Liquid-Cooled Resistor With Elastic Pressing Mechanism

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Solution Overview

Problem

Existing liquid-cooled resistor devices face inefficiencies in heat transfer due to thermal contact resistance and low heat capacity, leading to bulky and heavy designs, particularly when used for high-energy dissipation applications like regenerative braking of inverter-driven electric motors.

Innovation Solution

The use of elastic pressing means with a thermally conductive, electrically insulating flat layer and a liquid flow path with turbulence-enhancing springs improves heat transfer between the resistor and the cooling liquid, increasing the device's efficiency and allowing for a compact, lightweight design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If rigid connection between blocks is used to hold the resistor, then the device structure is simple, but thermal contact resistance limits heat transfer efficiency

Engineering Contradiction:
Improvedevice structureVSAvoidheat transfer efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

A thermally conductive, electrically insulating flat layer is introduced as an intermediary between the resistor and the liquid-cooled block. This layer eliminates thermal contact resistance while maintaining electrical insulation, thereby improving heat transfer efficiency without complicating the overall device structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal contact resistance parameter is changed by introducing the flat layer with high thermal conductivity and electrical insulation properties. This parameter change enables efficient heat transfer while maintaining the simplicity of the rigid connection structure.

Inventive Principle:
Principle #35Parameter changes

2Weight of stationary object

If low heat capacity blocks are used, then the device is lighter, but the overall rate of heat dissipation is limited

Engineering Contradiction:
Improveblock weightVSAvoidheat dissipation rate
Core Design Contradiction:
Weight of stationary objectVSProductivity

Solution Approach 1:

The flat layer acts as a thermal bridge that enhances the effectiveness of the cooling liquid's heat capacity. By improving thermal contact between the resistor and cooling liquid, the system achieves high heat dissipation rates without requiring large-mass blocks.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention utilizes liquid cooling with optimized flow paths to enhance convective heat transfer. The cooling liquid's high heat capacity and flow dynamics compensate for the low heat capacity of lightweight blocks, maintaining high heat dissipation rates.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Loss of energy

If large resistors and liquid-cooled blocks are used for high energy dissipation, then the heat dissipation capacity is sufficient, but the device becomes bulky and heavy

Engineering Contradiction:
Improveenergy dissipation capacityVSAvoiddevice weight
Core Design Contradiction:
Loss of energyVSWeight of stationary object

Solution Approach 1:

The flat layer enables high energy dissipation capacity in a compact form by maximizing thermal contact efficiency. This allows the use of smaller, lighter components while maintaining the required heat dissipation performance for high-power applications.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The thermal contact resistance parameter is optimized to enable high energy dissipation in a compact volume. By changing the thermal interface properties through the flat layer, the system achieves high power density without increasing device weight or volume.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If thermal contact resistance is present at the interface, then the device structure is simple, but the heat transfer efficiency is reduced

Engineering Contradiction:
Improveinterface structureVSAvoidheat transfer efficacy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The flat layer serves as a thermal intermediary that eliminates interface thermal resistance. This simple addition significantly improves heat transfer efficacy and reliability without complicating the device structure, as the layer integrates seamlessly between existing components.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration enhances heat transfer by 200-300%, enabling a smaller, lighter, and more vibration-resistant device while maintaining safety and economic viability.

Implementation Method 1

a liquid flow path (6) between the inlet (4) and the outlet (5)

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

a thermally conductive, electrically insulating flat layer (7)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2592633B1Liquid-cooled resistor device
Publication Date: 2017.06.14 CRESSALL RESISTORS
  • EP2592633B1 patent drawingFigure 1

AI summary

Liquid-cooled resistor device (1) comprising a block (3) having a liquid inlet (4), a liquid outlet (5) and a cavity provided with a liquid flow path (6) between the liquid inlet (4) and the liquid outlet (5), the cavity having an open side closed by a thermally conductive, electrically insulating flat layer (7) supporting a flat resistor (2) with their main planes parallel to one another, the device further comprising an electrically insulating blocking plate, rigidly fastenable to the block (3), facing the resistor (2) to block the resistor (2) on the flat layer (7), the cavity housing elastic pressing means configured so as to force the flat layer (7) against the resistor (2).