Gel-Filled Cylindrical Terminal for Power Module Repair

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Solution Overview

Problem

Resin-sealed power semiconductor modules face issues with repairability and corrosion due to moisture ingress, especially under high humidity conditions, leading to increased contact and thermal resistance in cylindrical external terminal communication sections.

Innovation Solution

The power semiconductor module incorporates a metal cylinder external terminal communication section with a gel-filled hole or plated interior, preventing moisture ingress and corrosion by using a gel or plating only on the internal surfaces exposed to the wiring pattern and external terminals, ensuring effective sealing and reliable connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If cylindrical external terminal communication sections are used with press-in connection, then repairability is improved, but moisture ingress causes corrosion increasing contact and thermal resistance

Engineering Contradiction:

Improveterminal removal and reconnectionVSAvoidconnection stability under humidity

Core Design Contradiction:

Ease of repairVSReliability

Solution Approach 1:

A gel substance is introduced as an intermediary material filling the hollow interior of the cylindrical external terminal communication section. This gel acts as a barrier that prevents moisture from reaching the internal wiring pattern and terminal connection surfaces, thereby eliminating corrosion while maintaining the press-in connection structure's repairability benefits

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The gel creates a protected, moisture-free environment inside the cylindrical terminal communication section. By filling the hollow space with this inert gel medium, the internal surfaces are isolated from humid external conditions, preventing electrochemical corrosion reactions that would otherwise occur on the metal surfaces

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Reliability

If cylindrical external terminal communication sections are used with soldering, then connection reliability is improved, but moisture ingress at boundaries causes corrosion

Engineering Contradiction:

Improveconnection stabilityVSAvoidmoisture ingress at boundaries

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The gel serves as a moisture-blocking intermediary that extends to the boundary between the cylindrical terminal section and the transfer molding resin. This gel barrier prevents moisture from penetrating along the interface, protecting both the soldered connections and the boundary surfaces from corrosion

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

By filling the entire hollow interior including boundary regions with gel, a moisture-excluding environment is created that protects the solder joints and interface surfaces from humid conditions, eliminating the corrosion problem at boundaries

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Power

If external wiring is fixed by thread connection or soldering, then large-current operation is achieved, but repairability deteriorates

Engineering Contradiction:

Improvecurrent carrying capacityVSAvoidwiring removal

Core Design Contradiction:

PowerVSEase of repair

Solution Approach 1:

The terminal connection system is segmented into two independent parts: the cylindrical external terminal communication section (with press-in connection for easy repairability) and the internal wiring pattern connections (maintaining high current capacity through soldering). This segmentation allows each part to optimize for its specific function without compromising the other

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cylindrical terminal section acts as an intermediary component that bridges the external press-in terminal and the internal soldered wiring. This mediator allows the external connection to be easily replaceable while the internal high-current connections remain soldered for optimal electrical performance

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 design enhances the reliability and durability of the power semiconductor module by preventing corrosion and maintaining low contact and thermal resistance, even under humid conditions, while allowing for easy terminal removal and reconnection, thus improving repairability and operational efficiency.

Implementation Method 1

the hole of the cylindrical external terminal communication section is filled with gel

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Implementation Method 2

a high thermal conductive insulation layer joined to one surface of the metal heat sink

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS8258618B2Power semiconductor module

Publication Date: 2012.09.04 ROHM CO LTD

AI summary

The power semiconductor module includes: a circuit substrate; power semiconductor elements joined to element mounting portions of the wiring pattern on the circuit substrate; the cylindrical external terminal communication section joined to the wiring pattern; circuit forming means for connecting between portions that require electrical connection therebetween; and transfer molding resin for sealing these components. The cylindrical external terminal communication section is a metal cylinder, and the cylindrical external terminal communication section has a hole filled with gel.