Polymer Sacrificial Mandrels for Anode Can Fabrication

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Solution Overview

Problem

Conventional sacrificial mandrel-based anode can fabrication processes for extended wear hearing instrument batteries face issues such as surface defects, incompatibility with certain materials due to hydrochloric acid usage, and waste generation, which limit the performance and stability of metal-air batteries.

Innovation Solution

The method involves using a polymer sacrificial mandrel that dissolves in an organic solvent for anode can fabrication, allowing for the use of a wider range of metals and reducing waste, as organic solvents do not attack metals like tin and indium, and enabling the reuse of solvents through distillation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If zinc sacrificial mandrels are used with hydrochloric acid removal, then the anode can is formed, but certain metals (tin and indium) cannot be used for the innermost layer due to acid attack

Engineering Contradiction:

Improvemetal selection for innermost layerVSAvoidbattery performance and stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the chemical parameter of the dissolution medium from hydrochloric acid to organic solvents (such as ethyl acetate, acetone, or toluene). This parameter change allows the innermost layer to be made of metals like tin and indium that are incompatible with acid-based removal processes, thereby expanding material selection while maintaining battery reliability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary substance - the organic solvent - that mediates between the zinc sacrificial mandrel and the metal layers. The organic solvent dissolves the zinc mandrel without attacking the metal innermost layer, enabling the use of metals that would otherwise be incompatible with the sacrificial mandrel process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If hydrochloric acid is used to remove zinc mandrel, then the mandrel is dissolved, but large amounts of waste are generated requiring fresh acid for each batch

Engineering Contradiction:

Improvemandrel removal processVSAvoidacid consumption and waste generation

Core Design Contradiction:

Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent applies the discarding and recovering principle by replacing consumable hydrochloric acid with reusable organic solvents. The organic solvent dissolves the zinc mandrel and can then be recovered through distillation and reused for subsequent batches, eliminating the need to continuously purchase and dispose of fresh acid.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The organic solvent system is self-sustaining through distillation recovery. The solvent that dissolves the zinc mandrel is recovered, purified through distillation, and reused without requiring external replenishment, making the process self-service and eliminating continuous waste generation.

Inventive Principle:

Principle #25Self-service

3Ease of manufacture

If die cast zinc mandrels are used, then the mandrel structure is formed, but surface defects (pores, sinkholes, bubbles) require additional chemical etching or finishing

Engineering Contradiction:

Improvemandrel formationVSAvoidsurface quality of mandrel

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent employs disposable injection-molded polymer mandrels that are designed to be sacrificed after a single use. These mandrels are inexpensive enough that they can be discarded after one fabrication cycle, eliminating the need for costly surface finishing operations to correct defects.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the mechanical die-casting process with chemical injection molding of polymers. This substitution eliminates the surface defects inherent in die-casting (pores, sinkholes, bubbles) because injection-molded polymers can achieve superior surface quality without requiring subsequent chemical etching or mechanical finishing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach results in superior battery performance by facilitating the use of metals like tin and indium, minimizing waste, and eliminating the need for chemical etching and fresh acid usage, leading to more efficient and stable anode cans.

Implementation Method 1

an anode can sacrificial mandrel formed from a polymer that dissolves in the presence of an organic solvent

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

which allows the solvent to be distilled and reused

Methodology Applied

Scientific EffectDistillation: Distillation

Data Source

PatentEP3298648B1Anode can sacrificial mandrels and fabrication methods

Publication Date: 2020.02.12 SONOVA AG

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Figure 7A~8C

AI summary

An anode can fabrication method including the steps of depositing metal onto an anode can sacrificial mandrel formed from a polymer that dissolves in the presence of an organic solvent and dissolving the sacrificial mandrel with the organic solvent.