Flexible PCB Thermal Management for Motor Cooling

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Solution Overview

Problem

Conventional heat sinks and cooling structures are inadequate for managing high heat flux in electronic assemblies, particularly in industrial power conversion applications, leading to thermal management challenges and increased packaging size due to additional bonding layers and thermal resistance.

Innovation Solution

A thermal management assembly using a flexible substrate with a cooling jacket and thermal compensation base layer, integrated with a motor, which includes a jacket manifold for fluid flow to effectively remove heat from switching semiconductor devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional heat sinks are used to cool electronic assemblies, then heat removal capability is provided, but packaging size increases due to additional bonding layers and thermal matching materials

Engineering Contradiction:

Improveoperating temperatureVSAvoidpackaging size

Core Design Contradiction:

TemperatureVSVolume of stationary object

Solution Approach 1:

The cooling structure is merged with the PCB substrate by integrating the cooling channels directly into the PCB layers. This eliminates the need for separate heat sinks and thermal matching materials, thereby reducing packaging size while maintaining heat removal capability. The cooling fluid channels are formed within the PCB itself, creating an integrated thermal management solution.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention transitions from conventional three-dimensional heat sink structures to a planar two-dimensional cooling approach by embedding cooling channels within the PCB layers. This dimensional change allows heat dissipation to occur within the plane of the PCB rather than requiring additional vertical space, thus reducing overall packaging volume.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Temperature

If conventional heat sinks with additional bonding layers are used, then thermal management is attempted, but thermal resistance increases making thermal management challenging

Engineering Contradiction:

Improveheat removal efficiencyVSAvoidthermal management performance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The invention extracts and eliminates the additional bonding layers and thermal matching materials from the thermal path between the electronic components and the cooling structure. By forming cooling channels directly within the PCB, the thermal interface is simplified, reducing thermal resistance and improving heat transfer efficiency.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The cooling channels are pre-formed within the PCB structure during PCB manufacturing, before the electronic components are mounted. This preliminary integration ensures optimal thermal contact between the components and cooling structure, minimizing thermal resistance from the outset rather than adding corrective layers afterward.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If power electronic devices and gate drive devices are separate modules, then individual device functionality is maintained, but package size increases and parasitic inductance increases

Engineering Contradiction:

Improvedevice functionalityVSAvoidpackage size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The power electronic devices and gate drive devices are merged into a single integrated module on the same PCB substrate. This consolidation maintains the functionality of both device types while reducing the overall package size by eliminating the need for separate modules and interconnecting them through the PCB's integrated cooling and electrical structure.

Inventive Principle:

Principle #5Merging (Combining)

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 solution reduces packaging size, integrates power and gate drive devices compactly, and efficiently manages high heat flux, maintaining electronic assemblies within a suitable operating temperature range while minimizing parasitic inductance.

Implementation Method 1

The at least one jacket manifold has a fluid inlet and a fluid outlet defining a fluid flow area therebetween

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

The thermal compensation base layer is thermally coupled to the cooling jacket and one or more devices on the flexible printed circuit board

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11545874B2Thermal management assemblies for electronic assemblies circumferentially mounted around a motor using a flexible substrate

Publication Date: 2023.01.03 TOYOTA JIDOSHA KK

AI summary

An electronic assembly includes a flexible printed circuit board (PCB) circumferentially disposed around a motor and a thermal management assembly (TMA) thermally connected to the flexible PCB. One or more switching semiconductor devices are disposed on a first surface of the flexible PCB. The TMA includes a cooling jacket, at least one jacket manifold formed through the cooling jacket and a thermal compensation base layer thermally coupled to the cooling jacket. The cooling jacket is mounted around a circumference of the motor and has a mounting surface concentric with the circumference of the motor. The mounting surface is coupled to the first surface of the flexible PCB. The at least one jacket manifold has a fluid inlet and a fluid outlet defining a fluid flow area therebetween. The thermal compensation base layer is thermally coupled to the cooling jacket and the one or more switching semiconductor devices.