Polyallylamine Sealing Layer for Nonaqueous Electrolyte Cell Lead Wire

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Solution Overview

Problem

The adhesion and sealing properties between a sealable container and a lead conductor in nonaqueous electrolyte cells degrade over time due to moisture permeation, leading to corrosion and detachment, especially in automotive applications where long-term resistance to electrolytes is required.

Innovation Solution

Incorporating a layer of polyallylamine between the metal layer and the lead conductor at the sealing portion, which enhances adhesion and resistance to electrolytes, using a polyallylamine polymer or its copolymers like diallylamine with sulfur dioxide to improve corrosion prevention and adhesiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a thermal adhesive layer is used to bond the sealable container and lead conductor, then adhesion is enhanced, but corrosion and detachment occur over time due to moisture permeation

Engineering Contradiction:
ImproveadhesionVSAvoidresistance to corrosion
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

An intermediate layer composed of polyallylamine is introduced between the thermal adhesive layer and the lead conductor. This intermediate layer serves as a protective barrier that prevents moisture from reaching the lead conductor, thereby preventing corrosion while maintaining the adhesion provided by the thermal adhesive layer. The polyallylamine layer acts as a mediator that blocks harmful moisture penetration without compromising the bonding strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing structure is designed as a composite multi-layer system consisting of the sealable container, thermal adhesive layer, polyallylamine intermediate layer, and lead conductor. This composite structure combines the adhesion properties of the thermal adhesive with the moisture-blocking properties of polyallylamine, achieving both strong bonding and long-term corrosion resistance.

Inventive Principle:
Principle #40Composite materials

2Strength

If the thermal adhesive layer has high fluidity during heat-sealing, then adhesiveness is enhanced, but short-circuiting may occur between the metal layer and lead conductor

Engineering Contradiction:
ImproveadhesivenessVSAvoidshort-circuiting
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The polyallylamine intermediate layer is positioned between the thermal adhesive layer and the lead conductor to serve as an insulating barrier. This intermediate layer prevents direct contact between the metal layer and lead conductor, eliminating the risk of short-circuiting while allowing the thermal adhesive layer to maintain high fluidity and adhesiveness during the heat-sealing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the sealable container structure is simplified, then manufacturing is easier, but long-term resistance to electrolytes in automotive applications is compromised

Engineering Contradiction:
Improvesealing structureVSAvoidresistance to electrolytes
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The polyallylamine intermediate layer provides self-protective functionality by inherently blocking moisture and electrolyte penetration. This layer automatically prevents corrosion without requiring additional complex protective structures or maintenance, thereby maintaining ease of manufacture while significantly improving long-term resistance to electrolytes in demanding automotive applications.

Inventive Principle:
Principle #25Self-service

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 use of polyallylamine layers maintains high adhesion and sealing properties even after prolonged exposure to electrolytes, preventing corrosion and detachment, particularly effective for nickel or nickel-plated lead conductors.

Implementation Method 1

a layer composed of a polyallylamine is provided at a part between the metal layer and the lead conductor and in contact with the lead conductor

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

the sealable container and each of the lead conductors are bonded (fusion-bonded) together through a thermal adhesive layer

Methodology Applied
Scientific EffectThermal adhesion: Heating

Data Source

PatentEP2600435B1Electrical component, nonaqueous-electrolyte cell, and lead wire and sealable container both for use therein
Publication Date: 2015.08.19 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP2600435B1 patent drawingFigure 1~2
  • EP2600435B1 patent drawingFigure 3A~3B
  • EP2600435B1 patent drawingFigure 4~5

AI summary

Provided are an electrical part, a nonaqueous electrolyte cell, and a lead wire and a sealable container which are used therein. The electrical part includes a sealable container having a metal layer, and a lead conductor extending from the inside to the outside of the sealable container, the sealable container and the lead conductor being fusion-bonded at a sealing portion, in which the sealing portion at least partially has a layer composed of a polyallylamine at a part between the metal layer and the lead conductor and in contact with the lead conductor, and therefore, adhesion and sealing properties can be enhanced in the initial state and in a state of being in contact with an electrolytic solution.