Galvanic Button Cell U-Shaped Edge Housing

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Solution Overview

Problem

Conventional galvanic button cells face challenges with sealing stability and capacity utilization due to sharp edges on housing covers and limitations in producing thin-walled sealing elements, which affect the internal volume and leakage resistance.

Innovation Solution

A galvanic element design featuring a housing cover with a U-shaped edge bent outwards, reducing sharp edges and allowing for a foil seal with improved stability and capacity utilization, using a deep-drawable foil like PEEK for the seal and a metal housing with thin walls for enhanced stability and sealing properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If injection molding is used to produce sealing elements, then sealing elements can be produced with good sealing properties, but the wall thickness cannot be less than 0.3 mm and the internal volume is reduced

Engineering Contradiction:
Improvesealing propertiesVSAvoidinternal volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent replaces the injection molding process with a deep-drawing process to produce the sealing element. This substitution allows the sealing element to be formed from a foil by deep-drawing using a drawing die and forming punch under vacuum, enabling wall thicknesses below 0.3 mm while maintaining sealing integrity through the forming process and subsequent crimping operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a thin-walled sealing element produced from foil with initial thickness of 0.1-0.3 mm. The deep-drawing process creates a cup-shaped molded part with uniform wall thickness of approximately 0.12 mm when starting with 0.15 mm foil, providing both sealing functionality and space efficiency.

Inventive Principle:
Principle #30Flexible shells and thin films

2Volume of stationary object

If conventional single-walled housing covers are used, then the internal volume is maximized, but the housing cover is unstable and has sharp cutting edges that can damage the foil seal

Engineering Contradiction:
Improveinternal volumeVSAvoidsealing stability
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The patent applies curvature by folding the edge of the housing cover outwards in a U-shape configuration. This curved edge design eliminates sharp cutting edges that could damage the foil seal while maintaining structural stability. The U-shaped fold creates a rounded profile that is mechanically more stable and safer for the sealing element.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The housing cover edge is segmented into distinct functional zones: a cylindrical section and an edge section with the U-shaped fold. This segmentation allows the edge portion to provide stability and protection for the foil seal, while the main body of the housing cover maintains optimal internal volume.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the edge of the housing cover is folded outwards in a U-shape, then stability is improved and sharp edges are eliminated, but the internal volume is reduced

Engineering Contradiction:
Improvehousing cover stabilityVSAvoidinternal volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The U-shaped edge fold is applied locally only to the edge section of the housing cover, not to the entire structure. This localized modification provides the necessary stability and eliminates sharp edges at the critical edge area where the foil seal contacts the housing cover, while minimizing the impact on the overall internal volume of the cell.

Inventive Principle:
Principle #3Local quality

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 design achieves improved capacity utilization and sealing stability with reduced risk of foil seal damage and enhanced leakage resistance, maintaining performance under high temperatures.

Implementation Method 1

a foil seal (503) which insulates the housing cup (502) from the housing cover (501)

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

A cup-shaped molded part is drawn from a heated foil using a drawing die and a forming punch under vacuum

Methodology Applied
Scientific EffectVacuum deformation: Vacuum

Implementation Method 3

the use of a sealing element which is produced from a foil by deep-drawing

Methodology Applied
Scientific EffectDeep-drawing: Deformation

Data Source

PatentEP2110869B1Galvanic element with innovative housing
Publication Date: 2016.01.27 VARTA MICROBATTERY GMBH
  • EP2110869B1 patent drawingFigure 1~3

AI summary

A galvanic cell, in particular a button cell, is described, comprising a housing cup, a housing lid and a foil seal that insulates the housing cup from the housing lid, wherein the housing lid has a lid base, a cylindrically formed section connected thereto and an adjoining edge section, and wherein the edge of the housing lid is bent outwards in a U-shape in the edge section.