Alkaline Battery Sealing Member Moisture Control

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Solution Overview

Problem

Alkaline batteries face leakage issues due to a creeping phenomenon between the negative electrode current collector and the sealing member when stored in high humidity environments, especially when using nickel oxyhydroxide as the positive electrode active material, which reduces leakage resistance.

Innovation Solution

The use of a sealing member made from polyamide with an equilibrium moisture content of 0.9 to 1.3% at 50% relative humidity, combined with a sealant like asphalt or polybutene between the negative electrode current collector and the sealing member, ensures a reliable seal and prevents creeping, even in high humidity conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If nickel oxyhydroxide is used for the positive electrode active material to improve heavy load discharge characteristics, then the positive electrode potential is increased and heavy load discharge characteristics are improved, but the amount of oxygen gas generated by electrolysis of water is increased, which facilitates the creeping reaction between the negative electrode current collector and the sealing member, reducing leakage resistance

Engineering Contradiction:
Improveheavy load discharge characteristicsVSAvoidleakage resistance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent changes the material parameter of the sealing member from conventional materials to polyamide with specifically controlled moisture content (0.5-2.0%). This parameter change reduces the sealing member's reactivity with the negative electrode current collector, preventing the creeping phenomenon even when oxygen is present from nickel oxyhydroxide electrolysis, thus maintaining leakage resistance while allowing high power performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite approach by combining polyamide base material with moisture control techniques. The polyamide material itself has low moisture absorption characteristics, and when its moisture content is further reduced to 0.5-2.0%, it creates a composite effect that resists both the chemical creeping reaction and maintains sealing integrity under high humidity storage conditions

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If the moisture rate in the sealing member is increased due to storage in high humid environment, then the sealing member absorbs more moisture, but the creeping phenomenon between the negative electrode current collector and the sealing member is facilitated, making it difficult to prevent leakage

Engineering Contradiction:
Improvemoisture rate in sealing memberVSAvoidleakage resistance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent fundamentally changes the moisture parameter of the sealing member by selecting polyamide material and controlling its moisture content to 0.5-2.0%. This parameter change creates a sealing member that is inherently resistant to moisture absorption, preventing the moisture rate increase that would otherwise facilitate the creeping reaction between the negative electrode current collector and sealing member during high humidity storage

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses polyamide, a cost-effective material with inherently low moisture absorption properties, as the sealing member. This material choice provides an economical solution that effectively prevents moisture-related creeping phenomena without requiring complex or expensive alternative materials

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 configuration significantly enhances the leakage resistance of alkaline batteries, maintaining reliability and discharge performance even when stored in humid environments, and ensures excellent sealing properties.

Implementation Method 1

the moisture rate in the sealing member is increased

Methodology Applied
Scientific EffectMoisture absorption: Absorption (physical)

Implementation Method 2

6,12-nylon whose water absorption rate is low, dimensional change is small

Methodology Applied
Scientific EffectWater absorption: Absorption (physical)

Data Source

PatentEP2009717B1Alkaline cell
Publication Date: 2015.10.21 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2009717B1 patent drawingFigure 1
  • EP2009717B1 patent drawingFigure 2~3
  • EP2009717B1 patent drawingFigure 4

AI summary

An alkaline battery of the present invention includes a battery case, a power generating element housed in the interior of the battery case, and an assembled sealing part for closing the opening of the battery case. The assembled sealing part includes a resin sealing member. The sealing member includes a central cylindrical portion having a through-hole for inserting a shank of a negative electrode current collector therethrough, a peripheral cylindrical portion interposed between the periphery of the negative electrode terminal plate and the end portion of the opening of the battery case, and a joint portion for joining the central cylindrical portion and the peripheral cylindrical portion. The end portion of the opening of the battery case is curved such that the top of the peripheral cylindrical portion of the sealing member is wrapped therein, and the curved portion is crimped inward so that the periphery of the negative electrode terminal plate is fixed tightly. The sealing member includes polyamide having an equilibrium moisture content at a relative humidity of 50% of 0.9 to 1.7%.