Sealed Battery Vent Structure for Stable Gas Discharge

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Solution Overview

Problem

Sealing assemblies in sealed batteries face challenges in achieving stable gas discharge performance while maintaining shock resistance, as conventional designs with thin engraved parts for gas discharge are prone to damage from external forces.

Innovation Solution

A sealing assembly with a projection having an inclined part and a thin section that fractures under internal pressure, utilizing tensile stress to ensure stable gas discharge and enhanced shock resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the vent member is reduced to enable gas discharge at lower internal pressure, then gas discharge performance is improved, but shock resistance deteriorates

Engineering Contradiction:
Improvegas discharge performanceVSAvoidshock resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The vent member employs local quality by creating a thin part with reduced thickness in a specific region of the inclined part. This thin part is positioned to fracture first under internal pressure, enabling gas discharge, while the rest of the vent member maintains sufficient thickness for shock resistance. The local thinning is achieved through controlled formation during molding, creating a thickness gradient that optimizes both gas discharge and mechanical strength.

Inventive Principle:
Principle #3Local quality

2Strength

If the thickness of the vent member is increased to improve shock resistance, then strength is improved, but gas discharge performance deteriorates

Engineering Contradiction:
Improveshock resistanceVSAvoidgas discharge performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention applies parameter changes by systematically varying the thickness of the vent member along the inclined part. The thickness transitions from a maximum at the outer periphery to a minimum at the thin part location. This continuous parameter change allows the structure to withstand external shocks with sufficient thickness while ensuring that a specific region fractures at a predetermined internal pressure threshold for reliable gas discharge.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the thickness of the vent member is made uniform, then manufacturing is simplified, but gas discharge stability deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidgas discharge stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Rather than making the entire vent member uniformly thin, the invention applies local quality by maintaining varying thickness only in the inclined part where the thin part is formed. Other portions of the vent member can have uniform or different thickness profiles, balancing manufacturing simplicity with the localized thickness variation needed for stable gas discharge performance.

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 stable gas discharge performance and improved shock resistance by allowing the thin section of the inclined part to fracture under internal pressure, maintaining thickness for durability.

Implementation Method 1

a thin part that has a smaller thickness than a portion except the inclined part and takes priority in fracturing when an internal pressure of the battery case exceeds a predetermined threshold

Methodology Applied
Scientific EffectFracture: Fracture Mechanics

Data Source

PatentEP3902024B1Sealed battery
Publication Date: 2026.04.01 SANYO ELECTRIC CO LTD
  • EP3902024B1 patent drawingFigure 1
  • EP3902024B1 patent drawingFigure 2
  • EP3902024B1 patent drawingFigure 3

AI summary

The purpose of the present disclosure is to provide a sealed battery that demonstrates stable exhaust performance when an abnormality occurs in the battery, and that has excellent shock resistance. This sealed battery that is an example of an embodiment of the present disclosure is provided with: a battery case that includes a bottomed cylindrical outer can and an opening-sealing body that closes an opening section of the outer can; and an electrode body that is accommodated inside the battery case. The opening-sealing body includes a metal plate, and the metal plate includes a protruding section that bulges toward the outside of the battery case, and a flange section that is formed on the circumference of the protruding section. The protruding section includes an inclination section that inclines inward from the radial outside of the opening sealing body so as to be progressively separated from the electrode body, wherein a thin wall section, which has a thickness less than portions other than the inclination section and is preferably broken when the inner pressure of the battery case exceeds a predetermined threshold, is formed in at least a portion of the inclination section.