Button Cell Anode Mixture Uniform Mixing via Water Mediator

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Solution Overview

Problem

Existing methods for producing button cells with composite electrodes face issues such as segregation and uneven distribution of binder and conductive agents, leading to incomplete discharge and reduced energy capacity due to dry mixing processes.

Innovation Solution

A method involving an anode mixture of metal particles, binder, and conductive agent contacted in the presence of water, followed by mixing with an electrolyte and closure in a button cell housing, which ensures uniform adherence and reduced segregation of components, using a gassing inhibitor to prevent gas development.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If dry mixing is used to produce anode mixture, then manufacturing process is simple, but segregation occurs and distribution of binder and conductive agent becomes uneven

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoiduniformity of binder and conductive agent distribution
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Water is introduced as an intermediary substance to facilitate mixing of the anode components. The water allows binder and conductive agent particles to be uniformly distributed among metal particles through wet mixing, preventing segregation that occurs in dry mixing processes

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mixing process transitions from dry state to wet state by changing the physical parameter of moisture content. This parameter change enables better distribution of components and prevents segregation, directly addressing the uniformity problem

Inventive Principle:
Principle #35Parameter changes

2Reliability

If intensive dry mixing is performed to achieve good contact between particles, then electrical conductivity improves, but segregation and uneven distribution occur

Engineering Contradiction:
Improveelectrical contact qualityVSAvoidhomogeneity of electrode composition
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

Water acts as a mediating fluid that enables uniform distribution of conductive agents and binders around metal particles. This wet mixing approach achieves good electrical contact through uniform distribution without the segregation problems of dry mixing

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention explicitly aims to achieve homogeneous distribution of all electrode components (metal particles, binder, conductive agent) through wet mixing. The water medium ensures that conductive agents are evenly distributed, creating a homogeneous electrode composition

Inventive Principle:
Principle #33Homogeneity

3Object-affected harmful factors

If gassing inhibitor is added to prevent hydrogen development, then safety improves, but electrode composition complexity increases

Engineering Contradiction:
Improvegassing and hydrogen developmentVSAvoidelectrode composition complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The gassing inhibitor is extracted as a separate functional component from the basic electrode mixture. This additive specifically addresses hydrogen development issues without requiring fundamental changes to the electrode structure, managing safety while maintaining relatively simple composition

Inventive Principle:
Principle #2Taking out (Extraction)

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 method enhances electrical contact and conductivity, allows for efficient discharge, and improves safety by preventing gassing and maintaining structural integrity during electrochemical changes.

Implementation Method 1

The binder ensures the mechanical stability of the electrode, in particular it should ensure that the particles of the electrochemically active material make contact with one another and with the current collector

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

gassing as a result of electrolyte decomposition or due to volumetric dynamics of the particles during charging and discharging processes

Methodology Applied
Scientific EffectElectrochemical reaction: Electrolysis

Data Source

PatentEP2722913B1Anode mixture, button cell with an anode comprising a metal particle and their preparation
Publication Date: 2018.11.28 VARTA MICROBATTERY GMBH

AI summary

The method comprises: introducing an anode mixture comprising, as constituents, metal particles, binder, conducting agent and optionally a gassing inhibitor into a button cell housing; admixing the mixture with an electrolyte; and liquid-tight sealing of the housing. The constituents of the mixture are contacted in the presence of water before introducing into the housing, and after the contacting, the water is partially removed from the mixture. The constituents are intermingled to each other. The water is added to the mixture composing three constituents. The method comprises: introducing an anode mixture comprising, as constituents, metal particles, binder, conducting agent and optionally a gassing inhibitor into a button cell housing; admixing the mixture with an electrolyte; and liquid-tight sealing the housing. The constituents of the mixture are contacted in the presence of water before introducing into the housing, and after the contacting, the water is partially removed from the mixture. The constituents are intermingled to each other. The water is added to the mixture composing three constituents. The binder is admixed with the water or dissolved in the water. The admixture or the solution is added to the metal particles. The conducting agent is subsequent to extensive intermingling of these constituents. The binder and the conducting agent are admixed with the water and/or dissolved in the water. The admixture and/or the solution are applied to the surface of the metal particles. The water is partially removed after contacting by drying. A comminuting step follows after the contacting. The binder is processable in water. The gassing inhibitor is a surfactant substance. The mixture includes 0.05-5 wt.% of the conducting agent, 0.05-5 wt.% of the binder and/or 0.05-1 wt.% of the gassing inhibitor in a dry condition. The contacting of the mixture occurs in a fluidized-bed unit. An independent claim is included for an anode mixture for button cells.