Electronic Power Module Heat Sink Segmentation

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Solution Overview

Problem

Cordless power tools with brushless DC motors face challenges in heat dissipation as larger power devices, such as FETs and IGBTs, generate significant heat, requiring an effective integrated power, control, and switch module that meets heat dissipation needs.

Innovation Solution

An electronic switch module with a printed circuit board (PCB) featuring power switches, primary heat sinks, and a secondary heat sink, where the secondary heat sink is electrically insulated from the primary heat sinks using a thermally conductive thermal pad, and an insulating frame to manage heat dissipation and prevent electrical shorts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If larger power devices (FETs/IGBTs) are used to meet higher power requirements, then power capability increases, but heat generation increases significantly

Engineering Contradiction:

Improvepower capabilityVSAvoidheat generation

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The heat dissipation system is segmented into multiple independent heat sinks (first heat sink, second heat sink, third heat sink) that are distributed across different power devices. This allows heat to be dissipated from multiple locations simultaneously, reducing the thermal load on any single component while maintaining high power capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Thermal pads are introduced as intermediary elements between the power devices and heat sinks. These thermal pads facilitate efficient heat transfer from the power devices to the heat sinks, enabling the system to handle higher power levels without excessive temperature rise.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If multiple heat sinks are used to improve heat dissipation, then temperature control improves, but device complexity increases

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidnumber of heat sinks

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

Multiple heat sinks are merged into a single integrated housing structure that contains all heat dissipation components. This integration reduces the overall number of separate parts and simplifies assembly while maintaining the heat dissipation effectiveness of multiple heat sinks.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The housing structure serves multiple functions: it provides mechanical support, electrical insulation between heat sinks, and a unified mounting structure for all heat dissipation components. This multi-functionality reduces the need for additional specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Temperature

If heat sinks are electrically connected to power devices for heat dissipation, then heat transfer efficiency improves, but electrical short circuit risk increases

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidelectrical short circuit risk

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

Thermal pads serve as intermediary elements that provide both thermal conduction and electrical insulation. These pads allow heat to flow from power devices to heat sinks while preventing electrical current from passing through, thereby eliminating the risk of electrical short circuits.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses composite material structures where thermally conductive but electrically insulating materials (thermal pads) are combined with metallic heat sinks. This composite approach enables simultaneous achievement of efficient heat transfer and electrical isolation.

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

The solution effectively manages heat dissipation in high-power applications, allowing continuous operation up to 70 amps with the power switches and other components maintaining a temperature below 120 Celsius, enhancing the reliability and performance of the power tool.

Implementation Method 1

a secondary heat sink mounted on the primary heat sinks and securely fastened to at least one of the primary heat sinks via a fastener, the secondary heat sink being electrically insulated from at least one of the primary heat sinks

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a series of primary heat sinks mounted on the PCB in association with the power switches, and a secondary heat sink mounted on the primary heat sinks

Methodology Applied

Scientific EffectHeat dissipation: Heat Sink

Data Source

PatentUS11095193B2Electronic power module for a power tool having an integrated heat sink

Publication Date: 2021.08.17 BLACK & DECKER CORP

AI summary

An electronic switch module for a power tool having an electric motor is provided, including a printed circuit board (PCB), power switches mounted on the PCB and configured to switchably supply electric power from a power source to the electric motor, a series of primary heat sinks mounted on the PCB in association with the power switches, and a secondary heat sink mounted on the primary heat sinks. Output wires attached to the PCB to facilitate electrical connection between the power switches and the electric motor are passed through a slot of the secondary heat sink.