Pressure Piece Shear Contact for Battery Cell Corrosion

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Solution Overview

Problem

Existing battery packs face challenges in maintaining low contact resistance and preventing corrosion, especially under high current conditions and over time, which increases power loss due to mechanical contact issues and corrosion of electrical connections.

Innovation Solution

A pressure-stable contact element with an angled surface is used, combined with a pressure piece that applies shearing forces, and a circumferential seal filled with conductive paste to ensure reliable and corrosion-resistant electrical contact between conductors, utilizing an electrically insulating material for the pressure piece and roughened surfaces for enhanced conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a clamping wedge is used to press arresters onto a busbar, then mechanical contact pressure is provided, but the electrical connection shows corrosion over time and contact resistance increases

Engineering Contradiction:
Improvemechanical contact pressureVSAvoidelectrical connection stability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

A pressure-stable contact element made of corrosion-resistant material is introduced as an intermediary between the arrester and the busbar. This contact element maintains stable electrical connection over time by preventing direct contact between incompatible materials, thereby reducing corrosion while maintaining adequate contact pressure through the pressure piece.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If conductors are connected with high current capacity, then sufficient output voltage is achieved, but power loss increases due to contact resistance

Engineering Contradiction:
Improveoutput voltageVSAvoidpower loss
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The contact element features a roughened contact surface that changes the surface parameters to enhance electrical conductivity. The roughened surface increases the actual contact area and improves metal-to-metal contact, thereby reducing contact resistance and minimizing power loss while maintaining high current capacity.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a common pressure piece is used for multiple contact elements, then device complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvenumber of pressure piecesVSAvoidcontact alignment accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

A single pressure piece is designed to perform multiple functions by pressing several contact elements simultaneously. The pressure piece incorporates multiple pressure surfaces angled at specific angles to accommodate different contact elements, reducing the total number of pressure pieces needed while maintaining precise contact through the standardized angular geometry.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 achieves a high-current-resistant, low-loss contact that remains effective over time, preventing corrosion and maintaining low contact resistance, ensuring reliable electrical connectivity and long-term performance.

Implementation Method 1

at least one of the mutually opposite contact surfaces has a roughened surface with elevations which, under contact pressure, penetrate the opposite material in an electrically contacting manner. This design ensures that an aluminum oxide layer formed on a conductor made of aluminum is broken up when the pressure and shearing forces are applied

Methodology Applied
Scientific EffectMechanical penetration: Deformation

Implementation Method 2

shearing forces are applied when the arrester is pressed against the contact element. These shearing forces act between the contact surface of the contact element and the contact surface of the arrester and are formed by counter-parallel forces. In order to build up high shear forces, the contact surface on the contact element is at an angle to the longitudinal central axis of the pressure piece

Methodology Applied
Scientific EffectShear stress: Shear Stress

Data Source

PatentEP2418715B1Pressure piece for contacting an electric lead
Publication Date: 2014.03.19 ADS-TEC GMBH
  • EP2418715B1 patent drawingFigure 1~2
  • EP2418715B1 patent drawingFigure 3~4
  • EP2418715B1 patent drawingFigure 5~6

AI summary

The invention relates to a battery pack comprising a plurality of individual flat battery cells (6), each having a cathode arrester (17) and an anode arrester (18). Two arresters (17, 18) of adjacent flat battery cells (5, 6) are electrically connected to each other. To achieve good contact, an arrester (17, 18) is electrically pressed against a contact element (30) by means of a pressure piece (25) that applies shear forces.