High-Voltage Terminal Contact Insert With Multi-Point Force Distribution

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Solution Overview

Problem

High voltage electrical terminals in electric vehicles face challenges with contact resistance due to small contact points, leading to increased manufacturing costs and complexity, especially when using aluminum bus bars, and existing solutions like lamella contact inserts suffer from spring force relaxation at elevated temperatures.

Innovation Solution

A high voltage electrical connector design featuring a planar terminal, U-shaped retainer, and separate contact insert with paired negative and positive protrusions, where a resilient steel spring provides the connection force, eliminating the need for expensive plating by distributing contact force across multiple points and using copper-based materials for low resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If terminals are plated with low resistance material such as silver or gold to reduce contact resistance, then contact resistance decreases, but manufacturing time and cost increase

Engineering Contradiction:
Improvecontact resistanceVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The contact surface is segmented into multiple contact bumps (typically two or three) that distribute the contact force and create multiple contact points with the mating terminal, thereby reducing overall contact resistance without requiring expensive plating materials

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact bumps are designed with specific dimensional parameters (size, spacing, curvature) that optimize the contact pressure distribution and electrical contact quality, achieving low contact resistance through geometric optimization rather than material plating

Inventive Principle:
Principle #35Parameter changes

2Reliability

If copper-based lamella contact inserts are used to provide multiple contact points, then contact resistance decreases, but spring force relaxes at elevated temperatures

Engineering Contradiction:
Improvecontact resistanceVSAvoidspring force stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The contact insert is constructed from composite materials including a resilient base material (such as phosphor bronze or beryllium copper) that maintains spring force stability at elevated temperatures, combined with conductive properties for low contact resistance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The contact insert geometry is designed with specific parameters including bump height, spacing, and base thickness that optimize both the spring force characteristics and electrical contact properties, ensuring stable performance across temperature ranges

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the length of copper bus bar increases to reduce contact resistance, then electrical performance improves, but manufacturing difficulty and cost increase

Engineering Contradiction:
Improvecontact resistanceVSAvoidmanufacturing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The contact surface is segmented into multiple contact bumps that distribute electrical current across multiple points, effectively reducing contact resistance without requiring increased bus bar length or cross-section

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of reducing resistance by increasing the dimensional size (length) of the bus bar, the solution transitions to a different dimensional approach by creating multiple contact points through bumped surfaces, thereby reducing contact resistance without proportionally increasing material usage or manufacturing complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 significantly reduces contact resistance, maintains consistent force across multiple contact points, and eliminates the need for costly plating, while the steel spring minimizes temperature-induced relaxation, enhancing reliability and reducing manufacturing costs.

Implementation Method 1

a resilient spring that is disposed intermediate the spring and the terminal. The spring is configured to exert a normal connection force on the array of paired negative and positive protrusions

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The contact insert is formed from a copper-based material in order to provide a low resistance connection

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4283795A1High voltage electrical terminal with compliant contact insert
Publication Date: 2023.11.29 APTIV TECHNOLOGIES AG
  • EP4283795A1 patent drawingFigure 1~2
  • EP4283795A1 patent drawingFigure 3~4
  • EP4283795A1 patent drawingFigure 5~6

AI summary

An electrical connector (100) includes a generally planar terminal (102) and a U-shaped retainer (104). The electrical connector (100) also includes a resilient spring (112) disposed intermediate the terminal (102) and the retainer (104). A contact insert (114) distinct from the resilient spring (112) is disposed intermediate the spring (112) and the terminal (102). The contact insert (114) defines an array of paired negative and positive protrusions (118, 116). The spring (112) is configured to exert a normal connection force on the array of paired negative and positive protrusions (118, 116) and form electrical contact points between the terminal (102) and a planar mating terminal inserted into a gap between the spring (112) and the contact insert (114) through the array of paired negative and positive protrusions (118, 116). A method of manufacturing such an electrical connector is also provided.