PET-PBT Non-Woven Gauntlet for Battery Burst Strength

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Solution Overview

Problem

Current non-woven gauntlets for lead-acid batteries face challenges in achieving high burst strength while maintaining low electrical resistance, which limits their application in demanding battery types such as stationary gel and flooded batteries due to mechanical weaknesses and increased electrical resistance when attempting to enhance mechanical properties.

Innovation Solution

A non-woven, cartridge belt type gauntlet is developed using spunbond, needled, and flat thermobonded bicomponent PET-PBT fabric, assembled at regular intervals with a thermoplastic resin impregnation, offering improved mechanical strength and reduced electrical resistance through specific manufacturing processes and material properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If point-bonded polyester spunbond material is used to provide fabric strength through melting PET filament, then manufacturing process is simplified, but electrical resistance increases and burst strength is insufficient

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidburst strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent uses a composite non-woven fabric structure combining PET (polyethylene terephthalate) and PBT (polybutylene terephthalate) filaments. The PBT component provides lower melting point for bonding while PET contributes to mechanical strength and oxidation resistance. This composite approach resolves the contradiction by achieving both adequate burst strength and manufacturability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters by introducing PBT filaments with lower melting point (around 220°C) compared to PET (around 260°C). This parameter change allows the fabric to be bonded at lower temperatures, reducing electrical resistance while maintaining manufacturing simplicity. The bonding point density and filament composition are optimized to balance strength and conductivity.

Inventive Principle:
Principle #35Parameter changes

2Strength

If more bonding points are created by hot calendar to increase fabric strength, then burst strength improves, but electrical resistance increases

Engineering Contradiction:
Improvefabric strengthVSAvoidelectrical resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the bonding mechanism by using PBT's lower melting point to create bonds at reduced temperature and pressure. This results in fewer but more effective bonding points that maintain fabric integrity while preserving electrical conductivity. The bonding point size and distribution are optimized to minimize electrical resistance pathways.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates localized bonding zones rather than uniform bonding across the entire fabric. The hot calendar applies heat and pressure selectively to create discrete bonding points only where needed for structural integrity, leaving other areas with lower bonding density to maintain electrical conductivity. This local quality approach resolves the contradiction between strength and electrical resistance.

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 new gauntlet achieves a burst pressure of over 16 bars and electrical resistance of less than 180 mΩ.cm², enhancing both mechanical and electrical properties simultaneously, allowing for efficient constraining of active mass and maintaining battery capacity over its life, even in aggressive filling technologies and demanding applications.

Implementation Method 1

the latter having a lower melting point and being melted during calendaring in order to impart the fabric strength

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

flat thermobonded bicomponent PET-PBT nonwoven fabric

Methodology Applied
Scientific EffectThermal bonding:

Implementation Method 3

the non-woven fabric is impregnated with a thermoplastic resin

Methodology Applied
Scientific EffectImpregnation: Absorption (physical)

Data Source

PatentEP1878073B1Non-woven gauntlets for batteries
Publication Date: 2008.08.27 AMER SIL SA
  • EP1878073B1 patent drawingFigure 1~2
  • EP1878073B1 patent drawingFigure 3~4
  • EP1878073B1 patent drawingFigure 5

AI summary

The present invention concerns non-woven, cartridge belt type gauntlet for lead acid batteries comprising two sheets of spunbond, needled and flat calendared thermobonded bicomponent PET-PBT nonwoven fabric assembled together at regular intervals.