Flat Conductor Contact Welding With Curved Stainless Steel Tabs

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Solution Overview

Problem

Existing methods for connecting electrical contact elements to flat conductors in motor vehicle electrical systems are cumbersome, leading to increased installation space and weight, and lack a defined exit direction, which complicates the process and may result in unreliable connections.

Innovation Solution

A method using a stainless steel contact element with a curvature that is friction welded to the flat conductor, utilizing ultrasonic friction welding or other processes to create a compact and reliable connection, allowing for easy and cost-effective integration with minimal space requirements and favorable electrochemical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If stainless steel bolts are welded onto flat conductors to connect electrical contact elements, then reliable electrical connection is achieved, but installation height increases and only one defined outgoing direction is possible

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidinstallation height
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The invention transitions from a protruding bolt connection (vertical dimension) to a planar friction welding connection (horizontal dimension). The contact element is welded directly to the flat conductor surface, eliminating the need for bolts that extend beyond the conductor plane, thus reducing installation height while maintaining connection reliability

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

Solution Approach 2:

The invention removes the intermediate stainless steel bolt component from the connection system. By directly friction welding the contact element to the flat conductor, the bolt is extracted from the assembly, eliminating the height increase and multi-directional complexity associated with bolt protrusion

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If stainless steel bolts are used to connect electrical contact elements to flat conductors, then electrical connection is achieved, but device complexity increases due to additional components and steps

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidconnection process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the contact element and flat conductor into a single welded assembly, eliminating the separate bolt component. The friction welding process combines two components directly, reducing the total number of parts and simplifying the connection process while maintaining reliable electrical connection

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The stainless steel bolt is completely removed from the connection system. The invention extracts this intermediate component and replaces it with a direct friction welding joint between the contact element and flat conductor, thereby reducing device complexity and the number of assembly steps

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If traditional bolting methods are used to connect electrical contact elements, then connection is achieved, but sealing against electrolytes becomes necessary

Engineering Contradiction:
Improveconnection stabilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention uses a material pairing (stainless steel contact element and aluminum flat conductor) that is inherently resistant to galvanic corrosion and electrolyte damage. This eliminates the need for additional sealing components or protective coatings, simplifying manufacturing while ensuring long-term connection stability in automotive environments

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention employs a composite material system consisting of stainless steel and aluminum with favorable electrochemical properties. This material combination resists galvanic corrosion and electrolyte attack without requiring additional sealing measures, thereby simplifying the manufacturing process while maintaining connection reliability

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

This method enables simple, compact, and cost-effective connection of electrical contact elements to flat conductors, ensuring a stable and reliable welded connection with reduced installation space and no need for additional sealing, while maintaining good mechanical and electrical properties.

Implementation Method 1

A friction welding process is then carried out in which the curvature of the electrical contact element arranged on the flat conductor is set into relative movement to the flat conductor by means of a friction welding tool, thereby creating a welded connection between the flat conductor and the contact element

Methodology Applied
Scientific EffectFriction welding: Friction Welding

Implementation Method 2

The friction welding process can be carried out using ultrasonic friction welding, for example, in which a sonotrode, which is part of the friction welding tool, is pressed onto the electrical contact element in the area of the curvature with a certain pressure or force. The sonotrode exerts a high-frequency, oscillating movement on the electrical contact element, resulting in the aforementioned relative movement between the curvature of the stainless steel sheet and the flat conductor. The resulting friction heats and plasticizes the curvature and the flat conductor, creating the welded connection.

Methodology Applied
Scientific EffectUltrasonic friction welding: Ultrasonic Vibration

Data Source

PatentEP3750214B1Method for connecting at least one electrical contact element to a flat conductor for a vehicle electrical system of a motor vehicle
Publication Date: 2024.06.05 LISA DRAXLMAIER GMBH
  • EP3750214B1 patent drawingFigure 1~2
  • EP3750214B1 patent drawingFigure 3~4
  • EP3750214B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for connecting at least one electrical contact element (3) to a flat conductor (1) for a vehicle electrical system of a motor vehicle, comprising the following steps: providing the at least one electrical contact element (3), which has a contact region (6) for contacting a further contact element, and which is produced at least from a stainless steel plate (S) with a curved section (7), which protrudes beyond the rest of the stainless steel plate (S); arranging the electrical contact element (3) on the flat conductor (1) with its curved section (7); carrying out a friction welding process, in which a relative movement of the curved section (7) of the electrical contact element (3) arranged on the flat conductor (1) relative to the flat conductor (1) is brought about by a friction welding tool, and a welded joint is thereby produced between the flat conductor (1) and the electrical contact element (3).