Battery Sealing Protrusions for Electrode Lead Bonding

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Solution Overview

Problem

The existing sealing processes for pouch type lithium secondary batteries face challenges in achieving a tight seal due to a limited application area of heat and pressure, leading to potential electrolyte leakage and moisture penetration, especially when the sealing-planned parts adjacent to the electrode leads are not properly bonded.

Innovation Solution

A sealing apparatus with protrusion parts on the sealing blocks that extend in the direction of the electrode assembly and opposite to it, allowing for increased application of heat and pressure on the sealing-planned parts, thereby ensuring a more effective bonding of the sealing-planned parts to the electrode leads and insulating films, even when they are extended.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If strong pressure is applied to correspond to the outer shape of the electrode leads, then the sealing-planned parts can be in close contact with the electrode leads, but the area where heat can be applied is considerably narrowed

Engineering Contradiction:
ImprovepressureVSAvoidheat application area
Core Design Contradiction:
ForceVSArea of stationary object

Solution Approach 1:

The sealing blocks are designed with protrusion parts that extend in the direction of the electrode assembly and opposite to it, adding a dimensional element to the sealing structure. This allows the sealing blocks to apply pressure and heat not only on the main sealing surface but also on extended portions of the sealing-planned part, effectively increasing the heat application area despite the narrow boundary surface between electrode leads and sealing parts.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the sealing-planned parts are bonded to the lead member indirectly through the insulating film, then the insulating film is pushed in the protruding direction by pressure, but the insulating film deviates to the outer side of the sealing-planned portions

Engineering Contradiction:
Improvebonding processVSAvoidsealing precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The protrusion parts of the sealing blocks are designed to extend in the direction of the electrode assembly and opposite to it, performing a preliminary action of guiding and containing the insulating film before the main bonding process occurs. This preliminary structural arrangement prevents the insulating film from deviating to the outer side during pressure application, ensuring proper bonding between the sealing-planned parts and the lead member.

Inventive Principle:
Principle #10Preliminary action

3Shape

If the boundary surface area between electrode leads and sealing-planned parts is narrow, then the structure is compact, but the sealing-planned parts are difficult to be completely bonded to the electrode leads

Engineering Contradiction:
Improveboundary surfaceVSAvoidsealing reliability
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The sealing blocks are designed with localized protrusion parts that extend in the direction of the electrode assembly and opposite to it, creating different functional zones on the sealing block surface. These protrusion parts specifically target the narrow boundary surface areas between electrode leads and sealing-planned parts, applying concentrated pressure and heat to ensure complete bonding in these critical localized regions, thereby improving sealing reliability without changing the overall compact structure.

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

This solution enhances the sealing force of the battery case, preventing electrolyte leakage and moisture penetration by ensuring a tighter seal of the sealing-planned parts, even in areas with a narrow heat application area, thereby improving the reliability and durability of the battery cell.

Implementation Method 1

bonding the sealing-planned part by applying pressure and heat to the sealing-planned part

Methodology Applied
Scientific EffectHeat: Heating

Implementation Method 2

bonding the sealing-planned part by applying pressure and heat to the sealing-planned part

Methodology Applied
Scientific EffectPressure: Compression

Implementation Method 3

the protrusion part further applies heat and pressure to a corresponding portion of the sealing-planned part extending along an end portion of the electrode lead

Methodology Applied
Scientific EffectHeat: Heating

Implementation Method 4

the protrusion part further applies heat and pressure to a corresponding portion of the sealing-planned part extending along an end portion of the electrode lead

Methodology Applied
Scientific EffectPressure: Compression

Data Source

PatentEP3340334B1Sealing device for battery case with increased pressing and heat application area
Publication Date: 2021.03.10 LG ENERGY SOLUTION LTD
  • EP3340334B1 patent drawingFigure 1
  • EP3340334B1 patent drawingFigure 2
  • EP3340334B1 patent drawingFigure 3

AI summary

The present invention provides a sealing apparatus having a structure in which an application area of pressure and heat is increased by a pair of sealing blocks and a pressurization part extending from the sealing block. In the sealing apparatus according to the present invention based on the structure, when the sealing-planned part is pressurized, heat and pressure may be applied to the sealing-planned part or an insulating film to be extended, and thus an electrode lead and the sealing-planned part adjacent thereto may be firmly bonded.