Battery Cap Breaking-Line Venting for Internal Pressure Relief

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Solution Overview

Problem

Existing secondary batteries face safety issues due to internal pressure increases and thermal events, which can lead to component separation, structural collapse, and hinder smooth venting, potentially causing short circuits and thermal events.

Innovation Solution

A battery design featuring a cap with a fixed area and an open area containing breaking lines that bend and open when internal pressure exceeds a threshold, allowing for controlled venting without component separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If venting is performed to discharge internal gas when internal pressure increases, then internal pressure is reduced and explosion accidents are prevented, but component separation or structural collapse may occur leading to short circuits and thermal events

Engineering Contradiction:
Improveinternal pressureVSAvoidbattery safety
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The cap is divided into a fixed area and an open area separated by breaking lines. The open area is designed to break and open when internal pressure increases, allowing controlled venting. This segmentation enables the cap to maintain structural integrity in the fixed area while providing a controlled failure path in the open area, thus venting pressure without causing complete structural collapse or component separation.

Inventive Principle:
Principle #1Segmentation

2Productivity

If particles are rapidly ejected from the electrode assembly due to internal pressure increase, then thermal events may occur, but ejected particles may block the discharge route and hinder smooth venting

Engineering Contradiction:
Improveventing efficiencyVSAvoidparticle ejection and blockage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The breaking lines are pre-formed in the cap to create a predetermined failure path. When internal pressure increases, the cap breaks along these pre-formed lines, ensuring that the opening occurs in a controlled manner before particles can block the discharge route. This preliminary structural design prevents chaotic particle ejection and ensures smooth venting by guiding the opening process.

Inventive Principle:
Principle #10Preliminary action

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

Enables safe venting of internal gas by maintaining the battery's integrity and ensuring smooth discharge of gases during pressure increases or thermal events, preventing component separation and enhancing safety.

Implementation Method 1

If internal pressure of the battery housing increases to a predetermined pressure or more, at least some of the breaking lines may be broken so that at least a part of the open area is bent toward the fixed area and opened

Methodology Applied
Scientific EffectPressure increase: Pressure Increase

Data Source

PatentEP4693677A1Battery, and battery pack and vehicle including same
Publication Date: 2026.02.11 LG ENERGY SOLUTION LTD
  • EP4693677A1 patent drawingFigure 1~2
  • EP4693677A1 patent drawingFigure 3~4
  • EP4693677A1 patent drawingFigure 5

AI summary

A battery according to an embodiment of the present disclosure may include an electrode assembly having a winding-center hole formed by winding a laminate including a first electrode, a second electrode, and a separator interposed therebetween, a battery housing having an opening formed on one side and capable of accommodating the electrode assembly in an inner space, and a cap configured to cover the opening and including a fixed area fixed to the battery housing and an open area surrounded by the fixed area, and the open area may include a plurality of breaking lines formed to be recessed, and if internal pressure of the battery housing increases to a predetermined pressure or more, at least some of the breaking lines may be broken so that at least one area is bent toward the fixed area and opened.