Cylindrical Battery Insulation Board Structure for Gas Vent Retention

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Solution Overview

Problem

Existing cylindrical batteries face the issue of the insulating plate being released to the outside of the battery during gas discharge due to increased gas discharge rates, potentially causing high-temperature gas to escape and burn adjacent batteries.

Innovation Solution

The insulating plate is designed with a body and folded portions that bias it towards the electrode assembly, preventing release during gas discharge by engaging with the grooved portion of the outer can.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the insulating plate is made with uniform thickness, then the manufacturing is simple, but the insulating plate may be detached during gas discharge

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidinsulating plate retention
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The insulating plate employs varying thickness across different regions: the center portion has a first thickness while the outer circumferential portion has a second thickness that is greater than or equal to 130% and less than or equal to 300% of the first thickness. This local quality variation strengthens the insulating plate at the outer circumferential portion to prevent detachment during gas discharge, while maintaining reasonable manufacturing complexity.

Inventive Principle:
Principle #3Local quality

2Reliability

If the insulating plate outer circumferential thickness is increased to prevent detachment, then the retention improves, but the manufacturing complexity increases

Engineering Contradiction:
Improveinsulating plate retentionVSAvoidinsulating plate structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by specifying that the outer circumferential portion thickness is greater than or equal to 130% and less than or equal to 300% of the center portion thickness. This quantitative parameter definition provides a clear manufacturing guideline that balances improved retention with controlled structural complexity, avoiding excessive design complications.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If gas discharge rate increases during abnormality, then the safety response improves, but the insulating plate may be released without being held

Engineering Contradiction:
Improvegas discharge rateVSAvoidinsulating plate retention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements preliminary anti-action by pre-reinforcing the outer circumferential portion of the insulating plate with increased thickness (130%-300% of center thickness) before gas discharge occurs. This preventive structural enhancement ensures the insulating plate can resist detachment forces during high-rate gas discharge events, countering the potential release issue before it happens.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP4679620A1Cylindrical battery
Publication Date: 2026.01.14 PANASONIC ENERGY CO LTD
  • EP4679620A1 patent drawingFigure 1
  • EP4679620A1 patent drawingFigure 2~3
  • EP4679620A1 patent drawingFigure 4~5

AI summary

A cylindrical battery (10) comprises: an electrode body (14) in which a positive electrode (11) and a negative electrode (12) are wound with a separator (13) therebetween; an exterior can (20) in which the electrode body (14) is accommodated; a sealing body (19) which is mounted on a grooved part (28) that is formed along the circumferential direction of the exterior can (20) with a gasket (24) therebetween; and an upper insulation board (30) which is disposed between the grooved part (28) and the electrode body (14). The upper insulation board (30) has a body (31) which is mounted on the electrode body (14), and a folded part (32), the outer circumferential part of which is folded towards the body (31). The upper insulation board (30) is biased by the folded part (32) towards the electrode body (14).