Secondary Battery Cap Vent Structure for Rapid Gas Discharge

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Solution Overview

Problem

Existing secondary batteries face challenges in safely discharging internal gas, which can lead to potential explosions due to inefficient venting mechanisms.

Innovation Solution

The secondary battery design includes a safety vent with a notch exposed through an opening in the cap-up, allowing rapid venting of internal gas, and a gasket to prevent electrical short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional safety vent design is used, then the structure is simple, but the gas discharge efficiency is insufficient leading to potential explosions

Engineering Contradiction:
ImprovesafetyVSAvoidgas discharge efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The safety vent is divided into multiple through-holes instead of a single opening, increasing the total venting area and improving gas discharge efficiency while maintaining structural simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cap assembly has different regions with different functions: the safety vent region for gas discharge, the current interruptive device region for electrical isolation, and the gasket region for sealing, allowing each part to optimize its local function for overall safety

Inventive Principle:
Principle #3Local quality

2Productivity

If a current interruptive device with through holes is used, then gas discharge is improved, but electrical short circuit risk increases

Engineering Contradiction:
Improvegas discharge efficiencyVSAvoidelectrical short circuit
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

A gasket is introduced as an intermediary component between the current interruptive device and the cap-up, providing electrical insulation while allowing gas to pass through the through-holes, thus resolving the conflict between gas discharge and electrical isolation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cap assembly uses composite construction combining conductive components (current interruptive device) with insulating materials (gasket), allowing simultaneous achievement of electrical isolation and gas permeability

Inventive Principle:
Principle #40Composite materials

3Productivity

If the notch is not exposed through the cap-up opening, then the structure is simpler, but gas venting speed is insufficient

Engineering Contradiction:
Improveventing speedVSAvoidcap assembly structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The notch is extracted and exposed through the cap-up opening, creating a direct pathway for gas to escape from the battery interior to the exterior environment, significantly increasing venting speed while adding minimal structural complexity

Inventive Principle:
Principle #2Taking out (Extraction)

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 effectively prevents explosions by ensuring rapid gas discharge, improving safety and reducing thermal diffusion propagation to adjacent batteries.

Implementation Method 1

a safety vent having a predetermined notch configured to rupture by high-pressure gas generated in the battery

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

a current interruptive device gasket for surrounding an outer circumference of the current interruptive device

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP4235929B1Secondary battery
Publication Date: 2026.03.18 SAMSUNG SDI CO LTD
  • EP4235929B1 patent drawingFigure 1
  • EP4235929B1 patent drawingFigure 2
  • EP4235929B1 patent drawingFigure 3

AI summary

The present invention relates to a secondary battery which can easily vent internal gas, thereby enhancing safety. Disclosed as an example is a secondary battery comprising: an electrode assembly; a case in which the electrode assembly is accommodated; and a cap assembly which is coupled to the top of the case and comprises a cap-up having opening, a safety vent provided under the cap-up and having a notch to be ruptured at a predetermined pressure or higher, and a cap-down provided under the safety vent and electrically connected to the electrode assembly, wherein the notch is exposed through the opening.