Flat Battery Negative Electrode Mixture Particle Size Control

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Solution Overview

Problem

The attachment of insulating powder to supply pins during the molding of negative electrode mixtures in flat primary batteries hinders normal supply and reduces productivity, especially when using zinc or zinc alloys in a gel state.

Innovation Solution

Incorporating a non-metal resin powder with a specific particle size range (60% to 140% of the zinc powder's average diameter) and water repellency, such as polytetrafluoroethylene, polypropylene, polyamide, or acrylic resin, into the negative electrode mixture to adjust viscoelasticity and prevent attachment to supply pins, while maintaining necessary electric capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If insulating powder is added to the negative electrode mixture to adjust viscoelasticity, then handling properties are improved, but the insulating powder attaches to supply pins during molding, reducing productivity

Engineering Contradiction:
Improvehandling propertiesVSAvoidproductivity
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The invention changes the particle size parameter of the insulating powder from fine particles to coarse particles with an average particle diameter of 110 μm or more. This parameter change prevents the insulating powder from attaching to the supply pin during molding, thereby resolving the contradiction between improving handling properties and maintaining productivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality by specifying that only coarse insulating powder (average particle diameter 110 μm or more) should be used in the negative electrode mixture, rather than uniformly using fine insulating powder throughout. This localized quality change (coarse particles at specific locations in the mixture) prevents attachment to supply pins while maintaining the necessary viscoelasticity adjustment function

Inventive Principle:
Principle #3Local quality

2Productivity

If the ratio of insulating powder is increased to improve handling properties, then productivity may be enhanced, but the electric capacity of the battery decreases

Engineering Contradiction:
ImproveproductivityVSAvoidelectric capacity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention changes the particle size parameter of the insulating powder to coarse particles (average particle diameter 110 μm or more), which allows for better handling and productivity while the specific particle size range helps minimize the negative impact on electric capacity by reducing unnecessary attachment and ensuring proper distribution

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If fine insulating powder is used in the negative electrode mixture, then viscoelasticity can be adjusted, but the powder attaches to supply pins during molding

Engineering Contradiction:
ImproveviscoelasticityVSAvoidattachment to supply pin
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The invention changes the particle size parameter from fine to coarse (average particle diameter 110 μm or more), which eliminates the attachment problem while maintaining the ability to adjust viscoelasticity through the insulating powder's presence in the mixture

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention converts the potential harm of insulating powder attachment into a benefit by using coarse particles that do not attach, thereby turning the molding process into a more reliable and productive operation while still achieving viscoelasticity adjustment

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

Enhances handling properties and productivity by preventing insulating powder attachment to supply pins, ensuring consistent electric capacity and reduced variation, thus improving the assembly process of flat primary batteries.

Implementation Method 1

the insulating powder has water repellency

Methodology Applied
Scientific EffectWater repellency: Hydrophobe

Implementation Method 2

the viscoelasticity of the negative electrode mixture can be suitably adjusted

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP2660901B1Flat primary battery, negative electrode mixture for flat primary battery, and method for manufacturing flat primary battery
Publication Date: 2017.09.06 SEIKO INSTR INC
  • EP2660901B1 patent drawingFigure 1
  • EP2660901B1 patent drawingFigure 2A~2D
  • EP2660901B1 patent drawingFigure 3

AI summary

A flat primary battery capable of enhancing the productivity and a method for manufacturing the same are disclosed. The flat primary battery is a flat alkaline primary battery including a positive electrode mixture, a negative electrode mixture, and an electrolytic solution in a can, wherein the negative electrode mixture includes a zinc powder or a zinc alloy powder and an insulating powder of a non-metal which does not react with an electrolytic solution and which has an average particle diameter of 110 µm or more, the value of which is from 60 % to 140 % of an average particle diameter of the zinc powder or zinc alloy powder.