Battery Cap-Up Notch Venting for Controlled Pressure Release

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Solution Overview

Problem

Secondary batteries face safety risks due to increased pressure and temperature caused by gas generation during abnormal conditions, leading to potential ignition and performance deterioration.

Innovation Solution

A secondary battery design featuring a cap-up with notches in the base plate, terminal part, or connection part that rupture at a set pressure to facilitate controlled gas emission, enhancing stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the battery is sealed without a safety vent, then the structural integrity and sealing are improved, but the safety risk due to pressure buildup is worsened

Engineering Contradiction:
Improvesealing integrityVSAvoidpressure buildup risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

A notch is pre-formed in the cap-up structure at a location designed to rupture at a specific pressure threshold. This preliminary structural feature ensures that when abnormal pressure builds up inside the battery, the cap-up will rupture at the predetermined notch location, providing automatic pressure relief without requiring additional safety vent components.

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If a safety vent is added to the battery, then the pressure relief capability is improved, but the device complexity is worsened

Engineering Contradiction:
Improvepressure relief capabilityVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The safety vent function is merged into the cap-up structure itself by forming a notch directly in the cap-up material. This integration eliminates the need for separate safety vent components, reducing structural complexity while maintaining pressure relief capability. The cap-up serves dual purposes: sealing the battery and providing pressure relief through the embedded notch.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If the cap-up thickness is reduced to facilitate notch rupture, then the gas emission capability is improved, but the mechanical strength is worsened

Engineering Contradiction:
Improvegas emission capabilityVSAvoidcap-up strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The cap-up structure employs non-uniform thickness distribution, with the majority of the cap-up maintaining sufficient thickness for mechanical strength and sealing, while a localized region at the notch position has reduced thickness to facilitate rupture at the predetermined pressure threshold. This local thinning creates a weak point that preferentially fails under pressure, enabling gas emission without compromising the overall structural integrity of the cap-up.

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 notched cap-up structure effectively manages internal pressure by allowing controlled gas discharge, preventing explosions and improving battery stability and performance.

Implementation Method 1

a notch is provided in at least one of the base plate, the terminal part, and the connection part so as to be ruptured at a set pressure within the can

Methodology Applied
Scientific EffectPressure-induced rupture: Fracture Mechanics

Data Source

PatentEP4597697A1Secondary battery
Publication Date: 2025.08.06 SAMSUNG SDI CO LTD
  • EP4597697A1 patent drawingFigure 1
  • EP4597697A1 patent drawingFigure 2
  • EP4597697A1 patent drawingFigure 3A~3B

AI summary

Provided is a secondary battery including an electrode assembly, in which a notch is provided in a cap-up so that the cap-up is ruptured at a set internal pressure so a gas inside the battery is easily discharged to improve stability of the battery, preventing chain rupture or explosion. The secondary battery includes an electrode assembly, a can configured to accommodate the electrode assembly, and a cap assembly configured to seal an upper portion of the can and having a cap-up comprising a base plate, a terminal part protruding upwardly from an upper side of the base plate and disposed at a center of the cap-up, and a connection part configured to connect the base plate to the terminal part. A notch is provided in at least one of the base plate, the terminal part, or the connection part to be ruptured at a set pressure within the can.