provide both the structural stability needed for reliable thermal connection and the compliance needed for easy module installation and removal.

Inventive Principle:
Principle #40Composite 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

Achieves effective heat transfer rates with minimal insertion forces and prevents damage to thermal interface materials, making liquid cooling of pluggable modules feasible and efficient.

Implementation Method 1

a cooling interface module disposed between the pluggable module and the cooling interface block and thermally coupling the pluggable module and the cooling interface block when the pluggable module is installed in the bay

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4687005A1Liquid cooling for pluggable modules
Publication Date: 2026.02.04 HEWLETT PACKARD ENTERPRISE DEV LP
  • EP4687005A1 patent drawingFigure 1
  • EP4687005A1 patent drawingFigure 2
  • EP4687005A1 patent drawingFigure 3

AI summary

An information processing system comprises a chassis defining a bay, a system board supported by the chassis, and a local liquid cooling subsystem supported by the chassis. The local liquid cooling subsystem is configured to circulate liquid coolant through the information processing system and comprises a cooling interface block thermally coupled to the liquid coolant. The cooling interface block comprising a slot. The system also comprises a pluggable module removably received in the bay. The pluggable module comprises a heat transfer assembly comprising a tab. The tab is removably received in the slot of the cooling interface block. The system also comprises a cooling interface module disposed in the slot between the tab and walls of the slot. The cooling interface module comprising a gap pad and a thermally conductive protective cover attached to the gap pad. The cooling interface module thermally couples the tab to the cooling interface block.