Power Terminal Using Stainless Steel Clamp for High Current

Solution Overview

Problem

Copper terminals used in high power applications suffer from relaxation at elevated temperatures, leading to reduced electrical conductivity and increased resistance, limiting current-carrying capacity to 60 amps or less due to size constraints and the need for copper alloys with lower conductivity to prevent relaxation.

Innovation Solution

The use of stainless steel clamp-like members with low relaxation properties at elevated temperatures, combined with high conductivity copper terminals, maintains compression force and contact area, allowing for increased current-carrying capacity without the need for lower conductivity copper alloys.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If copper terminals are used for high power applications, then electrical conductivity is improved, but relaxation occurs at elevated temperatures reducing clamping force and contact area

Engineering Contradiction:

Improveelectrical conductivityVSAvoidclamping force stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The terminal is divided into two distinct materials: copper for the electrical contact portion (providing high conductivity) and stainless steel for the clamping portion (providing temperature-stable spring force). This segmentation allows each material to optimize its function without the trade-offs of using a single material.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The terminal uses a composite construction combining copper and stainless steel materials. The copper section provides superior electrical conductivity while the stainless steel section maintains stable mechanical properties at elevated temperatures, resolving the contradiction between conductivity and thermal stability.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If copper alloys with lower conductivity are used to prevent relaxation, then clamping force stability is improved, but current-carrying capacity is reduced

Engineering Contradiction:

Improveclamping force stabilityVSAvoidcurrent-carrying capacity

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The terminal is divided into two distinct materials: copper for the electrical contact portion (providing high conductivity) and stainless steel for the clamping portion (providing temperature-stable spring force). This segmentation allows each material to optimize its function without the trade-offs of using a single material.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The terminal uses a composite construction combining copper and stainless steel materials. The copper section provides superior electrical conductivity while the stainless steel section maintains stable mechanical properties at elevated temperatures, resolving the contradiction between conductivity and thermal stability.

Inventive Principle:

Principle #40Composite materials

3Force

If terminal size is increased to provide greater spring force, then clamping force is improved, but the overall size of the electrical distribution box increases

Engineering Contradiction:

Improvespring forceVSAvoidterminal size

Core Design Contradiction:

ForceVSVolume of moving object

Solution Approach 1:

The terminal uses a composite construction combining copper and stainless steel materials. The stainless steel provides superior spring properties allowing high clamping force in a compact design, while the copper provides electrical conductivity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the material parameters by using stainless steel instead of copper for the spring portion. Stainless steel has higher elastic modulus and maintains spring force at elevated temperatures, allowing smaller terminal dimensions while maintaining required clamping force.

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

This solution enables fuses and connectors to handle higher currents, such as up to 80 or 100 amps, while maintaining high conductivity and stability, by using stainless steel clamps with copper terminals, thus overcoming the limitations of copper alloys in high power applications.

Implementation Method 1

copper is susceptible to relaxation (i.e., loss of spring force) as the temperature increases

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

Copper has good electrical conductivity properties

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS8366497B2Power terminal

Publication Date: 2013.02.05 LEAR CORP

AI summary

An electrical connector formed to have at least one or more pairs of opposing legs extending from a body portion where each leg extends to a contact point where an inner surface of each opposing leg contact. A spring clip can be positioned over one or more of the opposing legs to increase a compressive force. The spring clip may include an alignment feature to limit clip rotating and/or pitching.