Button Cell Housing Recesses for Electrode Interlock

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Solution Overview

Problem

The connection of metallic negative electrodes to the housing in button cells is often problematic, leading to inadequate electrical contact, necessitating additional measures like arrester networks or complex substrate designs.

Innovation Solution

A button cell design featuring a multi-part housing with a positive mechanical connection between the housing and electrodes, utilizing recesses with undercuts in the cell cover to ensure a form-fitting engagement of the electrodes, eliminating the need for additional conductor networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If metallic negative electrodes are stamped directly into the negative half-part of the housing, then the electrode connection is simplified, but the electrical connection reliability deteriorates

Engineering Contradiction:
Improveconnection structureVSAvoidelectrical connection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention transitions from a simple planar stamping connection to a three-dimensional form-fitting connection by introducing recesses with undercuts in the housing. The electrode engages behind the undercut in the recess, creating a mechanical interlock that provides reliable electrical connection while maintaining structural simplicity.

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

2Reliability

If an arrester network is welded into the negative half-section of the housing, then the electrical connection reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveelectrical connectionVSAvoidconnection structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the arrester network component by replacing it with a form-fitting connection structure integrated directly into the housing. The recess with undercut provides the necessary mechanical and electrical connection without requiring separate conductor networks or welding operations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the inside of the button cell housing is roughened using a stamp, then the adhesion of electrode materials is improved, but the manufacturing complexity increases

Engineering Contradiction:
ImproveadhesionVSAvoidhousing processing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of roughening the entire inside surface of the housing, the invention applies the form-fitting connection structure locally at specific recesses where electrode engagement is needed. This localized approach provides sufficient adhesion and mechanical connection without the complexity of overall surface roughening.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2427927B1Button cell and method for production thereof
Publication Date: 2013.06.05 VARTA MICROBATTERY GMBH
  • EP2427927B1 patent drawingFigure 1A~1C
  • EP2427927B1 patent drawingFigure 2A~2B

AI summary

A button cell is described having a multiple-part housing for holding electrodes and a separator, wherein there is an interlocking connection between the housing and at least one of the electrodes, in particular the anode. Furthermore, a method is also described for the production of button cells, in which an electrode material is introduced into a housing half-part (1), the inner face of which has at least one depression (2) provided with at least one undercut (3), so as to create an interlocking connection between the resultant electrode and the housing half-part (1).