Inclined Bonding Surface Conduction Path for Low Resistance

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Solution Overview

Problem

Conventional conduction paths experience high electrical resistance and heat generation due to metal oxide films formed during pressure welding, especially when larger currents flow, which is not adequately reduced by existing cold pressure welding methods.

Innovation Solution

A conduction path design featuring a first metal plate with a hole and a second metal plate with a press-fit portion, where an inclined bonding surface is formed on the wall and side surfaces, allowing for a bonding portion through metal flow in the periphery of the inclined surface, reducing electrical resistance by integrating clean, newly formed surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If cold pressure welding is used to connect conduction path forming plates, then the connection strength is improved, but metal oxide films remain on the bonding surfaces causing high electrical resistance

Engineering Contradiction:

Improveconnection strengthVSAvoidelectrical resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies preliminary action by forming the inclined bonding surfaces before the pressure welding process. The inclination is created during plate formation or surface preparation, ensuring that when pressure welding occurs, the geometry itself facilitates metal flow and oxide film removal. This preliminary geometric configuration enables the welding process to automatically achieve both strong mechanical bonding and low electrical resistance without requiring additional preprocessing steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes curvature by designing inclined bonding surfaces instead of flat surfaces. The inclination creates a wedge-shaped geometry that directs metal flow during pressure welding, enabling the bonding surfaces to mechanically break through oxide films and achieve intimate metal-to-metal contact. This curved/angled surface design transforms the welding process to simultaneously improve both connection strength and electrical conductivity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Ease of manufacture

If conventional pressure welding is used, then the manufacturing process is simple, but excessive heat is generated due to high electrical resistance in the bonding portion

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidheat generation

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The inclined bonding surfaces create a wedge geometry that facilitates metal flow during pressure welding. This geometric modification enables the process to remain simple while dramatically reducing electrical resistance at the bonding interface, thereby reducing I²R heat generation during current conduction without adding complex manufacturing steps.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Ease of manufacture

If flat bonding surfaces are used for pressure welding, then the manufacturing process is straightforward, but oxide films prevent adequate electrical contact

Engineering Contradiction:

Improvemanufacturing straightforwardnessVSAvoidelectrical contact quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces flat bonding surfaces with inclined surfaces that create a wedge-shaped bonding region. This geometric change enables the pressure welding process to mechanically disrupt and remove oxide films through controlled metal flow, achieving intimate metal-to-metal contact while maintaining manufacturing straightforwardness. The inclination angle is optimized to balance oxide film removal effectiveness with manufacturing simplicity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the geometric parameter of the bonding surface from flat to inclined, creating a wedge-shaped configuration. This parameter change transforms the pressure welding mechanism to enable automatic oxide film removal through metal flow, significantly improving electrical contact quality without complicating the manufacturing process. The inclination angle serves as a critical parameter that controls both oxide film removal and bonding strength.

Inventive Principle:

Principle #35Parameter changes

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 significantly lowers electrical resistance in the conduction path and semiconductor devices, improving conduction properties and reducing heat generation, with the electrical resistance being approximately one hundredth of conventional methods.

Implementation Method 1

a bonding portion formed by metal flow is formed in a region located in a periphery of the inclined bonding surface

Methodology Applied

Scientific EffectMetal flow: Plasticity

Data Source

PatentUS8754510B2Conduction path, semiconductor device using the same, and method of manufacturing conduction path, and semiconductor device

Publication Date: 2014.06.17 PANASONIC HOLDINGS CORP

AI summary

A conduction path includes a first conduction path forming plate (11) made of a first metal and having a through hole (13), and a second conduction path forming plate (15) made of a second metal and having a press-fit portion (17) press-fitted into the through hole. A wall surface of the through hole and a side surface of the press-fit portion forms an inclined bonding surface (18) inclined relative to a normal line of an overlap surface of the first conduction path forming plate and the second conduction path forming plate, and a bonding portion (25) formed by metal flow is formed in a region located in a periphery of the inclined bonding surface.