Secondary Battery Safety Vent Buffering Space Design

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Solution Overview

Problem

Secondary batteries face a safety issue where the deformation of the safety vent during the crimping process reduces the short-circuit pressure, leading to potential battery failure or explosion when a short circuit occurs.

Innovation Solution

A secondary battery design featuring a safety vent with a bending unit and buffering space, including a standing part, support part, and contact part, which buffers pressure during crimping, and an optional buffer member made of rubber, synthetic resin, or silicone, to maintain the short-circuit pressure and prevent deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the top cap assembly is coupled to the can through crimping process, then the assembly is securely fastened, but the safety vent operation part is deformed and short-circuit pressure is reduced

Engineering Contradiction:
Improvecoupling strengthVSAvoidshort-circuit pressure
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent introduces a buffering space between the safety vent operation part and the can opening to cushion the external force applied during crimping. This buffering space absorbs the mechanical stress before it reaches the safety vent, preventing deformation while allowing secure coupling of the top cap assembly to the can.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the safety vent operation part is made more robust to resist deformation, then short-circuit pressure is maintained, but the device complexity increases

Engineering Contradiction:
Improveshort-circuit pressureVSAvoidsafety vent structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a buffering space as an intermediary element between the safety vent operation part and the external crimping force. This buffering space acts as a mediator that protects the safety vent from direct mechanical stress, maintaining short-circuit pressure without requiring structural modifications to the safety vent itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If buffering space is introduced to protect safety vent, then short-circuit pressure is maintained, but the device complexity increases

Engineering Contradiction:
Improveshort-circuit pressureVSAvoidsafety vent structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The buffering space can be formed using flexible materials or thin film structures that conform to the existing safety vent geometry. This approach adds minimal structural complexity while effectively cushioning the crimping force and maintaining the short-circuit pressure characteristics.

Inventive Principle:
Principle #30Flexible shells and thin films

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 solution effectively maintains the short-circuit pressure, preventing additional reactions and battery explosion or ignition by disconnecting the safety vent and current interruption member, ensuring consistent battery function.

Implementation Method 1

a buffering space is defined between the bending unit and the main body... The buffering space may buffer a pressure during the crimping

Methodology Applied
Scientific EffectPressure buffering: Damping

Implementation Method 2

a safety vent provided in the top cap assembly to discharge a gas when an inner pressure of the can member increases

Methodology Applied
Scientific EffectPressure-driven gas discharge: Pressure Gradient

Data Source

PatentEP3614451B1Secondary battery
Publication Date: 2023.01.18 LG ENERGY SOLUTION LTD
  • EP3614451B1 patent drawingFigure 1
  • EP3614451B1 patent drawingFigure 2
  • EP3614451B1 patent drawingFigure 3

AI summary

The present invention relates to a secondary battery, and more particularly, to a secondary battery that is capable of preventing a short-circuit pressure from being reduced when short circuit occurs. Also, the secondary battery of the present invention includes a can member accommodating an electrode assembly, a top cap assembly covering an opening of the can member, and a safety vent provided in the top cap assembly to discharge a gas when an inner pressure of the can member increases, wherein the safety vent includes a main body and a bending unit in which an outer edge of the main body is bent, wherein a buffering space is defined between the bending unit and the main body.